DBNPA

Dibromonitrilopropionamide (DBNPA)
DBNPA is supplied generally as solid Powder form or as 20 % liquid form.

DBNPA or 2,2-dibromo-3-nitrilopropionamide is a quick-kill biocide that easily hydrolyzes under both acidic and alkaline conditions.
DBNPA is preferred for its instability in water as it quickly kills and then quickly degrades to form a number of products, depending on the conditions, including ammonia, bromide ions, dibromoacetonitrile, and dibromoacetic acid.
DBNPA acts similar to the typical halogen biocides.

2,2-dibromo-3-nitrilopropionamide (DBNPA) is an industrial biocide which is used in recirculating and once-through cooling systems, as well as other industrial applications

2,2-Dibromo-3-Nitrilopropionamide (DBNPA) is a kind of wide spectrum, high efficiency, industrial germicide that can be used in paint and as an adhesive.

What is DBNPA?
DBNPA formula is 2,2-Dibromo-3-Nitriloproprionamide.

When is DBNPA used?
It is used in recirculating cooling water systems and closed loop systems to control microbial growth. Its advantages are it is effective over a wide pH range against the microorganisms typically found in these systems. It is good for killing aerobic bacteria, fair for anaerobic bacteria and fungi, and poor for algae.

What is the feed rate of DBNPA?
12 to 48 ppm is for maintenance dosage. 480 max slug dose. Use dipslides to monitor performance. This product is 5% in concentration.

2,2-dibromo-2-cyanoacetamide (DBNPA)
CAS : 10222-01-2
Synonymes : 2,2-Dibromo-2-carbamoylacetonitrile;2,2-Dibromo-2-cyanoacetamide;Acetamide, 2,2-dibromo-2-cyano-;Acetamide, 2-cyano-2,2-dibromo-;alpha, alpha-Dibromo-alpha-cyanoacetamide;alpha,alpha-Dibromo-alpha-cyanoacetamide;DBNPA;Dibromocyanoacetamide;UNII-7N51QGL6MJ;USEPA/OPP Pesticide Code: 101801;2,2-dibromo-2-cyano-acetamide;2,2-dibromo-2-cyano-ethanamide;2,2-Dibromo-3-nitrilopropionamide;3-02-00-01641 (Beilstein Handbook Reference);540978_ALDRICH;BRN 1761192;C3H2Br2N2O;Caswell No. 287AA;CID25059;Dibromocyano acetic acid amide;…

Applications:
It is used as anti-microbial agent, controlling bacterial, fungal and algal growth in industrial water systems like cooling towers, pulp and paper mill process water, oil-recovery systems and air-conditioning systems.

2,2-Dibromo-2-carbamoylacetonitrile
2,2-dibromo-2-cyano-acetamide
2,2-dibromo-2-cyano-ethanamide
2,2-Dibromo-2-cyanoacetamide
2,2-Dibromo-3-nitrilopropionamide
3-02-00-01641 (Beilstein Handbook Reference)
540978_ALDRICH
Acetamide, 2,2-dibromo-2-cyano-
Acetamide, 2-cyano-2,2-dibromo-
alpha,alpha-Dibromo-alpha-cyanoacetamide
alpha, alpha-Dibromo-alpha-cyanoacetamide
BRN 1761192
C3H2Br2N2O
Caswell No. 287AA
CID25059
DBNPA
Dibromocyanoacetamide
Dibromocyano acetic acid amide
EINECS 233-539-7
EPA Pesticide Chemical Code 101801
FR-2220
HSDB 6982
LS-3155
NCGC00164203-01
NCIOpen2_006184
NSC 98283
NSC98283
SBB008529
UNII-7N51QGL6MJ
USEPA/OPP Pesticide Code: 101801
XD-1603
XD-7287l Antimicrobial
XD 7287L
ZINC01638458

Common name: DBNPA
Chemical name: 2,2-Dibromo-2-cyanoacetamide
2,2-dibromo-3-nitrilopropionamide
EC No.: 233-539-7
CAS No.: 10222-01-2

2,2-Dibromo-3-nitrilopropionamide (DBNPA) has been documented as a useful antimicrobial agent in a number of industrial applications, due to its rapid rate of kill at relatively low use-concentrations, broad spectrum of antimicrobial activity, chemical non-persistence, and low environmental impact.
2,2-Dibromo-3-nitrilopropionamide (DBNPA) is available commercially as a 20% active solution in a water/polyethylene glycol blend.
A discussion on the use of a non-oxidizing, fast-acting antimicrobial agent with a short chemical half-life, in various aspects of metalworking-fluid production and utilization, presented at the 59th STLE Annual Meeting (Toronto, Ontario, Canada 5/17-20/2004), covers lubricant degradation/stability-microbial; indirect food-contact approvals for DBNPA; decomposition pathways; microbiology; DBNPA as a preservative enhancer; efficacy of DBNPA; and methods of addition of DBNPA to water-based systems

DBNPA is used in a wide variety of applications. Some examples are in papermaking as a preservative in paper coating and slurries.
DBNPA is also used as slime control on papermachines, and as a biocide in hydraulic fracturing wells and in cooling water

Continuous DBNPA dosage with a dose of 1 mg/L is a strategy to prevent or restrict biofouling in water treatment systems
(A. Siddiquia,*, I. Pinelb,*, E.I. Prestb, Sz.S. Bucsa, M.C.M. van Loosdrechtb, J.C. Kruithofc,J.S. Vrouwenveldera,b,c)
2,2-Dibromo-3-nitrilopropionamide (DBNPA) has been documented as a useful antimicrobial agent in a number of industrial applications, due to its rapid rate of kill at relatively low use-concentrations, broad spectrum of antimicrobial activity, chemical non-persistence, and low environmental impact.
It is available commercially as a 20% active solution in a water/polyethylene glycol blend.
A discussion on the use of a non-oxidizing, fast-acting antimicrobial agent with a short chemical half-life, in various aspects of metalworking-fluid production and utilization, presented at the 59th STLE Annual Meeting (Toronto, Ontario, Canada 5/17-20/2004), covers lubricant degradation/stability-microbial; indirect food-contact approvals for DBNPA; decomposition pathways; microbiology; DBNPA as a preservative enhancer; efficacy of DBNPA; and methods of addition of DBNPA to water-based systems

2,2-dibromo-2-cyanoacetamide
2,2-dibromo-2-cyanoacetamide
2,2-dibromo-2-cyanoacetamide (DBNPA)
Acetamide, 2,2-dibromo-2-cyano-

Translated names
2,2-dibrom-2-cianacetamidas (DBNPA) (lt)
2,2-Dibrom-2-ciānacetamīds (DBNPA) (lv)
2,2-dibrom-2-cyanacetamid (DBNPA) (da)
2,2-Dibrom-2-cyanacetamid (DBNPA) (de)
2,2-dibrom-2-cyanoacetamid (DBNPA) (sv)
2,2-dibrom-2-kyanacetamid (DBNPA) (cs)
2,2-dibromi- 2-syaaniasetamidi (DBNPA) (fi)
2,2-dibromo- 2-cianoacetammide (DNBPA) (it)
2,2-dibromo-2-cianoacetamid (DBNPA) (sl)
2,2-Dibromo-2-cianoacetamida (DBNPA) (es)
2,2-dibromo-2-cianoacetamida (DBNPA) (pt)
2,2-dibromo-2-cianoacetamidă (DBNPA) (ro)
2,2-dibromo-2-cijanoacetamid (DBNPA) (hr)
2,2-dibromo-2-cyanoacetamide (DBNPA) (mt)
2,2-dibromo-2-cyanoacetamide (DBNPA) (no)
2,2-dibromo-2-cyanoacétamide (DBNPA) (fr)
2,2-dibromo-2-cyjanoacetamid (DBNPA) (pl)
2,2-dibromo-2-tsüanoatseetamiid (DBNPA) (et)
2,2-Dibroom-2-cyaanaceetamide (DBNPA) (nl)
2,2-dibróm-2-cianoacetamid (DBNPA) (hu)
2,2-dibróm-2-kyanoacetamid (DBNPA) (sk)
2,2-διβρωμο-2-κυανακεταμίδιο (DBNPA) (el)
2,2-дибромо-2-цианоацетамид (DBNPA) (bg)

IUPAC names
2, 2-Dibromo-3-nitrilopropionamide
2,2 DIBROMO-3-NITRILOPROPIONAMIDE
2,2-Dibrom-3-nitrilpropionamid
2,2-Dibromo-2-cyanoacetamide
2,2-dibromo-2-cyanoacetamide
2,2-dibromo-3-cyanopropanamide
2,2-Dibromo-3-nitrilopropionamide

DBNPA

Dibromo-3-nitrilopropionamide

Dibromocyanoacetamide

2 2 Dibromo 3 Nitrilopropionamide (DBNPA) Guide Part 1
dalong
The full name of DBNPA is 2-2-dibromo-3-nitriloproion amide.
It is a broad-spectrum and efficient industrial fungicide. DBNPA is used to prevent bacteria and algae from growing in papermaking, industrial circulating cooling water, mechanical lubricants, pulp, wood, paint, and plywood. 2-2-Dibromo-3-Nitrilopropionamide (DBNPA) is currently popular at home and abroad. Organic bromine fungicides.

Sterilization mechanism of DBNPA
DBNPA molecules can rapidly penetrate microbial cell membranes. Act on certain protein groups. The cells are normally redox terminated. Its branches can also selectively bromine or oxidize specific enzyme metabolites of microorganisms. Eventually leads to cell death.

1. DBNPA product performance
1.1 Broad spectrum, fast and efficient sterilization performance
DBNPA has a broad spectrum of bactericidal properties. It has a good killing effect on bacteria, fungi, yeast, algae, biological slime and pathogenic microorganisms that threaten human health.

2 2 Dibromo 3 Nitrilopropionamide (DBNPA) is characterized by extremely fast sterilization and high efficiency. The sterilization rate can reach over 99% in 5-10 minutes. DBNPA was compared to the other three biocides. The results showed that when the same bactericidal effect was achieved, DBNPA was used at a dose of the only 7.5ppm, which is much lower than the other three fungicides.

comparison of sterilization performance
1.2 Good inhibition of peeling on biofilms
When DBNPA is added to the system, its active components act rapidly on planktonic microorganisms. It can be quickly sterilized. At the same time, the permeability of organic bromine is good. The active component of the agent rapidly penetrates the metal surface. Acts on smaller microbial communities. It allows rapid depolymerization and prevents the formation of biofilms.

For systems that have formed biofilms, the active components do not react with the slime layers in the biofilm. It quickly penetrates deeper into the biofilm. A microbial community acting at the junction of a biofilm and a metal surface. Destruction of its viscosity causes the biofilm to fall off.

Experimental studies have shown that for the peeling of the biofilm at the age of 7 days, the smaller dosage can achieve the same peeling effect, and the advantage of the peeling effect on the biofilm is very obvious.

1.3 Effectively kill Legionella
The control effect of 2 2 Dibromo 3 Nitrilopropionamide (DBNPA) on Legionella is very significant.

Studies have shown that 2-5mg/L DBNPA (effective), can reduce Legionella 5-6 logs within 3 hours. 2-4 mg/L DBNPA (effective) can reduce Legionella by 6 logs for 2 hours. For Legionella in biofilms. 10mg/L DBNPA (effective), 12 hours can completely kill Legionella. Additional data indicate that low doses of organic bromine and glutaraldehyde are used in combination. Legionella in biofilms can be lowered to undetectable levels.

1.4 Rapid degradation
DBNPA is rapidly degraded to carbon dioxide, ammonia and bromine salts upon completion of bactericidal action. It does not cause the enrichment of harmful ions in the water. There is no impact on the environment, so emissions are not restricted. This is a distinguishing feature of organic bromine biocides that distinguish them from other non-oxidizing biocides.

The relationship between DBNPA half-life and temperature and pH
pH value   6.0   6.7   7.3   7.7   8.0   8.9   9.7
Half-life, h   155.0   37.0   8.8   5.8   2.0   0.34   0.11
Temperature, °C   25   25   25   25   25   25   25
1.5 Effectively kill sulfate-reducing bacteria
The oilfield sewage has a high sulfate content, which is very beneficial to the reproduction of sulfate-reducing bacteria. The large-scale reproduction of sulfate-reducing bacteria will lead to an increase in the content of H2S in water. 2 2 Dibromo 3 Nitrilopropionamide (DBNPA) acts rapidly on sulfate-reducing bacteria. It can be quickly killed before it reacts with sulfate to form H2S.

Experimental studies have shown that 10 mg/L can effectively control the sulfate-reducing bacteria in the system, so as to completely remove the sulfide in the re-injection system and protect the system from sulfide corrosion.

2. DBNPA application areas and how to use
2.1 DBNPA application area
2 2 Dibromo 3 Nitrilopropionamide (DBNPA) is widely used as a disinfectant, bactericide, algicide, slime stripper, and mildew inhibitor in the following aspects.

The circulating cooling water system, oil field water injection system, bactericide, algicide, slime stripper in the paper industry.

Preservatives for paints, waxes, inks, detergents, surfactants, slurries, resins.

Process water, air purifier system in the machinery manufacturing industry, fungicides, and algicides in municipal water landscapes.

2.2 DBNPA usage
When used as a water treatment slime stripper, the DBNPA is added at a concentration of 30-50 mg/L.

Used as a water treatment bactericide for circulating cooling water systems. According to water retention, DBNPA is added at 10-20 mg/L.

DBNPA
DBNPA ORGANCIDE is the biocide to control the growth of bacteria, fungi and algae in cooling water systems.

It is particularly suitable for cooling towers, water used in the paper industry, air conditioning systems.
It can also be used in the short-term protection of certain industrial products such as polymer dispersions.

PROPERTIES
Rapid anti-microbial action and decomposition into non-toxic by-products: causes a 5-log reduction in the number of bacteria in just 15 minutes.

FEATURES
– Fully soluble in water and most light alcohols and glycols
– Avoid alkaline solutions, hydrolyzes under neutral to alkaline conditions.
– No compatibility problems, however there may be interactions if added at the same time as other preservatives.
– Composition: 2,2-dibromo-3-nitrilopropionamide.

DOSAGE
Use concentrations are between 0.05 and 0.5% depending on the product to be protected and the environment

DBNPA is a desirable biocide because it is a fast acting, low cost material that exhibits efficacy against a broad spectrum of microorganisms

2,2-Dibromo-3-Nitrilopropionamide (DBNPA)
DBNPA or 2,2-dibromo-3-nitrilopropionamide is a quick-kill biocide that easily hydrolyzes under both acidic and alkaline conditions. It is preferred for its instability in water as it quickly kills and then quickly degrades to form a number of products, depending on the conditions, including ammonia, bromide ions, dibromoacetonitrile, and dibromoacetic acid.DBNPA acts similar to the typical halogen biocides.

DBNPA is used in a wide variety of applications. Some examples are in papermaking as a preservative in paper coatingand slurries. It is also used as slime control on papermachines, and as a biocide in hydraulic fracturing wells and in cooling water.

Their wide application in water treatment plants and paper, oil as well as oil and gas industries is an example of their popularity in the market

DBNPA is also used in the pulp, paper, oil, and gas industry .
DBNPA is a non-oxidative agent, rapidly degrading in alkaline aqueous solutions.
The organic water content as well as light enhance the hydrolysis and debromination of DBNPA into cyanoacetamide followed by degradation into cyanoacetic acid and malonic acid, that are non-toxic compounds.
This degradation pathway makes the use of DBNPA relatively environmentally friendly.
DBNPA is compatible with polyamide based membranes and shows high rejection rates for RO membranes.
The antimicrobial effect is due to the fast reaction between DBNPA and sulfur-containing organic molecules in microorganisms such as glutathione or cysteine.
The properties of microbial cell-surface components are irreversibly altered, interrupting transport of compounds across the membrane of the bacterial cell and inhibiting key biological processes of the bacteria

2, 2-Dibromo-3-Nitrilopropionamide is Compound with Slimicidal Activity

Non-oxidising biocides such as DBNPA are used across industry to control microbiological activity in a wide range of water systems, often in rotation with oxidising biocides.
Biocidal performance is concentration dependant, so it is essential to monitor the activity levels closely in any system to ensure microbiological control.
Our customers may prefer to use a DBNPA Kit to monitor the activity.

2,2-Dibromo-3-nitrilopropionamide (DBNPA) is a broad- spectrum biocide for controlling the growth of bacteria, fungi, yeasts, cyanobacteria and algae
The most common mode of application of DBNPA is as a liquid formulation.
Since DBNPA has poor solubility in water, these formulations typically contain as a carrier a mixture of water and an organic solvent, most often a glycol (for example, polyethylene glycol (PEG) , dipropylene glycol (DPG) and others) .
The concentration of the DBNPA in such liquid formulations is typically about 5-25%.

Alternatively, DBNPA is formulated as solid compacted products, available as granules or tablets

Another form of application of DBNPA is as an aqueous suspension.
Such suspensions are typically obtained with the aid of suspending agents.
Since DBNPA is stable in water only under acidic conditions, special suspending agents are required, which are stable at a pH below 5.
For example, . WO 2007/096885 discloses a 30-50% aqueous suspension of DBNPA having a pH in the range of 1 to 4, containing xantham gum as the proposed thixotropic suspending agent, which suggests a high viscosity for avoiding sedimentation in a static state, and a moderate viscosity when pumping the slurry.

Formula
C3H2Br2N2O
CAS No.   10222-01-2
EC No.   233-539-7
Synonyms   2,2-Dibromo-2-cyanoacetamide; DBNPA; 2,2-Dibromo-2-carbamoylacetonitrile; 2,2-Dibromo-3-nitrilopropionamide; 2,2-dibromo-2-cyano-ethanamide; Dibromocyanoacetamide; Dibromocyano acetic acid amide

IUPAC name
2,2-Dibromo-2-cyanoacetamide
2,2-Dibromo-3-nitrilopropionamide

Other names
Dibromocyano acetic acid amide
2,2-Dibromo-3-nitrilopropionamide

CAS Number: 10222-01-2

Identifiers
CAS Number
10222-01-2 check

EC Number: 233-539-7
2,2-dibromo-3-nitrilopropionamide

UN number 1759

Properties
Chemical formula: C3H2Br2N2O
Molar mass: 241.870 g·mol−1
Appearance: White, translucent crystals
Melting point: 122 to 125 °C

10222-01-2 [RN]
2,2-Dibrom-2-cyanacetamid [German] [ACD/IUPAC Name]
2,2-Dibromo-2-carbamoylacetonitrile
2,2-Dibromo-2-cyanoacetamide [ACD/IUPAC Name]
2,2-Dibromo-2-cyanoacétamide [French] [ACD/IUPAC Name]
2,2-Dibromo-3-nitrilopropionamide
233-539-7 [EINECS]
3-02-00-01641 [Beilstein]
3-02-00-01641 (Beilstein Handbook Reference) [Beilstein]
AB5956000
Acetamide, 2,2-dibromo-2-cyano- [ACD/Index Name]
Cyanodibromoacetamide
Dbnpa
dibromocyanoacetamide
MFCD00129791 [MDL number]
ZVXEECN [WLN]
[10222-01-2]
‘10222-01-2
2,2, Dibromo 3-Nitrilopropionamide
2,2-bis(bromanyl)-2-cyano-ethanamide
2,2-dibromo-2-cyano-acetamide
2,2-Dibromo-2-cyanoacetamide (DBNPA)
2,2-Dibromo-2-cyanoacetamide, 9CI
2,2-dibromo-2-cyano-ethanamide
2,2-Dibromo-3-Nitrilo propionamide (DBNPA)
2,2-Dibromo-3-Nitrilopropion Amide
2,2-Dibromo-3-nitrilo-propionamide
2,2-dibromo-3-nitrilopropionic acid amide
2-Cyano-2,2-dibromoacetamide
2-Cyano-2,2-dibromo-Acetamide
EINECS 233-539-7
FR-2220
Jsp000273
NCGC00164203-01
SBB008529
UNII:7N51QGL6MJ
UNII-7N51QGL6MJ
XD 7287L

2,2-DIBROMO-2-CYANOACETAMIDE
10222-01-2
Dibromocyanoacetamide
2,2-Dibromo-3-nitrilopropionamide
Dbnpa
Acetamide, 2,2-dibromo-2-cyano-
2-Cyano-2,2-dibromoacetamide
XD-7287l Antimicrobial
2,2-Dibromo-2-carbamoylacetonitrile
UNII-7N51QGL6MJ
Dibromocyano acetic acid amide
XD-1603
7N51QGL6MJ
Caswell No. 287AA
NSC 98283
HSDB 6982
Dibromonitrilopropionamide
XD 7287L
EINECS 233-539-7
EPA Pesticide Chemical Code 101801
BRN 1761192
2,2-dibromo-2-cyano-acetamide
Acetamide, 2-cyano-2,2-dibromo-
DBNP
3-02-00-01641 (Beilstein Handbook Reference)
Acetamide,2-dibromo-2-cyano-
ACMC-20980y
2-Cyano-2,2-dibromo-Acetamide
CHEMBL1878278
DTXSID5032361
NSC98283
ZINC1638458
2,2, Dibromo 3-Nitrilopropionamide
2,2-dibromo-3-nitrilopropion amide
Tox21_300089
2,2-Dibromo-2-cyanoacetamide, 9CI
2, 2-Dibromo-2-carbamoylacetonitrile
2,2-Dibromo-2-cyanoacetamide, 96%
AKOS015833850
2,2-bis(bromanyl)-2-cyano-ethanamide
2,2-Dibromo-3-Nitrilo propionamide (DBNPA)

DBNPA
Technical Grade 2.2-dibromo-3-nitrilopropionamide.
DBNPA is a Quick-kill biocide.
DBNPA controls bacteria, fungi and algae in industrial processes and water systems including: paper mills, industrial cooling water systems.
DBNPA controls slime-formation in air washer systems.

Use DBNPA safely. Always read the label and product information before use.

DBNPA It is understood in the membrane industry that thin film composite polyamide membranes have limited resistance to chlorine based oxidants.
Therefore, operators have relatively few options regarding chemicals which can be safely used to disinfect RO/NF systems and prevent biogrowth/biofouling.
One option is the chemical, 2,2-Dibromo-3-nitrilopropionamide (DBNPA), which is a fastacting, non-oxidizing biocide which is very effective at low concentrations in controlling the growth of aerobic bacteria, anaerobic bacteria, fungi and algae.
The chemical formula of DBNPA is: DBNPA is an advantageous disinfectant since it also quickly degrades to carbon dioxide, ammonia and bromide ion when in an aqueous environment.
This allows the effluent to be safely discharged even in sensitive water bodies.
It is degraded by reactions with water, nucleophiles, and UV light (rate is dependent on pH and temperature).
The approximate half-life is 24 hr @ pH 7, 2 hr @ pH 8, 15 min @ pH 9.
The vast majority of microorganisms that come into contact with it are killed within 5 to 10 minutes.

Product Forms
Most RO/NF chemical suppliers have a premixed private label version with varying solution concentrations of 5% to 20% or available as a white crystalline solid.
Recommended Usage for RO/NF Systems For slug dosing, the supplier recommends 10 – 30 ppm of active ingredient for 30 minutes to 3 hours every 5 days (for waters less prone to biological fouling).
Slug dosing can be performed during service operation, during a low pressure flush mode, or by a batch CIP (Clean-In-Place) system.

RO/NF permeate may need to be diverted to drain as operations dictate, though it is estimated that greater than 98% of the DBNPA is rejected by brackish water membranes and greater than 99.5% by seawater membranes.
For waters containing > 100 CFU/ml (or if you already have biofilm within the RO/NF system), suppliers recommend 30 ppm active ingredient for a full 3 hours.
During slug dosing, the permeate should be dumped to drain if product water is for a potable use.

If a biofilm is present, sanitization should be preceded by an alkaline cleaning.
For continuous dosing during service operation, between 0.5 to 2 ppm of active ingredient is recommended to maintain a biostatic environment. RO/NF permeate may need to be diverted to drain as operations dictate.
Continuous dosing can be significantly more expensive in terms of operating costs so the site situation will dictate if this is instituted.
DBNPA is deactivated by reducing agents, so a higher concentration of DBNPA will be required if residual reducing agents are present in the feed water.

For example, Sodium Bisulfite (SBS) will deactivate DBNPA.
If SBS is dosed during service or flushing operations, additional DBNPA will be required at a suggested dose rate of 1.0 to 1.3 ppm DBNPA per 1 ppm of SBS to account for deactivation.
Excess SBS can also be used to accelerate the deactivation of DBNPA in discharged waters.
Although DBNPA is non-oxidizing, it will give an ORP reading of about 400 mv when in the range of 0.5 – 3 ppm ( for comparison, 1 ppm chlorine typically gives an ORP reading of about 700 mv). For CIP use, 30 – 50 ppm of active ingredient for 1 hour would be recommended.
For heavy biofilms, it should be followed by an alkaline cleaning.
Test kits are available from the chemical suppliers to verify that DBNPA is at the desired concentration or has been completely rinsed from the system. Warnings
• DBNPA is corrosive to metals, so plastics are preferred for storage and metering pumps. This is not as much of a concern at the very low concentrations used in RO/NF systems.
• DBNPA has minimal toxicology concerns, but the supplier recommends that for potable water systems the permeate be dumped during slug-dosing.
Only off-line use of DBNPA is recommended for potable water systems.
• DBNPA is classified as a “weak sensitizer.” As when handling any chemical, reference the Material Data Safety Sheet (MSDS) for precautions and proper handling and storage.
• Although DBNPA is useful as a disinfectant, it should not be used for storage since it is not long-acting IMPORTANT: Users should review all technical product documents and talk to their supplier to ensure that they have the most recent and accurate information regarding precautions associated with the use of DBNPA.

Application of DBNPA dosage for biofouling control in spiral wound membrane systems

a b s t r a c t
Biocides may be used to control biofouling in spiral-wound reverse osmosis (RO) and nanofiltration (NF) systems.
The objective of this study was to investigate the effect of biocide 2,2-dibromo-3-nitrilopropionamide (DBNPA) dosage on biofouling control.
Preventive biofouling control was studied applying a continuous dosage of substrate (0.5 mg/L) and DBNPA (1 mg/L).
Curative biofouling control was studied on pre-grown biofilms, once again applying a continuous dosage of substrate (0.5 mg acetate C/L) and DBNPA (1 and 20 mg/L).
Biofouling studies were performed in membrane fouling simulators (MFSs) supplied with biodegradable substrate and DBNPA.
The pressure drop was monitored in time and at the end of the study, the accumulated biomass in MFS was quantified by adenosine triphosphate (ATP) and total organic carbon (TOC) analysis.
Continuous dosage of DBNPA (1 mg/L) prevented pressure drop increase and biofilm accumulation in the MFSs during a run time of 7 d, showing that biofouling can be managed by preventive DBNPA dosage.
For biofouled systems, continuous dosage of DBNPA (1 and 20 mg/L) inactivated the accumulated biomass but did not restore the original pressure drop and did not remove the accumulated inactive cells and extracellular polymeric substances (EPS), indicating DBNPA dosage is not suitable for curative biofouling control.

Keywords: Biofouling control; Biocide DBNPA; Membranes; Water treatment; Seawater desalination; Wastewater reuse

Chemical dosage to the feed water may enable biofouling control. Recently, an alternative for monochloramine 2,2-dibromo-3-nitrilopropionamide (DBNPA) has been applied in limited number of water treatment plants. DBNPA is also used in the pulp, paper, oil, and gas industry [15]. DBNPA is a non-oxidative agent, rapidly degrading in alkaline aqueous solutions [16]. The organic water content as well as light enhance the hydrolysis and debromination of DBNPA into cyanoacetamide followed by degradation into cyanoacetic acid and malonic acid, that are non-toxic compounds [17]. This degradation pathway makes the use of DBNPA relatively environmentally friendly. DBNPA is compatible with polyamide based membranes and shows high rejection rates for RO membranes [18]. The antimicrobial effect is due to the fast reaction between DBNPA and sulfur-containing organic molecules in microorganisms such as glutathione or cysteine [19–21]. The properties of microbial cell-surface components are irreversibly altered, interrupting transport of compounds across the membrane of the bacterial cell and inhibiting key biological processes of the bacteria [19,20,22]. To assess the anti-biofouling effect, on-line and off-line applications of the biocide have been studied on industrial scale RO installations with a 20 ppm DBNPA concentration in the feed water. Industrial case studies described by [18] indicate a preventive effect of the biocide, but many details were not given. Only very limited information on the suitability of DBNPA to control membrane biofouling under well-defined conditions is available. The objective of this study was to determine, under well-controlled conditions, the effect of biocide DBNPA dosage on biofouling control in membrane systems. Preventive and curative biofouling control strategies were investigated in a series of experiments with membrane fouling simulators operated in parallel, fed with feed water supplemented with DBNPA (1 or 20 mg/L) and a biodegradable substrate sodium acetate. A higher substrate concentration in feed water has shown to result in a faster and larger pressure drop increase and a higher accumulated amount of biomass [23–26]. In the studies acetate was dosed as substrate to enhance the biofouling rate. The pressure drop was monitored and autopsies were performed to quantify the accumulated material.

Continuous DBNPA dosage with a dose of 1 mg/L is a strategy to prevent or restrict biofouling.

Active Ingredients: 2,2-Dibromo-3-NitriloPropionamide (DBNPA) 98% min.assay.
Highly effective against a wide range of common water borne organisms with proven efficacy against Legionella.
2,2-Dibromo-3-NitriloPropionamide will control these organisms and help to control microbiological fouling.

2,2-Dibromo-3-NitriloPropionamide is designed for use in open cooling water systems, chilled water systems, process systems and other industrial water systems. DBNPA has proven efficacy against pathogenic microorganisms including Legionella, at levels required by the system, L8 (HS(G) 274), system water type, along with risk assessment data.

2,2-Dibromo-3-NitriloPropionamide degrades rapidly and naturally at increased pH & temperature levels and as such 2,2-Dibromo-3-NitriloPropionamide is the product of choice for systems operating under strict environmental and discharge regulations.

The ultimate degradation products are carbon dioxide, ammonia, & bromide ion. Increasing cooling water alkalinity presents a problem for most water treatment biocides. However, for 2,2-Dibromo-3-NitriloPropionamide even at higher pH values, rapid & effective microbial control is achieved before any significant degradation occurs. Ideal for quick, antimicrobial activity, but rapid degradation of the microbiocide for minimal environmental impact.

Recommended contact time for biological control is 4 hours minimum at the target residual.

HOW MUCH TO USE
2,2-Dibromo-3-NitriloPropionamide application rates for industrial recirculating cooling water systems will depend upon the conditions of the system prior to treatment initiation.

1.02g of 2,2-Dibromo-3-NitriloPropionamide will add 1ppm of DBNPA to 1000lt of system water.

Target Residual (ppm) x 1.02 x System Volume (m3) = dose required (g)

DBNPA shot dosed at 2-5ppm active is proven to control legionella in the planktonic phase with a contact time of 2-3 hours.
DBNPA shot dosed at 10-15ppm active is proven to control both planktonic and sessile legionella colonies with a contact time of 4-6 hours
DBNPA dosed to maintain a constant level of 1-2ppm active is proven to be effective at controlling legionella in the planktonic and sessile phase.
2,2-Dibromo-3-NitriloPropionamide can be tested and controlled by ATP, DBNPA biocide test kit or by measuring direct control through colony counts.

PROPERTIES
Appearance: Solid – white/yellow powder

Odour: characteristic/pungent

HANDLING AND STORAGE
2,2-Dibromo-3-NitriloPropionamide should be in a cool dry area.
Properly stored, the product will remain effective for 24 – 36 months.

PACKAGING
2,2-Dibromo-3-NitriloPropionamide is available in 2.5 kg jars (4 jars per case)

FEEDING
Feed 2,2-Dibromo-3-NitriloPropionamide using an Accepta board system.

2,2-Dibromo-3-NitriloPropionamide

DBNPA Biocide
DBNPA is a highly effective, environmentally friendly biocide.
DBNPA provides a quick kill while also quickly degrading in water.
The final end product is carbon dioxide and ammonium bromide.

Product formulations
DBNPA Liquid (5% and 20% solutions)
For applications in water treatment, pulp and paper, reverse osmosis, oil and gas, and metalworking fluid applications

DBNPA Chemistry
Chemical name: 2,2-dibromo-3-nitrilopropionamide

Compatibility with other water treatment chemicals and water conditions: DBNPA is compatible with other treatment chemicals with the exception of mercaptobenzothiazole.
It also is not compatible with ammonia or hydrogen sulfide-containing water. DBNPA maintains reliable control in systems running at acidic, neutral, or alkaline pH.

Degradation in water: DBNPA degrades quickly in aqueous environments.
At neutral pH, its half-life is about nine hours (Exner, Burk, and Kyriacou: Rates and Products of Decomposition of 2,2-dibromo-3-nitrilopropionamide, J. Agr. Food Chem., Vol. 21, 1973, pp. 838–842).
Continuous biocide release by the tablet maintains concentrations effective for control in the tower, while the biocide in the blowdown discharge degrades quickly.
So it’s easy to meet strict environmental regulations on tower discharge.

Is DBNPA an oxidizer?
DBNPA is not an oxidizing biocide and it is not a bromine release biocide. DBNPA does act similar to the typical halogen biocides.

2,2-Dibromo-3-nitrilopropionamide (DBNPA) chemical degradation in natural waters: Experimental evaluation and modeling of competitive pathways
Author links open overlay panelFred A.BlanchardStanley J.GonsiorDaniel L.Hopkins

An important environmental feature of 2,2-dibromo-3-nitrilopropionamide (DBNPA), the active ingredient in Dow’s Antimicrobials 7287 and 8536 is that the compound rapidly degrades in dilute aqueous solutions.
High performance liquid chromatography analyses of ppm-concentrations of DBNPA and its degradation products in laboratory tests of several natural water samples were used to follow the reactions involved.
A hydrolysis pathway leads to dibromoacetonitrile (DBAN) and other products.
The presence of organic material in the water leads to degradation by a second pathway in which monobromonitrilopropionamide (MBNPA) and several other degradation products are formed.
From the data, a computer simulation model of the reactions has been developed using DACSL (Dow Advanced Continuous Simulation Language).
The model describes quantitative relationships of DBNPA dosage and the natural water’s organic material content, as measured by total organic carbon (TOC), in the degradation pathways of DBNPA.
The model helps interpret the aquatic toxicity of the rapidly changing complex mixture produced during these degradations.
Simulations of the DBNPA treatment of cooling towers were compared to limited experimental data which indicated that most of the degradation occurred by the pathway which produced the less toxic products (MBNPA et seq. rather than DBAN et seq.)

Keywords
DBNPA
degradation model
aquatic toxicity
TOC
antimicrobial
dibromonitrilopropionamide
cooling tower

EPA
2,2-dibromo-3-nitrilopropionamide(DBNPA)
This Reregistration Eligibility Decision (RED) addresses pesticide uses of 2,2-dibromo-3- nitrilopropionamide (DBNPA).
Products containing this active ingredient are used to control microorganisms including algae, bacteria, and fungi in various industrial processes.
The Agency has completed its review of the target database for DBNPA and has concluded that most uses of DBNPA as labeled and used as specified in this Reregistration Eligibility Decision will not pose unreasonable risks or adverse effects to humans or the environment.
However, because the risk to non-target aquatic organisms from the discharge of industrial effluent containing DBNPA outweighs the potential benefits of the pesticidal use of DBNPA in single flow-through cooling towers, the Agency has concluded that this use is ineligible for reregistration.
The Agency intends to take appropriate regulatory steps to adequately address the potential risk of this use.
After evaluation of all available ecotoxicological and environmental data and subsequent consultation with the Agency’s Offices (Office of Water and the Office of Toxic Substances), it was determined that aquatic risk concerns for all currently registered uses except single flowthrough cooling systems may be adequately mitigated by secondary biological treatment of industrial effluent.
Ecotoxicological and environmental fate data indicate that DBNPA degrades rapidly by anaerobic and aerobic aquatic metabolism into less toxic degradates.

Secondary biological treatment is required for all aquatic industrial uses except,
1) waste water treatment systems,
2) secondary oil recovery systems, and
3) single flow-through cooling tower systems (ineligible for reregistration).

Biological treatment is not required for waste water treatment systems because biological degradation readily occurs in these systems.
Although secondary biological treatment is not feasible for secondary oil recovery systems, an evaluation of the secondary oil recovery use pattern as it relates to DBNPA sufficiently reduces the Agency’s concern with this use pattern.
However, aquatic risk concerns for the single flow-through cooling system use of DBNPA cannot be mitigated.
Single flow-through cooling systems represent a direct surface water discharge situation and a potential adverse risk to aquatic species remains.
Additionally, the Agency has a concern for the potential effect of DBNPA on human developmental toxicity.
In an oral developmental toxicity study in rabbits, DBNPA was observed to produce fetal structural alterations at a dose (30 mg/kg/day) which was not maternally toxic.
The NOEL for developmental effects was 10 mg/kg/day and the maternal NOEL was 30 mg/kg/day.
There is a potential for mixer/loader/applicator exposure from use.
Margin of Exposures (MOE) are acceptable (greater than 100) for all uses regulated by the EPA except one, that of the handler using an open pouring method to add DBNPA to cooling towers (MOE = 28).
The Agency is therefore requiring use of personal protective equipment for open pouring for recirculating cooling water tower uses.
The potential for post-application acute exposure is minimal.
A food tolerance has been established for DBNPA for food contact with food grade paper and paperboard (21 CFR 176.300).
The use of DBNPA for this purpose is regulated under the jurisdiction of the U.S. Food and Drug Administration.

Common Name: DBNPA
Chemical Name: 2,2-dibromo-3-nitrilopropionamide
Chemical Family: Dibromo-3-nitrilopropionamide
CAS Registry Number: 10222-01-2
OPP Chemical Code: 101801
Empirical Formula: C3H2Br2N2O
Molecular Weight: 242
Trade and Other Names: DBNPA
Slimicide 508
XD-7287L Antimicrobial
XD-1603
2,2-dibromo-2-carbamoylacetonitrile
2,2-dibromo-2-cyano-acetamide

Type of Pesticide:

DBNPA is an algicide, bactericide and fungicide (slime-forming algae,bacteria and fungi); preservative (additive); fungicide (mold and mildew).
Use Sites: AQUATIC NON-FOOD INDUSTRIAL:

< pulp, paper and paperboard mill water systems
< air washer water systems
< commercial/industrial water cooling systems (single flowthrough cooling tower systems and recirculating cooling tower systems): influent systems, flow through filters, cooling ponds, canals and lagoons
< evaporative condenser water systems
< secondary oil recovery injection water, underground flood water, non-marine underground flood water
< sewage systems
< heat exchanger water systems
< industrial auxiliary water systems
< laboratory equipment water baths
< industrial scrubbing systems

INDOOR NON-FOOD
< pasteurizer/warmer/cannery cooling water systems,brewery pasteurizers
< industrial adhesives, animal glues
< industrial and paper mill coatings
< metalworking cutting fluids
< oil recovery drilling muds, packer fluids and gypsum mud
< latex paints (in-can)
< paper/paper products
< resin/latex/polymer emulsions: emulsions, polymers and defoamers
< latex/oil/varnish paints (applied film)
< specialty industrial products (waxes, polishes and ink)
< wet-end additives/industrial (pigment slurries and sizing)

INDOOR FOOD
< food packaging (regulated by FDA)
Target Pests: Coliform bacteria; slime-forming and odor-causing algae, bacteria and fungi; yeasts; sulfide producing bacteria (enhanced oil recovery)

Aquatic non-food industrial:
Water treatment, water recirculating system treatment, water once-through system treatment.

Indoor non-food: Water treatment, water recirculating system treatment, industrial preservative treatment (added during manufacture), preservative treatment.

Indoor non-food
Preservative uses:
Industrial adhesives; Industrial coatings; Metalworking cutting fluids; Latex/oil/varnish paints (applied film);Paper/paper products; Specialty industrial products; Wetend additives /industrial (processing chemicals)
20 to 2000 ppm of active ingredient by weight

Industrial preservative uses:
Industrial adhesives; Industrial coatings;
Resin/latex/polymer emulsions; Metalworking cutting
fluids; Oil recovery drilling (muds/packer fluids); Latex paints (in-can); Latex/oil/varnish paints (applied film); Specialty industrial products; Wet-end additives/industrial (processing chemicals)
10 to 2000 ppm of active ingredient by weight

Regulatory History
Pesticide products containing DBNPA as an active ingredient were first registered in the United States in 1972 as a microbicide.
There are currently 44 products registered by the EPA to 27 companies containing DBNPA as an active ingredient.
There is also one Special Local Need, FIFRA 24(c) registration for this chemical’s use in Missouri to control bacteria in a specified industrial water system.

Chemical name 2,2-Dibromo-3-nitrilopropionamide

Chemical Structure: Color white to “off white” color
Physical State: crystalline solid
Odor: mild “medicinal antiseptic”
Melting point 123-126E C.
Boiling point decomposes at 190 C.
Density 2.375 at 21E C., 0.934-1.370 g/ml.

Solubility at 25E C.
Solvent Solubility gms/100ml
Acetone 35
Ethanol 25
Water 1.5

Octanol/Water
Partition Coefficient Kow 6.24 ±0.173 at pH 5.0
Kow 6.31 ±0.075 at pH 7.0
Kow 6.61 ±0.126 at pH 9.0
pH at 25C: 6.61 in 0.01% aqueous solution
Oxidizing or Reducing Reaction: Incompatible with bases, reducing substances and nucleophiles
Flammability: Cannot support combustion

Corrosion Characteristics: Corrosive to mild steel, iron and aluminum

Laboratory and field tests demonstrated that 2,2-dibromo-3-nitrilopropionamide was an effective slimicide for use in papermaking systems and cooling towers.
2,2-Dibromo-3-nitrilopropionamide was also effective as a bactericide for soluble oil emulsions.

The white, crystalline DBNPA has been stable for at least 4 years under laboratory storage conditions.
This conclusion is based upon no detectable change in appearance or biological activity during this storage period.
DBNPA dissolves in water to give a relatively stable solution in an acid pH range.
Its unusual solubility and stability in polyethylene glycol (average molecular weight, 200) make this glycol a preferred solvent.

Aqueous solutions hydrolyze under alkaline conditions, with the rate of decomposition increasing with the alkalinity.
However, the rate of hydrolysis is not fast enough to interfere with the antimicrobial activity of fresh, alkaline (pH 7 to 9.5) solutions.
Heat and ultraviolet and fluorescent light also cause aqueous solutions of DBNPA to degrade, as evidenced by the change of the antimicrobial end point as a given solution ages.
This decomposition has also been substantiated by chemical analysis.

Toxicological properties.
Animal tests, carried out in our toxicological laboratory, have indicated that DBNPA is moderately toxic.
The 50 % lethal dose (LD5) value ranges from 118 mg/kg of body weight for female guinea pigs to 235 mg/kg for male Sherman rats.
Eye-contact tests on laboratory animals indicate that DBNPA damaged the eye seriously enough to cause possible impairment of vision.
A single, short skin exposure to DBNPA should result in no significant irritation.
A single prolonged or frequently repeated skin exposure, however, may result in irritation, even a burn, depending on the severity of the exposure.
Based on animal tests, this material is not likely to be absorbed through the skin in acutely toxic amounts (5).
The acute fish toxicity of fresh and aged solutions of DBNPA has been determined for fathead minnows, Pimephales promelas Rafinesque, using dechlorinated Lake Huron water at 50 F and 72 hr of exposure (2).
A fresh solution killed the minnows above 1 ug/ml, but parallel studies of solutions aged at pH 9 did not kill at the highest concentration tested, 100 ug/ml.

TABLE 1. Solubility of 2,2-dibromo-3- nitrilopropionamide in common solvents
Solvent rams/ Temp- Solvent 100 g of (C)
solvent
Acetone …………………… 35 25
Benzene …………………… < 1.0 20
Dimethyl formamide …………. 120 25
Ethanol …………………… 25 20
Polyethylene glycol (mol wt, 200) . . 120 25
Water …………………… 1.5 25

TABLE 2. Antimicrobial activity of 2,2-dibromo-3-nitrilopropionamide

Enterobacter aerogenes, ATCC 13048 ….. 100
Bacillus subtilis, ATCC 8473 …………. 100
Desulfovibrio desulfuricans, A.P.I. RP 38 . 10
Escherichia coli, ATCC 11229 ………… 100
Pseudomonas aeruginosa, ATCC 8709.. .100
Pseudomonas aeruginosa, USDA, PRD 10 100
Salmonella typhosa, ATCC 6539 ……… 100
Staphylococcus aureus, ATCC 6538 ……. 250
Aspergillus terreus, ATCC 10690 ……… 100
Candida albicans, ATCC 10231 ………. 100
Candida pelliculosa, ATCC 2149 ……… 100
Pullularia pullulans, ATCC 9348 ……… 100
Rhizopus nigricans, ATCC 6227A …….. 10
a The pH of bacterial medium was 7.0 to 7.2, and that of the fungal medium was 5.0 to 5.5.

In vitro microbial inhibition tests.
Appropriate volumes of stock acetone solutions of the test compounds were added to tubes of melted, sterile nutrient agar (for bacteria) and malt-yeast extract-agar (for fungi) to give the desired final concentration.
After being mixed into the media, individual samples were poured into sterile, disposable, polystyrene plates and allowed to harden.
Duplicate plates were inoculated with bacteria and fungi in separate operations with an Accu-Drop (The Sylvania Co., Orange, N.J.) dispensing apparatus.
Approximately 0.02 ml of each culture was simultaneously dispensed in uniform droplets on the agar surface. Broth cultures (48 hr) of bacteria were used.
Fungal inocula were prepared by harvesting the spores from mature agar slants by washing with sterile water, followed by filtration through sterile gauze.
Inoculated bacterial plates were incubated for a minimum of 72 hr at 30 C, whereas the fungal plates were incubated for at least 5 days at 30 C.
(The plates were observed after 2 days for growth of Rhizopus nigricans, and, if growth had occurred, that portion of the agar was excised with a sterile spatula to prevent overgrowth of the entire plate.)
Lack of visible growth at the end of these periods was recorded as inhibition of the organism at the concentration of compound under test.
The organisms tested are listed in Table 2 and represent a spectrum of interest in industrial preservation.
Inhibition of sulfate-reducing bacteria.
Inhibition of Desulfovibrio desulfuricans was determined by the procedure recommended by the American Petroleum Institute (1).
Growth of sulfate reducers in the bottles was indicated by an intense blackening of the medium.
Slimicidal activity in simulated pulp suspensions.
A test substrate of 0.5% ground wood pulp at pH 5.5 and at pH 8 was used to determine the slimicidal activity.
The inoculum consisted of a pooled mixture of organisms implicated in causing paper mill slime.
One-day-old broth cultures of Candida pelliculosa and Enterobacter aerogenes were used.
In the case of Bacillus subtilis, the broth culture was 5 days old to allow for spore formation.
Spores of the two fungi, Aspergillus terreus and Penicillium chrysogenum, were harvested with cotton swabs from well sporulated malt-yeast-agar slants, by using 10 ml of sterile saline per slant.
The final inoculum was prepared by adding 1.0 ml from each of the above sources to 95 ml of physiological saline.
A 1.0-ml inoculum of this mixture was added to 100 ml of pulp suspension to which the test compound had been added.
After exposure periods of 3, 24, and 48 hr, portions were subcultured into suitable media to determine the biocidal concentration of the test compound.
The subcultures were incubated at 30 C for at least 5 days.
Slimicidal activity in headbox pulp suspensions.
DBNPA was tested as the solid material (98% active) and as a solution with the solvent, polyethylene glycol, with average molecular weight of 200. Headbox stocks from two mills were used.
One mill was producing a wide variety of paper used in TABLE 1.

Slimicidal activity in paper mill trials.
A solution of DBNPA was added at several points in the paper-making operation, as recommended by personnel at the particular mill.
Slime control was determined by periodic plate counts and by inspection of the critical surfaces of the paper-making equipment, combined with the judgment of experienced operators.
Slimicidal activity in cooling water trials.
DBNPA was evaluated as a slimicide in a slug treatment for cooling tower water.
The water circulated from a large, concrete holding pond with a capacity of 882,000 liteis.
The makeup water (95 liters/min) came from a nearby river.
Control bacterial counts were established for the pond water, and DBNPA was then added as a solid powder near the circulating pump.
Subsequent bacterial counts gave an indication of the effect of DBNPA in the system.
In a second field trial, DBNPA was tested with both continuous and intermittent addition.
The cooling tower system had a capacity of 727,000 liters with a water makeup rate of 950 liters/min.
The cooling tower was located in Louisiana, and the test was started in November, 1970, and continued through November, 1971.
A polyglycol solution of DBNPA was added to the cooling tower basin with a metering pump.
Slimicidal control was determined by periodic plate counts, by inspection of the cooling tower fill, and by feel for slime formation, as judged by an experienced operator.
Soluble oil preservation.
DBNPA was added to commercial oil formulations before dilution with water (1 part oil to 40 parts water, as recommended by the manufacturers).
An inoculum was prepared by adding 10 ml of 24-hr broth cultures of E. Aerogenes and Pseudomonas oleovorans (two organisms commonly cited in contaminated soluble oils) to 80 ml of the diluted oil emulsion under test.
Control bacterial counts were in the order of 108 organisms per ml.
The oil emulsions were inoculated (5.0 ml of inoculum per 95 ml of emulsion) and tested for viability after 24 hr of exposure by swabbing samples onto brain heart infusion agar with a cotton applicator.

Soluble oil preservation.
The effectiveness of DBNPA varied depending upon the nature of the soluble emulsion tested.
The oils tested represented samples from five major producers of soluble or cutting oils.
DBNPA killed the natural inoculum in these emulsions in a range of 25 to 100 Ag/ml within a period of 24 hr.
Since most soluble oil formulations have an alkaline pH, the hydrolysis of DBNPA limits its extended activity in these systems.
DISCUSSION
Studies of the rate of kill show that DBNPA is bactericidal and fungicidal over a moderate range of concentrations in 1 to 3 hr.
This rate is adequate for controlling bacterial and fungal growth in paper mill and cooling tower systems.
However, the rate is too slow for DBNPA to be used as a disinfectant.
The breakdown of DBNPA in the pH range from 7 to 9.5 may limit its use in single-dose applications where extended antimicrobial activity is mandatory.
For example, a single addition can be used to effect bacterial reduction in soluble oil emulsions.
However, these emulsions usually have an alkaline pH, and DBNPA may fail to protect against repeated bacterial insults within a period of 3 or 4 days.

AQUCAR MEM 20
Water Treatment Microbiocide
2,2-Dibromo-3-nitrilopropionamide (DBNPA)
CAS Reg. No. 10222-01-2
EINECS No. 2335397
Non-Oxidizing Biocide to Reduce Biological Fouling in Reverse Osmosis (RO) Systems for Industrial Water Production and off-line cleaning of RO membranes producing potable and municipal water.
Biofouling of RO membranes is a common problem for many membrane filtration systems that source water from open ocean intakes, sea water wells, brackish river water and other surface waters that contain naturally occurring organic matter.
The limiting factor to biofouling control is the incompatibility of the polyamide thin-film composite RO membrane to chlorine exposure, as well as exposure to other oxidizing chemicals commonly used for process water disinfection.
DBNPA may be used to control bacteria and reduce biofouling in various membrane system types (reverse osmosis, ultra-filtration, nano-filtration, and microfiltration) used for industrial water processing.
Acceptable industrial applications include reverse osmosis systems for the production of boiler make-up water for electric power production, electronic component rinsing, and in chemical manufacturing industry.
DBNPA can also be used for off-line cleaning of RO membranes producing potable and municipal water.
AQUCAR MEM 20 Water Treatment Microbiocide is for use in RO systems in the industrial market and for off-line cleaning of RO membranes producing potable and municipal water.
It is important to note that AQUCAR MEM 20 Water Treatment Microbiocide is NOT approved for on-line use in RO systems that produce potable and municipal water.

Note: Due to regional differences, 20% DBNPA for industrial RO systems is approved and marketed in Europe under the product name of AQUCAR DB 20 Water Treatment Microbiocide.
In other approved regions of the world it is marketed under the name AQUCAR MEM 20 Water Treatment Microbiocide. Photo courtesy of Inalsa

The following are typical properties of AQUCAR MEM 20 Water Treatment Microbiocide; they are not to be considered product specifications.
Active ingredient (%): 20% by weight
Inert ingredients: Polyethylene glycol and water
Color: Colorless to brown
Appearance: Liquid
Odor: Odorless to mild
Freezing point:< -50°C (per ASTM D-97)
Boiling point: > 70°C for solution, but active ingredient decomposes prior to boiling
Freeze-Thaw stability: Passed 7 cycles at -15° to 20°C
Specific gravity: 1.20-1.30 g/mL @ 23°C
Vapor pressure: 18.9 mmHg @ 25°C

AQUCAR MEM 20 Water Treatment Microbiocide is an aqueous formulation containing 20% (w/w) concentration of DBNPA (2,2-Dibromo-3-nitrilopropionamide).
When properly applied to the RO feed water systems, AQUCAR MEM 20 Water Treatment Microbiocide is:
• Fast-acting, non-oxidizing biocide
• Effective against a broad spectrum of microorganisms
• Completely miscible with water upon dispersion at end-use levels

DBNPA, the active ingredient in AQUCAR MEM 20 Water Treatment Microbiocide, has proven efficacy at low concentrations against bacteria, fungi, yeast, cyanobacteria (also referred to as blue-green algae) and true algae.
The DBNPA molecule will function immediately upon introduction into the feed water and antimicrobial control is rapidly achieved if properly dosed.
Structure Physical Properties Features and Benefits Photo courtesy of SUT Seraya MW = 242 Br Br N O NH2

Because of its extremely rapid kill, proliferating microbes and their biofilm formation on RO membranes and in feed channel spacers is reduced significantly.
The low persistence of DBNPA minimizes safety and environmental concerns with water discharge and atmospheric emissions.
When added to an RO system, DBNPA is rejected by the thin-film composite membrane layer, and at use dilution, shows excellent compatibility with all materials of construction of the RO membrane module.
DBNPA has been used with great success in industrial water applications such as boiler make-up water for electric power generation, electronic component washing, in electroplating industry and also in chemical industry for polymer solutions.
DBNPA can be used for off-line cleaning of RO membranes producing potable and municipal water as long as the system is rinsed completely to remove AQUCAR MEM 20 Water Treatment Microbiocide prior to using the elements for potable and municipal water production.
Biofouling of the RO membranes can involve a variety of added expenses that contribute to the total cost in producing water – increased energy to drive the high-pressure feed water pumps, chemicals and waste disposal for RO element cleaning, new RO element installation, penalties for lost production, contract laboratory assistance and technical consultation, and increased addition of pretreatment chemicals.
AQUCAR MEM 20 Water Treatment Microbiocide offers an opportunity to reduce and/or eliminate many of these added cost items.

On-line Application for RO Membranes Producing Water for Industrial Uses
AQUCAR MEM 20 Water Treatment Microbiocide may be added to the RO feed water at a rate of 1 to 100 ppm based on the feed water flow rate (0.1 to 10 fl. oz./min. per 1000 gallons/min. feed water, or 0.8 to 80 mL/min. per cubic meter/min. of feed water).
Apply product to the service cycle feed water on a regular basis using an addition cycle of at least 30 minutes.
The frequency of addition may be daily or as necessary in order to maintain RO productivity performance. For highly fouled systems, a 100 ppm dosage should be applied each day for several hours until the system performance has recovered.
Note: In The Netherlands, Antimicrobial 7287 is approved for on-line cleaning at 2.5 to 50 mL per 1000 liters feed water.
Dosing is maintained until the system is under control.
Do not add AQUCAR MEM 20 Water Treatment Microbiocide in the presence of sodium bisulfite or other reducing agents which are commonly added to the feed water of the membrane system.
Addition of any reducing agents must be suspended at least 15 minutes prior to the addition of the product in order to avoid neutralization and deactivation of the active ingredient.
Off-line Cleaning of RO Membranes Producing Water for Industrial Uses AQUCAR MEM 20 Water Treatment Microbiocide may be added to the feed tank used for an off-line cleaning procedure.
Addition should be at a rate of 20 to 200 ppm based on the total amount of solution in the feed tank (2 to 20 fl. oz. per 1000 gallons, or 16 to 160 mL per cubic meter).
Following the complete transfer of feed solution, re-circulate or soak for 1 to 3 hours to ensure sufficient contact for all RO membrane modules with the DBNPA solution.
Frequency of addition should be every 5 days or as needed. Dosage Requirements

Note: In The Netherlands, Antimicrobial 7287 is approved for off-line cleaning (shock dosing) at 25 to 250 mL per 1000 liters feed water, 1-3 times per week.
Repeat until the system is under control.
Add AQUCAR MEM 20 Water Treatment Microbiocide separately to the feed tank system.
Do not mix with other chemical additives as this may result in rapid decomposition of the product due to the high pH of many additive formulas.
It is important to thoroughly rinse the feed tank system so it is free of any high pH chemicals prior to introducing AQUCAR MEM 20 Water Treatment Microbiocide.

Off-line Cleaning of RO Membrane Systems Producing Potable and Municipal Water

AQUCAR MEM 20 Water Treatment Microbiocide can be added to the feed tank used for an off-line chemical cleaning procedure.
Addition should be at a rate of 20 to 200 ppm based on the total amount of solution in the feed tank.
Following the complete transfer of feed solution, re-circulate or soak for 1 to 3 hours to ensure sufficient contact of all RO membrane modules with the DBNPA solution. Frequency of cleaning should be based on extent of fouling or as needed.
A moderately biofouled system could be cleaned once every week.
Note: The RO system should be completely rinsed with permeate quality water until concentration of residual DBNPA in final rinse water is below 40 ppb when measured by N, N-Diethyl-p-phenylenediamine (DPD) colormetric test method.
Due to regional differences in regulatory requirements, it is the responsibility of the user to confirm in their respective region that all regulatory approvals are obtained prior to use of AQUCAR MEM 20 Water Treatment Microbiocide in off-line cleaning of RO systems producing potable and municipal water.
Note: Add AQUCAR MEM 20 Water Treatment Microbiocide separately to the feed tank system.
Do not mix with other chemical additives as this may result in rapid decomposition of the product due to the high pH of many additive formulas.
Do not use heated water with product in the feed tank for cleaning RO membranes producing potable and municipal water as this may degrade the biocide.
It is important to thoroughly rinse the feed tank system so it is free of any high pH chemicals prior to introducing AQUCAR MEM 20 Water Treatment Microbiocide.
Equally important to ensuring a reliable, accurate delivery of AQUCAR MEM 20 Water Treatment Microbiocide is a successful tie-in to the process logic controller to suspend the addition of sodium bisulfite and/or any other reducing agents used for feed water pretreatment.
It is imperative to initiate this step at least 15 minutes prior to the addition of the product.
Failure to coordinate the timed addition of AQUCAR MEM 20 Water Treatment Microbiocide with the stoppage of sodium bisulfite will result in the deactivation of the DBNPA molecule.
DBNPA offers an advantageous combination of quick kill properties followed by fast chemical degradation, including hydrolysis.
The dominant degradation pathway at use conditions invloves reactions with nucleophilic substances or organic material invariably found in water.
Nucleophilic degradation forms cyanoacetamide.
When the disposal of concentrate involves the release to large open waterways, additional degradation will occur via exposure to UV-radiation.
When sufficiently diluted, DBNPA and its degradation products become biodegradable.
The ultimate degradation products formed from both chemical and biodegradation processes of DBNPA include ammonia, carbon dioxide, and bromide ions.
Therefore, meeting the local environmental regulations for the permitted discharge of the Environmental Advantages Environmentally Friendly Disposal of Brine reject stream should not be affected with DBNPA use.
However, compliance with local environmental regulations is the responsibility of the end-user.
Note: Reverse Osmosis (RO) concentrate streams should not be discharged to lakes, streams, ponds, estuaries, oceans or other waters unless in accordance with the local regulatory authorities.
Discharge of RO concentrate streams to sewer systems may require approval of the local sewer treatment plant authority.
AQUCAR MEM 20 Water Treatment Microbiocide is available in different size drums, pails and IBC totes.

Use Instructions for Various RO Membrane Systems
AQUCAR MEM 20 Water Treatment Microbiocide should not be used for On-line Application for RO systems producing potable and municipal water.

1. AQUCAR MEM 20 Water Treatment Microbiocide may be used for on-line, service cycle addition of all membrane systems (microfiltration, ultra-filtration, and nano-filtration) that are used to pre-treat the feed water to either a BW or SW membrane RO membrane system that produces industrial water.

2. AQUCAR MEM 20 Water Treatment Microbiocide may be used for on-line, service cycle addition in any RO systems producing industrial water.
It can be used for seawater (SW) or brackish water (BW) membrane type.
The product can be used continuously or on an intermittent usage basis as required to maintain the performance of RO membranes.

3. AQUCAR MEM 20 Water Treatment Microbiocide may be used for off-line addition as part of a chemical clean-in-place (CIP) treatment in RO and NF-type membrane systems producing water for industrial applications.
4. AQUCAR MEM 20 Water Treatment Microbiocide may be used for off-line cleaning of RO membrane systems producing potable and municipal water as long as the membranes are rinsed completely to remove residual product prior to potable and municipal water production.
Note: Do not add AQUCAR MEM 20 Water Treatment Microbiocide in the presence of sodium bisulfite or other reducing agents commonly added to the feed water of the RO systems.
The addition of any reducing agents must be suspended at least 15 minutes prior to the addition of product in order to avoid neutralization and deactivation of the active ingredient.
Note: Add AQUCAR MEM 20 Water Treatment Microbiocide separately to the feed tank system.
Do not mix with other chemical additives as this may result in rapid decomposition of the product due to the high pH of many additive formulations.

Use of DBNPA to control biofouling in RO systems
Ute Bertheas,Katariina Majamaa,Antonio Arzu &Ralph Pahnke
Pages 175-178 | Received 29 Sep 2008, Accepted 12 Feb 2009, Published online: 03 Aug 2012

This paper discusses the use of the non-oxidative biocide 2,2-dibromo-3-nitrilopropionamide (DBNPA) to minimize and/or eliminate problems due to biofouling accumulation and to ensure long-term performance of a RO system.
DBNPA is a suitable biocide due to its compatibility with reverse osmosis (RO) membranes.
Our aim is to present a better understanding of DBNPA, its rejection by common RO membrane types and the environmental chemistry concepts for residual DBNPA and its by-products in the outlet concentrate stream.
The application areas covered are industrial water and off-line drinking water systems.
Examples of field studies conducted on fullscale RO systems that use DBNPA will be shown.
Also discussed are the data obtained from the analysis that was carried out to determine the degradation of DBNPA in the RO feed and outlet stream.
The benefits of using DBNPA for biofouling prevention include reducing the required feed pressure and the cleaning frequency of the RO system.
Other benefits are reduced cleaning chemical costs, reduced downtime of the plant and reduced time of the operators.
This results in increased output of the plant and reduced operating expenses of the RO operation.

Keywords: RO systems
Biofouling
Biocide
DBNPA
Operating cost

Applications of 2,2-dibromo-3-nitrilopropionamide (DBNPA), a non-traditional antimicrobial agent, in metalworking-fluid production and use

During the normal treatment regimen, DBNPA is added directly to the water before it enters either the recirculating or once-through cooling system.
In recirculating systems, cooling water is passed through the system several times before it is discharged.
After each pass, heat is removed from the water.
In a once-through system, the cooling water is passed through the cooling system only once before entering the waste stream.
Additional treatment of the effluent may or may not occur before final discharge into the receiving water body.

2,2-Dibromo-3-nitrilopropionamide (DBNPA) has been documented as a useful antimicrobial agent in a number of industrial applications, due to its rapid rate of kill at relatively low use-concentrations, broad spectrum of antimicrobial activity, chemical non-persistence, and low environmental impact. It is available commercially as a 20% active solution in a water/polyethylene glycol blend. A discussion on the use of a non-oxidizing, fast-acting antimicrobial agent with a short chemical half-life, in various aspects of metalworking-fluid production and utilization, presented at the 59th STLE Annual Meeting (Toronto, Ontario, Canada 5/17-20/2004), covers lubricant degradation/stability-microbial; indirect food-contact approvals for DBNPA; decomposition pathways; microbiology; DBNPA as a preservative enhancer; efficacy of DBNPA; and methods of addition of DBNPA to water-based systems

DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are formulations containing 20% and 5%, respectively, of the active ingredient 2,2-dibromo-3-nitrilopropionamide, commonly referred to as DBNPA. Both products provide broad-spectrum control of bacteria, fungi, yeast, cyanobacteria (blue- green algae) and the true algae. DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are fast-acting biocides. Equally important, DOW Antimicrobial 7287 and DOW Antimicrobial 8536 decompose rapidly in aquatic environments, and are environmentally safe. DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are effective at low con- centrations and are completely compatible with standard chlorine treatment, providing synergistic control of microorganisms. Because DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are characterized by extremely rapid kill, proliferating microbes and their attendant slime problems are quickly reduced. Systems run better, with a higher efficiency, and at a lower cost. In fact, when an effective non-oxidizing biocide is required, none can match the total performance package offered by DOWAntimicrobial 7287 and DOW Antimicrobial 8536. Its fast action gives results quickly. You also get control of slime and algae. Yet the low persistency of DBNPA mini- mizes safety and environmental concerns with water discharge and atmospheric emissions. What happens when you treat systems with DOW Antimicrobials 7287 and 8536? DOW Antimicrobials 7287 and 8536 are completely miscible with water and easily dispersed upon introduction into your system. Microorganisms that come into contact with these antimicrobials are rapidly killed by a mechanism that appears to involve reaction with the protein fraction of the cell membrane and inactivation of enzyme systems. The vast majority of microorganisms are killed within five to ten minute

At the time of introduction, DOW Antimicrobials 7287 and 3536 begin to degrade. Ultimately, only carbon dioxide, ammonia, and bromide ion remain as end products. The entire process could take place with a half-life of less than one-half hour, depending on system conditions. But since effective microbial control is achieved before degradation, the ultimate effect is virtually ideal. Almost instantaneous antimicrobial activity combines with rapid chemical breakdown to present one of the most cost-effective ways of eliminating microbiological contamination with a minimum of environmental concern. DOW Antimicrobials 7287 and 8536 make short work of bacteria, fungi, yeast, and algae DOW DBNPA formulations are broadspectrum antimicrobials that quickly control fungi, yeast, bacteria, and algae. They are also effective against deleterious bacteria, including the etiological agent of Legionnaire’s Disease (Legionella pneumophila). Mortality rates against specific bacteria are given in Table 1, algistatic and algicidal properties are listed in Table 2, and effects on sulfate-reducing and heterotrophic bacteria are given in Table 3.

Recirculating water systems are com- monly contaminated with fungal and bacterial organisms, and occasionally with algae. In addition, their spores and reproductive cells are continuously present in the air, so the likelihood of repeated innoculation is extremely high from a biological standpoint. With their extremely fast killing action, DOWAntimicrobials 7287 and 8536 effectively control entering microorganisms before they can create problems. Because most microorganisms are killed very soon after exposure, there usually isn’t time for daughter generations to develop. Fast kill means first generation kill, which goes a long way toward preventing adaptation to the biocide or defense through secre- tion of biofilm. Kill rate outpaces degradation rate DOW DBNPA typically yields a 99.999 percent kill before it degrades sufficiently to lose effectiveness. Figure 1 shows the degrada- tion profile of DOW DBNPA for various tem- perature and pH combinations. At neutral pH and normal system operating temperatures, DOW DBNPA exhibits a half-life of about nine hours. As pH increases, the rate of degradation of DOW DBNPA increases, but virtually complete microbial kill is achieved well before significant degradation occurs. As shown in Figure 2, DOW DBNPA easily achieves 99.999% kill in under three hours even in alkaline systems.

Compatible and synergistic with chlorine treatment DOW Antimicrobial 7287 and DOW Antimicrobial 8536 provide excellent results in co-treatment programs with chlorine. Neither substance reacts with, degrades, or inhibits the antimicrobial activity of the other. In combined treatment programs in larger systems, DOW DBNPA antimicrobials help control a broader variety of microorganisms than chlorine treatment alone.

DOW DBNPA and control of Legionella pneumophila Since the identification of Legionella pneumophila as the etiologic agent of “Legionnaire’s Disease,” the U.S. Public Health Service Center for Disease Control (CDC) has recommended that cooling towers and evaporative condensers be maintained effectively in order to minimize the possibility of these systems serving as routes of transmission of the disease. DOW Antimicrobial 7287 (20 percent DBNPA) has been tested in the laboratory against L. pneumophila. The CDC published interim results of a laboratory study on the efficacy of six biocides against L. pneumophila in the June 22, 1979 Morbidity and Mortality Weekly Report. Dow Antimicrobial 7287 was effective in preventing recovery of the target organism from the test water. The Department of Biology at Memphis State University has also evaluated DOW Antimicrobial 7287 against L. pneumophila. In an uncompromised environment used in their laboratory procedure (0.85 percent saline), DOW Antimicrobial 7287 gave complete inhibition of L. pneumophila at 20 ppm and 2-hour exposure (Developments in Industrial Microbiology, Volume 21).
However, the ability of this formulation to control the growth of or inactivate Legionnaire’s Disease causing bacteria in operating water cooling

DOW DBNPA antimicrobials minimize environmental concerns Perhaps most important, DOW Antimicrobials 7287 and 8536 offer an unsurpassed environmental package, making it far easier for papermakers to conform to the increasingly strict environmental regulations governing their industry. To begin with, DOW DBNPA antimi- crobials are used in low concentrations. And unlike other mill slimicides, they exhibit fast degradation to carbon dioxide, ammonia, and bromide ion — all of which are considered innocuous in the environment at the low levels encountered. Meets FDA requirements Both DOW Antimicrobial 7287 and DOW Antimicrobial 8536 meet the require- ments of the Food and Drug Administration (FDA) for use as a slimicide in the manufac- ture of paper and paperboard intended to contact food when used at a maximum level of 0.1 lb 2,2-dibromo-3-nitrilopropionamide/ton of dry weight fiber, per 21 CFR 176.300 (formerly under 2I CFR 121.2505). Fast kill minimizes quality problems DOW Antimicrobials 7287 and 8536 provide exceptionally fast microbial kill rates — faster than virtually any other slimicide.
When the first signs of microbial contamination (pinholes, fisheyes) appear in finished paper, DOW Antimicrobials 7287 and 8536 can be added to the pulpstock to arrest a minor contamination problem before it becomes more serious.

Recommended method of addition You can feed either product, DOW Antimicrobial 7287 or DOW Antimicrobial 8536, with a metering pump at any point where uniform mixing can be attained. Please consult Section III, “Corrosivity,” for suggestions concerning equipment. Typical addition points are the beaters, jordan inlet or dis- charge, broke chests, furnish chests, save-alls, and/or white-water tanks. In addition, DOW Antimicrobial 7287 or DOW Antimicrobial 8536 can be added prior to contaminated areas in the system. Both slimicide products can be added continu- ously or periodically, with adjustments in the intervals between additions and dose levels dependent on visual inspections, microbiological analyses, and/or experienced observations of a water treatment representative. Treatment levels For the control of bacterial, fungal, and yeast growth in pulp, paper, and paperboard mills, add DOW Antimicrobial 7287 or DOW Antimicrobial 8536 at the rates given in Table 6 or Table 7.

The use of DOW Antimicrobials 7287 and 8536 in once-through cooling systems as part of a total water management program can effectively control microbial contamination and prevent the problems associated with these growths. DOWAntimicrobial 7287 and DOWAntimicrobial 8536 are EPA-registered for once-through systems DOW Antimicrobials 7287 and 8536 are two of only a few biocides with environmental properties allowing them to be registered with the EPA for once-through cooling systems. Their rapid degradation after microbial control is the key. Discharge of effluent water containing DOWAntimicrobials 7287 and 8536 into public water is permissible if done in accordance with an NPDES permit.

Synergistic performance with chlorine As with recirculating cooling systems, chlorine and DOW DBNPA are not only compatible in once-through cooling systems, but exhibit a strong synergistic effect and more rapid kill rates. Figure 3 on page 8 shows how powerful this synergism can be in neutral pH systems. Recommended method of addition Add the DOW DBNPA formulations to the heat-exchanger inlet water, based on the flow rate through the system, or before any other contaminated area. Addition should be made with a metering pump; it may be intermittent or continuous depending on the severity of contamination and the retention time in the system. Because cooling water passes through the heat-exchange surfaces of a once-through system on a one-time basis, slug feeding of a biocide to the inlet water would generally not be practical or effective. Control should be based on visual inspection, microbiological analyses, or the experienced observations of a water treatment representative. Treatment levels For the control of bacterial, fungal, and algal growth in once-through cooling systems, add DOW Antimicrobial 7287 or DOW Antimicrobial 8536 at the rates given in Table 8 or Table 9.

Recommended method of addition DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are best added to the air washer sump with the use of a metering pump.
These antimicrobials can be added on a continuous basis or intermittently, as necessary to maintain control.
Control should be based on visual inspection, microbiological analyses, or the experienced observation of a water treatment representative. Treatment levels For the control of bacteria and fungi in industrial air washer systems, add DOW Antimicrobial 7287 or DOW Antimicrobial 8536 at the rates given in Table 10 or Table 11. From the standpoint of economics and worker comfort, it is important to avoid exceeding the maximum recommended dosages given here. Moderate overtreatment may cause the formation of unpleasant odors in the workplace, while severe overtreatment may cause lachrymation.

DOW Antimicrobials 7287 and 8536 will kill microorganisms in injection water for subsurface enhanced oil recovery. DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are registered with the EPA for use in the control of slime-forming bacteria, sulfide-producing bacteria, yeasts, and fungi in oilfield water, polymer or micellar floods, water-disposal systems, and other oilfield water systems. Special note on sulfate-reducing bacteria When tested according to the test method of the American Petroleum Institute (API) RP-38, “Recommended Practice for Analysis of Subsurface Injection Water,”
10 ppm DBNPA provides effective control of Desulfovibrio desulfuricans. However, DOW DBNPA can be deactivated chemically in the presence of strong reducing agents such as hydrogen sulfide (H2S) — and to a much lesser extent by residual oxygen scavengers such as sodium bisulfite and ammonium bisulfite. So while DOW DBNPA will kill sulfate-reducing bacte- ria if they have not yet formed H2S, its antimi- crobial performance will be severely restricted or eliminated if the bacteria have already pro- duced H2S. Recommended methods of addition For microbial control in oilfield water, add DOW Antimicrobial 7287 or DOW Antimicrobial 8536 with a metering pump either continuously or intermittently. Additions may be made at the free water knockouts, before or after the injection pumps and injection well headers. Recommended treatment levels For controlling slime-forming bacteria, sulfide-producing bacteria, yeasts, and fungi in oilfield water, polymer or micellar floods, or other oilfield water systems, add either DOW Antimicrobial 7287 or DOW Antimicrobial 8536 at the rates given in Table 12 or Table 13.

Use with Biopolymers DOW Antimicrobial 7287 has been found to be effective in controlling bacteria, yeast, and fungi in aqueous solutions of biopolymer used in flooding operations. Add 15-80 ppm of DOW Antimicrobial 7287 (1.2- 6.4 gal of 7287 per 2400 barrels of water) or 60-320 ppm of DOW Antimicrobial 8536 (5.4-28.6 gal of 8536 per 2400 barrels of water). Additions should be made with a meter- ing pump immediately after preparation of the aqueous biopolymer solution to control the organisms that cause viscosity loss, or odor, or that are potential corrosive agents.

The addition of a DOW DBNPA antimicrobial as part of a total metalworking fluids management program can effectively control bacteria, fungi, and yeasts, extending the useful life of fluids, eliminating odors, and killing pathogenic bacteria. DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are registered for use in oil emulsion, synthetic, and semi-synthetic metalworking fluids. DOW DBNPA must be added to the metalworking fluid after the concentrate has been diluted with water (tankside addition). DOW DBNPA is not appropriate for addition to the metalworking fluid concentrate. Both DOW Antimicrobial 7287 and DOW Antimicrobial 8536 are effective in metalworking fluids concentrates that have been diluted in water in ratios of 1:4-1:100. Excellent performance in low pH systems The biocidal activity of DOW DBNPA antimicrobials is best in metalworking fluid systems of lower pH. For example, it would perform well in fluids used in two-piece aluminum can forming, in which the fluid pH will generally be near 6. Recommended method of addition DOW Antimicrobials 7287 or 8536 can be fed directly into the collection tank with a metering pump.
Avoid adding slug doses with a pail or open container, especially at the max- imum recommended use level; this practice can cause the local evolution of irritating vapors.
Both products can be added continuously or periodically as needed to maintain control of microbial growth. Control should be based on visual inspection, microbiological analyses, and/or experienced observations of a water treatment representative. Recommended treatment levels Bacterial, yeast, and fungal growths that may deteriorate metalworking fluids containing water can be controlled by adding DOW Antimicrobial 7287 or DOWAntimicrobial 8536 at the levels shown in Table 14 or Table 15.

The compound 2,2-dibromo-3-nitrilopro- pionamide (DBNPA) is the active ingredient in DOW Antimicrobial 7287 and DOW Antimicrobial 8536.
These products are formulated with DOW Polyglycol E-200 and/or tetraethylene glycol and water.
These formulations are the subject of U.S. Patents 3,689,660; 3,928,575; and 4,163,798, and replace those formulated with Polyglycol E-200 only.
Other patents are pending. Chemical Name: 2 ,2-dibromo-3-nitrilopropionamid

Compatibility with other water
Treatment chemicals
DOW Antimicrobial 7287 and DOW
Antimicrobial 8536 are compatible with most
water treatment chemicals, most paper chemicals, and are tolerant of high organic loads.
They are also compatible with chlorine and
exhibit a significant synergistic antimicrobial
effect when either is used as a a co-treatment with chlorine

Active Ingredient 2,2-dibromo-3-nitrilopropionamide
CAS Number
of DBNPA
1022-01-2
Percent Active 20 percent for DOW Antimicrobial
Ingredient 7287
5 percent for DOW Antimicrobial
8536
Inert Ingredients Polyethylene glycol/water
Color Clear to amber
Appearance Liquid
Odor Low, mildly antiseptic
Freezing Point About -50°C (per ASTM D-97)
Pour Point About -45°C (per ASTM D-97)
Free Flowing About -30°C (per ASTM D-97)
Freeze -Thaw
Stability Passed 7 cycles at -15° to +20°C
Boiling Point >120°C for solution, but active
ingredient decomposes
Specific Gravity 1.24-1.27 g/ml @ 23°C for (7287)
1.14-1.17 g/ml @ 23°C for (8536)
Miscibility Miscible with water in all
proportions
Vapor Pressure
(DBNPA) 2 x 10-5 mmHg @ 25°C
Flash Point None detected (COC)
Partition Coefficient P=0.1 for mineral oil/water
Storage Stability Analysis shows that 95 percent of the
original concentration of the active
ingredient in both 7287 and 8536
remains in appropriate storage

DOW Antimicrobials 7287 and 8536 are temperature sensitive.
Therefore, all external sources of heat or energy must be eliminated or controlled to ensure product stability and safety. The following are potential sources of heat or energy: sunlight, radiation, warehouse lights and heaters, agitators and pumps, and steam used to thaw a frozen line or drum. Remember that the storage volume has a direct effect on the rate of product decomposition. Customers should examine their operations carefully and consider these points. Screening tests have established suitable materials of construction for handling DOW Antimicrobial 7287 (20 percent DBNPA in polyethylene glycol). The polyethylene glycol is essentially noncorrosive, therefore, the cor- rosion potential of the two formulated products is a function of increasing DBNPA concentration. DOW Antimicrobial 7287 (20 percent DBNPA) represents the worst case, but the conclusions and recommendations presented here also should be followed for DOW Antimicrobial 8536 (5 percent DBNPA) to ensure an adequate margin of safety. Temperature/decomposition rates DOW DBNPA antimicrobials are effective and environmentally safe as biocides when properly administered. However, the active component, dibromonitrilopropionamide, is temperature sensitive and will decompose exothermically (liberate heat) at elevated tem- peratures. In addition, its decomposition rate increases with increasing temperature once the exothermic reaction begins. If DBNPA antimicrobials are stored under adiabatic conditions where this heat can- not be transferred to ambient air rapidly enough, the liquid temperature in the container will increase with decomposition, and this in turn will increase the decomposition rate. In general, there is no severe hazard with the bulk handling of the water-glycol 20 percent and 5 percent formulations of DBNPA.

Biocide DBNPA needs supporting company to stay on market
12 March 2020
Company must come forward by 10 March 2021
Europe
Biocides
Active substances
EDCs
BPR
Echa has invited companies to come forward if they would like to support the biocidal active substance 2,2-dibromo-2-cyanoacetamide (DBNPA) in the biocides review programme.

The invitation concerns the chemical’s use in:

disinfectants and algaecides not intended for direct application to humans or animals (product-type two); and
working or cutting fluid preservatives (product-type 13).
The company that was previously taking DBNPA through the review programme has withdrawn its support.

For the substance to remain on the EU market, a new supporting company needs to come forward by 10 March 2021.

DBNPA is mostly used for disinfecting food processing vessels. The substance is a potential endocrine disruptor and candidate for substitution under the biocidal products Regulation (BPR).

If nobody comes forward to support the substance, an application for its evaluation under the BPR would still be possible. However, it would need to be registered as a new active substance and products containing it remain off the market until an approval decision is made.

ACTICIDE® DB 20
20% 2,2-dibromo-3-nitrilopropionamide (DBNPA)
Pulp and paper mill process waters, cooling towers, heat exchangers and air-conditioning systems
Short term protection of industrial products such as polymer dispersions, pigment and mineral slurries and wax dispersions
Sterilant in plant hygiene improvement programmes

Technical Grade 2.2-dibromo-3-nitrilopropionamide.
Only registered for non-fifra use in the US
Quick-kill biocide.
Controls bacteria, fungi and algae in industrial processes and water systems including: paper mills, industrial cooling water systems.
Controls slime-formation in air washer systems.

Published Web Location
https://doi.org/10.1128/aem.01336-19
Production of unconventional oil and gas continues to rise, but the effects of high-density hydraulic fracturing (HF) activity near aquatic ecosystems are not fully understood.
A commonly used biocide in HF, 2,2-dibromo-3-nitrilopropionamide (DBNPA), was studied in microcosms of HF-impacted (HF+) versus HF-unimpacted (HF-) surface water streams to (i) compare the microbial community response, (ii) investigate DBNPA degradation products based on past HF exposure, and (iii) compare the microbial community response differences and similarities between the HF biocides DBNPA and glutaraldehyde. The microbial community responded to DBNPA differently in HF-impacted versus HF-unimpacted microcosms in terms of the number of 16S rRNA gene copies quantified, alpha and beta diversity, and differential abundance analyses of microbial community composition through time. The differences in microbial community changes affected degradation dynamics. HF-impacted microbial communities were more sensitive to DBNPA, causing the biocide and by-products of the degradation to persist for longer than in HF-unimpacted microcosms.
A total of 17 DBNPA by-products were detected, many of them not widely known as DBNPA by-products.
Many of the brominated by-products detected that are believed to be uncharacterized may pose environmental and health impacts.
Similar taxa were able to tolerate glutaraldehyde and DBNPA; however, DBNPA was not as effective for microbial control, as indicated by a smaller overall decrease of 16S rRNA gene copies/ml after exposure to the biocide, and a more diverse set of taxa was able to tolerate it.
These findings suggest that past HF activity in streams can affect the microbial community response to environmental perturbation such as that caused by the biocide DBNPA.IMPORTANCE Unconventional oil and gas activity can affect pH, total organic carbon, and microbial communities in surface water, altering their ability to respond to new environmental and/or anthropogenic perturbations. These findings demonstrate that 2,2-dibromo-3-nitrilopropionamide (DBNPA), a common hydraulic fracturing (HF) biocide, affects microbial communities differently as a consequence of past HF exposure, persisting longer in HF-impacted (HF+) waters. These findings also demonstrate that DBNPA has low efficacy in environmental microbial communities regardless of HF impact.
These findings are of interest, as understanding microbial responses is key for formulating remediation strategies in unconventional oil and gas (UOG)-impacted environments.
Moreover, some DBNPA degradation by-products are even more toxic and recalcitrant than DBNPA itself, and this work identifies novel brominated degradation by-products formed.

View Larger
Surface Water Microbial Community Response to the Biocide2,2-Dibromo-3-Nitrilopropionamide, Used in Unconventional Oil and Gas Extraction
Maria Fernanda Campa,a,bStephen M. Techtmann,cMallory P. Ladd,a,dJun Yan,e,fMegan Patterson,fAmanda Garcia de Matos Amaral,fKimberly E. Carter,gNikea Ulrich,hChristopher J. Grant,hRobert L. Hettich,a,dRegina Lamendella,hTerry C. Hazena,b,f,g,i,jaBredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, Tennessee, USAbBiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USAcDepartment of Biological Sciences, Michigan Technological University, Houghton, Michigan, USAdChemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USAeKey Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, People’s Republicof ChinafDepartment of Microbiology, University of Tennessee, Knoxville, Tennessee, USAgDepartment of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee, USAhDepartment of Biology, Juniata College, Huntingdon, Pennsylvania, USAiDepartment of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA
Institute for a Secure and Sustainable Environment, Knoxville, Tennessee, USA
ABSTRACT
Production of unconventional oil and gas continues to rise, but the effectsof high-density hydraulic fracturing (HF) activity near aquatic ecosystems are not fullyunderstood.
A commonly used biocide in HF, 2,2-dibromo-3-nitrilopropionamide(DBNPA), was studied in microcosms of HF-impacted (HF) versus HF-unimpacted(HF) surface water streams to (i) compare the microbial community response, (ii)investigate DBNPA degradation products based on past HF exposure, and (iii) com-pare the microbial community response differences and similarities between the HFbiocides DBNPA and glutaraldehyde.
The microbial community responded to DBNPA differently in HF-impacted versus HF-unimpacted microcosms in terms of the num-ber of 16S rRNA gene copies quantified, alpha and beta diversity, and differentialabundance analyses of microbial community composition through time.

The differ-ences in microbial community changes affected degradation dynamics.
HF-impactedmicrobialcommunities were more sensitive to DBNPA, causing the biocide and by-products of thedegradation to persist for longer than in HF-unimpacted micro-cosms.
A total of 17 DBNPA by-products were detected, many of them not widelyknown as DBNPA by-products.
Many of the brominated by-products detected thatare believed to be uncharacterized may pose environmental and health impacts.
Similar taxa were able to tolerate glutaraldehyde and DBNPA; however, DBNPA wasnot as effective for microbial control, as indicated by a smaller overall decrease of16S rRNA gene copies/ml after exposure to the biocide, and a more diverse set oftaxa was able to tolerate it.
These findings suggest that past HF activity in streamscan affect the microbial community response to environmental perturbation such asthat caused by the biocide DBNPA.

IMPORTANCE
Unconventional oil and gas activity can affect pH, total organic car-bon, and microbial communities in surface water, altering their ability to respond tonew environmental and/or anthropogenic perturbations.
These findings demonstratethat 2,2-dibromo-3-nitrilopropionamide (DBNPA), a common hydraulic fracturing (HF)biocide, affects microbial communities differently as a consequence of past HF expo-CitationCampa MF, Techtmann SM, Ladd MP,Yan J, Patterson M, Garcia de Matos Amaral A,Carter KE, Ulrich N, Grant CJ, Hettich RL,Lamendella R, Hazen TC. 2019. Surface watermicrobial community response to the biocide2,2-dibromo-3-nitrilopropionamide, used inunconventional oil and gas extraction. ApplEnviron Microbiol 85:e01336-19.https://doi.org/10.1128/AEM.01336-19.EditorRebecca E. Parales, University ofCalifornia, DavisCopyright© 2019 Campa et al. This is anopen-access article distributed under the termsof theCreative Commons Attribution 4.0International license.Address correspondence to Terry C. Hazen,tchazen@utk.edu

Applied and Environmental Microbiology16 October 2019
sure, persisting longer in HF-impacted (HF) waters. These findings also demon-strate that DBNPA has low efficacy in environmental microbial communities regard-less of HFimpact.
These findings are of interest, as understanding microbial responses iskey for formulating remediation strategies in unconventional oil and gas (UOG)-impacted environments.
Moreover, some DBNPA degradation by-products are evenmore toxic and recalcitrant than DBNPA itself, and this work identifies novel bromin-ated degradation by-products formed.

KEYWORDS: DBNPA, hydraulic fracturing, microbial communities,microbial ecology, unconventional oil and gas, water contamination

Unconventional oil and gas (UOG) extraction has revolutionized the energy industryin the United States.
The use of hydraulic fracturing (HF) has made previouslyunreachable UOG reserves available for economically feasible extraction and pushedthe United States toward energy independence (1). Multiple environmental concernshave accompanied this energy production growth.
Among the most commonly addedchemicals to HF fluids are biocides. Biocides are used in HF operations to controlmicrobially induced corrosion of casings and pipes and gas souring caused by acid-producing and sulfate-reducing bacteria (2).
However, biocides have warranted con-cern for several reasons.
Biocides have various degrees of reported efficacy due topotential resistance or inactivation of the biocides in HF conditions (2–5).
Additionally,their toxicity and potential impact on the environment remain a contentious topic (2,6).
The fate of these biocides in the environment and their impact on microbialcommunities are poorly understood.
The biocide 2,2-dibromo-3-nitrilopropionamide (DBNPA) is the second most com-monly used biocide in UOG after glutaraldehyde.
DBNPA is a fast-acting electrophilicbiocide; it is quick and effective in contact, but the protection is not long lasting (7).
This biocide inhibits essential biological functions by reacting with nucleophiles (particularlysulfur-containing nucleophiles) inside the cell (8).
DBNPA, and some of its degradationproducts, can also be harmful to humans and animals.
These associated compoundshave been demonstrated to be moderately to highly toxic by ingestion and inhalation,can be corrosive to eyes, and have been shown in terrestrial and aquatic animal studiesto cause developmental issues (9,10).
DBNPA is not toxic to all life, however, as it is biodegradable under both aerobic andanaerobic conditions, with a reported biotic half-life of less than 4 h under bothconditions at neutral pH (10).
However, the hydrolysis and aquatic photolysis half-life ofthis compound are pH-dependent, with faster degradation occurring at a more alkalinepH.
For example, the abiotic half-lives of DBNPA at pH 5, 7, and 9 are 67 days, 63 h, and73 min, respectively (10).

Conversely, low pH has been characteristic of HF-impactedstreams (11,12), which thus provide favorable conditions for the stability of DBNPA andits degradation products.
The products of DBNPA biodegradation are the same under aerobic and anaerobicmetabolism (10).
Still, the relative abundance of these degradation intermediates andtheir reported half-lives vary depending on conditions such as pH, hydrolysis, photol-ysis, nucleophile presence, and aerobic or anaerobic conditions (10,13).
There are twoknown degradation pathways of DBNPA (Fig. S1).
The first pathway involves thehydrolysis of DBNPA into dibromoacetonitrile (DBAN), then dibromoacetamide (DBAM),and finally dibromoacetic acid.
DBAN is more recalcitrant and three times more toxicthan DBNPA (13).
Dibromoacetic acid, a problematic disinfection by-product (14), has ahalf-life of 300 days and breaks down into glyoxylic acid, oxalic acid, bromide ions, andcarbon dioxide (15).
However, a higher presence of total organic carbon (TOC) and/ornucleophilic reactions under UV light favors a second degradation pathway, where DBNPA degrades to monobromonitrilopropionamide (MBNPA), a compound two timesless toxic than DBNPA (13), and then to cyanoacetamide (CAM) (13,15).
It was previously shown that HF-impacted streams have larger amounts of dissolved organic continues to rise, but the effects of high-density hydraulic fracturing (HF) activity near aquatic ecosystems are not fully understood.
A commonly used biocide in HF, 2,2-dibromo-3-nitrilopropionamide (DBNPA), was studied in microcosms of HF-impacted (HF+) versus HF-unimpacted (HF-) surface water streams to
(i) compare the microbial community response,
(ii) investigate DBNPA degradation products based on past HF exposure, and
(iii) compare the microbial community response differences and similarities between the HF biocides DBNPA and glutaraldehyde.
The microbial community responded to DBNPA differently in HF-impacted versus HF-unimpacted microcosms in terms of the number of 16S rRNA gene copies quantified, alpha and beta diversity, and differential abundance analyses of microbial community composition through time.
The differences in microbial community changes affected degradation dynamics.
HF-impacted microbial communities were more sensitive to DBNPA, causing the biocide and by-products of the degradation to persist for longer than in HF-unimpacted microcosms.
A total of 17 DBNPA by-products were detected, many of them not widely known as DBNPA by-products.
Many of the brominated by-products detected that are believed to be uncharacterized may pose environmental and health impacts.
Similar taxa were able to tolerate glutaraldehyde and DBNPA; however, DBNPA was not as effective for microbial control, as indicated by a smaller overall decrease of 16S rRNA gene copies/ml after exposure to the biocide, and a more diverse set of taxa was able to tolerate it.
These findings suggest that past HF activity in streams can affect the microbial community response to environmental perturbation such as that caused by the biocide DBNPA.

IMPORTANCE

Unconventional oil and gas activity can affect pH, total organic carbon, and microbial communities in surface water, altering their ability to respond to new environmental and/or anthropogenic perturbations.
These findings demonstrate that 2,2-dibromo-3-nitrilopropionamide (DBNPA), a common hydraulic fracturing (HF) biocide, affects microbial communities differently as a consequence of past HF exposure, persisting longer in HF-impacted (HF+) waters.
These findings also demonstrate that DBNPA has low efficacy in environmental microbial communities regardless of HF impact.
These findings are of interest, as understanding microbial responses is key for formulating remediation strategies in unconventional oil and gas (UOG)-impacted environments.
Moreover, some DBNPA degradation by-products are even more toxic and recalcitrant than DBNPA itself, and this work identifies novel brominated degradation by-products formed.

Efficacy of DBNPA against Legionella pneumophila: experimental results in a model water system.
Author(s) : GAO V., ZHOU P., LIN Y. E.

Summary

Although chlorine is the best biocide for Legionella control, corrosion is a major disadvantage associated with its use.
Nonoxidizing biocides have the advantage of reduced corrosion but may have marginal efficacy.
DBNPA (2,2-dibromo-3-nitrilopropionamide) is a nonoxidizing biocide that has demonstrated short-term efficacy against Legionella after exposure to a single dose of 8-19 ppm, but dosing at these levels is not economically feasible. Therefore, the objective of the study was to compare the efficacy of 5.0 ppm and 15.0 ppm slug doses of DBNPA vs. 5.0 ppm and 1.0 ppm with multiple dosing to achieve a residual level of 1.0 ppm of DBNPA over a 16-day period.

2 2-Dibromo-3-Nitrilopropionamide (DBNPA)
CAS No.: 10222-01-2

Molecular Formula: C3H2Br2N2O

Molecular Weight: 242

Structural Formula:

dbnpa liquid

Properties
DBNPA is white crystals. It is soluble in acetone, polyethyleneglycol, benzene, ethanol, etc.

DBNPA biocide is stable in acidic conditions and decomposed in alkaline conditions or in the presence of hydrogen sulfide.

The solid DBNPA is an efficient germicide for the recycling water system.
It can penetrate in the cytocyst of microbes quickly and kill them by reacting with some proteins in it, stopping the redox of cells.

DBNPA solid biocide has a good stripping property, little poison, and no foam in the system. The organic solutions can miscible with water.

Synthetic Methods
1. Preparing chloroacetic acid, cyanoacetic acid, dialkyl aminoacrolein, amino-acetal, and methyl cyanoacetate as starting material.
Cyanoacetamide is first made. And then you get the DBNPA biocide by Cyanoacetamide bromination.

2. The synthesis method of chloroacetic acid as starting materials: chloroacetic acid neutralizes sodium carbonate or sodium hydroxide to produce sodium chloroacetate.

Then sodium chloroacetate reacts with sodium cyanide in butanol solution to produce sodium of cyanoacetic acid.
After acidizing it with concentrated hydrochloric acid.

The esterification reaction between cyanoacetic acid with methanol or butanol, get the methyl cyanoacetate.
Then make Cyanoacetamide after aminolysis.
At last, you get DBNPA by brominating.

Specifications
Item   Index
Assay   ≥ 99%
Melting Point   122-128℃
pH (1% Aqueous Solution)   4.0-6.5
Loss on Drying   ≤ 1%
Applicaitions
As the biocides in broad-spectrum, DBNPA biocide is widely used in industrial circulating water systems, large air-condition and the large center of sewage treatment to eliminate microorganisms and alga and shuck off clay.
It is also used in the process of papermaking to prevent reducing the quality of paper by the generation of microorganisms.

This halogen biocide is suitable for metal cutting of cooling liquor, recovery system of oil, latex, and ply-woods as anti-spy biocides.
It has the following advantages: easy to handle; no unusual oxidation hazards; similar performance and safety in paper and oilfield applications; used for slime control in the wet-end of the paper mill and performs exceptionally well against slime-forming bacteria.

DBNPA has exhibited outstanding efficiency against bio-films and against a broad spectrum of bacteria, fungus, and yeasts.

Additionally, DBNPA series products are used in the short-term preservation of coatings and coating additives such as latex, starch and mineral slurries.

DBNPA is a fast-acting/quick-kill biocide that is broad-spectrum and does not contain or release formaldehyde.

Package and Storage
25kg card drums with double PE inner bag or customers’ requirements. Store in a dry cool and ventilation environment.

The storage time is two years.

Synonyms
2 2-Dibromo-2-cyanoacetamide, 2 2-Dibromo-3-nitrilopropionamide, 10222-01-2, Dibromo cyanoacetamide.

DBNPA (Section 2.6.5)
Membranes in general are prone to fouling due to several causes, one of which is biofouling caused by bacteria.
Biofouling can form a foundation to collect other debris and lead to further problems.
Symptoms of a fouled membrane include decreased permeate flow at a constant feed rate, increased pressure necessary to maintain constant permeate flow and decreased salt rejection.
In order to prevent biofouling the use of a biocide is recommended.
The biocide should be dosed from the beginning of using a new and/or clean membrane.
The following are the requirements for a biocide:
• Biocides must be compatible with the membrane.
• They must be fast acting.
• They must be cost effective.
• Biocide must have acceptable transportation, storage, stability and handling characteristics.
• Biocide should not appear in the permeate.
• Biocide must have broad spectrum control; e.g. planktonic and sessile organisms (algae control is seasonal and situational).
• They should be biodegradable.
• They should be compatible with current and upcoming regulations.

A material suited for this application is DBNPA (2,2, dibromo-3-nitrilo-proprionamide), which has the following characteristics:
• Compatible with the membrane
• Fast acting
• Cost effective
• Acceptable transportation, storage, stability and handling characteristics
• Broad spectrum control (e.g., planktonic and sessile organisms); algae control is seasonal and situational
• Biodegradable There are several DBNPA-based products available.

In RO systems operating with biologically active feed water, a biofilm can appear within 3-5 days after inoculation with viable biological organisms.
The optimal frequency for sanitization will be site specific and must be determined by the operating characteristics of the RO system.
There are two different types of application, slug dosing and continuous feed.
To both sea water and brackish industrial water production, DBNPA active ingredient, can be added to the RO feed water at a rate of up to 20 ppm, based on feed water flow, using an addition cycle of at least 30 minutes.
When used in the production of potable water, dosage limits of 3 ppm for brackish water and 12 ppm for sea water, based on the feed water flow, need to be respected.
This is to ensure that the approved SPAC (single product active concentration) of 90 ppb DBNPA is not exceeded in the permeate.
When used in potable water production, only the off-line use of DBNPA is supported.
DBNPA should not be added in the presence of sodium bisulfite residuals or other reducing agent residuals which are being added to the feed water of the RO system.
If the feed water is expected to contain measurable quantities of sodium bisulfite or other reducing agent residuals, then the addition of reducing agents must be suspended at least 15 minutes prior to the addition of DBNPA in order to avoid decomposition of the active ingredient.
Note that although DBNPA is nonoxidizing, it does give an ORP response in approximately the 400 mV range at concentrations between 0.5 and 3 mg/L.
For comparison, chlorine and bromine give a response in the 700 mV range at 1 mg/L, which increases with increasing concentration.
This increase in ORP is normal when adding DBNPA and it is recommended the ORP set-point is by-passed during DBNPA addition

March 25, 2022

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