Cooling — Process Challenge

Microbiological Control in Cooling Water Systems

Warm, aerated, nutrient-rich cooling water grows bacteria, algae and biofilm (including SRB) that foul fill, cause under-deposit corrosion and harbor Legionella. Design pairs oxidizing biocides for bulk kill with non-oxidizers and a quat for biofilm and resistant organisms
Updated Jun 2026
Solution Approach

RawSource supplies the base chemicals that go into these programs. We can help with product selection, grade matching, and sourcing from multiple origins for supply security.

Typical Treatment Workflow
1
Water & System Assessment
Characterize the water and the system — hardness, alkalinity, pH, TDS/conductivity, microbial load, and the metallurgy and temperatures of the equipment being protected.
2
Program & Chemistry Selection
Match coagulants, flocculants, scale and corrosion inhibitors, biocides, or pH adjusters to the water profile and discharge limits, factoring compatibility with any existing program.
3
Jar Testing & Dosing
Confirm coagulant and flocculant dose and feed point by jar test, set inhibitor and biocide treat rates, and size packaging (drums, totes, bulk) to consumption.
4
Monitoring & Control
Track residuals, turbidity, ORP, corrosion coupons, and effluent compliance, adjusting chemistry and dose as feedwater and load change.
Recommended Chemistries (8)
Sodium Hypochlorite
CAS 7681-52-9
Acids & Salts
Primary oxidizing biocide
1791 (SODIUM HYPOCHLORITE) · Class
Primary oxidizing biocide; hypochlorite/HOCl oxidizes cell membranes for broad, low-cost bulk-water kill. (Spine tags this pH Adjustment; the chemistry is oxidizing-biocide.)
Melting Point: MP: 18 °C /Pentahydrate/   Boiling Point: Boiling point: 111 °C in solution   Density: 1.093 for 5% solution
Quick view
Full Details
Calcium Hypochlorite
CAS 7778-54-3
Specialty Additives
Biocidal Action
2208 (BLEACHING POWDER) · Class
Solid chlorine donor delivering HOCl where liquid bleach handling/decay is impractical; same oxidative disinfection mechanism
Melting Point: 100 °C   Boiling Point: Decomposes at 100 °C   Density: 2.350 g/cu cm
Quick view
Full Details
Sodium Dichloroisocyanurate (SDIC)
CAS 2893-78-9
Specialty Additives
Biocidal Action
2465 (SODIUM DICHLORO-S-TRIAZINETRIONE) · Class
Stabilized (chloroisocyanurate) chlorine releases HOCl slowly, holding a more persistent oxidant residual than free chlorine
Melting Point: 225 °C   Density: 0.96 at 20 °C   Solubility: Soluble
Quick view
Full Details
Chlorine Dioxide
CAS 10049-04-4
Specialty Additives
Biocidal Action
9191 (CHLORINE DIOXIDE) · Class
ClO2 stays biocidal across a wide pH and penetrates biofilm better than chlorine, and does not form THMs; strong against established slime
Melting Point: -59 °C   Boiling Point: 11 °C at 760 mmHg   Density: 1.6 (Liquid at 0 °C)
Quick view
Full Details
DBNPA (2,2-Dibromo-3-Nitrilopropionamide)
CAS 10222-01-2
Specialty Additives
Fast-acting non-oxidizing biocide
2923 (2,2-DIBROMO-3-NITRILOPROPIONAMIDE) · Class
Fast-kill non-oxidizing biocide that hydrolyzes quickly to low-residual products; ideal for slug dosing where an oxidizer demand is too high
Melting Point: 123 to 126 °C   Boiling Point: Decomposes at 190 °C   Solubility: In water, 1.5 g/100 mL (15,000 mg/L)
Quick view
Full Details
Glutaraldehyde
CAS 111-30-8
Specialty Additives
Broad-spectrum biocide
2810 (GLUTARALDEHYDE SOLUTION) · Class
Dialdehyde cross-links cell-wall proteins; the standard non-oxidizer for biofilm and sulfate-reducing-bacteria (SRB) control, effective in dirty/high-demand water
Melting Point: < -7 °C   Boiling Point: 187–189 °C at 760 mmHg (decomposes)   Density: 1.062 to 1.124 at 20 °C
Quick view
Full Details
Benzalkonium Chloride (BKC, ADBAC)
CAS 8001-54-5
Surfactants
Quaternary ammonium biocide
2928 · Class
Cationic quat disrupts membranes and acts as a biodispersant that lifts biofilm off surfaces, complementing the oxidizers
Melting Point: 241.02 °C   Density: 0.9429 g/cu cm at 25 °C   Solubility: Very soluble in alcohol, acetone; slightly solu…
Quick view
Full Details
Isothiazolinone(CMIT/MIT)
CAS 26172-55-4
Specialty Additives
Preservation
CMIT/MIT isothiazolinone is a standard rotational non-oxidizing cooling-tower biocide for algae/bacteria, alternated with DBNPA/glutaraldehyde to limit resistance.
Melting Point: 54-55 °C   Density: For a mixture of 5-chloro-2-methyl-3(2H)-isothi…   Solubility: Solubility in g/100 mL solvent: water, infinite
Quick view
Full Details

Need help selecting the right chemistry?

Our team can help with grade selection, dosage guidance, and multi-origin sourcing.

Request Quote All Water Treatment Problems
Request Quote