Water Treatment Chemicals: A Guide for Industrial Facilities

Water is the most widely used process fluid in industrial manufacturing — and one of the most problematic. Untreated or poorly treated water causes scale buildup, corrosion, biological fouling, and equipment failures that cost facilities far more than a proper treatment program ever would.

Understanding the chemistry behind industrial water treatment helps you make better decisions about your treatment program, your chemical selection, and your maintenance intervals.

The consequences of inadequate water treatment are well-documented and expensive:

• Scale — mineral deposits (primarily calcium carbonate and calcium sulfate) insulate heat transfer surfaces. As little as 1/8 inch of scale on a boiler tube increases fuel consumption by 25% and can cause tube failure from overheating.
• Corrosion — dissolved oxygen, low pH, and biological activity attack metal surfaces in boilers, cooling towers, and piping. Corrosion-related failures account for a significant share of unplanned industrial downtime.
• Biological fouling — bacteria, algae, and biofilm in cooling water systems reduce heat transfer efficiency, accelerate corrosion (microbiologically influenced corrosion, or MIC), and can harbor Legionella — a serious public health and liability concern.

A well-designed water treatment program addresses all three simultaneously.

Boiler water treatment has two goals: prevent scale on heat transfer surfaces and prevent corrosion in the boiler and steam distribution system.

Scale prevention requires controlling the hardness minerals (calcium and magnesium) that concentrate as water evaporates. Treatment approaches include:

• Softening — ion exchange removes hardness ions before water enters the boiler
• Scale inhibitors — phosphate-based or polymer-based chemicals keep hardness minerals in suspension and prevent them from depositing on surfaces
• Blowdown management — periodically draining a portion of boiler water to control dissolved solids concentration

Corrosion prevention requires:

• Oxygen scavengers — dissolved oxygen is the primary cause of boiler corrosion. Sodium sulfite and hydrazine alternatives (DEHA, carbohydrazide) chemically remove dissolved oxygen from feedwater.
• pH control — boiler water should be maintained at pH 10–11 (slightly alkaline) to minimize corrosion. Caustic soda (sodium hydroxide) or alkalinity builders are used to maintain pH.
• Filming amines — protect steam lines and condensate return piping by forming a protective film on metal surfaces.

Cooling towers are open recirculating systems — water evaporates continuously, concentrating dissolved minerals and providing an ideal environment for biological growth. Treatment must address scale, corrosion, and biology simultaneously.

Scale and deposit control:

• Scale inhibitors — phosphonate and polymer-based inhibitors prevent calcium carbonate, calcium sulfate, and silica scale from forming on heat exchanger surfaces and fill media
• Dispersants — keep suspended particles from settling and forming deposits

Corrosion control:

• Corrosion inhibitors — azole-based inhibitors protect copper alloys; molybdate or orthophosphate inhibitors protect steel. Most modern cooling water programs use blended inhibitor packages.
• pH control — cooling water is typically maintained at pH 7.0–8.5 to balance scale and corrosion tendencies

Biological control:

• Oxidizing biocides — chlorine (as sodium hypochlorite or chlorine gas), bromine (as BCDMH), and chlorine dioxide kill planktonic bacteria and control biofilm. Oxidizing biocides are the backbone of most cooling water microbiological programs.
• Non-oxidizing biocides — isothiazolone, glutaraldehyde, and DBNPA penetrate biofilm and address organisms resistant to oxidizing treatment. Used in rotation with oxidizing biocides to prevent resistance.
• Legionella management — facilities with cooling towers should have a written water management plan per ASHRAE 188. Maintaining proper biocide residuals, controlling pH, and regular system inspections are the core controls.

Process water treatment varies widely by industry and application, but common chemical needs include:

• pH adjustment — acids (sulfuric, hydrochloric) and bases (caustic soda, soda ash) to bring process or discharge water to target pH
• Coagulants and flocculants — aluminum sulfate (alum), ferric chloride, and polymer flocculants aggregate suspended solids for removal by settling or filtration
• Dechlorination — sodium bisulfite or sodium thiosulfate removes residual chlorine before discharge or reuse
• Reverse osmosis antiscalants — protect RO membranes from mineral scaling in high-recovery systems

In any recirculating water system, the ratio of dissolved solids in the circulating water to dissolved solids in the makeup water is called cycles of concentration (CoC). As water evaporates, dissolved minerals concentrate — at 4 cycles, the circulating water has 4x the mineral content of the makeup.

Operating at higher cycles of concentration conserves water and reduces chemical consumption, but increases the risk of scale and corrosion if the treatment program is not properly calibrated. Most cooling tower programs target 3–6 cycles depending on makeup water quality and system metallurgy.

Your water treatment program should be designed around your actual makeup water analysis — not generic recommendations. A water analysis from your local source is the starting point for any serious treatment program.

A water treatment program is only as good as its monitoring. Key parameters to track:

• pH — daily or continuous monitoring
• Conductivity — proxy for total dissolved solids concentration; used to control blowdown
• Biocide residual — verify oxidizing biocide is present at effective levels
• Inhibitor residual — confirm corrosion and scale inhibitors are at target concentration
• Biological counts — periodic dip slides or lab cultures to verify microbiological control
• Corrosion coupons — metal coupons installed in the system provide a direct measure of corrosion rate over time

Automated controllers for pH, conductivity, and biocide feed reduce labor and improve consistency compared to manual dosing.

The right supplier provides more than product. Look for:

• Technical support — ability to review your water analysis and recommend a treatment program
• Full product range — scale inhibitors, corrosion inhibitors, biocides, and pH adjustment chemicals from a single source simplifies procurement
• Reliable supply — treatment programs require consistent chemical availability; a supply disruption can compromise your entire system
• SDS and compliance documentation — current Safety Data Sheets and regulatory documentation for all products

Chemical and Filtration Products of Texas supplies a full range of water treatment chemicals for boiler, cooling tower, and process water applications across Texas. Contact us to discuss your water treatment requirements or request a quote.