Water & Effluent Treatment
Water and effluent treatment chemicals are chosen by treatment stage: coagulation and flocculation, pH correction, dechlorination, adsorption, softening and odour control. The right product and dose depend on the raw water or effluent, so jar testing on a representative sample is always the first step.
What the application needs. Coagulants neutralise the charge on suspended and colloidal particles so they can agglomerate. Aluminium sulfate (alum) is the traditional choice. Polyaluminium chloride (PAC) works over a wider pH range, consumes less alkalinity and usually produces less sludge. Ferrous sulfate is used for phosphorus removal, for sludge conditioning and as a reducing agent, for example to reduce hexavalent chromium in plating effluent. Flocculants such as cationic polyacrylamide (CPAM) then bridge the small flocs into larger, faster-settling ones and are widely used for sludge thickening and dewatering. Caustic soda, hydrated lime and soda ash raise pH, add alkalinity and precipitate metals as hydroxides. Sodium bisulfite, sodium metabisulfite and sodium thiosulfate remove residual chlorine before discharge or ahead of reverse-osmosis membranes. Activated carbon adsorbs organics, colour, taste and odour. Sodium hexametaphosphate acts as a threshold scale inhibitor, softener salt regenerates ion-exchange softeners, and dedicated phosphorus-removal and odour-control products address specific discharge limits.
Key specification parameters. Coagulants are specified by active content: Al2O3 percentage and basicity for PAC, which is sold as a liquid or as a spray-dried powder, and Al2O3 content for alum. Also check iron, insolubles and heavy-metal impurities. Ferrous sulfate is specified by FeSO4 content and hydration state (heptahydrate or monohydrate). For polyacrylamides, agree ionic character, charge density, molecular weight or standard viscosity, and dissolution time. Activated carbon is specified by iodine number, particle size (powdered or granular), ash, moisture and base material. For public drinking-water treatment in the UK, products generally need approval under Regulation 31 of the water quality regulations and conformity with the relevant BS EN product standard, so ask whether the offered grade holds that approval before you specify it for potable use.
Recommended product types. Most municipal and industrial clarifiers start with PAC or alum, tuned by jar test, followed by a polymer where settling or dewatering is poor. Caustic soda pearls or liquid caustic are the cleanest way to raise pH without adding hardness, while hydrated lime is cheaper for heavy acid neutralisation and metals precipitation but adds solids. Sodium bisulfite is the usual dechlorinating agent upstream of membranes, and powdered activated carbon suits intermittent taste and odour events.
Handling notes. PAC and alum solutions are acidic and corrode mild steel, so store them in HDPE, GRP or rubber-lined tanks. Ferrous sulfate oxidises and cakes when exposed to air and moisture. Make up polyacrylamide solutions at low concentration with gentle mixing and allow ageing time for full hydration; spills are extremely slippery. Bisulfite and metabisulfite release sulfur dioxide on contact with acids, so keep them separated from acid storage. Caustic soda and lime are corrosive, and dust from lime and PAC powder needs respiratory protection. Ask for the specification and safety data sheet for each product, and confirm the dose on your own water before placing a production order.
Products for Water & Effluent Treatment
Phosphoric Acid
Phosphoric acid (CAS 7664-38-2) is the parent compound of every phosphate salt in the catalogue. A triprotic acid supplied at 75 to 85 percent, it is used directly for metal phosphating, descaling and as a rust converter.
Trisodium Phosphate
Trisodium phosphate, TSP (CAS 7601-54-9), is the fully neutralised sodium phosphate and the most alkaline of the series, dissolving to around pH 12. It is a powerful degreaser and the traditional pre-paint surface cleaner.
Sodium Hexametaphosphate (SHMP)
Sodium hexametaphosphate, SHMP (CAS 10124-56-8), is a glassy polyphosphate that sequesters calcium and magnesium extremely strongly. It is the standard threshold scale inhibitor in cooling water and the deflocculant in ceramic slips.
Dipotassium Hydrogen Phosphate (DKP)
Dipotassium hydrogen phosphate, DKP (CAS 7758-11-4), is the alkaline potassium phosphate. In industry it supplies both potassium and phosphorus in a single soluble salt, which suits fertigation and fermentation media.
Potassium Dihydrogen Phosphate (MKP)
Potassium dihydrogen phosphate, MKP (CAS 7778-77-0), is the 0-52-34 soluble fertiliser, supplying phosphorus and potassium with no nitrogen at all. That makes it the standard choice for flowering and fruiting stages.
Disodium Hydrogen Phosphate (DSP)
Disodium hydrogen phosphate, DSP (CAS 7558-79-4), is the middle sodium phosphate, alkaline at around pH 9. In industry it is a buffer, a detergent builder and a boiler water treatment that prevents hard scale.
Sodium Dihydrogen Phosphate (MSP)
Sodium dihydrogen phosphate, MSP (CAS 7558-80-7), is the acidic sodium phosphate, dissolving to around pH 4.5. It is the acid half of the phosphate buffer pair and a mild acidulant for industrial processes.
Tetrasodium Pyrophosphate (TSPP)
Tetrasodium pyrophosphate, TSPP (CAS 7722-88-5), is the simplest condensed phosphate, formed by joining two phosphate units. Alkaline and strongly dispersing, it is used as a detergent builder and a drilling mud thinner.
Monoammonium Phosphate (MAP)
Monoammonium phosphate, MAP (CAS 7722-76-1), is the 11-52-0 fertiliser grade with the highest phosphorus content of the common straight phosphates. It is also the active powder in ABC dry chemical fire extinguishers.
Diammonium Phosphate (DAP)
Diammonium phosphate, DAP (CAS 7783-28-0), is the 18-46-0 fertiliser and the most traded phosphate fertiliser in the world. Unlike MAP it dissolves to an alkaline solution, which matters on high-pH soils.
Dicalcium Phosphate (DCP)
Dicalcium phosphate, DCP (CAS 7757-93-9), is a white insoluble powder supplying calcium and phosphorus in roughly the ratio bone uses them. Its largest market is animal feed, where it is the standard mineral supplement.
Tricalcium Phosphate (TCP)
Tricalcium phosphate, TCP (CAS 7758-87-4), is a very fine insoluble powder with a high specific surface area. That surface area is what makes it one of the most effective anticaking agents available for hygroscopic powders.
Manganese Sulfate
Manganese sulfate (CAS 7785-87-7) supplies manganese, an essential micronutrient required in the photosynthetic complex that splits water. Deficiency shows as interveinal chlorosis on young leaves, unlike magnesium deficiency.
Magnesium Sulfate
Magnesium sulfate, Epsom salt as the heptahydrate (CAS 10034-99-8), is the cheapest soluble magnesium source. Grade is selected by hydration state, since the heptahydrate and the monohydrate differ substantially in magnesium content.
Zinc Sulfate
Zinc sulfate (CAS 7733-02-0) supplies zinc, the micronutrient most often deficient in cereals worldwide. Zinc availability collapses on alkaline and high-phosphate soils, which is where correction is usually needed.
Ammonium Sulfate
Ammonium sulfate (CAS 7783-20-2) is a 21-0-0 fertiliser that supplies sulphur alongside nitrogen. Its acidifying reaction in soil is a genuine agronomic tool on alkaline ground and a drawback on already acid soils.
Copper Sulfate
Copper sulfate pentahydrate (CAS 7758-99-8) is the bright blue crystalline copper salt. It is an algaecide, a fungicide and the copper source in Bordeaux mixture, and it is highly toxic to fish and aquatic invertebrates.
Sodium Sulfate Anhydrous
Sodium sulfate anhydrous (CAS 7757-82-6) is a chemically inert, non-hygroscopic white powder. It is used in enormous volume as a detergent filler and, in textile dyeing, to drive dye onto the fibre rather than leave it in the bath.
Sodium Bisulfate
Sodium bisulfate (CAS 7681-38-1) is a dry acid: a solid salt that dissolves to give a strongly acidic solution near pH 1. It replaces liquid mineral acid wherever handling concentrated acid is the thing to avoid.
Alum
Alum, aluminium sulfate (CAS 10043-01-3), is the classic coagulant of municipal water treatment. Dosed into raw water it hydrolyses to aluminium hydroxide floc, which sweeps suspended solids and colour out of suspension.
Ferrous Sulfate
Ferrous sulfate (CAS 7720-78-7) is iron in the reduced divalent state, which is what makes it useful. It reduces hexavalent chromium in cement to the harmless trivalent form, preventing chromate contact dermatitis in workers.
Sodium Metabisulfite
Sodium metabisulfite (CAS 7681-57-4) is the solid, more stable and more concentrated form of the bisulfite chemistry. It is preferred where a dry material is easier to ship and store than a bulk sulfite solution.
Sodium Thiosulfate
Sodium thiosulfate (CAS 7772-98-7) is the classic photographic fixer, hypo, and a fast dechlorinating agent. It also reacts with cyanide to form far less toxic thiocyanate, which is the basis of its medical use as an antidote.
Sodium Sulfite Anhydrous
Sodium sulfite anhydrous (CAS 7757-83-7) is the neutral-to-alkaline member of the sulfite family. It scavenges oxygen without driving pH down, which is why it is the boiler feedwater choice where acidity would corrode.
Sodium Bisulfite
Sodium bisulfite (CAS 7631-90-5) is a reducing agent and oxygen scavenger, supplied as a solution or solid. Its largest single use is dechlorinating water ahead of reverse osmosis membranes, which chlorine destroys.
Oxalic Acid
Oxalic acid (CAS 144-62-7) is the strongest common organic acid and a powerful reducing agent. It removes iron stains by chelating iron into a soluble complex, which is why it bleaches wood and cleans rust marks.
Sodium Carbonate (Soda Ash)
Sodium carbonate (CAS 497-19-8), soda ash, is consumed in greater tonnage by glass manufacture than by every other use combined. It lowers the melting point of silica from about 1,700 to nearer 1,000 degrees Celsius.
Ammonium Bicarbonate
Ammonium bicarbonate (CAS 1066-33-7) decomposes completely to gas at modest temperature, leaving no solid residue at all. That makes it a chemical blowing agent for foamed rubber, plastics and ceramics.
Sodium Dodecyl Sulfate (SLS)
Sodium dodecyl sulfate (CAS 151-21-3) is the standard laboratory anionic detergent as well as an industrial surfactant. In SDS-PAGE it denatures proteins and coats them with uniform negative charge so they separate purely by size.
Sodium Bicarbonate
Sodium bicarbonate (CAS 144-55-8) is used industrially as a dry sorbent and a mild abrasive. Injected into hot flue gas it decomposes into a highly porous soda that captures sulphur dioxide and hydrogen chloride.
Sodium Metasilicate
Sodium metasilicate is a strongly alkaline silicate that protects aluminium while cleaning it. The silicate deposits a thin film on the metal surface, which is why alkaline aluminium cleaners contain it and plain caustic cannot be used.
Sulfamic Acid
Sulfamic acid (CAS 5329-14-6) is a solid, non-volatile strong acid used for descaling. Unlike hydrochloric acid it contains no chloride, so it can be used on stainless steel without risking chloride stress corrosion cracking.
Sodium Citrate
Sodium citrate (CAS 68-04-2) is the neutral salt of citric acid, used industrially as a sequestrant and buffer where free acid would attack the substrate. It chelates without dropping pH.
Citric Acid
Citric acid (CAS 77-92-9) is used industrially as a chelating agent rather than as an acidulant. It binds calcium, iron and copper into soluble complexes, which is the basis of its use in descaling and metal passivation.
Sodium Acetate
Sodium acetate (CAS 127-09-3) is the salt behind reusable heat pads. A supersaturated solution stays liquid far below its freezing point, then crystallises on a trigger and releases the stored heat.
Sodium Benzoate
Sodium benzoate (CAS 532-32-1) is a vapour-phase and contact corrosion inhibitor for ferrous metals. In engine coolants and hydraulic fluids it passivates steel surfaces at low dose without the toxicity of chromate inhibitors.
Benzoic Acid
Benzoic acid (CAS 65-85-0) is used industrially as a chemical intermediate and corrosion inhibitor rather than as a preservative. It is the feedstock for phenol, caprolactam and benzoate plasticisers.
Potassium Benzoate
Potassium benzoate (CAS 582-25-2) delivers the same benzoate chemistry as the sodium salt without contributing sodium. It is specified where sodium would raise conductivity or interfere with the system being protected.
Potassium Carbonate
Potassium carbonate (CAS 584-08-7), potash, is the reagent behind the hot potassium carbonate process for removing carbon dioxide from industrial gas streams at high pressure and temperature.
Sodium Propionate
Sodium propionate (CAS 137-40-6) is the more soluble propionate salt, which suits liquid dosing and spray application. It is used where a calcium contribution would be unwanted or would disturb a formulation.
Ammonium Propionate
Ammonium propionate (CAS 17496-08-1) is supplied as a solution rather than a powder because it is deliquescent. It preserves high-moisture grain while contributing non-protein nitrogen that rumen microbes can use.
Calcium Acetate
Calcium acetate (CAS 62-54-4) is used industrially as a chloride-free concrete set accelerator, a phosphate binder, and the agent that gels alcohol into the solid fuel burned in chafing dish heaters.
Calcium Propionate
Calcium propionate (CAS 4075-81-4) is used industrially as a mould inhibitor in animal feed and stored grain. It also acts as a mild set retarder and corrosion inhibitor in concrete formulations.
Potassium Acetate
Potassium acetate (CAS 127-08-2) is the standard runway and aircraft de-icer. Unlike chloride de-icers it does not corrode aluminium airframes or attack the carbon brake assemblies that chlorides destroy.
Zinc Acetate
Zinc acetate (CAS 557-34-6) is a soluble zinc salt used as a crosslinker, mordant and wood preservative. Its solubility in both water and organic solvents sets it apart from the oxide and carbonate.
Sodium Dehydroacetate
Sodium dehydroacetate (CAS 4418-26-2, INCI Sodium Dehydroacetate) is a broad-spectrum cosmetic preservative that stays active at near-neutral pH, where benzoate and sorbate have largely stopped working.
Polyaluminium Chloride (PAC)
Polyaluminium chloride, PAC (CAS 1327-41-9), is a pre-hydrolysed aluminium coagulant. Because the hydrolysis is done during manufacture rather than in the water, it works across a wider pH range and consumes far less alkalinity than alum.
Cationic Polyacrylamide (CPAM)
Cationic polyacrylamide, CPAM, is a high molecular weight flocculant that works by bridging rather than charge neutralisation. Its long chains adsorb onto several particles at once and pull them into large, shear-resistant flocs.
Phosphorus Remover
Phosphorus remover is a metal salt coagulant dosed to precipitate dissolved phosphate out of wastewater. Consent limits are typically set at 1 mg/l or below, which biological treatment alone rarely achieves.
Plant-Based Odour Remover
Plant-based odour remover uses essential oil constituents that bind or chemically neutralise odour molecules rather than covering them with fragrance. It acts immediately, where a microbial product takes days to establish.
Microbial Odour Remover
Microbial odour remover is a bioaugmentation product containing selected bacterial cultures and nutrients. It does not mask odour; the organisms degrade the compounds producing it, so the source is removed rather than covered.
Soft Water Salt
Soft water salt is high-purity sodium chloride (CAS 7647-14-5) supplied as tablets, granules or blocks. It does not soften water itself; it regenerates the ion exchange resin that does, by driving calcium and magnesium off it.
Activated Carbon
Activated carbon is carbon processed to develop an enormous internal pore network, commonly 500 to 1,500 square metres of surface area per gram. Adsorption happens on that internal surface, so grade is specified by pore structure.
Caustic Soda Pearls
Caustic soda pearls (CAS 1310-73-2) are sodium hydroxide in small spherical beads at 99 percent minimum. The round form flows freely, generates far less dust than flakes and cakes more slowly on storage.
Caustic Soda Flakes
Caustic soda flakes (CAS 1310-73-2) are sodium hydroxide in thin flake form at 99 percent minimum. The large surface area dissolves fast, but it also makes the flakes dusty and quick to absorb atmospheric moisture.
Calcium Hydroxide
Calcium hydroxide (CAS 1305-62-0), hydrated or slaked lime, is the cheapest bulk alkali available. It is only slightly soluble, which is precisely what makes lime slurry a self-buffering pH control reagent.
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