pH adjustment may be required for a number of reasons:
To directly precipitate out chemicals otherwise present as more soluble salts
To increase the efficacy of any coagulants used
To enable discharge limits to be met
To maximise the concentration of the most efficient chlorine containing species for disinfection (e.g. hypochlorous acid vs hypochlorite)
The most commonly used chemicals for pH adjustment in effluent plants are lime, sodium hydroxide and sodium bicarbonate.
Product code
Composition
Comments
Product code
Composition
Comments
HC23
An aqueous solution of sodium hydroxide.
Concentrated alkaline pH adjuster for many applications including adjusting the pH of waste water.
HC448
Sulphuric acid
Concentrated acidic pH adjuster for many applications including adjusting the pH of waste water.
HC903
Lime suspension
An alkali for use in pH control of potable water, effluent treatment and flue gas treatment.
HC411
Phosphoric acid
Concentrated acidic pH adjuster for many applications including adjusting the pH of waste water.
HC228
Sodium Bicarbonate
Powder product for neutralising acid solutions
HC1017
Sodium carbonate solution
Liquid product used to increase the alkalinity of waste water.
Coagulants
Many of the solid particles in water are as suspended solids (a colloid). They are very small electrically charged particles which repel each other and will not settle out of suspension by gravity alone in a reasonable timeframe; hence the need for chemical treatment. This typically results in the removal of 80-90% of suspended solids by chemical precipitation.
Coagulants act by neutralising the charge which enables the particles to come together forming slightly larger particles or microflocs.
Traditional coagulants were inorganic compounds, and can have advantages over the inorganic coagulants in that the produced sludge volume is often less, sludge disposal costs can be lower and they are less pH dependent.
Product code
Composition
Comments
Product code
Composition
Comments
HC784
Tannin based coagulant
An aqueous solution of a complex organic polymer coagulant. Particularly appropriate for use in splitting oil- water emulsions. This product is also suitable for use in many applications such as the food industry, oil fields, petrochemical plants and metal working plants.
HC627
An aqueous solution of polyaluminium chloride.
A cost-effective primary coagulant product. Good insoluble organics removal giving effective BOD/COD reduction. Excellent phosphorous removal. Good colour removal.
HC699
Aluminium hydroxide chloride
Versatile product. Intrinsic buffering reduces pH swings. Good organics /colour removal. Also excellent phosphorous removal
HC611
Polyaluminium chloride.
A cost-effective primary coagulant product. Good insoluble organics removal giving effective BOD/COD reduction. Excellent phosphorous removal. Good colour removal.
HC626
Trivalent aluminium enhanced by a powerful, highly charged cationic polymer.
Effective BOD/COD removal with good organics/colour removal. An easy to feed liquid which produces lower sludge volumes. Excellent phosphorous removal,
HC390
Ferric chloride
Effective in clarification. Reduces phosphate levels. Reduces levels of heavy metals (e.g. lead, coper, cadmium and zinc)
HC417
An aqueous solution of ferric ions
Effective BOD/COD removal with good organics/colour removal. Excellent phosphorous removal
Flocculants
The addition of flocculants brings the microflocs into contact resulting in their bonding and formation of flocs which are large enough for them to be separated out from the waste water. The flocculants are organic polymers (generally polyacrylamide) with varying charge densities and molecular weights. They act by forming a “bridge” between the microflocs. Mixing which should be gentle is critical to the performance of the flocculant and is generally done by mechanical or air agitation; overmixing can lead to the breakdown of the flocs.
HydroChemie can supply flocculants in different forms including powders and emulsions in a variety of different molecular weights and charge densities.
Product code
Composition
Comments
Product code
Composition
Comments
HC600
Polyacrylamide in oil based emulsion
A low charge density anionic water soluble polymer in oil based emulsion for use as a flocculant across a range of industries
HC601
A high molecular weight, medium charge density, anionic latex emulsion polymer
Ensures high clarity of the treated water from applications such as: flotation, sedimentation, filtration, thickening, centrifugation and belt pressing.
HC641
High charge, high molecular weight cationic polymer. Liquid formulation.
A superior quality flocculant for the removal of suspended solids. Suitable for raw water clarification, primary and secondary effluent clarification and oily waste water clarification.
HC796
A powder product with a medium anionic charge density and very high molecular weight
An anionic flocculant primarily for use in clarification following coagulation to aid settlement or flotation depending on the treatment process.
HC610
A powder product with very high charge density and molecular weight cationic polymer
A superior quality flocculant for the removal of suspended solids. Suitable for raw water clarification, primary and secondary effluent clarification and oil waste water clarification.
HC1023
A medium molecular weight anionic copolymer of acrylamide in a water based emulsion
An anionic flocculant primarily for use in clarification following coagulation to aid settlement or flotation depending on the treatment process.
HC423
A high molecular weight anionic copolymer of acrylamide in emulsion
A medium charge density anionic flocculant primarily for use in clarification following coagulation to aid settlement or flotation depending on the treatment process.
HC1081
Cationic Polyacrylamide based
Unique, high molecular weight cross linked flocculant of high charge This product is especially effective in those applications where extreme high molecular weight products are needed such as screw presses, centrifuges, and belt filter presses.
HC964
A cationic polyacrylamide of very high charge density and high molecular weight in emulsion.
A cationic flocculant primarily for use in clarification following coagulation to aid settlement or flotation depending on the treatment process.
HC1501
An anionic polyacrylamide in an aqueous dispersion
The product is a polymer in an aqueous dispersion - free of solvents, oils and surfactants. It provides “a more ecological” way of working" than traditional emulsion products and is also easier to use with increased product stability and without the requirement for specialised make-down equipment.
HC1508
An aqueous solution of cationic water soluble polymer in an emulsion.
A cationic flocculant primarily for use in clarification following coagulation to aid settlement or flotation depending on the treatment process.
HC1506
A cationic polyacrylamide of very high charge density and high molecular weight in emulsion.
A cationic flocculant primarily for use in clarification following coagulation to aid settlement or flotation depending on the treatment process.
HC1521
Cationic copolymer of acrylamide and cationic monomer in powder form.
A polyelectrolyte for the conditioning of a variety of sludge’s produced in waste-water treatment, prior to mechanical or static dewatering. It is a powder and needs to be prepared, as a solution, before use. Highly effective
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across a wide range of applications including mechanical dewatering, thickening, flotation and clarification. Operates over a wide pH range - typically pH 4-9.
Antifoams
Antifoam agents are often used in both sewage treatment plants as well as in other industrial waste water treatment applications. HydroChemie have a variety of antifoam formulations, both organic and inorganic. A small selection is shown below.
Product code
Composition
Comments
Product code
Composition
Comments
HC1546
Concentrated Silicone emulsion
Applied directly to the foam it causes rapid "Foam Kill" whereby the foam collapses. Foam will quickly return unless dosing is continuous at low levels
HC1554
Organic based antifoam
Inhibits the build-up of foams in systems containing proteins, starches, yeasts, synthetic resins and fibrous/particulate materials. Suitable for use in the anaerobic digestion of effluent sludge, fermentation of yeasts, citric acid and other aerobic systems.Suitable for use in recirculating scrubbing systems containing high levels of particulates and electrolytes.
HC617
Silicone based antifoam.
A concentrated emulsion - acts both as a foam killer and foam preventer. Useful in many applications including waste water process applications.
Odour Control
Odours are not infrequently generated in effluent plants and may be particularly associated with the sludge which contains higher concentrations of odorous chemicals. HydroChemie have a number of products which are able to neutralise many odours such as those associated with hydrogen sulphide, ethylamines, butylamines, mercaptans, fatty acids and ammonia.
Product code
Composition
Comments
Product code
Composition
Comments
HC623
Natural plant oils in aqueous solution.
Reacts with odour causing molecules in the gas/vapour phase. Neutralises ammonia, rendering, faecal, indolic, decomposing, sour and fishy odours. Dissipates rapidly, leaving no malodours or fragrance.
HC909
Natural plant oils in aqueous solution.
Dilute solution of HC623
HC631
An aqueous blend of nutrients and anti-sulphides.
Blend of nutrients designed to inhibit the conversion of sulphate to sulphide.
Disinfectants
HydroChemie have a number of oxidising biocide products which can be used in disinfection applications.
Product code
Composition
Comments
Product code
Composition
Comments
HC102
Sodium Hpochlorite
Chlorine is able to achieve disinfection goals through bacteria and virus inactivation. Chlorine can also oxidize and degrade soluble contaminants, such as agricultural or pharmaceutical compounds present in wastewater
HC103
Hydrogen peroxide
Hydrogen peroxide is used to reduce the BOD and COD of industrial wastewaters and for the pre-treatment of waters that contain some contaminants that are toxic, inhibitory, or recalcitrant to biological treatment (e.g., pesticides, plasticizers, resins, coolants, and dyestuffs)
HC19
9% Hydrochloric acid
Dosed 1:1 with HC123 through a chlorine dioxide generator to produce chlorine dioxide. Chlorine dioxide is effective as both a disinfectant and an oxidant in wastewater treatment where It destroys phenolics, simple cyanides and sulphides by oxidation.
HC123
An 8% solution of sodium chlorite
Dosed 1:1 with HC19 through a chlorine dioxide generator to produce chlorine dioxide. Chlorine dioxide is effective as both a disinfectant and an oxidant in wastewater treatment where It destroys phenolics, simple cyanides and sulphides by oxidation.
