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Effluent Treatment

We all know that water supply costs are going to carry on rising – so are water disposal costs. The more contaminated your effluent, the more your effluent handling company will charge you. Increasingly stringent discharge consent conditions are also being applied.

With the right treatment, a very significant proportion of waste process water may be perfectly suitable for reuse in other processes elsewhere on site, please take some time to study our effluent Waste water treatment chemical solutions.

Hydrolink Technologies Limited has an extensive range of products including:


Flocculants (Polyelectrolytes)

To promote the formation of flocs in water that contains suspended solids polymer flocculants (polyelectrolytes) are applied to promote bonds formation between particles. These polymers have a very specific effect, dependent upon their charges, their molar weight and their molecular degree of ramification. The polymers are water-soluble and their molar weight varies between 105 and 106 g/ mol.
There can be several charges on one flocculent. There are cationic polymers, based on nitrogen, anionic polymers, based on carboxylate ions and polyampholytes, (nonionic polymers) which carry both positive and negative charges.

  • Anionic, emulsion grade polymers: A range of high molecular weight anionic water-in-oil emulsions. These chemical products are suitable for in-line dilution before being added to the application.
  • Cationic emulsion grade polymers: A range of linear and structured cationic water in oil emulsions. These chemical products are suitable for in-line dilution before being added to the application.
  • Anionic, powder-grade polymers: Anionic powder-grade polymers available in low, medium and high molecular weights.
  • Cationic, powder-grade polymers: Cationic chemical powders available in a range of molecular weights.



When referring to coagulants, positive ions with high valence are preferred. Generally Aluminium  and iron are applied, aluminium as Al2(SO4)3- (aluin) and iron as either FeCl3 or Fe2(SO4)3-. One can also apply the relatively cheap form FeSO4, on condition that it will be oxidized to Fe3+ during aeration.

Coagulation is very dependent on the doses of coagulants, the pH and colloid concentrations. To adjust pH levels Ca(OH)2 is applied as co-flocculent. Doses usually vary between 10 and 90 mg Fe3+/ L, but when salts are present a higher dose needs to be applied

  • Organic primary coagulants including polyamines and PolyDADMACS: High cationic charge products needed to destabilise negatively-charged colloidal particles and promote rapid floc formation. Low molecular weight and viscosity ensuring complete distribution and mixing of the polymer in the water.
  • Inorganic primary coagulants: A wide range of PAC based products; Ferric Sulphate, Ferric Chloride and Alum are available.
  • Anti-foams: Wide range of very effective anti-foam products.



Disinfectants kill present unwanted microrganisms in water. There are various different types of disinfectants:
· Chlorine (dose 2-10 mg/L)
· Chlorine dioxide
· Ozone
· Hypochlorite

Chlorine dioxide disinfection

ClO2 is used principally as a primary disinfectant for surface waters with odor and taste problems. It is an effective biocide at concentrations as low as 0.1 ppm and over a wide pH range. ClO2 penetrates the bacterial cell wall and reacts with vital amino acids in the cytoplasm of the cell to kill the organisms. The by-product of this reaction is chlorite.
Chlorine dioxide disinfects according to the same principle as chlorine, however, as opposed to chlorine, chlorine dioxide has no harmful effects on human health.

Hypochlorite disinfection

Hypochlorite is applied in the same way as chlorine dioxide and chlorine.

Ozone disinfection

Ozone is a very strong oxidation medium, with a remarkably short life span. It consists of oxygen molecules with an extra O-atom, to form O3. When ozone comes in contact with odour, bacteria or viruses the extra O-atom breaks them down directly, by means of oxidation. The third O-atom of the ozone molecules is than lost and only oxygen will remain.

Disinfectants can be used in various industries. Ozone is used in the pharmaceutical industry, for drinking water preparation, for treatment of process water, for preparation of ultra-pure water and for surface disinfection.
Chlorine dioxide is used primarily for drinking water preparation and disinfection of piping.

Every disinfection technique has its specific advantages and its own application area. In the table below some of the advantages and disadvantages are shown:

Technology Environmentally friendly Byproducts Effectivity Investment Operational costs Fluids Surfaces
Ozone + + ++ + ++ ++
UV ++ ++ + +/- ++ + ++
Chlorine dioxide +/- +/- ++ ++ + ++
Chlorine gas + ++ +/-
Hypochlorite + ++ +/-



Hydrolink Technologies Limited provides a wide range of effective antifoaming products to control or eliminate foam with the perfect antifoam solution for your waste water treatment applications, including a variety of effective antifoam agents that let you control foaming caused by chemical, biological and mechanical factors.



Chemical oxidation processes use (chemical) oxidants to reduce COD/BOD levels, and to remove both organic and oxidisable inorganic components. The processes can completely oxidize organic materials to carbon dioxide and water, although it is often not necessary to operate the processes to this level of treatment


pH conditioners

Municipal water is often pH-adjusted, in order to prevent corrosion from pipes and to prevent dissolution of lead into water supplies. During water treatment pH adjustments may also be required. The pH is brought up or down through addition of basics or acids. An example of lowering the pH is the addition of hydrogen chloride, in case of a basic liquid. An example of bringing up the pH is the addition of natrium hydroxide, in case of an acidic liquid.
The pH will be converted to approximately seven to seven and a half, after addition of certain concentrations of acids or basics. The concentration of the substance and the kind of substance that is added, depend upon the necessary decrease or increase of the pH.


Enzymes and Catalysts

Hydrolink provides a wide range of enzymes applied in waste water treatment systems to reduce on COD/BOD, Odour control, excessive sludge accumulation and fats and oil digestion.



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