RC. 497 339
WATER TREATMENT TECHNOLOGY AND CHEMICAL COMPANY (NIGERIA) LIMITED
Potable, Process & Waste Water Treatment Solutions
Sodium Hypochlorite (NaOCl)
NaOCl, also known as liquid bleach, is a chemical compound that adds chlorine to water. When added to water, NaOCl undergoes a chemical reaction that forms hypochlorous acid (HOCl) and hypochlorite ion (OCl-). The sum of HOCl and hypochlorite ions is free available chlorine (FAC), which acts as a disinfectant.
NaOCl + H2O → HOCl + NaOH
HOCl ↔ H+ + OCl-
The main advantage of selecting NaOCl over chlorine gas is that the disinfectant is produced and stored in liquid form eliminating the danger of large scale gas leaks from high pressure chlorine cylinders. Gaseous chlorine reacts as an acid, whereas hypochlorite solutions tend to be slightly alkaline. Because gaseous Cl2 has low pH, it depresses the pH of drinking water. On the other hand, the pressure of caustic soda in Sodium hypochlorite increases the water’s pH. The difference exists only at the point of disinfectant application and when the chemicals are blended in the water. There isn’t a significant change in the finished water’s pH.
Sodium hypochlorite has long been recognized as having outstanding disinfection properties.
For industrial and institutional applications the versatility and usefulness of sodium hypochlorite include:
· It is used extensively in the area of water treatment to disinfect municipal drinking water.
· It controls algae in open reservoirs.
· It remains as one of the most effective, and certainly the most cost-effective means of controlling the zebra mussel population, the presence of which is causing serious problems for industry and the ecosystem.
· It is widely used for swimming pool water disinfection, both as a daily regimen and as a shock treatment.
· It is used to treat sewage to reduce odours and increase digesting efficiency.
· Odour control in industrial wastes.
· Cyanide waste treatment in metal finishing and gold mining.
· Air scrubbing.
· Food processing: dairy equipment sanitizing, fruit and vegetable processing, mushroom production, hog, beef and poultry production, maple syrup production, fish processing.
· Precious metal recovery.
· Cooling water and boiler water treatment to prevent fouling.