Freezing Technology

Teriority Treatment

Tertiary Treatment

            Tertiary treatment is also known as advanced waste water treatment. It is an additional treatment needed to remove suspended and dissolved substances remaining after conventional primary and secondary treatment. The available processes comprise micro-straining, chemical precipitation, sand filtration, ion exchange, carbon absorption, reverse osmosis, ozone oxidation etc. Except in the case of water reuse system, these systems are not widely in use, since the cost involved is quite high. In the case of seafood wastewater, the secondary treatment generally provides acceptable effluent.

Disinfection: Disinfection is carried out after the wastewater undergoes treatment so that there will be minimum organic matter left to interfere with disinfecting process. The techniques available include chlorination, and treatment involving ozone, iodine, bromine, UV, gamma, X-ray, micro waves and physical methods like ultra-sonic disruption and heat. Chlorine is the cheapest method of disinfection but it imparts carcinogenic residues. Many algae, spore formers and viruses are known to survive chlorination. In moderate volume UV radiation is effective in killing micro organisms leaving no residue.

Disposal of waste: There are three options available for the discharge of treated or raw effluent generated from finfish and shellfish processing and freezing plant. These are a) into public sewage system, b) into the environment (streams, river, lakes, sea, land etc.,) and c) for land application. In India, many plants are located in thinly populated areas where there are no public sewage systems. Hence, it becomes necessary to discharge the effluent into the environment after treating according to the norms. Some options available for the disposal of solid waste generated in treatment process along with grit and sludge are land filling, burying (in the case of small plant), incineration (in the case of large plant), disposal into municipal solid waste and macerating to return into waste water system again.