MINIMIZING OUTPUTS - TREATMENT

Many methods are available for the treatment of industrial wastewaters . The pollutant concentrations from aquaculture facilities are often l ow, but occur in high flow rates. Consequently, much care must be take n to transfer suitable technology. Of the four main types of treatment unit processes, i.e. biological, chemical, mechanical and gravitation al, the latter two types are most commonly employed in flow-through aq uaculture facilities in Europe. This paper identifies the properties o f the wastewater upon which the units operate, the efficiency of selec ted examples and their suitability for various applications. Relevant strategies are recommended. A combination of screening to remove suspe nded particles, followed by sedimentation to thicken the resulting slu dge appears, at present, to be the most appropriate primary treatment strategy for flow-through facilities. Various other secondary or even tertiary techniques can be employed to further treat the main effluent . These can, however, grove prohibitively expensive in high flow situa tions and can produce negligible improvements in environmental protect ion.