Wastewater Regulation Wastewater Treatment

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2.2.1 Wastewater Regulation

Development and implementation of wastewater treatment is the answer for the concern for public health and unpleasant condition caused by the discharge of wastewater to the environment [22 – 23]. Removal of suspended and floatable material, treatment of biodegradable organics and other contaminants, as well as elimination of pathogenic organism are the basic principle of the water treatment process. USEPA Water Pollution Control Act of 1972 established the standards for wastewater discharge. Secondary treatment such as removal of suspended solid and biodegradable organics, as well as disinfectant of municipal wastewater must be treated to meet the acceptable levels before releasing into the environment. USEPA and most of other countries’ regulation for water pollution insists the industries to use the best available technology to treat their wastewater before its disposal. The admissible maximum values of contaminants in the treated wastewater of different countries are regulated according to their own guidelines. The Malaysian standard for industrial effluents is presented in Table 2.1. Table 2. 1 Malaysian effluent standard regulation for sewage and industrial effluents, Environmental Quality Act 1974 [Laws of Malaysia; act 127 1999] [24]. Parameters Unit Standard A Standard B Temperature ˚C 40 40 pH value - 6.0 – 9.0 5.5 – 9.0 BOD 5 at β0˚C mgL 20 50 COD mgL 50 100 Suspended Solids mgL 50 100 Phenol mgL 0.001 1.0 Free chlorine mgL 1.0 2.0 Sulphide mgL 0.50 0.50 Ammoniacal Nitrogen mgL 10 20 Oil and grease mgL 1.0 10 13 Some more stringent standards have been developed recently to deal with the removal of nutrients and the priority pollutants. When the wastewater is to be reused, standards normally include the requirements for the removal of refractory organic, heavy metals, and in some cases dissolved solids [22]. Hence, in order to achieve the regulation standard, the effluents from the industries have to be treated appropriately before discharging into the environment.

2.2.2 Wastewater Characteristics