Pollution control is considered as end-of-pipe solution. Priority should always be on waste minimisation through water reuse or conservation, so as to reduce wastewater generation. Key water quality parameters includes: Suspended Solids, Turbidity, BOD, COD, TDS, etc.
Preliminary Treatment
Consists of screenings, grit chambers to remove large debris, objects, grit (heavy solids like sand/gravel) that may damage pumping equipment & water pipes/channels in treatment plant. Depending on the wastewater characteristics, equalization & neutralization may also be done.
Primary Treatment
Consists of primary sedimentation, flotation or filtration to remove majority of suspended solids, oil & grease. The effluent from the primary treatment still contains a high level of BOD.
Secondary Treatment
Consists of biological processes, which help to remove organic matter with the help of bacteria, either in an aerobic or anaerobic condition. Commonly used aerobic processes include the activated sludge process and trickling filters.
Tertiary Treatment
Additional treatment that follows primary and secondary treatment processes, employed when primary and secondary treatment cannot accomplish all that is required. Examples include disinfection or additional filtration to reduce TSS to meet discharge limits.
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