Define Wastewater treatment Processes

The wastewater treatment processes that we design mimic the processes that occur in the nature (for example processes that occur in a flowing river). The designed processes increase the rate of removal and control the process variables so that the effluent standards can be met. Just like the water solids we need to deal with wastewater solids also.

The wastewater solids are classified into inorganic or fixed solids and organic or volatile solids. The inorganic or fixed solids are removed through the screening and sedimentation during the primary sedimentation and the organic or volatile solids are stabilized through biochemical oxidation (activated sludge/trickling filter/other) and removed through sedimentation or clarification (secondary). The solids removed are further treated by a process called sludge digestion (which is mostly anaerobic (containing no oxygen)). Please refer to following Figure and Table for various treatment units included in the typical wastewater treatment.