ENVE 420 Industrial Pollution Control Wastewater Treatment Processes Dr. Aslıhan Kerç

Primary – Secondary Treatment Primary and secondary treatment handle non- toxic wastewaters. If ww contains toxic compounds, they have to be pretreated before these processes.

Primary Treatment Preparation of wastewater for biological treatment Removal of large solids by screening, grit removal Equalization: Levels out the hour to hour variations in flows and concentrations. Spill Pond: Retain slugs of concentrated wastes that could upset the downstream processes.

Primary Treatment Neutralization: Follows equalization. Streams of different pH neutralize each other Oil and grease, SS removal by flotation, sedimentation or filtration

Secondary Treatment Biological degredation of soluble organic compounds Biotreatment: - Aerobic - Anaerobic

In-plant Treatment Necessary for biological treatment. Heavy metals, pesticides pass through primary treatment and inhibit biological treatment. Effective for low volume streams with high concentration of non-degredable materials. Easier to treat a specific pollutant from a small and concentrated stream than a large dilute stream.

In-plant Treatment Precipitation Activated carbon adsorption Chemical oxidation Air or stream stripping Ion exchange Reverse osmosis Electrodialysis Wet air oxidation