Such residues are also present in conventional wastewater treatment effluent. PCB is a global pollutant and was measured in the wastewater effluent from paint production. Constructed wetlands can be used to treat raw sewage, storm water, agricultural and industrial effluent. Therefore they find most of their uses in liquid effluent (wastewater) treatment. It is also used to clean effluent and brackish groundwater. They also collect charges for abstraction and effluent discharges. Numbers have been known to gather near discharges of warm effluent from power plants. A grinder pump is different from a sump pump or effluent pump. This results in saturating the pressurized effluent water with air. The fish were exposed to aerated, undiluted, treated effluent. Environmental engineers deal with any air emissions and treatment of liquid effluent. This minimizes the loss of residual food in the treated effluent. Hydrogen can also be produced by refining the effluent from geothermal sources in the lithosphere. These caused better washing, reduced biological oxygen demand (BOD) in effluent and reduced deposits. This bioassay is used in the assessment of the toxicity of complex industrial effluent sources.