Effluent

About: Effluent is a research topic. Over the lifetime, 32668 publications have been published within this topic receiving 533991 citations.

Replacement of chemical oxygen demand (COD) with total organic carbon (TOC) for monitoring wastewater treatment performance to minimize disposal of toxic analytical waste

Abstract: Chemical oxygen demand (COD) is widely used for wastewater monitoring, design, modeling and plant operational analysis. However this method results in the production of hazardous wastes including mercury and hexavalent chromium. The study examined the replacement of COD with total organic carbon (TOC) for general performance monitoring by comparing their relationship with influent and effluent samples from 11 wastewater treatment plants. Biochemical oxygen demand (BOD5) was also included in the comparison as a control. The results show significant linear relationships between TOC, COD and BOD5 in settled (influent) domestic and municipal wastewaters, but only between COD and TOC in treated effluents. The study concludes that TOC can be reliably used for the generic replacement of both COD (COD=49.2+3.00*TOC) and BOD5 (BOD5=23.7+1.68*TOC) in influent wastewaters but only for COD (COD=7.25+2.99*TOC) in final effluents.

Environmental performance of wastewater treatment plants for small populations

Abstract: Life cycle assessment (LCA) is an environmental tool which allows the calculation of all the environmental loads related to a process/product/service. In the present work, LCA was applied to analyze the environmental impact of different technologies for wastewater treatment in small populations. In this study, 13 wastewater treatment plants (WWTPs) of less than 20,000 population equivalent (p.e.) located in Galicia (NW Spain) were inventoried. The results of the evaluation of the environmental impact are expressed in terms of diverse impact categories. Normalization identified eutrophication, mainly as P-PO43−, N-NH4+ and organic load as chemical oxygen demand (COD) in the treated effluent, and terrestrial ecotoxicity, due to the heavy metals content in the sludge, as the most significant categories for all WWTPs. Electricity use plays an important role in five of seven impact categories and presents the highest importance in four of them. When comparing technologies, secondary treatment technologies such as biodenipho and aerobic–anoxic treatment resulted in a lesser environmental impact than extended aeration. The operation of the plants has large contribution on the impact, especially for those that make use of extended aeration.

Use of the Chiral Pharmaceutical Propranolol to Identify Sewage Discharges into Surface Waters

Abstract: The discharge of relatively small volumes of untreated sewage is a source of wastewater-derived contaminants in surface waters that is often ignored because it is difficult to discriminate from wastewater effluent. To identify raw sewage discharges, we analyzed the two enantiomers of the popular chiral pharmaceutical, propranolol, after derivitization to convert the enantiomers to diastereomers. The enantiomeric fraction (the ratio of the concentration of one of its isomers to the total concentration) of propranolol in the influent of five wastewater treatment plants was 0.50 ± 0.02, while after secondary treatment it was 0.42 or less. In a laboratory study designed to simulate an activated sludge municipal wastewater treatment system, the enantiomeric fraction of propranolol decreased from 0.5 to 0.43 as the compound underwent biotransformation. In a similar system designed to simulate an effluent-dominanted surface water, the enantiomeric fraction of propranolol remained constant as it underwent biotran...