title: Improving the sensitivity of the activated sludge respiration inhibition test and verifying the results using an oxidation-reduction potential electrode.
abstract: The inhibition of activated sludge respiration is one of the most important parameters for monitoring wastewater toxicity. The main objective of this study was to improve respiration inhibition testing in order to protect the biological degradation within the aerobic process in a wastewater treatment plant more efficiently. In order to influence the sensitivity of the testing bacteria, two different nutrient solutions were selected for biological testing, synthetic wastewater according to ISO 8192 and NaAc (sodium acetate). The effects of the nutrient solutions on heavy metal speciation and their respiration inhibition were investigated. The toxicants Zn(II), Cu(II), Cr(VI) and 3,5 DCP (3,5-dichlorophenol) were used as standards to determine toxicities and to study the influence of nutrient solutions. Results have shown that NaAc as a nutrient solution sensitized the respiration inhibition test up to a factor of 7.7. Furthermore, an oxidation reduction potential electrode can be used as an alternative tool to verify the results obtained with an oxygen sensor.
authors.affiliation: VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Ha Noi, Vietnam; Research and Development Department, LAR Process Analysers AG, Neuköllnische Allee 134, Berlin 12057, Germany E-mail: wgenthe@LAR.com.
authors.forename: F
authors.initials: F
authors.lastname: Friedrichs
authors.affiliation: IEEM gGmbH - Institute of Environmental Engineering and Management at Witten/Herdecke University, Alfred-Herrhausen-Str. 44, Witten 58455, Germany.
authors.forename: K U
authors.initials: KU
authors.lastname: Rudolph
authors.affiliation: VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Ha Noi, Vietnam.
authors.forename: Bich Hanh
authors.initials: BH
authors.lastname: Nguyen
authors.affiliation: IEEM gGmbH - Institute of Environmental Engineering and Management at Witten/Herdecke University, Alfred-Herrhausen-Str. 44, Witten 58455, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Meinardi
authors.affiliation: Research and Development Department, LAR Process Analysers AG, Neuköllnische Allee 134, Berlin 12057, Germany E-mail: wgenthe@LAR.com.
authors.forename: W
authors.initials: W
authors.lastname: Genthe
authors.affiliation: VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Ha Noi, Vietnam.
authors.forename: D Q
authors.initials: DQ
authors.lastname: Trung
mesh_terms: D001419:Bacteria; D004566:Electrodes; D019216:Metals, Heavy; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D019216:Metals, Heavy; D012722:Sewage