Wastewater

About: Wastewater is a research topic. Over the lifetime, 92512 publications have been published within this topic receiving 1256590 citations. The topic is also known as: waste water.

Modelling the urban water cycle

Abstract: Current urban water management practices aim to remove stormwater and wastewater efficiently from urban areas. An alternative approach is to consider stormwater and wastewater as a potential resource substitute for a portion of the water imported via the reticulated supply system. A holistic view of urban water resources provides the framework for the evaluation of the demand for water supply, the availability of stormwater and wastewater, and the interactions between them. The water balance model (Aquacycle) developed in this study represents water flows through the urban water supply, stormwater, and wastewater systems. Its daily time step provides temporal distribution of the flows, and enables comparison of the different components of the urban water demand. Aquacycle was tested using data from the Woden Valley urban catchment in Canberra, Australia and found able to satisfactorily replicate its water supply, stormwater and wastewater flows. Crown Copyright  2001 Published by Elsevier Science Ltd. All rights reserved.

Occurrence and fate of the cytostatic drugs cyclophosphamide and ifosfamide in wastewater and surface waters.

Abstract: The two oxazaphosphorine compounds cyclophosphamide and ifosfamide are important cytostatic drugs used in the chemotherapy of cancer and in the treatment of autoimmune diseases. Their mechanism of action, involving metabolic activation and unspecific alkylation of nucleophilic compounds, accounts for genotoxic effects described in the literature and is reason for environmental concern. The occurrence and fate of cyclophosphamide and ifosfamide were studied in wastewater treatment plants (WWTPs) and surface waters in Switzerland, using a highly sensitive analytical method based on solid-phase extraction and liquid chromatography tandem mass spectrometry. The compounds were detected in untreated and treated wastewater at concentrations of <0.3-11 ng/L, which corresponded well with concentrations predicted from consumption data and typical renal excretion rates. Weekly loads determined in influent and effluent wastewater were comparable and suggested a high persistence in WWTPs. Furthermore, no degradation was observed in activated sludge incubation experiments within 24 h at concentrations of approximately 100 ng/L. Processes that may be relevant for elimination in natural waterbodies were studied with a set of incubation experiments in the laboratory. After extrapolation to natural conditions in surface waters, a slow dark-chemical degradation (half-lives on the order of years) is the most important transformation process. Degradation by photochemically formed HO* radicals may be of some relevance only in shallow, clear, and nitrate-rich waterbodies but could be further exploited for elimination of these compounds by advanced oxidation processes, i.e., in a treatment of hospital wastewater. In surface waters, concentrations ranged from < or =50 to 170 pg/L and were thus several orders of magnitude lower than the levels at which acute ecotoxicological effects have been reported in the literature (mg/L range). However, due to a lack of studies on chronic effects on aquatic organisms and data on occurrence and effects of metabolites, a final risk assessment cannot be made.