Ara Institute of Canterbury, PO Box 540, Christchurch, 8140, New Zealand.
Institute of Environmental Science and Research, PO Box 29-181, Christchurch, 8041, New Zealand.
Environ Monit Assess. 2016 Aug;188(8):475. doi: 10.1007/s10661-016-5442-9. Epub 2016 Jul 19.
Thirty on-site greywater systems were sampled to determine greywater characteristics and practices in the field. Kitchen greywater was present at eight sites and urine was included at seven sites. These non-traditional sources resulted in significantly higher concentrations of enterococci and 5-day biochemical oxygen demand (BOD5) in greywater. Even with the removal of these sources, the concentrations of microbial indicators indicated high levels of contamination could occur across all greywater sources, including "light" greywater. Using multiple microbial indicators showed that all samples had the potential for faecal contamination. Bacteroidales markers were confirmed in treated greywater and in each greywater source, highlighting the potential for human faecal contamination. Although Escherichia coli was absent in treated greywater recycled to the house, other microbial indicators were present; hence, caution is required in using E. coli concentrations as the sole indicator of microbiological water quality. High BOD5 or total suspended solid concentrations exceeded the levels recommended for effective disinfection. Subsurface irrigation, which is assumed to provide a five-log reduction in exposure, is a suitable reuse option for non-disinfected greywater. Only half the occupants had a good understanding of their greywater systems and 25 % of systems were poorly maintained. Elevated microbial indicator contamination of greywater sludge is a potential hazard during maintenance.
现场采集了 30 个现场灰水系统样本，以确定现场灰水的特征和实际情况。8 个地点存在厨房灰水，7 个地点含有尿液。这些非传统来源导致肠球菌和 5 天生化需氧量（BOD5）在灰水中的浓度显著升高。即使去除了这些来源，微生物指标的浓度仍表明，所有灰水来源（包括“轻度”灰水）都可能发生高度污染。使用多种微生物指标表明，所有样本都有可能受到粪便污染。处理后的灰水和每个灰水来源中都确认存在拟杆菌标记物，突出了人类粪便污染的可能性。尽管回收至房屋的处理灰水中没有大肠杆菌，但存在其他微生物指标；因此，在使用大肠杆菌浓度作为微生物水质的唯一指标时需要谨慎。高 BOD5 或总悬浮固体浓度超过有效消毒推荐的水平。假定地下灌溉可将暴露量减少五个对数级，因此是未经消毒的灰水的合适再利用选择。只有一半的居住者对他们的灰水系统有很好的了解，而且 25%的系统维护不善。在维护期间，灰水污泥中微生物指标污染升高是一个潜在的危险。
