Characterization of greywater sources on the base of organic content and microbial quality

Abstract

Abstract The recycling of greywater for non-potable water applications, such as toilet flushing or irrigation, is a potential solution to reduce potable water consumption. To estimate the quality of raw greywater samples, we measured several physical, chemical and biological parameters. We used Hygiene Monitor test kits to determine microbiological presence in the samples. The greywater samples showed a high variability for all the measured parameters. In general, we found that greywater sources had lightly alkaline character with a considerable inorganic and organic content. About half of the analyzed samples can be characterized as highly contaminated water source with organic substance. The average BOD5 and DOC values of greywater samples were 429 ± 410 mg l−1 and 341 ± 348 mg l−1. The samples showed high similarity concerning the total plate counts parameter (range from 5 to 6 log10 cfu ml−1). Among the three greywater sources, the samples from dish sources showed the lowest coliform content (3.9 log10 cfu ml−1) and the bath samples were contaminated with coliforms to the highest degree (4.9 log10 cfu ml−1). The results of E. coli contamination tests proved that all greywater sources can be contaminated with pathogen bacteria, consequently the treatment before reuse of greywater is indispensable.