Grey Water Quantity and Quality Assessment (Case Study: Isfahan University Dormitories)

In this study, the quantity and quality of Grey Water (GW) were surveyed in the dormitories of Isfahan University by the aim of its reuse. For this purpose, the non-potable water consumption (bathing and washing clothes) was monitored in both boys and girls dormitories, where its variations were evaluated daily in the academic semesters (October-November and May-June) alongside its quality. Results showed that the average daily GW production of students is 111 liters per capita per day, in which by considering 4400 residents in the dormitories, this wastewater can supply at least 10% of the water required for the irrigation of campus green areas. It was also indicated that the daily average grey water production of girls' dormitories per capita was significantly higher about 20% than boys’. In addition, the daily grey water production per capita of students on weekends was significantly higher than the other days about 16%. Based on these data, the daily and hourly peak coefficients of grey water production were about 1.16 and 1.25, respectively. The quality analysis of discharged grey water showed that the average concentrations of BOD, COD and TSS were 65, 142 and 52 mg/L, respectively, which has a relatively low biodegradability and suspended solids.