Domestic greywater flows and pollutant loads: A neighbourhood study within a university campus in Ghana

Domestic greywater management is a challenge and remains the most neglected sanitation component in Ghana. Meanwhile, data on greywater (quantity and quality) is very limited. This paper aimed to generate relevant information on greywater using a residential neighbourhood within a university campus in Kumasi city. Data was generated from five households of 24 inhabitants using interviews, greywater quantification by volumetric flow measurement, and laboratory analyses. Greywater flows collected from bathrooms, kitchen, laundry and sink sources were between 250 and 260 l/h/d (52 – 54 l/c/d). Major contaminants like turbidity (270 NTU), TSS (180 – 190 mg/L), BOD5 (320 – 350 mg/L), COD (690 – 740 mg/L), TP (3 mg/L), NH3N/NH4+ (6 – 12 mg/L), and Hg & Pb (0.3 – 0.8 mg/L) failed the regulatory discharge limits. Anionic surfactants (6 – 7 mg-LAS/L), SO42− (13 – 15 mg/L), sodium absorption ratio (SAR, 0.6 (meq/l)½) and biodegradability ratio (BOD5/COD, 0.5) were also determined. Specific pollutant loads were comparable to available literature, e.g. BOD5 & COD were about 18 g/c/d and 38 g/c/d respectively. The untreated greywater flows are low, loaded with pollutants and considered unsafe for open discharge into the environment without treatment.