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The greywater characterization involved assessment of the main use physicochemical and microbial parameters and selected organic micropollutants. The physicochemical qualities are provided in Tables 4 and 5 for the two study sites used. The findings from the two sites are similar when compared against the Ghana Environmental Protection Agency (GEPA) draft guidelines for wastewater discharges (GEPA n.d.). Most greywater discharges from almost all sources are failing according to GEPA standards in almost all parameters. With pH and electrical conductivity (EC), most sources met GEPA standards but one or two discharge sources failed marginally (Tables 4 and 5). Moreover, attention should be given to key parameters such as nutrient (nitrogen and phosphorus) levels and BOD/COD ratio to reduce the impact on the receiving aquatic environment. The higher BOD and COD levels coupled with very low BOD/COD ratios (far less than 0.5, i.e. 0.20 ± 0.07) challenge biodegradation (Kulabako et al. 2011; Boyjoo et al. 2013), especially under natural environmental self-purification conditions. The very low biodegradation observed is similar to studies from Uganda with mean BOD/COD ratio range of 0.13–0.25 (Kulabako et al. 2011), and in low income communities of Accra, Ghana, with BOD/COD ratio of 0.29, but for high and middle income communities the BOD/COD ratios were more than 0.80 (Mohammed et al. 2015). Thus, greywater composition can be highly variable depending on household activities, lifestyle and use of chemicals (Etchepare & van der Hoek 2015). Also, the nutrients are far in excess of the GEPA limits, by 12 times (P) and 30 times (N), signalling caution regarding potential algal bloom and eutrophication in receiving water bodies. However, the nutrient characteristics offer great potential for reuse in irrigation because they fall well within the recommended limits of 2–32 mg/l (N) and 0.6–27 mg/l (P) (Mohamed et al. 2013).

Table 4

Physicochemical parameters of greywater from Bomso

ParameterUnitsGhana EPA guidelinesCompositeLaundryBathroomKitchenSalon
pH – 6–9 7.8 9.1 6.8 8.8 6.4 
EC μS/cm 1,500 1,147 3,530 1,148 3,130 374 
TSS mg/l 50 2,360 3,610 476 4,720 372 
Turbidity NTU 75 386 729 549 528 532 
BOD mg/l 50 248.3 268.5 139.3 269 132.5 
COD mg/l 250 1,510 2,210 400 2,180 580 
BOD/CODw – NA 0.16 0.12 0.35 0.12 0.23 
Total Kjeldahl nitrogen mg/l 1.0b 13.7 12.8 7.7 14.5 8.1 
Mg mg/l NA 1.72 0.52 1.94 5.67 1.74 
Total P mg/l 13.2 12.2 11.3 13 22.6 
ParameterUnitsGhana EPA guidelinesCompositeLaundryBathroomKitchenSalon
pH – 6–9 7.8 9.1 6.8 8.8 6.4 
EC μS/cm 1,500 1,147 3,530 1,148 3,130 374 
TSS mg/l 50 2,360 3,610 476 4,720 372 
Turbidity NTU 75 386 729 549 528 532 
BOD mg/l 50 248.3 268.5 139.3 269 132.5 
COD mg/l 250 1,510 2,210 400 2,180 580 
BOD/CODw – NA 0.16 0.12 0.35 0.12 0.23 
Total Kjeldahl nitrogen mg/l 1.0b 13.7 12.8 7.7 14.5 8.1 
Mg mg/l NA 1.72 0.52 1.94 5.67 1.74 
Total P mg/l 13.2 12.2 11.3 13 22.6 

NA, not available; bammonia level; w0.20 ± 0.09.

Table 5

Physicochemical parameters of greywater from Ayigya

ParametersUnitsGhana EPA guidelinesCompositeLaundryBathroomKitchen
pH – 6–9 8.2 9.6 6.8 9.7 
EC μS/cm 1,500 1,045 351 1,544 863 
TSS mg/l 50 1,820 2,170 440 3,020 
Turbidity NTU 75 378 400 342 204 
BOD mg/l 50 265.3 258.5 205.3 249.5 
COD mg/l 250 1,260 1,410 840 1,860 
BOD/CODw – NA 0.21 0.18 0.24 0.13 
Total Kjeldahl nitrogen mg/l 1.0b 16.3 15.4 23.9 29.5 
Mg mg/l NA 0.33 1.00 0.88 1.05 
Total P mg/l 18.5 23.2 12.5 10.8 
ParametersUnitsGhana EPA guidelinesCompositeLaundryBathroomKitchen
pH – 6–9 8.2 9.6 6.8 9.7 
EC μS/cm 1,500 1,045 351 1,544 863 
TSS mg/l 50 1,820 2,170 440 3,020 
Turbidity NTU 75 378 400 342 204 
BOD mg/l 50 265.3 258.5 205.3 249.5 
COD mg/l 250 1,260 1,410 840 1,860 
BOD/CODw – NA 0.21 0.18 0.24 0.13 
Total Kjeldahl nitrogen mg/l 1.0b 16.3 15.4 23.9 29.5 
Mg mg/l NA 0.33 1.00 0.88 1.05 
Total P mg/l 18.5 23.2 12.5 10.8 

NA, not available; bammonia level; w0.19 ± 0.05.

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