Greywater Characteristics In Rural Areas of the Sahelian Region for Reuse Purposes: The Case of Burkina Faso

Abstract

The characteristics of greywater generated in two rural areas (“Barkoundba” and “Kologoudiessé”) located in the Sahelian region in Burkina Faso were assessed through observations in selected concessions, sample collection and laboratory analyses. The study aimed at characterizing the qualitative and quantitative characteristics of greywater in order to evaluate its reuse potential for gardening in rural areas. The results showed that greywater is generated from 3 to 4 main sources with average daily productions of 8 ± 1 L•capita‑1•d‑1 in “Barkoundba” and 13 ± 3 L•capita‑1•d‑1 in Kologoudiessé”. Despite these low rates, the average quantity of greywater production varied from 67 to 344 L•concession‑1•d‑1 during the dry season. This greywater can be collected to provide additional water for irrigation in home gardens of size varying from 10 to 43 m2. Shower activity is the major contributor of greywater with up to 56% in “Barkoundba” and 70% in “Kologoudiessé”. The qualitative assessment of the greywater streams showed that every source is contaminated with chemicals and microbial pollutants at levels not suitable for direct reuse in agriculture. Therefore, it is recommended to treat the greywater before its use for irrigation purposes. Based on World Health Organization (WHO) reuse guidelines, the treatment system should be able to remove bacteria by more than 2 log units and 4 log units if restricted and unrestricted irrigation are considered respectively. Since shower greywater is directly poured onto the ground, the treatment unit should be adapted to the shower room to allow shower greywater collection, in order to collect the required quantities for gardening. A slanted soil treatment system could be investigated. Hazards of a direct reuse are discussed for soils, plants and human health on the basis of the various qualitative parameters. However, an accurate risk assessment would require further investigations with the evaluation of the interannual variability of greywater quality.

Greywater Treatment by High Rate Algal Pond under Sahelian Conditions for Reuse in Irrigation

“…The presence of phosphates and nitrates in greywater has been attributed to detergents and washing powders [16]. The nutrient content in the influent is in the range of reported values from Burkina Faso [15]. (Table 1; Figure 5).…”

“…The values were varying from 14 to 88 mg/L for SS, 65 to 170 mg/L for BOD 5 and 145 to 958 mg/L for COD ( Table 2). In rural area, for shower, laundry and dishwashing greywater, mean values of 1093 to 3060 mg/L, 533 to 2743 mg/L and 1240 to 6497 mg/L have been reported for SS, BOD 5 and COD respectively [15]. This situation could find an explanation in the effect of dilution due to the differences in amounts of water used to perform the activities.…”

“…The authors highlighted that, in areas with water scarcity and rudimentary forms of water supply, water consumption varies from 20 to 30 L/capita/day whereas a household member in a richer area with piped water may generate several hundred liters per day [16]. Mean water consumption of 11 and 24 L/capita/day with a greywater production of 8 and 13 L/capita/day have been reported in rural area in Burkina Faso [15] whereas water consumption in France was estimated at 150 L/capita/day. Figure 3(a) shows the distribution of the pH in the influent (I1), the HRAP (HRAP) and the effluent (EF).…”

Investigating the capacity of hydroponic system using lettuce (Lactuca sativa L.) in the removal of pollutants from greywater while ensuring food security

“…On the other hand, the results of pollutant load analysis in the raw greywater showed that the mean values of TSS, COD and BOD5 was 416.67 mg/L, 346.33 mg/L and 216.47 mg/L, respectively, and was relatively higher as compared those of treated greywater. However, these pollutant loads were less polluted in terms of organic matter pollution than mixed laundry-dishwashing greywater (SS = 1230 mg/L, COD = 3916 mg/L and BOD5 = 1375 mg/L) reported by Maiga et al (2014). BOD and COD concentrations in greywater strongly depend on the amount of water and products (especially detergents, soaps, oils and fats) used in the household (Morel and Diener, 2006).…”

“…The mean values in the raw dishwashing greywater were from 2.78× 10 5 CFU/100 mL, 1.15 × 10 5 CFU/100 mL for E. coli and fecal coliforms, respectively (Table 1). The highest values of up to 2.3 × 10 7 CFU/100 mL for E. coli and up to 3 × 10 7 CFU/100 mL for fecal coliforms have been reported from dishwashing of household in rural area (Maiga et al, 2014). Fecal contamination in dishwashing greywater is due to contaminated vegetables and raw meat used during the cooking process (Ottosson, 2003).…”