Assessment of Effects of Brewery Waste Water Discharge and Self Purification Potential of “Rafin Giya” Stream in Kudenda Industrial Layout, Kaduna Nigeria

Flowing surface water bodies have natural capacities to purify themselves from pollutions that come into them from external sources. The impact of the effluents of a brewing industry located in Kaduna on Rafin Giya stream and its self-purification potential were investigated. The brewery wastewater effluents were collected and analysed for some physicochemical parameters for a period of 27 days to determine the level of constituents, toxicity level and suitability for its discharge into receiving water body. Water samples were also collected from five points at 200 m interval along the stream covering the upstream and the downstream. The physicochemical parameters determined include: pH, Temperature, Electrical conductivity (EC), Turbidity, Total suspended solids (TSS), Total dissolved solids (TDS), Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Chlorides and Coliform. The average values of these parameters for the brewery effluents were 3.79, 29.09°C, 1011.8 µs/cm, 6.09 NTU, 1048.9 mg/L, 826.9 mg/L, 1128.8 mg/L, 2122.1 mg/L, 573.5 mg/L and 1 MPN in respectively. Most of these parameters were found to be higher than the limits set by the National Environmental Standards and Regulations Enforcement Agency (NESREA) in Nigeria for industrial wastewater discharge into receiving water bodies. The physicochemical parameters determined for the stream water also include: pH, Temperature, Total suspended solids (TSS), Turbidity, Chlorides, Biological Oxygen Demand (BOD5), Dissolved oxygen (DO), Electrical conductivity (EC), Total dissolved solids (TDS) and coliform. The values obtained at a point upstream, the brewery effluent discharge point and three points downstream at 200 m intervals were 6.4, 4.0, 4.8, & 4.9; 27°C, 31°C, 31°C, 31°C, & 30°C; 3.8 NTU, 8.1 NTU, 8.0 NTU, 7.8 NTU, & 7.1 NTU; 730 mg/l, 1490 mg/l, 1420 mg/l, & 1340 mg/l; 270 µs/cm, 1480 µs/cm, 1480 µs/cm, 1450 µs/cm, & 1400 µs/cm; 100 mg/l, 1680 mg/l, 1550 mg/l, 1430 mg/l & 12000 mg/l; 14.6 mg/l, 2.8 mg/l, 3.9 mg/l, 4.8 mg/l, & 6.4 mg/l, for pH, Temperature, Turbidity, Electrical conductivity, BOD, and DO respectively. The corresponding self-purification potential exhibited by the stream over a distance of study were found to be 76.6%, 90 .0%, 25.0%, 53.5%, 93.7%, 8.3%, 43.8%, 19.3%, 54.5% and 100% for the parameters respectively. This trend of results compare favourably with literature values on flowing rivers. These results therefore suggested that the brewery wastewater have great pollution impact on the stream water and therefore making it unsuitable for human consumption. The pollution absorbance potential of the stream is low as a result of its low volume and flow rate, although gradual self-purification was observed, it is recommended that careless disposal of such contaminants should be discouraged with strict enforcement of existing legislation and regular monitoring.