Possibilities of water pollution in Cheche and Mtilikwe rivers by stillage from Triangle

Abstract

The main aim of this project was to perform an investigation on the possible impact of Triangle limited stillage on Cheche and Mtilikwe river water quality. This was done by measuring physico- chemical parameters and heavy metals that affect water quality. Samples along Cheche and Mtilikwe rivers were taken from five different positions which are roughly five kilometres apart. Stillage samples were taken from the stillage ponds which stores stillage as it comes directly from the mill before it is used for irrigation purposes. The Control samples were taken from a point in Mtilikweriver at a position suspected to contain little or no stillage at all. Physico-Chemical parameters PH, conductivity and TDS were measured using a Hanna multi metre. COD was measured using a spectrophotometer at 620nm and BOD5 was determined using a BOD probe. Nitrates, phosphates and sulphates were measured using UV/VIS. Heavy metal content was determined using AAS after digesting the samples using nitric acid- HCL method. The results produced shows that stillage is contributing significantly to the amounts of heavy metals in Cheche and Mtilikwe river water.Stillage was found to have an effect on the levels of heavy metal(Cd, Fe, Pb, Co, Zn and Ni) in Cheche and Mtilikwe river waters as their mean concentrations at different positions were higher than WHO and EMA guidelines. The concentration of Cr was found to be high than WHO at all sampling points except stillage, this show there might an effluent which contributes to the amount of Cr other than Stillage. Cu levels were low as compared to WHO parameters. Results also shows that stillage has no effect on PH, temperature, sulphates and nitrates in Cheche and Mtilikwe rivers and have a greater effect on the levels of Phosphates, COD, BOD, TDS and Conductivity. The researcher concluded that stillage do affect the quality of water in Cheche and Mtilikwe river.