Mwenda Bertha Kinya2026-04-162026-04-162015https://repository.chuka.ac.ke/handle/123456789/22541A Thesis Submitted to the Graduate School in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science in Chemistry of Chuka University Supervisors: Prof. Eric Njagi,Prof. Moses Muhungu MurayaWater quality is a pressing global concern, since water pollution negatively impacts water bodies and poses severe threats to both human and aquatic life.The aim of this study was to, determine physico-chemical and bacteriological parameters of Nguue spring and river Mutonga, and compare to the limits set by WHO and KEBS. The performance of low-cost adsorbent in removal of zinc and iron from contaminated water was also evaluated. Sampling was done each at six points along the river and the spring approximately 500 metres apart, in the dry and wet season in the months of September and November 2024. The physical parameters of water such as temperature, pH, DO, TDS and EC were measured using multiparameter. Total hardness was estimated by titrimetry. Anions of NO3 - and PO4 3- were determined by UV spectrophotometric method. The heavy metals of Zn2+ and Fe3+ in water samples were determined by Atomic Absorption Spectrophotometer. In the dry season, River Mutonga recorded a temperature between 25.9-26.6 °C, pH of 7.1-7.4 , electrical conductivity was 172.8-202 µS/cm, total dissolved solids 0.838-0.886 mg/L , dissolved oxygen, 3.19-3.25 mg/l, however, total hardness 0.838-0.886 mg/L, nitrate concentrations 16.57-19.35 mg/L, while phosphate was 1.95-2.12 mg/L. Nguue Spring during the dry season exhibited a temperature of 25.9-26.5 °C, pH was 5.21-6.58 indicating slight acidity, electrical conductivity of 147.6-193.6 µS/cm and total dissolved solids 0.552-1.2 mg/L, total hardness wa 58-160 mg/L, well Similar to Mutonga River, nitrate levels 16.83-19.47 mg/L. In the wet season, River Mutonga recorded a lower temperature of 21 °C compared to the dry.4 and 6.5-8.5 respectively, indicating increased acidity in sampling point M1. Electrical conductivity 57.2-60.4 µS/cm and total dissolved solids 31.3-36.6 mg/L were markedly lower than in the dry season, reflecting dilution effects of rainfall. Dissolved oxygen was 8.72-8.92 mg/L increased substantially and was well above the WHO minimum standard 4.0 mg/l. Total hardness decreased to 87.3-122 mg/L but remained within permissible limits. Nitrate levels dropped to 7.25-12.35 mg/L, now falling within KEBS standards which is 10 mg/l, while phosphates was 2.01-2.29 mg/L remained above WHO limits 0.5 mg/L. Nguue Spring in the wet season showed a temperature of 20.5-21 °C, pH was4.210-5.724 was consistently below both WHO and KEBS ranges, suggesting acidic conditions. Electrical conductivity was 37.8-55.6 µS/cm and total dissolved solids 27.7-59.5 mg/L decreased compared to the dry season, reflecting rainwater dilution. Dissolved oxygen was 8.58-8.86 mg/L was significantly elevated and met WHO standards, total hardness was 22.6-84 mg/L remained within permissible limits. Nitrate concentration was 7.8-14.65 mg/Lwas marginally above the KEBS guideline, while phosphate was 1.95-2.23 mg/L exceeded WHO standards but was acceptable under KEBS. Batch adsorption was carried out by varying the parameters of temperature, pH, intial concentration, contact time and adsorbent dosage. The total coliforms count in Mutonga were 11-460 and 36-1100 MPN per 100 ml in dry and wet season repectively and exceeded KEBS and WHO limits. In Nguue spring the toal coliform counts were 36-1100 and 43-˃1100 MPN per 100 ml in dry and wet season respectively exceeding KEBS and WHO limits. Adsorption of zinc and iron on CCAC and CCC was successfully represented by Freundlich and Lngmuir isotherm models. Adsorption of zinc on CCAC and CCC was best described by Freundlich with KF=2.35 mg/g, n=1.387, R2=0.9359 and KF=116.84mg/g, n=0.1634, R2= 0.9497 respectively indicating a favourable multilayer adsorption on heterogenous surface. Adsorption of iron on CCAC and CCC also Freundlich gave a reasonable fit with KF=1.1498mg/g, n=0.5826, R2=0.90703 and KF=1.8034mg/g, n=0.9063, R2=0.97692 respectivelyenWater quality assessmentCorn-cob carbon adsorbentHeavy metal removalAdsorption isothermsBacteriological contaminationWater remediationKenyaThesis