Chebude, Yonas (PhD)Rebuma, Mekwanint2022-05-252023-11-182022-05-252023-11-182021-09-02http://etd.aau.edu.et/handle/12345678/31799Effluents from the paint industry have been a major source of environmental pollution. The paint industry generate wastewater, primarily due to cleaning operations of mixers, reactors, blenders, packing machines and floors. There is a need to investigate the compliance of wastewater discharged from paint industries with regulatory standards. In response, this study evaluates the physicochemical parameters of both raw and treated wastewater, the wastewater treatment plants (WWTPs) efficiencies as well as the compliance level of three selected paint manufacturing companies in Addis Ababa, Ethiopia, with some regulatory standards: Ethiopian Standard and World Health Organization (WHO). A study on the impact of a paint industry effluents on the vegetables solanum lycopersicum (tomato) and D. carota (carrot) was also carried out. Analysis of physico-chemical and heavy metal parameters of selected paint factories’ samples in Kadisco (CA), Zemilli (ZE), and Nifas Silk (NS) were performed to investigate the concentration of status of the parameter. In this study, physicochemical and heavy metal parameters such as pH, TDS, EC,COD, BOD, PO43-, NO3-, SO42+, NH3, NH4+, Cr+6,Zn+2, Cd and Pb of the fourteen wastewater samples were analyzed using, standard methods. The values of pH, electrical conductivity (EC) and total dissolved solids (TDS) levels were in the range of 6.80-8.50, 858.00 - 2540.00 mS/m and 410.00- 1270.00 mg/L, respectively. The range of other parameters include ammonia; 0.35-0.42mg/l, biological oxygen demand (BOD); 6.40 – 35.76mg/L, chemical oxygen demand (COD); 283.00–485.0 mg/L, nitrates; 0.68-12.50 mg/L, phosphate; 1.31-1.52, sulfate; 32.33–188.33 mg/L, lead; 0.01–0.06 mg/L, zinc 0.01-0.02 mg/L while cadmium and chromium were below detection limits. The results indicated that the WWTPs of the studied paint factories were ineffective in reducing the pH, TDS, and EC to acceptable limits. Wastewater samples were collected from two paint factories (Kadisco paint and Nifas Silk paint factory) and their impacts on the germination and growth of (vegetables solanum lycopersicum (tomato) and D. carota (carrot)) have been studied. The obtained results revealed that wastewater from Cadisco paint factory did not affect seed germination except a minor inhibition in solanum lycopersicum (tomato). Effluents from Nifas Silk factory stimulated seed germination in both solanum lycopersicum (tomato) and D. carota (carrot). It can be concluded that paint factories wastewater may have different effects on growth of different vegetables, depending up on the nature of wastewater and sensitivity of a plant species to wastewater.enWastewater TreatmentPaint IndustriesPercentage EfficiencyGermination Percentage Plant GrowthThesis