Water Pollution

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Characteristics, disposal methods and management of plastic waste in Watamu, Kilifi County, Kenya
(Egerton University, 2019-04) Gwada, Brenda C.
Plastic waste has been and still is a major challenge and concern globally but more so in the developing countries. Plastic has been shown to impact negatively on marine life more specifically marine animals. Watamu ward, in Kilifi County, Kenya, is an important breeding ground for the critically endangered turtles and is being affected by plastic waste. The aim of this study was to assess the characteristics, disposal methods and management of plastic waste in Watamu, in order to contribute to an understanding of the plastic waste disposal practices in the country. The specific objectives were to characterize the plastic waste in Watamu, as well as their streams. Secondly, the study also assessed the factors influencing level of knowledge, attitude and perception among the general public with respect to plastic waste disposal. Thirdly, the study determined the factors that influence plastic waste disposal methods. Finally, the study assessed and described the existing plastic waste management methods in the study area. A social survey was conducted to characterize plastic waste and determine the existing plastic waste management methods in the study area. Stratified random sampling design was used to divide the population of Watamu into groups based on their sub-locations and simple random sampling was used to arrive at the sample for this study. Primary data were collected using observation, structured questionnaire and semi-structured interviews and secondary data from various sources. The data were analysed using descriptive and inferential statistics. The results show that 55.4% of the plastic waste discarded was low density polyethylene that was discarded by the public who were responsible for 69.3% of the plastic waste found discarded. According to the results, 50.7% of plastic wastes were disposed of at the open dumpsite at Timbotaka, in Watamu sub-location. Location of the respondents was a significant factor that influenced the level of knowledge, attitude and perception with respect to plastic waste disposal (FH = 25.729, p = 0.002; FH = 16.289, p = 0.033; FH = 24.145, p = 0.009). It also influenced the plastic waste disposal methods used by respondents (FH = 50.708, p = 0.000). Other factors that influenced plastic waste disposal methods include occupation FH = 30.082, p = 0.038), waste collection and presence of recycling centres. The existing plastic waste management methods are re -use and small-scale re-cycling done by locals and Eco-world respectively. In conclusion, the proximity of waste disposal sites determines the plastic waste disposal methods used by the locals. Therefore, for environmentally-sound management of plastic waste, disposal sites should be easily accessible. Further awareness campaigns and public education need also to be done on plastic waste management to facilitate proper disposal methods.
Characterization of Egerton University wastewater stabilization ponds and assessment of substrate size efficiency in reduction of faecal pollutants in a constructed wetland mesocosm
(Egerton University, 2018-04) Lukhabi, Dorothy Khasisi
The aim of this study was to determine variations in concentration of Pathogen Indicator Organisms (PIOs) namely total coliforms Escherichia coli and heterotrophic bacteria; Biochemical Oxygen Demand (BOD) in Egerton University Wastewater Stabilisation Ponds (WSPs) and the effect of substrate sizes on wastewater treatment. Sampling at the WSPs was done on weekly basis for one month from mid-Nov to mid-Dec 2017 using standard procedures for examination of water and wastewater. A mesocosm study imitating a vertical sub surface flow constructed wetland was conducted to determine the most efficient substrate size in removal of these pollutant indicators. Total coliforms (TC) and E. coli were isolated using selective and differential media following membrane filtration method Colonies were enumerated on chromocult agar. Heterotrophic bacteria (HPCs) were enumerated using standard pour plate method on plate count agar. Biochemical Oxygen Demand was determined by incubating samples in a cabinet whose room temperature ranged between 20 °C to 25 °C for 5 days. For the mesocosm study, three sets of experiments with different gravel aggregate sizes were set up in triplicates. Wastewater from SMP was introduced and settled for six weeks to enable micro-organisms to establish and stabilize, before collection of water samples for analysis on weekly basis for eight weeks. The highest concentration of both PIOs and BOD was in the inlet, and this reduced along the pathway towards the outlet. Apart from BOD5, there was a significant difference between the influent and effluent in all the parameters (p<0.05). The range for TC, E. coli, HPCs and BOD5 was 5.5 x 106 - 2.9 x 1011, 4.4 x 104 - 1.9 x 1010CFUs / 100 ml, 4.5 x 106 - 5.0 x 109 CFUs / ml and 142.8 - 163.6 mg/l respectively. Removal efficiencies ranged between 99.8-99.9 % (3 log units) for both TC and E. coli in both First Maturation Pond and Second Maturation Pond. Heterotrophic Plate Counts reduced in concentration along the treatment pathway by 2 log units. In the mesocosm study, percentage reduction efficiency for TC for different substrate sizes was recorded as 95.3, 90.4 and 88.8 % for small, medium and large gravel aggregate respectively, while E. coli was recorded as 95.2, 94.3 and 88.4 % and HPCs was 99.8, 99.7 and 99.5 %. Furthermore, removal of organic matter was recorded as 15.9, 9.9 and 8.4 % for BOD5 while TSS was 72.7, 56.6 and 52.4 % for small, medium and large sized gravel aggregates respectively. In conclusion, WSPs at Egerton University performed well in removal of PIOs. Heterotrophic bacteria levels indicated presence of pollution with easily degradable organic matter, while BOD5 levels did not. In addition, none of the substrate sizes employed in mesocosm study performed better than the other in removal of PIOs and organic matter
Longitudinal and seasonal variations in physicochemical and microbiological properties of water quality of Sosiani River, Uasin Gishu County, Kenya
(IISTE, 2019-04) Masakha, Edward Juma
Water pollution is the change in physico-chemical and biological properties of water quality that is harmful to living things. It is caused by pollutants drawn from point and non-point sources of pollution including industrial and agricultural effluents. It can also be attributed to inappropriate use of chemicals and haphazard disposal of waste. It has become a global concern due to the lethal and sublethal effects on fauna and flora. Sosiani River traverses Eldoret town, draining effluent openly discharged. This river is an important source of industrial and domestic water for residents living in Eldoret, Turbo and along the riparian. This study assessed longitudinal and seasonal variations in physicochemical and microbiological water quality. Composite water samples were collected from 13 effluent discharge points along Sosiani River for one year and analyzed using American Public Health Association water sampling and processing procedures. Medical data was collected from health facilities in Eldoret Township. Data was managed using Statistical Packages for Social Sciences version 20. Both descriptive and inferential statistics like analysis of variance, correlation and regression analysis were used in analysing the resultant data. Sosiani River exhibited high mean levels of turbidity at 64 ± 53.4 Nephelometric Turbidity Units, high biological oxygen demand at 122.8 ± 123.8mg/L, high chemical oxygen demand at 205.0 ± 190.2 mg/L, high total suspended solids at 173 ± 34.14 mg/L, high total dissolved solids at 171.3 ± 11.66mg/L, Escherichia coli at 57.0 ± 54.3mg/L Colony Forming Units /100ml, total coliforms at 135.1 ± 119.6CFU/100ml and cadmium at 0.048 ± 0.07mg/L above National Environment Management Authority (NEMA) guidelines. Sosiani River exhibited significant differences in seasonal and longitudinal variations in physico-chemical and microbiological properties of water quality at P<0.005. The river exhibited significant seasonal and longitudinal variation in levels of Escherichia coli at F = 5.10 and P < 0.001. However, prevalent water borne diseases in the study area; diarrhea at t = 0.6387, P < 0.5374; dysentery at t = 1.2839 P < 0.2281 and typhoid at t = 0.3588, P < 0.7272 did not vary significantly during the dry and wet season. Water Resource Authority and NEMA should ensure all industries and hotels use constructed wetlands or are connected to the centralised sewerage system. The County Government should relocate Huruma dumpsite from the banks of the river and plant trees and grass along the river. Residents should treat drinking water sourced from Sosiani River at household level. Finally access to adequate sanitation should be increased to curb haphazard disposal of solid and liquid waste.
Nitrogen loading and ground water contamination comparison among different farm sizes in Ainabkoi Sub-County, Uasin Gishu County,Kenya
(Egerton University, 2018-11) Kitonga, Lydiah Lucy Mbula
The mobility of nitrate-N (NO3-N), nitrite-N (NO2-N) and ammonium-N (NH4-N) down the soil profile and its ultimate presence in groundwater is aggravated by predisposing conditions such as farm agricultural activities and nitrogen fertilizer management, rainfall, seasons and well sanitary conditions. The main objective of the study was to assess the groundwater nitrogen loading compared in different farm sizes. The study was conducted in three agro-ecological wards of Ainabkoi sub-county. Each ward was identified as a homogenous stratum of same size-ranged farms. Farms in Ainabkoi ward were large, family-generations-owned mixed farm sizes and ranged 40-71 acres (16-29 ha) with an average farm acreage of 56 acres (23 ha). In Kaptagat ward farms were medium sized mixed farms on purchased settlement farms and ranged from 10-35 acres (4-14 ha). The small mixed farm sizes were located in Olare ward and ranged 2-10 acres (0.8-4 ha) in size. Farms in each ward were purposively selected such that only accessible farms that had access to either a privately owned or communal wells were selected. The study was carried out between 2012 and 2013. Onsite sanitary survey of the wells and the homesteads was carried out in each farm. A questionnaire was used to obtain general information on farm production and management, farm sizes, crops grown, crop acreage, cropping calendars, types and number of livestock animals kept, type and amount of fertilizer applied and well characteristics. The nitrate-N, nitrite-N and ammonium-N concentrations did not exceed the recommended maximum concentration by Kenya and WHO of 10mg/l, 3mg/l and 0.5mg/l respectively. The physico-chemical parameters were within the acceptable limits set by WHO except for turbidity. There was a positive linear relationship between the average fertilizer N amount at top dressing and the groundwater nitrate (Y = 0.0836x – 165.18 R2 = 0.31), hence N pollution is closely related to the amount and timing of fertilizer application. There were highly significant differences between precipitation and the N concentration although the trends were not clearly recognizable. There was a highly significant positive linear relationship between the monthly rainfall amount and NO3-N concentration in well water (Y = 0.1759x + 22.07 R2 = 0.23***). There were highly significant differences between the farm sizes in the sanitary contamination risk scores mainly due to individual farm endowments, well site environmental factors and ownership. Conclusively, precipitation, season and timing of fertilizer application were common significant predictors of the concentration levels of N in well water. The absence of any significant N contamination of groundwater in this study does not preclude it occurring in the future. Best nitrogen fertilizer management strategies should be adopted in order to synchronize N supply with crop seasonal demand such as timing and splitting of fertilizer N application and real-time monitoring of nitrogen in soil, plants and groundwater. Well conformity requirements with regard to the parameters of well construction and its vicinities are necessary.

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