System Dynamics Modeling of Dumpsite Leachate Control in Ogbomosoland, Nigeria

Leachate pollution from landfills is a major source of environmental hazard in many Nigerian municipalities and there is the need to mitigate its effects. The aim of this study is to examine the leachate pollution and determine the effectiveness of liner system in leachate management of dumpsites in Ogbomosoland. The method of modeling us ing principles of system dynamics was employed to determine the interrelationships of leachate generation components for 50 years. Causal loops indicating the linkage of population, economic status, waste generation per capita and weather conditions to wastes and leachate generation were developed. A set of state model equations for Gas Produced (Gp), Precipitation (Pt), Degradation water-loss (Wg), Leachate Quantity (LQn), were formulated. Leachate management strategies of liner systems were studied, and the effectiveness of Compacted Clay (CC), High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE), Geosynthetic Clay (GC), Silt (SI), Sandy loam (SL), and Sand (SA) liners were examined. A user-friendly computer program for estimating leachate generation per time and breakthrough time for liners was then developed. The results showed that a direct relationship exists between leachate and Gp, Pt, Wg and LQn. Average leachate breakthrough times for the liners, in years, were CC (41.5), HDPE (14.0), LDPE (10.0), GC (1.1), SI (0.1), SL (0.01), and SA (0.00002). In conclusion, dumpsite leachate pollution was established as having negative effects on the groundwater resource. Compacted Clay liner is therefore recommended for use in curtailing its menace.

Contamination Levels of Some Selected Wells in Ogbomoso South Local Government Area, Nigeria and the Implications on Human Health

Incident of water-borne diseases is becoming more rampant in developing countries in the 21st century. This paper examines the contamination levels of some selected wells in Ogbomoso South Local Government Area (LGA), Oyo State, Nigeria. Methodology includes administering of structured questionnaire, field survey/sampling and laboratory analysis. The first set of questionnaires sought information on water sources, quality, supply and treatment. These were administered in 10 selected major locations which included: Ajegunle, Arinkinkin, Arowomole, Caretaker, Esanu-Aje, Ita-Olola, Malete, Oke-Alapata, Ora-Gada and Sunsun. The other set which was administered in 6 randomly selected Health Institutions viz: Oyo State General Hospital, Alaafia Tayo, Oore-Ofe, Bethel, Favour, and Grace Hospitals had questions on health-related issues. Ten (10) wells were randomly selected for sampling, one in each location. Results were compared with WHO’s Drinking Water Standards. Questionnaires revealed that residents depended mostly on wells for water supply;the water quality was low;supply was irregular;quantity was inadequate and boiling was the commonest treatment method. Health Officials established that some residents consumed improperly treated well water and there were some incidences of water-related diseases. Laboratory analyses showed that samples from Ajegumle and Esanu-Aje had colour values above the standard. Also, the pH was observed to vary from slightly acidic to slightly alkaline with values ranging between 6.0 and 8.1. Only Arinkinkin and Ita-Olola areas had permissible values of total alkalinity and Oke-Alapata had the highest chloride value of 400 mg/l while the highest nitrate concentration was at Esanu-Aje (127.58 mg/l). Study concludes that water supply in the area is not fully supportive to health. To abate the problem, it is recommended that aside boiling, each household should endeavour to coagulate, filter, soften and disinfect well water before consumption. Also, personal hygiene within each household must always be emphasized and improved upon.

Application of TRACI and CML Modeling Tools in Life Cycle Impact Assessment of Municipal Wastes

In this study, the Tool for the Reduction and Assessment of Chemical and other Environmental Impacts (TRACI) of the United States Environmental Protection Agency and the methodology of the Centre for Environmental Studies (CML) of the University of Leiden are two approaches applied as provided for in the GaBi5 (Holistic Balancing) Life Cycle Assessment (LCA) software database, to classify and characterize environmental impacts of municipal wastes in Ogbomoso South Local Government Area (LGA), Nigeria. On waste composition, 5 representative households were selected, each from the cardinal polling units in Ibapon (ward 4) for the study. Wastes samples were collected from the households over a period of 5 days, sorted, classified according to their constituents and weighed accordingly. For the Life Cycle Impact Assessment (LCIA), two waste management scenarios/models were developed and compared using GaBi5 software. Scenario 1 involves collection, transportation and landfilling, while Scenario 2 ends with incineration. The Impact Indices determined from both scenarios were: Global Warming Potential (GWP), Acidification Potential (AP), Eutrophication Potential (EP) and Ozone Layer Depletion Potential (ODP). Findings show that the overall mean percent (%) wastes composition for biodegradable, metal, textile, paper, plastic, glass and wood were respectively found to be 55.9, 9.5, 2.4, 6.5, 6.7, 6.6, and 12.2. From the results of LCIA methods studied, landfilling of wastes poses a lesser burden on the environment, using the ODP index, as compared to incineration. It is concluded that of the management scenarios considered, landfilling of wastes is more environmentally friendly and therefore recommended for use in the study area.

C-Language Programming for Development of Conventional Water Treatment Plants Decision Support System

Water-Decision Support System (DSS) tools enhance decision-makings towards improved water supply in a given region. The rigours of manual design of the conventional water treatment plants are easily eliminated with the use of softwares as in the case of DSS. Therefore, this paper focuses on the development of a Water-DSS for design of treatment plant in Karkala Town, Udupi District of India. A four-decade population projection was made using the baseline data of 1971 till date. The manual computation for water demand, unit operations and adjoining facilities was carried out and later coded in C-programming language for development of a DSS for easier design and process selection. Data validation was done and results from the two approaches were compared. With the C-programming technique, a decision support tool for design and process selection of drinking water treatment plant using conventional method has been developed and named Water-DSS1. The designed tool is simple, accurate, flexible, efficient and universal, easily adaptable to any similar conventional treatment plant. Water-DSS1 is thus recommended for general use in ultimately alleviating water supply challenges.

Susceptibility of Some Selected Nitte Municipal Wastewater Sources to Trace Metals Pollution

The negative impacts of pollution due to trace metals in wastewater on aquatic ecosystem and related organisms in water bodies are on the increase. This paper deals with the investigation on the pollution indices of trace metals in selected wastewater samples of Nitte Town, Udupi District, Karnataka State, India. Twelve wastewater samples were obtained from Students Hostels, Auto-Service Workshop Station, Foundry, Laundry, Landfill Leachate and Wastewater Treatment Plant Inlet. The measured heavy metals in the samples include: Copper (Cu), Lead (Pb), Magnesium (Mg), Chromium (Cr), Nickel (Ni), Zinc (Zn), Manganese (Mn) and Cadmium (Cd), using the air-acetylene-operated Flame Atomic Absorption Spectrometer (FAAS), Avanta GM model. The results were all compared with the EPA Effluent Standards. Findings revealed that all samples recorded dwindling levels of trace metals pollution when compared with the Standards. The heaviest concentration occurred in Cd with as high as 1856.4 ppm as found in the Stale Landfill Leachate sample, while the least contaminating metal in the samples is Manganese which was detected in only Aerated Wastewater Treatment Plant sample (2.3 ppm). This study is therefore recommending Electro-coagulation treatment method for trace metals with high concentration levels like Cd, Pb, Mg and Cu, while those with lesser concentration such as Mn, Cr, Ni and Zn in the samples are suggested to be treated with chemical precipitation method.

Characterization of Dumpsite Leachate: Case Study of Ogbomosoland, South-Western Nigeria

Leachates contain varying complex characteristics. The 5 Local Government Areas (LGAs) under this study that characterized leachate are no exceptions. Five aged dumpsites, one per LGA were selected and leachates extracted from them through BS 1377 standard method. Samples were taken seasonally over 2 years and subjected to Laboratory analyses for physical, inorganic, metallic and microbial characteristics. The key leachate contents mean, (pollution indices) included Nickel (0.2 mg/l), Manganese (1.8 mg/l), Dissolved Oxygen (11.5 mg/l) and Total Coliform (24.3 cfu/ml). Results obtained were compared with the Nigerian Federal Environmental Protection Agency (FEPA) standards. The leachate of the area is found to be stable, objectionably coloured, odoured, alkaline, turbid, hard, with moderate recalcitrant organic and biological matters. The study recommends leachate treatment to minimize groundwater pollution.