Effect Of A Dump-Site On Soil Resistivity Using Terrameter

ABSTRACT

Electrical resistivity of soils is dependent upon various factors, including soil type, water content, saturation and pore fluid property. Experimental works have been performed to investigate the electrical resistivity of soil landfill leachate contamination. For three different tested soils, the electrical resistivity of soil exponentially decreased as moisture density increased. The adding of leachate having various ions decreased the electrical resistivity. Also, the formation factor can be described by the term of moisture density in unsaturated sand. The formation factor was higher when soil and pore water were contaminated by higher concentration of leachate than when soil is uncontaminated, since ionic movement is restrained by electro-chemical interactions between soil particles and leachate constituents.

 CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE STUDY

Waste is defined as unwanted or undesired materials accumulating after the completion of a process (Cointreau, 2011). Waste is also characterized as items that are no longer used for any significant function. They are classified as items with hazardous properties. Such hazardous wastes include household dump items, sewage, sludge, waste from manufacturing industries etc. (Obeka, 2015).

The municipal solid waste dumpsite (MSWD) examined is Lapite Dump Site, Moniya Oyo Road Akinyele LGA, Ibadan Oyo State. The dumpsites examined contain both biodegradable and non-biodegradable materials of all sorts. The different waste materials may contain different physical, chemical and biochemical properties. In the presence of atmospheric water, high temperature and high microbial populations, these waste materials may decompose and get dissolved in the presence of water to generate a waste liquid substance called leachate. This waste water produced may infiltrate into the ground water aquifer, it may be washed into a nearby surface stream and it may affect soil properties. When humans come into direct contact with such contaminated samples, it may lead to public health problems.

The gradual increasing population and the proliferation of basic industrial processes particularly in major cities of the world has led to civilization that have greater impact on the environment. The disposal of domestic, commercial and industrial garbage in the world is a problem that continues to grow with human civilisation and no method so far is completely safe. Experience has shown that all forms of waste disposal have negative consequences on the environment, public health, and local economies.

Dumpsites are often established in disused quarries, mining or excavated pits away from residential areas. Designated government agency, corporate bodies and some individuals collect wastes routinely into these dumpsites. Here in Nigeria and particularly in ibadan, modern landfill facilities are not found in these dumpsites; consequently sorting-out of wastes into degradable, non-degradable and recyclable precious materials cannot be achieved. Poor management of dumpsites could create a number of adverse environmental impacts, including wind-blow litter, attraction of mice and pollutants such as leachate, which can pollute underground soil bed, and / or aquifer. Landfill gas mostly composed of methane and carbon dioxide are produced through biodegradation of such waste. Leachate from dumpsites is of particular interest when it contains potentially toxic heavy metals.

Household and industrial garbage may contain toxic materials such as lead, cadmium, mercury, manganese from batteries, insect sprays, nail, polish, cleaners, plastics polyethylene or PVC (polyvinyl chloride) made bottles and other assorted products. Inorganic chemical contamination of the environment is due essentially to anthropogenic source, improper disposal and lack of awareness of the health-risk created by such indiscriminate disposal. Lead, cadmium manganese, arsenic and mercury are pollutants which have unknown physiological benefit when ingested (Abdus-Salam &Adekola, 2015; Brady & Weil, 2019).

 The evaluation of groundwater and soil properties has become increasingly important for site characterization when more industrial wastes and domestic solid refuse come into contact with groundwater and soils and cause subsurface contamination. One of the emerging techniques to assess the contaminated media is the electrical resistivity method, which can be performed rapidly and nondestructively in situ. Every soil possesses a natural resistivity within certain limits; deviations may suggest possible pollutions as the contaminants may influence the bulk resistivity of soil (Abu-Hassanein and others 2016). Alternatively, a terrameter can be employed at a relatively low cost for delineation of subsurface contamination in situ, and then be supplemented with a minimum confirmatory sampling and laboratory testing program. The use of the terrameter is particularly appealing because the meter can measure resistivity to a higher resolution and at the same time note change in lithology (Campanella and Weemees 2010). At first, the measurement of electrical resistivity (or conductivity) was developed to evaluate in situ density or porosity of sands.

As the factors affecting electrical resistivity of soils are very important for the characterization of contaminated subsurface, parametric studies based on laboratory tests have been performed in this paper. The objectives of this paper are twofold: first, to examine the relationship between electrical resistivity and the unsaturated subsur- face condition; and second, to investigate the variation of electrical resistivity and formation factor of unsaturated soils due to landfill leachate based on the laboratory-scaled experiments using terrameter.

1.2         PROBLEM STATEMENT

Inadequate solid waste management is a major environmental problem in Nigeria in general. The contributing factors range from technical problems, to financial and institutional constraints. There is an absence of any properly designed solid waste disposal facility in Lapite Dump Site, Moniya Oyo Road Akinyele LGA, Ibadan. Therefore posing contamination risk to the soil. The pollutant species in the dumpsites will continue to migrate and attenuate through the soil strata and after ascertain period of time if there is no action taken to prevent the phenomenon.

Soil contamination hinders plant growth by affecting the soil-water balance. Indiscriminate refuse dump affects soil quality which people seem not to be aware of and public education programmes that sensitize the public on the health implications of indiscriminate refuse dump are almost non-existent. Mass media seem not to be doing enough to create awareness about implications of indiscriminate refuse dump.

This research will appraise the public health awareness of the implications of indiscriminate refuse dump in the studied area.

1.3       AIM AND OBJECTIVES OF THE STUDY

The aim of this study is to assess the effect of leachate from solid waste dumpsites on the resistivity of soil in Lapite Dump Site, Moniya Oyo Road Akinyele LGA, Ibadan, Oyo State..

The objectives of the project are:

1. To identify the relationship between soil resistivity and distance from a dump-site
2. To assess the levels of soil resistivity in that area

iii.        To study the impact of dumpsite on soil.

1.4       SCOPE OF THE STUDY

The research work is mainly on soil quality in the areas selected in Lapite Dump Site, Moniya Oyo Road Akinyele LGA, Ibadan, Oyo State

The study examines the nature and characteristics of solid wastes in the area and the effects of the dumpsite on soil close to the dumpsite.

Threedifferentlocalsoils–sandysoil,weatheredgranitesoil,andsiltysand–commonlydistributedaroundtheLapite Dump Site wereusedtoinvestigatetherelationshipbetweenelectricalresistivityandunsaturatedsoilproper-ties.

1.5       SIGNIFICANCE OF THE STUDY

This research will help to highlight the relationship between the physical state of an environment and the resultant health implications of mismanaging it. This will help physical planners and farmers to coordinate their activities in relation to soil quality.

This study will help electrical engineers to determine the right place to design the grounding system in an electrical substation, or for lightning conductors. It is needed for design of grounding (earthing) electrodes for substations and High-voltage direct current transmission systems.

In addition, it is also hoped that the research outcome will contribute to the existing body of knowledge on the subject matter.

1.6       DEFINITION OF TERMS

Soil resistivity:  is a measure of how much the soil resists or conducts electric current.

Leachate: is any liquid that, in the course of passing through matter, extracts soluble or suspended solids, or any other component of the material through which it has passed.

Dumpsite: a piece of land where waste materials are dumped. garbage dump, rubbish dump, trash dump, wasteyard, waste-yard, dump. eitchen midden, kitchen midden, midden – (archeology) a mound of domestic refuse containing shells and animal bones marking the site of a prehistoric settlement.

1.7      LOCATION OF THE STUDY

Research work was carried out on Lapite dumpsite, which is situated in Akinyele Local Government of Ibadan, Oyo State. The study area lies between latitude 7 °34′ 08″ N and longitude 3° 54′ 43″ E. The well water which is in the region of the dumpsite is sited at latitude 7 °33′ 48″ N and longitude 3° 54′ 45″ E as shown in Fig. 1. The dumpsite is directly opposite a major road and there are vegetations at both sides of the road. There are few residential buildings, a re-habitation center, a petrol filling station and a few huts around the dumpsite. Some of the solid waste found on the site includes: scrap metals materials, garbage, paper, nylon, rubber, ETC.