EVALUATING THE EFFECTIVENESS OF SEWAGE TREATMENT PLANTS IN PREVENTING ENVIRONMENTAL POLLUTION IN YAOUNDÉ, CAMEROON

CHAPTER ONE

INTRODUCTION

Background of the Study

Globally, the rapid increase in urbanization, driven by the migration of people from rural and semi-urban areas to cities in quest of better opportunities, has led to severe sewerage problems in many large cities worldwide, particularly in developing nations. The 1995 assessment by the Central Pollution Control Board (CPCB) revealed that the sewer systems in the major Indian metro-cities of Delhi, Bombay, Calcutta, Madras, and Bangalore only serve 40-50% of their inhabitants. Even in areas where sewage systems are present, they are often inadequately designed, constructed, or maintained. According to a report, there are more than 5,200 water bodies in the United States that fail to meet the required water-quality criteria for their intended use due to the presence of pathogens. Additionally, approximately 4,800 water bodies are impaired due to the presence of nutrients, which can be attributed to the failure of onsite treatment and disposal systems (USEPA, 2020). 

Literarily, sewage disposal refers to the method of managing and eliminating wastewater from residential and commercial establishments. This wastewater, often consisting of a liquid containing minute solid particles, is transported through enormous pipes known as sewers. The objective is to generate waste that is safe for the environment (Ask, 2019). The wastewater is either routed to a specified location for recycling or disposed of in a remote area to prevent the spread of infections. Proper disposal of sewage waste safeguards public health and mitigates the risk of disease transmission, while also preventing water pollution caused by sewage toxins. Moreover, the discharge of sewage into natural bodies of water is a widespread practice in numerous countries. Significant amounts of organic matter and nutrients from untreated sewage entering a poorly flowing water system can lead to environmental and health issues due to the degradation of water quality (Ribeiro and Araujo, 2018; Rajagopalan, 2019)

According to Al-Dahmi, 2019) insufficient or defective sewage and/or sewage treatment systems or plants are significant contributors to pollution in natural bodies of water. According to Nikuze et al. (2018) sewage treatment plants are facilities designed to treat and process sewage) from residential, commercial, and industrial sources to remove contaminants before the water is released back into the environment. These plants typically employ a series of physical, chemical, and biological processes, such as sedimentation, filtration, aeration, and disinfection, to reduce the levels of organic matter, pathogens, nutrients, and other pollutants. The goal of sewage treatment plants is to protect public health, prevent environmental pollution, and ensure that the treated water meets regulatory standards for discharge or reuse.

Similalrly, Cimino in 2018 pointed that raw sewage comprises urine and faeces from toilet flushing, together with various forms of human waste. Additionally, it may contain items like toilet paper and wipes. These may also encompass tampons and other feminine hygiene supplies. The presence of microorganisms in untreated sewage has the potential to not only cause illness in humans and animals, but also to harm natural systems. Furthermore, raw sewage consists of various components such as oxygen-demanding organics that can reduce the amount of dissolved oxygen in water bodies, pathogenic microorganisms that can cause diseases (such as E. coli, hepatitis A, and cholera), and nutrients that can promote the growth of aquatic plants (Theodorou, 2018; Akoachere et al., 2019). Sewage may also contain substances that have the potential to be poisonous, mutagenic, or carcinogenic (Al-Muzaini et al., 2019). In addition to being exposed to germs and viruses, those who come into contact with raw sewage may have various ailments, such as gastroenteritis, characterised by symptoms such as diarrhoea, vomiting, and stomach pain. Weil's disease, which can occasionally be fatal, is a prevalent issue that manifests flu-like symptoms and can result in liver and kidney damage. In addition, sewage disposal sites located on the outskirts of urban areas become breeding grounds for flies, mosquitoes, and rodents. These pests are carriers of diseases that can negatively impact the health of the population, particularly when their immune systems are still developing. The aforementioned scenario gives rise to gastrointestinal, dermatological, pulmonary, genetic, and various other types of infectious disorders. Therefore, a survey will be conducted in order to evaluate the effectiveness of sewage treatment plants in preventing environmental pollution in Yaoundé, Cameroon.

Statement of the Problem

In recent times, the issues related to sewage disposal have emerged as a significant challenge in metropolitan areas as a result of the rise in human population and urbanisation. The prevalence of sewage-related issues in coastal regions worldwide is substantial, given that these areas are home to more than 60% of the global human population. Domestic wastewater discharges are widely recognised as a major danger to coastal habitats globally (GPA, 2021). The environmental impacts linked to the discharge of domestic wastewater are often confined to local areas, however they may have transboundary consequences in certain regions.  

Considering the properties of untreated wastewater and the criteria for its disposal or reuse, it is typically necessary to subject the wastewater to some form of preparation or treatment in order to make it suitable for disposal or reuse. Typically, the treatment of domestic wastewater primarily focusses on eliminating total suspended particles and 20°C BOD5, which are the two most significant parameters of concern. The level of treatment given to the wastewater is mostly determined by the effluent standards set by regulatory agencies for when the treated wastewater is released into a river or land. The quality of the effluent needed for reuse will determine the level of treatment required. The wastewater treatment process involves a sequential mix of several physical unit activities and chemical and biological unit processes. The primary criterion for assessing the effectiveness of a sewage treatment plant is the extent to which it reduces the levels of biochemical oxygen demand (BOD) and suspended solids, which are the main components of organic pollution (Garbowski, Wiśniewski, & Bawiec, 2019). The effectiveness of the treatment plant relies not only on appropriate design and construction, but also on proficient maintenance and operation (Kumar et al., 2019). 

Multiple studies have emphasised the difficulties encountered by STPs (Sewage Treatment Plants) in Yaoundé. These factors encompass technical inefficiencies, insufficient maintenance, and a dearth of financial resources to sustain the functioning of these facilities. Ngnikam and Tanawa (2018) highlighted that numerous sewage treatment plants (STPs) in the city are either non-operational or functioning below their intended capacity. Consequently, this results in the release of improperly treated sewage into the environment. The environmental consequences of this are severe, as untreated sewage is a major contributor of pollutants, such as pathogens, nutrients, and dangerous compounds, which lead to the deterioration of water quality in rivers, streams, and other bodies of water (Ngnikam & Tanawa, 2018). Hence, it is in the light of these that the study seeks to evaluate the effectiveness of sewage treatment plants in preventing environmental pollution in Yaoundé, Cameroon.

 1.3  Objectives of the Study

The main purpose of this study is to evaluate the effectiveness of sewage treatment plants in preventing environmental pollution in Yaoundé, Cameroon.  Specifically, the study will;

Assess the level of operational efficiency of sewage treatment plants in Yaoundé.

Evaluate the effectiveness of sewage treatment processes in reducing pollutants and contaminants in Yaoundé.

Assess the challenges faced by sewage treatment plants in maintaining high standards of environmental protection.

1.4  Research Questions

The following questions have been prepared for the study:

What is the level of operational efficiency of sewage treatment plants in Yaoundé?

How effective are the sewage treatment processes in reducing pollutants and contaminants in Yaoundé?

What challenges do sewage treatment plants in Yaoundé face in maintaining high standards of environmental protection?

1.5 Research Hypotheses

H0: Sewage treatment plants in Yaoundé are not effective in preventing environmental pollution.

Ha: Sewage treatment plants in Yaoundé are effective in preventing environmental pollution.

1.6 Significance of the Study

The findings will inform decisions on infrastructure investments, operational improvements, and regulatory measures needed to enhance the effectiveness of sewage treatment in preventing environmental pollution in Cameroon. Additionally, the study will contribute to a cleaner, healthier environment in Yaoundé, reducing the impact of sewage on the city's natural resources and public health.Moreover, subsequent researchers will use it as a literature review. This means that other students who may decide to conduct studies in this area will have the opportunity to use this study as available literature that can be subjected to critical review.

1.7 Scope of the study   

The scope of this study is boarded on the effectiveness of sewage treatment plants in preventing environmental pollution in Yaoundé, Cameroon. Empirically, the study will assess the level of operational efficiency of sewage treatment plants, evaluate the effectiveness of sewage treatment processes in reducing pollutants and contaminants and assess the challenges faced by sewage treatment plants in maintaining high standards of environmental protection.

Geographically, the study will be delimited to residents of Yaoundé, Cameroon.

1.8 Limitation of the study

In the course of carrying out this study, the researcher experienced some constraints, which included time constraints, financial constraints, language barriers, and the attitude of the respondents. In addition, there was the element of researcher bias. Here, the researcher possessed some biases that may have been reflected in the way the data was collected, the type of people interviewed or sampled, and how the data gathered was interpreted thereafter. The potential for all this to influence the findings and conclusions could not be downplayed. More so, the findings of this study are limited to the sample population in the study area, hence they may not be suitable for use in comparison to other schools, local governments, states, and other countries in the world.

 1.9 Definition of Terms

Sewage: Wastewater that is generated from domestic, industrial, and commercial activities, which typically contains human waste (feces and urine), household waste (such as detergents and food residues), and water used for washing, bathing, and cleaning.

Sewage disposal: The process of collecting, treating, and safely discharging or recycling sewage to prevent pollution and protect public health.

Environmental Pollution: The introduction of harmful substances or pollutants into the natural environment, air, water, and soil that cause adverse effects on ecosystems, human health, and the overall quality of life.

Sewage Treatment Plants: Facilities designed to treat and process wastewater (sewage) from residential, commercial, and industrial sources to remove contaminants before the water is released back into the environment. 

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