POLLUTION PROBLEMS AND AN ENGINEERING APPROACH TO THE MANAGEMENT AND CONTROL OF INDUSTRIAL EFFLUENTS

POLLUTION PROBLEMS AND AN ENGINEERING APPROACH TO THE MANAGEMENT AND CONTROL OF INDUSTRIAL EFFLUENTS

ABSTRACT

The impacts of effluent discharges from various point-loads on a purposefully selected receiving river, the river’s self-recovery potential, and the treatability of both the discharges and the receiving stream in a heavily industrialized community were investigated in this study.

The work entailed conducting a field survey of industries producing and discharging effluents in the study area (Ado Odo/ Otta industrial zone of Ogun State, Nigeria); determining the physico-chemical, biological, and microbial characteristics of the effluents, and determining the impact of the discharged effluents on the receiving surface water using standard methods. Primary data were also gathered for analysis through the use of structured questionnaires and oral interviews to elicit the impact of industry to water pollution.

Various scenarios for enhancing water quality along the river under consideration were investigated to enhance the analytical process. A variety of computer-based hydrogeometric and water quality models were studied. QUAL2K was used for hydrogeometric and water quality study of the Atuwara River as a one-dimensional steady state and totally mixed system. The 10.81 km long length from upstream at Owode – Ijako to Iju Water Works was mapped using GPS and divided into 7 spans with additional segmentation of 0.3 km each, from which grab samples were routinely taken during the study period.

Using established procedures, the researchers examined the wastewater discharges from all industries along the river for priority pollutants such as BOD, COD, TDS, TSS, and heavy metals. During the dry and wet seasons, effluent samples were collected and compared to river water samples before and after receiving waste loads. The model output was interfaced with geographical information systems (GIS) to demarcate polluted zones, limnographic spots, and wetlands in the Atuwara watershed. The worst case scenario of effluent samples was obtained for laboratory-scale treatability experiments by using electro – Fenton alone or in combination with additional treatment with Granulated Activated Carbon (GAC) type BBC 945 to properly remove residues of heavy metals.

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The results revealed that the effluents were acidic in both seasons, with a pH range of 5.4 to 6.7. BOD and COD concentrations were also extremely high, particularly immediately downstream of discharge locations. The dissolved oxygen (DO) level at discharge points remains anoxic, with the DO steadily increasing downstream to each discharge point but significantly higher where tributaries discharge into the river under study. Because of the contribution from the tributaries, the river has a very high assimilative capacity. The worst-case scenario for BOD emission was estimated to be around 12 metric tonnes per day. Heavy metals (cadmium, lead, and iron) levels were somewhat higher than the FEPA standard in all portions of the river. All of this suggested that the river was harmed and should be labeled contaminated and unsafe for human consumption in the absence of suitable treatment.

According to the findings of the study, the Atuwara River is severely contaminated. Treatment of the worst-case scenario effluent collected from an industry revealed that COD removal of more than 66% was achieved with electro-Fenton treatment at a molar ratio of H2O2/Fe2+ between 150-250, using 0.3M H2O2 and 0.002M Fe2+, and COD removal of 86% was achieved when further treated with the GAC 945 sample.

To achieve the river water quality specified by regulatory authorities, it is recommended that the government enforce substantial load curtailment from the firms discharging the effluents through mandatory provision of in-house adequate treatment and at regulated flow rate to meet the National standards.

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CHAPITRE ONE

1. FORMAL INTRODUCTION

1.1 The Study’s Background

Water is life, and the quality and sufficiency of water are critical indicators of the quality of life, or rather the existence of life. As a result, water quality management is (or should be) one of humanity’s most vital activities in order to safeguard and save human life. Water quality management, or the protection of the aquatic ecosystem in general, entails pollution control. Water contamination is caused by anthropogenic activity and comes from both point and non-point (diffuse) sources.

The quantitative determination and description of the relationship between human activities and the state of the aquatic system is a critical feature in the series of complicated operations of planning and implementing water pollution management actions. These tasks are required for aquatic system modeling (hydrological, hydrodynamic, hydraulic, and water quality modeling) (Jolankai, 1997).

Planning and management operations include an assessment of hydraulic and water quality conditions that are frequently outside the scope of available field data. In this context, hydraulic and water quality models that are general enough to (1) characterize actual conditions and (2) forecast planned scenarios that may change significantly from observed conditions are required. The primary goal of stream water pollution control is to determine if the system meets the maximum pollutant release allowed from point and non-point sources of pollution, such that pollutant levels in receiving streams meet water quality criteria. Water quality models for in-stream water pollution mitigation have been calibrated and validated using data acquired prior to model creation during basin-wide water quality assessments for regulatory compliance (Radwan et al, 2003).

1.2 Problem Identification

During the planning, development, building, and final occupation stages of engineering projects, significant environmental deterioration occurs.

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Deforestation, land and water pollution, and ground water contamination are among the issues. Other issues include poor environmental sanitation, a badly planned road network, air and noise pollution, the disruption of the natural food chain, toxicity and radioactivity within the eco-system, and so on. Others include:

– Rapidly expanding industrial wastewater generation and release into available water courses

– Growing challenge for enterprises in complying with and meeting regional and national water quality requirements and limits

– The occurrence of water-borne diseases is increasing as a result of pollution from indiscriminate industrial effluent discharge into water channels.

– Deterioration of water quality requirements, as well as the consequences for water supply, aquatic ecosystems, and public health as a result of river pollution in inhabited regions

– Service delivery standards: Many existing national environmental standards and environmental management practices are based on those produced in industrialized countries under completely different conditions than those found in developing countries.

These standards are frequently incorrect, and even when they are in theory appropriate, they are frequently not implemented due to excessive costs.

1.3 Research Objectives

The following are the research objectives:

i. Determination of the diluting power and self-recovery ability of a specifically chosen river in the Ado-Odo/Otta District after receiving industrial effluents, and

ii. Evaluation of the industrial waste management capability of chosen industries’ treatment facilities.

1.4 The Study’s Specific Objectives

The exact goals of this research are as follows:

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1. Characterize chosen industrial effluents and assess their impacts on a set of receiving water courses.

2. Determine the ability of the specified receiving stream to recover from the environmental impacts of industrial activity using an existing model, and

3. Determine the effluents’ treatability and offer an engineering solution to the consequences.

1.5 Justification for the Study

There has been no systematic scientific and engineering assessment of industrial influence on rivers in Ado-Odo/Otta Industrial Zones, according to existing literature. There is currently a global emphasis on sustainable consumption and manufacturing activities by industries. As a result, enterprises must ensure compliance with the Federal Environmental Protection Agency (FEPA) of Nigeria as well as other national and international legislation.

Engineers will benefit from the findings of this study in the design and management of industrial waste.

1.6 Scope of the Research

i. The scope of this study was restricted to a field survey of selected industries that discharge industrial effluents into the Atuwara River.

ii. Laboratory scale modeling of pollution consequences utilizing the United States Environmental Protection Agency’s (USEPA) QUAL2K software to evaluate the hydrodynamics and water quality of the receiving river; and

iii. Laboratory bench – scale treatability investigation and analysis of identified contaminants of concern in selected businesses’ effluents

1.7 Limitations of the Study

The research focused on the River Atuwara in the Otta Municipal Districts. The primary polluting industries in Otta’s industrial layouts will be identified in three key industrial areas: Idiroko road, Ijoko road, and the Lagos-Abeokuta expressway. A prototype

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The receiving streams’ one-dimensional hydrodynamic and water quality metrics will be investigated.

1.8 Operational Terminology Definition

Industrial pollution is a broad category of pollution caused by manufacturing processes. Air pollution, water pollution, and solid and hazardous wastes are all examples of industrial pollution.

Industrial wastes: Potentially hazardous substances found in industrial and radioactive waste from chemical plants and nuclear power plants include petro-chloro-benzene (PCBs), tributylin (TBT), organo-chlorides, heavy metals (HMs), acidic wastes, radioactive caesium, and plutonium 239 (Falconer, 1990).

Industrial effluent is wastewater discharged from industries that has been partially or completely treated. It is typically unacceptable to discharge untreated industrial wastewater directly into rivers, land, or mine shafts, wells, and so on. Industrial wastewater also includes gaseous discharges from stacks.

Industrial wastewater management is the practice of minimizing wastewater production for recovery and reuse. The economical recovery and reuse of wastewater allows the cost of wastewater treatment to be reduced. The industrialist has three options: (1) treat or partially treat at the source on-site; (2) treat at a centralized works effluents plant on-site; or (3) release the wastewater to a sewer and pay for off-site treatment.

Water quality is a phrase used to describe the chemical, physical, and biological properties of water, usually in relation to its suitability for a specific use.

Mathematical models: Mathematical models are useful tools for assessing computer systems. Without the use of mathematical models, it is impossible to assess the various components and their interactions in an ecological system.

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Synthesis software. Dynamic system features can be revealed via mathematical models. They highlighted knowledge gaps in ecological systems and may thus be used to establish research objectives as an idealized formulation that represents a physical system’s reaction to external inputs.