PROGRESSIVE HEAVY METAL CONCENTRATIONS IN INDUSTRIAL EFFLUENTS

Abstract: This research was carried out to determine the progressive heavy metal concentrations in industrial effluents, serving as an indicator of the pollution potential of the industry. Effluent samples were analyzed for concentrations of lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg), zinc (Zn) and nickel (Ni) using standard methods of analysis. The study was carried out for a two year period in order to observe the nature of discharged effluents and their impact on the surrounding environment. The heavy metal results obtained showed that effluents samples were appropriately decontaminated of heavy metals as concentrations of most metals were  <0.001mg/L for the period of the study. The results compared with WHO specified limits were found to be within acceptable limits. The effluent was considered fit to be discharged into the surrounding water bodies with little or no environmental or health risks.

TABLE OF CONTENTS

PAGES

Title Page                                                                                                         i

Certification                                                                                                    ii

Dedication                                                                                                       iii

Acknowledgement                                                                                           iv

Table of Contents                                                                                            v

Abstract                                                                                                           vi

CHAPTER I: INTRODUCTION & LITERATURE REVIEW

Background of the Study                                                                                    1

Statement of the Problem                                                                                   2

Aim and Objectives of the Study                                                                        3

Significance of the Study                                                                                    4

Scope of the Study                                                                                              4

Area of the Study                                                                                                4

Literature Review                                                                                               6

CHAPTER II: MATERIALS AND METHODS

Materials                                                                                                            34

Sample Collection                                                                                             34

Methods                                                                                                             34

CHAPTER III: RESULTS

Results                                                                                                               36

CHAPTER IV: DISCUSSION, CONCLUSION AND RECOMMENDATION

Discussion                                                                                                        37

Conclusion                                                                                                       41

Recommendation                                                                                             41

Reference                                                                                                        43

Appendix                                                                                                         48

CHAPTER ONE

1.0  INTRODUCTION

1.1    BACKGROUND OF STUDY

Contamination of the environment from a variety of sources has become an increasingly serious problem in recent years. This problem might not be unconnected with the rapid industrialization, population growth and technological advancement being experienced in most parts of the world today. Heavy metal(s) are widespread pollutants of great concern as they are non-degradable and thus persistent. These metals are used in various industries from which effluents are consequently discharged into the environment. Accumulation of these metals has been reported mainly due to non-treatment or poor treatment of industrial effluents. When such metal bearing waste streams are insufficiently treated before discharge, they find their way into the environment and subsequently into the food chain. Heavy metals in air, soil, and water are global problems that are a growing threat to the environment especially in developing countries like Nigeria. The presence of heavy metals in aqueous streams and effluent has become a problem due to their harmful effects on organisms, including humans even at low concentrations. Common sources of heavy metal pollution include discharge from industries such as electroplating, plastics manufacturing, chemical and fertilizer producing plants and wastes left after mining and metallurgical processes (Zouboulis et al., 2004). The heavy metals: lead, cadmium, copper, zinc and nickel are among the most common pollutants found in industrial effluents (Djeribi and Hamdaoui, 2008) as they or their compounds have been used extensively by various metal-finishing, mining and chemical industries.

Effective treatment of heavy metal containing wastewater becomes a challenging task due to the fact that cost-effective treatment alternatives are not available. Wu and Zhou (2009) listed the main methods of heavy metal removal as ion exchange, chemical precipitation, electrolytic extraction, etc. yet most of them have disadvantages like high cost, large input of chemicals and incomplete removal. Therefore, proper treatment of industrial effluent is essential in order to safeguard public health, social security and accomplish environmental integrity.

1.2     STATEMENT OF THE PROBLEM

Discharge of effluents from industries is among the major environmental problems encountered in industrial locations. Heavy metals are introduced into the eco-system by the manufacturers and the use of materials containing heavy metals as well as the disposal of this waste.  The use of water as a coolant, in the purification of raw materials or their finished products in industries and its consequent discharge as wastewater is also a major process by which these metals get into ecosystem.  Aquatic ecosystem and humans risk exposure to heavy metals from untreated or poorly treated industrial effluents. This may result in bioaccumulation of these metals and consequently health risks over time. Effective and efficient methods of treatment of industrial effluents prior to its discharge would go a long way in curbing the numerous risks posed by heavy metal contamination.

1.3     AIMS AND OBJECTIVES OF STUDY

1.3.1  Major Objective

To determine the concentrations of selected heavy metals present in effluents of a typical chemical industrial plant in Port Harcourt area of Rivers State between 2015 and 2017 which would aid in determining the pollution potential of the plant.

1.3.2 Specific Objectives

The overall objective of this research is to compare and evaluate the content of heavy metals in industrial effluent with standard permissible values. And also to address the highly elevated levels of heavy metals found in wastewaters from industries.

The specific objectives of the study are to:

• Analyse the current situation of environmental pollution caused by toxic heavy metal contaminants.
• To determine the heavy metal condition of effluents from a chemical industry.
• Identify constraints to be overcome by industries in order to successfully discharge effluents thus eliminating health risks posed by them.
• To determine the pollution impact of the chemical industry in question by ascertaining compliance with specified WHO and other organizations standard limits.

1.4     SIGNIFICANCE OF THE STUDY

The findings of this study will redound to the benefit of the society if appropriate preventive measures are employed in the treatment of industrial effluents in order to rid them of toxic heavy metals and its subsequent discharge into water bodies are employed.

This is generally beneficial to the environment, serves as a way to curb the activities of chemical industries, minimize waste, and provide safe, clean and reusable water, save cost by complying with regulations and legislature among others in the study area.

1.5     THE SCOPE OF THE STUDY

The scope of the present study encompasses the analysis of heavy metals, namely cadmium (Cd), chromium (Cr), iron (Fe), lead (Pb), nickel (Ni), mercury (Hg), and zinc (Zn) in effluents from a chemical industry.

1.6     THE AREA OF STUDY

The study was carried out in a chemical plant located at Rumuodara, along East-West road, Port Harcourt, Rivers State. The chemical industry is involved in the production of products such as surfactants (cleaners), inhibitors, defoamers, emulsion breakers, process separation aids, etc., and commodity chemicals such as calcium chloride, xylene, dyes, sulphuric acid, etc.

Port Harcourt is the capital and largest city of Rivers State, Nigeria. It lies along the Bonny River and is located in the Niger Delta. As of 2016, the Port Harcourt urban area has an estimated population of 1,865,000 inhabitants, up from 1,382,592 as of 2006 (Demographia, 2016).

Port Harcourt has a tropical climate. Rainfall is significant most months of the year, and the short dry season has little effect. This climate is considered to be an Am according to the Kӧppen-Geiger climate classification. The average annual temperature is 26.4 ̊C. Precipitation here averages 2708mm.