ABSTRACT
Industrial wastewater treatment covers the mechanisms and process used to treat water that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-use.
Water is a natural and inorganic solvent with the composition of hydrogen and oxygen only (H20). When there is addition of other organic or inorganic, substances (high levels of nutrients, nitrogen and phosphorous) in water which may come as a result of weather change domestic, waste, industrial waste, lack of awareness and ignorance, then the water is known as waste water which cause a disease called water borne diseases.
Wastewater is very dangerous especially to human beings and should be treated to avoid these dangerous diseases.
There are many method of treating waste water and they include:
– Primary Method
– Secondary Method
– Tertiary Method
The primary method involves many treatment process such as;- screening process, skimming process and sedimentation process.
The secondary method of treatment also involves such treatment process such as aerated lagoons process, trickling filters process etc.
The tertiary method is the final method that involves disinfections process. This process is used to polish and bring back the quality of water which include: PH value, hardness, flories, taste suspended solid, colour etc (Uche, 2011).
CHAPTER ONE
1.0 INTRODUCTION
Water is essential for the survival of any form of life. On an average, a human being consumer about 2 litres of water everyday. Water accounts for about 70% of the weight of a human body. About 80% of the earth’s surface (ie 80% of the total 500 million hectares in area) is covered by water. Out of the estimated 1,11 million km3 of the total water present on earth, only 33,400m3 of water is available for drinking, agriculture domestic and industrial consumption. The rest of the water is locked up in oceans as salt water, polar ice caps and glaciers and underground. Owing to increased industrialization on one hand and exploding population on the other, the demands of water supply have been increasing tremendously.
However, consideration, part of this limited quality of water is contained by sewage, industrial waste and a wide array of synthetic chemicals. The menace of water-borne diseases and epidemics still threatens the well being of population, particularly in under-developed and developing countries.
Thus, the quality as well as the quantity of clean water supply is of importance for the welfare of mankind (cheremissinof 1981).
1.1 INDUSTRIAL WASTEWATER
An industry is a place or an establishment for the production or making of things (products) in factories or companies. Industry uses large volume of water in its manufacturing and supporting operations. Indeed, the chemical petroleum and other industries uses a large volume of water that fare exceeds the combined volume of other raw materials, finishing operation generally draw appreciable quantities of water. But it is not the water entering industrial works that actually becomes part of the manufactured product, a small fraction of the water is consumed or lost by evaporation while the larger fraction is not used or is employed non-consumptively.
The water that is employed non-consumptively becomes spent water and many contain mainly waste (Pollutants or contaminants) and that is the reason it is called wastewater. When untreated wastewater accumulates and is allowed to go septic, the decomposition of the organic matter it contains will lead to nuisance condition including the production of mal-odorous gases. It can also contain pathogenic micro organisms that dwell in the human intestinal tract and nutrients which can stimulate the growth of aquatic plant and toxic compounds that potential may be mutagenic and carcinogenic. For these reason, the immediate and nuisance free removal of wastewater from its source of generation, followed by treatment, reuse or disposal into the environment is necessary to protect public health and the environment.
1.2 DEFINITION OF WASTEWATER TREATMENT AND INDUSTRIAL WASTEWATER TREATMENT
wastewater treatment is the collection, processing, treating, recycling or disposal of waste material in water (usually waste produced by human activities) in order to reduce their effect on human health and the environment.
Industrial wastewater, treatment covers the mechanism and processes used to treat waters that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-uses.
It can also be defined as the application of scientific and advanced methods in the recycling or disposal of unwanted water or combination of liquid removed from factories or companies like chemical and petroleum industries (Bachok et al, 1967).
1.3 TO TREAT, REUSE AN DISPOSE WASTE WATER, IT IS NECESSARY TO HAVE KNOWLEDGE OF THE FOLLOWING
i. constituent of wastewater.
ii. Effect of these constituent when water is dispersed into the environment.
iii. The transformation and long-term fate of these constituents in the treatment processes.
iv. Treatment methods that can be used to remove the
constituent found in the wastewater.
v. Methods for beneficial use or disposal of the solid generated by the treatment system.
1.3.1 CONSTITUENT OF WASTEWATER FROM CHEMICAL AND PETROLEUM INDUSTRIES
Chemical industry comprise the companies that produce industrial chemicals while a petroleum industry is an industry or company that refines oils and petro-chemical products.
The component of their waste can be classified into the following:
i. Organic waste such as oxygen demanding waste, disease causing waste, synthetic organic compounds, and oil pollutant/ waste.
ii. Inorganic waste: this comprise of mineral acids, inorganic salts, finely divided metals, or metal compounds, trace elements, cyanides, sulphate, nitrates, etc.
iii. Suspended solids and sediments are mostly contributed by soil erosion by natural processes, agricultural development, strip mining and construction activities.
1.3.2 Effects of these constituents
Oxygen demanding waste causes depletion of dissolved oxygen (2.0) from the water and these is harmful to aquatic organisms.
Disease causing waste such pathogenic microorganism cause dangerous water borne disease like cholera, typhoid, dysentery and polio. Synthetic organic compounds such as peticides, insecticides and other chemicals are very toxic to plants and animals and humans. Some of them causes offensive, odours and tastes in water.