BYElegbeleye Oladipo A

EFFECT OF INDUSTRIAL EFFLUENTS ON RECEIVING WATERS

EFFLUENT: Effluent is defined by the United States Environmental Protection Agency as "wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged into surface waters".

INDUSTRIAL EFFLUENT: refers to wastes discharged from the industries into the surface water,

INTRODUCTION

Point Sources of Water Pollution; These are the sources in which the effluents produced are discharged directly into the river or stream.These include municipal sewage treatment plant discharges and industrial plant discharges.

Non-Point Sources of Water Pollution: They are contaminants which are not directly discharged into the water bodies. Examples of non-point source water pollution include agricultural and urban runoff, and runoff from mining, and construction sites.

SOURCES OF WATER CONTAMINATION

Biochemical Oxygen Demand (BOD); It is the amount of oxygen required by the micro organisms to decompose the organic matter in the water.Human and animal wastes as well as effluents from industries processing plant or animal products contain a mixture of complex organic substances such as carbohydrates, proteins and fats as their major pollution load. These substances are readily biodegradable and when introduced into the environments are quickly decomposed through the action of natural microbial populations.

Chemical Oxygen Demand (COD): It the measure of the total quantity of oxygen required to oxidize all organic material into carbon dioxide and water.

EFFECTS ON WATER QUALITY

Nutrients; The availability of plant nutrients, particularly nitrogen and phosphorus are important determinants of the biological productivity of aquatic ecosystems. In warm weather, nutrients stimulate rapid growth of algae and floating aquatic weeds. The water often becomes opaque and has unpleasant tastes and odours.

Turbidity :Turbidity is an expression of the optical property that causes light to be scattered and absorbed rather than transmitted in straight lines through a water sample. Light attenuation by suspended particles in water has two main types of environmental impact: reduced penetration into water of light for photosynthesis and reduced visual range of sighted animals and people

CONT.

Electrical Conductivity (EC): Electric Conductivity or Total Dissolved Solids is a measure of how much total salt (inorganic ions such as sodium, chloride, magnesium, and calcium) is present in the water. If the conductivity of a stream suddenly increases, it indicates that there is a source of dissolved ions in the vicinity.

pH; The pH is a measure of the acid balance of a solution and is defined as the negative of the logarithm to the base 10 of the hydrogen ion concentration (UNESCO, WHO & UNEP, 1996).

CONT.

Heavy metals (Lead, Copper and Cadmium, etc) :Heavy metals (Pb, Cu, Cd) are among the major toxic pollutants in surface water (Chino, 1981). These have been found to be a problem in streams abutted by catchments with factories dealing with tanning, smelting, welding, renovation, manufacture and disposal of car batteries, petroleum and oil. Heavy metals are very toxic, when consumed causes many effect to health. Some of these metals are cacogenic which affect the cell.Temperature: Most waste water have higher temperature than natural water. When discharged into a water bodies it increases the temperature of the water causing an unfavorable condition for aquatic life, which tend to the migration of some aquatic animals and eventually death.

CONT.

EFFLUENTS DISCHARGE

EFFECT ON AQUATIC LIFE

HEAVY METALS STANDARD

SALINITY: The ions responsible for salination are: Na+, K+, Ca2+, Mg2+ and Cl−. As the Na+ (sodium) predominates, soils can become sodic. Sodic soils present particular challenges because they tend to reduce plant yield and very poor soil structure which limits or prevents water infiltration and drainage.Salinity from irrigation can occur over time wherever irrigation occurs, since the water contains some dissolved salt.

Heavy metals like( Lead, Copper and Cadmium, etc) when contained in an irrigation water reduces the fertility of the soil causing reduced production of plant, sometimes causes death.

EFFECTS ON SOIL

Oil and Grease Removal; Some industrial effluents contain oil and grease which makes it hard for the conventional water treatment to remove these pollutants except some advanced treatments are applied.

Some wastewater may be muddy, when transported to the water treatment plant it settles in the transport system and causing plugging in the tanks.

Effluent with high organic matter contains low dissolve oxygen in which a proper aeration must be done before treatment.

EFFECT ON WATER TREATMENT

Limits should be imposed on how much effluent to be discharged.

Standards should be imposed on the effluent characteristics to be discharged into the river or streams.

Industries must treat their waste before they discharged it to the rivers or streams.

Environmental protection agencies should monitor the conditions of the water bodies.

MEASURES TO BE TAKEN

Heavy metals in the effluents can not be removed by conventional treatment. An advanced process must be applied to remove these metals which need more process to be done and more cost of treatment.

CONT.

Industrial effluents pose many threats to the ecosystem causing many harmful effect to the habitats. Proper environmental remediation should be taken to save the environmental impacts caused by these activities.

CONCLUSION