Page 30 - Materials Chemistry, Second Edition

Environmental and Health Effects Due to the Usage of Wastewater 11

sources. Wastewater is composed of inorganic chemicals, organic chemicals, harm-
ful gases, and dissolved oxygen. It consists of natural organic compounds such as
carbon, oxygen, hydrogen, and nitrogen. The primary components present in waste-
water are carbohydrates (25%–50%), proteins (40%–60%), and oils (10%). It also
contains iron, sulfur, and phosphorus. These organic compounds present in waste-
water are easily biodegradable, whereas some of the synthetic organic compounds
present in wastewater cannot be composted easily, which complicates the wastewa-
ter treatment. Inorganic compounds such as chloride, nitrogen, sulfur, phosphorus,
hydrogen ions, and heavy metals are present in wastewater. Plant forms such as algae
and other organisms use these inorganic substances, such as carbon, phosphorus,
and ammonia-nitrogen, as a source of food. These compounds are capable of affect-
ing the organisms at even minute concentrations. Nutrients such as phosphorus and
nitrogen in higher concentrations affect the water resources by causing algal bloom,
which causes the destruction of aquatic organisms. Undesirable levels of nitrogen
and phosphorus in the water stream cause excess algal growth, which creates an
oxygen deficient environment and destroys the aquatic organisms. The monitoring
of nutrient levels in wastewater is essential to inhibit the undesirable growth of phy-
toplankton in water.

1.4.3 biological cHaracTerisTics of WasTeWaTer
The effluents discharged from industry contain harmful pathogens: bacteria, proto-
zoa, and viruses. Bacteria are notable microorganisms that help in the decomposition
of organic compounds in wastewater using the oxygen in the wastewater. Measuring
the quantity of microorganisms is one of the important parameters in checking the
effectiveness of wastewater treatment. The acceptable range of microbial load in
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the wastewater is 10 –10 mL . Harmful pathogens such as intestinal viruses can
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easily be transmitted through water and can cause harmful diseases. The harmful
pathogens should be removed from the wastewater during treatment to avoid the
transmission of dreadful diseases (Muttamara, 1996). The biological system is an
important part of the wastewater, as it helps in the breakdown of complex substances
in the wastewater. The biological characteristics of the wastewater should be clearly
understood to decide the type of wastewater treatment. Thus, these are the physi-
cal, chemical, and biological characteristics of wastewater, which help to design the
wastewater treatment system. The environmental effects of wastewater are discussed
in detail in the following section.

1.5 IMPACTS OF WASTEWATER ON ENVIRONMENT
Wastewater is well known for both its beneficial activities and its drawbacks. As
wastewater contains many essential nutrients for the growth of plants, it is used as
a growth enhancer in agriculture. On the other hand, wastewater poses some seri-
ous negative impacts to the environment (Akpor and Muchie, 2011). Effluent dis-
charge releases different contaminants into the fresh water resources. The bulk of
fresh water is profoundly devoured by humans for drinking and other domestic pur-
poses. The blending of industrial contaminants into the water resources destroys the