Water Quality and Pollution

Biochemical oxygen demand is the measure of oxygen required by aerobic decomposers for biochemical degradation of the organic materials. BOD indicates the degree of organic pollutants present in water.

Organic matter in sewage consists of biological materials like food waste and human waste, which can be broken down by microorganisms, making it biodegradable.

Point sources of pollution are identifiable, localized sources such as pipes or specific treatment plant outlets. In contrast, diffused or non-point sources are spread out over a large area.

A low pH in sewage indicates acidic conditions, which are often the result of the fermentation of organic matter, commonly referred to as septic conditions.

Anaerobic bacteria are organisms that thrive in environments lacking free dissolved oxygen, utilizing other compounds for respiration.

Turbidity is the cloudiness of a fluid caused by large numbers of individual particles, specifically suspended and colloidal solids that scatter light.

Strong sewage contains a higher concentration of organic and inorganic matter, which increases the number of suspended and colloidal particles, thereby increasing turbidity.

Sewage treatment is necessary to prevent the pollution of water bodies and to protect aquatic life from the harmful effects of untreated waste.

The wastewater mixture will contain large numbers of microscopic organisms, mostly bacteria that are capable of consuming the organic component (fats, proteins, and carbohydrates) of the mixture and bringing about rapid changes in the wastewater. The solid components of wastewaters actually represent a very small part of most discharges, usually less than 0.1% by weight. However, it is this small component of the wastewater that presents the major challenges in wastewater treatment, operation, and disposal.

Contamination of water reservoir with sewage water leads to increased level of phosphate in water. Due to increased level of phosphate algae starts growing on it. This decreases the dissolved oxygen level in water thus all the aquatic lives can't survive and leads to mortality. This is called eutrophication.

Sewage treatment constitutes of 3 stages primary, secondary and tertiary. BOD i.e biological oxygen demand decreases during secondary stage. This makes water permissible to let into natural water resources.

Eichhornia crassipes, commonly known as common water hyacinth, is an aquatic plant native to the Amazon basin and is often a highly problematic invasive species outside its native range. When not controlled, water hyacinth will cover lakes and ponds entirely which affects water flow and blocks sunlight from reaching native aquatic plants which often die. The decay processes deplete dissolved oxygen in the water, often killing fish (or turtles).

Estuaries are areas where freshwater from rivers meets and mixes with saltwater from the ocean, creating a nutrient-rich environment that acts as a trap for sediments and organic matter.