Eutrophication is the process of an overabundance of nutrients in a body of water, resulting in the abundant growth of plant life. This process is indicated by the excessive development (or bloom) of algae and plankton in a water body.It leads to excess concentration of phosphorus, nitrogen, and other plant nutrients in the aquatic ecosystem. Mitigation of eutrophication is a method to reduce the effects of the eutrophication to regain the ecosystem.They include wastewater treatment, nitrification, denitrification, diluting nitrogen and phosphorus at the source, etc. This article will explain to you about Mitigation of Eutrophication which will be helpful in preparing the Environment syllabus for the UPSC Civil Service Examination.

Eutrophication

• Eutrophication is the enrichment of natural waters with inorganic nutrients, resulting in an increase in the production of algae and macrophytes.
• Eutrophication is the reaction of the aquatic ecosystem to the addition of nutrients such as nitrates and phosphates, either naturally or intentionally.

Process of Eutrophication

Effects of Eutrophication

• Eutrophication leads to water quality degradation and an increase in the biological oxygen demand (BOD) in water bodies.
• Eutrophication leads to the transformation of the body of water from an aquatic ecosystem to a terrestrial ecosystem.

Effects of eutrophication

• Eutrophication leads to excess growth of algae blooms in the water body.
• Algal blooms obstruct sunlight penetration, resulting in the mortality of aquatic plants and, as a result, oxygen replenishment.
• It also leads to an increase in invasive species in the water bodies due to an increase in nutrient levels in the water bodies.
• It also leads to loss of coral reefs in water bodies due to decrease in water transparency.
• It leads to an increase in the biomass of epiphytic and benthic algae.
• The species composition of macrophytes and their biomass undergo significant modifications.
• The water loses its transparency and takes on an unpleasant odour and colour. It becomes tough to treat this water.
• Dissolved oxygen in the water body is depleted.
• The aesthetic value of the water body reduces significantly.
• Eutrophication decreases the biodiversity of the ecosystem .
• It increases the water toxicity which makes it not fit for drinking and economic purposes.
• It adversely affects the vertical structure of any aquatic ecosystem like lakes and ponds .

Causes of Eutrophication

Industrial waste

• Industries play a vital role in the eutrophication process.
• They enrich the water bodies with industrial effluents and compounds of industrial waste.
• This depletes the quality of the water bodies and reduces biodiversity.

Industrial waste

Agriculture Fertilizers usage

• The excess use of fertilizer used in agriculture is the primary cost of eutrophication.
• The fertilizers used in agriculture are subject to runoff to the nearby water bodies , thereby increasing the nutrient level.
• This promotes the growth of algae bloom and other microorganisms in the water bodies.

fertilizers runoff

Untreated Sewage

• Untreated sewage and waste from households are directly fed into nearby water bodies. This results in contamination of the water body by organic pollutants.
• These organic pollutants when dissolved in water and decomposed lead to increased nutrient level and reduced oxygen level in the water bodies.
• This results in contaminations and eutrophication of water bodies.

untreated sewage

Primary role of phosphorus in eutrophication

• Phosphorus is one of the most important limiting elements for plant growth in freshwater habitats.
• Phosphates have a tendency to adhere to the soil and are transferred with it.
• As a result, soil erosion plays a significant role in the phosphorus enrichment of water bodies.
• This leads to increased nutrient content in the water bodies.

Mitigation of eutrophication

1. Treating the industrial waste

• Industrial waste should be treated before discharges into the nearby water bodies.
• Advanced Oxidation Processing, distillation, adsorption, vitrification, incineration, chemical immobilization, and landfill disposal are some of the methods used.
• Other methods like wastewater treatment can significantly reduce the chemical content in the water before discharging to nearby water bodies.

industrial waste treatment

2. Fertilizers

• Use of organic fertilizers and encouraging organic farming can act as an alternative to chemical fertilizers, which increases the speed of eutrophication (Organic fertilizers include manure, compost , rock phosphate, chicken litter etc.)
• Nitrogen and phosphorus elements from the soil increase the rate of eutrophication in water bodies.
• A significant amount of P from agricultural fields is lost to rivers, lakes, and reservoirs via leachate and runoff, eventually ending up in the marine ecosystem.

organic fertilizer

3. Creating buffers zone

• The buffer zone creates an avenue to deposit the sediments before entering into the water bodies, thus preventing eutrophication. They act as a filter to reduce pollution.

buffer zone

4. Other methods

Other methods like chemical precipitation, which reduces the extra phosphorus in water bodies, treating algae with Alum, lime, iron, and sodium aluminate can also be used in the mitigation of Eutrophication.

Conclusion

The mitigation process in India needs to be more inclusive to recover the water bodies.

Structural changes combined with technological advancement must be undertaken to save the aquatic ecosystem. Other initiatives like better management of water bodies with regular survey and inspection can bring into light a speedy solution for mitigation eutrophication.