Environmental Issues: Wastewater Management

Waste Water and Environmental Impact

• Solids in wastewater are relatively easy to remove; however, dissolved salts like nitrates and phosphates, toxic metal ions, and organic compounds are more challenging.
• Domestic sewage contains biodegradable organic matter that decomposes rapidly through bacterial activity.
• Biochemical Oxygen Demand (BOD) measures the amount of biodegradable organic matter; high BOD indicates a high level of organic waste and consequently low dissolved oxygen.
• Following sewage discharge, dissolved oxygen decreases significantly downstream, leading to fish mortality and harm to aquatic life.
• Excessive nutrients in water can cause algal blooms, resulting in poor water quality and further fish mortality; some algae can be toxic to humans and animals.
• Certain floating plants previously introduced for ornamental purposes have proliferated, obstructing waterways and complicating waste management.

Agro-Chemicals Usage and Organic Farming

• The green revolution spurred increased use of inorganic fertilizers and pesticides which are harmful to non-target soil organisms.
• Chemical fertilizers can lead to eutrophication in aquatic ecosystems, showing the detrimental effects of agricultural chemicals.
• Integrated organic farming promotes a cyclical process where waste from one system becomes a resource for another, enhancing sustainability.
• Ramesh Chandra Dagar in Haryana practices this approach, utilizing bee-keeping, dairy, and composting to create a zero-waste system, reducing reliance on chemical fertilizers.

Radioactive Waste and Energy

• Nuclear energy poses significant risks including accidental leaks and the challenges of safely disposing of radioactive waste.
• Nuclear waste emits high levels of radiation, which may cause mutations and increase cancer risks.
• Proper disposal methods advocate for burying treated nuclear waste in shielded containers deep underground, though public opposition persists.

Greenhouse Effect and Global Warming

• The greenhouse effect is a natural phenomenon essential for maintaining Earth’s temperature; without it, average temperatures would be significantly lower.
• Solar radiation is partly reflected and absorbed by the atmosphere, with a portion heating the Earth’s surface.
• Increased greenhouse gases, primarily from human activities, enhance the greenhouse effect, leading to climate change and associated environmental challenges.

Deforestation and Its Consequences

• Deforestation involves converting forested areas to non-forested land, with an estimated 40% loss in tropical forests compared to only 1% in temperate regions.
• In India, forest cover dropped from 30% to 21.54% in the last century, conflicting with the National Forest Policy's recommendations for maintaining forest cover.
• Human activities driving deforestation include agricultural expansion, timber harvesting, and slash-and-burn practices.
• Deforestation increases atmospheric CO2 levels, impacting climate and mitigating carbon sequestration benefits of forests.

Summary of Environmental Issues

• Pollution from air, water (domestic sewage, industrial waste), soil (agricultural chemicals), and solid waste presents diverse environmental challenges.
• Eutrophication from sewage nutrients leads to decreased dissolved oxygen in water bodies.
• Industrial wastewater contains toxic chemicals that endanger ecosystems, and solid waste management poses significant disposal problems.
• Global issues like greenhouse gas emissions, deforestation, and ozone depletion threaten environmental stability and health on multiple levels.