Water Pollution and its Control

WATER POLLUTION AND ITS CONTROL

• Human activities have led to the abuse and pollution of water bodies worldwide, with various types of waste being disposed into them.
• Despite water's cleansing properties, continuous pollution poses threats to water bodies, which are essential not only for human life but also for other living organisms.
• Human beings often try to wash away various types of waste through rivers and drains, including:

- Industrial waste: Chemicals, heavy metals, and toxins discharged from industrial processes.

- Agricultural runoff: Pesticides, fertilizers, and animal waste washed into water bodies from agricultural fields.

- Municipal waste: Household sewage, garbage, and plastic waste disposed of improperly.

- Urban runoff: Pollutants washed off from streets, roads, and urban areas during rainfall, including oils, chemicals, and litter.

• Pollution has led to the degradation of ponds, lakes, streams, rivers, estuaries, and oceans in various parts of the world.
• Contaminated water can harm aquatic ecosystems, affecting fish and other aquatic life, as well as posing risks to human health when used for drinking or recreational purposes.
• Recognizing the importance of maintaining clean water bodies, the Government of India enacted the Water (Prevention and Control of Pollution) Act in 1974.
• This legislation aims to safeguard water resources by regulating and controlling pollution through measures such as setting water quality standards, implementing pollution control measures, and monitoring water quality.
• Efforts to control water pollution include:

- Treatment of industrial and municipal wastewater before discharge into water bodies.

- Implementation of pollution prevention and control technologies in industries to reduce emissions and effluents.

- Adoption of sustainable agricultural practices to minimize runoff of pesticides and fertilizers.

- Promotion of waste management strategies such as recycling and proper disposal to prevent litter and garbage from entering water bodies.

- Restoration and conservation of aquatic ecosystems through measures such as wetland restoration and riparian buffer zones.

Domestic Sewage

• Domestic sewage consists of wastewater generated from households, including water used for bathing, washing, and flushing toilets.

• It also includes sewage from hospitals, which may contain pathogenic microorganisms.
• Domestic sewage primarily contains biodegradable organic matter, dissolved salts (such as nitrates and phosphates), and various nutrients.
• It may also contain pathogenic microorganisms, detergents, and other pollutants.
• Treatment of Domestic Sewage:

- Sewage treatment plants are used to treat domestic sewage before discharge into water bodies.

- Treatment processes aim to remove solids, dissolved salts, and harmful microorganisms from sewage.

- Solids are relatively easy to remove, while dissolved salts and organic compounds pose greater challenges.

- Biochemical Oxygen Demand (BOD) is used to estimate the amount of biodegradable organic matter in sewage water, indicating the level of pollution.

- Treatment processes involve biological, physical, and chemical methods to break down organic matter and remove pollutants.

• Impact of Domestic Sewage on Water Bodies:

- Discharge of untreated domestic sewage into water bodies can lead to oxygen depletion due to microbial decomposition of organic matter.

- Decreased dissolved oxygen levels downstream from sewage discharge points can result in fish mortality and other aquatic ecosystem disturbances.

- Excessive nutrients in sewage can cause eutrophication, leading to algal blooms, foul odors, and deterioration of water quality.

Biomagnification

• Biomagnification refers to the process by which certain toxic substances accumulate in organisms at higher trophic levels in a food chain.
• Mechanism:

- Toxic substances, such as heavy metals or organic compounds, accumulate in organisms that consume contaminated food or water.

- These substances cannot be metabolized or excreted effectively, leading to their accumulation in tissues.

- As organisms are consumed by predators, the concentration of toxic substances increases at each successive trophic level, resulting in biomagnification.

• Example:

- DDT (dichlorodiphenyltrichloroethane) is a pesticide that undergoes biomagnification in aquatic food chains.

- Starting at low concentrations in water, DDT accumulates in plankton, which are consumed by small fish.

- Small fish are then consumed by larger fish, leading to further accumulation of DDT in their tissues.

- At the top of the food chain, predators such as fish-eating birds may experience high concentrations of DDT, leading to adverse effects such as thinning of eggshells and population declines.

Eutrophication

• Eutrophication is the natural process of aging in a lake due to the enrichment of nutrients, primarily nitrogen and phosphorus, in its water.
• Natural Process:

- In a young lake, the water is cold and clear, with limited life support.

- Over time, nutrients such as nitrogen and phosphorus are introduced into the lake through streams, promoting the growth of aquatic organisms.

- As the lake becomes more fertile, plant and animal life flourishes, and organic matter accumulates on the lake bottom.

- Over centuries, sediment and organic debris build up, causing the lake to become shallower and warmer.

- Warm-water organisms replace cold-water species, and marsh plants begin to colonize the shallows.

-Eventually, the lake may transform into a bog and eventually into land.

• Cultural or Accelerated Eutrophication:

- Human activities, such as industrial and domestic waste discharge, can accelerate the natural aging process of lakes.

- Pollutants like nitrates and phosphates from sewage, agricultural runoff, and industrial wastes overstimulate algae growth, leading to algal blooms and foul odors.

- Excessive growth of algae robs the water of dissolved oxygen, causing fish kills and disrupting aquatic ecosystems.

- Pollutants may also poison fish populations, further depleting dissolved oxygen levels and choking the lake.

• Impact of Heated Wastewaters:

- Thermal wastewater from electricity-generating units, such as thermal power plants, can exacerbate eutrophication.

- Heated wastewater reduces the number of temperature-sensitive organisms and may enhance plant and fish growth in cold areas.

- However, it can also damage indigenous flora and fauna, disrupting the ecological balance of aquatic ecosystems.

Algal Bloom

• An algal bloom refers to a rapid and excessive growth of algae in water bodies, often fueled by nutrient enrichment.
• Excessive nutrients, such as nitrogen and phosphorus, promote the growth of algae, leading to the formation of algal blooms.
• Pollution from sources such as sewage, agricultural runoff, and industrial waste can contribute to algal bloom formation.
• Algal blooms can lead to the deterioration of water quality, foul odors, and changes in aquatic ecosystems.
• Some algae species may produce toxins harmful to humans and animals, leading to health risks and fish mortality.
• Excessive algal growth can also deplete dissolved oxygen levels in water bodies, leading to fish kills and disruptions in aquatic food chains.

Integrated Wastewater Treatment: A Case Study of Arcata

• Location: Arcata, northern coast of California.
• Collaboration: Biologists from Humboldt State University collaborated with the townspeople.
• Process:

Stage 1: Conventional sedimentation, filtering, and chlorine treatments are applied to the wastewater.

Stage 2: Innovative approach involving the creation of a series of six connected marshes covering 60 hectares of marshland.

• Marsh Treatment: Marshes are seeded with appropriate plants, algae, fungi, and bacteria to neutralize, absorb, and assimilate pollutants.
• Natural Purification: As water flows through the marshes, it undergoes natural purification.
• Biodiversity: The marshes serve as a sanctuary, supporting a high level of biodiversity, including fishes, animals, and birds.
• Citizens' Involvement: Friends of the Arcata Marsh (FOAM) group is responsible for maintaining and safeguarding the project.
• Ecological Sanitation

Concept: Sustainable system for handling human excreta without using water, utilizing dry composting toilets.

Benefits:

Practical, hygienic, efficient, and cost-effective solution for human waste disposal.

• Human excreta can be recycled into a resource (natural fertilizer), reducing the need for chemical fertilizers.
• Implementation: Working 'EcoSan' toilets are found in many areas of Kerala and Sri Lanka.

Solid Waste

• Solid wastes encompass all materials discarded as trash. Municipal solid wastes originate from homes, offices, stores, schools, and hospitals, managed by municipal authorities.
• Municipal solid wastes include paper, food wastes, plastics, glass, metals, rubber, leather, and textiles.
• Disposal Methods:

- Burning: Burning reduces waste volume but is often incomplete, leading to air pollution. Open dumps attract rodents and flies.

- Sanitary Landfills: Adopted to replace open dumps, wastes are compacted and deposited in trenches, covered with soil daily.

• Challenges:

- Overflowing Landfills: Rapid urbanization leads to increased garbage generation, filling up landfill sites.

- Pollution Risks: Chemical seepage from landfills poses threats to underground water resources.

• Solutions:

- Waste Categorization: Waste sorting into biodegradable, recyclable, and non-biodegradable categories is crucial.

- Recycling and Reuse: Promote recycling and reuse of materials, facilitated by kabadiwallahs (scrap dealers) and rag-pickers.

- Biodegradable Treatment: Biodegradable waste can be composted in pits for natural decomposition.

- Environmental Awareness: Increasing awareness about environmental issues is essential for sustainable waste management practices.

- Plastic Waste Management: Reducing Plastic Use: Encourage the reduction of non-biodegradable plastic usage through eco-friendly alternatives.

- Government Initiatives: State governments advocate for reducing plastic usage and promoting eco-friendly packaging.

- Hospital Waste Management:

Hazardous Waste Disposal: Hospitals produce hazardous wastes containing disinfectants, harmful chemicals, and pathogens, necessitating proper treatment and disposal, often through incineration.

- Electronic Waste Management:E-waste Disposal: Electronic wastes, including irreparable computers and gadgets, are buried in landfills or incinerated.

• Recycling Challenges: Developing countries face challenges in recycling e-wastes, often involving manual labor and exposing workers to toxic substances.
• Environmentally friendly recycling practices are crucial for managing e-wastes effectively.

Remedy for Plastic Waste: Polyblend in Road Construction (Case study)

• Innovator: Ahmed Khan, a plastic sack manufacturer in Bangalore, devised a solution to tackle plastic waste accumulation.
• Solution: Polyblend, a fine powder of recycled modified plastic, is developed by Khan's company. It is mixed with bitumen for road construction.
• Collaboration: Khan collaborated with R.V. College of Engineering and Bangalore City Corporation to test Polyblend's effectiveness.
• Benefits:

- Enhanced Properties: Polyblend-bitumen blends improve bitumen's water repellent properties, increasing road lifespan by threefold.

- Utilization of Waste: Polyblend utilizes plastic film waste, offering a solution to the plastic waste problem.

- Economic Incentive: Khan offers higher rates (Rs. 6 per kg) to rag pickers for plastic waste compared to the previous Rs. 0.40 per kg.

• Implementation: By 2002, over 40 kilometers of roads in Bangalore were laid using Polyblend.
• Impact: Khan's innovation helps alleviate the burden of plastic waste and offers a sustainable solution for road construction.
• Continued adoption of innovations like Polyblend can mitigate plastic waste accumulation and its adverse environmental effects.

Soil Pollution

• Soil pollution refers to the contamination of soil with harmful substances, impacting soil fertility and ecosystem health.
• Agro-chemicals like inorganic fertilizers and pesticides, extensively used in the green revolution, have led to severe soil pollution.
• Pesticides, herbicides, and fungicides, while enhancing crop production, pose toxicity risks to non-target organisms in soil ecosystems.
• Agro-chemicals can biomagnify in terrestrial ecosystems, posing risks to higher trophic levels.
• Overuse of chemical fertilizers can lead to eutrophication in aquatic ecosystems, disrupting the balance and health of these systems.
• The current agricultural challenges are significant due to soil pollution, affecting soil fertility, crop health, and overall agricultural sustainability.
• Soil pollution from agro-chemicals poses serious threats to soil health and ecosystem balance.

Case Study: Integrated Organic Farming by Ramesh Chandra Dagar

• Ramesh Chandra Dagar, a farmer in Sonipat, Haryana, practices integrated organic farming, a cyclical, zero-waste approach to agriculture.
• Zero-Waste Procedure: Integrated organic farming involves cycling waste products from one process as nutrients for other processes, maximizing resource utilization and production efficiency.
• Bee-keeping: Utilized for pollination and honey production, supporting crop health.
• Dairy Management: Cattle excreta (dung) used as natural manure for crops, eliminating the need for chemical fertilizers.
• Water Harvesting: Collecting rainwater for irrigation, ensuring water sustainability.
• Composting: Crop waste converted into compost, serving as natural fertilizer or generating natural gas for energy needs.
• Cultivation of crops in synergy with other components, ensuring a balanced ecosystem.
• Dagar's integrated organic farming approach is highly economical and sustainable, promoting soil health, crop productivity, and environmental conservation.
• Dagar has established the Haryana Kisan Welfare Club to spread awareness and support among farmers, with a membership of 5000 farmers, advocating for the adoption of integrated organic farming practices.
• Dagar's initiative demonstrates the feasibility and benefits of integrated organic farming in achieving agricultural sustainability and environmental conservation.

Radioactive Wastes

• Radioactive wastes consist of materials contaminated with radioactive substances, posing significant health and environmental risks.
• Nuclear energy, once seen as a clean energy source, poses significant challenges due to the generation of radioactive wastes.
• Incidents like Three Mile Island and Chernobyl highlight the risk of accidental radioactive leaks, causing environmental and health hazards.
• Effective disposal of radioactive wastes is a critical concern due to their damaging effects on organisms and potential for causing mutations and cancer.
• Radiation emitted by nuclear waste is highly damaging, with even low doses posing health risks such as cancer and other disorders.
• Disposal Challenges:

- Recommended disposal methods involve storing pre-treated nuclear waste in shielded containers buried deep underground. However, public opposition to this method is significant.

Reasons for opposition to deep burial disposal methods may include concerns about:

- Safety: Doubts about the long-term safety and stability of underground storage facilities.

- Environmental Impact: Fear of groundwater contamination and other environmental consequences.

- Health Risks: Anxiety about potential health risks to future generations from radioactive leaks or releases.

• Effective management of radioactive wastes requires careful consideration of disposal methods that prioritize safety, environmental protection, and public trust, while addressing concerns and ensuring transparency in decision-making processes.