Mains:GS I – Urbanization, their problems and their remedies
Why in News?
In India, the water and wastewater sector, particularly the reuse of treated wastewater, has recently gained attention, especially in water-stressed urban areas.
What is waste water?
Waste water – It is used water from homes, industries, and other human activities that contains pollutants, making it unsafe for its original use or for discharge into the environment without treatment.
It can also include stormwater runoff and infiltration from sewer systems.
Indian scenario – According to the Central Pollution Control Board, Indian cities generate over 72,000 million litres per day (MLD) of sewage.
Contaminants – Common contaminants include human waste, food scraps, chemicals, pathogens, and heavy metals.
Issues – Wastewater is a significant environmental and health concern as it threatens aquatic ecosystems and human health if improperly managed or discharged untreated.
What is waste water management?
Waste water management – It is the process of collecting, treating, and safely reusing or disposing of wastewater to protect public health and the environment.
Need – India, which supports nearly 18% of the world’s population with only 4% of global freshwater resources, faces acute stress on its water systems.
Between 1951 and 2024, there has been a decline of 73% in per capita surface water availability in the country.
The rising water scarcity across the world has drawn attention to wastewater treatment and reuse.
India’s capacity – The installed treatment capacity is less than 32,000 MLD.
Only 28% of urban wastewater in India is treated, while the remaining 72% flows untreated into water bodies and land.
Potential – Wastewater management can be a solution to bridge the gap between water demand and supply.
What are the sources and impact of wastewater?
Major sources – Wastewater in India primarily originates from multiple sources, the most significant being
Domestic sewage
Industrial effluents
Agricultural run-off
Domestic sewage – It constitutes the largest share, which flows directly into rivers and lakes.
For example, Yamuna receives 641 million litres of untreated sewage per day, turning the river ecologically dead.
Industrial discharges - It adds another layer of pollution.
According to the Pollution Control Board’s Data, there are 3,519 highly polluting industries in the country that discharge wastewater into India’s rivers.
The Ganga basin is highly affected due to industrial pollution with tanneries in Kanpur and distilleries in Bihar being major sources.
These effluents often contain heavy metals, dyes, and toxic chemicals, posing long-term risks to human and ecological health.
Agricultural run-off – It is also a critical source of nutrient pollution that causes eutrophication (the process of water enrichment with excess nutrients, primarily phosphorus and nitrogen) in water bodies.
For instance, the Vembenad Lake in Kerala, a Ramsar Site, has witnessed a declining fish population due to nutrient pollution.
Impacts – Wastewater is not only an environmental issue, but a serious public health concern too.
Contaminated water is a major source of waterborne diseases such as diarrhoea, cholera and dysentery and has been linked to the spread of anti-microbial resistance.
Around 37.7 million Indians are affected by waterborne diseases annually.
It also increases the cost of potable water treatment and affects livelihoods dependent on clean water, such as fisheries and tourism.
What are the legal and institutional framework?
The Water (Prevention and Control of Pollution) Act, 1974 – It was the first comprehensive legislation aimed at preventing and controlling water pollution.
It established central and state pollution boards, and empowered them to set effluent standards, monitor compliance, and take corrective action.
The Central Pollution Control Board (CPCB) – It issues guidelines on the treatment of wastewater, especially sewage water.
National Water Policy, 2012 – It has stressed integrated water resource management and explicitly recognised the need for wastewater recycling and reuse.
Schemes and initiatives – Many schemes have also been taken to tackle river pollution
National Mission for Clean Ganga – It is also known as the Namami Gange programme, along with other river rejuvenation programmes aimed at restoring polluted river stretches identified by CPCB.
Swachh Bharat Abhiyan, AMRUT and the Smart Cities Mission – These also promote wastewater reuse facilities in urban areas.
These initiatives combine infrastructure development for sewage treatment with efforts at public participation and institutional coordination.
The Draft Liquid Waste Management Rules, 2024 – More recently, this were notified under the Environment Protection Act, 1986.
It outlines measures to minimise waste generation, establish proper collection systems, ensure effective treatment, and promote the reuse or utilisation of treated wastewater and sludge.
The draft rules align with the circular economy approach by promoting wastewater as a resource rather than a liability.
What are the available and evolving technological interventions?
Activated Sludge Process (ASP) – It is a common aerobic method involving removal of suspended solids and organic contaminants through the activity of microorganisms such as bacteria, fungi and algae.
The Sequential Batch Reactor (SBR) – It is an advanced wastewater treatment process that operates in batch mode through sequential phases.
Its operational flexibility makes it one of the highly used methods in sewage wastewater treatment applications.
Up-flow Anaerobic Sludge Blanket (UASB) – It is a conventional method and it is low-cost and energy-efficient.
Membrane Bioreactor (MBR) – It integrates biological treatment with membrane filtration and produces high-quality effluent suitable for reuse in industrial and non-potable applications.
It is a suitable choice for industrial areas and high-value urban areas where the benefits of reuse outweigh the costs.
Emerging Nano-technologies – Nano filters show promise in enhancing treatment efficiency, though they are still at an experimental stage in India.
What are the critical gaps and challenges?
Enforcement gaps – The impact pf schemes has been constrained by gaps in enforcement, inadequate operation, and maintenance of treatment plants and fragmented governance.
Lack of policies and plans – Only 11 out of 28 states have formulated wastewater reuse policies, and most lack clear roadmaps for implementation.
Inefficient conventional methods – Most of these conventional methods of waste water treatment are less effective in handling complex industrial effluents and require a large space to operate.
Issues with new technologies – High installation, continuous monitoring and high energy requirements and maintenance cost remains the major obstacle.
What measures can be taken?
Comprehensive national mandate – The draft Liquid Waste Management Rules 2024, once operationalised, hold potential to standardise the treatment process and encourage reuse.
Technological interventions – Particularly SBRs and MBRs, have shown promise in improving treatment efficiency and effluent quality.
Public-private partnerships – It can also play a crucial role in financing and operating advanced treatment infrastructure.
Nature-based solutions – It includes constructed wetlands, waste stabilisation ponds, and decentralised treatment plants, are being explored as cost-effective alternatives, particularly suitable for peri-urban and rural areas.
Awareness – It is essential to overcome social resistance and build public trust in the safe use of treated wastewater, particularly for agricultural and non-potable uses.
What lies ahead?
An integrated approach combining strong regulation, advanced technologies and promotion of water reuse will be essential for making wastewater management not just an environmental mandate but also a resource recovery opportunity for India’s future.
