¨Water, water everywhere, nor any drop to drink,¨- the line from the verse ´The Rime of the Ancient Mariner´ by Samuel Taylor Coleridge exemplifies the impending global water crisis. The invaluable resource entails efficacious management to prevent depletion. In this regard, replenishing wastewater is the major thrust area, but is often recklessly relegated.
The water conservation drive has been all but a sinking ship, and the wastewater scenario is in dire straits. In this light, the rampant use of the term ´wastewater´ inevitably requires a paradigm shift towards the identification of water as a renewable resource- a resource that is worth one´s weight in gold. Each molecule of this precious compound has to be treasured- not only each drop of water imprudently spilled, but also each drop of used water running redundant. The global water crisis is slowly and steadily reaching its crescendo. The per capita availability of water has witnessed a sharp decline and thereby, water security is an issue that has begun raising alarms. H Subramaniam, Chief Operating Officer, EA Water Pvt Ltd, states, ¨The per capita availability of water in India has come down from 5500 cubic metres to 1700 cubic metres, and is estimated to come down to 1000 cubic metres by 2025. The demand for water is expected to go up from the current level of 750 billion cubic metres to about 1050 billion cubic metres by 2025.¨
To combat this issue that is looming large, desalination of sea water and wastewater treatment need to be arduously engaged in. Speaking on the water scenario, Dr PK Tewari, President, Indian Desalination Association, positively affirms, ¨Total water market in India is about 15 billion USD, and wastewater market is more than three billion USD. More than 180 small and large desalination plants are operating in the country. The finance minister has allocated more than Rs 4000 crore for water resources for FY 2015-16.¨ He however, does not deny the existing ruptures in the system.
According to Anil Pillai, Director- R&T, Business Development, High Performance Products Industries Pvt Ltd, ¨Although India holds around 17 per cent of the world population, we have only four per cent of the world´s renewable water resources available to us.¨ The Fourth World Water Development Report states that only 20 per cent of the wastewater generated globally receives proper treatment (UNESCO, 2012). Treatment capacity depends on the income level of the country; 70 per cent in high-income countries as opposed to only eight per cent in low-income countries (Sato, 2013).
Although, wastewater management has been given a high priority in the National Water Policy 2012, there is still a mammoth gap between wastewater generation and its treatment capacity. ¨There is need to close the gap between the wastewater generated and the treatment capacity on one hand, and the capacity created and the actual treatment on the other hand,¨ says Ravi Budhiraja, Chairman, Maharashtra Water Resources and Regulatory Authority (MWRRA). According to the Central Pollution Control Board (CPCB), an estimated 38,354 million litres per day (MLD) sewage is generated in major cities of India, but the sewage treatment capacity is only of 11,786 MLD. Therefore, 70 per cent of untreated sewage ends up in the water bodies. Kshitij Nilkanth, Program Manager, Energy & Environment Practice, Frost & Sullivan, asserts, ¨In India, nearly 40 percent of sewage treatment plants and pumping stations do not conform to operation and maintenance standards. Many treatment plants have also been abandoned (or are not operational) because of lack of funds for operation and maintenance or lack of technical capacity.¨
Even in a metropolis like Mumbai, operational STPs are few and far between. ¨Total estimated wastewater generated is 6433 mmb. Of the 26 municipal corporations, 18 have developed STP capacities of about 4165 mmb. We have a capacity of around 66 per cent, but how much of it is used is anybody´s guess,¨ reveals Budhiraja. Ejectors and separators are mostly dysfunctional, and there is tremendous load on the system. ¨In small towns and rural areas, the situation is worse, where sewage treatment is either absent or in the infancy state,¨ seconds Dr Sudhir D Ghatnekar, MD, Biotechnology Resource Centre.
There is no dearth of new and improved technology, but the implementation apparently gets lost in a quagmire of the bureaucracy. Dr Ghatnekar vehemently remarks, ¨There is lack of motivation among the concerned officials, even red-tapism, and the money is drained out. Even where water is being treated, they are treating and discharging it once it reaches the permissible limits, rather than recycling and reusing it.¨
Currently, there are no specific regulations or guidelines for safe handling, transport, and disposal of wastewater in the nation. ¨The existing policies for regulating wastewater management are based on certain environmental laws and certain policies and legal provisions, viz., Constitutional Provisions on Sanitation and Water Pollution; National Environment Policy, 2006; National Sanitation Policy, 2008; Hazardous Waste (Management and Handling) Rules, 1989; Municipalities Act; District Municipalities Act etc,¨ affirms Nilkanth.
Proper allocation and utilisation of funds as well as paucity of proficient manpower serve as formidable threats in the path of regulated wastewater management. Cindy Wallis-Lage, President -Water Business, Black & Veatch, points out, ¨It is important to look at different avenues for cost reduction as finance poses to be a constraint when it comes to effective wastewater management.¨ Commenting on the loopholes of the wastewater situation, Subramaniam says, ¨Execution, monitoring, and availability of trained manpower, i.e., deficit of skilled water professionals are the major bottlenecks.¨ With the urbanised community foundering, the rural areas are lagging way behind. Tewari claims, ¨A major challenge in the remote areas is that voltage fluctuation is high, and there are infrastructure limitations.¨
CENTRALISED vs DECENTRALISED
Wastewater management can be conducted through:
Conventionally, the urban wastewater management has shown a reliance on centralised systems. Industrial effluent, on the other hand, is usually treated on-site, although in some cases, a combination treatment may be sought. It is essential for wastewater management systems to be locally appropriate. The choice of approach and technologies should be context-specific, and needs to be made based on the local environment (temperature, rainfall), culture, and resources (human, financial, material and spatial).
Though favouring the decentralised system, Wallis-Lage stresses, ¨It is important to see how well it is incorporated into the existing system. The city´s size and how developed it is, along with the socio-economic culture are significant determinants. Decentralised system for the bigger cities and a more centralised system for the smaller ones could be effective.¨
Economically viable technologies with lower operating costs would be gaining eminence in the years to come. Wastewater treatment processes could be aerobic, anaerobic, or physico-chemical that can treat wastewater to almost any standard of effluent- from the simple removal of gross solids to membrane systems that can produce water suitable for drinking.
Wallis-Lage opines, ¨Technology with more and more use of membrane systems and systems low in energy- analogue system, and granular activated sludge- need to be adopted.¨ The potential of natural treatment technologies needs to be explored (i.e., natural soil aquifer and plant-root systems, without the aid of energy or chemicals), including waste stabilisation ponds, duckweed and hyacinth ponds, and constructed wetlands for wastewater management. The decentralised wastewater management treatment system (DEWATS) needs to be promoted, courtesy its cost-effectiveness, energy efficiency, and low maintenance requirements.
Dr Ghatnekar elucidates a cost-effective technology, ¨Vermi micro bio-filter- a kind of trickling filter, is a four-stage technology that comprises four tanks. The lower layer is filled with rubble stones, the next with bricks, followed by sand and a layer of charcoal, with a bedding made of specific micro-organisms and enzymes and under the root zone theory, plantations like canna and banana- a combination of micro-organisms, enzymes, root zone, and earthworms.¨ The treated water can be used for a number of non-potable purposes by industry as well as households. This not only reduces dependency on freshwater, but also keeps water pollution in check. ¨If the initial pollution level is 100,000 ppm (parts per million) COD (Chemical Oxygen Demand), the last level would be 200 ppm COD. To treat about 22,000 litres of effluent per day, a one-time investment of 10-12 lakh would suffice,¨ he adds.
Wastewater management mechanisms will thrive only when there is reformation in terms of perspective. The terminology ´waste´ needs to undergo a change- even used water is a valuable resource that has the potential of being recycled and reused.
CATEGORIES OF WASTEWATER
NATIONAL STATUS OF WASTEWATER GENERATION AND TREATMENT
The total wastewater generated by the 299 class I cities is 16,662 Mld approximately 81% of the water supplied. The state of Maharashtra alone contributes about 23%, while Ganga river basin contributes about 31% of the waste generated. Only 74% of the total wastewater generated is collected. Out of 299 class I cities 160 cities have sewerage coverage for more than 75% of the population and 92 cities have between 50 and 75% of population coverage. On the whole 70% of the population of class I cities are provided with sewerage facility. The type of sewerage system is either open or closed or piped. As per the latest estimate out of 22,900 Mld of wastewater generated, only about 5900 Mld (26%) is treated before letting out, the rest i.e., 17000 Mld is disposed of untreated. Twenty-seven cities have only primary treatment facilities and forty-nine have primary and secondary treatment facilities. The level of treatment available in cities with existing treatment plant varies from 2.5% to 89% of the sewage generated.
¨80 per cent of the sewage is released untreated¨
Ravi Budhiraja, Chairman, Maharashtra Water Resources and Regulatory Authority (MWRRA)
The world´s fresh water resources are being squeezed. We are facing an enormous challenge of providing enough water for food production, domestic use, power generation, industrial uses, and environment protection. Demand for water is slated to increase by 55 per cent globally.
Currently, India is using 4500 billion cubic metre of water per year. By 2030, it will go up by more than 50 per cent to 6900 billion cubic metre per year. As we urbanise, we require more and more water. The current urban population in India is around 3.84 billion as opposed to 3.45 billion rural population. During the period 2010-15, on an average, around 200,000 people have been moving to the cities daily, and every second the urban population is growing by two persons. By 2030, the numbers would stand at 4.97 billion urban population against 3.35 billion rural. More than 75 per cent of the country is experiencing a serious lack of water security. Water security is the capacity of the population to safeguard sustainable excess- adequate quantities of acceptable quality water for sustaining livelihood, for individual and socio-economic well-being, and for preserving eco-systems in times of peace and political stability.
There are five aspects of water security, namely, household water security, urban water security, environmental water security, economic water security, and water-related disasters. Societies can enjoy water security only if they successfully manage their water resources and services as well as ensure effective waste water management.
There is no proper assessment today of waste water generated and treated. Most cities do not have adequate sewage treatment facilities, or the infrastructure for sewage treatment. 80 per cent of the sewage is released untreated into water bodies.
Wherever possible, decentralised waste water treatment policy needs to be adopted. One of the desired beneficial options for the use of treated wastewater is for irrigation, thermal power plants, and secondary domestic purposes. Installation of dual pipelines is a priority, so that treated water can be used for gardening and other purposes.