By Sabarna Roy, Senior Vice-President, Business Development, Applications Technology, Engineering and Strategy Department, Electrosteel Group, Kolkata
Water demand is increasing at an alarming rate, so breakthrough technologies is required to ensure sustainability and change prevailing practices. The driving forces for changing the prevailing practices include changing demographics, the evolving economic and societal situation, and the shift from the collective to the individual. Efficiency and adaptability are required to pave the way for restoring and improving urban infrastructure and providing access to clean water. Smart water reclamation and reuse are some key solutions to counter the water scarcity problem in the world.
Water reuse technologies
Water reuse and its use in non-potable applications can only be achieved through advanced technologies such as membrane technology and advanced oxidation. The advanced water treatment systems for water reclamation include:
Preliminary treatment
- To remove floating and suspended solids matter
Advanced treatment
- Reverse osmosis
- Electrodialysis
- Nanofiltration
- Ion exchange
- Advanced adsorption systems (AC or modified clay)
- Combinatory oxidation and filtration system(s)
Advanced oxidation processes
- Ozone, ozone/hydrogen peroxide, ozone/bio-filtration
- UV/Chlorine, UV/hydrogen peroxide
The problems associated with advanced water treatment technologies are operational cost, sustainability and general feasibility. Nevertheless, technology transfer at the global level should be undertaken for advancements in breakthrough technologies for water reuse.
Water reuse policies in India
The consequences of pollution due to wastewater and degradation of water sources pose a big challenge. The natural process of water purification in rivers and waterbodies suffers from inadequacy, and stream sanitation as a natural process has failed due to pollution load. The policies introduced by the government for water reclamation are:
Rajasthan: TWWR Policy, 2016 – The policy lays down the guidelines for achieving 100 per cent sanitation, using wastewater as a resource and using treated wastewater for agriculture and industries with due safeguards.
Maharashtra: TWWR by Power Plants and Industrial Estates, November 2017 – Under this, the Maharashtra government stated that thermal power plants and industries under the Maharashtra Industrial Development Corporation will not get fresh water after three years. To achieve the policy objectives and goals, a time-bound schedule has been laid down.
Gujarat: TWWR Policy, 2018 – The Gujarat government aims to maximise the collection and treatment of sewage, and reuse the same on a sustainable basis to reduce the stress on freshwater sources. The policy considers wastewater as an economic resource. A time-bound schedule for full use of reclaimed water by 2030 has been proposed under the policy.
Conclusion
Considering all our traditional water sources, existing wastewater treatment plants (WWTPs) constitute captive and available water sources for treatment and reuse. The reuse of all treated wastewater to meet all human needs is imminent. The treatment plants must be redesignated as secondary water sources and termed reclamation plants. A recycling market can be created by working with various stakeholders (and possible consumers) such as institutions, commercial establishments, industrial clusters, railways and metro boards, port trusts, the construction sector and premium consumers. The Ministry of Jal Shakti and water regulators should give guidelines to rename all sewage treatment plants/ WWTPs as SRPs/WWRPs while providing a conducive framework for reuse of treated wastewater.