Nature-based solutions as enablers of circularity in improving water quality
With the pace and scale of development and urbanisation in India, its water bodies have been getting toxic. Almost 70% of surface water in India is unfit for consumption and every day almost 40 million litres of wastewater enters rivers and other water bodies with only a small fraction adequately treated. A recent World Bank report suggests that such a release of pollution upstream lowers economic growth in downstream areas, reducing GDP growth in these regions by up to a third. Additionally, it is imperative that measures to treat contaminated water do not themselves add a huge carbon footprint on the environment exacerbating climate change impact. Nature-based solutions (NBS) which are inspired and supported by nature and use, or mimic, natural processes to contribute to the improved management of water are environmentally sensitive solutions that can work either through use of green infrastructure to treat water or as a hybrid solution with grey infrastructure. NBS show particular promise in achieving progress towards achieving the 2030 Agenda for Sustainable Development through a focus on sustainable food production, improved human settlements, access to water supply and sanitation services, and water-related disaster risk reduction. They can also help to respond to the impacts of climate change on water resources. A key feature of NBS is that they tend to solve multiple problems at once in the ecosystem. In the context of water, NBS provide multiple water-related benefits and also help address water quantity, quality and risks simultaneously. The following are a few examples that showcase how designing solutions with nature for improving and managing water quality in India can be implemented. 1. Floating Islands Floating Islands are constructed floating treatment ecosystems that mimic nature’s process and provide a wetland effect to water-bodies to clean the water. They provide habitat to organisms such as invertebrates, insects, fishes, birds, etc. to restore the ecological cycle and have multiple benefits. Salient Features: Sustainable Solutions: It serves as a sustainable habitat providing valuable surface area for micro-organisms which are a critical part of the ecosystem. Improve Water Quality: Removes pollutants and recycles nutrients from water by acting as natural bio-reactors. Habitat Enhancement: Improves habitat above and below the waterline along with creating habitat for all lifeforms Increase Beneficial Bacteria: The islands provide bacterial support necessary for the treatment and improvement of water quality. Prevents Algal Blooms: Floating Islands reduce the formation of algae and other invasive floating species. Reducing Evaporation: The islands cover a certain percentage of the water-body to reduce evaporation. Increase Fishing Conditions: The marine grade material is safe and non-toxic to fish and other species and can be used commercially to rear fish. Improve Landscape: The growth of different plants on floating islands forms a favourable and aesthetically pleasing landscape. Application: Habitat Management River and Lake Restoration Water Quality Storm Water Treatment Coastal Protection Aquaponics and Gardening Floating Islands have been implemented at many lakes across India. Bangalore is the leading city in India in terms of implementation, having installed it at Hebbagodi Lake, Puttenhalli Lake, Mahadevpura Lake among others. The largest Artificial Floating Wetlands in India are at Neknampur Lake in Hyderabad. NEERI (National Environmental Engineering & Research Institute) Nagpur has installed floating islands at multiple lakes in Mumbai and Thane for testing purposes. Hauz Khas lake in Delhi also has a few floating islands installed in it. Clean-Water based out of Indore has the best floating islands in terms of island quality and treatment efficiency and they have installed this at multiple lakes in Indore such as Police Training College, Musakhedi, Bicholi Mardana Lake and Harsola Lake. 2. Green Bridge Technology The Green Bridge Technology approach was developed by Shristi Eco Research Institute (SERI), Pune. It uses filtration and purification power of biologically originated cellulosic or fibrous materials in combination with the root system of plants, sand and gravel. It involves building alternate inverted-V shaped stone structures across the given length of a river. This inverted V is covered with a woven structure made of coconut coir or dried water hyacinth or aquatic grasses and a mix of microbes and the bio-chemical solution is then poured into it and covered again with coconut coir. The water flowing through these structures carries the solution down the river cleaning up all heavy metals deposit in it. Planting of shrubs and grass helps in absorption of soluble substances, including heavy metals and helps in regeneration of aquatic life. Salient Features: Designed specifically depending upon the conditions and flow of the wastewater to the rivers or lakes. The length of the bridge varies with the site specifications. Suitable for in situ treatment in rivers, flowing streams. No skilled labour is required for its operation and maintenance Application: The installation of Green Bridge was done at one end of Ahar river, the point where the river enters the Udaisagar Lake. Six bridges of varying length from 12 to 14 metre were installed. Having a trapezoidal shape, the three limbs have a loose stone wall of 4-metre width at the base and two-metre at the top. Two screens made up of mild steel with anti-corrosive paint were installed to prevent floating objects. All floatable and suspended solids like cans, bottles and other wastes were trapped in this biological bridge. Plants have had a very effective role in eco-restoration work. Lemongrass, barley grass and a small variety of bamboo were used. In addition, local shrubs like Guggal (Commifora wightee), Kanna jhadi (ephedra) and trees like drum stick, peepal, tamarind, amaltas (cassia) and Arandi (castor) were also planted for their anti-bacterial and anti-turbidity properties. Once the water hyacinth and floating materials like plastic were removed, sun rays and air could penetrate the water surface. Thanks to the bio-culture of green bridges, the muck deposited at the bottom of the river started releasing gases like methane and carbon dioxide. The muck, totally devoid of oxygen initially, became oxygenated and erupted on the surface. Within two months, the dissolved oxygen rose from nil to 6.9ppm resulting in a return of aquatic life. The acidity level decreased from ph level 10 to 8 and faecal coliforms decreased by more than 80%. Now animals can be seen drinking water from the canal and birds feeding on fish and other organisms. Farmers are happy that their water is not toxic anymore and there is no foam coming out while pumping out water. This project was carried out by Jheel Samrakshan Samiti (Lake Conservation Society), a people’s organization, who implemented this technology with labour support from affected village communities, collaboration with International Lake Environment Committee Foundation, Japan, and active participation of all stakeholders-Udaipur Chamber of Commerce & Industry, civil society groups, village councils, industrial organizations and government agencies in 2009. 3. Ecosolus Bacterial Products Ecosolus has a range of 100% environmentally responsible bacterial treatments (aerobic) for all forms of organic waste. Our products are based on naturally occurring bacteria that will effectively digest the effluent in-situ without using any pathogens, chemicals, biocides, bleaches, nor synthetic enzymes and there is no requirement for PPE or COSHH. By identifying and selecting the appropriate bacillus and blending them into an optimized consortium, the bacteria can be used to digest vast quantities of organic waste, toxins, fats, oils, grease etc. in wastewater in situ, i.e. no need for transport, thus reducing the carbon footprint of vehicles being used. By adding oxygenation agents and initial nutrients, the desiccated bacterium can establish quickly to germinate and colonize. When this has occurred, the bacterium will seek a food source to survive and multiply. The bacterium will also augment natural bacteria within the water and will replace pathogens with probiotics, i.e. ‘good bacteria’. In simple terms, the Ecosolus product requires limited assets to distribute or dose and limited resources required to manage. Application: Industrial Waste Water Treatment Lakes, Rivers, lagoon and Ponds wastewater treatment Drains and Sewage System treatment Hydrocarbon & OWI treatment Fat, Oil and Grease (FOG) treatment Uric Acid elimination 4. The Water Recovery System by Absolute Water Pvt. Ltd. Absolute Water Pvt. Ltd has developed an eco-friendly wastewater management technology, that converts sewage water into clean, potable water. It could be the solution to water-stressed cities. The Water Recovery System is a non-chemical, non-R.O. System with very high recovery (greater than 85 per cent) of water. Contaminants along with harmful bacteria, virus and other pathogens are filtered by the specially designed membrane without any sludge generation. The feed is taken from the bio-filter based treated sewage tank or any source of water as an input of The Membrane Filter. The water is made to pass through a pressure sand filter to remove any suspended solids. Another filter ensures that the feed to the membrane does not have any particles in it, ensuring the long life of the membranes. The filtered water from the membrane is potable/contact water/bathing water quality and the reject is further discharged, which is highly rich in nutrients and has a BOD > 10. Salient Features: India’s first 100% green water recovery plant. Converts domestic raw sewage water into drinking water quality as per WHO standards. No odour, and non-RO technology. Non-chemical and special membrane system. Minimal power consumption and can work on solar as well. No sludge generation as compared to other conventional systems. Least operation and maintenance cost in comparison to conventional systems. Modular/civil units as per space availability and requirement Application: 100 KLD Water Recovery System at Delhi Jal Board, Kesopur, Delhi Inlet source of water – Domestic raw sewage Area Required – 130 sq. meter Power Consumption – 2.5 Kw/Hr Operational Since – 1st August 2015 Plant capacity – 100 KLD per day. Organic Manure Generation – 7 ton per year. Use of treated water For domestic use in Delhi Jal Board Colony at Keshopur For cleaning DTC buses 5. ECOSTP ECOSTP is a nature-inspired solution as opposed to the conventional motor-based STP with energy-hogging motors, exhaust fans, pumps and blowers. ECOSTP treats sewage in a decentralised, self-sustainable way in underground chambers through biological means without using any power or need for any human intervention. It utilises functional principles and strategies of microorganisms and ecosystem as found in a cow’s stomach. Similar to how the ruminant stomach in a cow turns grass into milk, ‘bad’ water is converted to ‘good’ (non-potable) water mimicking the digestion process of the animal. Salient Features: Decentralised No power needed No use of chemicals Self-sustainable Low maintenance Ninety per cent cost-effective as compared to the conventional STP Ecological No need for dedicated operators or human intervention Waste between 5KLD to 1MLD can be treated using ECOSTP. Requires double space in comparison to conventional STP’s Can be built-in setback area or under the ground Process: The design of ECOSTP is a combination of intelligent deployment of anaerobic bacteria(natural digestor) and wall structures of the treatment plant similar to the chambers in a cow’s stomach. The first chamber is the primary sedimentation chamber where the sewage enters. The sludge settles at the bottom because of gravity and water flows to the second chamber through a series of baffle pipes. The second chamber is an arrangement of multiple mini chambers, where water is made to flow through upflow baffle reactor filters with anaerobic bacteria(made from cow dung) which feeds on all the contamination. In the third chamber (Rumen digestor), the water passes through multiple filter mass and goes to the fourth chamber. In the last stage, water is passed through a horizontal wetland with vascular plants and algal colonies which remove pathogens and nutrients(nitrogen and phosphorous) from water. The end result is that the sewage is converted into clean non-potable water, gas, and very little sludge (digester). Application: ECOSTP has been used as an alternative to conventional STP in various residences, housing societies and commercial buildings. About the Author Kanchan Joneja (LinkedIn) is an architect, design researcher and development professional who is constantly experimenting with a design for positive social and environmental impact in both urban and rural areas. She has experience working with SEEDS on projects that strive to reduce risk from disasters by building back better and developing resilience in communities through decentralised solutions across India. She has also worked within the domain of sustainable construction practices and affordable housing. She holds an undergraduate degree in Architecture from the School of Planning and Architecture, New Delhi. Sukriti Thukral (LinkedIn) is an architect and researcher with a deep interest in urban systems, affordable housing and conservation of natural and built heritage. She has been working on architectural projects with the belief that we need to build less and build smart, always being conscious of the natural resources we use. She is known to have a keen eye for observation of patterns in the environment and human behaviour. She is an alumnus of the School of Planning and Architecture, New Delhi with an undergraduate degree in Architecture.