When buildings factor water scarcity

While rainwater harvesting and desilting of waterbodies have helped, the construction sector can also contribute to conservation by adopting water treatment techniques

April 12, 2024 03:15 pm | Updated April 19, 2024 03:32 pm IST

For the past couple of months, major cities in the country have been facing a severe water crisis. Water shortage in India, particularly during summer, isn’t anything new. In 2019, Chennai faced an acute water problem due to a delayed monsoon. Year after year, Mumbai goes through a predictable crisis period before and during summer. However, the alarming headlines out of Bengaluru this year have been a wake-up call to the real estate industry.

Builders and experts must therefore look at other options such as the use of smart meters, in addition to water treatment solutions, to tackle the situation.

Treated water

There are several concerns regarding freshwater being treated and reused effectively for purposes other than human consumption. How good should reused water be for construction purposes?

Anshuman Magazine, Chairman & CEO – India, South-East Asia, Middle East & Africa, CBRE, says, “Using treated water in construction is a sustainable practice that can conserve freshwater resources. However, there are potential concerns about using treated water in construction in India. Treated wastewater needs to meet specific quality standards suited for construction. Improperly treated water can contain impurities that affect the strength and durability of concrete. Moreover, treated water infrastructure in India is still developing. Treated water isn’t readily available in all regions; transporting it to construction sites has its cost and logistical challenges.”

Dominic Romell, President of CREDAI-MCHI, says, “Treated water presents a sustainable alternative. CREDAI-MCHI ensures through its developers that only after several quality tests, treated water is used in construction. It may contain chemicals that can promote corrosion in metal components used in construction. For example, chloride ions in water can accelerate the corrosion of steel reinforcement in concrete. So a lot of precautions are taken before the water is used. Real estate developers need to implement proper water treatment processes, monitor water quality regularly, and adhere to environmental regulations to ensure the safety and well-being of the environment, under-construction buildings, and people associated with the same.”

Experts say that if apartment dwellers clean the sewage treatment plant (STP) on their premises, and maintain it well, they can substantially cut the demand for freshwater and reuse the treated water for landscaping purposes.

A number of options

Conserving water by conventional methods like rainwater harvesting and installing smart meters in apartments are a step in the right direction. “But, advanced treatment process like membrane filtration, reverse osmosis and ultraviolet disinfection can purify wastewater to meet quality standards for non-potable uses like irrigation, toilet flushing, cooling systems, and construction activities. By recycling and reusing water, overall demand for freshwater can be reduced to a considerable extent,” says Romell.

He adds, “In construction practices, innovative technologies are being implemented to reduce water usage. The zero water initiative employs techniques such as using curing compounds and plasticizers to minimise water consumption during the construction process. Additionally, the adoption of Autoclaved Aerated Concrete (AAC) blocks instead of the traditional red bricks is gaining traction. AAC blocks offer significant water conservation benefits, reducing water usage by 6-10% compared to conventional red bricks. These measures collectively reflect a proactive approach toward sustainable water management within the construction industry, aligning with broader environmental conservation goals.”

Purposeful designs

Developers are also adopting various water conservation strategies in landscaping and design. They promote the use of drought-resistant plants and minimise lawns, reducing the need for more water for landscaping.

The other examples of water conserving techniques are vernacular landscaping and greywater recycling. Vernacular landscaping incorporates native plants and drought-tolerant species that require less water than exotic or water-intensive plants. Xeriscaping principles are applied to design gardens and green spaces that can thrive with minimal irrigation. This reduces outdoor water usage and maintenance costs.

Greywater recycling treats wastewater from sinks, showers, and laundry for reuse in flushing toilets or irrigating gardens. This reduces freshwater demand and wastewater discharge, promoting sustainable water use.

There are realtors who are using Internet of Things (IoT) devices to track water usage in a specific gated community or individual building. Planet Smart City, a global prop-tech company, in collaboration with Kolte-Patil developers based in Pune, has installed IoT devices in their units. Planet SIM, a smart infrastructure solution developed by Planet Smart City’s digital business vertical enables real-time monitoring and management of critical infrastructure such as light, water, air quality, and more, in residential societies.

Mukund Deogaonkar, Director, Planet Smart City, India Operations, says, “We have placed IoT devices in underground tanks as well as above-ground tanks. We measure the supply of water from underground to the top. And once we have data for a month, we figure out how much water is being utilised by a community. If we identify a deviation of 5% to 10% from the available data, then we flag it to the particular community.” In a small way we are empowering a community of 30 to 40 residents to take up the responsibility to manage water consumption, he adds.

Through Planet SIM, 1.8 billion litres of water have been saved by the installation of 751 sensors.

Bengaluru crisis

According to hydrologists Rashmi Kulranjan and Shashank Palur of WELL Labs, only one third of Bengaluru’s wastewater is redirected for external reuse. It means water is taken to Kolar, Chikkaballapur, and Devanahalli where it is used to replenish both groundwater and surface water sources. The remaining water flows into lakes and runs off land to join rivers downstream. This means the huge quantum of wastewater generated in the city is an untapped resource. Once treated to the required quality, this water can significantly mitigate freshwater consumption and can be crucial in making the city water resilient during low rainfall years. Cleaning lakes and rivers and not allowing silt to deposit in them are basics that the authorities should consider in order to avoid a water crisis. These are measures that real estate developers should also adopt.

Palur says, “The crisis is prevailing in the outskirts of Bengaluru, which grew unplanned and rapidly because of the IT boom. In the central part of the city, there is no real problem. I think the crisis is happening across cities because our development happens without a proper plan or vision. At policy level, we are working on limiting the use of freshwater wherever possible. For example, construction sites have multiple borewells.”

However, Romell suggests a workable solution. He says that the government should impose charges for water being discharged similar to levying fees for the use of freshwater. “All over the world this is being done. In fact, the taxes for water being discharged is more than for water being used. Water conservation can effectively be implemented if these changes are done.”

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