With rising urbanization and industrialization, growing population and improving standard of living, water demand and consumption is increasing at a rapid rate. To add to it, the fresh water supplies are themselves limited by the nature and at the same time, drought, depleting water table and aquifers, deforestation, climate change and pollution have disturbed the availability patterns of potable water.

Many developing countries struggle to provide safe and sufficient drinking water and proper sewage system. Water scarcity, which plagues 1.1 billion1 people presently, will be a bigger threat than the financial crisis. Over the next 40 years, world's population will increase from 6.7 billion to an estimated 9.7 billion2 with most of the growth happening in developing countries, which are already suffering high water stress. As far as India is concerned, we are, currently, in a comfortable position with enough water to provide each citizen over 1820 m3/year.

But, this will soon become an issue of concern, as it is estimated that each individual needs 1,700 m3 to cover drinking, hygiene and food requirements and the availability is expected to drop to 1,140 m3 by 2050. All these facts and figures might sound scary but the truth remains, water demand is far outstripping the number of people using it.

There is no denying the fact that people are gradually realizing the importance of water conservation, efficiency, and reuse. Building sector, in particular, which incidentally consumes 12 per cent of potable water supplies has come to understand the opportunity that these shortages present. It is a ripe area for innovations to overcome the consequences of water scarcity.

Wastewater management, specifically, presents a huge potential apart from water-saving technologies like rainwater harvesting, drip irrigation, and other conservation methods, and it is still untapped. Reuse of wastewater through treatment yields major results, economically and in small-time frame.

Wastewater in commercial buildings, essentially, can be of two types - grey water and black water. Grey water is the wastewater from bathroom/toilet fixtures (such as basins, showers, and baths), laundry fixtures (such as clothes washing machines and laundry troughs) and kitchen facilities (such as sinks and dishwashing machines). Depending on the level of wastewater treatment, grey water can be recovered and used for applications such as toilet flushing and irrigation. Black water refers to 'waste discharges from the human body' which are collected through fixtures such as toilets, urinals, etc. While it is possible to use this wastewater for drinking purposes once treated and disinfected as in Singapore and sold as 'New Water', it is generally used for non drinking use.

 Wastewater Reuse Possibilities

In-Facility Use - Toilet and Urinal Flushing

The reclaimed water produced from infacility treatment systems can be used for toilet and urinal flushing purpose in facility. The buildings have to be equipped with dual pipeline system: one line for hand basin wastewater and another for toilet and urinal wastewater. The collected hand basin wastewater has to be connected to the treatment system that is usually located at the base of the building.

Landscape Irrigation and Roof Gardens

Treated wastewater and, primarily, domestic treated sewage can be reused for watering plants. At Paharpur Business Centre & Software Technology Incubator Park (PBC), soapfree water is reused for gardening. PBC realized that, approximately, 150 litres of soap free waste water every day was going into the drains and decided to reuse the wastewater by channeling the flow to the garden for irrigation purpose. This not only helped them in saving water, but also saving electricity as they do not pump water for gardening purpose.

Another important concept is roof gardens. Roof gardens or green roofs in commercial buildings can play a part not only in water and wastewater management, but also in improving the energy performance of the building by keeping the inside of building cool. In a commercial building, roof gardens can be used either for storm water retention or to evapotranspirate the effluent generated from wastewater treatment plants.

Ornamental

This wastewater reuse can be aesthetic such as decorative pools, decorative fountains, ponds, etc. However, since the reclaimed water in decorative fountains has a greater possibility of human contact, the highest quality of reclaimed water is required.

Fire Protection

Reclaimed water can be used for fire fighting and protection. It can be used for fire protection in hydrants or in sprinkler systems in commercial facilities.

Advantages

The benefits of implementing wastewater management initiatives in buildings may include:

Of course, all these technologies /systems come with a price tag and entail initial substantial investments but keeping in mind their costeffectiveness, builders are sure to reap phenomenal benefits in the long run in the form of reduced operational costs and enhanced ROIs. Water prices will continue to increase sharply with reduced availability. It is best for builders to future proof their developments by having zero discharge from their developments of water.

For your valuable suggestions to conserve water, log on to www.greenspaces.in / ideas and post your bright idea there on the website for others to benefit from it.