All in a day's work

All in a day's work

Hotel Grand Hyatt, spread over four hectares of water-starved Vasant Kunj, has devised a proactive method of meeting its mammoth demand for water: it is the only five star hotel in the capital to completely recycle its sewage. "This is an extremely rocky area. Moreover, we are not connected to the Municipal Corporation of Delhi water supply. We are, therefore, very conscious of the need to conserve water," says David Pacey, manager of the hotel.

At first, the hotel depended on its four tubewells. However, that water just did not suffice for its colossal daily consumption -- 1,872 cubic metres. "We purchase over 500 litres of distilled water everyday for drinking purpose. But for non-potable use, it was impossible to purchase the quantity of water we required, and the bore wells were not enough," explains Pacey.

According to Central Pollution Control Board (cpcb) guidelines, all commercial establishments are required to treat their sewage and wastewater to a high degree of purity before they are released. In this scenario, combined with the water crunch that the hotel faced, recycling treated sewage for non-potable use was the best bet.

Grand Hyatt's water consumption pattern is as follows: Domestic use (including toilet, kitchen and laundry accounts for 51 per cent of the water consumed; this water moves into the sewerage system. About 44 per cent of the water is used in air conditioning and cooling towers; this water largely evaporates. Five per cent of the water is used in the gardens; this percolates into the ground. It was, therefore, the domestic wastewater that could be recovered for recycling.

Finding a site where the Rs 40 lakh treatment plant could be installed was not easy because of the rock bed the hotel sits on. After due consultations with architects and project managers, a site in the northeast corner was selected. When planning the drainage system, pipes carrying waste from kitchen, laundry and bathrooms were segregated, as they needed to be treated differently.

The kitchen waste connects to a grease-trap, which removes grease periodically. "Every week, the grease is taken out of the traps manually, and disposed along with the hotel garbage," says O M Manohar, director of engineering in Grand Hyatt. The grease-free effluent is then connected to a collection-cum-equalisation tank of the sewage treatment plant (stp) for complete treatment. The laundry waste also goes to the collection-cum-equalisation tank, where it gets mixed with other sewage and kitchen waste. Although there is provision for laundry pre-treatment to remove detergents, it is not being used. "We use biodegradable detergents, which do not need treatment. They get treated with the rest of the wastewater," explains Pacey.

The combined wastewater is then introduced into the main treatment unit, where it is treated in the presence of oxygen and bacteria to remove biological oxygen consuming material (bod) and suspended solids (ss). (see flow chart: treatment process) "We follow the standards set by the cpcb, requiring the effluent bod to be less than 20 milligrams per litre (mg/l) and ss 30 mg/l," says Manohar. The hotel also checks for chemically degradable material (cod) in their quarterly inspections.

Recycling costs the hotel almost twice as much as the municipal water supply. The cost of the recycled water, factoring in cost of repair and maintenance, works out to Rs 10 per kilolitre (kl), whereas the rate of municipal water is Rs 5 per kl. Nevertheless, the manager thinks it is the best option. "We are not recycling water only because we have no option. This is the most viable way of saving water that is otherwise squandered in hotels," opines Pacey.

The Union ministry of urban affairs and poverty alleviation made wastewater recycling in all structures discharging 10,000 litres and above compulsory in July 2001. However, not surprisingly, this has not quite taken off the ground. In this context, the Grand Hyatt's initiative is an example to other institutions that have the resources, but not the will, to conserve water. 12jav.net12jav.net