The Times of India            06.05.2013 

Grey water treatment can help reuse 60% used water

Grey water, which comes out of kitchen sinks, showers and washing machines, can be filtered and stored for non-potable uses. For a city grappling with uneven water distribution, recycling grey water can be a workable solution. Nearly 60% of the used water can be safely reused by the same homes and industries for watering the garden, flushing and even car and floor washing, said experts. It would conserve the filtered and treated water supplied by the Pune Municipal Corporation and ensure more equitable supply, they added.

Of the 700 million litres water supplied by the civic body every day, more than half is used for purposes other than drinking, and eventually flows down the drain to mix with sewage (black water). A little initial investment can help recover 90% of used water which can be recycled to meet more than 75% of our daily water needs, conservationists said.

Sandeep Joshi, environment technologist and founder of Shrishti Eco-Research Institute (SERI), said it is a simple way of reducing water bills and helping the environment. "Any water which is free of faecal content can and should be reused," he said. The institute is working towards a cleaner environment with the help of natural technologies to treat waste.

According to Joshi, installing a grey-water treatment system requires two tanks, one to store the grey and the other to treat it, and a small filter for the treatment. "Since you are not treating the water to make it fit for drinking, the investment is not heavy, yet it proves cost-effective in the long run," he added.

Harish Joshi, managing director or a Pune-based packaging solutions company, installed such a system in 2007 in his factory to recycle close to 3,000 litres of water coming out of the bathrooms and kitchen every day. He has recommended it to all the small and mid-sized plants.

"What was appealing was that there is hardly any recurring cost or operational expenses. It does not require electricity. It has helped plants grow which add to the aesthetics of my factory. We save money since we do not have to call for water tankers," he said. Joshi also propagates the idea among those he knows in the industrial sector.

The idea is also making some headway with the Pune Municipal Corporation. Plans are to introduce grey water recycling system in old and new constructions across the city. Work on appointment of consultants and setting up of pilot projects in the detailed project report (DPR) are on.

The proposal suggesting recycling of grey water was approved by the general body (GB) when it okayed the development plan (DP) for old city areas a few months ago. "Appointment of consultants has already begun. We can hope for some pilot projects by June," said Congress corporator Aba Bagul, who had first proposed grey water recycling in the DP.

The basic data about grey water system is ready. The civic body has divided the city into 23 basins to lay and connect storm-water pipelines which are used only in the monsoon and otherwise remain dry and are connected to the nearest river or nullah.

"The PMC should lay separate pipelines in housing societies to collect grey water and connect these lines to storm-water drains. This water should be treated and released in the river or canal for irrigation purpose. The treatment will not cost much as compared to the sewage treatment and agriculture will get good quality water," states the proposal approved by the general body.

"The city must start using grey water. More awareness campaigns will help spread the word," Bagul added. According to him, the civic body should make it mandatory for new constructions to have a separate system to collect grey water.

Experts said it is more feasible to introduce a system for collecting and treating grey water for reuse during the design phase itself. Suneel Joshi, state head of Jal Biradri, said people do not understand the value of clean water.

"In our country, water is worshipped as god. People in the city must be sensitive about it, rather than follow a use-and-throw policy. Pune has reservoirs, but the problem of unequal distribution of water remains. The civic body has not popularised it, nor have the architects thought of incorporating it in their designs," he said.

The New Indian Express                 27.04.2013

Pistia Stratiotes could easily absorb copper, lead and cadmium from the surrounding water. | EPS

Can you imagine clearing up polluted water bodies with aquatic plants? Soon, it might be a reality as scientists of the University College in the city have found plants that have the capability to absorb heavy metals from water bodies and render them harmless.

With their focus back on nature now, many science labs had been looking around for organisms, from bacteria to plants, that can absorb the pollutants flushed into the environment, be it water or land. But even microbes were often found to be at a loss on how to deal with heavy metals such as cadmium and lead. That is when the research teams turned to plants.

Among the many such research groups in the city focusing on this area, the one at the Department of Botany, University College, has managed to zero in on several plants that have the ability to remove toxic substances from soil and water and thus detoxify them, in a process scientifically known as ‘phytoremediation.’

The University College group comprising Princymol Stephen, Devi Chinmayee M, Mary Sheeba A, Swapna T S and Mini I  recently found that the aquatic plant ‘Pistia stratiotes’ not only has a high tolerance level for toxic heavy metals but that it can also be used quite effectively in phytoremediation.

The little pond inside the University College was where Pistia was grown. It was later exposed to heavy metal-contaminated water in the lab for as long as ten whole days, after which the researchers analysed the enzymes of the plant to see how well it tolerated the stress.

 ’Only stress-tolerant plants can be effective in dealing with the heavy metals. We found the antioxidant defence mechanism in Pistia to be quite good,’’ said Swapna, who along with Mini, leads the phytoremediation studies at the Botany Department.

They found that Pistia could easily absorb copper, lead and cadmium from the surrounding water. ‘’It either nullifies these toxins or keeps them away in small bag-like structures called vacuoles, where they are rendered harmless. When the plant dies, some of the metals may return to the environment. Complete detoxification happens rarely, but we can bring down the levels of pollution,’’ said Swapna.

The other side of the story is that some of the commonly used leafy vegetables may have this accumulative bioremediation properties and that would be bad news for those who consume these vegetables regularly. A wild relative of our ‘Cheera’, the ‘mullan cheera’, was found to have a very high bioconcentration factor and it accumulates copper and lead much above the toxic limits.

‘’So, if you are consuming ‘mullan cheera’, you really need to know where it comes from. If coming from polluted sites, it may be harmful since the plant accumulates and translocates metals to the leaves,’’ said Swapna.

Since the ‘mullan cheera’ showed such high values for bioaccumulation, the research group is also studying the common green ‘cheera’, scientifically known as Amaranthus viridis. The group is also studying several aquatic plants such as Lemma, Spirodela, Hydrilla and Salvinia if they can clear up toxic matter from water bodies.

 Perhaps, our water bodies are already heaving a sigh of relief.