Dear Panditji,

What is meant by Dry composting toilet? How does it work? How are the separated excretes, urine and faeces disposed? What happens to ablution water? Can this system be used in metro areas?

Dr. Girish Udapudi,
Jamkhandi, Karnataka

Dear Girishji,

Dry composting toilets are ecologically sound methods of sanitation. It minimises water use, recycles nutrients from human excreta and prevents water pollution. Ecological sanitation can save upto 25-30 per cent of household water consumption. In most ecological sanitations, the urine and the faecal matter are diverted at the source and treated separately.

Separating at the source helps in recycling wastewater efficiently. The faecal matter is used for improving soil conditions. The urine is used as a liquid fertiliser, which can be connected to a plant bed or a field. Using blackwater (a mixture of faeces and urine) as a fertiliser can be best achieved by blending in organic household waste or farm manure and composting.

Paul Calvert of ‘Ecosolutions’ has designed a compact system, to suit urban as well as rural locales. To know more on ecological sanitation, and contact experts who could guide you, visit the following websites:

www.eco-solutions.org
www.ecosanres.org
www.ecosan.org and
www.wastewater.net

Dear Panditji

I find that the water in my area is hard. Can you tell me methods to decrease the hardness?

Nitin Raut,
Via e-mail

Dear Nitin,

There are simple home-made methods to soften or reduce the hardness in water. The hardness in water is caused by a high content of minerals or metal ions, mainly calcium and magnesium in the form of carbonates and sulphates.

To remove the hardness, the ions are exchanged for sodium or potassium ions. Temporary hardness, caused by carbonate ions, can be removed by boiling. In the process, a scale forms on the inside of the vessel. This is made of insoluble calcium carbonate.

The most economical way to soften household water is with an ion exchange water softner, by using sodium chloride or common salt. The principle is the same, where the ions of hardnesscausing minerals are exchanged for sodium.

The hardwater passes through an ion exchange resin made of beads (artificial or natural zeolites). Ion exchange resins do not remove chlorine or organic contaminants in water. This is done by using charcoal, usually not done in homes.

Dear Panditji,

I was quite excited to read your story on urban birds. I have lived in Bangalore on and off for most of my life. The common saprrow was one bird which was in abundance in eariler years. Today, I cannot see a single sparrow. What could be the reason? What have we done to make this bird disappear?

What can we do to get it back? Sometimes I travel to smaller towns in Punjab and am delighted to see hundreds of sparrows there...The only birds I now see in Bangalore are the crows and in the mango season, the koels and parrots.

Vasant Cavale,
Via E-mail

   
Dear Panditji,

While I appreciate the red alarm that your story on ‘Missing Birds’ strikes for the dwindling number of birds, I have to make a few remarks about the contents. I may sound a bit blunt, for which I seek your pardon beforehand. The article is not restricted to the city birds, which are normally dependant on human settlements. So I consider sparrows, crows and pigeons only as the city birds.

Your article rightly brings out the survival of crows due to their adaptability to changing circumstances. But the dwindling number of sparrows is attributed to ‘infant mortality’ due to starvation on account of their not being fed the soft worms and caterpillars, which are killed by the use of pesticides.

Sure it is a nice way to get rid of these pests, but do the birds eat all the worms to the extent required by a farmer to save his crop? If not, can he reserve a plot of his farm untreated for the birds to take care and feed their young ones? Similarly Smt.

Lalitha Vijayan’s explanation that urban people spraying their gardens with pesticides; the pesticides finding their way to the water bodies; and city birds drinking this polluted water and dying, seems more academical than real. In my rosiest dreams, I cannot see people in a city having their gardens, watering them, using pesticides etc.

Long ago, perhaps in Science Today, I had read an article on the life cycle of sparrows. It was stated that the sparrows are the timidest birds and abandon their food at the slightest distrubance. This poor eating habit causes tuberculosis, which was the main reason for their death.

The article was based on a large number of autopsies on the dead sparrows. Also, the death due to predators is a natural occurrence and not specific to cities. I had come across the debate of use of natural predators to control pests, before I retired from Horticulture Department.

The entomological studies have shown that the breeding rate of the pests far exceeds that of the predators, which is perfectly in keeping with the Nature’s Laws. So the argument of the reign of natural predators against pests remains more theoretical than practical.

S M Chandawarkar
Via E-mail

Dear Panditji,

I have gone through the last edition of GT and it was very informative. There is no doubt that birds are disappearing in urban areas, but these are also dwindling in rural areas too, due to changing socio-climatic structure. Felling of trees and use of agro-chemicals may be one important reason.

Many of these birds are bioindicators of environmental health and their very sight generates in us a feeling of happiness to our life. As such their survival is essential as that of ours. My team is working on safety issue of Diclofenac in vultures in association with BNHS. I feel we must also emphasise on our ancient ways to conserve biodiversity and environment. Congratulations for the good work being done by DTE and GT.

Dr D Swarup
Head, Division of Medicine and
Incharge, Centre for Wildlife, IVRI,
Izatnagar

Dear Panditji,

There is something I feel very strongly about. Can’t we get our children to start a campaign to force battery manufacturers (big, small, cell) to create a countrywide facility to take back used batteries? Something as simple as a collection box for used batteries in every shop that sells new batteries, and maybe a nominal return price to encourage returns.

It really worries me to see the way we consume and discard batteries without a thought. Perhaps we could get children passionate about the safe disposal of dead batteries? It’s their world that we’re polluting. Long may you continue your good work.

Shyamala K Das
Via E-mail