Archive for May, 2011

10
May
11

Arsenic in groundwater

By Prof D Chandrasekharam Closed
Categories: Groundwater Pollution

“ Beware of arsenic in drinking water” Bombay times, 8th May 2011 is nothing new. It seem that the editor has asked his juniors to fill this space ( other wise going empty!!) with some sensitizing news and the youngster unaware of the worldly problems, filled this void with this news. Arsenic contamination in groundwater in West Bengal and Bangladesh is a global calamity! Why USA and Bangladesh, there are half dozen top Institutes in India working on this problem and suggesting remedial measures. The reporter should have called some one with this knowledge and filled this void space with better and updated news instead of publishing stale news. Some recent updates are given below for those keen in getting knowledge beyond what is casually reported in the above news paper. Let us be concerned with the state within our own country first and what ever is applicable to West Bengal is true to Bangladesh as well,  since both regions have more or less similar geological formations and both the regions are drained by the rivers originating from the Himalayas.

 Both West Bengal and Bangladesh are affected by arsenic and for over couple of decades, people in WB and BD are drinking groundwater with high arsenic levels. The permissible limit of arsenic in drinking water is prescribed by the World Health Organization is 10 to 50 µg/L. 10 µg/L being the limit for developed countries while 50 µg/L is for the developing countries. Countries like India and China were following 50 µg/L limit but recently China has reduced the limit to 10 µg/L.   Let us not debate on why some of the countries are not following 10 µg/L limit now (it is a issue related to commercial vs political lobby)

 Arsenic is a killer element. Groundwater in West Bengal and Bangladesh is contaminated with arsenic and people are drinking arsenic contaminated water for the last several decades. Since it is tasteless, millions drink such water unknowingly and succumb to its poisonous effect. Nearly 40 % of 80 million people in West Bengal are suffering from arsenic related diseases like conjunctivitis, melanosis, hyperkeratosis, and hyper pigmentation. In certain areas gangrene in the limb, malignant neoplasm and even skin cancer have also been observed. Children are the worst affected. In West Bengal, Nadia, Hoogly, 24 Parganas (N & S), Murshidabad, Burdwan and Malda are the seven districts that are worst affected. The arsenic content in groundwater in West Bengal is ~ 3200 µg/L.  According to WHO this problem in West Bengal and Bangladesh is termed as global problem and several scientific bodies are seeking solution to this problem.  Wrst Bengal and Bangladesh has now become a field laboratory with several international organizations working on this problem. A few of the organizations include: Royal Institute of Technology – KTH, Stockholm Sweden, Government of the Netherlands, Commonwealth Science Council/ Science and Technology Division, University of  Karlsruhe, Germany, UNICEF, CARE, WHO, Dainichi Consultants Japan, London Arsenic Group, University of California, Berkeley, USGS, British Geological Survey and several institutes from India.

 During eighties, to prevent cholera and typhoid menace from surface water bodies that were extensively used by the population to meet their daily needs, UNICEF advocated using groundwater. Arsenic was not detected earlier but during the course of routine quality, check arsenic was detected at levels above permissible level for drinking water. But by then it was too late and several thousands of people of earlier generation were affected. Thus by accident high levels of arsenic was detected in groundwater. Now diseases related to arsenic fom groundwater are affecting third or fourth generation in West Bengal.

 When bore well culture was introduced in West Bengal, it became shot in hand for the farmers since bore-well irrigation started giving the farmers comfortable life and they were able to rise crops through-out the year. This feel-good factor encouraged extensive bore-well irrigation and the number of bore wells increased from about 20,000 in 1976 to 5,50,000 in 2001.  Since then this number started growing beyond expectation.  Thus bore-well irrigation practice made the rural population to exploit groundwaters without any control.  Arsenic that was found only in the groundwater earlier  has now entered the food chain.

 Thus from groundwater arsenic menace has entered the food chain through irrigation practice. A large number of bore wells operate continuously pumping groundwater from different depths to rice fields. The amount of water required is quite large since 90% of the land in West Bengal is under rice cultivation.  The arsenic content in the water pumped for irrigation is same as that mentioned above ( 3200 µg/L). A recent study conducted in parts of West Bengal has revealed that paddy crop has maximum concentration of arsenic scavenged from groundwater. The arsenic content in rice grain is 0.3 mg/L, in husk it is 1 mg/L and in the steam and leaves it is > than 2 mg/L. The root accumulate large amount of arsenic. In the present study it was found to be as high as 169 mg/L. Except roots, all parts of rice plant is eaten by humans and animals. Now we are in an arsenic web!! This problem is no longer confined to West Bengal and Bangladesh. Besides rice, the vegetable cultivated through irrigation also have high levels of arsenic.  Common leafy vegetable like Red Spinach, Amaranth, Chinese Spinach, Indian Spinach have arsenic content > 0.3 mg/L. 

 Thus while countering one disease ( cholera/typhoid) the then advisors gifted West Bengal and Bangladesh with a major and irreversible catastrophe. Perhaps the wisest thing that could have been done is to boil the surface water and drink to counter cholera and typhoid.  Because of bore-well irrigation the entire aquifer (s) are contaminated.

 Remedial measures that are suggested to the rural population by the multinationals are too expensive.

 Now arsenic is also found in amount larger than 50 µg/L in all the NE states of India ( Manipur, Assam, Tripura, Arunachal Pradesh, Meghalaya and Nagaland) and it also slowly surfacing in other parts of the country.  Arsenic contaminated groundwater is reported within the Godavari sub-basins bordering Chattisgarh.  Millions of population depend on groundwater in the rural areas. Both arsenic and fluoride has become a nightmare to rural population.

08
May
11

Geothermal and Green Buildings

By Prof D Chandrasekharam Closed
Categories: Geothermal Energy

“Green Building” seams to be back in the news with a media report recently show casing a green building, eco-friendly building, that reduces coal based electric power consumption. Lower energy consumption and cost savings upto  55 % . The design of the building is based on solar water heaters, solar PV for out door lighting, water conservation methods ( wastewater treatment and recycling of water) and recharge of aquifers, lead free tiles and lead free paint, using smoke-less chullahs etc. etc. These homes are designed by eight well thought materials that is supposed to give the consumer savings upto 55 % in utility bills. However, the response to such buildings, as per the media reports, from the builders and customers seam to be poor. The reason- cost and payback period.  On the lighter side…. One can not expect urban women to use smoke less chullahs in the kitchen!!! On paper these designs look good and give very attractive numbers. But the customer and the builders know the inner details of such buildings and the cost and the demand. These data and designs are good for a research paper or an article in a design magazine,
or can be experimented with in rural and remote inaccessible areas , where lighting two bulbs itself a matter of privilege. For a more holistic view the designers and builders have to learn a lot from Chinese and the European builders where cost and energy savings that in turn reduces CO2 emission. 

A four member, upper middle class family needs minimum of 500 kWh of electric power per month to have a comfortable living. This is without the luxury of having air-conditioning, microwave and limited use of Geyser system,. This will meet the bear minimum for the family. Extending this to a housing complex with 50 apartments, the minimum electric power requirement will be of the order of 40 kWe ( assuming the electric supply is from coal based power plants). Installing solar PV system over such housing complex is feasible but the cost of unit of power will be prohibitive (~ 37 US cents). Even with subsidies, the unit cost ( ~24 US cents) can not be brought down to  single digit!! The area required to generate such power based on solar PV will be about 3000 sq.ft ( assuming a PLF of 0.18 but this is not so always and the average PLF can be about 0.08).  Of course at least 10 invertors are required. Any surge of power will trip the system. The buildings will not have air conditioning system……..that was considered a luxury a decade ago but it has become necessity now with the amount of dust particles floating in any major urban city and radiation from the buildings ( green cover is fading away!!.

 Clean Development Mechanism is an excellent instrument for India to raise above all the non-OECD countries in reducing  carbon emissions, earning carbon credits, improving the environmental and GDP growth in the next two decade provided it uses energy source mix and exploits its geothermal potential to its maximum. In order to exploit the potential barriers that obstruct the development of this energy source should be overcome and create or improve policies on sustainable renewable energies like those adopted by other countries like China. 

 According to a paper presented at the World Geothermal Congress 2010, held in Bali, geothermal energy should be integrated in the development plans, and decisions should not be taken exclusively from a purely market point of view. The national authorities will have to take advantage of the benefits of CDM and focus should be on two domestic targets: 1) Preparation of a plan for an extensive coordination of the national electricity markets and to develop regional wholesale electricity markets. This limits the negative impacts of uncertainties, both, with respect to the markets and to technological performance; 2) Internalize the social costs of the so-called negative externalities of energy production. One way to do this is to impose fine for the activities that contribute to air pollution (this is being implemented in several countries as “carbon tax). Then social advantage of “clean energy” thus becomes visible. But this is easier said than done in countries like India where the polluters are often the large industries that play an important role in the economic growth of the country as well as holding control over major policy related to energy in the country. Political will and determination to induct modern technological innovation for the socio-economic growth of the country is very essential to make countries like India to be at the top of non-OECD countries.

 Green building can be built by utilizing earth’s internal heat through geothermal heat pumps for space heating and cooling. Instead of installing solar heaters for hot waters, solar PV for lighting, using chullahs for cooking, installing biogas plants in the buildings, avoiding lead tiles and paints in the buildings, straight away 33% of electric power from coal power can be offset through geothermal. Cost is comparable to coal based electric power and urban elite can enjoy their comfort and still save carbon dioxide emissions and help the country to earn CER amounting to several millions of euros (World Geothermal Congress, 2010). Carbon trade with OECD countries can be avoided.

 GHP Systems can be bought off the shelf and there is sufficient knowledge base available in the country. Perhaps the NGO who showcased the green building should have known the existence of such systems in the world. We should provide what is feasible and adoptable easily to the consumer rather than suggesting high end solutions to the builders. Leave the wastewater treatment systems to central agencies. Maintaining such systems will add to the cost of the utility bills. When an easy alternate system that can create a green building without compromising comforts and routine is available why go for systems that needs time and energy of the urban residents during the week ends!

 Space cooling and heating on an average consumes 33 % of coal based power. Similarly additional 13% can be save from food sector (refrigeration). By adopting geothermal based green building, straight away 33% of coal based power usage can be offset thereby reducing CO2 emission by about 234 billion kg (World Geothermal Congress, 2010).