Organochlorine residuals in groundwater of Pondicherry region.

Nineteen representative water samples were collected from surface and ground water sources, covering urban, rural area, shallow and deep aquifers in Pondicherry region. The samples were analysed for various pesticide residues such as HCH, Aldrin and DDT. Both surface and ground water sources found to exhibit the residuals of various pesticides. The residual levels oforganochlorine pesticides were found to be three to four times more in ground water sources of agricultural areas than in urban areas, indicating the impact of usage of pesticides for agriculture. It is evident that total residuals of organochlorine pesticides are more in tanks followed by shallow wells and deep wells. However, the residual levels of pesticides were found well below the maximum acceptable level of 100 ng/L for individual pesticides for drinking purpose in the study area. Though the residual levels of pesticides in the study area were well below the acute toxicological problems, the major concern is for long term, chronic exposure from compounds that may be carcinogenic.

Nutrient concentration in groundwater of Pondicherry region.

The surface and groundwater samples were collected from urban, rural areas, shallow and deep aquifers in Pondicherry region. The samples were analysed for various nutrients such as Nitrate Nitrogen, Nitrite Nitrogen, Ammonia Nitrogen, Phosphate and Dissolved silica.The elevated concentrations often fold increase against a background concentration of less than 2 mg/L of nitrates was observed in the study area. The maximum nitrate concentration (22 mg/L) in water is well within the limits of 45 mg/L prescribed by World Health Organization. The nutrients were observed about 2 to 3 times higher in groundwater of urban areas than in rural areas, indicating abundant leaching of nutrients from municipal waste and sewage effluent. The nutrients displayed a trend of higher concentration in shallow groundwater and lower in the water in deep aquifer and tank water. The higher concentrations of dissolved silica (13 mg/L to 100 mg/L) against an average concentration of 5 mg/L in the ground water of unreactive aquifers shows the presence of amorphous silica in the subsurface formations, slightly acidic to neutral nature of water in aquifers and also interaction between formation material and water.

Anaerobic sustainability for integrated biomethanation of sugar mill waste and municipal sewage.

The study investigates the viability of biogas generation by integrating the biodegradable waste product of sugar industry viz., pressmud with municipal sewage using biomethanation process. The total solid content of pressmud and sewage mixture was optimized with respect to maximization of biogas yield with continuous monitoring over several operating parameters. Optimum total solid content of 5% found to yield 80 m3 of biogas per ton of pressmud compared to 65m3 per ton of conventional digestion of pressmud alone. It is estimated that 3.4 x 10(8) m3 of biogas can be generated through integrated biomethanation from the potential of4.2 million tons ofpressmud available annually in India.