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DEPARTMENT OF ENVIRONMENTAL SCIENCES |
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3.RESEARCH 3.1.Bio-compost Composting is the process of converting all biodegradable into organic manure. In composting process certain input should be made into waste to convert the process in a short time. The major input in the compost process is microbial inoculant for composting. The microbial inoculant contains microbial consortia with different microorganism targeting different substrate. The promising microbes are Pleurotus, Trichoderma, Bacillus, Pseudomonas and Streptomyces. In the Department of Environmental Studies, microbial consortia contains several promising microns are blended in a lignite based material and being sold as biomineralizer. Application of biomineralizer to the waste material quickly accelerate the composting process. Cowdung is the other important input for composting. Cowdung is the source of nitrogen as well as microorganism.
In the biocompost process, temperature is raised upto 70.C in the initial days to kill all the pathogenic organism and weed seed. This thermophilic organism and activate the entire composting process. Maintenance of moisture by 60 % and reduce the particle size upto 2 cm are the important process in biocomposting. Turning the compost material once in 10 days will enhance the composting process. All biodegradable waste will be put into biocompost process to get good organic manure. 3.2.Vermicompost Technology Vermicompost technology is converting all biodegradable waste into nutrient rich organic manure with the help of composting earthworm. Earthworms are efficient in digesting the waste and get as vermicompost which contains high amount of nutrients, beneficial microorganism viz., Azotobacter, Azospirillum and Phosphobacteria, growth promoting substances viz., indole acetic acid and gibberelic acid. Vermicompost contains 1.5 % nitrogen, 0.5 % phosphorus and 0.8 % potassium in addition it contains other micronutrients. Vermicompost is the single source of all the nutrients required for the crop. Vermicompost also contains 10 % organic carbon and when continuous application of vermicompost increased the organic matter content of soil significantly.
Apart from nutrient addition and improvement of organic matter, vermicompost addition to soil improve the physical properties of soil such as soil porosity, soil aggregation, water and nutrient conservation in the soil. A farmer can produce his own vermicompost from the biodegradable waste generated in his own farm and need not spend extra money to purchase vermicompost. In addition, farmers will get additional revenue through sale of earthworm, which increases the population by 30 % in one vermicompost production cycle. 3.4.Management of treated pulp and paper mill effluentPulp and paper industry is one of the largest consumers of water. Nearly 80 % of fresh water used in the paper and pulp mill is discharged as effluent containing organic and inorganic pollutants requiring treatment and disposal. The treated paper mill effluent application to lands is considered to be an innovative approach for its disposal. By this, the effluent is not only kept out of the surface waters, but also implies in recycling where pollutants become nutrients for plant growth, thus reducing the pollution problems. Today there are about 406 mills in India with 34 in the large scale sector and 372 in the medium and small scale sector. The annual installed capacity is 6.2 million tons. The pulp and paper mill industry is segmented as wood/forest based, agro based and waste paper based with the former accounting for 43 per cent, agro based 28 per cent and waste paper based, 29 per cent of the total installed capacity. The private agency scheme entitled “Evaluation of long term-effect on the utilization of effluent water from TNPL for irrigation” sponsored by Tamil Nadu Newsprints and papers limited is functioning in this department since 1993 with a budget outlay of Rs. 35 lakhs. The treated effluent leaving TNPL was analysed over a period of ten years (1993-2003) and the results revealed that the treated effluent had varying values of physico-chemical and biological properties but within the limits of TNSPCB norms for land application. The field experiments conducted at Model Farm, Moolimangalam, Pugalur revealed that the treated TNPL effluent can safely be used for irrigation with appropriate amendments viz., pressmud @ 5 t ha-1, fortified pressmud @ 25 t ha-1 or daincha as in situ green manure. Though there were perceptible changes in soil pH, EC, available NPK, exchangeable cations, exchangeable sodium per cent (ESP) and sodium absorption ration (SAR), there was no detrimental effect due to sodium either on soil or plants (yield & quality) in sandy loam soils with good drainage facilities, The following crops and varieties were found to be suitable for cultivation along with appropriate amendments and recommended levels of NPK fertilizers: Rice : IR- 20, TRY 1, CO 43 Maize : CO 1 Sunflower : CO 2 Groundnut : TMV 2, TMV 7 Soybean : CO 1 Sugarcane : COC 92061, COC 671, COC 6304, COC 91604 Fodder grasses : Cumbu-Napier hybrid, Paragrass, Guinea grass Certain oil seed crops like gingelly and castor, pulses like greengram and blackgram were found to be sensitive for effluent irrigation. A combined culture of Trichoderma viride, Pleurotus sajor caju and EM4 (Bacterial culture) are found more efficient in degrading the solid wastes viz., bagasse pith, activated sludge and ETP sludge mixed at 2:1:1 ratio within 10 weeks of aerobic composting. The bagasse pith biomanure is rich in essential nutrients besides favorable C/N ratio for crop growth. On going experiments in Paper and pulp industries · Eucalyptus clonal trial at Moolimangalam Model Farm · Screening of tapioca varieties under effluent irrigation (TEWLIS- Farmer’s field at Pondipalayam) · Fertigation of treated TNPL effluent on yield and quality of banana (TEWLIS –Farmer’s field at Pondipalyam) · Continuous monitoring of soil and ground water quality in benchmark sites of TEWLIS area. · Identification and characterization of fungal isolates for color and phenol degradation. · Screening macrophytes for constructed wetlands to remove color and chlorophenols.
3.5.Tannery Pollution ResearchLeather production is a major industry in India which makes a significant contribution to the country’s foreign exchange earning and provides employment opportunity to about 3 million people. It is estimated that 30-35 L of water is used per kilogram of leather processed, generating about 680 * 106 L of effluent daily. During the process of leather making several chemicals like Cr(SO4)3, NaCl, Ca(OH)2, H2SO4, etc., are extensively used. Therefore the resultant effluent is enriched with chromium (Cr) and salts (NaCl and SO4). Indiscriminate disposal of ‘chemicals rich’ tannery effluent resulted extensive degradation of productive agriculture land and surface and groundwater. Chromium present in effluent is primarily in the less toxic trivalent form (Cr(III)).When this effluent is discharged into the soil, due to varying environmental condition, Cr(III) is oxidized to toxic hexavalent form which seldom remains as(Cr(VI)). Study conducted on Reed bed system for treating the tannery effluent was found very effective in achieving a total removal of Cr from the tannery effluent. However, more than 90 per cent reduction in BOD and COD could be achieved by planting macrophytes in the beds. Better performance of Arundo was observed than Typha tried in the system. · Treated tannery effluent with 50% dilution can be safely used for cultivation of flower crops like gundumalli, jathimalli and tuberose. · Plantation trees offer another avenue for the remediation of chromium contaminated soils. The degree of tolerance towards chromium rich effluent irrigation was in the order of Casuarina > Acasia > Eucalyptus. · Biological wastes such as saw dust, rice husk and coirpith are extremely effective in removing the toxic chromium in the tannery effluent. 3.6.Textile and Dye Effluent Management Waste water from the textile industry contains a variety of polluting substances like excessive salts and dyes which make the soil saline. The presence of colour in the effluent pollutes the water bodies and prevents the penetration of light, which in turn reduces the photosynthetic activities of aquatic flora. Since the physical, chemical and physicochemical methods of colour removal are expensive, microbial methods were employed to reduce the colour and pollution load of the effluents. Among the bacterial cultures, Bacillus sp-2 recorded the highest percentage (91.91) of colour reduction in the dye effluent. In case of fungal strains and standard fungal culture, the standard culture recorded maximum colour reduction of 87.21% in seven days followed by wild strains of Phanerochaete sp. (82.01%) and Trametes sp. (76.07%). Chemical mutation was carried out and the mutants of Bacillus sp. 1 and 2 reduced the colour of dye effluent by 94.31% and 94.65% and Trametes sp. by 90.74%. The survey conducted along the course of Noyyal river from Tirupur to Orathupalayam dam revealed that the soil did not reach the category of problem soil but the quality of irrigation water was poor having a pH of > 8.12 and EC of > 6.4 dS m-1. The sludge contained 16.6 % of total Ca and also other essential nutrients like S and K, thereby its ameliorative potential for the reclamation of acid and alkali soils was evaluated. The sludge application increased the plant height, DMP, seed yield and uptake of N, P, K, Ca and S by Sunflower crop.
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Salient Research Findings of the Department § Developed test kit to identify the microbial failures in biogas digesters. § Leafy biomass such as Pathenium, Tridax and Gliricidia were found to be the better substrates for biogas production. § Rate of biomethanation was high under thermophilic condition than in mesophilic condition. § Thermophilic clostridia isolated from biogas digester are very effective in degrading lignocellulosic wastes. § Spent mushroom substrate can be effectively converted to an value added organic manure by the addition of microbial accelerators. § The amount of compensation payable to the farmers of Vellore District due tannery effluent pollution was worked out and the report was submitted to the Loss of Ecology Authority. § Biocomposting of agricultural residues in combination with yeast sludge which is a distiller waste (5:1) is an economically feasible and environmentally safe option for the disposal of sugar industry wastes. § One time application of spentwash to soil as liquid manure enhanced the plant growth and productivity of maize and sunflower. § Treated tannery effluent with 50 % dilution can be safely used for cultivation of flower crops like gundumalli, jatimalli and tuberose. § Plantation trees offer another avenue for the phytoremediation of chromium contaminated soils. The degree of tolerance towards chromium rich effluent irrigation was in the order of Casuarina > Acacia > Eucalyptus. § Biological wastes such as saw dust, rice husk and coirpith are extremely effective in removing the toxic chromium in the tannery effluent. § ICI Pharama wastewater can be effectively used for crops with amendments such as poultry manure, pressmud and gypsum. Among the amendments, poultry manure was found to be the best. § The biosludge of ICI Pharma was found to be a good media supporting bacteria, fungi an actinomycetes. § The ICI bio sludge application upto 400 t ha -1 increased the dry matter production progressively and significantly. § Bioremediaiton with lignolytic fungal cultures along with moringa seeds was found to be a good treatment option for color removal in paper and pulp effluent. § Inoculation of dye effluent with alkalophilic cultures under aerated and enriched condition registered 58 per cent color reduction during three days of incubation. § Treated TNPL effluent can be used of irrigation as it enhances the soil nutrient status, yield and quality of sugarcane, groundnut, tapioca, sunflower and vegetables. § Farm boon and FYM are the best soil ameliorants to overcome the ill effects of continuous effluent irrigation under fodder crops in wastelands. § Among the amendments tested, pressmud performed better for fields irrigated with TNPL effluent continuously. § Vermiwash collected using the local species of earthworms was found to contain appreciable level of plant growth promoting compounds such as IAA and GA.
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4.INFRASTRUCTURAL FACILITIES The department of Environmental Sciences is located in a separate two storied building with provisions for future expansion to house second floor. It has fully furnished UG and PG laboratories and laboratories for various units. The heavy metal analytical laboratory established under the International scheme has been awarded the “Institutional Award” by the “Soil Contamination Research in Asia and the Pacific”. Excellent instrumental facilities are available for carrying out various analyses by the Scientists and research scholars as under: § Varian Gas Chromatograph § Chemito Gas Chromatograph § ECIL UV-VIS Metabolite Monitor § Pharmacia Multitemp and Multidrive Electrophoresis unit § Pharmacia FPLC systems § Reichert Jung Fluorescent Microscope § SpectrAA 2000 Atomic Absorption Spectrophotometer- Graphite furnace
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