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Subject: Environmental Science × End date: 2009 × Start date: 2007 ×
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    ThesisItemOpen Access
    A study of fixed-bed biofilm sequencing batch reactor for pollutant removal from agro-based industrial effluent
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2008-06) Singh, Mohini; Srivastava, R.K.
    Water is one of the most vital components of the earth. It is not only essential for survival of animals and plants but also occupies a unique position in industrial development of nation. The agro-based industries consume considerable quantities of water during their processes and generate large volumes of effluents which ultimately pollute the environment. In present study, the raw and primary treated starch industry effluent from Riddhi Siddhi Gluco Biols (RSGB) Ltd., Pantnagar had been selected for pollutant load study and its mitigation by development of an appropriate technology. Sequential Batch Reactor (SBR) technology is basically a fill-and-draw activated sludge process. Fixed-bed Biofilm Sequencing Batch Reactors (FbSBR) used in present study is the modified version of SBR in which fixed media is used as support for biofilm formation under aerobic conditions with altering anoxic conditions. During the start-up operation, three 18 L bioreactors were operated in batch mode for 28 days with synthetic water solution for biofilm formation and substrate stabilization. After stabilization period of 28 days, these bioreactors were operated in continuous mode with 24 hr cycle/day. The type-A and B FbSBR were fed with raw and primary treated effluent respectively while control i.e. type-C with primary treated effluent. Experiments were conducted in four periods each having different anoxicaerobic hydraulic residence times (􀈙H anoxic = 3-12 hr and 􀈙H aerobic = 6-15 hr) in order to determine the optimum HRT for highest pollutant removal. The total reaction time was kept constant at 18 hr for all operational periods. It was found that type-B FbSBR at HRT of 􀈙H anoxic = 6 hr and 􀈙H aerobic = 12 hr gave better removal efficiency for COD, BOD, TKN, total solids, total suspended solids, total dissolved solids, chloride and sulphate in comparison to the type-A and control. The experimental results indicated that anoxic and aerobic residence times in FbSBR significantly affected the system’s performance. Thus, in present study it was observed that FbSBR reduced the pollutants concentration, particularly organics and nitrogen more as compared to conventional sequential batch reactors (SBR). Therefore this technology can be considered as efficient and cost effective for the treatment of agro-based industrial effluent.
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    ThesisItemOpen Access
    Energy flow in a mountain agro-ecosystem during summer cropping in Kumaun Himalaya
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2008-06) Singh, Kundan; Singh, Vir
    Energy flow through a mountain agro-ecosystem was analysed in a cluster of five mid-altitude villages in the Pithoragarh district of the Kumaun Himalaya during summer (Kharif) cropping in 2007. Information was derived from 50 families (10 families in each village), resource persons and secondary sources. There were, on an average, 87 households per village. The average family size of the villages was 6.22. Average population per village was 476. An average land holding size was one ha. Upland rice and finger millet-pulses covered the largest area. On an average, there were 64 bullocks, 46 cows, 98 buffaloes, and 144 goats per village. Maximum amount of energy (274.50x105 kJha-1) was invested through manure (53.55 percent of the total energy), followed by chemical fertilizers (97.09 x105 kJha-1) and pesticides (82.88 x105 kJha-1), and minimum through seeds (15.15x105 kJha-1). In the form of useful outputs (grain and straw), a gross energy value of 10260.95 x105kJha-1 was harvested during summer cropping. The largest amount of energy was produced through fruit production (3246.60x105kJha-1), which was about 32 percent of the gross energy produced in one ha cropland during summer season. Gross energy output - input ratio of the tree-based fruit crops was the highest (61.291) of all the crops. Root and tuber crops showed comparatively higher energetic efficiency (17.833) than other vegetables (9.471). Amongst the food grain crops the maximum energetic efficiency (37.782) was recorded in amaranth-kidney bean cultivation followed by finger millet-pulses (23.884) and the minimum in soybean cultivation (3.438) The livestock population (converted into cattle units) consumed 144638094.9 kJ per day or 52792904649 kJ in a year and, in turn, produced 8490715137.07 kJ in a year through dung, 2056277724 kJ though milk, 60704289.30kJ through calf crop and 6416.35 kJ by means of draught power supply to crop fields. The gross energy produced by livestock was 10607703567kJ per year. The largest proportion of the output energy was received through dung (80 percent), followed by milk (19 percent). Contribution of calf crop and of draught animal power (DAP) was minimal compared to the overall energy. The gross energetic efficiency of livestock production was 20.09 percent. Energy for maintenance and growth available for livestock was 25.15 percent. A substantial proportion of energy in a mountain agro-ecosystem, thus, flows through livestock component. The energy flow considerations in an agro-ecosystem are of phenomenal socio-economic importance for realizing food security, social progress and sustainable development which are rooted into an agro-ecosystem and are influenced by ecosystem functioning, which in turn, is influenced by the skills and level of resource management.