Biogas is one of the promising sources of alternate energy at farm level. The main raw material used for biogas production is cattle dung and most of the biogas plants installed in India are operated at 10 per cent total solids concentration. To achieve this, equal quantity of water should be added with dung and this large quantity of water required for operation of biogas plants is a major constraint in propagation of biogas technology in rural areas, particularly in water scarce regions of

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... country. Also, handling and management of digested slurry under field conditions are the main problem faced frequently. To overcome the above said problems, a study was undertaken to evaluate the performance of cattle dung in solid-state in fixed dome type biogas plant under water scarce region. Ten units of modified biogas plants were installed at farmers' sites based on solid state fermentation technology under operational research demonstration project by Dr. Panjabrao Deshmukh Agricultural University, Akola. Average biogas production 203 liters per kg DM with methane content of 60 per cent was found in 2 m 3 capacity modified Janta biogas plant. The average percentage of nitrogen, phosphorus and potassium content in digestesd slurry were higher i.e., 1.40, 1.09 and 0.46 per cent in solid state fermentation of cattle dung. There was a saving in time for cattle dung feeding to biogas plant and it was also easier for removal of digested slurry from biogas plant outlet. All the plants were working satisfactorily without any problems. This user-friendly modified Janta biogas plant based on solid state fermentation technology needs minimum or no water for its operation, therefore it was recommended for water scarcity region. Keywords: Design, Biogas, digested slurry, renewable energy and solid state fermentation 1.0 INTRODUCTION naerobic digestion of fresh cattle dung (without mixing water) and many other agro-residues at initial TSC varying between 16-25 % was demonstrated in laboratory scale and field scale digester by many Institutions. This process is known as solid state anaerobic digestion of biomass. It requires much smaller quantity of water which makes handling of the digested slurry easier, utilizes a variety of agro-residue as substrate and conserves nutrients in the digested slurry which is excellent manure for crop cultivation. The site may look much cleaner than common biogas plants and may help overcome farmer's reluctance to locate the plant near their houses. The Dr. Panjabrao Deshmukh Agricultural University had modified and installed Janta biogas plant of 2-10 m 3 capacity at farmer's sites for digestion of cattle dung in solid state [12] and [13]. Hall conducted an experiment on a 10:1 packed bed anaerobic digester with a 26.5 % total solid mixture of cattle manure and straw. The average gas yield was 0.22 m 3