DESCRIPTION: Biogas plant using clay segments is 25 to 30% cheaper than the conventional design using brick masonary. It can be fabricated in rural areas with local materials, giving a new source of employment to potters and non-potters too. The plant can also serve as a water storage tank.
CONSTRUCTION: Each clay segment is of the dimension of 2" x 1" x 2.5". The segments are fabricated using wooden moulds and fired slowly in the updraft kiln at temperature of about 850"C to avoid cracking. The interlocking arrangement provided at edges helps to form a good joint with the help of cement-mortar (Fig. 3). The digester is constructed in the pit by joining segments at their edges to form concentric rings and arranging required number of rings one above the other using cement mortar. The slightly curved surface of the segment helps in easy construction of concentric rings of varying diameters required for different sizes of gas plant. The wall of the digester is internally lined with cement paste instead of plastering with cement mortar.
For construction of fixed dome, the triangular and slightly curved segments, each of size 3" x 2" x 2", are made using wooden mould. (fig. 4). For the dome of 2 gas plant, 8 such segments are required, each of which is further divided into 3 or 4 pieces before being fired. For the construction of a fixed dome, 24 to 32 segments are used, which saves some cement mortar. Since the numbers of joinaries compared to usual brick masonary are less, the use of cement is substantially reduced.
SOURCE: Centre of Science for Villages, Magan Sangrahalaya, Wardha - 442 001, Maharashtra