Thickness, Distribution and Quality Assessment of Gopalganj-Madaripur Peat Deposits: A Case Study of Potential Economic Opportunities in Mid-Eastern Low-Lying Bangladesh

Abstract

The present research work illustrates the extent, distribution and a generalized quality assessment of southern low-lying peat deposits in Madaripur and part of Gopalganj district that covers approximately 17,000 hectare areas. Based on the survey of 800 boreholes, drilled in this region at different times by several government and non-government organizations for the purposes of peat exploration and hydrogeological investigation, reveals that the study area is composed of a considerable amount of peat deposits in various localities among which the deposits at Baghia-Chanda beel in Madaripur and Gopalganj districts are the most remarkable. The average peat thickness ( in-situ condition), studied during field investigation, is 6.5 feet for the upper peat deposits, overlying with an average of 3.5 feet of alluvium cover, followed by the lower peat layer of about 3 feet thick that begins at an average depth of 8 feet and separated by a thin bluish grey silty clay sediments from the upper one. The lower part of the study area, locally known as beels, is the most prospective region for peat, whereas the western part is less potential either having no peat intersection or minimal peat thickness. The overburden covers, on the other hand are inversely correlated with the peat thicknesses, i.e. , thick overburden tend to correlate with thin peat deposits and the thickest peat intersections have no or minimal overburden. Due to the variation in bulk density and peat depth, this Holocene peat has an average of 59.10% carbon stock. Nitrogen levels, more than 3%, indicate that the peat developed from the decomposition of reeds, sedges, bushes and trunks of trees (higher in nitrogen) rather than either moss or grass (lower in nitrogen). Higher sulphur content (about 2.7%) reflected the influence of brackish environments where the formation of FeS 2 took place in the roots of existing vegetation. The calorific values, about 1308.8 k-cal/kg (after 20% moisture reduction), suggest that the Gopalganj-Madaripur peat is a low grade fuel that can be used as an alternative energy source in the domestic and limited industrial purposes , to relatively expensive natural gas and coal .