Enhance Biyagama water treatment plant sludge properties with natural and synthetic binders

Abstract

Alum sludge is an inevitable waste product produced in the drinking water treatment process. In the Biyagama water treatment plant the sludge generation is estimated as 10 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> per day. Shrinkage was identified as the main drawback of the sludge to use as a construction material. According to the historical evidence, natural binders were added to soil mixtures to overcome the shrinkage. Therefore, this study was conducted to identify the performances of both natural and synthetic binders to enhance the properties of Biyagama water treatment plant sludge to overcome the shrinkage. In the study styrene acrylic binder as the synthetic binder and extractions of Dawulkurundu leaf, Bhoomi bark, and Bael fruit as the natural binders were selected. In the first phase of the study, natural binders were prepared and the synthetic binder was purchased from the market. In the second phase of the study, sludge mixtures were prepared by mixing with binders in a mechanical mixer. The initial moisture content of each mix was measured according to the oven-dry method and an observational shrinkage test was conducted. Results indicated that both natural and synthetic binders affect the shrinkage in different ways according to the binder type, while increasing the adhesiveness of the mix. Different crack patterns were observed according to the binder type and the binders increased the adhesiveness of the mixture. It is concluded that both synthetic and natural binders enhanced the properties of Biyagama water treatment plant sludge, and further studies should be conducted to finalize the optimum mixing ratios of each binder type.