Chalermraj Wantawin and Pinchookorn Chobthiangtham

pp. 77 - 84

Abstract

The objective of the study is to use baghouse filter waste as a binder mixed with cement and lignite
fly ash to solidify sludge from chromium electroplating wastewater treatment. To save cost of solidification,
reducing cement in binder and increasing sludge in the cube were focused on. Minimum percent cement in
binder of 20 for solidification of chromium sludge was found when controlling lignite fly ash to baghouse
filter waste at the ratio of 30:70, sludge to binder ratio of 0.5, water to mixer ratio of 0.3 and curing time of
7 days. Increase of sludge to binder ratio from 0.5 to 0.75 and 1 resulted in increase in the minimum percent
cement in binder up to 30 percent in both ratios. With the minimum percent cement in binder, the calculated
cement to sludge ratios for samples with sludge to binder ratios of 0.5, 0.75 and 1 were 0.4, 0.4 and 0.3
respectively. Leaching chromium and compressive strength of the samples with these ratios could achieve
the solidified waste standard by the Ministry of Industry. For solidification of chromium sludge at sludge to binder ratio of 1, the lowest cost binder ratio of cement to lignite fly ash and baghouse filter waste in this
study was 30:21:49. The cost of binder in this ratio was 718 baht per ton dry sludge.