A Study of Solidification of Oily Sludge with Cement and Binding Agents

Abstract

In this work we studied the treatment of oily sludge, waste from petroleum refinery, by solidificationmethod using cement and other binding materials which were lignite fly ash (F), lime (L) and diatomaceous earth(D). The oil content was 30.56 wt% and the concentrations of heavy metals: zinc, lead, cadmium, nickel andchromium were 9.27, 18.55, 0.20, 5.46 and 21.20 ppm respectively. Since high content of oil in sludge affected thesetting and the development characteristics of concrete, therefore we extracted some oil with hexane to reducethe content to 15.21wt%. Oily sludge and partially extracted oily sludge were subjected to solidification withcement (P) and other combination of binding agents. The results demonstrated that solidified materials withoutoily sludge, the combination of PF yielded the highest compress strength at 270 kg/cm², while the othercombinations of PFL, PLD and PFLD yielded almost the same value of ca 80 kg/cm². Solidified materials withoily sludge and with partially extracted sludge yielded the compress strength ca 150-200 kg/cm², while the othercombinations of PFL, PLD and PFLD yielded compress strength over 3.5 kg/cm², the standard set by theNotification of Ministry of Industrial No. 6. Also the heavy metals and oil released from the solidified materialsof oily sludge met the EPA standard.