Co-composting of Petroleum Sludge with Poultry Manure

Abstract

Petroleum sludge (PS) is a well-known hazardous waste because of its complicated compound. Leaching of petroleum sludge becomes a major threat to the environment if the waste is dumped illegally in landfills without proper treatment. Since, the petroleum sludge has the tendency to infiltrate into ground, eventually contaminates the soil and ground water. Therefore, the petroleum sludge needs to be treated before disposal to eliminate the negative impact to the environment. In this study, composting of PS by adding sawdust, soil and poultry manure has been carried out to produce compost that is low in polycyclic aromatic hydrocarbons (PAHs), heavy metals and with higher nutrient content. Each of the compost combination was homogenously mixed and stored in plastic container with good aeration using various ratios of 1:1:1:0 (control), 1:1:1:5, 1:1:1:8 and 1:1:1:10 volume-volume basis respectively, for two weeks. The result for PAHs by using Gas Chromatography/ Mass Spectrophotometry (GC/MS) shows fourteen types of PAH detected in PS. The total reduction of PAH in composts mixed were found to be 0.97%, 2.44%, 3,43% and 2.53% in compost design mix of 1:1:1:0, 1:1:1:5, 1:1:1:8 and 1:1:1:10, respectively. Besides, the result for heavy metals such as Al, Fe, Cu, Zn, Pb and Cd by using Atomic Absorption Spectrometer (AAS) shows the concentration in Fe (450.65) > Al (338.07) > Zn (52.7) > Pb (40.73) > Cd (39.56) > Cu (19.56) ppm. The best heavy metals reduction occurs to be in ratio of 1:1:1:10 where the Al, Fe, Cu, Zn, Pb and Cd decreased by 3.05%, 2.67%, 3.37%, 0.11%, 9.16% and 6.45% respectively. The carbon and nitrogen content in each ratio were determined by Total Organic Carbon (TOC) analysis and Total Kjedahl Nitrogen (TKN) analysis during the composting period. The Carbon to Nitrogen (C:N) ratio was maintained between 25 to 30 throughout the composting period. The composting process created a favorable condition for the microbial degradation of PS. Hence, based on the results obtained, best performing ratio to treat PS has been confirmed with ratio of 1:1:1:8. As a conclusion, co-composting can be a promising treatment method for disposal of PS.