Enhanced refinery oil sludge biodegradation in the presence of sewage sludge

• Main Authors: Chua, C.-L., Isa, M.H., Kutty, S.R.M., Malakahmad, A.
• Format: Conference or Workshop Item
• Published: 2009
• Subjects: TD Environmental technology. Sanitary engineering
• Online Access: http://eprints.utp.edu.my/1905/1/Enhanced_refinery_oil_sludge_biodegradation_in_the_presence_of_sewage_sludge.pdf; http://eprints.utp.edu.my/1905/

The present study focuses on the feasibility of cocomposting petroleum refinery oil sludge with sewage sludge to enhance biodegradation of the former. Six laboratory scale composters, each containing 5 kg soil spiked with 10% oil sludge (mass basis) were used for the bioremediation study. Shredded grass was used as bulking agent at a soil:grass ratio of 1:0.5 (v/v). The C/N and C/P ratios of the composting mixtures were adjusted to 20:1 and 800:1 using urea (H2NCONH2) and potassium dihydrogen phosphate (KH2PO4) respectively. The ratio of contaminated soil to sewage sludge was varied as 1:0 (control), 1:0.1, 1:0.3, 1:0.5, 1:0.7 and 1:1. The moisture content was adjusted to 20% and the experiment was conducted at room temperature for a nine week period. The results showed enhanced oil biodegradation due to sewage sludge addition. The optimum contaminated soil:sewage sludge ratio was 1:0.5 at which the oil removal was 65.6% and the reaction rate constant was 0.0139 per day (10% higher than that of the control composter). The remaining 34.4% oil and grease was considered recalcitrant and not available to micro-organisms. The experiment also demonstrated the feasibility of composting at low temperatures (23-25 °C).