Optimization of Combined In-Vessel Composting Process and Chemical Oxidation for Remediation of Bottom Sludge of Crude Oil Storage Tanks Publisher Pubmed



Koolivand A¹ ; Naddafi K² ; Nabizadeh R² ; Saeedi R³ Show Affiliations
Source: Environmental Technology (United Kingdom) Published:2018

Abstract

In this research, removal of petroleum hydrocarbons from oily sludge of crude oil storage tanks was investigated under the optimized conditions of in-vessel composting process and chemical oxidation with H2O2 and Fenton. After determining the optimum conditions, the sludge was pre-treated with the optimum state of the oxidation process. Then, the determined optimum ratios of the sludge to immature compost were composted at a C:N:P ratio of 100:5:1 and moisture content of 55% for a period of 10 weeks. Finally, both pre-treated and composted mixtures were again oxidized with the optimum conditions of the oxidants. Results showed that total petroleum hydrocarbons (TPH) removal of the 1:8 and 1:10 composting reactors which were pre-treated with H2O2 were 88.34% and 90.4%, respectively. In addition, reduction of TPH in 1:8 and 1:10 composting reactors which were pre-treated with Fenton were 83.90% and 84.40%, respectively. Without applying the pre-treatment step, the composting reactors had a removal rate of about 80%. Therefore, pre-treatment of the reactors increased the TPH removal. However, post-oxidation of both pre-treated and composted mixtures reduced only 13–16% of TPH. Based on the results, remarkable overall removal of TPH (about 99%) was achieved by using chemical oxidation and subsequent composting process. The study showed that chemical oxidation with H2O2 followed by in-vessel composting is a viable choice for the remediation of the sludge. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.