Anaerobic Co-Digestion of Oil Sludge with Corn Stover for Efficient Biogas Production

Qian Yang,Chenxi Zhang,Weijie Xu,Lei Li

doi:10.3390/su12051861

Abstract

The feasibility of anaerobic co-digestion for the utilization of oil sludge was verified using corn stover, to assess the influence of different raw material ratios and inoculum volumes on the properties of the generated gas. The anaerobic co-digestion method is a novel treatment technology, which may help to solve the problem of pollution by hazardous waste oil sand from the oil exploitation and smelting process. Results showed that single-oil sludge was not suitable for gas production as a digestive substrate due to the lack of organic materials and possible hazardous materials. With the increase in the quality of exogenous organic matter (corn stover), the cumulative gas production volume was proportional to the amount of corn stover material added. It was established that when the mass ratio of corn stover to oil sludge was 4:1, the gas production performance was optimal, with a cumulative gas yield of 1222.5 mL using an inoculum volume of 30 mL. The results of this study provide a fundamental parameter baseline for the treatment of oil sludge and the improvement of gas production efficiency.

Highlights

Oil sludge is a mixture of mud and sand contaminated by crude oil in the process of oil extraction, storage, transportation and processing [1]
In order to verify the feasibility of oil sludge as a feedstock for anaerobic co-digestion, pure oil sludge exhibited a low level of biogas production compared to production with co-digestion (Figure 2)
Biogas production was the highest in the initial stage of co-digestion, and background organic matter was consumed before the inoculum was added to the fermentation bottle, the organic matter present in the inoculum allowed production to continue throughout the whole process

Summary

Introduction

Oil sludge is a mixture of mud and sand contaminated by crude oil in the process of oil extraction, storage, transportation and processing [1]. Oil sludge contains a large quantity of hydrocarbons and heavy metal components [2,3,4]. Long-term open stacking pollutes the atmospheric environment and occupies a large amount of land resources [5,6]. In China, the annual output of oil sludge in the petrochemical industry is expected to be 3 million tons [7]. It is estimated that approximately 1 ton of oil sludge is produced for every 500 tons of crude oil processed [8]. Traditional oil sludge disposal methods mainly include incineration, land cultivation, and landfilling, but these methods are costly to carry out and pose environmental risks [9,10,11]. In order to effectively solve the problem of oil sludge treatment and promote the sustainable development of the oilfield and refinery industry, it is imperative to explore environmentally-friendly, efficient and economical oil sludge treatment technologies

Methods

Results

Conclusion