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Published on: April 26, 2024
Oil refinery sludge and green waste simulated windrow composting
M S Fountoulakis1, S Terzakis, E Georgaki
1School of Agricultural Technology, Technological Educational Institute of Crete, Stavromenos, Heraklion, Crete, Greece. mfountoul@steg.teiher.gr
Biodegradation
|August 2, 2008
Summary
Oil refinery sludge (ORS) composting with green wastes (GW) showed that a higher GW ratio (1:3) led to better temperature and pollutant removal. The 1:1 ratio experienced toxic effects, delaying decomposition and reducing efficiency.
Area of Science:
- Environmental Science
- Waste Management
- Bioremediation
Background:
- Oil refinery sludge (ORS) presents a significant disposal challenge due to its organic and hydrocarbon content.
- Green wastes (GW) are abundant and biodegradable, offering potential as a co-composting agent.
- Composting is a viable biological treatment for hazardous waste, reducing pollutant levels.
Purpose of the Study:
- To evaluate the composting efficiency of oil refinery sludge (ORS) mixed with shredded green wastes (GW) at different ratios.
- To assess the impact of ORS:GW ratios on temperature, pollutant degradation (mineral oil and grease - MOG, polycyclic aromatic hydrocarbons - PAHs), and gaseous emissions.
- To investigate the role of co-digestion and potential toxicity in the composting process.
Main Methods:
- Two mixtures of ORS and GW were prepared at 1:1 (RI) and 1:3 (RII) volume ratios.
- Composting was conducted in insulated cubic containers simulating a windrow system for 120 days.
- Parameters monitored included temperature, MOG and PAHs concentrations, CO2 and CH4 emissions, and microbial presence.
Main Results:
- The 1:3 ratio (RII) reached higher temperatures (up to 62°C) and maintained thermophilic conditions for longer periods (>40 days) compared to the 1:1 ratio (RI, max 53°C).
- RII showed greater reduction in MOG (62.1%) and PAHs compared to RI (52.1% MOG reduction).
- Higher CO2 emissions were observed in RII, while RI exhibited higher CH4 emissions, suggesting delayed decomposition and potential toxicity in RI.
Conclusions:
- A higher proportion of green wastes (1:3 ratio) in co-composting with oil refinery sludge enhances the thermophilic phase and improves the degradation of MOG and PAHs.
- The lower ratio of green wastes (1:1) likely resulted in a toxic effect from the oil refinery sludge, inhibiting microbial activity and delaying the composting process.
- Temperature alone contributes to at least 15% of MOG and PAHs removal, but optimal biological activity is crucial for efficient bioremediation.
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