Overview of Oil-containing Wastewater in Shale Oil Production
Oil-containing wastewater in shale oil production is a significant environmental issue, and its generation, characteristics, and treatment methods have received considerable attention. Below is a detailed analysis of oil-containing wastewater in shale oil production:
1. Generation of Oil-containing Wastewater
During shale oil production, the generation of oil-containing wastewater mainly comes from the following sources:
- Wastewater from the retorting unit: This is the primary source of oil shale retorting wastewater, including water brought into the furnace with shale, water from the saturated main air stream, water from evaporative ponds, and small amounts of water generated by chemical reactions. These waters go through the entire oil shale retorting process and become oil-containing wastewater.
- Wastewater from retorted material washing: During the washing and processing of retorted material, washing of gas, and recovery of shale oil, a large amount of oil-containing wastewater is produced.
- Wastewater from cooling cycles: Oil-containing wastewater is also generated during the cooling of circulating gas and the cooling of pumps.
- Wastewater from the storage tank area: During the dehydration of finished shale oil in measurement and storage tanks, a certain amount of oil-containing wastewater is produced.
2. Characteristics of Oil-containing Wastewater
The oil-containing wastewater in shale oil production has the following characteristics:
- High organic content: The wastewater contains a large amount of organic substances, such as volatile phenols, petroleum, etc.
- High ammonia nitrogen content: The wastewater is rich in nitrogenous compounds, especially ammonia nitrogen.
- Other pollutants: The wastewater also contains pollutants such as sulfides, cyanides, and other substances.
- Difficulty in biochemical degradation: Due to the high content of aromatics and oxygen-containing compounds in the wastewater, these substances inhibit microbial activity, making the wastewater extremely difficult to biodegrade.
