Treatment of high-strength opium alkaloid wastewater using hydrothermal gasification

- We studied hydrothermal gasification of opium alkaloid wastewater.
- The effects of various amounts of K2CO3, and temperature were investigated.
- Maxiumum hydrogen and methane yields were achieved with 0.5-0.625 g of catalyst.
- In the gaseous product yields, the most effective parameter was temperature.
- The highest COD and TOC removal efficiencies were reached maximum at 600 °C.

The hydrothermal gasification of opium alkaloid wastewater was investigated in a batch autoclave at 400, 500, and 600 °C at a pressure range of 23.0-45.5 MPa without and with various amount of K2CO3 catalyst. The maximum gas yields, hydrogen and methane, were obtained at 600 °C using K2CO3 at amounts higher than 0.375 g. TOC and COD contents of the aqueous products and raw wastewater were analyzed, the compounds existing in the raw wastewater and the aqueous products were identified and compared. The wastewater used in this work has a COD content of 35,000 mg O2/L and a TOC content of 15,000 mg/L and the highest COD removal efficiencies acquired was 95% at 600 °C and in the presence of K2CO3 (varying from 0.375-0.625 g). The H2 and CH4 yields were maximized at 47.7 and 34.3 mol/kg OC in wastewater using 0.5 g of K2CO3 and at 600 °C, respectively.

The effects of the catalyst amount on the gaseous product yields in hydrothermal gasification of alkaloid wastewater at various reaction temperatures ((a) 400 °C, (b) 500 °C, and (c) 600 °C).75