厌氧发酵液回流降解含重金属水稻秸秆

针对含重金属水稻秸秆厌氧发酵过程产生的含重金属发酵液的处置问题，将其作为接种物对水稻秸秆进行回流，探究其反复回用以处理含重金属水稻秸秆的可能性。研究结果表明:厌氧发酵液回流可降解含重金属水稻秸秆，接种厌氧发酵液有助于降解水稻秸秆中木质素和半纤维素，水稻秸秆厌氧发酵释放的重金属对其厌氧发酵过程未产生明显抑制作用。在固液比为3.3%条件下，接种发酵液后含重金属水稻秸秆总甲烷产量和总产气量分别达到121.2，282.6 mL/g VS。秸秆中Cu、Cd、Pb和Zn的释放率分别达到94.22%、54.21%、72.67%和98.55%，沼渣中重金属含量达到GB 8172—87《城镇垃圾农用控制标准》要求，可实现还田利用。发酵结束后，发酵液中Cu、Cd、Pb和Zn浓度分别为0.30，0.073，0.10，2.57 mg/L。结果表明，接种厌氧发酵液可以促进水稻秸秆中重金属释放，进而实现含重金属秸秆和发酵液的联合处置。

ANAEROBIC FERMENTATION SLURRY RECYCLED FOR DEGRADATION OF HEAVY METAL-CONTAINING RICE STRAW

In this study, the disposal possibility of anaerobic fermentation slurry produced in the process of anaerobic fermentation for heavy metal-containing rice straw was studied. The results showed that the circulation reflux of anaerobic fermentation slurry could accelerate the degradation of rice straw, including cellulose and hemicellulose. Meanwhile, the heavy metals released from rice straw in the anaerobic fermentation process was similar to that with original anaerobic fermentation slurry. The methane yields of 121.2, 282.6 mL/g VS was achieved under the solid to liquid ratio of 3.3%. Furthermore, the release percentages of Cu, Cd, Pb and Zn from rice straw arrived to 94.22%, 54.21%, 72.67% and 98.55%, respectively. The content of heavy metals in straw residues was significantly lower than the levels for the Urban Garbage Agricultural Control Standard in China (GB 8172-87) and could be backed to the field. After fermentation, the concentration of Cu, Cd, Pb and Zn in anaerobic fermentation slurry were 0.30, 0.073, 0.10, 2.57 mg/L respectively. The results showed that the anaerobic fermentation slurry recycled was available for the anaerobic fermentation of heavy metals-containing rice straw and beneficial to the release of heavy metals from rice straw.