微量Co对餐厨垃圾厌氧消化的影响研究

Effect of trace Co on the anaerobic digestion of food wastes

针对餐厨垃圾厌氧消化酸抑制而造成的消化效率低和产气量低等问题，采用中温（35℃）厌氧消化研究了微量co对餐厨垃圾厌氧消化过程中的pH值、挥发性脂肪酸（VFA）、COD、产气速率及产气量的影响。结果表明：投加0．25～2．00mg／（L·d）的微量co均可以改善餐厨垃圾单相厌氧消化酸抑制的现象。至第25d反应结束，C1～C4组（Co投加量分别为0．25mg／（d·L）、0．50mg／（d·L）、1．00mg／（d·L）和2．00mg／（d·L））的COD的去除率分别比CK（对照）组的高5．75％、10．91％、7．97％和4．74％。CK的产气速率峰值和累积产气量分别为867mL／（d·L）和13798mL／L，C1～C4处理的产气速率峰值分别为2143mL／（d·L）、3193mL／（d，L）、2204mL／（d·L）和2510mL／（d·L），其累积产气量分别达到19244mL/L、24433mL／L、20264mL／L和16989mlML。C1-C4的产气速率峰值及累积产气量分别比CK的高147．17％～268．28％和2313％～7708％。其中，投加0．50mg／（d·L）的微量Co对餐厨垃圾厌氧消化酸抑制的缓冲作用最好且其COD去除率、产气速率峰值和累积产气量最高。因此，投加0．25．2．00mg／（d·L）的微量co均有利于缓解餐厨垃圾单相厌氧消化酸抑制的发生并提高厌氧消化效率和产气效率。

Abstract ： As is well known, the acidic environment of the food waste is relatively lower in efficiency both from the point of view of energy digestion and production efficiency. This paper studies the effects of the added trace Co on the food waste＇s anaerobic digestion under 35 ℃. By adding trace Co, the pH value changing during digestion, volatile fatty acid （VFA） concentration, COD removal rate, biogas production rate and the cumulative biogas yield were analczed. Four experimental groups （C1 - C4） were prepared by adding Co with dose quantity of 0.25 mg/（d·L）, 0.50 mg/（d·L）, 1.00 mg/（d·L） and 2.00 mg/（d· L） respectively. The experimental resuhs Oemonstrate that by adding the trace amount of Co, it is possible to alleviate the inhibition function of the anaerobic digestion caused by the acidic en- vironment obviously. At the end of 25 days of our experiment, the COD removal rate for groups C1 to CA can be increased by 5.7%, 10.90%, 7.97% and 4.74% as compared with that of the control group （CK）. The maximum daily biogas production for CK happens at the day 3 with the peak rate of 867 mL/（d· L）. The cumulative biogas yield is 13 978 mL/L. For experimental groups of C1 to Cd, the maximum daily biogas production happens at day 4 with peak rates of 2 143 mL/（d·L）, 3 193 mL/（d·L）, 2 204 mL/（d·L） and 2 510 mL/（d· L）, respectively. The corresponding cumulative biogas yield for C1 - C4 experimental groups are 19 244 mL/L, 24 433 mL/L, 20 264 mL/L and 16 989 mL/L. Experimental group＇ s （ C1 -C4） biogas production rate is about 147.1% -268.28% higher compared with that of CK. The cumulative biogas yield for groups CI - CA is also 23.13% - 77.08% higher compared with that of CK. Experimental group C2 （0.5 mg/（d· L） added dose of Co） has the best inhibit alleviation for this anaerobic digestion process, Which has the best COD removal rate, biggest biogas production rate and maxi- mum biogas yield. Therefore, with the added trace amount of Co, it is beneficial to alleviate the acid inhibition as well as increase the di- gestion efficiency and gas production for anaerobic digestion of food wastes.