摘要
为了将蛋白类餐厨垃圾厌氧发酵产挥发性脂肪酸(VFAs)用作强化生物除磷过程中的碳源,实现其资源化利用,考察了在35℃条件下,pH的改变对其产酸的影响。结果表明:将起始pH调节为碱性,VFAs的产量显著高于酸性,且随着发酵时间的增加,VFAs的产量也逐渐增加,在pH=10,第8天时达到最高值36 193 mg·L~(-1),此时是初始值的28倍。其中,乙酸占50.3%,其次为丙酸30.9%。同时发现,pH调节为碱性也有利于溶解性COD(SCOD)、溶解性蛋白质(SPN)和溶解性碳水化合物(SPS)的溶出;在pH=10,第3天时SCOD和SPN分别达到最大值135 680 mg·L~(-1)和44 188 mg·L~(-1),此时是对照组的17倍和8倍。只有在强碱性条件下,SPN产量才明显提高。酸碱调节对SPS的溶出影响并不是太大,其在较短时间1 d内达到最大,然后减少并逐渐趋于稳定。通过分析可知,起始pH调节为强碱性有利于蛋白类餐厨垃圾的发酵产酸及有机质溶出的过程。
In order to use anaerobic fermentation of protein kitchen waste to produce volatile fatty acids(VFAs), it is used as a carbon source in the process of strengthening biological phosphorus removal, and its resource utilization is realized. The effect of pH change on acid production at 35?C was investigated. The results showed that when the initial pH was adjusted to alkaline, the yield of VFAs was significantly higher than that of acidity, and it gradually increased with the increase of fermentation days. When the pH is controlled at 10, the maximum VFAs of36 193 mg·L~(-1) are achieved on the 8 th day, which is 28 times of the initial value. Among them, acetic acid accounts for 50.3%, followed by 30.9% of propionic acid. At the same time, it has been found that it is beneficial to the release of soluble COD(SCOD), soluble protein(SPN) and soluble carbohydrate(SPS) under alkaline conditions. At pH 10,the maximum SCOD and SPN of 135 680 mg·L~(-1) and 44 188 mg·L~(-1) was obtained on the 3 rd day, which was 17 times and 8 times of the blank control, respectively. Under strong alkaline conditions, SPN production increased significantly. There is no significant effect of acid-base adjustment on the released amounts of SPS, it reaches a maximum in a short period(1 day),then decreases and gradually stabilizes. All in all, it is beneficial to anaerobic acidogenesis of protein food waste and more organic substrates are obtained when the adjustment of the initial pH to strong basicity.
引文
[1]陈博.我国餐厨垃圾处理行业现状分析[J].科技风,2017(17):264.
[2]梁政,杨勇华,樊洪,等.厨余垃圾处理技术及综合利用研究[J].中国资源综合利用,2004(8):36-38.
[3]张振宇.市政污泥联合不同有机质厌氧发酵产酸的试验研究[D].重庆:重庆大学,2016.
[4]郭香麟,左剑恶,史绪川,等.餐厨垃圾与秸秆混合中温和高温厌氧消化对比[J].环境科学,2017,38(7):3070-3077.DOI:10.13227/j.hjkx.201612267.
[5] FONTANILLE P, KUMAR V, CHRISTOPHE G, et al. Bioconversion of volatile fatty acids into lipids by the oleaginous yeast Yarrowia lipolytica[J]. Bioresource Technology,2012,114(3):443-449. DOI:10.1016/j.biortech.2012.02.091.
[6] CHEN Y G, LUO J Y, YAN Y Y, et al. Enhanced production of short-chain fatty acid by co-fermentation of waste activated sludge and kitchen waste under alkaline conditions and its application to microbial fuel cells[J]. Applied Energy,2013,102(2):1197-1204. DOI:10.1016/j.apenergy.2012.06.056.
[7] LI X, CHEN H, HU L F, et al. Pilot-scale waste activated sludge alkaline fermentation, fermentation liquid separation, and application of fermentation liquid to improve biological nutrient removal[J]. Environmental Science&Technology,2011,45(5):1834-1839. DOI:10.1021/es1031882.
[8] LIM S J, KIM B J, JEONG C M, et al. Anaerobic organic acid production of food waste in once-a-day feeding and drawing-off bioreactor[J]. Bioresource Technology,2008,99(16):7866-7874. DOI:10.1016/j.biortech.2007.06.028.
[9]苑宏英,张华星,陈银广,等. pH对剩余污泥厌氧发酵产生的COD、磷及氨氮的影响[J].环境科学,2006,27(7):1358-1361.
[10] ZHANG P, CHEN Y G, ZHOU Q. Waste activated sludge hydrolysis and short-chain fatty acids accumulation under mesophilic and thermophilic conditions:Effect of pH[J]. Water Research,2009,43(15):3735-3742. DOI:10.1016/j.watres.2009.05.036.
[11] LI X, CHEN Y G, ZHAO S, et al. Efficient production of optically pure L-lactic acid from food waste at ambient temperature by regulating key enzyme activity[J]. Water Research,2015,70(5):148-157. DOI:10.1016/j.watres.2014.11.049.
[12] JENKINS D, RICHARD M G, DAIGGER G T. Manual on the Causes and Control of Activated Sludge Bulking and Foaming[M].2nd ed. Florida,USA:Boca Raton,Lewis Publishers,1993:26.
[13]张波,史红钻,张丽丽,等. pH对厨余废物两相厌氧消化中水解和酸化过程的影响[J].环境科学学报,2005,25(5):665-669.
[14]蔡丽梅,孙力平,苑宏英,等.不同pH控制策略下剩余污泥中NH4+-N、PO43--P、COD溶出研究[J].环境工程学报,2010,4(10):2373-2377.
[15]崔静,董岸杰,张卫江,等.热碱水解提取污泥蛋白质的实验研究[J].环境工程学报,2009,3(10):1889-1892.
[16] CHEN Y G, JIANG S, YUAN H Y, et al. Hydrolysis and acidification of waste activated sludge at different p Hs[J]. Water Research,2007,41(3):683-689. DOI:10.1016/j.watres.2006.07.030.
[17] WANG K, YIN J, SHEN D S, et al. Anaerobic digestion of food waste for volatile fatty acids(VFAs)production with different types of inoculum:Effect of pH[J]. Bioresource Technology,2014,161(6):395-401. DOI:10.1016/j.biortech.2014.03.088.
[18]周涛,李阳,宋楠,等.电刺激对餐厨垃圾-污泥共厌氧发酵产挥发性脂肪酸的影响[J].环境工程学报,2016,10(12):7195-7201. DOI:10.12030/j.cjee.201508031.
[19]赵明星,严群,阮文权,等.碱处理对厨余垃圾厌氧发酵产氢的强化研究[J].安全与环境学报,2009,9(5):88-91.
[20]余晓琴.餐厨垃圾厌氧发酵产酸优化及蛋白质组分的产酸特性研究[D].杭州:浙江工商大学,2017.
[21]张希衡,工宝泉,刘新荣,等.废水厌氧生物处理工程[M].北京:中国环境科学出版社.1996.100-101.
[22] YU G H, HE P J, SHAO L M, et al. Toward understanding the mechanism of improving the production of volatile fatty acids from activated sludge at pH 10.0[J]. Water Research,2008,42(18):4637-4644. DOI:10.1016/j.watres.2008.08.018.
[23]陈祥.餐厨垃圾两相厌氧发酵氨氮特性与控制方法研究[D].杭州:浙江大学,2014.
[24] ELEFSINIOTIS P, WAREHAM D G. Utilization patterns of volatile fatty acids in the denitrification reaction[J]. Enzyme&Microbial Technology,2007,41(2):92-97. DOI:10.1016/j.enzmictec.2006.12.006.