-
餐厨垃圾和污泥是两种常见的有机固体废物。其中,餐厨垃圾在城市生活垃圾中的占比高达20%~45%[1],污泥年产量已经突破6×107 t (80%含水率)[2],如此巨大数量的有机固废给环境治理带来了严峻挑战。餐厨垃圾和污泥都有着含水率高、有机质丰富和易腐败发臭等特点。此外,两者均含有有害物质,如病原菌和寄生虫卵等[3-4],若不加以处理可能会危害人群健康。目前,我国处理餐厨垃圾和污泥的方法有卫生填埋、焚烧和堆肥等[5]。其中,卫生填埋需要占用大量土地并可能产生渗滤液和温室气体[6];焚烧受制于餐厨垃圾和污泥的高含水率和低热值,而且还可能产生二恶英等废气。相比之下,好氧堆肥有着操作简单、设备投资少、工艺成熟等优点,在实现有机固废“减量化、无害化和资源化”方面得到了广泛应用。
好氧堆肥的原理是利用微生物的代谢活动快速分解底物中的有机成分,在底物减量的同时产热,致使堆体迅速升温杀死其中的寄生虫和病原菌,最终形成有机肥并用于调理土壤[7-9]。单独将餐厨垃圾进行堆肥得到的腐殖质因缺乏P和K等植物营养元素,导致肥效不佳;而污泥中含有丰富的P和K等元素[6],且污泥中还存在多种分解有机物的细菌和真菌。因此,用餐厨垃圾和污泥联合堆肥,不仅能够提高堆肥效率,还可以得到更有价值的腐熟产品,故有利于这两种固体废物的资源化利用。MA等[10]将餐厨垃圾和污泥以不同比例混合进行联合生物处理,证明了餐厨垃圾和污泥协同作用下有着更好的处理效果。ZHANG等[11]研究了不同比例下,餐厨垃圾和污泥联合堆肥情况,结果表明,1∶1湿重配比下得到的腐殖质肥效较单独污泥堆肥更佳。
微生物在好氧堆肥中起着重要作用,其功能是分解有机物。但是,在自然堆肥过程中存在的微生物生长周期长,难以在短时间内实现快速堆肥;而人工筛选的微生物菌剂或腐熟堆肥因具有特定的细菌或真菌,能够有针对性地分解堆体内的有机成分,最终达到提高效率、增强肥效的目的。周营等[5]向餐厨垃圾堆肥中投加复配微生物菌剂,降低了氮素损失;JURADO等[12]发现,接种菌剂后堆体内难分解的半纤维素、纤维素和木质素的降解率分别提高了28%、21%和25%。腐熟堆肥是餐厨垃圾、污泥或粪便等的堆肥腐熟产品,具有多孔结构、含水率低等特点,并且富含微生物,将其添加至堆体中也能对堆肥起到促进作用。马强等[13]发现,在生活垃圾好氧发酵时投加腐熟污泥堆肥能够有效减少氮素损失;YANG等[6]采取覆盖和混合两种方式将腐熟堆肥加入到餐厨垃圾堆肥中,结果表明,混合添加的腐熟堆肥在减少温室气体排放和提高肥效方面有着更显著的作用。由此可见,微生物菌剂和腐熟堆肥的添加能够对好氧堆肥起到很好的促进作用。
目前,大多数研究集中在向单一堆肥组分中添加微生物菌剂或腐熟堆肥,如单独餐厨垃圾堆肥[6]、单独污泥堆肥[14]、单独猪粪堆肥[15]等,向餐厨垃圾和污泥联合好氧堆肥中投加外源菌剂或腐熟堆肥的报道较少,且其理化性质的变化尚不清楚。因此,本实验选用微生物菌剂和腐熟堆肥作为添加剂,以不添加任何外源物作为对照,并以废木屑作为膨胀剂调节C/N、含水率及孔隙率,通过测定相关理化指标和营养元素的变化,并结合腐熟指标,探究这两种添加剂对餐厨垃圾和污泥联合堆肥的影响,以期为联合堆肥研究提供参考。
微生物菌剂强化餐厨垃圾和污泥联合堆肥
Co-composting of food waste and sludge enhanced by microbial agents
-
摘要: 为探究微生物菌剂对餐厨垃圾和污泥联合好氧堆肥的影响,以餐厨垃圾和污泥(湿重1∶1)混合原料为堆肥底物,添加底物总湿重30%的废木屑作为膨胀剂,向底物中分别加入微生物菌剂和腐熟堆肥为处理组,并以不添加外源物作为对照,通过测定堆肥过程中的理化性质、腐熟效果和营养元素的变化,考察菌剂和腐熟堆肥对联合堆肥的促进作用。结果表明,微生物菌剂和腐熟堆肥的添加均能提高联合堆肥的肥效和腐熟效果,但菌剂的作用更佳。在微生物菌剂的作用下,堆体温度快速升高,并且可将高温期延长到5 d;经15 d快速堆肥,体系内含水率下降了18.31%,挥发性固体减少量达5.95%;添加菌剂的处理组在堆肥结束时的种子发芽指数最高,为258.54%,总氮浓度升高了10.70%,碳氮比减少了15%,这说明微生物菌剂有助于提高堆肥腐熟和肥效。微生物菌剂对餐厨垃圾与污泥联合好氧堆肥的减量和腐殖化有着更好的促进作用。本研究结果可为餐厨垃圾和污泥堆肥资源化处理提供参考。Abstract: The effects of inoculating microbial agents were investigated during aerobic co-composting of food waste and sludge. The mixed raw materials of food waste and sludge (wet weight 1:1) were used as the composting substrates, in which the waste sawdust with 30% of the total wet weight of the substrates was added as the conditioning agents. Microbial agents and mature compost were inoculated into the substrates as the treatment groups, and without exogenous substances inoculation was defined as CK. By measuring the changes of physical and chemical properties, maturity effects and nutrient elements in the process of composting, the promoting functions were examined in terms of microbial agents and mature compost on co-composting. The results demonstrated that both of the microbial agents and mature compost could promote the fertilizer efficiency and maturity of co-composting, but by contrast, microbial agents could bring about better results. The temperature of the pile with microbial agents increased rapidly, as well as the high temperature period was extended to 5 days. The water content of the system decreased by 18.31%, and volatile solid had a 5.95% decline. At the end of composting, the treatment group inoculated with microbial agents showed the highest germination index, which reached 258.54%. Under the function of microbial agents, the pile’s total nitrogen concentration increased by 10.70%, and its carbon nitrogen ratio showed a 15% decrease, indicating that microbial agents were conducive to improve compost maturity and fertilizer efficiency. In conclusion, microbial agents exerted a better influence on food waste and sludge aerobic co-composting, which would provide some references for the resourceful treatment of food and sludge.
-
Key words:
- microbial agents /
- food waste /
- sludge /
- composting /
- resource utilization
-
表 1 原料的主要性质
Table 1. Primary properties of the raw substrates
实验组 材料 含水率% pH TN/% TOC/% VS/% C/N CK 餐厨垃圾+污泥 66.07±0.57 6.20 1.95±0.01 49.12±0.13 84.69±0.13 25.23±0.08 T1 餐厨垃圾+污泥+菌剂 66.59±0.23 6.73 1.96±0.01 48.53±0.13 83.67±0.13 24.77 ±0.24 T2 餐厨垃圾+污泥+腐熟堆肥 66.25±0.04 6.13 1.92±0.01 48.57±0.06 83.74±0.13 25.31±0.08 -
[1] AWASTHI M K, WONG J W C, KUMAR S, et al. Biodegradation of food waste using microbial cultures producing thermostable α-amylase and cellulase under different pH and temperature[J]. Bioresource Technology, 2018, 248: 160-170. doi: 10.1016/j.biortech.2017.06.160 [2] DONG Y T, SHAN Y W, GE D D, et al. A sodium dichloroisocyanurate-based conditioning process for the improvement of sludge dewaterability and mechanism studies[J]. Journal of Environmental Management, 2021, 284: 112020. doi: 10.1016/j.jenvman.2021.112020 [3] TING C M, SELVAM A, WONG J W C. Reducing nitrogen loss and salinity during 'struvite' food waste composting by zeolite amendment[J]. Bioresource Technology, 2016, 200: 838-844. doi: 10.1016/j.biortech.2015.10.093 [4] WANG Q D, XU Q Y, DU Z L, et al. Mechanistic insights into the effects of biopolymer conversion on macroscopic physical properties of waste activated sludge during hydrothermal treatment: Importance of the Maillard reaction[J]. Science of the Total Environment, 2021, 769: 144798. doi: 10.1016/j.scitotenv.2020.144798 [5] 周营, 朱能武, 刘博文, 等. 微生物菌剂复配及强化厨余垃圾好氧堆肥效果分析[J]. 环境工程学报, 2018, 12(1): 294-303. doi: 10.12030/j.cjee.201703044 [6] YANG F, LI Y, HAN Y, et al. Performance of mature compost to control gaseous emissions in kitchen waste composting[J]. Science of the Total Environment, 2019, 657: 262-269. doi: 10.1016/j.scitotenv.2018.12.030 [7] LIN L, XU F, GE X, et al. Improving the sustainability of organic waste management practices in the food-energy-water nexus: A comparative review of anaerobic digestion and composting[J]. Renewable and Sustainable Energy Reviews, 2018, 89: 151-167. doi: 10.1016/j.rser.2018.03.025 [8] CHUKWUDI O O, VICTOR C I, VJOYCE N O, et al. Composting technology in waste stabilization: On the methods, challenges and future prospects[J]. Journal of Environmental Management, 2017, 190: 140-157. [9] CHEN Z, LI Y Z, PENG Y Y, et al. Effects of antibiotics on hydrolase activity and structure of microbial community during aerobic co-composting of food waste with sewage sludge[J]. Bioresource Technology, 2021, 321: 124506. doi: 10.1016/j.biortech.2020.124506 [10] MA J, ZHANG L, LI A. Energy-efficient co-biodrying of dewatered sludge and food waste: Synergistic enhancement and variables investigation[J]. Waste Management, 2016, 56: 411-422. doi: 10.1016/j.wasman.2016.06.007 [11] ZHANG D F, LUO W H, LI Y, et al. Performance of co-composting sewage sludge and organic fraction of municipal solid waste at different proportions[J]. Bioresource Technology, 2018, 250: 853-859. doi: 10.1016/j.biortech.2017.08.136 [12] JURADO M M, SUÁREZ-ESTRELLA F, LÓPEZ M J, et al. Enhanced turnover of organic matter fractions by microbial stimulation during lignocellulosic waste composting[J]. Bioresource Technology, 2015, 186: 15-24. doi: 10.1016/j.biortech.2015.03.059 [13] 马强, 孙英杰, 王华伟, 等. 添加腐熟污泥对生活垃圾堆肥氮素转化与损失的影响[J]. 环境工程学报, 2017, 11(7): 4325-4330. doi: 10.12030/j.cjee.201605188 [14] MA C, HU B, WEI M B, et al. Influence of matured compost inoculation on sewage sludge composting: Enzyme activity, bacterial and fungal community succession[J]. Bioresource Technology, 2019, 294: 122165. doi: 10.1016/j.biortech.2019.122165 [15] LI C N, LI H, YAO T, et al. Effects of microbial inoculation on enzyme activity, available nitrogen content, and bacterial succession during pig manure composting[J]. Bioresource Technology, 2020, 306: 123167. doi: 10.1016/j.biortech.2020.123167 [16] 王旭杰, 张文明, 常馨怡, 等 堆肥添加剂降低碳氮损失的微生物学机制研究[J]. 环境科学学报, 2021, 41(10): 4116-4127. [17] ÓSCAR J S, DIEGO A O, SANDRA M. Compost supplementation with nutrients and microorganisms in composting process[J]. Waste Management, 2017, 69: 136-153. doi: 10.1016/j.wasman.2017.08.012 [18] 中华人民共和国农业农村部. 土壤检测标准: NY/T 1121.6—2006[S]. 北京: 中国农业出版社, 2006. [19] 李昌宁, 苏明, 姚拓, 等. 微生物菌剂对猪粪堆肥过程中堆肥理化性质和优势细菌群落的影响[J]. 植物营养与肥料学报, 2020, 26(9): 1600-1611. doi: 10.11674/zwyf.20051 [20] ZHOU J M. The effect of different C/N ratios on the composting of pig manure and edible fungus residue with rice bran[J]. Compost Science & Utilization, 2017, 25(2): 120-129. [21] SONG C H, ZHANG Y L, XIA X F, et al. Effect of inoculation with a microbial consortium that degrades organic acids on the composting efficiency of food waste[J]. Microbial Biotechnology, 2018, 11(6): 1124-1136. doi: 10.1111/1751-7915.13294 [22] YU Z, TANG J, LIAO H, et al. The distinctive microbial community improves composting efficiency in a full-scale hyperthermophilic composting plant[J]. Bioresource Technology, 2018, 265: 146-154. doi: 10.1016/j.biortech.2018.06.011 [23] CHEN P C, CHIU M C, MA H W. Measuring the reduction limit of repeated recycling–a case study of the paper flow system[J]. Journal of Cleaner Production, 2016, 132: 98-107. doi: 10.1016/j.jclepro.2015.04.023 [24] CHANG R X, LI Y M, CHEN Q, et al. Comparing the effects of three in situ methods on nitrogen loss control, temperature dynamics and maturity during composting of agricultural wastes with a stage of temperatures over 70 ℃[J]. Journal of Environmental Management, 2019, 230: 119-127. [25] VALERIIA S, GALYNA K, OLGA S, et al. Study of the Conditions for Accelerating the Composting Process when Adding Microbial Communities[J]. Journal of Ecological Engineering, 2021, 22(3): 11-17. doi: 10.12911/22998993/132603 [26] 李赟, 袁京, 李国学, 等. 辅料添加对厨余垃圾快速堆肥腐熟度和臭气排放的影响[J]. 中国环境科学, 2017, 37(3): 1031-1039. [27] KHALIL A, DOMEIZEL M, PRUDENT P. Monitoring of green waste composting process based on redox potential[J]. Bioresource Technology, 2008, 99(14): 6037-6045. doi: 10.1016/j.biortech.2007.11.043 [28] PARK G, NAM J, KIM J, et al. Structure and Mechanism of Surfactin Peptide from Bacillus velezensis Antagonistic to Fungi Plant Pathogens[J]. Bulletin of the Korean Chemical Society, 2019, 40(7): 704-709. doi: 10.1002/bkcs.11757 [29] GU W J, LU Y S, TAN Z Y, et al. Fungi diversity from different depths and times in chicken manure waste static aerobic composting[J]. Bioresource Technology, 2017, 239: 447-453. doi: 10.1016/j.biortech.2017.04.047 [30] YUAN J, CHADWICK D, ZHANG D, et al. Effects of aeration rate on maturity and gaseous emissions during sewage sludge composting[J]. Waste Management, 2016, 56: 403-410. doi: 10.1016/j.wasman.2016.07.017