Effect of Earthworm and Biochar Coupled Composting on Decomposition Process of Organic Components in Sludge

doi:10.11924/j.issn.1000-6850.casb2025-0346

Abstract

Abstract:

The purpose of this study was to investigate the effects of Eisenia foetida and corn stover biochar coupled composting on the decomposition of organic components in the mixture of sewage sludge and corn stover. Chemical testing combined with FTIR and 2DCOS technologies were applied to analyze the changes of chemical properties, organic matter composition and degradation sequence in material during composting. The results showed that by the end of composting, inoculation of earthworms could significantly reduce the pH of sludge, while adding biochar did not significantly change the pH of sludge; adding earthworms and biochar could increase the electrical conductivity (EC), total nitrogen (TN), total phosphorus (TP), and total potassium (TK) content in sludge, with earthworms having a greater effect than biochar. Adding earthworms and biochar could alter the structure of functional groups in sludge and increase the relative peak area ratio of 1633/2924. FTIR combined with 2DCOS analysis showed that the separate application of earthworms and biochar could slightly alter the degradation process of organic matter, while the coupling application of earthworms and biochar could completely change the degradation process of organic matter, shifting from preferentially decomposing aliphatic compounds to preferentially decomposing aromatic compounds. This research showed that the coupling treatment of sewage sludge with earthworms and biochar could promote the maturation of compost and improve the fertilizer efficiency of compost products. The coupling composting technology of earthworms and biochar was an effective means to ensure efficient decomposition and maturation of sewage sludge, ultimately forming high-quality organic fertilizers.

Key words: Eisenia foetida, sludge, biochar, FTIR, 2DCOS

ZHANG Jizhou, YUAN Lei, LV Pin, WANG Limin, LI Wenqi, YU Zhimin. Effect of Earthworm and Biochar Coupled Composting on Decomposition Process of Organic Components in Sludge[J]. Chinese Agricultural Science Bulletin, 2025, 41(27): 71-78.

Figures/Tables 6

References 25

[1]	QU J, WANG H, WANG K, et al. Municipal wastewater treatment in China: development history and future perspectives[J]. Frontiers of environmental science & engineering, 2019,13:88-94.
[2]	TU J C, ZHAO Q J, WEI L L, et al. Heavy metal concentration and speciation of seven representative municipal sludges from wastewater treatment plants in Northeast China[J]. Environmental monitoring and assessment, 2012,184:1645-1655.
[3]	HE X, ZHANG Y X, Shen M C, et al. Effect of vermicomposting on concentration and speciation of heavy metals in sewage sludge with additive materials[J]. Bioresource technology, 2016,218:867-873.
[4]	YUAN H, ZHANG Y, CHEN Z X, et al. Molecular transformation pathway and bioavailability of organic phosphorus in sewage sludge under vermicomposting[J]. Science of the total environment, 2024,906:167796.
[5]	PAUL S, DAS S, RAUL P, et al. Vermi-sanitization of toxic silk industry waste employing Eisenia fetida and Eudrilus eugeniae: substrate compatibility, nutrient enrichment and metal accumulation dynamics[J]. Bioresource technology, 2018,266:267-274.
[6]	RUSANESCU C O, RUSANESCU M, VOICU G, et al. The recovery of vermicompost sewage sludge in agriculture[J]. Agronomy, 2022,12:2653.
[7]	KHAN M B, CUI X Q, JILANI G, et al. Eisenia fetida and biochar synergistically alleviate the heavy metals content during valorization of biosolids via enhancing vermicompost quality[J]. Science of the total environment, 2019,684: 597-609.
[8]	MALINSKA K, GOLANSKA M, CACERES R, et al. Biochar amendment for integrated composting and vermicomposting of sewage sludge-the effect of biochar on the activity of Eisenia fetida and the obtained vermicompost[J]. Bioresource technology, 2017 225:206-214.
[9]	RAHIL D, DEACHEN A, JASWINDER S, et al. Synergistic effect of biochar amendment in milk processing industry sludge and cattle dung during the vermiremediation[J]. Bioresource technology, 2023,3711:28612.
[10]	XIE J C, XIA H, GUAN M X, et al. Accelerating the humification mechanism of dissolved organic matter using biochar during vermicomposting of dewatered sludge[J]. Waste management, 2023,159:102-113.
[11]	DUTTA R, ANGMO D, SINGH J, et al. Synergistic effect of biochar amendment in milk processing industry sludge and cattle dung during the vermiremediation[J]. Bioresource technology, 2023,371,128612.
[12]	GUO X, LI Y, FENG Y, et al. Using fluorescence quenching combined with two-dimensional correlation fluorescence spectroscopy to characterize the binding-site heterogeneity of dissolved organic matter with copper and mercury in lake sediments[J]. Environmental Chemistry, 2017,14:91-98.
[13]	YU Z M, ZHOU M, ZHANG H W, et al. Changes in Cd forms and Cd resistance genes in municipal sludge during coupled earthworm and biochar composting[J]. Ecotoxicology and environmental safety, 2024,286:17179.
[14]	DUME B, HANC A, SVEHLA P, et al. Composting and vermicomposting of sewage sludge at various C/N ratios: Technological feasibility and end-product quality[J]. Ecotoxicology and environmental safety, 2023,263:115255.
[15]	HUANG K, XIA H, WU Y, et al. Effects of earthworms on the fate of tetracycline and fluoroquinolone resistance genes of sewage sludge during vermicomposting[J]. Bioresource technology, 2018,259:32-39.
[16]	HUANG K, CHEN J, GUAN M, et al. Effects of biochars on the fate of antibiotics and their resistance genes during vermicomposting of dewatered sludge[J]. Journal of hazardous materials, 2020,397:122767.
[17]	GONG X Q, ZOU L, WANG L, et al. Biochar improves compost humification, maturity and mitigates nitrogen loss during the vermicomposting of cattle manure-maize straw[J]. Journal of environmental management, 2023,325:116432.
[18]	LIU L, YE Q Y, WU Q, et al. Effect of biochar addition on sludge aerobic composting and greenbelt utilization[J]. Environmental technology innovation, 2021,21:101279.
[19]	WU Y P, LI Q F, ZHENG Y, et al. Optimizing biochar addition for vermicomposting: a comprehensive evaluation of earthworms’ activity, N₂O emissions and compost quality[J]. Biochar, 2023, 5(1). doi.org/10.1007/s42773-022-00203-9.
[20]	NUNES R R, PIGATIN L B F, OLIVEIRA T S, et al. Vermicomposted tannery wastes in the organic cultivation of sweet pepper: growth, nutritive value and production[J]. International journal of recycling of organic waste in agriculture, 2018, 7(4):313-324.
[21]	BHAVIK K, HEMANT P, KETAN P, et al. Vermistabilization of mango tree pruning waste with five earthworm species: a biochemical and heavy metal assessment[J]. Heliyon, 2023, 9(9):19908.
[22]	DONG J, SHEN L F, SHAN S D, et al. Optimizing magnetic functionalization conditions for efﬁcient preparation of magnetic biochar and adsorption of Pb(II) from aqueous solution[J]. Science of the total environment, 2022,806:151442.
[23]	TAN Y H, WAN X R, ZHOU T, et al. Novel Zn-Fe engineered kiwi branch biochar for the removal of Pb (II) from aqueous solution[J]. Journal of hazardous materials, 2022,424:127349.
[24]	张福韬, 乔云发, 苗淑杰, 等. 长期玉米连作下黑土各组分有机质化学结构特征[J]. 中国农业科学, 2016, 49(10):1913-1924. doi: 10.3864/j.issn.0578-1752.2016.10.008
[25]	GUO X, HE X, LI C, et al. The binding properties of copper and lead onto compost-derived DOM using Fourier-transform infrared, UV-vis and fluorescence spectra combined with two-dimensional correlation analysis[J]. Journal of hazardous materials, 2019,365:457-466.

参数	污泥	秸秆	生物炭	混合物料
pH	7.59	6.31	9.01	7.34
EC/(μS/cm)	574.52	896.35	675.21	598.70
TOC/(g/kg)	290.28	480.39	560.21	338.60
TN/(g/kg)	17.80	4.81	8.32	14.91
C/N	16.42	100.57	67.33	22.83

参数	污泥	秸秆	生物炭	混合物料
pH	7.59	6.31	9.01	7.34
EC/(μS/cm)	574.52	896.35	675.21	598.70
TOC/(g/kg)	290.28	480.39	560.21	338.60
TN/(g/kg)	17.80	4.81	8.32	14.91
C/N	16.42	100.57	67.33	22.83