From anaerobic to aerobic treatment: upcycling of digestate as a moisturizing agent for in-vessel composting process

Abstract

In Tunisia, there are crucial challenges facing both urban and rural areas, the most prominent of which are the production of organic waste, the need for waste treatment, the demand for water and energy and the need for a circular economy. To this end, the study was designed to develop a technical concept on closed cycle ‘biowaste to bioenergy’ treating, basically food waste (FW) through combined biological processes. In this approach, the generated digestate from FW anaerobic reactors was used successfully as a moisturizing agent for FW in-vessel composting. Four types of digestate were examined to be used as moisturizing agent (MA). The selection of the appropriate MA was achieved based on technical criteria; moisture content (MC), C:N ratio and heavy metals concentrations. The findings showed that the digestate obtained from anaerobic co-digestion of food waste and wheat straw (D1) was the most efficient AD-effluent to be added. In terms of composting process performance, the thermophilic phase of the amended reactor (A1) lasted 16 days and reached higher temperatures of about 72 °C, while the unamended one (A1) was characterized by a thermophilic temperature of around 66 °C indicating that the end products were of a pathogen-free compost. When it comes to the physico-chemical factors examined demonstrating that the biological conditions were sufficiently developed. The findings showed overall decreasing profiles during the composting period for moisture, C:N ratio as well as nitrification index (NI). From the quality-point of view, it was found that heavy metal concentrations had lower limits than those values set by German standards. Moreover, all the compost samples appeared to be stable and classified as class IV and V end product.

Keywords

Biological treatment / Food waste / Digestate / Moisturizing agent / Compost / European standards / End product quality

References

[1] Abbasi S, Gajalakshmi S. Disposal of municipal solid waste with in situ termireactors: proof-of-concept. Bioresour Bioprocess, 2015, 2: 24.

[2] Abdulrahman A (2018) Solid waste management in Tunisia. EcoMENA. https://www.ecomena.org/solid-waste-management-tunisia/. Accessed 13 Jan 2020.

[3] Abu Hajar HA, Tweissi A, Abu Hajar YA, . Assessment of the municipal solid waste management sector development in Jordan towards green growth by sustainability window analysis. J Clean Prod, 2020, 258: 120539.

[4] Akyol Ç, Ince O, Ince B. Crop-based composting of lignocellulosic digestates: Focus on bacterial and fungal diversity. Bioresour Technol, 2019, 288: 121549.

[5] Al Seadi T, Drosg B, Fuchs W, . Wellinger A, Murphy J, Baxter D, . 12—biogas digestate quality and utilization. The biogas handbook, 2013, Sawston: Woodhead Publishing, 267-301.

[6] Al-Bataina BB, Young TM, Ranieri E. Effects of compost age on the release of nutrients. Int Soil Water Conserv Res, 2016, 4: 230-236.

[7] Alburquerque JA, de la Fuente C, Bernal MP. Chemical properties of anaerobic digestates affecting C and N dynamics in amended soils. Agric Ecosyst Environ, 2012, 160: 15-22.

[8] Aparcana S. Approaches to formalization of the informal waste sector into municipal solid waste management systems in low- and middle-income countries: review of barriers and success factors. Waste Manag, 2017, 61: 593-607.

[9] Arab G, McCartney D. Benefits to decomposition rates when using digestate as compost co-feedstock: part I—focus on physicochemical parameters. Waste Manag, 2017, 68: 74-84.

[10] Arafat HA, Jijakli K, Ahsan A. Environmental performance and energy recovery potential of five processes for municipal solid waste treatment. J Clean Prod, 2015, 105: 233-240.

[11] Ardhaoui K, Bellali F, Moussa M. Composting and lixiviation, case study in Médenine-Tunisia. J Res Environ Earth Sci, 2019, 7: 161-167.

[12] Ardolino F, Colaleo G, Arena U. The cleaner option for energy production from a municipal solid biowaste. J Clean Prod, 2020, 266: 121908.

[13] Asadu CO, Egbuna SO, Chime TO, . Survey on solid wastes management by composting: Optimization of key process parameters for biofertilizer synthesis from agro wastes using response surface methodology (RSM). Artif Intell Agric, 2019, 3: 52-61.

[14] Awasthi SK, Sarsaiya S, Awasthi MK, . Changes in global trends in food waste composting: research challenges and opportunities. Bioresour Technol, 2020, 299: 122555.

[15] Aydi A. Assessment of heavy metal contamination risk in soils of landfill of Bizerte (Tunisia) with a focus on application of pollution indicators. Environ Earth Sci, 2015, 74: 3019-3027.

[16] Bacenetti J. Editorial overview: water–energy–food nexus. Curr Opin Environ Sci Health, 2020, 13: A1-A4.

[17] Barthod J, Rumpel C, Dignac M-F. Composting with additives to improve organic amendments. A review. Agron Sustain Dev, 2018, 38: 17.

[18] Bazrafshan E, Zarei A, Kord Mostafapour F et al (2016) Maturity and stability evaluation of composted municipal solid wastes. In: Health scope. https://jhealthscope.com/en/articles/20165.html. Accessed 17 Mar 2020

[19] Bhatia SK, Joo H-S, Yang Y-H. Biowaste-to-bioenergy using biological methods—a mini-review. Energy Convers Manag, 2018, 177: 640-660.

[20] Cáceres R, Coromina N, Malińska K, . Nitrification during extended co-composting of extreme mixtures of green waste and solid fraction of cattle slurry to obtain growing media. Waste Manag, 2016, 58: 118-125.

[21] Cáceres R, Malińska K, Marfà O. Nitrification within composting: a review. Waste Manag, 2018, 72: 119-137.

[22] Carabassa V, Domene X, Alcañiz JM. Soil restoration using compost-like-outputs and digestates from non-source-separated urban waste as organic amendments: limitations and opportunities. J Environ Manag, 2020, 255: 109909.

[23] Casini D, Barsali T, Rizzo AM, Chiaramonti D. Production and characterization of co-composted biochar and digestate from biomass anaerobic digestion. Biomass Convers Bioref, 2019

[24] Chaher NEH, Chakchouk M, Engler N, . Optimization of food waste and biochar in-vessel co-composting. Sustainability, 2020, 12: 1356.

[25] Chaher NEH, Chakchouk M, Nassour A, . Potential of windrow food and green waste composting in Tunisia. Environ Sci Pollut Res, 2020

[26] ChenYu D, Abdullah JJ, Greetham D, . Valorization of food waste into biofertiliser and its field application. J Clean Prod, 2018, 187: 273-284.

[27] Du C, Abdullah JJ, Greetham D, . Valorization of food waste into biofertiliser and its field application. J Clean Prod, 2018, 187: 273-284.

[28] Fan H, Liao J, Abass OK, . Effects of bulking material types on water consumption and pollutant degradation in composting process with controlled addition of different liquid manures. Bioresour Technol, 2019, 288: 121517.

[29] Ferronato N, Torretta V. Waste mismanagement in developing countries: a review of global issues. Int J Environ Res Public Health, 2019, 16: 1060.

[30] Franke-Whittle IH, Confalonieri A, Insam H, . Changes in the microbial communities during co-composting of digestates. Waste Manag, 2014, 34: 632-641.

[31] Hemidat S, Jaar M, Nassour A, Nelles M. Monitoring of composting process parameters: a case study in Jordan. Waste Biomass Valoriz, 2018, 9: 2257-2274.

[32] Jemai I, Ben Aissa N, Gallali T, Chenini F. Effects of municipal reclaimed wastewater irrigation on organic and inorganic composition of soil and groundwater in Souhil Wadi Area (Nabeul, Tunisia). Hydrol Curr Res, 2013, 4: 1-8.

[33] Kim E, Lee D-H, Won S, Ahn H. Evaluation of optimum moisture content for composting of beef manure and bedding material mixtures using oxygen uptake measurement. Asian-Australas J Anim Sci, 2016, 29: 753-758.

[34] Kumar M, Ou Y-L, Lin J-G. Co-composting of green waste and food waste at low C/N ratio. Waste Manag, 2010, 30: 602-609.

[35] Li S, Li D, Li J, . Evaluation of humic substances during co-composting of sewage sludge and corn stalk under different aeration rates. Bioresour Technol, 2017, 245: 1299-1302.

[36] Liu T, Zhou X, Li Z, . Effects of liquid digestate pretreatment on biogas production for anaerobic digestion of wheat straw. Bioresour Technol, 2019, 280: 345-351.

[37] Mahjoub O, Jemai A, Haddaoui I. Negm AM, Shareef N. Waste management in Tunisia—what could the past bring to the future?. Waste management in MENA regions, 2020, Cham: Springer International Publishing, 35-69.

[38] Makan A, Assobhei O, Mountadar M. Effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco. Iran J Environ Health Sci Eng, 2013, 10: 3.

[39] Markfoged R, Nielsen LP, Nyord T, . Transient N₂O accumulation and emission caused by O₂ depletion in soil after liquid manure injection. Eur J Soil Sci, 2011, 62: 541-550.

[40] Meylan G, Lai A, Hensley J, . Solid waste management of small island developing states—the case of the Seychelles: a systemic and collaborative study of Swiss and Seychellois students to support policy. Environ Sci Pollut Res, 2018, 25: 35791-35804.

[41] Sánchez-Rodríguez AR, Carswell AM, Shaw R, . Advanced processing of food waste based digestate for mitigating nitrogen losses in a winter wheat crop. Front Sustain Food Syst, 2018

[42] Sangamithirai KM, Jayapriya J, Hema J, Manoj R. Evaluation of in-vessel co-composting of yard waste and development of kinetic models for co-composting. Int J Recycl Org Waste Agric, 2015, 4: 157-165.

[43] Stoknes K, Scholwin F, Krzesiński W, . Efficiency of a novel “Food to waste to food” system including anaerobic digestion of food waste and cultivation of vegetables on digestate in a bubble-insulated greenhouse. Waste Manag, 2016, 56: 466-476.

[44] Tibu C, Annang TY, Solomon N, Yirenya-Tawiah D. Effect of the composting process on physicochemical properties and concentration of heavy metals in market waste with additive materials in the Ga West Municipality, Ghana. Int J Recycl Org Waste Agric, 2019, 8: 393-403.

[45] Torres-Climent A, Martin-Mata J, Marhuenda-Egea F, . Composting of the solid phase of digestate from biogas production: optimization of the moisture, C/N ratio, and pH conditions. Commun Soil Sci Plant Anal, 2015, 46: 197-207.

[46] Wang H, Wang D, Zhou X. Analysis on the trend of water quality in Haihe River Basin from 2005 to 2017. GEP, 2018, 06: 1-7.

[47] Xu Z, Li G, Huda N, . Effects of moisture and carbon/nitrogen ratio on gaseous emissions and maturity during direct composting of cornstalks used for filtration of anaerobically digested manure centrate. Bioresour Technol, 2020, 298: 122503.

[48] Zakarya IA, Khalib SNB, Mohd Ramzi N. Effect of pH, temperature and moisture content during composting of rice straw burning at different temperature with food waste and effective microorganisms. E3S Web Conf, 2018, 34: 02019.

Funding

Universität Rostock(funding code: 01DH17063A)

Projekt DEAL