Composting of sewage sludge with solid fraction of digested pulp from agricultural biogas plant

Abstract

Abstract. Sewage sludge management is an important element of environmental protection. Composting and anaerobic digestion are the biological conversion methods for sewage sludge management. Mass and volume reduction is a result of a properly composted process. Solid fraction of digested pulp can be use as co-substrate, because it is good structural material. The aim of the study was to determine the possibility of composting sewage sludge with a solid fraction of digestate. The compost mix consisted of 25 kilograms of sewage sludge and 20 kilograms solid fraction of digestate in fresh mass. The experiment was carried out in laboratory conditions. Bioreactors of 165 dm 3 volume were used. The experiment included two stages. Stage I took place in bioreactors and lasted until the cooling phase of the compost was complete. Stage II included compost maturation for a period of eight months (to 287 day of composting). The reduction of mass obtained at the end of Stage I amounted 30.2%. At the end of Stage II, it was 86.7% relative to the initial weight of the compost. The maximum value of temperature was 75.1ºC. Studies have shown that sludge with a solid fraction of digestate can be a suitable substrate for composting with sewage sludge.Abbreviations AD -anaerobic digestion DM -dry matter FM -fresh matter MM -mineral matter OM -organic matter in Total Solids SF -solid fraction of digested pulp SL -sewage sludge

Food Waste Management Using Hermetia Illucens Insect

“…Composting is one of the biological processes (Cerda et al, 2018; Nalepa et al, 2018), just like the biogas production in the anaerobic digestion process (Mustafa et al, 2016). The composting process takes place under the aerobic conditions and is popular in the management of many substrates (Czekała et al, 2018;Żukowska et al, 2019). Building a composting plant is cheaper and easier to run than in the case of an agricultural biogas plant.…”