Spent Mushroom Substrate as a Supplementary Material for Sewage Sludge Composting Mixtures

Abstract

Zużyte podłoże popieczarkowe jako materiał pomocniczy do przygotowywania mieszanek kompostowych z osadów ściekowych Spent mushroom substrate (SMS) is a byproduct from mushroom production. On average, it shows low content of organic matter but contains relatively high quantity of nitrogen (2.4%). SMS could be recycled as a soil amendment or could be an alternative for peat. Some studies indicate that SMS could be used as a supplementary material in composting of various biodegradable waste and municipal sewage sludge (SS). In composting, spent mushroom substrate could function as a bulking agent and provide structure in composting piles. The overall goal of this study was to determine whether SMS can be used as a supplementary material for preparation of composting mixtures of sewage sludge and could allow the achievement of the recommended values of moisture content (50÷60%), C/N ratio (25-35:1) and air-filled porosity (at least 75%) in the final composting mixtures. Due to high moisture content, low C/N ratio and lack of structure municipal sewage sludge cannot be composted alone. The addition of a supplementary material to municipal sewage sludge should provide adequate structure (for maintaining optimal air-filled porosity in a composting pile), moisture content and C/N ratio in the composting mixtures. The investigated SMS showed lower moisture content, organic matter, C/N ratio and mechanical strength in comparison to typical supplementary materials used in composting of sewage sludge (e.g. wheat straw or woodchips). The addition of SMS to SS (up to the ratio of SS:SMS 1:6) did not allow the achievement of the recommended values of moisture content, C/N ratio and air-filled porosity within a 2 m composting pile. Therefore, the investigated spent mushroom substrate cannot be considered a suitable bulking agent for preparation of municipal sewage sludge composting mixtures. However, SMS could be used for composting of other biodegradable waste which shows lower moisture content, higher C/N and better structure or for composting of sewage sludge together with lower quantities of other supplementary materials such as wheat straw.

Effects of Application of Recycled Chicken Manure and Spent Mushroom Substrate on Organic Matter, Acidity, and Hydraulic Properties of Sandy Soils

“…two units. This is attributed to the alkaline reaction (pH > 7) of both organic materials (e.g., [ 24 , 25 ]. Therefore, raising the pH of the studied acidic soils has a beneficial effect on soil quality and crop production and contributes to reduction of the use of new carbonate rocks to neutralize soil acidity [ 59 ].…”

“…The utilisation of poultry (chicken) manure from waste disposal and spent mushroom substrate (SMS) remaining after harvesting mushrooms is widely recommended for beneficial recycling in agriculture to obtain completely natural nutrient and organic carbon cycles and to pursue long-term sustainability [ 21 , 22 ]. Both organic materials are valuable components of composts [ 22 , 23 , 24 ]. Due to their alkaline reactions, the materials can diminish soil acidity [ 24 , 25 ] and enhance nutrient availability [ 26 ].…”

“…Both organic materials are valuable components of composts [ 22 , 23 , 24 ]. Due to their alkaline reactions, the materials can diminish soil acidity [ 24 , 25 ] and enhance nutrient availability [ 26 ]. Moreover, poultry manure and litter are a source of chemical energy for electricity and heat generation [ 27 , 28 ], and SMS is used as a substrate for other mushroom-forming fungi and in the production of biofuels and enzymes [ 21 ].…”

Image Analysis of Sewage Sludge and Barley Straw as Biological Materials Composted under Different Conditions

“…An example is municipal sewage sludge [5,6,7,8]. Unfortunately, due to the amorphous structure and unfavorable chemical composition (excess of nitrogen in relation to carbon), the use of sewage sludge as the only substrate for composting is not rational [9,10]. Therefore, it is mixed with other substrates that loosen the structure and at the same time improve the carbon (C) to nitrogen (N) ratio [11,12].…”

“…As a result, composting, next to the combustion process, will become one of the two most important methods of this type of waste management. This fact has made it possible to observe recently increased research activity in the field of sewage sludge composting [9,15,16,17,18,19,20], related to both recognizing these processes and their optimization in terms of minimizing the time needed to obtain a final product with adequate quality. The research on composting of municipal sewage sludge is most often carried out on a laboratory scale.…”