engleski

In-vessel composting of winery solid waste

A laboratory composting was conducted to determine the effect of the continuously enforced aeration on the composting performance. The mixture of grape stalks and grape marc was used as a raw composting material. Initial pH-value of substrate was low thus before the start-up phase of composting the substrate was neutralized with NaHCO3, w(NaHCO3) = 2%. Composting was carried out in a closed thermally insulated column reactor (6.0 dm3) at air flow rate of 0.5 dm3min-1kgVS0-1. Air temperatures at the reactor's inlet and at three levels of composting mass (bottom, middle and top) were closely monitored. The temperature changes, moisture content, pH-value, substrate conversion and C/N ratio in the composting pile during 12 days were investigated. During the composting process the highest temperature was 46°C, pH-value varied between 7.1 and 8.3 and moisture content in composting mass was between 59.1 and 68.7 %. At the end of the process the turnover was 48.1%. Modeling could be a useful tool in understanding, prediction and prevention of problems during composting process. Thus, biodegradation rate of organic fraction in the winery solid waste was simulated using an empirical model. It was found out that the selected model describes aerobic composting fairly well and confirms the hypothesis that the released heat is proportional to the biodegradation process.

adiabatic column reactor; composting; grape marc; grape stalks; process modeling

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