Composting is a bioxidative process leading to a higly stabilized organic product, which may then contribute directly to soil conditioning and fertility. Compared to other processes (fermentation or anaerobiosis ) , composting allows a fast, simple and safe approach to bulk treatment of organic wastes. It also produces less odour, and develops a thermophilic stage which decreases the concentration of animal and plant pathogens in the mass. On the other hand, fermentation and anaerobiosis lead to products which will undergo further stabilization (bioxidation) when exposed to air. For industrial composting of organic residues, maximum process efficiency is required, which in turn is a reflection of our capability to manage the microbial population growth and activity. Main factors which need to be optimized are: oxygen supply to the mass, moisture and temperature control, C/K ratio, balance of nutrients and pH. Also, fast diffusion and a proper succession of microbial populations, as separately required in the different stages, are most essential. Generally, substratum composition {carbon, nutrients, pH, moisture) and therefore microbial metabolism tend to become limiting factors when processing urban, agricultural and industrial waste. Process programming and plant design must then take into account the specific limitations in dealing with different organic materials. Management of the process of composting must take into account the end-product value and compatibility with plant cultivation. Production of phytotoxic metabolites characterizes the intermediate phases of organic matter degradation and may be used as a parameter to assess the degree of stabilization of the process. Use of organic soil conditioners in agriculture, may then involve different products in relation to the degree of stabilization, according to specificneeds as well as considerations on costs and energy conservation.
Technological aspects of composting including modelling and microbiology
VALLINI, Giovanni;
1985-01-01
Abstract
Composting is a bioxidative process leading to a higly stabilized organic product, which may then contribute directly to soil conditioning and fertility. Compared to other processes (fermentation or anaerobiosis ) , composting allows a fast, simple and safe approach to bulk treatment of organic wastes. It also produces less odour, and develops a thermophilic stage which decreases the concentration of animal and plant pathogens in the mass. On the other hand, fermentation and anaerobiosis lead to products which will undergo further stabilization (bioxidation) when exposed to air. For industrial composting of organic residues, maximum process efficiency is required, which in turn is a reflection of our capability to manage the microbial population growth and activity. Main factors which need to be optimized are: oxygen supply to the mass, moisture and temperature control, C/K ratio, balance of nutrients and pH. Also, fast diffusion and a proper succession of microbial populations, as separately required in the different stages, are most essential. Generally, substratum composition {carbon, nutrients, pH, moisture) and therefore microbial metabolism tend to become limiting factors when processing urban, agricultural and industrial waste. Process programming and plant design must then take into account the specific limitations in dealing with different organic materials. Management of the process of composting must take into account the end-product value and compatibility with plant cultivation. Production of phytotoxic metabolites characterizes the intermediate phases of organic matter degradation and may be used as a parameter to assess the degree of stabilization of the process. Use of organic soil conditioners in agriculture, may then involve different products in relation to the degree of stabilization, according to specificneeds as well as considerations on costs and energy conservation.
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