To provide a means to prevent dried sludge from raising temperature due to the oxidative reaction of an iron component contained in digestion sludge, in drying the digestion sludge taken out from a methane fermentor to make it dried sludge, in an anaerobic treatment in which the methane fermentation of organic waste loaded with an inorganic flocculant containing iron as a component, or organic waste essentially high in iron content is carried out in the methane fermentor.
The digestion sludge 7 is taken out from the methane fermentor 32, and is stored in a sludge storage chamber 34, and the aeration is carried out for the digestion sludge 7 in the sludge storage chamber 34, by which the iron component in the sludge, reduced in the methane fermentor 32, is oxidized in the sludge storage chamber 34, and the iron component is not oxidized at all in the subsequent sludge utilization process and product.
NEDACHI OSAMU
ABE TAKESHI
KOMURO JUNICHI
Yoshihiro Morimoto