OLIVE-MILL WASTE-WATER COMPOSTING - MICROBIOLOGICAL ASPECTS

Oxygen consumption, microbial growth, lignin and phenol degradation, u rease, protease and nitrogenase activity were determined during the co mposting of an olive-mill wastewaters (OMW)-wheat straw mixture. Oxyge n consumption, microbial growth and urease activity were greatly enhan ced during the thermophilic phase, reaching their maximum in about thr ee weeks. Casein-hydrolysing protease showed a high initial activity w hich sharply decreased after 2 weeks. At the end of the thermophilic p hase both phenols and lignin were reduced by about 70%. Composting enh anced diazotrophic microflora as indicated by nitrogenase activity whi ch increased at the end of the thermophilic phase. (C) 1997 ISWA.