摘要：A survey was made of organic pollution in the rivers of the Osaka City area during the last decade. Despite the decrease in carbonaceous BOD, there was little improvement in BOD overall due to an increase in nitrogenous BOD. The nitrogenous BOD/BOD ratio has increased because of the inflow of sewage treatment water rich in nitrogen compounds. The mechanism of nitrification has however not been elucidated. COD has improved but ubiquitous pollution was indicated even in sites with low BOD. Suspended solids were little related to organic pollution.
