| Abstrakt: |
The protozoan fauna of an activated sludge developing in a small scale pilot plant has been studied. A definite sequence of protozoa: - flagellates, free-swimming ciliates, crawling hypotrichs and attached peritrichs, has been observed and described. The crawling hypotrichs Aspidisca costata and Aspidisca lynceus have been shown to hold an inverse relationship with the peritrichous ciliates. The sequence of ciliates in a developing activated sludge indicates that the sludge proceeds, from a condition allied to the polysaprobic condition of a heavily polluted river, towards the oligosaprobic condition. Reasons for the occurrence of such successions are suggested, and the limitations of using ciliated protozoa as indicator species in sewage treatment processes are discussed. [ABSTRACT FROM AUTHOR] |
