The Special Significance of Certain Peritrichous Ciliate Protozoa in the Aerobic Purification of Sewage

sewage water by land filters that nitrification Was due to microbial activity, and since then an increasing amount of attention has been devoted to the investigation of micro-organisms in relation to sewage purification and to the closely allied processes of soil metabolism. A considerable volume of literature has accumulated on the microbiology of these processes, but there is need for further information on certain aspects, e.g. the aerobic process of sewage purification which has been of considerable interest since the early days of scientific study of sanitation and public health.