Insect Life on Sewage Filters

Abstract

THE title of this little book is rather misleading. The original matter deals almost entirely with one species of insect, Achorutes viaticus, in relation to the efficiency of the sewage filters where it is very frequently found in large numbers. The authors seek to prove that Achorutes attack and consume the colloidal matter and fungoid growths which often choke the upper layers of the filters, and in this way enable a larger volume of sewage to be purified than is possible when these insects are not present. Experiments were made with I two filters; in one precautions were taken to exclude Achorutes; in the other the insects were encouraged to develop. Analyses of the effluents produced by these filters showed that where Achorutes was absent the purification effected was less than in the other filter, but when the insects were added to the first filter nitrification improved at once. Although the authors' conclusion seems to be justified, their interesting experiment is scarcely worthy of publication in book form. The biological details appear to be mostly from Haig Johnson's work on the subject.