The operation of three storm standby tanks contiguous to an intercepting sewer which serves both combined sewers and sanitary sewers was investigated to determine the effectiveness of the tanks in improving the quality of the waste water prior to its discharge into the river. Based on influent and effluent sampling data collected during the study period, storm standby tank facilities reduce significantly concentration of the solids and B.O.D. in the waste water in storm runoff periods. The extent of reduction is dependent to a major degree on the detention time of flow passing through the tanks. Improvement of dissolved oxygen resulting from passage of waste water through the tanks is very substantial, especially during periods when the dissolved oxygen content of the influent is low.

Diatoms comprise the major group of algae in Iowa waters. Their ecological significance, important in pollution evaluation studies, cannot be fully appreciated without a thorough knowledge of their taxonomy. A scale for abundance rating was used giving at least a rough estimate if data permitted. The names of 50 diatom genera occurring in Iowa are listed and for each genus, the number of taxa in the master list and the number in the 'more common' list are presented. A pollen analysis is tabulated; the samples in this analysis extended through 35 ft. of sediment to the postglacial interface at Little Miller's Bay, Lake West Okoboji. Dating was conducted by the radiocarbon technique for samples taken between 34 ft. and 35 ft. in the sediment core. Since this level had the maximum spruce pollen concentration and the pollen percentage decreased progressively above this level, it was considered as the postglacial interface. Some interesting problems lie in consideration of those diatoms which have disappeared from the original lake flora and those which have become common only since the middle of the postglacial period.

A survey of 452 eutrophic lakes was compiled based on responses from 40 states requesting information as to (a) Name, location, size, depth; (b) Description of the problem, including accounts of previous corrective treatments, if any; (c) Remedial action that might be appropriate; (d) A description of available background data, indicating whether sufficient data exists to document a change if rehabilitation were undertaken. Categories of the problems in the survey were: nuisance algal growth, nuisance aquatic vegetation, fishkills, bacterial contamination, toxic contamination, oil brines, unstable water levels, siltation, excessive dissolved solids, and unspecified eutrophic conditions. Sources contributing to these problems were classified in two general categories--concentrated sources and diffused sources. Indication is given, where available, whether progress has been made to eliminate the pollution source.

The introduction of microorganisms with specific degradative capacities into the soil was shown to be a possible means of ridding the soil of contaminating chemicals. An investigation of the interactions of soil microorganisms and several groups of herbicidal compounds, primarily chlorinated derivatives, was made. In pure culture and in soils the addition of 2,3,5,6-tetrachloroterephthalate (DCPA) had little effect upon bacterial growth, and several microorganisms appeared to use the herbicide as a carbon source. The encouragement of the soil microflora by the addition of nutrient broths resulted in a reduction of toxicity to plants of a number of herbicides. Isopropyl N-phenylcarbamate (IPC) degrading organisms, when added to soil, accelerated the degradation of IPC and related compounds. A membrane 'biologicalilter' device for reducing waterborne biodegradable pollutants was also demonstrated using these organisms.