Ecological Studies on Percolating Filters and Stream Riffles Associated with the Disposal of Domestic and Industrial Wastes

: This thesis consists of 2 volumes

Abstract

The literature concerning stream riffle, percolating filter and invertebrate toxicity studies is reviewed.

The film, micro-organisms and grazer populations were investigated at two sewage treatment works, one of which, Gospel End, treated domestic sewage and the other, Roundhill, a mixed domestic and industrial sewage. Extensive film accumulation at Roundhill, caused by high-frequency dosing, was unfavourable to extensive protozoan and grazer colonization. At Gospel End, where dosing frequency was variable, protozoan, nematode and grazer populations prevented film accumulation. Chironomids were more important in restricting film growth during the warmer months and psychodids during the winter. The density of the microfauna was also affected by the activities of the grazers. Twice as many protozoan species were found at Gospel End as at Roundhill.

The benthic fauna of the River Stour and its tributaries was investigated over a period of six years. The River Stour was found to be polluted by organic and toxic pollutants throughout the stretch from Halesowen downstream. ‘Tributaries draining the south of the area were generally clean, whereas most of those draining the industrialised northern parts were usually badly polluted. Tubificids, enchytraeids and. Limnaea pereger were the most abundant species found in organically polluted waters. In streams subject to discharges containing heavy metals, tubificids, encnytraeids and sometimes chironomids and Asellus were the commonest species. Improvement of the effluents from the two works studied led to improvements in the receiving watercourses. The Chandler Score was found to be the most applicable of the biotic indices considered. In toxicity tests, Asellus aquaticus was the most tolerant of the test species to zinc at different temperatures, hardness and dissolved oxygen values. When dissolved oxygen concentration was high, Baetis rhodani was more tolerant than either Gammarus pulex or Limnaea pereger. Linnaea was generally intolerant to zine.

Date of Award	May 1975
Original language	English
Awarding Institution	Aston University