Suchergebnisse

ABSTRACTThis paper presents the results of a series of load tests carried out on a variety of designs of boundary boxes which are intended for use as stopcock/water meter chanbers at domestic properties. A description is given of a test which has been developed at Loughborough University to measure the performance, under load, of the complete boundary‐box units in simulated site conditions. Three broad classifications of different design types are identified, namely rigid, flexible and sliding; and the load displacement characteristics of each type are presented and discussed. The effects of rate of loading and different backfill conditions are considered, and conclusions are drawn on suitable performance specifications under load.

ABSTRACTAn investigation is reported into the effect of pressures of up to 6 bar on the operation of a laboratory‐scale rotating biological contactor. All results are compared with those of an identical reactor operating at atmospheric pressure. Few previous results relating to the effect of pressure on biological wastewater treatment could be found in the literature. Although improved BOD and COD removal (compared to that of the reference unit) was evident as the pressure was increased, the principal benefits of increasing pressure were recorded as being (a) significantly improved nitrification, and (b) a decrease in the sludge yield coefficient. Both these factors improved regularly with increasing pressure, although there is some indication that the production of total oxidized nitrogen might have been affected at the highest pressure employed.