1987-4

Raw water, treated water and distributed water from three water works in the vicinity of Oslo, Norway, were investigated for content of heterotrophic, aerobic microorganisms and total count of bacteria. The treatment was different in the three water works, but they all got raw water from the hypolimnion of stratified lakes. The total counts were […]

The past decade’s chemical, toxicological and epidemiological research on by-products of drinking water chlorination has been reviewed. A large number of by-products has been identified and tested in different bioassays, and, recently, considerable progress has been made in the identification of Ames mutagenic byproducts. Still, there is little hope that the present uncertainty of chemical-toxicological […]

Today there is a serious concern about the consequences of a global climate change. One possible effect of this change is a considerable rise of the sea level. According to several prognoses it may be expected that the sea level rise by the year 2100 may lie between 0.9 and 1.7 m with a preferred […]

Earlier investigations have shown that the run-off from a forested area increases after clear-cutting. For Swedish conditions, values between 90 and 406 mm/year have been reported. On the bases of micrometeorological measurements above clearcut and forest areas and of theoretical discussions, light can be shed on the causes to the run-off increase. The present micro-meteorological […]

Systematic recordings of alkalinity may give early warning of change in acidification status. Fixed endpoint titration is a method well suited for routine measurements. But, standardized procedures for alkalinity titration do not take into account errors in endpoint pH caused by stirring of the samples. The magnitude of this effect depends on individual and variable […]

The intention with the trial operation at the sewage treatment plant Västra Stranden, Halmstad was to investigate what the nitrogen removal would be during summer conditions after extension of the tanks for anoxic pre-denitrification to the double. The flow to the three separate activated sludge units was distributed in such a way that two of […]

New process technologies have considerably improved the specific nitrification capacity per unit area of immersion percolating filters. The operating principle is based on strict separation of the carbon reduction and nitrification processes together with uniform substratum supplies in cascade plants. These processes lake the immersion percolating filter viable even for high capacity plants. The method […]