1989-2

The mathematic models used for trickling filter design today do not give a correct picture of the influence of depth on the process efficiency. The effect of an increased filter depth is overestimated, resulting in an uneconomical design. The design models used are normally based on a first order reaction equation and the most common […]

The concentrations of cadmium and lead in water from 280 private wells were determined. The aim of the study was to elucidate if the presence of these metals is a health problem when the water is used as drinking water. The water in many Swedish wells is very acid and is also influenced by the […]

The aim of this paper has been to discuss some results and experiences that may be drawn from the project »Environment/Cellulose l», sponsored by the National Swedish Environmental Protection Board. The emissions from pulp bleacheries consist of many complex substances, some of which are identified (like dioxins and chlorophenols), most of which are unknown in […]

The aim of the present study was to determine the pollution load originating from storm water on Lake Växjösjön. Each year about 1,050,000 m3 of storm water are discharged into the lake. Storm water represents a substantial pollution source for the lake and therefore also a main reason for the hypertrophic conditions in the lake. […]

Dosing is a common unit operation in water and sewage treatment technology. In that connection it is important to choose reliable and accurate equipment. The article describes different automatical dosing systems, different dosing pumps and claims given when selecting dosing systems. It is also important to design the installation in the right way. Examples for […]

Long-term ice-cover occurring on high-mountain and subarctic lakes as well as on brackish-water seas such as the Gulf of Bothnia promotes certain algae species, well adapted to low-light and low-temperature and/ or heterotrophic nutrition. Such algal species often belong to the dinoflagellates. In the northern Bothnian Sea, as in Lake Torneträsk, dinoflagellates are predominant under […]