Alla artiklar

Today the west coast of Sweden can be flooded at a combination of strong winds from west and low pressures. In a future with climatic change and increasing precipitation and raising sea-levels a considerable increase of flood occasions can be expected. The consultant VBB VIAK has together with the municipalities of Göteborg, Kungsbacka and Halmstad […]

This article reports on the first part of a study of biological and chemical processes in a sewer network and discusses the requirements for the biological decomposition of organic material. The consequences of smoothing flow variations, which is preferred by the sewage treatment plant, are considered. This study shows that it is theoretically possible to […]

Could future sharper demands for phosphorus removal at the wastewater treatment plants be met with a broad change-over to washing-agents without phosphorus? A full scale experiment has been conducted at the wastewater treatment plant Dagsberg in the community of Norrköping. At this plant phosphorus is removed through coagulation with ferric chloride. The water consumers in […]

P removal and chlorination of artificial wastewater were examined by a continuous flow system. The ability of an electrolyser with carbon electrodes in adjusting pH, together with free chlorine generation, was tested. Interesting results concerning the energy consumption have been described.

During the autumn of 1991 laboratory tests and pilot plant studies were carried out at LTH and Sjölunda sewage treatment plant in Malmö. The aim was to investigate the influence of secondary release of phosphate in biological phosphorus removal systems. Secondary release of phosphate was observed under aerobic conditions both in the laboratory tests and […]

Supernatant liquid from digesting tanks is rich in ammonia. Treatment of supernatant liquid by stripping and absorption was investigated technically and economically under Danish conditions. In a pilot plant, 50 % of the ammonia was removed in one tower. The ammonia was absorbed in sulphuric acid whereby ammonium sulphate was formed. Technical and economical assessments […]

För att uppnå bättre vattenkvalitet i Laholmsbukten har bl a Halmstads kommun ålagts att under de närmaste åren genomföra miljöförbättrande åtgärder i kommunens avloppsanläggningar, främst inriktade på kvävereduktion, vid tre större avloppsreningsverk. Målet är att minska kväveutsläppen från ca 300 ton/år till ca 120 ton/år. Beräknad kostnad är ca 100 milj kr. Trots denna mycket […]

Trial operation with biological nitrogen removal was started up on July 1, 1989, in an extended activated sludge line at the sewage treatment plant Västra Stranden in Halmstad with financial support of ”New Technics” by Swedish Environmental Protection Agency. The possibilities to increase the nitrogen removal as well as the phosphorus removal have been investigated […]

Benthos from lakes and running waters has been used to assess the extent of surface water acidification in Sweden 1969-1991. Altogether 2,861 different waters have been investigated. The acidification status was determined by classifying the different taxa into two groups – acid sensitive, i.e. do not tolerate pH below 5.5 and acid tolerant, i.e. tolerate […]

Current practice in Swedish environmental policy treats most acid surface waters as likely cases of acidification resulting from acid deposition that are suitable objects for liming. That approach to the management of acidity in surface waters is based largely on the understanding of surface water acidification in the clear water lakes and streams of southern […]