1992-1

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 […]

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 […]

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 […]

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.

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 […]

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 […]

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 […]

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 […]

Most climatologists recognize that emissions of carbon dioxide, methane, and other so called greenhouse gases will result in a gradually increasing mean global temperature. The increase in temperature will, in turn, lead to rising sea levels, caused by thermal expansion of the oceans and melting of arctic and antarctic ice caps. According to researchers, a […]

The flow of water which leaks in through sewer manhole covers was estimated by experiments. During storms or periods of snow-melt, the volume of water leaking in through these manholes may increase the flow in the sewers substantially, resulting in an increased risk of secondary damage. The variations in water flow leaking through the key-holes […]

Open low-loaded filter basins with drains is one example of biological methods for sewage treatment. Results from two new units, in operation since 1991, show a 95 %-reduction of total-P and BOD7 during the summer. The reduction is less during vintertime, due to lower biological activity in the filter. A study of this type of […]

Det danska dataprogrammet EFOR för simulering av de dynamiska processerna i en aktivslamanläggning tillgängligt i svensk översättning. I programmet efterliknas driften av ett reningsverk, och driftparametrar och driftresultat kan beräknas. Effekterna av ändrade drift- och belastningsförhållanden kan således förutses med programmets hjälp. Programmet är ett redskap, som kan användas för såväl driftoptimering som för analyser […]

The quality of drinking water must be monitored continuously. Before a raw water supply is taken into use its quality must be checked very carefully, and more detailed examinations must then be made at later stages, e.g. after five years. The larger examinations in effect form a continuous monitoring programme and can reveal some astonishing […]