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A large numbder of samples of the influent, efHuent and the sludge at the Rya WWTP in Göteborg wasanalyzed for organic Priority Pollutants berween 1984 and 1994. Many Priority Pollutants are not used in Göteborg or used in very small quandties and therefore have not been detected in any of the samples or detected sporadically. […]

The summer of 1994 was unusually hoi in Sweden and this caused high temperatures for the raw water and drinking water in Gothenburg. The temperature exceeded 20°C during several weeks. It is well known that temperature has a strong influence on the microbiological activity, but neither the bacterial counts nor the number of taste and […]

During the coming years, Sweden is planning to supporr the construction of several modern wastewarer treatment planrs in ihe Baltic States (e.g. Estonia), in order to improve the vast eutrophication ofthe coastal areas and the open Baluc Sea. Minor attendon is taken to the environmental impact of the future wasrewater treatment plant. Although, the lack […]

There are rwo basic lake types, holomictic and meromictic. Holomictic lakes have a complete verrical mixing whereas the circulation ofmeromictic lakes is incomplete. Meromictic condiaons may be due to accumulation of e.g. iron compounds m the deep water or intrusion ofsalt water into fi-eshwater lakes. Meromicuc conditions may also occur in deep coastal inlets which […]

Mysterious epidemics among drinking water consumers have been related to mass developments ofporentially toxic blue-green algae (Cyanobacteria) in drinking water reservoirs. Blue-green algae can pass rapid sandfiltraion and activated carbon filtrarion. The blue-green algal toxin microcystin has been detected in drinking water after treatment with rapid sand filtrarion/chlorination; rapid sand filtradon/flocculation and after activated carbon […]

Through a reconstruction during 1991 Oresundsverker i Helsingborg has been upgraded to a treatmentplant for extensive nitrogen and phosphorus removal. In order to run theese biological processes in the right way, it is important to know what parameters affecting the quality of the pretreated waste water. Furthermore it is important to understand the connection between […]

Nitrification and denitrification in activated sludge process will be applied at Kungsängsverket in Uppsala municipality to fulfill future effluent requirements. In order to obtain total nitriflcation, a higher sludge retention time is required than in a conventional activated sludge plant. The highest sludge concentration that can be used is dependent on sludge separation properties and […]

Enhanced biologlcal phosphorus removal (EBPR) was studied at the Suomenoja research station in Finland in cooperation with St Petersburg Water and Wastewater Works. The studied process was a mainstream process designed for 10 m3 h-l wkh anaerobic and aerobic units. EBPR proved to be a stable and reliable method that endures organic volumemc loads up […]

If a high loaded activated sludge process is to be part of a process scheme for nutrient removal anaerobic digestion of the biological sludge has to be considered. However, even when plants are upgraded with a low loaded activated sludge process for nutrient removal anaerobic digestion may be of interest if the energy perspective is […]

This investigation is a result of a cooperation between the County Council, the Municipalities and the County Administration in the County ot Västerbotten, Sweden. The purpose was to study connections between mercury levels in northern pike (Esox Lucius) and environmental factors. Furthermore changes in time were investigated. A classification system, which can be used to […]