Alla artiklar

A simple model for calculation of nitrogen transports and the effect of wetlands on nitrogen retention is presented. Model input data were taken from an inventory of potential wetlands in the county of Halland (Wessling 1991, Wessling and Skage 1991). Nitrogen retention was calculated according to a relationship between areal nitrogen load and areal nitrogen […]

Full scale tests with nitrogen removal have been performed at the Klagshamn wastewater treatment plant in Malmö, Sweden. Characterization of the wastewater and earlier tests at the plant have shown that the organic material in the primary effluent was limiting the overall nitrogen removal. The organic material in the raw wastewater measured as BOD7 was […]

P removal and chlorination of artificial wastewaters by electrocoagulation – flotation and Cl2 generation were investigated. The Cl2 generation by carbon electrodes and the Al generation by Al electrodes, employing alternating current, were combined into a recirculation system.

Phosphorus and nitrogen mass balances for Lake Vänern show that ca 70 % of the total phosphorus input accumulates in the sediments, while 25 to 40 % of the total nitrogen input was lost via sedimentation and denitrification. These results are based on total input calculations for the period 1970 to 1989, and transport via […]

At GRYAAB’s wastewater treatment plant, Ryaverket, in Gothenburg, pilot plant investigations are being performed for evaluating technologies which can be used to meet anticipated demands for 50 % nitrogen removal. Two alternatives are being investigated. One alternative uses pre-denitrifiction in the activated sludge process. Preliminary results show that this is a functional but expensive alternative […]

Nitrogen removal by biological denitrification is a well-known process. Several processes in full scale are operating in Scandinavia. The process alternatives are described on the basis of biomass composition, process lay-out, and special contractor design. The systems described includes biological filters, seperate sludge systems, and combined sludge systems. Combined sludge is the most common system […]

This article discusses the main issues of the Gouvernment’s latest proposition called ”a satisfactory environment for living”. Discharge of nitrogen from antropogenic sources, especially from sewage treatment plants on the coast, is discussed. The National Swedish Environmental Protection Board, SNV, has claimed that 70 major sewage plants ought to be extended with efficient nitrogen removal […]

Aspects of the selection of filters for the determination of suspended solids in effluents and natural waters are discussed. Different brands of glass fibre filters and polycarbonate filters are compared. No single filter can be standardized for the determination of suspended solids. The choice of filter depends on the measurement in question and on the […]

The process is here called ”Simultaneous Denitrification” though intensive treatment with activated sludge is concerned and biological removal of both nitrogen and phosphorus is obtained. However, nowadays nitrogen removal is more interesting, as phosphorus removal is possible by several methods. The process has no specific aeration or anoxic zones. Nitrification is intensive, primarily because of […]

Water resources management in Germany is based on river basin related planning and discharge fees respectively. Large amounts of data are processed in the planning, that is describing and analyzing, emphasizing on solving conflicts between water users (including the natural ecosystem). Management is more connected with the fees that are taken out mainly on the […]