1993-4

The Klagshamn wastewater treatment plant is operated with extended BOD, phosphorus and nitrogen removal. A high and stable removal of nitrogen is reached with a process configuration based on pre-precipitation and the use of an external carbon source in a single sludge post-denitrification process. The detention time in the bioreactor is about 7 hours. The […]

Experiments were carried out at Bromma wastewater treatment plant with nitrification of reject water using SBR technics (Sequencing Batch Reactor). The studies were performed mainly in a pilot plant scale, but some complementary tests were done in a laboratory scale. The purpose was to give a basis for estimation of an appropriate oxygen concentration and […]

In water with high levels of nitrogen, it can be of interest to use reverse osmosis for removal of the nitrogen. This can help to reduce the total load of the wastewater treatment plant. To improve removal of nitrogen, high pressure can be used to press the nitrogen-water through a reverse osmosis membrane. The nitrogen […]

Sewage sludge is in most cases not accepted as a fertilizer in agriculture. The reason is a concern for eventual environmental effects due to the presence of environmentally hazardous substances in sludge. Use of sludge in agriculture will not lead to environmental effects. A risk analysis shows this. Consequently, there are no environmentally hazardous substances […]

The Pyranine 120 % colourant is chemically the sodium salt of 3-oxypyrenetrisulphonic acid. It is used to colour district heating water when seaking leaks into warm domestic water supplies. It colours the water a fluorescent yellowish green, and small amounts can be detected either by UV light or spectrophotometrically. It is not detrimental to health.

Chlorine dioxide is a highly effective oxidising agent with powerful deodorising and bleaching properties. Its action on pathogenic micro-organisms is stronger than that of chlorine. A major drawback has, until now, been that chlorine dioxide invariably must be produced on the spot by reacting chlorine or hydrochloric acid in solution with sodium chlorite. A stable […]

At the Ringsjö plant, laboratory and pilot scale tests has been carried out with a process for water treatment where the conventional process coagulation-flocculation-sedimentation is accelerated by dosing of microsand in the flocculation step. The microsand improves the sedimentation velocity of the flocs formed, while at the same time reducing the flocculation time needed. The […]