1993-2

Dephosphatation in sewage has reduced the P-loading on the recipients, but has at the same time resulted in an accumulation of P in urban regions. Will this accumulation with time give rise to increased pollution from non-point sources of P? In order to quantify the P turnover in urban regions, a P-balance has been calculated […]

Fågelmyran municipal landfill site, situated some ten kilometers north of Borlänge, Sweden, is run by Borlänge Energi AB. Leachate generated at the landfill is conveyed to the municipal wastewater treatment plant. Treatment is costly, inefficient and may affect the sludge quality negatively. Borlänge Energi decided to investigate the treatability of the water using existing facilities […]

Water samples were taken during the ice-free period in 1991 from Isojoki river in southwestern Finland to study seasonal and local variations of the water chemistry of the river. In this paper we have especially concentrated on acidification problems and buffer properties of the river water. Except measurements of pH, alkalinity and other parameters, buffer […]

Natural humic water was treated with simulated sunlight (310-800 nm) and the effects on some chemical parameters and the molecular size distribution of the dissolved organic matter were recorded. The dissolved organic carbon content, the light absorbance (254 nm), and the colour were found to decrease substantially already after irradiation for 24 hours. The proportion […]

Mechanical and biological wastewater treatment was evaluated in a full scale test during the 1991-92 Wasa base expedition period. The base was erected on a nunatakk in the Norwegian Antarctic sector and housed 10-20 people. The results indicated that wastewater organics were reduced by a total of 70 %. Small changes in other constituents were […]

A bloom of Prymnesium parvum Carter (Prymnesiophyceae) caused a considerable fish death in the Bay of Holminge, ca 12 km NO Stockholm, Sweden, during May and June 1991. The bay is a shallow coastal lake, influenced by brackish water from the Baltic Sea (Kyrkfjärden). During spring 1992 Prymnesium also invaded the Kyrkfjärden area. A maximum […]

In the wastewater plant at Särdal a biological treatment of phosphorus and nitrogen has been working successfully since 1990. At optimal conditions in spring and autumn of 1991 and 1992 the discharges were 0.3 mg/l of phosphorus and 6 mg/l of nitrogen. The removal of phosphorus was 93 % and of nitrogen 78 %. Summer […]

From February to April in 1992, oxygen gas was introduced in one of six aeration basins at the Slottshagen waste water treatment plant in Norrköping, Sweden. During this period the nitrification activity is usually very low and the oxygen levels in a large part of the aeration basins are below 1 mg/l. As oxygen was […]