DIKVÄVEOXIDPRODUKTION OCH EMISSION FRÅN VÅTMARKER, Nitrous Oxide Production and Emission
The concentration of nitrous oxide in the atmosphere increases with 0.25 % per year. Nitrous oxide degrades ozone and it also increases the green-house effect. Many biological processes can produce nitrous oxide. The three most important processes are nitrification, denitrification and dissimilatory ammonium production. These biological processes are of importance in development of systems for […]
NÄRSALTSRENING MED VATTENVÄXTER – SLUTRAPPORT FRÅN SNOGERÖDSPROJEKTET / Reduction of Nutrients by Water Plants – Final Report the Snogeröd Project
From September 1988 up to June 1991 a full-scale experiment was conducted using a submerged macrophyte pond and a root-zone for wastewater treatment. The mean removal was 32 % and 46 % of nitrogen and 62 % and 61 % of phosphorus respectively. The major removal mechanism for N was denitrification and for P assimilation, […]
KVÄVEBUDGET FÖR BJÖRKAREN – EN IGENVÄXT SJÖ I NORRTÄLJE KOMMUN /Nitrogen Budget for Lake Björkaren, a Shallow Lake in Southern Sweden
The role of wetlands, ponds and lakes in the retention of nitrogen and thus in the decrease of nitrogen transport to the sea is under discussion in Sweden. In this paper nitrogen budgets for Lake Björkaren during four years are presented. The lake is very shallow and almost covered with higher vegetation and the water […]
RETENTION OR LOSS OF NITROGEN IN FOREST WETLANDS
There are diverging opinions on nitrogen retention in wetlands. In southern Sweden, wetlands contribute to limit nitrogen leaching. In forest wetlands in central and northern Sweden there are only indications on small or no retention effects. Wetland types as well as the nitrogen load vary. Outflow of nitrogen from forested watersheds, including considerable wetland areas, […]
VÅTMARKSHYDROLOGI – Några frågor kring flöden och vattenomsättning / The Hydrology of Wetlands – Some Questions Concerning the Flows and Turnover of Water
The creation and restoration of wetlands has been suggested as an efficient method for the reduction of the transport of nitrogen to the Swedish coastal waters. In the paper, which is written from a hydrological viewpoint, a few critical questions are identified which require further clarification. The questions concern our knowledge about retention processes, dynamics […]
FYRISÅNS AVRINNINGSOMRÅDE KLASSAT FRÅN SATELLITDATA OCH DIGITAL KARTDATA / The Catchment Area of River Fyrisån Classified from Satellite Data and Digital Map Data
There are several ways to obtain information about land use and vegetation for an area. In this project we have used satellite images to calculate statistics for the drainage area of River Fyrisån in Uppland, Sweden. A Landsat TM (Thematic mapper) image registered on the 7th of July, 1989 was used. The spectral information in […]
VÅTMARKER SOM KVÄVEFÄLLA – mot en planeringsmodell för restaurering av våtmarker / Wetlands as Nitrogen Sinks – Towards a Model for Planning of Wetland Restoration
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 […]
NITROGEN REMOVAL IN AN ACTIVATED SLUDGE SYSTEM WITHOUT PRIMARY CLARIFICATION
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 […]
PHOSPHORUS REMOVAL AND CHLORINATION OF WASTEWATERS BY ELECTROLYSIS
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.
MATERIALBALANSER FÖR VÄNERNS FOSFOR- OCH KVÄVETRANSPORTER 1970-1989 / Nitrogen and Phosphorus Mass Balances for Lake Vänern 1970-1989
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 […]