BLUE MUSSEL SEA FARMING – EFFECTS ON WATER QUALITY
Water currents through a blue-mussel culture have been studied together with inorganic nutrients, oxygen, salinity and temperature. A hanging long-line culture of Mytilus edulis L. was followed from June 1978 to March 1980. There were considerable changes in all parameters during the farming period. These changes were to some extent attributable to the seasonal cycle. […]
MAY RETENTION BASINS HAVE AN OVERALL NEGATIVE EFFECT?
Mathematical models for sewer networks and for waste water treatment plants are combined to simulate six summer months of actual rainfall in the Oslo area. The sewer network is a combined sewer system. The simulations showed that a retention volume installed at the storm overflow could cause more pollution to escape from the treatment plant […]
MODELLING THE EFFECT OF SEWAGE LOADING AND OCCURRENCE OF MACROPHYTES ON THE OXYGEN CONCENTRATION IN SOME DANISH WATERCOURSES
The stream fauna is among other things dependent on the oxygen content of the water. So in recipient quality planning it is essential for the authorities to be able to investigate the effect of different loading situations on the water. The paper describes an investigation in the Langvad å drainage system in Zealand, Denmark, where […]
BIOLOGISKA DAMMAR SOM POLERINGSSTEG VID RENINGSVERKET I LUND / Oxidation Ponds as Polishing Process at the Wastewater Treatment Plant in Lund
The demands on the Swedish wastewater treatment plants have increased dramatically during the last decades. As a consequence more complicated processes are used today. Also, in order to reduce the capital costs there has been a tendency to use as small process volumes as possible, i.e. the volumetric loads used have increased. Therefore, the treatment […]
TRANSMISSION OF VIRUSES IN PUBLIC SWIMMING POOLS
The evaluation of the possible transmission routes of viral diseases in public swimming pools and their environments demands extension of the hygienic control not only to the swimming water but to the total environments of these facilities. The same clinical syndrome may be caused by several types of viruses and one type of virus may […]
VANDINDVINDINGENS BETYDNING FOR DE ØKOLOGISKE FORHOLD I VANDLØB / The Effect of Reduced Discharge on the Ecology of Streams
Most Danish streams have their discharge reduced due to withdrawal of water for field irrigational purposes. Reduced discharge creates a deteriorated stream environment, that is reduced depth, reduced water velocity, increased sedimentation of oxygen consuming organic substances, reduced reaeration of oxygen, and larger temperature excursions. These factors combined with an improved light regime at the […]
HYDROLOGISK OCH HYDROKEMISK MODELLBERÄKNING I SJÖRIKA SKOGSOMRÅDEN / Hydrological and hydrochemical simulation in basins dominated by forests and lakes
A hydrological model for runoff simulation in basins dominated by forests and lakes has been developed and tested. The results suggest that the dynamics in the runoff record may be reproduced without extensive model calibration provided the damping in the lakes is described explicitly and a division into submodels is made. The volume errors may […]
THE DISSOLUTION EFFICIENCY FOR DIFFERENT STREAM LIMING METHODS AND TECHNOLOGIES
The dissolution efficiency for different stream liming methods can be shown to depend upon a small number of parameters. They are several orders of magnitude more important than other parameters influencing the dissolution efficiency. The parameters are: – Particle size distribution – Initial pH-value– Dose intensity– Degree of wet slurrying The particle size distribution and […]
EFFEKTER AV SMÅBÅTSHAMNAR PÅ DJURLIVET I GRUNDA HAVSOMRÅDEN PÅ SVENSKA VÄSTKUSTEN, / Effects of Small Boat Harbours on the Fauna in Shallow Marine Areas on the West Coast of Sweden
On the Swedish west coast an increased demand for new small boat harbours has often lead to conflicts with the coastal fishery and nature conservationists. In this study the effects of small boat harbours on the mobile epibenthic fauna (shrimps, crabs and small fishes) and infauna (mussels, worms and small crustaceans) were investigated. Quantitative samples […]
TILLFÖRSEL AV PETROGENA KOLVÄTEN (PHC) TILL SALTSJÖN OCH ÖSTRA MÄLAREN I STOCKHOLMS LÄN – EN ÖVERSIKTLIG UPPSKATTNING AV KÄLLOR OCH MÄNGDER / The Input of Petroleum Hydrocarbons(PHC) to Saltsjön and Eastern Mälaren in the Province of Stockholm – An Approximate Estimation of Sources and Quantities
The input of petroleum hydrocarbons (PHC) to the coastal waters in the province of Stockholm has been theoretically estimated to 150-630 tons/year. The main quantity originates from land-based discharges. These are transported to the coastal waters directly from municipal waste water treatment plants (20-60 tons/year) and industries (40-145 tons /year) and indirectly from atmospheric fallout […]