RÖNNINGESJÖNS TILLFRISKNANDE. RESULTAT EFTER DAG- OCH SJÖVATTENBEHANDLING ÅREN 1981-1987 / Recovery of the Lake Rönningesjön in Täby, Sweden. Results of Storm and Lake Water Treatment over the Years 1981-1987
A fullscale plant applicating the Karl Dunkers’ system for combined treatment of separate storm water and lake water is since 1981 operating in the northern part of the lake Rönningesjön, close to Stockholm. The treatment is executed in three simultaneous steps: 1) flow balancing in tanks floating in the lake, 2) phosphorus removal using Fe […]
RECIPIENTBALANS SÖRMLAND – EN MODELL FÖR BERÄKNING AV FOSFORTRANSPORT I DE SÖRMLÄNDSKA VATTENDRAGEN / A Model for Calculating Phosphorus Transport in the Watercourses of the County of Södermanland, Sweden
The addition of plant nutrients to the sea is today one of the most important environmental problems. It is of the outmost importance that measures taken against such discharges will be as cost effective as possible. A computer based mathematical model is described to calculate the transport of phosphorus to the recipient. The drainage area […]
BERÄKNING AV AVRINNING OCH KVÄVELÄCKAGE FRÅN ETT VATTENDRAG MED OLIKA MARKANVÄNDNING / Modelling of Runoff and Nitrogen Leaching from a Basin with Different Land Use
A conceptual model for simultaneous computation of runoff and inorganic leaching from forests, arable lands and lakes has been developed and tested. The model has been verified against data from the Ekenäs area in the county of Södermanland in SE Sweden. The aim is to develop a model which includes the most important factors controlling […]
ET EKSEMPEL PÅ INTERNATIONALT SAMARBEJDE OM AT BEGRÆNSE TILFØRSLEN AF NÆRINGSSALTE FRA LANDBRUG TIL ØSTERSØOMRÅDET / International Cooperation in Reducing the Discharge of Nutrients from Agriculture to the Baltic Sea Area – An Example
Eutrophication is one of the serious pollution problems in the Baltic Sea Area. The nutrients originate from different sources. Agriculture is one of the important sources. In 1985 The Helsinki Commission decided to establish an agriculture working group. The aim of the group was to draft recommendations on reduction in agricultural pollution. The working group […]
GASTROINTESTINAL DISTURBANCES DUE TO AN ESTABLISHED BACTERIAL CONTAMINATION OF A WATER DISTRIBUTION SYSTEM
In Hörnefors, a village at the east coast of northern Sweden, a new ground water well almost free from detectable bacteria was connected to the old water distribution system, and chlorination was withdrawn. Within four months bacteriological controls indicated the presence of bacterial counts exceeding official limits in drinking water, and an epidemiological survey showed […]
KONTAKTFILTRERING PROCESS – ANVÄNDNING – KONSTRUKTION, Contact Filtration Process – Application – Construction
Contact filtration is a highly effective process for separation of small, even very small, particles and certain solved materials from water. Dispersion is destabilized before introduction in a filterbed containing granular materials. The separation mechanism is mainly the van der Waal effect and adhesion to bed granules. The process is used in purification of drinking […]
BIOLOGISK KVÄVEREDUKTION I REJEKTVATTEN FRÅN SLAMRÖTNING / Nitrogen Removal in Supernatant from Centrifugation of Digested Sludge
Removal of nitrogen from sludge supernatant is one possibility to improve total nitrogen removal efficiency in a sewage treatment plant with about 10 %. The basic treatment gives nitrification and possibility to inoculate the activated sludge process with nitrifiers. This operation improves the plant’s ability to recover nitrification capacity after for instance chock loadings. Denitrification […]
PERFORMANCE OF THE ACTIVATED SLUDGE PROCESS – Statistical modelling
The performance of activated sludge treatment plants is usually influenced by input loads as well as by variations in biological and operational factors related to the treatment process. This implies that the assumption that steady-state conditions exist, is seldom true in practice. Conscientious control programs should be preceded by extensive plant studies concerning the variations […]
A WATER SAMPLER FOR BACTERIOLOGICAL STUDIES
A water sampler comprising a sample device and a separate sample receptacle is presented. The sample receptacle can be sterilized and consists of flexible, exchangeable plastic wall structure located between two rigid circular end bodies. At activation of the sampler the end bodies are pulled away from each other and the sample receptacle is waterfilled. […]
DAGVATTENHANTERING I KANADA- INTRYCK FRÅN EN STUDIERESA / Stormwater Management in Canada – Impressions from a Study Tour
Since stormwater management planning in Canada is included in physical regional planning, the final design of stormwater systems satisfies different economic, environmental, aesthetic and other requirements. Markham symposium 88, described in this paper, is one of several similar meetings during which researchers from different disciplines, hydrologists, city planners, biologists, ecologists and politicians have the opportunity […]