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well almost free from detectable bacteria was connected to the old water distribution system, and chlorination was withdrawn.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 […]
CALCULATION OF CRITICAL LOADS FOR ACID DEPOSITION
The critical load, defined as the maximum load of acid deposition that will not cause certain adverse effects, is calculated by using a mass balance for alkalinity for the catchment, forest soil or lake system considered. This simple method estimates the critical load from site characteristics such as mineral composition, bioremoval of base cations and […]
INTERKALIBRERING AF MIKROBIOLOGISKE VANDANALYSER I DANMARK, Intercalibration of Microbiological Analyses in Denmark
In Denmark, as in other countries, the need for supervision and control with the water pollution is increasing. Microbiological and chemical water analyses are an important tool for this control. However, the condition for using the results of these analyses is a good and reliable quality of the analyses. In Denmark an important part of […]
ORGANISKT MATERIAL I VATTEN. – EN JÄMFÖRELSE AV RESULTAT FRÅN OLIKA ANALYSMETODER, Organic Substances in Natural Water. A Comparison of Results from Different Analytical Methods
For the determination of total organic substances in water three, principally different methods are available. These are chemical oxygen demand (COD), total organic carbon (TOC) and biochemical oxygen demand (BOD). Theoretical and empirical relationships between results obtained with these methods are discussed based on literature and own results. Variations in the relationships are mainly due […]
DETERMINATION OF THE INORGANIC CHLORIDE CONTRIBUTION TO THE EXTRACTABLE, ORGANICALLY BOUND CHLORINE IN FISH
The contribution of inorganic chloride to the extractable, organically bound chlorine (EOCl) in fish was investigated by adding radioactively labelled chloride to an aquarium with perch (Perca fluviatilis). The total radioactivity in fish tissue was compared to the radioactivity in the corresponding EOCl extracts. The concentration of inorganic chloride was reduced about 120,000 times during […]