NITRIFIKATION I BIOBÄDD OCH DENITRIFIKATION I EN HÖGBELASTAD AKTIVSLAMANLÄGGNING – DRIFTERFARENHETER FRÅN RYAVERKET / Post nitrification in a trickling filter and predenitrifaction in a non-nitrifying activated sludge system – operational experience from the Rya WWTP
The Rya Wastewater Treatment Plant, serving the Göteborg Region on the West Coast ofSweden has been ex- ended for nitrogen removal. The process includes post nitrification in trickling filters and predenitrification in non-nitrifying activated sludge system. In this paper some experience from the first year of full-scaleoperation will be related. The staied effluent standard of […]
DECLINING WATER CONSUMPTION IN COMMUNITIES: SIGN OF EFFICIENCY AND A FUTURE CHALLENGE
The paper describes the trends of water consumption, particularly per capita in Finland from 1970 to 1996 and includes comparisons from other countries. The per capita consumption started to decline due to two major impetus; the energy crisis of 1973 and the Wasrewater Surcharge Act of 1974. The latter more than doubled the average price […]
COMPARISONS OF HYDROGRAPHS FROM A KINEMATIC WAVE MODEL AND TWO DYNAMIC MODELS / Sammenligning av hydrogrammer fra en kinematisk bolgemodell og to dynamiske modeller
This paper describes differences between the urban drainage models MOUSE, EPA-SWMM and NIVANETT, relating to the routing of flows through pipes. NIVANETTs kinematic wave procedure simulates rather similar hydrographs to those of MOUSE, when the conduit lengths are shorter than ca. 500 m and the slope is steeper than ca. 1/1000. Keeping in mind that […]
CHEMICAL OXYGEN DEMAND (DICHROMATE VALUE) AND THE SWEDISH BAN ON MERCURY, OPPORTUNITIES AND PITFALLS
The Chemical Oxygen Demand (COD) test is a key parameter for process control and the routine monitoring of effluent quality in wastewater. However, the present procedure for determination has ro be replaced becausethe scale of COD test chemicals containing Hg will probably not be permitted after the year 2000 in Sweden. Mercury-free procedures are reviewed […]
DISTRIBUTION OF MICROORGANISMS IN THE COURSE OF ARTIFICIAL RECHARGE OF GROUNDWATER AT BALTEZERS WATERWORKS, RIGA / Fördelning av mikrorganismer vid Baltezers anläggning för konstgjord infiltration i Riga
Artifcial recharge of groundwater is being used for drinking warer production in Latvia. The ultimate removal of organic matter from the surface water during artificial recharge of groundwater is accomplished by microrganisms living in the subsurface. In order to predict changes of water quality, more information about the disribution of microorganisms between infiltration ponds and […]
HOBAS GAP-RÖR – FRÅN IDE TILL VÄRLDSPRODUKT / Hobas GRP-pipes – From idea to world product
The paper describes the historical development of Hobas GRP-pipes from one person’s idea about a new design of GRP pipes to a complete new pipe material used world wide. The properties of the new material is briefly described as well as the design and Mr Carlström’s work with the standardisation of GRP pipes
COST EFFICIENT SLUDGE LIQUOR TREATMENT / Kostnadseffektiv behandling av rejektvatten
For sludge liqours the normal way is to lead the different reject water streams back to the inlet of the treatment plant thus producing high and irregular internal loads that can be difficult to control and which cause problems for the normal treatment. A solution to the problem is to introduce a separate treatment. Sludge […]
LUKT OG SMAK AV DRIKKEVANN – KAN VI IDENTIFISERE PROBLEMKOMPONENTENE? / Drinking water off-flavours – can we identify their chemical constituents?
Odour and taste problems are among the most common reasons for consumer complaints to drinking water quality. This work describes extraction and quantification of volatile organic components (VOC) in water, including well-known odour components and disinfection byproducts. The analytical approach is based on purge and trap of VOC from drinking water at various experimental conditions […]
PHOSPHORUS MANAGEMENT AND SOCIETAL STRUCTURE Hampered effluent accumulation processes (HEAP) in different areas of the Swedish society / Fosforhantering och samhällsstruktur Ackumulationseffekter i det svenska samhället
Some of the problems of phosphorus pollution and source exhaustion are identified to be time-dependent, structural problems. This is demonstrated to be the case in land independent animal production, in urban settlements and in the waste-water treatment – landfill cycle. A calculation indicates that saturation of the systems can take place in the time range […]
LÅNGSAMFILTRERING – EN ENKÄTUNDERSÖKNING AV SVENSKA FILTER Slow Sand Filtration – an Investigation of Swedish Slow Sand Filters
At present there is an increasing interest in rhe reduction of natural organic matter, NOM, from drinking water by biological processes instead of chemical processes. In Europe as well as in the US a lot of research is done to increase the knowledge of biological processes in slow sand filters. Removal of organic matter in […]