1998-4

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 […]

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 […]

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 […]

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 […]

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 […]

A large number of biological processes have been developed to meet different needs since the early forms of the trickling filter and the activated sludge process were introduced. One of the goals developing new processes often was to increase the total amount ofbiomass in the process. In several of these new processes, the surfaces of […]

The paper presents the Swedish Water Management Research Program towards catchment-based strategies for sustainable resource use (VASTRA). The major goal ofVASTRA research is to develop catchment-based water management strategies which are sustainable from ecological, economical and social perspectives. As a. point of departure, VASTRA views catchments from three pardy overlapping resource perspectives. The first one […]