Sorption of humic subtances and metal-humate complexes on aquifer material taken from basins used for artificial recharge of groundwater was studied in batch scale experiments. Distribution of bacteria attached to the material from uppermost layer and from the horizons below the infiltration basin were measured in the field studies. Sorption of aquifer material was heterogeneous in respect to the different position and depth in the infiltration basin. Sorption depended on the numerous factors including composition of the filter sand and properties of humic matter. The heavy metals retarded during artificial groundwater recharge was in the form of metal-humate complexes, dominantly in anionic form or as particulate matter. Sorption of humic substances on the aquifer material was substantially enhanced due to the forming of complexes with heavy metals. Total bacterial number was greatest on the upper most layer of infiltration basin. Slight decreases of bacterial number was observed down to the depth of two meters. There were no significant differences in ratio among major physiological groups of heterotrophic bacteria between layer investigated. The smallest seasonal variation of bacteria was found in the deeper layer below infiltration basin. / Godkänd; 1999; 20070403 (ysko)

Urine separating (US) wastewater systems, where urine is collected and used as a fertiliser, may be a strategy to achieve a high degree of nutrient recycling from human waste to agriculture. The Swedish experiences of US systems show that the design of the toilets and the sewers are of great importance to achieve a working system. One study of the US system in the eco-village in Björsbyn also shows that special attention should be given to avoidance of leakage of water into the urine sewers. During storage of urine the main nitrogen constituent, urea, decomposes to ammonium. Thus, there is a risk nitrogen losses as ammonia evaporation. Several factors concerning the decomposition of urea has been studied in laboratory experiments. A one-time dosage of acid in the beginning of a storage cycle could inhibit the urea decomposition. One strategy to reduce the amount of urine solution produced in a US system may be to use nitrification in combination with drying. Results from a laboratory experiment showed that the method has a potential. However, the system used has to be modified in order to minimise the nitrogen losses. / Godkänd; 1999; 20070403 (ysko)

In-situ determination of thermal properties in bedrock is important for the sizing of larger BTES systems. In-situ values of thermal conductivity may reduce required borehole length up to 30%. This thesis treats a new mobile thermal response test equipment (TED), developed in Luleå, Sweden, 1995-98. TED is set up on a small trailer, and is tried out on groundwater filled boreholes, fitted with single and double U-loop piping. It has been used at several commercial borehole direct cooling systems for telephone switching stations in Sweden, and on test-holes in a well documented closed down heat store in Luleå. The response tests show good accuracy and reliability of the measured thermal conductivity and thermal resistance provided good insulation of the equipment. The tests take into account the interaction of the bedrock with the duct piping and filling, the borehole geometry and groundwater and is a valuable tool for pre-investigations for BTES. / Godkänd; 1998; 20070404 (ysko)

Godkänd; 1997; 20070418 (ysko)

Godkänd; 1995; 20080330 (ysko)

No description available.

No description available.

Godkänd; 1996; 20080328 (ysko)

No description available.

No description available.