Zugl.: Aachen, Techn. Hochsch., Diss., 1993.

Zugl.: Hohenheim, Universiẗat, Diss.

Universiẗat, Diss., 1999--Essen.

Algal blooms are a common phenomenon in lakes and seas in and around Sweden and poses a problem when found in a drinking water source. Some cyanobacteria can produce toxins which can be with a health problem. To get a safe drinking water it is necessary to be able to remove the toxins from the incoming water. This report has gathered information on cyanobacteria, cyanotoxins and conditions in the water source. Further investigation in two water sources, Bondsjön and Långsjön in Härnösand, have been made as well as a literature review regarding water treatment methods that are effective against cyanotoxins. The results from the lake investigation showed that there was almost no cyanobacteria present in the water in August 2018. Temperature- and water transparency analysis showed that the position of the intake of water to the water treatment plant is placed at a depth that may favour growth of cyanobacteria. A relocation of the intake would probably get a better quality of water regarding risk of cyanobacteria content in to the water treatment plant. The water treatment methods that would be recommended to remove cyanotoxins from the incoming water is pulverised activated carbon (PAC), granular activated carbon (GAC) and membrane filters in the form of nanofilters (NF). PAC is recommended for sporadic use, only when there is cyanotoxins in the water which will require a high control of the incoming water. GAC is recommended as a constant removal technique which will not require the extra control of the incoming water, however it is more sensitive for a high concentration of DOC in the water. NF is also recommended as a constant removal technique and which cross-flow technique is implemented to avoid accumulation of material on the filter surface.

Techn. Universiẗat, Diss.--Hamburg-Harburg, 2000.

Focusing on the selective extraction of the critical raw materials indium and germanium from real bioleaching solutions, extended studies have been carried out using Europe’s first underground hybrid membrane pilot plant (TRL6). In order to transfer former laboratory experiments to pilot scale, NF99 (Alfa Laval) was used for the evaluation of membrane permeance and ion retention. A performance test of microfiltration (MF) and nanofiltration (NF) showed high permeances with low root-mean-square deviation under feed variation (5.2% for MF, 4.7% for NF). Depending on the feed load, a significant permeance drop of up to 57% for MF (3 bar) and 26% for NF (10 bar, 1.1 m s−1) was observed. The NF retention performance showed that, without regular chemical cleaning, the selectivity between the target elements degraded. By introducing acidic-basic cleaning steps, it was possible to keep the retention behavior at an approximately constant level (In 91.0 ± 1.3%; Ge 18.2 ± 5.5%). In relation to the specified target, the best results could be achieved at low pressure (7.5 bar) and a maximum overflow velocity of 1.1 m s−1, with a retention of 88.4% for indium and 8.8% for germanium. Moreover, the investigations proved the functionality and long-term stability of the underground membrane device.