Perkolationsfilter
En undersökning av reningseffekt med avseende på järn och mangan
This master thesis has been done in cooperation with Sweco Viak AB in Sundsvall. The aimwith the project is to investigate the purifying effect of percolation filter due to iron andmanganese. The overall goal was to investigate how the parameters surface load,sandfractions, and burden time affect the purifying effect. The expectation is to optimize thedesign and find a demouldning of the filter that gives sufficient purifying with a highersurface load. As an attempt to accelerate the curing of the filter, experiments with a layer ofsand which surface has been covered with manganese ore (MnO2) on top of the filter havebeen done.As test filters 10 L bars were used and the experimental work was performed at thewaterworks in Hassela and Munkbysjön.In Hassela different sandfractions were tested. The manganese was very easy to oxidize andno difference in the reduction of manganese content in the water between the different filterswas observed. The iron was on the other hand very difficult to oxidize and no reduction of theiron content was obtained even though the water was aerated before entring the filters. Thismight occur when the iron is bounded in humuscomplexes. When it comes to the differentsandfractions, the fine sight can not be recommended as a method to treat water in Hassela asit didn?t work with a surface load of 0,2 m/h. With those results in mind percolationfilter isnot a method that can be recommended in Hassela.At the waterwork in Munkbysjön experiments were done with sand which surface had beencovered with MnO2. The difference in curing time was barely measurable which in this casemakes it unnecessary to use the preparated sand. When the surface load was increased thereduction of manganese content was uneffected. Even the reduction of the iron content wassufficient although no aeration was used. A percolation filter could work very well inMunkbysjön, but experiments with even higher surface load and sand with a highercoarseness are to be recommended before a filter is established.