No abstract

Drinking water utilities in Europe are faced with a growing presence of organic micropollutants in their water sources. The aim of this research was to assess the robustness of a drinking water treatment plant equipped with reverse osmosis and subsequent activated carbon filtration for the removal of these pollutants. The total removal efficiency of 47 organic micropollutants was investigated. Results indicated that removal of most organic micropollutants was high for all membranes tested. Some selected micropollutants were less efficiently removed (e.g. the small and polar NDMA and glyphosate, and the more hydrophobic ethylbenzene and napthalene). Very high removal efficiencies for almost all organic micropollutants by the subsequent activated carbon, fed with the permeate stream of the RO element were observed except for the very small and polar NDMA and 1,4-dioxane. RO and subsequent activated carbon filtration are complementary and their combined application results in the removal of a large part of these emerging organic micropollutants. Based on these experiments it can be concluded that the robustness of a proposed treatment scheme for the drinking water treatment plant Engelse Werk is sufficiently guaranteed.

No abstract

In treatment of groundwater with reverse osmosis, the applied antiscalant can significantly contribute to the formation of biofouling, especially when legislation enforces the use of biodegradable, phosphorous-free products. As an alternative to extensive piloting, the use of the membrane fouling simulator (MFS) is proposed here to assess the biomass growth potential of different antiscalants. The biomass growth potential of two newly developed, phosphorous-free antiscalants was compared to a blank (no antiscalant) and a phosphorous-based antiscalant.The difference in biomass growth potential in the four experiments was significant, with the phosphorous-based antiscalant showing little biomass accumulation and strong and moderate biomass accumulation for the two newly developed phosphorous-free antiscalants. The results of visual observation and pressure measurements of the MFS were compared to the results of autopsy of the membrane sheets. Visual and pressure measurements were found to be a more reliable method to judge the biomass accumulation than membrane autopsy. In a comparison study of MFSs and test rigs with 4" spiral-wound membrane modules, similar results were found, validating MFS use for simulating membrane modules.