D10: Impact of Contaminants - Hydromod

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Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas EUROLAKES D10: Impact of Contaminants FP5_Contract No.: EVK1-CT1999-00004 Version: 4.0 Date: 25/07/01 File: D10-vers.4.0.doc Page 112 of 136 Processes which might have an effect on the degradation of endocrine substances State of research Currently there are no publications available on the effect of drinking water processes on endocrine substances. A research programme in this has started on June 2000 in Austria under the Title “Austrian Research Co-operation on Endocrine Modulators (ARCEM). The program is scheduled up to mid 2003 and is initiated by Austrian Scientists from different universities together with the Austrian Federal Environment Agency and the Federal Ministry for Agriculture, Forestry, Environment and Water Management. One module under this programme will deal with the aspects of drinking water treatment. Under this programme the following treatment processes will be considered with regards to its effect on endocrine substances. 1. Adsorption 2. Metabolism of the substances under influence of oxidants like ozone, ozone in combination with UV radiation, persulfate, caroate. 3. Metabolism of the substances under influence of chlorine compounds like chlordioxid, hypochlorit and hypochlorit in combination with UV radiation 4. General effect of UV radiation on the substances 5. Biological reduction of these substances by biological active activated carbon 6. Biological reduction of these substances by slow sand filtration 7. Biological reduction of these substances by biological Iron and manganese filters 8. Influence of precipitation, flocculation and sedimentation on these substances. However results are not expected before mid 2001 Based on the current knowledge of the effects of wastewater treatment processes on endocrine substances the following processes could in the opinion of the author be suitable to reduce or eliminate endocrine substances. However it is only the hypothetical opinion of the author. Membrane processes Endocrine substances can theoretically be fully removed from water (drinking water and also waste water) by membrane processes. Membrane bioreactors are a particularly promising alternative to conventional activated sludge treatment with respect to effluent quality, not just regarding the removal of endocrine disrupting substances [SCHWIER et al. 2001]. These processes are classified according to the size of the pores of the membrane and thus by the size of water contents retained.(Figure 11-7).
Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas EUROLAKES D10: Impact of Contaminants FP5_Contract No.: EVK1-CT1999-00004 Version: 4.0 Date: 25/07/01 File: D10-vers.4.0.doc Page 113 of 136 Figure 11-7 classification of membrane processes according to [DEGREMONT Water Treatment Handbook, 1991] Reverse osmosis: The raw water is pumped at 5 to 100 bar against a semi-permeable membrane which allows water to pass through while solutes are retained except for certain organic molecules similar to water (with a low molecular weight and strong polarity). In order to prevent fouling and scaling on the membrane, pre-treatment of the water with processes like ion exchanging, flocculation, micro filtration, treatment with polyphosphates, etc. is necessary. The treated water needs further treatment for pH adjusting and increasing of salt concentration. 20 % of the treated raw water remains as wastewater which disposal is very costly. With that process nearly pure water can be produce, but technical needs and costs are tremendous. Ultra filtration: These membranes allow to retain compounds of a defined size in the raw water. Ultrafiltration allows only the coarsest solutes (macromolecules) to be rejected. The process is mainly applied to retain bacteria and viruses. Also turbidity can be reduced down to 0,1 FNU. Ultrafiltration is frequently used for recycling of backwashwater from filtration. Micro filtration These membranes do not change the composition of the solution in any way, only suspended solids, colloids, bacteria etc. are rejected. It is assumed that micro filtration is suitable to retain endocrine substances only to a very little extent. Electrodialysis: If a liquid that is rich in ions, is subjected to an electrical field by means of two electrodes with a continuous potential difference applied between them, the cat-ions will be attracted to the negative electrode and the an-ions will be attracted to the positive electrode. If nothing impedes their movement, they will each lose their charge on the opposite sign electrodes and thus electrolysis takes place. However if a series of selective dialysis membranes is placed between the electrodes cation membranes, permeable only to the cations, and anion membranes, permeable only to the anions the migration
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D10: Impact of Contaminants - Hydromod

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