Particle and micro-organism removal in conventional and advanced treatment technology
All international drinking water quality standards can be divided into four groups – (micro)biological: bacteria, viruses, cysts, higher organisms, etc. – toxicological: THM, AOX, pesticides, solvents, etc. – organoleptic (esthetic): taste, odor, color, turbidity, etc. – operational: DOC, AOC, pH, Ca2+, HCO3−, Cl−, SO42−, etc. The philosophy on drinking water treatment focuses on the removal of all the undesired species, dissolved and undissolved, available in raw water, in such a way that no new undesired compounds are introduced during treatment such as Al, Cl2, THM, AOX and AOC or during distribution such as Pb, Cu, Cd and asbestos. Special attention is paid to the removal of organic and inorganic colloids and of micro-organisms. Microbiologically stable water during storage and distribution can be realized by removal of nutrients (DOC, AOC) without the use of chlorine of chlorine products. As an example the treatment systems of the Amsterdam Water Supply based on the relatively very polluted raw water of the river Rhine are described. For future expansion of the production capacity membrane processes such as hyperfiltration (HF), electrodialysis reversal (EDR) and ultrafiltration (UF) are investigated. Results are shown on conventional and advanced technology concerning: final water quality, natural and environmental protection, process stability and costs per m3.