Water Intelligence Online © IWA Publishing 2005

UV/H2O2 Retrofit of PWN's Water Treatment Plant Andijk for Primary Disinfection and Organic Contaminant Control

Joop Kruithof*, Peer Kamp*, Mike Belosevic**, Mihaela Stefan***

* NV PWN Water Supply Company North Holland, PO Box 2113, 1990 AC Velserbroek, The Netherlands
** University of Alberta, Department of Biological Sciences, Edmonton, Alberta, Canada T6G 2E9
*** Trojan Technologies Inc., 3020 Gore Road, London, Ontario, Canada

N.V. PWN Water Supply Company North Holland has replaced breakpoint chlorination at their Andijk drinking water treatment plant. Major objectives are restriction of disinfection by-product formation, increased pathogen inactivation and multiple barriers for organic contaminant control. The aim of this study was to show the feasibility of UV/H2O2 treatment for primary disinfection and organic contaminant control in direct surface water treatment.

A 2-3 log inactivation of Giardia muris and Cryptosporidium parvum was achieved by an UV dose of 20 mJ/cm2. The highest UV dose was needed for the inactivation of spores of sulphite reducing clostridia. For the required inactivation of all micro-organisms an UV dose up to 105 mJ/cm2 was needed.

Reactivation of protozoa was established for an UV dose up to 25 mJ/cm2. For doses higher than 60 mJ/cm2 no reactivation was observed.

An 80 % degradation of pesticides, endocrine disruptors and pharmaceuticals can be achieved by a proper combination of electric energy and hydrogen peroxide. At this conversion primary metabolite formation was insignificant, while no bromate was formed.

The electric energy for organic contaminant control is much higher than required for disinfection e.g. 540 mJ/cm2 and 6 mg/L H2O2.

Residual H2O2 removal, AOC and nitrite control are achieved by post GAC filtration.
In view of the very promising results PWN has installed UV/H2O2 at their Andijk plant. Three streets of 4 Trojan Swift 16L30 reactors are in operation since late 2004.

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UNIQUE ID: 200504006