Use of zirconium and chitosan coagulants for physicochemical and hygienic water treatment

Abstract

Use of aluminium and ferric salts for drinking water production is almost global. Beneficial aspects of their use are extensively recognized. However, factors, such as deteriorating water quality, health concerns and rising levels of environmental pollution, pose a series of requirements for compounds intended for water treatment in the future. Alternative coagulants often possess properties that are lacking for their traditional competitors or offer a more sustainable solution. Nevertheless, their practical introduction is often difficult, as it is associated with some risks, and, therefore, scepticism. To address doubts, explicit characterization of the new chemicals, acknowledgement of practical and economical experience from the water plants using them, can be essential. Two of these alternative compounds – zirconium (Zr) and chitosan – were investigated in the research described in this thesis. The present work attempted to highlight use of Zr and chitosan coagulants for drinking water treatment in Norway and acknowledge various aspects associated with their use and stimulate further interest in these two compounds.

Jernsalter og aluminium brukes over hele verden og er anerkjent for sine egenskaper. Økende humusnivå i vannkilder og økende miljøforurensning, skjerper imidlertid kravene til stoffer som er beregnet for vannbehandling. Alternative koagulanter har ofte egenskaper som vi ikke finner hos tradisjonelle koagulanter og tilbyr en mer bærekraftig løsning. Dette arbeidet evaluerer mange faktorer relatert til bruk av Zr- og kitosankoagulanter for produksjon av drikkevann, noe som gir et verdifullt innblikk i deres egenskaper.