Realizing The Potential Of Humic Acid In Norway Through Chitosan Treatment Of Drinking Water

Abstract

The current movement towards a circular economy has increasingly focused on turning materials which were previously considered waste products into valuable resources. Humus materials, including humic acid, are potentially valuable resources that can be utilized from surface water treatment for use in agricultural applications to increase yield and remediate soil. Humic acid is commonly observed as color in surface water, and in Norway, is typically removed through coagulation with inorganic salt aluminum sulphate. Although this coagulation method has proven to be very cost-effective, has good performance, is relatively easy to handle and is highly available, it produces substantial amounts of alum sludge. Alum sludge contains a high concentration of alum and many other toxic compounds, like pathogens, organic contaminants and other heavy metals. To decrease the impact on both human health and the environment under current circumstances, there is a necessity to use a natural, more sustainable coagulant in water treatment processes. Chitosan is a natural substance that has been used successfully as a coagulant in water treatment and is a natural material made from the shells of crustaceans. Chitosan is biodegradable and poses no danger to human health and can be used to filter surface water to remove humic acid without contaminating it. This preserves the potential value of humic acid for use in agriculture as a soil amendment. In the result section of this paper, the resource availability of humic acid is mapped with data from all drinking water treatment plants to identify potentially rich sources of humic acid while a mass balance approach is used to determine how much humic acid can be potentially removed via chitosan. The results should be used to identify circular business opportunities which allow for humic acid to be brought back into the natural system and to understand where humic acid is occurring naturally in water sources in Norway and how it can be sustainably harvested.