Treatment of industrial landfill leachates by chemical and biological methods: Ozonation, ozonation plus hydrogen-peroxide, hydrogen peroxide and biological post-treatment for ozonated water

The objective of this study was to determine a suitable treatment method for variable waters from a forest industry landfill site. The main target was to find out the impact of different chemical treatments on the composition and biodegradability of those waters. Earlier studies have shown that biological treatment alone is not a suitable treatment method for these waters. That is why ozonation, ozoriation + hydrogen peroxide and hydrogen peroxide treatment were studied in a laboratory scale. The ozonated waters were also biologically post-treated. All the methods studied were able to degrade a part of the organic compounds, and convert them into a more biodegradable form. Also the BOD/COD-ratio increased significantly. The removal of organic compounds by ozonation was 30 - 50%. Hydrogen peroxide addition did not improve the degradation. The combination of pre-ozonation and biological post-treatment gave a total TOC removal between 50 - 95%.