Removal of geosmin and 2-methylisoborneol using algaecides and chemicals in potable water.

摘要

Common taste and odor compounds in drinking water include 2-methylisoborneol (2-MIB) and trans-1,10-dimethyl-trans-9-decalol (geosmin). These compounds are difficult to remove through conventional water treatment. Thus, additional research is necessary to find cost-effective methods for removal of geosmin and MIB. The effects of algaecides and chemicals in various conditions (dosage, pH, temperature, turbulence, biodegradation) on geosmin and MIB were investigated, and compounds were analyzed through gas chromatograph and mass spectrometric methods (GC/MS) with solid-phase microextraction (SPME). The experiments were performed using both deionized water and lake water samples. At the recommended manufacturer's dosages of six chemicals (Earth TecRTM, Cutrine Plus, Algimycin PWF, Sulfuric Acid, Phycomycin SCP, Calcium chloride dehydrate), removals of geosmin and MIB were unsatisfactory. Acidic conditions were shown to remove the compounds through dehydration. In pH experiments, MIB started to be removed as pH was reduced and was completely removed at pH 3.0. Geosmin showed removal at pH 3.5 and complete removal at pH 2.0. When the samples were returned to neutral (pH=7.5) using sodium hydroxide, geosmin was recovered around 50%, while MIB remained dehydrated. For biodegradation experiments, geosmin was volatilized around 10 -30% and MIB was volatilized around 5-10% for 8 days, but there was negligible impact of biodegradation. In temperature and turbulence experiments, geosmin and MIB removals showed negligible impacts of temperature and turbulence. In futher experiments, three chemicals were found to remove geosmin and MIB as follows: sodium sulfate 70-80%, calcium chloride dehydrate 40-50%, copper sulfate 40%-70%, all at high dosages.