Investigation on the removal of selected organic micropollutants from municipal wastewater by trickling filters and sand filters

Abstract

Recently several different types of organic micropollutants are detected in the aquatic environment as a result of inadequate wastewater treatment. The adverse effects of the various micropollutants such as pharmaceuticals, personal care products, pesticides, herbicides and industrial chemicals with concentrations less than 1 μgL-1 on the ecosystem are challenging to be assessed. Thus, sufficient approaches are indispensable to curtail the negative impacts that these substances may have on the environment and human health. Much research was done especially in the recent years on the fate and removal of these emerging contaminants from wastewater by different measures. In this work, a systematic literature review (SLR) is conducted to determine the current state of research in micropollutant removal around the globe which discovers the existing approaches for micropollutant treatment and enables applying an unbiased evaluation. Then one of the identified approaches (sand filter and trickling filter) which is the objective of this study was investigated, and the removal behavior of micropollutants by this method was experimented. The influent and effluent of the trickling filters and sand filters in LFKW wastewater treatment plant were taken and the effect of biodegradation and sorption on the removal of the compounds was investigated. Micropollutant analysis regarding non-polar substances was performed bygas chromatography-mass spectrometry (GCMS) while high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MSMS) was applied instead for polar compounds. Furthermore, the molecular orbital energies of the substances were investigated. UV/Vis spectrophotometry and DOC analysis were other experimental approaches that have been used in order to shed some light on the behavior of these contaminants. As a result of this study, micropollutants are classified in different groups based on their physical-chemical properties, providing it as an essential factor affecting micropollutant removal behavior. Moreover, different correlations between the physical-chemical properties and the micropollutants elimination are assessed.