Monitoring endocrine activity in kraft mill effluent treated by aerobic moving bed bioreactor system

Abstract

A Moving Bed Bioreactor (MBBR) was operated at three different hydraulic retention times for a period of 414 days. The fate of the extractive compounds and the estrogenic activity of the Pinus radiata kraft mill effluents were evaluated using Yeast Estrogen Screen (YES) and gas chromatography - mass spectrometry (GC-MS) detection. Results show that the MBBR reactor is able to remove between 80-83% of estrogenic activity present in the kraft mill Pinus radiata influent, where the values of the effluent's estrogenic activity ranged between 0.123-0.411 ng L(-1), expressed as estrogenic equivalent (EEqs) of 17-a-ethynylestradiol (EE2 eq.). Additionally, the biomass of the MBBR reactor accumulated estrogenic activity ranging between 0.29-0.37 ng EEqs EE2 during the different Hydraulic Retention Time (HRT) operations. The main groups present in pulp mills effluents, corresponding to fatty acids, hydrocarbons, phenols, sterols and triterpenes, were detected by solid phase extraction (SPE) and gas chromatography - mass spectrometry (GC-MS). The results suggest that the sterols produce the estrogenic activity in the evaluated effluent.