Removal of endocrine disrupting compounds with membrane processes in wastewater treatment and reuse.

Endocrine disrupting compounds can affect the hormone system in organisms and are the subject of environmental and human health concerns. The effluents of wastewater treatment plants contribute to the emission of estrogenically active substances into the environment. Membrane technology, which is an advanced wastewater treatment option, is the subject of this research. The removal techniques under investigation are membrane bioreactors, reverse osmosis, and nanofiltration. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retention of NP and BPA ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. Regarding the retention of BPA no dependency on the contact angle was observed. Results of the investigation of a full-scale landfill leachate treatment plant indicate a bisphenol A (BPA) removal of more than 98% with membrane bioreactors and reverse osmosis. The mass balance indicates that biological degradation is the most important removal process in the membrane bioreactor configuration.

Efficiency of nanofiltration for the elimination of steroids from water.

Steroid hormones such as the synthetic 17-alpha-ethinylestradiol often persist in the sewage treatment process and metabolites of the natural steroids like estrone from estradiol accumulate resulting in relevant amounts in the aquatic environment. Since biological removal of steroids in the sewage treatment plant is not successfully complete, physical processes such as membrane filtration may become more important. We investigated the elimination of natural and synthetic steroids by nanofiltration using a laboratory membrane reactor. Chemical analysis of 17-beta-estradiol, estrone, estriol, 17-alpha-ethinylestradiol, mestranol, diethylstilbestrol, progesterone and beta-sitosterine was performed after solid phase extraction by GC-MS with standard addition. The elimination rate depended on the nanofiltration membrane material. LFC1 membrane consisting of polyamide removed the steroids over 99% whereas PES10 membrane consisting of hydrolysed polyethersulfone was less efficient, obviously caused by different pore sizes and permeability of the membrane structure.

Occurrence and removal of endocrine disrupters in landfill leachate treatment plants.

Endocrine disrupting compounds can affect the hormone system in organisms. Industrial chemicals with estrogenic effects were detected in large quantities in landfill leachates. Membrane technology has proven to be an effective barrier to these substances and thus widely applied in the treatment of landfill leachate. The removal techniques under investigation are membrane bioreactors, nanofiltration, activated carbon adsorption, ozonation as well as reverse osmosis. Investigations were conducted at two different landfill leachate treatment plants with a variety of process configurations. The xenoestrogenic substances nonylphenol and bisphenol A were detected in high microg/L-ranges in raw landfill leachate. Membrane bioreactors (MBRs) were capable of removing more than 80% of the nonylphenol load. Final effluent concentrations range between 1-12 microg/L nonylphenol and 3-30 microg/L bisphenol A respectively. Reverse osmosis treatment proved to be less effective in nonylphenol and bisphenol A removal than MBR with further polishing stages like nanofiltration and activated carbon adsorption.