Fate of estrogens in biological treatment of concentrated black water

Feminisation of male fish is for a large part due to compounds entering surface waters via wastewater. For domestic wastewater, two natural estrogens, estrone and 17-estradiol and the synthetic estrogen, constituent of the contraceptive pill, are mainly responsible for this effect. These compounds are excreted by humans and in conventional treatment systems sometimes insufficiently removed. A solution can be found in the implementation of innovative sanitation concepts like source separated collection and treatment of black water (toilet), grey water (shower, kitchen, laundry) and rain. As the three compounds will be mainly present in black water, contamination by storm water overflows is completely excluded and the concentrated character of the wastewater allows for more energy efficient treatment systems. Present research showed the first step, anaerobic treatment where energy is as well produced as conserved, is unfavourable to satisfactory remove these compounds and the aerobic post-treatment only partly. As the volume of the stream is remarkably smaller compared to conventional systems (7 liter black water per person per day against 200 liter wastewater per person per day), a necessary tertiary treatment, for which ozonation is promising, will be more compact. Besides, current research shed light on several parameters influencing the degradation of estrogens in biological systems