comparison in reduction of solids, turbidity and ec between nanofiltration membrane bioreactor and activated sludge

hospital wastewater has special importance since having pathogens, radioactive materials, pharmaceutical wastes and heavy metals. removing them into environment without any treatment may cause serious problems for the public health. membrane biological reactor is the combination of the activated sludge and membrane filters. this research has investigated the performance of the nano-filtration in a membrane biological reactor (nf-mbr) in the pilot scale in comparison to the activated sludge system which is very common in hospitals and has been utilized in the babol hospital`s wastewater treatment plant. nf-mbr pilot make the chance for the biological process to act in long srt (in this case 62 days). therefore the mlss concentration in the aeration tank reach to over 6000 mg/l. tds and ec removal is obtained 60% and turbidity and tss removal is obtained up to 99%. the advantageous of this system were having no sludge removal in the experimental period, no chemical backwash of the nano-membranes and excellent and nearly constant quality of the effluent.