bbk 000000

UDC 628.34:66.081

Maiboroda A. B., Katraeva I. V., Kolpakov M. V.

Effluent polishing with the use of ultrafiltration

Summary

The results of investigating the removal of phosphate ions and suspended solids that enhance eutrophication of water bodies from biologically treated domestic wastewater after secondary settling tank are presented. Experimental studies of effluent polishing with the use of ultrafiltration technology in combination with coagulation were carried in the laboratory of the Nizhny Novgorod State University of Architecture and Civil Engineering. The aluminium hydroxychloride dosage of 20 mg/l as Al2O3 was used as a coagulant. Hollow-fiber module manufactured by Fazerkraft Russian Company with polyvinylidenefluoride was used for tangential ultrafiltration in cycle mode. The membrane module is a device with a cylindrical shell with a bunch of hollow fibers inside with porous walls. The impact of transmembrane pressure on the filtration process was investigated. It was found that the specific flow rate of permeate increases with the increase of transmembrane pressure within the range of 0.05–0.2 bar. The tests showed that 20-fold increasing the concentration of the suspension subject to treatment does not result in any significant decrease of permeate production of the membrane module. Increasing recycling rate (of tangential flow) results in the increase of permeate flow; however, on account of technical and economic aspects, the range of low recycle flow values is of most interest. The results of the studies showed that the suggested ultrafiltration technology provided for almost complete elimination of suspended solids (more than 93% treatment efficiency), 97% reduction of phosphates in wastewater, and reduction to 0.04 mg/l aluminium concentration in permeate.

Key words

suspended substances , membrane module , wastewater aftertreatment , phosphates , ultrafiltration