Examination of the Use of Support Materials of Natural Origin in Wastewater Treatment

Abstract

Wastewater has become continuously concentrated since 1990 in Hungary as the price of drinking water started to increase intensively from that year. Adding to that, reject water, leakages from landfills, and technological effluents of meat waste processing resulted in high specific nitrogen removal requirements at waste liquids of low COD/TKN ratio. Separated treatment of such waste streams is strongly recommended. We applied zeolite and alginite (supporting materials of natural origin and low price) in three parallel experiments to examine their effects on nitrogen removal using synthetic wastewater in these trials. First we measured the efficiency of a cyclically aerated biofilter (zeolite bed). Then we studied the efficiency of an AS SBR (zeolite powder containing activated sludge unit, operated as sequencing batch reactor), finally we substituted zeolite with alginite. The last one has not been examined for improving nitrogen removal in wastewater treatment in our country till now. We tested the three versions parallel with their proper controls. That is why one of the reactors always contained the seeding activated sludge exclusively to compare the effect of the subsidiary component (zeolite/alginite). The best results were received with using zeolite to the activated sludge. It improved both nitrogen removal and sludge settling. Addition of alginite to the AS also considerably improved sludge settling even at low dosages; therefore further pilot plant controls are recommended before any industrial application of the two support material.