The removal of phosphorus from reject water in a municipal wastewater treatment plant using iron ore

Abstract

BACKGROUND: Reject water (return liquor) from dewatering of anaerobically digested activated sludge in municipal wastewater treatment plants contains from 10 to 50% of the phosphorus load when being recycled to the aeration tank. Phosphorus removal from reject water could be an effective way to decrease phosphorus loads entering the aeration tank. An innovative approach involves the replacement of iron salts, which are commonly used for phosphorus removal, with ferrous ions produced by iron-reducing bacteria from iron ore. The aim of the research was to examine the feasibility of phosphorus removal from return liquor using bioreduction of iron ore.

The removal of phosphate from wastewater using anoxic reduction of iron ore in the rotating reactor

“…Significant phosphorus removal due to adsorption of phosphorus on surface of iron ore particles in the static reactors was shown in the previous study [12]. However, removal of phosphate by adsorption in the rotating reactors was not associated with size of initially loaded iron ore particles and was 65% of total phosphorus removal in all rotating reactors.…”

“…However, it was shown previously that the ferrous production rate in the static reactors statistically reliably and positively correlated with the specific surface area (surface-to-volume ratio) of iron ore particles and negatively with their size, so that the highest rate of ferrous production was in the static reactor with the smallest particles, 0.6 mm [12]. This contradiction between rotating and static reactors can be explained by the formation of fine iron ore powder in the rotating reactor.…”

“…The feasibility of phosphorus removal from reject water using anoxic bioreduction of iron ore has been demonstrated [12]. However, that study was performed in the static reactors, where diffusion was the major mechanism of mass transfer for Fe 2+ and HPO 4 2− ions and the rate of ferrous production was associated with size of the iron ore particles and their specific surface.…”

“…It was shown that the BioIronTech process can be used for improvement of sludge quality [7], treatment of fat-containing wastewater [11], removal of xenobiotics such as diphenylamine, m-cresol, 2,4-dichlorphenol and p-phenylphenol [1]. The cost of Fe of iron ore is approximately US$ 140 per ton of Fe in iron ore, which is 7.2 times cheaper than Fe of iron salt [12].…”

Construction Biotechnology: a new area of biotechnological research and applications

“…Bioreduction of iron ore using products of acidogenic fermentation or other cheap electron donors (Ivanov et al 2009;Guo et al 2010):…”