A Full-Scale Study On Phosphorus Removal From Biological A/O Process Enhanced by Zeolite

In a full-scale test, zeolite enhanced the biological nitrification, but the nitrate of returning mixed-flow in the anaerobic process inhibited the release of the polyphosphate accumulation microorganisms and had little effect on the phosphorus removal in the biological A/O process. It was suggested that we use the method of chemical phosphorus removal in the process. Aluminium and ferric salts had a good effect on chemical phosphorus removal, and had no correlation with locations. When adding Al ₂ (SO ₄ ) ₃ ldr18H ₂ O, the molar ratio of the TP and Al at 1:1.5, the rate of phosphorus removal was more than 85%. When adding FeSO ₄ ldr12H ₂ O, the molar ratio of the TP and Fe at 1:1, the rate of phosphorus removal was more than 80%. When adding 20 mg/L FeSO ₄ ldr12H ₂ O and 30 mg/L Al ₂ (SO ₄ ) ₃ ldr18H ₂ O in the anaerobic process, the mixed phosphorus removal agent could remove nearly 90% of phosphorus in a biological A/O process enhanced by zeolite. At the same time, the content of phosphorus could reach the effluent discharge standard.