It is necessary to adjust reaction pH when a single kind of PO4^3- is used as phosphorus source to remove NH4^＋- N in a chemical precipitation process. However, this tedious step could be avoided in experiments that ...It is necessary to adjust reaction pH when a single kind of PO4^3- is used as phosphorus source to remove NH4^＋- N in a chemical precipitation process. However, this tedious step could be avoided in experiments that use the buffering effect of the composite phosphate and employ PO4^3- and HPO4^2- as phosphorus sources, pH was controlled by properly changing the proportion of PO4^3- to HPO4^2-. The influences of pH, material proportion and different addition modes of magnesium on NH4^＋-N removal efficiency were investigated, with NH4^3--N concentration in influent being 200 mg/L. It showed that the ratio of HPO4^2- ： PO4^3- was concerned with phosphorus and NH4^＋-N removal. Under the condition that the total amount of phosphate is definite, the removal efficiency of NH4^＋-N decreased with the enhancement of HPO4^2- concentration, while the efficiency of phosphorus increased. When increasing PO4^3- concentration, it benefited the removal of NH4^＋-N, but the remaining phosphorus was high. The results showed that NH4^＋-N concentration decreased from the initial 200 mg/L to 39.14 mg/L with the remaining PO4^3- at 5.14 mg/L if the ratio of HPO4^2- ： PO4^3- remained at 1：3.展开更多
文摘It is necessary to adjust reaction pH when a single kind of PO4^3- is used as phosphorus source to remove NH4^＋- N in a chemical precipitation process. However, this tedious step could be avoided in experiments that use the buffering effect of the composite phosphate and employ PO4^3- and HPO4^2- as phosphorus sources, pH was controlled by properly changing the proportion of PO4^3- to HPO4^2-. The influences of pH, material proportion and different addition modes of magnesium on NH4^＋-N removal efficiency were investigated, with NH4^3--N concentration in influent being 200 mg/L. It showed that the ratio of HPO4^2- ： PO4^3- was concerned with phosphorus and NH4^＋-N removal. Under the condition that the total amount of phosphate is definite, the removal efficiency of NH4^＋-N decreased with the enhancement of HPO4^2- concentration, while the efficiency of phosphorus increased. When increasing PO4^3- concentration, it benefited the removal of NH4^＋-N, but the remaining phosphorus was high. The results showed that NH4^＋-N concentration decreased from the initial 200 mg/L to 39.14 mg/L with the remaining PO4^3- at 5.14 mg/L if the ratio of HPO4^2- ： PO4^3- remained at 1：3.
