A laboratory experiment was performed to investigate phosphorus and nitrogen removal from synthetic wastewater by intermittently aerated activated sludge process packed with aluminum and silver plate. Three continuous experimental processes, i. e. an intermittently aerated activated sludge process(Run A), an intermittently aerated activated sludge process with an aluminum and silver plate packed into the reactor(Run B), and a reactor post stage(Run C) were compared. In the batch experiments, the phosphorus removal time in the reactor packed with aluminum and silver plate simultaneously was faster than that of the reactor packed with only an aluminum plate. More phosphorus was removed with an increase of NaCl concentration. The pitting corrosion of aluminum does not affect the performance of the biological treatment. The total nitrogen removal efficiency in Run B was 57% and 43.6% at the HRT of 12 and 6 hours respectively. The effluent PO4-P concentration as low as 1.0 mg/L could be obtainable through the continuous experiment in Run B at HRT of 6 hours.

The purpose of this study was to evaluate the effects of Ca(OH)2 and CO2 additions on the corrosion of metal coupons (ductile iron, galvanized steel, copper and stainless steel). Corrosion rate and released metal ion concentration of ductile iron and galvanized steel was decreased by adjusting alkalinity, calcium hardness and pH with Ca(OH)2 & CO2 additions named CCPP (Calcium Carbonate Precipitation Potential) index control process. But the effects of Ca(OH)2 & CO2 additions on copper and stainless steel were less than those on ductile iron and galvanized steel. When ductile iron coupon was exposed to water treated with Ca(OH)2 & CO2 additions, the main components of corrosion product formed on its surface were CaCO3 and Fe2O3 or Fe3O4, which often reduce the corrosion rate by prohibiting oxygen transport to the metal surface.

The fundamental experiments on the phosphorus removal from water were carried out by the batch and continuous reactors which used aluminium and copper plate. In this systems, the phosphorus was removed by aluminium ion generated with the electrochemical interaction (pitting corrosion) of aluminium and copper. In the batch experiments, the efficiencies of phosphorus removal increased when the surfaces of aluminium and copper plate were brushed. The phosphorus removal by aluminium ion was affected the copper plate and NaCl in this system. The optimal pH values were 5 and 6 for the phosphorus removal. The efficiency of phosphorus removal increased with increasing NaCl concentration, surface area of aluminium and copper plate. The CuSO4·5H2O instead of copper plate could be used as Cu source. The effluent PO4-P concentration as low as 2㎎/ℓ could have been obtained during the continuous experiment at HRT of 48 hrs.