Abstract: Reeds (Phragmites) and gravel were used to develop pilot scale solar aerated vertical subsurface flow constructed wetlands to treat domestic wastewater. The hydraulic loading rate was set 400 mm/d and air to water ratio was 10∶1. Experimental results indicated that solar aeration resulted in 24.8%, 9.4%, 15.7% and 11.5% increment in total mean removal respectively for ammonia-nitrogen(NH₄-N), total nitrogen (TN), soluble reactive phosphorus (SRP) and total phosphorus(TP) with corresponding influent concentrations of 5.14 mg/L, 7.56 mg/L, 0.40 mg/L and 0.53 mg/L. Low atmospheric temperature and influent concentration, however, caused a negligible role of solar aeration in nitrogen and phosphorus removal. For the present experiment apparatus, the expenditure of solar aerated wetland is 2.85 times the non-aerated wetlands. Considering a total investment over a period of 20 years, the cost to treat domestic wastewater for solar aerated wetland is only 0.02 RMB/m³ higher than that of non-aerated wetland. In conclusion, solar aerated constructed wetland is a promising solution of treating domestic wastewater with competitive technical and economical advantages.

Key words: solar aeration, constructed wetland, nitrogen, phosphorus, cost of treatment