Studies on Simulated Sewage Purification by Means of Twelve Emerging Hydrophytes

Pot-culture experiments were conducted to study the effects of twelve Beijing local perennial emerging hydrophytes on purifying simulated sewage under different hydraulic retention times.Results showed that the purification effect on total nitrogen and total phosphorus in sewage increased with hydraulic retention time.When hydraulic retention time was 30 days,all hydrophytes on TN removal rate were more than 95% and TP removal rate were more than 85% except Acorus calamus'Variegatus' and Typha minima Funk.Compared with control,all hydrophytes had different significances.During the experiment period,Lythrum salicaria L.,Iris pseudacorus L.and Zizania latifolia(Griseb.) Turcz.ex Stapf.s absorption of nitrogen and phosphorus had great contribution to their increases of biomasses.Considering the purge rate and content variation,Lythrum salicaria L.,Sagittaria trifolia L.,Iris pseudacorus L.s purifying effects on TP were particularly prominent;Acorus calamus L.,Sagittaria trifolia L.,Pragmites australis(Cav.)Trin.exsteud.'s purifying effects on TN were in top three among twelve hydrophytes.Compared with other plants,Acorus calamus L.and Lythrum salicaria L.had advantages on nitrogen and total phosphorus in sewage.