Effects of Coking Wastewater on the Growth of Five Wetland Plant Species.

In order to investigate the effect of wetland plants in the treatment of coking wastewater, Oenanthe javanica (Blume) DC (OC), Artemisia selengensis Turcz. ex Bess. (AB), Echinochloa crusgalli (L.) Beauv. (EB), Brasenia schreberi J.F.Gmel. (BG), and Lythrum salicaria L. (LL) were used to remove ammonia-nitrogen and chemical oxygen demand (COD) from coking wastewater. Results showed high concentrations (> 30%, diluted by deionized water) of coking wastewater caused decreased photosynthetic rate, transpiration rate, and relative growth rate in all studied plants. OC, BG, and LL showed higher adaptability than AB and EB. Wastewater concentrations < 30% resulted in less affected growth of OC, BG, and LL; However, AB and EB were suppressed when coking wastewater concentrations were > 15%. High concentrations of coking wastewater generated oxidative stress which resulted in increased malondialdehyde and proline contents and inhibition of superoxide dismutase. OC, BG, and LL were considered tolerable species in purifying coking wastewater (concentrations < 30%).