Effects of antibiotics and copper in swine wastewater on soil respiration and reed photosynthesis in subsurface flow constructed wetlands
In order to investigate the effects of antibiotics and heavy metals in swine wastewater on soil microorganisms and plant growth in subsurface flow constructed wetlands,horizontal subsurface flow constructed wetlands and vertical subsurface flow constructed wetlands were established,and'root bag'method was used to distinguish rhizosphere and non-rhizosphere soil of reed.According to influent difference,four treatment groups in each kind of wetland were set as follows:the simulated swine wastewater as influent(CK group),swine wastewater added with antibiotics(antibiotics group),swine wastewater added with copper(Cu group),and swine wastewater added with antibiotics and Cu(antibiotics+Cu group).Soil respiration and reed photosynthesis indexes of two kinds of subsurface flow constructed wetlands were monitored for one year.The results showed that the addition of 18.3～39.1 μg·L-1 antibiotics or 1.2 mg·L-1 copper in swine wastewater could inhibit the respiration of rhizosphere and non-rhizosphere soil,and photosynthesis of reed in wetland.Compared with CK group,under the combined stress of antibiotics and Cu,rhizosphere soil respiration decreased by 20.4％～66.3％and 20.8％～77.5％,respectively,while non-rhizosphere soil respiration decreased by 30.4％～71.0％and 23.2％～60.7％,respectively.The reed rhizosphere and non-rhizosphere soil respiration in vertical subsurface flow constructed wetland was significantly higher than that in horizontal subsurface flow constructed wetland in spring,summer and autumn.Under the combined stress of antibiotics and Cu,the reed plant height of horizontal subsurface flow constructed wetland and vertical subsurface constructed wetland decreased significantly compared with CK group at the later stage of operation.Compared with CK group,the net photosynthetic rate of reed in horizontal subsurface flow constructed wetland and vertical subsurface constructed wetland decreased by 11.0％～73.8％and 15.2％～45.3％,respectively,stomatal conductivity and transpiration rate were also inhibited,while the intercellular CO2 concentration of reed increased.Compared with horizontal subsurface flow constructed wetland,vertical subsurface flow constructed wetland has a stronger ability in advanced treatment of swine wastewater.
万方数据
维普
