植物床-沟壕系统的藻类捕获功能

Algae trapping function of plant-bed/ditch systems

采用原位实验验证植物床-沟壕系统的藻类捕获功能。结果表明:该系统能够有效拦截和捕获源水藻类。在水力梯度驱动下,约35%源水进入高位小沟流经植物床内部根孔结构而汇至低位小沟。低位小沟内叶绿素a(Chl-a)浓度显著低于高位小沟(P=0.0239),其降低比例为11.1%。以植物床-沟壕系统为结构形式的根孔净化区其出水Chl-a浓度较源水整体下降了27.0%。估算该片根孔净化区捕获藻类鲜生物量约122 kg/d。石臼漾湿地共含根孔净化区11片,按供水25万t/d计,估算捕获藻类鲜生物量约1 100 kg/d。

This case study corroborated the algae trapping function of plant-bed/ditch system through in si- tu field testing. Results showed that the system could effectively intercept and trap algae from source water. Un- der the driving of hydraulic gradients, about 35% source water flowed into the higher small ditch, and exuded through the root channel structure inside plant bed into the lower small ditch. The ehlorophyll-a （Chl-a） con- centration in the lower small ditch was significantly lower （P = 0. 0239） than that in the opposite higher small ditch. The decline percentage of Chl-a concentration amounted to 11.1% between both sides of plant bed. The Chl-a concentration dropped down by 27.0 % at the outlet of examined root channel purification zone with plant- bed/ditch system as structure form. According to rough estimation, this patch of root channel purification zone could trap algae fresh biomass of about 122 kg/d. Shijiuyang constructed wetland contains altogether 11 patches of root channel purification zones and provides 250 000 t/d purified raw water for the drinking water plant. The total trapped algae fresh biomass reached up to about 1 100 kg/d.