Immobilized algae-based treatment of herbicide-contaminated groundwater

摘要

Scenedesmusspecies, immobilized on alginate gel, was found effective in removing nitrate, atrazine, magnesium, phosphorus, zinc, oxadiazon, and triallate from groundwater in a continuous flow reactor. The laboratory-scale experiments with synthetic groundwater, made of 8.8 mg/L NO3-N and 90 mu g/L atrazine, were performed at a hydraulic retention time of 7 days and the temperatures of 20 and 35 degrees C. The highest uptake of nitrate and atrazine was observed at 20 degrees C (97% and 70%, respectively). When tested in actual groundwater, 92% of nitrate, 100% of magnesium, 99.9% of phosphorus, and 92% of zinc were successfully removed at the end of 29 days' treatment operations. The algal beads removed 100% of oxadiazon and triallate in the first 10 days, but some of the herbicides diffused back into the solution toward the end of the treatment process. Practitioner pointsImmobilized algae-alginate beads can remove nitrate, atrazine, oxadiazon, and triallate from groundwater in continuous flow reactor. The uptake rate of nitrate and atrazine is higher in room temperature (20 degrees C). Same algae beads could be reused for herbicide uptake for the average of 10 days. The immobilized system is a natural sustainable alternative that can be used in groundwater pump and treat.