Study of oil products and heavy metals removal from surface runoff in phytofilters

Summary

Internationally the use of bioengineered facilities including phytofilters in the treatment of surface runoff from urban lands is gaining ground. The use of phytofilters in moderate climate belts has some restrictions related to the decline in treatment efficiency during the periods of near-zero temperatures because of the retardation of biochemical processes in plants and soil microorganisms. A technical solution of the described problem is proposed that consists in adding materials with sorption and ion-exchange properties (peat and zeolite) into the filter media. The efficiency of removing oil products and heavy metals (lead, copper, aluminium, iron) from the simulated solution of surface runoff in a pilot laboratory phytofiltration plant with the use of higher plants: common reed grass (Phragmites commnis), mace reed (Tpha latiflia) and Iris pseudacorus was studied. The efficiency of removing oil products was 95.5–98.9%, and that of heavy metals – 66–99.3%. It was stated that during the vegetation period partial phytoregeneration of the filtration media from the trapped oil products and heavy metals occurs under the effect of higher plants and rhizospheric microflora. By experiment it was determined that the efficiency of phytoregeneration from oil products decreases in series: common reed grass – Iris pseudacorus – mace reed; from heavy metals: Iris pseudacorus – common reed grass.

Key words

oil products , surface runoff , heavy metals , phytofilter , phytoregeneration , rain gardens