The biofiltration technology was developed by Monash University in Australia, and the pilot project in Kfar-Saba is testing the technology in the Israeli environment under local conditions. The Kfar-Saba biofilter, along with parallel pilot projects in Ramla and Bat-Yam, will provide the knowledge and experience needed to help create legislation and regulations that will advance the water sensitive city approach on a nationwide basis throughout Israel.
The biofilter covers an area of 87 square meters. It is fully lined and has five layers of filter media, totalling 1.2 meters in depth. The bottom layer is permanently submerged and is enhanced with a cellulose-based carbon source to ensure effective denitrification (removal of nitrates). The top layer of the biofilter is free-draining loamy-sand (locally sourced) which supports plant growth and aerobic treatment processes. The biofilter system includes twelve different types of plants, of which 50% are Australian species that are excellent for pollutant removal while maintaining the filtration capacity of the system (de-clogging).
The designed infiltration rate is between 300 and 400 mm/hr.
Urban runoff is brought to the biofilter surface by gravity. In the winter, water from contaminated groundwater wells is pumped into the system. The polluted water then filters by gravity through the matrix of the media and plants, and pollutants are removed by a number of bi-physical processes. The system is effective in removal of suspended solids, heavy metals, nutrients (nitrogen and phosphorus) and oils. The treated water is collected by perforated pipes at the bottom and conveyed to the recharge wells.
