The Kennedy/Jenks project that used biochar as part of a stormwater filter in a busy log yard for the Port of Tacoma was a winner of the American Association of Port Authorities 2014 Environmental Improvement Award.
http://www.aapa-ports.org/Programs/content.cfm?ItemNumber=19926&RDtoken=...
In this project they are using a chain of filters working together, that includes sand filteration, a sand and biochar combination and finish with biofilters for phytoremediation. They've had some impressive results: 92% reduction in Zinc, 81% reduction in copper, 94% reduced turbidity, and 85% reduced suspended solids. Biochar is a small part of the total project, but it shows the potential for using biochar as component in filteration media that can improve the system as a whole.