I would be pretty concerned about industrial contamination. I'm not sure any technique is guaranteed to remove the huge variety of junk that gets dumped down storm drains in industrial areas. I would consider that water source to be suspect.

A better approach might be to find clean water within the industrial district. There could be some in certain storage tanks, flushing reservoirs, water pipes, gutters on roofs etc. You might be better to scrounge around ... but look for pure water.

other Pete