{HEAD ~ A process} in accordance 1 or 2 further including {TAIL ~ the step} of ozonizing the water to be purified prior to said percolating step 
including
{ HEAD ~ A process } in accordance 1 or 2 further including { TAIL ~ the step } of ozonizing the water to be purified prior to said percolating step
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH