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