In Step 23, {HEAD ~ the pumping} of {TAIL ~ the solution} and the discharging of the liquid are controlled to optimum rates 
of
In Step 23 , { HEAD ~ the pumping } of { TAIL ~ the solution } and the discharging of the liquid are controlled to optimum rates
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH