ensure that filtered solids were flushed from the housing prior to filter dissolution and important factor where loadings could cause blockage of tubing and valves test conditions included a flow rate of 100 ml min recirculation 1 6 gal min and 10m hno 3 solvent at 160 u00b0 f under continuous recirculation the total system volume was 2 5 liters a second test was identical to the first except the filter was loaded with 177 g dry weight of susquehanna river silt the average loading of actual tmi waste filters the results of both tests indicate that this type of filter cartridge can be dissolved in situ in approximately 2 3 hours under the conditions previously stated a total of 7 liters of 10m hno 3 three reservoir fillings and 2 liters of h 2 o rinse was used in test 1 the entire filter dissolved and was pumped into the reservoir without plugging or noticeable back pressure on the system the resultant waste solution was brown in color and contained an organic scum which continued to digest after the solution was allowed to cool total duration of the test was 5 hours the second test using silt loaded filter was quite similar to the first except that the silt was rapidly backwashed to the reservoir creating a murky acid solution less organic scum was observed on the reservoir surface during this test after two hours a three way valve was switched to direct flow into the bottom of the filter housing this caused an additional burst of silt which restricted flow to the reservoir.