such as seen in fig5 may be fitted with a variable orifice discharge port such as a valve assembly 52 having an extended actuator rod and handle as further detailed in fig8 however the adjustable orifice or valve assembly 52 may be attached directly to the discharge outlet 46 of the grinder pump 44 the valve assembly 52 is usually controlled from the upper deck 32 it is important to understand the need to reduce the discharged orifice size of the pump by up to 50 percent to insure sufficient grinding residence within the grinder pump 44 float assembly 54 attached to the cuttings hood 24 may automatically control the level of slurry 42 in the slurry tank 38 as previously mentioned the filter screen assembly 48 may be made rotatable as shown in detail in fig6 in this case a hollow shaft gear reducer assembly 56 is mounted to the make up tank side of the partition wall 39 and driven by either a pneumatic hydraulic or electric gear motor 58 a tubular shaft 64 with a plurality of holes 60 therein is inserted through the hollow shaft portion of the gear reducer 62 and secured therein the linear screen assembly 48 is.