There are five components to the tank cleaning system: � Chemistry: � Proprietary surfactant package (an additive that reduces the wash-water's surface tension and increases its spreading and wetting properties) � Wash-water recycling (around � Control centre � Primary/secondary solids separation � Pressure pumps (supply) � Slop pumps (return) � Stationary tank cleaning machines: � Quad pods with magnetic feet � High-pressure hydraulic jets: � 360-degree jets for full tank coverage � 180-degree jets down to concentrate on the tank bottoms.