Abstract: A system for covering liquids stored within an open-topped liquid storage tank having a peripheral wall has a cover for extending across at least a portion of stored liquids, and two or more guide assemblies spaced about the peripheral wall for securing the cover to the peripheral wall and for permitting the cover to freely travel substantially vertically up and down within the interior space. Each assembly has a vertical guide, a clamping member, and an upper and a lower delimiting stop. The cover can be operatively secured to the assembly by a restraining tether.

Abstract: A storage tank system stores liquid containing debris. The sidewalls of the tank have a curved lower portion for receiving debris settling out of the liquid and for directing at least some of the debris to a base of the tank. The tank is also provided with a plurality of nozzles spaced longitudinally along the curved lower portion the sidewalls for directing flush liquid downwardly against the curved lower portion for flushing any residual debris remaining thereon towards the bottom of the tank. The tank has a skid equipped with rollers for improved manoeuvrability in a berm environment and manifolds for improved interconnectability with other tanks.