7 gravity settlers for liquid and solids separation for industrial and municipal use; machines for de-watering and compressing solids which have been screened from a wastewater stream; machine parts, namely, moving aeration chains made of a hose and floating assembly which support certain apparatuses, namely, fine bubble diffusers, air piping manifold, blowers, partition walls, sludge removers, rakes and overflow weirs to provide mixing and aeration in biological treatment wastewater systems