Abstract: A box culvert assembly and method of forming a box culvert assembly is provided. The boxes forming the assembly comprise portions configured to allow pivoted assembly of one box into another, while reducing the likelihood of high stress or fracture. The box assembly further allows for a generally tight seal between the boxes.

Abstract: A box security cover comprising a box cover and a locking assembly. The box security cover can be positioned on a box, and the locking assembly can move between an unlocked position in which the security cover can be removed and a locked position in which braces of the locking assembly can contact interior surfaces of the box, preventing removal of the security cover from the box.

Abstract: A liquid purification and separation apparatus for separation of pollutants in stormwater runoff is disclosed. This apparatus utilizes gravitational separation and tortuosity, resulting from a plurality of baffles both perpendicular to and oblique to the primary water flow direction, to trap substances less-dense and more-dense than water. The apparatus features improved resistance to pollutant remobilization through treatment of water volume rather than flow rates, using vertically stacked water columns of varying depths to settle small particles. An overflow structure diverts excessive liquid without interfering with purification and separation, and can be placed integrally within or external to the apparatus receptacle.