The open steel tank stores service water, slurry and digestate at agricultural, municipal and industrial sites. The required capacity is determined by liquid inflow and consumption, removal intervals and the storage reserve needed. The tank operates at atmospheric pressure. Its purpose is to store the selected liquid; the design is matched to the composition of that liquid and the conditions at the installation site.

The shell consists of glass-fused-to-steel panels, known as GFS. The enamel forms a smooth protective layer that separates the steel from the stored liquid. The coating is specified for a pH range of 3–11; suitability for a particular liquid is checked against its composition, temperature and contact time. Bolted joints are sealed with sealant. The coating, edge treatment and joint sealing together provide the shell's protective system.

Factory-made panels are delivered as separate components and assembled in circular courses on site. This allows a large tank to be transported without shipping a complete vessel. The main panel joints are bolted, with no on-site welding of the wall. The shell includes the necessary stiffeners and its connection to the concrete base. Plate thicknesses, reinforcement and fixings are designed for the selected diameter and height.

Two flanged nozzles are provided: one inlet and one outlet. Both are DN100 for tanks below 2,000 m³, DN150 from 2,000 to 4,200 m³ inclusive, and DN200 above 4,200 and up to 10,000 m³. Connection elevations and orientation are agreed before panel manufacture. External pipework, pumps and shut-off valves are selected separately. The number of pipe connections remains the same throughout the range: two flanged nozzles.

The materials package includes enamelled shell panels, structural rings and stiffeners, bolts, nuts, washers, protective caps and sealants. The bottom connection and foundation fixings secure the wall to its base as designed. Two flanged nozzles handle filling and discharge, and a 750 mm service manhole provides access for inspection and cleaning of the emptied tank. The scope is common to all sizes; shell dimensions, reinforcement and nozzle sizes vary with capacity.

The tank is installed on a reinforced concrete base with a watertight floor. Fixing elevations and positions are coordinated with the foundation design before construction. Service water storage is sized for the required reserve and withdrawal pattern; slurry and digestate also require consideration of solids content and possible sediment. Working capacity, emptying intervals and cleaning requirements follow the storage duty. Liquid temperature depends on operating and ambient conditions.

For every size, the liquid and wind loads, stability of the open upper course, panel thicknesses and anchorage are checked. The matrix supports capacity selection; the final design requires site-specific structural verification. After assembly, the coating, joint tightening and shell watertightness are checked. Concrete works, foundations, delivery and installation are excluded from the tank materials package.