The construction of industrial digesters must comply with the toughest construction conditions. The temperature in the tanks can vary between ambient temperature and 35°C or 95°F (mesophilic) to 60°C or 140°F (thermophilic); and this with ambient temperatures to -15°C or 5°F. Often the digesters have a reinforced concrete or STAINLESS STEEL roof. In the upper part of the wall and the inner side of the roof a lining is adhered to the form work and poured in the concrete. Afterwards the lining is welded and tested against leakage. The composition of the soil will determine if pile foundations or standard foundations are required. Bio-Dynamics has an extensive reference list of UASB-reactors (Upflow Anaerobic Sludge Blanket) and digesters upon request.