Multiple Compartment Tanks

Tanks with multiple compartments shall be required as specified in 310 CMR 15.223(1). When multiple compartment tanks are used the following shall be required: (1) The number of compartments shall not exceed two; (2) The first compartment shall be sized for a minimum hydraulic detention time of 48 hours based on the design flow; (3) The second compartment shall be sized for a minimum hydraulic detention time of 24 hours based on the design flow; (4) The compartments shall be interconnected by a minimum four inch vented, inverted U-shaped pipe which extends below the bottom of the scum layer; and (5) The outlet tee of each compartment shall be equipped with a corrosion resistant gas baffle or a Department approved effluent tee filter.