ABSTRACT
The atmosphere in both Septic Tank Effluent Pumping (STEP) and grinder pump pressurization units can be very corrosive. It is incumbent upon the engineer to utilize materials that are capable of withstanding this atmosphere. Consideration must also be given to pumping out the pressurization unit for STEP systems, and the pressurization unit should therefore be located in such a position that it can be pumped out. Grinder pump systems are generally packaged in such a manner that these considerations have been incorporated at the factory. STEP systems, however, are often designed and fabricated locally; therefore, these considerations must be included in the design. Emergency overflow in STEP interceptor tanks should contain 24 hours of flow, and this usually is a function of the design of the interceptor tank. An advantage of the STEP system concept over the grinder pump system is the additional storage capacity available.
