1 March 1997
1-1. PURPOSE AND SCOPE. This document provides information, guidance, instructions, and
criteria for the design of sanitary and industrial wastewater gravity collection systems and
a. Sewers. This document prescribes the approach, requirements, criteria, considerations,
and hydraulic calculations used in the design of gravity sewers. Acceptable materials and
appurtenances are also presented. Alternatives to gravity systems are described, but design
criteria is not given.
b. Pumping Stations. Facilities covered in these instructions include pump and ejector
stations required for (1) removal of sanitary and industrial wastes from remote or low lying areas
of sewers, (2) controlled introduction and lifting of raw wastewater into the waste treatment plant,
(3) transfer of recycled and bypassed flows throughout the plant, and (4) discharge of treated
scum; these facilities are presented in TM 5-814-3/AFM 88-11, Vol. 3. The design of a
wastewater pumping station will typically include site improvements, structures, screening, and
flow monitoring devices, pumping units, pump drives, system controls and instrumentation,
mechanical and electrical components, interior piping, underground force mains, valves, and
appurtenances. Small grinder pumps such as those used in low pressure systems are not
included in this manual.
1-2. APPLICABILITY. These instructions are applicable to all USACE elements who plan and
design wastewater facilities at fixed Army and Air Force installations.
1-3. REFERENCES. Appendix A contains a list of references used in these instructions.
1-4. DESIGN OBJECTIVES. The design of a sewer system must provide an engineered system
of sewers and pump stations, complete with all appurtenant facilities, sufficient in size and
capacity to collect and convey the required wastewater flows to an acceptable point of discharge.
The system must be practicable, economically feasible, and all components must be located to
minimize the costs of installation, operation, and maintenance. Sewers and appurtenances must
be structurally sound, and must protect the environment from pollution caused by leakage or
overflows. Extraneous flows that hydraulically overload the system and produce flooding at
sewer manholes and lift stations must be excluded. Elimination of excessive infiltration and
inflow is essential in avoiding increased costs of sewer maintenance, wastewater pumping, and
treatment. Eliminating or minimizing conditions that lead to microbiological induced corrosion
and other deterioration of the systems will reduce maintenance and repair costs. Even more
important in this regard is the necessity to maintain design wastewater treatment efficiencies,
and thus assure that effluent discharge requirements are met.
1-5. SPECIAL WASTES. Contributing waste flows which are harmful to sewer pipe materials,
pumps, and appurtenant structures, toxic to biological and other waste treatment systems, or
create fire and explosion hazards or a safety hazard to personnel, must be identified and
evaluated early during predesign, so that suitable materials and/or procedures for their disposal
can be included. Systems for hazardous and explosive wastes, corrosive acids or alkalies, high
temperature or other industrial type wastes, will generally require the selection of highly resistant