City of Frisco Engineering Standards

Engineering Standards
5.2.9 Inverted Siphons
The use of an inverted siphon to avoid obstructions along the alignment of the wastewater main
requires approval by the Director of Engineering Services. Should an inverted siphon be necessary
the design shall include:
A. Two or more barrels (pipes).
B. A minimum pipe diameter of 6”.
C. The necessary appurtenances for convenient flushing and maintenance.
D. One upstream and one downstream of a manhole for cleaning equipment, inspection and flushing.
E. The siphon must be sized with sufficient head to achieve velocity of at least 3 fps at initial and
design flows.
F. The inlet and outlet shall divert the normal flow to one barrel.
G. The system shall be designed to allow any barrel to be taken out of service for cleaning.
H. The system shall be designed to minimize nuisance odors.
5.2.10 Wastewater Lift Stations
Subdivisions shall be laid out so that all wastewater mains will be gravity flow. The use of a
wastewater lift station must be approved by the Director of Engineering Services and the Director of
Public Works.
A. All wastewater lift stations shall be designed in accordance with TCEQ Chapter 217, Subchapter
C.
B. The Engineer shall prepare an engineering design report for the wastewater lift station.
C. The lift station shall be connected to the City Supervisory Control and Data Acquisition
(SCADA) system. The Owner shall pay all costs associated with the SCADA including all labor,
equipment, materials, and programming of the City’s computer and testing. The SCADA
equipment installed shall conform to the City’s standard specifications for Computerized
Monitoring and Control Specifications for Wastewater Lift Stations.
D. Control panels shall have heaters and exhaust fans, CT for reading amperage, HOA switch, and
an amp overload reset button on the outside of the panel.
E. All lift stations shall include a bioxide injection system for odor control.
F. The bioxide tank shall have a concrete foundation.
G.
If carbon filters are required, the housing shall be painted per the approval of the Director of
Engineering Services.
H. Lift stations with two or more wet wells shall include a sluice gate between each wet well.
I. Each pump shall have two guide rails.
Section 5 – Water & Wastewater Design Requirements May 2012 Page 5-14