Page 19 - Sept/Oct 2018 Vol 36 No 3

wastewater to the collection system for treatment during times EQ System Overview
of normal flow. The collection system rehabilitation program, EQ Control
ongoing since the late 1990s, is to be continued in an effort to System
further reduce I&I.

Design challenges

The overarching challenge in this project was designing the
entire EQ system to work as one – that meant designing a system
that would total the flow from the three interceptor sewers
contributing flow to the main interceptor at the junction and use
the total flow rate to control the basin operational scheme.

Another challenge involved the Emory Valley drainage basin.
There are three different force mains coming into the basin;
designing a pipe and valve system to control the flows on those
force mains required a complex, intricate design. With the
Scarboro basin, modeling was used to determine a maximum
flow that the downstream interceptor could handle during times
of peak flows and then a splitter box with an adjustable weir was
designed to divert excess flow into the EQ Basin.

In the case of the East Plant EQ Basin, the engineering team
took advantage of a slot for a future third pump in the existing
pump station to pump excess flow to the EQ Basin based on
the liquid level in the pump station wet well. The East Plant EQ
system was also designed to work independently of the overall
system to reduce overflows at the station.

Instrumentation and controls

As part of the effort to meet the objective of controlling the
rate of flow being discharged to the main interceptor, Glenn
Hanson, P.E., Electrical I & C Engineer with LDA, designed a
control system where instrumentation and programmable logic

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