Sewer overflow discharge monitoring system and method
A method and a system for monitoring the performance of combined sewer overflow structures is described. The inventive system includes sensors for monitoring the level of sewage in the structure and the operation of valves. A data processing unit collects data and calculates the flow of an overflow event and/or the performance of gate valves. The system may be battery operated and may adaptively change the sensor sampling time to prolong battery lifetime.
1. A warning system that warns when sewage gate is not operating properly, said system comprising:
an upstream sensor for measuring an upstream liquid height at a location upstream from sewage gate;
a downstream sensor for measuring an downstream liquid height at a location downstream from sewage gate;
a gate sensor for providing an indication of an actual degree of opening of sewage gate; and
a processor for processing code;
memory, coupled to said processor, for storing code to be executed by said processor; and
wherein said processor operative to perform the functions of:
receiving data from said upstream, downstream and gate sensors at one or more instances in time, wherein said data from said gate sensor allows computation of actual degree of opening of sewage gate at one or more instances in time;
deducing, using said data received from said upstream and said downstream sensors, a theoretical degree of opening of sewage gate at one of said one or more instances in time, and wherein said theoretical degree of opening “δ” is solved from:
(
∂
gB
g
6
cos
(
δ
)
)
(
3
L
g
2
(
h
0
-
h
2
)
cos
2
(
δ
)
+
(
L
g
-
h
0
)
3
-
(
L
g
-
h
2
)
3
)
-
L
g
2
mg
sin
(
δ
)
=
0
wherein “B g ” is the gate width, “g” is gravity, “L g ” is a gate length, “h 0 ” is a liquid height above a weir crest at said upstream sewer location, and “h 2 ” is a liquid height above said weir crest at said downstream sewer location;
determining, at one of said one or more instances in time, a difference between said theoretical degree of opening of sewage gate and said actual degree of opening of said sewage gate to arrive at a gate opening deviation; and
providing a warning that sewage gate is not operating properly when said gate opening deviation is greater than a predetermined amount.
2. The system of claim 1 , wherein said system includes a telemetry system that reports if sewage gate is not operating properly.
3. The system of claim 1 , wherein said processor further operative to perform the functions of:
instructing transmission of power, after a first time duration, to said sensors to allow said sensors to take measurements and acquire said received data;
determining, after lapse of said first time duration and using said received data, if overflow conditions exist;
repeating said instructing and said determining after lapse of a second time duration, which is shorter than said first time duration, if said overflow conditions exist; and
repeating said instructing and said determining after lapse of said first time duration, if said overflow conditions do not exist.
4. The system of claim 1 , wherein said system includes a telemetry system that transmits said data in real time to utility staff or another processor.
5. The system of claim 1 , wherein said system adjusts a rate at which said data is sampled by said data processing device.
6. The system of claim 1 , wherein said system is powered by one or more batteries.
7. The system of claim 1 , further comprising a flow meter upstream gates, wherein said flow meter is used to calibrate for flow momentum.
8. The system of claim 1 , further comprising a flow meter downstream of sewage gate, wherein said flow meter is used to calibrate a discharge coefficient of sewage gate.