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Controlling the Influent Load to Wastewater Treatment Plants

Bolmstedt, Jon LU (2004)
Abstract
The need for control of the influent load to a wastewater treatment plant

(WWTP) is becoming more important. One reason for this is that there are

a number of things that cannot be achieved with plant-focused control. For

instance it is hard to avoid sludge loss as a result of poor settling or

reducing a too high influent flow rate by in-plant control actions. It is also

difficult to reduce the effects of a toxin in the influent, if the entire influent

is to be biologically treated. Optimisation of the various parts of the

collection system, with respect to locally defined objectives, may be

counter-productive as it may increase the effluent loads when taking... (More)
The need for control of the influent load to a wastewater treatment plant

(WWTP) is becoming more important. One reason for this is that there are

a number of things that cannot be achieved with plant-focused control. For

instance it is hard to avoid sludge loss as a result of poor settling or

reducing a too high influent flow rate by in-plant control actions. It is also

difficult to reduce the effects of a toxin in the influent, if the entire influent

is to be biologically treated. Optimisation of the various parts of the

collection system, with respect to locally defined objectives, may be

counter-productive as it may increase the effluent loads when taking the

whole system into account. This is typically the case as optimisation of the

control of the sewer net with respect to combined sewer overflows (CSOs)

leads to an increased flow to the WWTP. Equalization basins are used to

control the flow rate or the load in the sewer net as well as at the WWTPs.

The focus has recently been shifted from only reducing the amount of

CSOs to reduce the effluent load from the sewer and the WWTP. To

minimize the total load from the system the methods previously used to

optimise the individual sub-systems must be used together and information

from various parts of the system should be available system wide.

Due to the cost associated with the construction of equalization basins, the

current approach is to increase storage volume by constructing and

controlling gates in the sewer net. The potential of system wide control is

difficult to estimate, which is exemplified by a discussion on some existing

implementations. In this thesis an equalization basin is modelled and used

with an existing model of a WWTP. This system is operated with some

commonly applied control strategies of equalization basins to estimate the

result of control during ideal conditions. Without control of the basin, the

possible benefit of construction, or providing an equal amount of storage

capacity in the sewer net, is evaluated. (Less)
Please use this url to cite or link to this publication:
author
supervisor
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type
Thesis
publication status
published
subject
pages
124 pages
publisher
Department of Industrial Electrical Engineering and Automation, Lund Institute of Technology
ISBN
91-88934-33-0
language
English
LU publication?
yes
id
d718f57a-c9f4-42fd-9f07-77c15252de16 (old id 587918)
alternative location
http://www.iea.lth.se/publications/Theses/LTH-IEA-1040.pdf
date added to LUP
2007-10-30 09:30:54
date last changed
2016-09-19 08:45:08
@misc{d718f57a-c9f4-42fd-9f07-77c15252de16,
  abstract     = {The need for control of the influent load to a wastewater treatment plant<br/><br>
(WWTP) is becoming more important. One reason for this is that there are<br/><br>
a number of things that cannot be achieved with plant-focused control. For<br/><br>
instance it is hard to avoid sludge loss as a result of poor settling or<br/><br>
reducing a too high influent flow rate by in-plant control actions. It is also<br/><br>
difficult to reduce the effects of a toxin in the influent, if the entire influent<br/><br>
is to be biologically treated. Optimisation of the various parts of the<br/><br>
collection system, with respect to locally defined objectives, may be<br/><br>
counter-productive as it may increase the effluent loads when taking the<br/><br>
whole system into account. This is typically the case as optimisation of the<br/><br>
control of the sewer net with respect to combined sewer overflows (CSOs)<br/><br>
leads to an increased flow to the WWTP. Equalization basins are used to<br/><br>
control the flow rate or the load in the sewer net as well as at the WWTPs.<br/><br>
The focus has recently been shifted from only reducing the amount of<br/><br>
CSOs to reduce the effluent load from the sewer and the WWTP. To<br/><br>
minimize the total load from the system the methods previously used to<br/><br>
optimise the individual sub-systems must be used together and information<br/><br>
from various parts of the system should be available system wide.<br/><br>
Due to the cost associated with the construction of equalization basins, the<br/><br>
current approach is to increase storage volume by constructing and<br/><br>
controlling gates in the sewer net. The potential of system wide control is<br/><br>
difficult to estimate, which is exemplified by a discussion on some existing<br/><br>
implementations. In this thesis an equalization basin is modelled and used<br/><br>
with an existing model of a WWTP. This system is operated with some<br/><br>
commonly applied control strategies of equalization basins to estimate the<br/><br>
result of control during ideal conditions. Without control of the basin, the<br/><br>
possible benefit of construction, or providing an equal amount of storage<br/><br>
capacity in the sewer net, is evaluated.},
  author       = {Bolmstedt, Jon},
  isbn         = {91-88934-33-0},
  language     = {eng},
  note         = {Licentiate Thesis},
  pages        = {124},
  publisher    = {Department of Industrial Electrical Engineering and Automation, Lund Institute of Technology},
  title        = {Controlling the Influent Load to Wastewater Treatment Plants},
  year         = {2004},
}