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Sequencing Batch Reactor for Leachate Treatment
Waste
Management, Inc. is the leading provider of comprehensive
waste and environmental services in North America. Part of
their business involves responsibly managing landfills, such
as the Mountain View Reclamation Facility in Greencastle, PA.
Liquid that drains from a landfill, call leachate, must be
properly treated before it can be discharged to municipal
water treatment systems or back into the environment.
Aegis Solutions designed,
built, and deployed a SCADA system that is being used to
monitor and control leachate treatment at Waste Management’s
Mountain View Reclamation facility.
Since the
original deployment of the SBR System, significant upgrades
and expansions have taken place to handle the growth of the
landfill.
The
Mountain View SBR System presently consists of three
equalization tanks (500,000, 750,000, and 1 million gallons),
a 250,000 SBR tank, and additional smaller tanks for biowaste
storage and pre-discharge storage. Within the EQ and SBR tanks
are mixers, aerators, and sensors for dissolved oxygen, pH,
oxidation-reduction potential, temperature, and tank level.
Additionally, there is a network of pumps for moving material
between the tanks and flow meters for measuring how much
material has been transferred.
Aegis
Solutions
used National Instruments Fieldpoint communication controllers
and input/output modules as the hardware platform for the
three control panels of the SBR System. Each panel has a
combination of analog and discrete inputs, discrete outputs,
and relays to provide all sensors monitoring, status feedback,
and control required for operating the SBR System.
Each
control panel is connected to an RS-485 communications
network along with a computer, located in the laboratory at
the Mountain View facility.
Aegis Solutions used National Instruments
Lookout HMI/SCADA software system to program the SBR System
for control, monitoring, and operation.
The
software provides a graphical representation of the SBR
System and continuously displays real time measurements
from the system sensors and status feedbacks, so the plant
operator always knows the state of the plant. From the
main screen, the operator can drill down to screens for
each tank to see a detailed view of the parameters and
exercise manual control of the mixers, aerators, and pumps.
The SBR
System software is feature rich. It provides a Trending
Screen which graphs all sensors, pump actuations, and
status feedbacks. The trending graph allows the operator
to go back to any period of time and see the status of the
process and system. In addition, all measurements and
control states are recorded to a Microsoft Excel worksheet,
so the user can use external applications to analyze data.
The interval for data recording and trending can be
configured by the user. Since most SBR processes need to
run for 24 hours, it was critical that the system be
capable of running user defined “recipes” unattended.
Aegis Solutions
implemented a method that allows users to create “recipes”
using Microsoft Excel, which the SBR System software can
load and execute. This feature saves Waste Management the
cost of manning the plant to process leachate during the
night.
Finally,
the SBR System was setup to provide remote access for users
who are offsite. This feature allows them to remotely
check the system status, respond to alarms, and operate the
controls. The remote access feature also allows
Aegis Solutions to
remotely support the SBR System and quickly respond to any
needed changes.
Using
Engineering and Technology to Keep the Environment Clean
Understanding the client’s needs and requirements and good
engineering allowed Aegis
Solutions to provide a cost-effective control
system that helps Waste Management meet all state and local
standards for leachate treatment and keep the local
environment clean.
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