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Features
·
Guaranteed Longest Lasting
Sensors Available with performance guarantee *
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Sensors are compatible with most
existing pH/ORP Meters, Transmitters & Analyzers **
·
Application Specific Engineering
results in optimum Lifetime & Performance ***
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Integrated Temperature
Compensation, Preamplifiers & Solution Ground Elements
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Solid State Reference System offers superior resistance to Fouling
& Dehydration
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Applications such as Acid/Fluoride,
Hi-Temp, Saturated Sodium and Sulfide Resistant are available as standard
options
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Custom Applications are available,
often at no additional charge
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Most Installation Styles are
Supported Including: Immersion, Twist Lock, Valve Retractable
& Sanitary
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Available in a wide range of plastics,
from cost effective CPVC to thermally & chemically resilient ULTEM®
and PEEK thermoplastic
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High Pressure Applications up to
100 psi for Valve Retractable & 150 psi for Inline Installations can be
supported for continuous use
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Operating Temperatures from -30
to +150 ºC (-22 to +302 ºF) can be supported
for continuous use
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Case
Study No. 17
Measurement of Ammonia and Nitrate in Municipal
Wastewater for control of Nitrification and Denitrification Treatment Process
Advantages
of the Advanced Sensor Technology real-time continuous online measurement
systems for ammonia and nitrate
Low Initial
Procurement Cost compared to competing technologies and offerings
No need for
chemical feed and rebuilding of sensors
Lower Cost of Ownership
due to very long sensor lifetime, low maintenance & cleaning requirements
for inline, immersion & submersion ion selective sensors
Intuitive and
easy to use Rosemount 1056 and 1057 analyzer programmed and configured for
ammonia and nitrate ion selective analysis
All new systems
come preconfigured, precalibrated and fully qualified to install, plug-in and
immediately place into service especially for
compliance purposes
Only periodic
1-point grab sample offsetting is required – this “Standardize” calibration
can be performed WITHOUT removing sensor from service!
The
Problem
A number of municipal
wastewater plants are now using a variety of nitirification and
denitrification type wastewater treatment systems to comply with various
environmental and discharge limits (such as NPDES permits). The nitrification and denitrification
process used can start with a number of nitrogen sources, but the simplified
inorganic oxidation and reduction reaction sequence is commonly written as
Ammonia (NH3-N)> Nitrite (NO2-) >
Nitrate (NO3-) > Nitrogen N2 (off gas). Until now, the technologies to measure the
two nitrogen species of greatest interest in such plants (starting ammonia
and the oxidized product nitrate) have been only possible with expensive
sampling analyzers that required reagents, and significant operator
involvement to ensure nominal operation.
The result has been the operator and time intensive method of periodic
grab sampling to ensure that both the nitrification and denitrification
systems are working within the appropriate limits continues to be used at most facilities.
Process upsets due to the nitrogen load changing from the incoming
wastewater or due to equipment malfunction can result in significant problems
such as high nitrate discharges that can lead to problems with permits and
other environmental issues. This issue
can be particularly problematic with smaller and remote facilities that have
less frequent operator presence due to personnel limitations. Often plants will have existing pH, ORP and
DO measurement online to control the level of ammonia conversion to nitrate,
and to define the period of anaerobic conversion of the nitrate to nitrogen
off-gas. Although these processes are
pH dependent, often this is not a critical control parameter due to the
process pH stability (particular for larger systems). In some cases the ORP (oxidation reduction
potential) can act a proxy for the ammonia/nitrate ratios in solution. Although ORP can sometimes serve as a good
first order approximation for this ratio, it is highly dependent upon other
components in the water and is very sensitive to pH and temperature. Lastly, since ORP is a ratio only
measurement it does not provide any information about the ABSOLUTE
concentration of neither ammonia nor nitrate.
The
Solution
A dual or triple channel analyzer to continuously measure any of the
following species of interest: ammonia a.k.a. NH3-N or total
nitrogen (in the ionized ammonium form at most wastewater pH), nitrate, pH
and ORP. The dual and triple channel
configuration makes the measurement very cost effective with the most common
configurations being dual channel ammonium and pH and triple channel
ammonium, pH and nitrate although other combinations are possible as
well. The ability to measure in
particular ammonia and nitrate online in real time with minimal calibration
and cleaning requirements makes it possible to record and control the process
between grab samples. Since the
conversion of dissolved ammonia gas to the ionized ammonium form is a pH and
temperature dependent process, ASTI offers the ability for this pH and
temperature compensation to be performed in real-time to yield information
about the total amount of free ammonia that is present (see below).
The online ion selective
measurement system can be calibrated for 1-point offset without removing the
sensor from service, making it ideal for low maintenance continuous use. The online ion selective measurement
systems for ammonia and nitrate can readily be reference to most any grab
sampling laboratory or portable method (including the popular colorimetric
kits and existing sampling analyzers).
Two-point calibrations need only be performed for new sensors in most
cases once again minimizing the service and commissioning requirements. These ISE systems are available for a wide
variety of installation styles and can be integrated into any modern PLC and
DCS system. Sensors are available with
a variety of options including preamplifiers for long cable lengths to 300
feet and fully submersible assemblies to interface with any process
connections and configurations.
SENSORS USED FOR
MEASUREMENT
Sensors for in Tank Installations
with Standpipe for Immersion or Submersion (with waterproofing option) – 3/4”-
1” MNPT Immersion Sensor Body Configurations
Model: AB 6410-1000-10-TL Ammonium Ion Selective Sensor
Description: Ammonium Ion Selective Sensor with 1000 Ohm
Platinum Temperature Compensation Element; 10 feet cable to connect directly
to 1056 or 1056 ISE Analyzers
Model: AB 6810-1000-10-TL Nitrate Ion Selective Sensor
Description: Nitrate Ion Selective Sensor with 1000 Ohm Platinum
Temperature Compensation Element; 10 feet cable to connect directly to 1056
or 1056 ISE Analyzers
Model: PNZ 6052-1000-10-TL pH Sensor
Description: Industrial pH Sensor with 1000 Ohm Platinum
Temperature Compensation Element; 10 feet cable to connect directly to 1056
or 1056 ISE Analyzers
Sensors for Inline Installations
with Quick Disconnect Bayonet Style Fittings
- 1”
MNPT Twist Lock Quick Disconnect Sensor Body Configurations
Model: AB 8410-1000-10-TL Ammonium Ion Selective Sensor
Description: Ammonium Ion Selective Sensor with 1000 Ohm
Platinum Temperature Compensation Element; 10 feet cable to connect directly
to 1056 or 1056 ISE Analyzers
Model: AB 8810-1000-10-TL Nitrate Ion Selective Sensor
Description: Nitrate Ion Selective Sensor with 1000 Ohm Platinum
Temperature Compensation Element; 10 feet cable to connect directly to 1056
or 1056 ISE Analyzers
Model: PNZ 8052-1000-10-TL pH Sensor
Description: Industrial pH Sensor with 1000 Ohm Platinum
Temperature Compensation Element; 10 feet cable to connect directly to 1056
or 1056 ISE Analyzers
ANALYZERS USED FOR
MEASUREMENT
Model: 1056-XX-22ISE-32-YY (Ammonium / pH)
Description: Dual Channel Ammonium & pH Analyzer, Transmitter and
Controller
Model: 1057-XX-22ISED-32-42ISED (Ammonium / Nitrate
/ pH)
Description: Triple Channel Ammonium, Nitrate and pH Analyzer,
Transmitter and Controller
XX is the power supply option and YY is
the output option (for 1057 only 4 each 4-20 mA output is available). ISE configuration must be specified at time
of order. Complete ISE systems only
available directly from ASTI as complete online measurement systems.
Ion selective sensors are NOT available for sale without ISE analyzer
as provided by ASTI. Application must be validated by ASTI factory prior to
sale. References are available upon
request.
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