oEPA
www.epa.gov
TECH
•"nvironmental Technology Verification Program
On-line Wastewater Nutrient Monitoring
Identifying and testing continuous monitoring technologies to
track and control nutrients in source and product waters, includ-
ing treated effluents, is important to achieving further reduction
of nutrients in the aquatic environment. In 2005, the U.S. EPA
Environmental Technology Verification (ETV) Program's Ad-
vanced Monitoring Systems (AMS) Center, operated by Battelle
under a cooperative agreement with EPA, verified the perform-
ance of two nutrient monitors at an industrial waste water treat-
ment facility (see Table I)1. One technology measured nitrate
only, with results expressed as total nitrogen. The other technol-
ogy measured total nitrogen and total phosphorus. Additional
testing of nitrate monitoring technologies is being planned un-
der the AMS Center for environmental applications for measur-
ing nutrients in ground water.
Verification Testing Description
In 2005, the ETV Program conducted verification testing for 42
consecutive days at an industrial wastewater treatment facility
in Richmond, VA. The final outfall flows into the James River.
Accuracy, bias, linearity, limit of detection (LOD), reproduci-
bility, span and zero drift, matrix effects, data completeness,
and operational factors were determined. On-line monitoring
results were compared to results obtained from water samples
analyzed using Standard Methods for the Examination of Water
and Wastewater, 18th Edition (APHA, 1992). During off-line
testing, the technologies were challenged with multi-level nutri-
ent standards and deionized (DI) water for total nitrogen (TN)
and total phosphorus (TP) to determine LOD, percent recovery, and other performance metrics. In the off-line test-
ing, the technologies were also challenged with additional nutrient standards for the determination of accuracy for
several forms of nitrogen and phosphorus. Table 1 provides a description of the nutrient monitoring technologies
included in the test. Selected performance data are available in Table 2, and detailed performance data are available
in the verification reports for each technology at http://www.epa.gov/nrmrl/std/etv/vt-ams.htmlfamtfia.
Nitrogen and Phosphorus
Pollution at a Glance
High levels of nitrogen and phosphorus, or nutri-
ent pollution, in bodies of water result in harmful
algal blooms, reduced spawning grounds and nurs-
ery habitats, fish kills, and oxygen-starved hy-
poxic or "dead" zones. This can be a public health
concern since this process can lead to impairment
of drinking water sources and increased exposure
to toxic microbes such as cyanobacteria.
EPA and states have identified high nutrient load-
ing as the leading cause of pollution in lakes, res-
ervoirs, and ponds. Almost every U.S. state and
territory has been impacted by nutrient-related
degradation of the country's waterways. All but
one state and two territories have Clean Water Act
Section 303(d) listed impairments for nutrient pol-
lution. States have listed over 10,000 nutrient and
nutrient-related impairments. Fifteen states have
more than 200 nutrient-related listings each (EPA,
2002). For these reasons, EPA regional offices
have identified nutrient pollution reduction as a
priority for EPA. Underlying any approach to the
reduction of nutrients (nitrates and phosphorus) in
the environment is the need to measure concentra-
tions in a timely manner.
I LTV Advanced Monitoring
Systems Center
John McKernan, EPA Project Officer
Phone: (513)569-7415
Email: mckernan.john(g),epa.gov
Amy Dindal, Battelle
Phone:(561)422-0113
Email: dindala@battelle.org
Final outfall sampling location for nutrient monitor testing
1 The ETV Program operates largely as a public-private partnership through competitive cooperative agreements with non-profit research institutes. The pro-
gram provides objective quality-assured data on the performance of commercial-ready technologies. Verification does not imply product approval or effective-
ness. ETV does not endorse the purchase or sale of any products and services mentioned in this document.
www.epa.gov/etv
-------
Table 1. Description of Nutrient Monitoring Technologies
Technology Vendor and
Name
Technology Description
Shimadzu Scientific Instru-
ments, Inc.
TNPC-4110(C)On-Line
Water Quality Analyzer
The analyzer can monitor total nitrogen, phosphorus, and organic carbon (TOC) in source and product waters.
TOC monitoring was not verified in this test, although TOC measurements were taken during on-line effluent
monitoring. The analyzer can be used for nutrient monitoring and process control and automatically performs
sampling, pretreatment (physical and chemical), digestion, and analysis. Total phosphorus is measured
through a photochemical oxidation process, with colorimetric quantification. Total nitrogen is measured using a
catalytic combustion method, with chemiluminescent quantification.
ZAPS Technologies, Inc.
Multi-Parameter Analyzer
(MP-1)
The analyzer was designed as a first-alert system for water treatment plants for monitoring of nitrate in source
and product waters. The analyzer uses a sequential fiber-optic spectrometer that measures nitrate by its light
absorption at 220 nanometers. Because it can operate from 200 to 800 nanometers, the analyzer is capable
of providing > 100 channels of optical data by monitoring absorption, fluorescence, and total reflection bands.
The verification test was configured to measure corrected nitrate absorption, temperature, and several other
channels related to dissolved organic carbon, complex hydrocarbons, bacterial abundance, and chlorophyll a.
Only measurements of nitrate were verified.
Selected Outcomes of Verified Nutrient Monitoring Technologies
To address nutrient levels in surface and ground waters and reduce potential human health and environmental con-
cerns, the EPA has established regulations and standards under the Clean Water Act (CWA) and Safe Drinking Water
Act (SDWA) that require nutrients to be at or below recommended or established levels. Under the CWA, the EPA
requires states to establish total maximum daily loads (TMDL) to regulate nutrient loadings in impaired water bodies.
TMDLs have been established for total nitrogen and phosphorus within various segments of the watershed of the
Chesapeake Bay in Virginia, where the verifications were conducted. The SDWA has established maximum contami-
nant levels (MCL) of 10 milligrams per liter as nitrogen (mg/L as N) for nitrate and 1 mg/L as N for nitrite. There is
no established MCL for phosphorus. The
primary health risks of nitrate and nitrite in
drinking water are to infants. Drinking ni-
trite or nitrate containing water can result
in increased incidence of methemoglobine-
mia, a blood disorder that interferes with
the body's processes for carrying oxygen
to cells and tissues (EPA, 2002). Along
with compliance monitoring initiatives,
real-time monitoring technologies, such as
those verified, can be used to provide tem-
poral analysis of when changes in nutrient
loading occur and assist in determining
when enhanced control of wastewater treat-
ment systems is needed. Below are the
benefits of the nutrient monitoring verifica-
tion tests.
• A peer-reviewed test protocol has advanced efforts to standardize protocols.
• The verifications conducted support the use of on-line monitoring technologies for detecting nutrients in
source and treated effluent waters.
• Verification activities support EPA's objective to manage and reduce nutrient loadings by providing effective
tools for wastewater and environmental monitoring.
References
APHA. 1992. Standard Methods for the Examination of Water and Wastewater, 18th Edition, American Public Health
Association, Washington D.C.
U.S. EPA. 2002. Integrated Risk Information System (IRIS) Health Assessment Information for Nitrates and Nitrites.
Updated December.
U.S. EPA, ETV Program, http://www.epa.gov/etv
U.S. EPA, Water Quality Criteria for Nitrogen and Phosphorus Pollution, http://www.epa.gov/waterscience/criteria/
nutrient/basic .htm
www.epa.gov/etv
September 2009
EPA/600/S-09/028
Table 2. Selected Performance of Nutrient Monitoring Technologies
Technology
MP-1
TNPC-4110(C)
TNPC-4110(C)
Test Range, mg/L
TN:0.1-5
TN:0.5-20
TP:0.5-5
LOD, mg/L
TN: 0.232
TN: NDa
TP: 0.141
Average Recovery, %
TN: 157
TN: 131
TR118
3 Not determined, total nitrogen was not detected in samples to determine the LOD
------- |