UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
VERIFICATION STATEMENT
TECHNOLOGY TYPE: ULTRAVIOLET RADIATION USED IN PACKAGED
DRINKING WATER TREATMENT SYSTEMS
APPLICATION: MICROBIOLOGICAL CONTAMINANT INACTIVATION
TECHNOLOGY NAME: SENTINEL™ ULTRAVIOLET REACTOR (R-ll, Model 6-1)
COMPANY: CALGON CARBON CORPORATION
OXIDATION TECHNOLOGIES
ADDRESS: 130 ROYAL CREST COURT
MARKHAM, ONTARIO, CANADA L3ROA1
TELEPHONE: (905) 477-9242
The U.S. Environmental Protection Agency (EPA) has created a program to facilitate the deployment of
innovative technologies through performance verification and information dissemination. The goal of the
Environmental Technology Verification (ETV) Program is to further environmental protection by
substantially accelerating the acceptance and use of improved and more cost effective technologies. The
ETV Program is intended to assist and inform those involved in the design, distribution, permitting, and
purchase of environmental technologies. This verification statement provides a summary of the
performance results for the Calgon Carbon Corporation (CCC) Sentinel™ Ultraviolet Reactor, R-ll,
Model 6-1 (Sentinel™). The Sentinel™1 is a package drinking water treatment system that uses medium-
pressure ultraviolet (UV) lamps operating at a higher temperature than low-pressure lamps to produce a
broad spectrum of UV light with a higher irradiance to inactivate microbiological contaminants.
ABSTRACT
The EPA and NSF International (NSF) verified the performance of the Sentinel™1 under the EPA's ETV
program. The Sentinel™1 obtained an estimated 3.9 logio inactivation of Cryptosporidium parvum (C.
parvuni) as determined by animal infectivity methods, at an estimated UV dose of 20 mW-s/cm2, when
fed finished (treated but not chlorinated) water that was seeded with C. parvum at a flow rate of
approximately 215 gallons per minute (gpm). When using oilier methods (vital dyes and in vitro
excystation), a maximum of 1.2 logio inactivation of C. parvum was observed. During the
microbiological seeding challenge, the finished water fed to the system had these characteristics:
• turbidity less than or equal to 0.11NTU
• nitrate less man or equal to 4.0 milligrams per liter (mg/L)
• pH range of 7.40-7.76
• temperature range of 8.8 - 12.3 °C
• UV 254 absorption coefficient ranges 0.02-0.06 cm"1.
EPA/600/R-98/160VS The accompanying notice is an integral part of this verification statement. May 1999
Iof6
-------
At a flow rate of 25 gpm, the Sentinel™'s power requirements were verified as 1.046 + 0.046 kW per
lamp at full power. Three of the UV irradiance sensors failed and some of the automatic quartz sleeve
wipers had operational difficulties including a broken weld. CCC informed NSF of their intent to
improve these portions of the Sentinel™.
Details of the verification testing, including the testing data and discussion of results, may be found in the
report entitled "Environmental Technology Verification Report: Inactivation of Cryptosporidium parvum
oocysts in Drinking Water: Calgon Carbon Corporation's Sentinel™ Ultraviolet Reactor" (EPA/600/R-
98/160).
PROGRAM OPERATION
The EPA, in partnership with recognized verification organizations, objectively and systematically
evaluates the performance of innovative technologies. Together, with the full participation of the
technology developer, they develop plans, conduct tests, collect and analyze data, and report findings.
The evaluations are conducted according to a rigorous demonstration plan and established protocols.
NSF, a not-for-profit organization dedicated to public health safety and protection of the environment,
assured data quality objectives were met during testing through their oversight and management of
verification activities. The verification testing of the Sentinel™1 was performed by Cartwright, Olsen and
Associates, LLC (COA), an NSF-qualified Field Testing Organization for the Package Drinking Water
Treatment Systems (PDWTS) ETV Pilot.
TECHNOLOGY DESCRIPTION
The Sentinel™ is a medium pressure UV water treatment system designed to inactivate microbiological
contaminants. There are two major UV light technologies: low-pressure and medium pressure lamps. The
low-pressure lamp UV light technology emits most of its energy at the 253.7 nm wavelength. The
medium pressure lamps produce a broad spectrum of UV light (extending over the 200-300 nm range
with a maximum output at about 255 nm) with a higher irradiance and operating at a much higher
operating temperature (surface temperatures >500°C) than low pressure lamps. The linear power density
is also much higher (typically 100-300 W/cm).
The system is a skid-mounted, stand-alone system equipped with a control panel, power supply,
transformer, and fail-safe and monitoring controls. The system has two UV reaction chambers contained
within a stainless steel column (dimensions: 10" diameter, 80" tall). Each reaction chamber has three 1
kW medium pressure ultraviolet lamps. Each lamp can be operated at full or reduced power. Each lamp
is contained within a quartz sleeve aligned perpendicular to and across the flow of the water. The UV
dose for the system is calculated using a multiple point source summation (MPSS) model that is
undergoing a peer review. The hydraulic design for the system is for continuous flow rates up to 500 gpm
(0.7 mgd). Throughout the verification testing period, the system was operated at a flow rate of 25 gpm
during regular flow conditions and at approximately 215 gpm (814 L/min) during inoculated feedwater
conditions.
VERIFICATION TESTING DESCRIPTION
In March and April of 1998, the ability of the Sentinel™1 Ultraviolet Reactor to inactivate the protozoa C.
parvum oocysts was tested at the Mannheim Water Treatment Plant in Kitchener, Ontario, Canada.
The Grand River is the source water for the Mannheim Water Treatment Plant. Pretreated surface water
(treated by coagulation, flocculation, sedimentation, ozonation, and filtration) was inoculated with C.
parvum oocysts and fed to the Sentinel™1. The pretreated surface water exhibited the following
characteristics during the microbiological seeding portion of the verification testing: turbidity
concentrations less than or equal to 0.11 NTU; pH range 7.40-7.76; temperature range 8.8-12.3 °C; nitrate
EPA/600/R-98/160VS The accompanying notice is an integral part of this verification statement. May 1999
Page 2 of 6
-------
concentration less than or equal to 4.0 milligrams per liter (mg/L); total organic carbon (TOC)
concentration less than or equal to 4.5 mg/L; UV254 absorption coefficient range 0.02-0.06 cm"1.
Methods
During each day of the verification test, samples of the feed and finished water were collected, labeled
and analyzed. All analyses were performed in accordance with the procedures in Standard Methods.
The purpose of the microbiological challenge test was to demonstrate the effectiveness of the application
of medium pressure UV lamps as configured in the Sentinel™ equipment in inactivating the protozoan
oocysts in the field. The challenge testing was performed on finished water representing a uniform water
quality matrix.
The Sentinel™ was challenged with live oocysts and consisted of the following steps:
1) the introduction of live oocysts into the water stream and their passage through the Sentinel™,
2) the recovery of the oocysts from the water stream,
3) the determination of their viability and/or infectivity,
4) the calculation of logio inactivation.
The organisms were introduced upstream of a static mixer ahead of the reactor and collected on 1 (jm
filters after the reactor. The overall flow rate during the tests was approximately 215 gpm (814 L/min).
The filters were shipped to Clancy Environmental Consultants, Inc. (CEC) in Vermont where the
organisms were isolated, concentrated and subjected to analysis by in vitro methods to determine
viability. Additionally, for C. parvum oocysts, animal infectivity experiments were also conducted to
ascertain the levels of inactivation demonstrated by in vitro assays and to provide further evidence for the
correlation between in vitro methods and neonatal mouse infectivity, following oocyst exposure to UV
light. The details of the seeding, recovery, and viability assays are found in Clancy et al. (1998).
VERIFICATION OF PERFORMANCE
The following is a summary of the findings of the verification testing of the Sentinel™:
Water Quality Results
The following two tables present the mean, minimum, and maximum water quality parameter
concentration results of the influent and effluent samples collected during the verification testing:
On-Site Water Quality Sampling Results (March 30 through April 13)
Temp. pH2 Bench In-Line
("Q1 Turbidity3 Turbidity4
Mean
Minimum
Maximum
10.4/11.4
8.8/8.8
11.0/12.4
7.6/7.6
7.4/7.4
7.8/7.7
0.095/0.094
0.056/0.053
0.147/0.134
0.072/0.077
0.041/0.041
0.112/0.147
1 - Temperature from influent/effluent of reactor.
2 - pH from influent/effluent of reactor.
3 - Turbidity in NTU from bench influent/effluent of reactor.
4 - Turbidity in NTU from on-line turbidimeter, filter 3/filter 4.
Laboratory Water Quality Sampling Results (microbial challenge test days)
Mean
Minimum
Maximum
Alk
(mg/1)1
164/164
150/150
180/180
Al
(mg/1)1
0.26/0.3
0.06/0.08
0.86/0.48
Color
(TCU)1
5/5
5/5
5/5
Iron
(mg/1)1
0.15/ND
ND/ND
0.5/ND
Mang
(mg/1)1
0.01/.01
ND/ND
0.03/0.02
NO3
(mg/1)1
3.58/3.34
3/3
4/3.7
UV254
(cm'1)1
0.0464/0.0366
0.0365/0.0214
0.0551/0.0427
1 - Concentration from influent/effluent of reactor.
ND = Not Detected
EPA/600/R-98/160VS The accompanying notice is an integral part of this verification statement. May 1999
:3of6
-------
Microbiological Results
Results of the C. parvum inactivation by the Sentinel™ as determined by animal infectivity, vital dyes,
and in vitro excystation studies are presented in the following table:
Summary of the Results of C. parvum inactivation by the Sentinel™
Challenge
Date
3/31/98
4/6/98
4/7/98
4/1/98
4/8/98
Sentinel™
UV Dose at 215 gpm
(mW-s/cm2)
167 (High) - 2 lamps full
152 (High) - 2 lamps full
137 (High) - 2 lamps full
69 (Medium) - 2 lamps
reduced
20 (Low) - 1 lamp reduced
%Trans-
mittance
90.0
89.4
87.9
90.1
91.1
Log10 Inactivation
via animal
infectivity
>4
Not Done
Not Done
>4
3.9
Vital dyes
assay
(D API/PI)
1.2
0.9
0.5
0
0
In vitro
excystation
0.4
0.4
0.2
0
0
Mouse infectivity assays with high and medium UV doses demonstrated no infection in neonatal mice
despite oral inoculation of up to 1x105 oocysts. The oocysts which had been exposed to a low UV dose
resulted in 4.5% infection (1 of 22 mice) with an inoculum of IxlO5 UV exposed oocysts per mouse;
however, no mice were infected when inocula of either IxlO4 or IxlO3 UV exposed oocysts were
administered into a total of 36 mice.
Operations and Maintenance Results
During the verification period, aspects of the operation were evaluated to determine insofar as is possible
over a brief period, the degree of maintenance and "hands on" attention required. For this observation the
equipment was run continuously and monitored 24 hours a day until the completion of a period of 27
days. Results observed included:
• Three of the contained irradiance sensors failed due to unexpected electronics problems. CCC is
taking action to redesign the sensor circuit board.
• The automatic quartz sleeve wipers ceased operating for many reasons including a broken weld.
The wiper mechanism is being redesigned and will be the subject of a separate ETV evaluation.
CCC has determined that the cause of wiper failure was the impact force of the brush with the
wiper stop at the end of the extended travel position.
• During the maintenance period the power consumption was approximately 1.046+0.046 kW per
lamp. Assuming daily operation of six lamps at full power, the power demand is estimated at
150.6 kW per day.
• The O&M manual supplied by the manufacturer was specific to this equipment and included all
the components of the pilot plant. Drawings and illustrations showing the positions of the meters
and controls are included along with explanations of control functions and step-by-step
instructions for common maintenance functions, such as: replacement of lamps, quartz tube
cleaning and reactor cleaning. Complete instructions for equipment start-up and shut-down
procedures were listed in this guide. The control panel is thoroughly explained so that all
programmable functions, including wiper cycles, lamp set-points for alarms and other PLC
parameters are easily learned by even inexperienced personnel. Safety measures included
detailed instructions concerning high voltage, protection against UV irradiance, and the
EPA/600/R-98/160VS
The accompanying notice is an integral part of this verification statement.
Page 4 of 6
May 1999
-------
procedures for mercury spills in the event of lamp breakage. A trouble shooting guide was
furnished.
Conclusions
Through this testing it was established that at a process flow rate of approximately 215 gpm the
Sentinel™ could obtain an estimated 3.9 logio inactivation of C. parvum oocysts as determined by animal
infectivity results with one lamp illuminated (out of six) at reduced power (0.5 kW). Greater (> 4 logic)
inactivation was achieved at 215 gpm with higher UV doses, respectively, with two lamps at reduced
power (0.5 kW each), and with two lamps at full power (1.0 kW each), again as determined by animal
infectivity results.
Furthermore, the use of in vitro methods (vital dyes and in vitro excystation) significantly under-
estimated oocyst inactivation when compared to neonatal mouse infectivity.
During the verification period, water quality parameters that influence UV absorbance were measured to
assist in evaluating other waters for application of this UV system. During the challenge periods, UV254
absorption coefficient was between 0.02 and 0.06; turbidity was <0.11 NTU. No iron or manganese was
detected in the sample water; nitrates were no greater than 3.7 mg/L and total organic carbon was no
greater than 4.3 mg/L.
Also of importance to this study was the operation of the equipment in the field. Several deficiencies
were noted with wiper failures, irradiance sensor, and attenuation tubes. CCC has informed COA and
NSF that they are taking action to improve these portions of the system.
Limitations
The PDWTS ETV Pilot verifies the performance of innovative water treatment systems using consensus
methods and procedures. This verification identified limitations associated with the use of non-standard
methods. For example, the verification identified concerns about the methods for assessing oocyst
viability and estimating UV dose. The lack of consensus on evaluation methods and procedures or the
application of a technology is a reflection of the uncertainties associated with emerging technologies,
developing analytical techniques and engineering applications. The resolution of these uncertainties is
within the purview of rigorous scientific research and not the ETV program. A detailed description of the
methodology limitations associated with this performance testing is provided in the Verification Report
(EPA/600/R-98/160).
Original Signed by
E. Timothy Oppelt
5/17/99
Original Signed by
Tom Bruursema
5/13/99
E. Timothy Oppelt Date
Director
National Risk Management Laboratory
Office of Research and Development
United States Environmental Protection Agency
Tom Bruursema Date
General Manager
Environmental and Research Services
NSF International
NOTICE: Verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. Mention of corporate
names, trade names, or commercial products does not constitute endorsement or recommendation
for use of specific products. This report is not a NSF Certification of the specific product
mentioned herein.
EPA/600/R-98/160VS
The accompanying notice is an integral part of this verification statement.
Page 5 of 6
May 1999
-------
Availability of Supporting Documents
Copies of the ETV Protocol for Equipment Verification Testing for Inactivation of
Microbiological Contaminants dated March 8, 1998, the Verification Statement
(EPA/600/R-98/160VS), and the Verification Report (EPA/600/R-98/160) are available
from the following sources:
(NOTE: Appendices are not included in the Verification Report. Appendices are
available from NSF upon request.)
1. Drinking Water Systems ETV Pilot Manager (order hard copy)
NSF International
P.O. Box 130140
Ann Arbor, Michigan 48113-0140
2. NSF web site: http://www.nsf/etv (electronic copy)
3. EPA web site http ://www.epa. gov/etv (electronic copy)
EPA/600/R-98/160VS The accompanying notice is an integral part of this verification statement. May 1999
:6of6
------- |