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Overview of UV Validation Facility Owned by Carollo, on Portland Water Bureau's Groundwater Pump Station Site

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September 16, 2011 (PDF version)


Overview of UV Validation Facility Owned by Carollo, on Portland Water Bureau’s Groundwater Pump Station Site



In response to questions about the agreement the Portland Water Bureau has with Carollo Engineers, Inc. to lease portions of the Water Bureau’s groundwater production facility to run a UV validation facility, as well as the rates Carollo pays for the water they use, we have prepared this overview.

The rate that Carollo pays for each unit of water is based on a “cost-of-service” model and is for raw water consumption that does not utilize the Water Bureau’s distribution system. It is not by any stretch of the imagination the same potable water any of our customers receive via the Water Bureau’s extensive distribution system. In addition, the agreement generates significant revenue for the Water Bureau.

It should be clear that the Water Bureau’s relationship with Carollo as a large water use customer predates the decision by the Portland City Council to comply with LT2 by building a UV facility in lieu of filtration by almost a decade. The threat to the watershed from the recent Dollar Lake fire drives home the rationale that the Water Bureau and Commissioner Leonard articulated when advocating for a direct filtration method for meeting the treatment component of LT2 when the Council was weighing compliance options in 2009. Even though filtration is a more expensive compliance option than UV, the bureau and Commissioner Leonard identified filtration as the preferred option because it provides greater benefits, including the continued use of Bull Run water during turbidity events, compliance with future treatment requirements that may arise, and insurance against the threat of fire or other natural catastrophe in the Bull Run. However, the City Council voted to pursue UV as the least cost alternative to comply with the rule. Carollo’s participation as a partner with one of the design firms on the UV plant that we will build if we do not get a variance is a direct result of the Council’s decision to select UV as our compliance option over the more expensive filtration option.


The U. S. Environmental Protection Agency requires performance validation of potable water treatment systems using UV light for cryptosporidium inactivation.

In 2002, the consulting engineering firm Carollo Engineers, Inc. approached the Portland Water Bureau about using groundwater to validate UV reactors. Carollo wanted our water supply and site because our groundwater is very pure - there are no contaminants and the clarity is very high, which allows them to run a wide range of tests. We can also provide up to 70 million gallons per day (mgd) and we have a location to discharge that much water. The Water Bureau recognized that this was a way to sell untreated water at times when the groundwater wells and storage tank were otherwise unused. Lease agreements were negotiated covering use of the site and the cost of the water and approved by the Portland City Council in December 2002. Carollo then built temporary facilities on the west side of the bureau’s Groundwater Pump Station site and started using them in 2003.

Revenue from Carollo

Carollo is currently charged $0.46 per hundred cubic feet of raw groundwater, a base rate of $0.826 per day, and is charged for staff time, including all overhead, needed to coordinate activities and calculate the amount of water provided on Carollo’s behalf.

Only the well pumping facilities, the groundwater collection mains, the storage tank, and discharge facilities are used to supply water to Carollo, and are only used when the bureau is not using the facilities for potable water use. The agreement specifies that Carollo’s use is interruptible and subordinate to potable (treated) water use. The water provided to Carollo is not treated, and no transmission or distribution facilities were built to convey water to Carollo’s facility. In contrast, all retail and wholesale customers receive treated water, and most are served by distribution or transmission pipes, and dedicated flowmeters.

Carollo pays for their proportionate share of the facilities they use and their proportionate share of the operating costs of those facilities, just like our wholesale customers. Carollo pays the full cost of service for the water they receive. The rates are recalculated every year, included in the rate book, and are approved by City Council. This is consistent with the practice since the 1980s to charge cost-of-service rates. This is true regardless of the circumstances or frequency of a situation occurring. The same rates apply to any customer seeking to receive untreated water exclusively from the Columbia South Shore Well Field.

How Water is Supplied

To supply water to Carollo, well pumps are remotely turned on to fill the Groundwater Storage Tank. Water flows by gravity from the tank to Carollo’s test reactors, then through downstream facilities to the Columbia Slough. The tank is normally kept full and overflowing to maintain a constant head and a constant flow. We measure the flow into the tank with bureau meters and the Supervisory Control and Data Acquisition (SCADA) system.

Benefits to the Water Bureau

There are several benefits to the Water Bureau from the agreement with Carollo. We can sell water at times when the well facilities are not needed for potable water. We have attracted a large water user to the City - a customer like this helps us to keep water rates down by off-setting decreasing demands generally. We are cooperating with a local business which is running the largest UV validation facility in the world. Carollo’s facility is part of a newer technology industry that is allowing utilities like ours to meet regulations without going to costlier filtration.

By operating production well pumps, motors, and valves several times a year, we can ensure their readiness and make repairs before the facilities are needed for potable water, rather than during peak use season or during emergency water supply conditions.

We have been able to see a variety of UV reactors in use at our site, which is helping us design the EPA-required UV treatment system for the Bull Run supply if our variance request is denied. The UV reactor model that we plan to use in Bull Run if the variance request is denied will be tested here in Portland.


The funding for the UV validation facility has all been private. It is a partnership of Carollo and four UV manufacturers, Wedeco, Calgon, Trojan and Aquionics. The UV manufacturers pay Carollo for the validation tests that are completed.

NPDES Permit

The Water Bureau has an NPDES discharge permit for discharges from the Groundwater Pump Station to the Columbia Slough, as well as other locations throughout the water system. In 2002 the Water Bureau consulted with Oregon Department of Environmental Quality to include discharges from a UV validation facility to the existing Water Bureau permit. At that time ODEQ concluded that no modification of the existing permit was necessary. Discharges at the UV test facility are discharged through bureau facilities downstream of their test reactors, at one of the outfalls covered by the NPDES permit. The Carollo discharges are sampled and analyzed daily when they operate. To date all discharges have met the water quality parameters established under the bureau’s permit.

There have been two accidental releases of mercury from UV lamps during the history of the facility. In 2003, a lamp broke when water was flowing through the reactor, but the lamp was off. As much as two grams of mercury leaked out as small droplets. An extensive recovery, cleanup, and disclosure effort ensued. It is estimated that most of the mercury was recovered, however some, less than a gram, may have been released to below-ground downstream facilities and the Slough. Bureau staff consulted with the Oregon Dept. of Environmental Quality (ODEQ) and several conclusions were reached: the release was small compared to estimated daily background releases to the Slough from all sources, the release was well below the reportable limit of one pound (454 grams), and ODEQ wouldn’t require a cleanup of the Slough because it would resuspend other long-buried pollutants.

In 2007, two UV lamps of a different type broke, likely because of a PVC diffuser pipe that became detached from inside a Water Bureau pipe and went downstream. The lamps were off at the time. About 1.2 grams of mercury, total, were in the two lamps, in the form of very small droplets dispersed along the length of the lamps. Much of the broken glass and debris was recovered, but it was difficult to quantify how much mercury was recovered. It was assumed that much of the mercury was dispersed through the discharge facilities or the Slough.

The experience of Water Bureau staff during these two incidents helped shape the safety features that are being designed into the Bull Run Supply Treatment facilities.




To validate potable water UV reactors, a surrogate for cryptosporidium (a protozoan pathogen) is typically used. The surrogate (also called “challenge organism”) is often MS2 coliphage, and Carollo typically injects this upstream of the reactors being tested. MS2 coliphage is a type of bacteriophage (a virus that infects and destroys bacterial cells). One of the reasons it is used is because it is harmless to receiving streams. Bacteriophage occurs naturally in Columbia Slough. The Oregon Department of Environmental Quality (ODEQ) has been kept informed of the amounts of discharges from the facilities and the specific surrogates that Carollo adds, and has approved of the discharges.

Carollo also sometimes adds a UV-absorbent to mimic the varying amounts of natural material that contributes to color, and UV absorption, in raw water. The absorbent Carollo initially used was derived from coffee. Carollo now uses lignin sulphonate, a product derived from the lignin found in trees, or Superhume, derived from humic material in plants (and is “reviewed and approved for use in Organic Crop Improvement Association certified organic production systems”). Both materials are harmless to receiving waters.

Effect on the Aquifers

Flows to Carollo have increased the amounts of water withdrawn from the three Columbia South Shore Wellfield aquifers. However, even a relatively high flow year to Carollo – about 300 million gallons – is very small compared to the ultimate capacity of the well field for a year, which is in the range of 20 billion gallons per year.

Water Bureau monitoring and ODEQ-driven cleanups have ensured that contamination is not migrating from cleanup sites in the vicinity of production wells. No VOCs (Volatile Organic Compounds) have been detected in production well water for several years.

Carollo Involvement in Bull Run Supply Treatment Design


hydraulics and have been involved with the UV equipment selection and design of the UV building. They are teamed with Black and Veatch on the treatment process work. Carollo wrote the UV Disinfection Guidance Manual for the EPA. They were hired for this project because of their expertise in UV disinfection. Wedeco, our selected manufacturer, is currently testing the reactor that will be used in our facility (if we build it) at the Portland Validation facility at the Groundwater Pump Station.

National Facility

The Carollo facility is one of three or four facilities in the world that can validate large scale reactors – others are in Germany and New York. The Portland and New York facilities test UV equipment to ensure that it meets the requirement of the USEPA UV Disinfection Guidance Manual.

“Cost of Service” General Discussion

Water Rates are generally based on “cost of service” - users pay in rates for the net costs they impose on the utility, after deducting for the various non-rate sources of revenue. The Portland Water Bureau rates are set on cost of service principals and are designed to provide sufficient revenue to maintain the Water System.

Retail Customers

Retail and wholesale customers share costs for supply, treatment, transmission and pumping, and in addition retail customers pay to have water served directly to their home or business through the distribution system. These distribution costs are not shared with wholesale customers because all the wholesale customers have their own distributions systems. The retail distribution costs cover operating and capital costs associated with mains, storage tanks, pumps, hydrants, and services. 1

Retail revenue requirements must cover all costs for:

• Operation and Maintenance (O&M) costs based on budget plans.

• Capital costs not paid by bond sales.

• Debt Service payments

• Less other revenue (including wholesale revenue)

Wholesale Customers

Wholesale rates are calculated based on the utility basis of cost of service as described in the AWWA Manual of Water supply Practices – M1 – Principles of Water Rates, Fees and Charges. The wholesale rate model was developed to make sure wholesale customers are paying for their share of water costs based on the “cost of service” language set out in the wholesale contracts.

Wholesale customers pay a proportionate share of costs for supply (both Bull Run and groundwater), treatment, and transmission, as well as a small amount of customer service. Each customer pays for the types of facilities they use. Wholesale users on the east side, for example, do not pay for west side transmission. Most of the wholesale customers are served by gravity – but some west side wholesale customers pay the extra costs to have water pumped to their service area. As a result, each wholesale customer has its own unique rate based on the specific facilities it uses and costs that it imposes on the system.

Wholesale rate components include:

• Operation and Maintenance (O&M) costs based on budget plans.

• Return on Investment on assets serving them

• Depreciation on these same assets.

Columbia South Shore Well Field Rate (Carollo)

This is a specialized rate which covers capital and operating costs for supplying untreated well field water. The rate does NOT include the capital or operating costs associated with Bull Run supply, transmission, distribution, storage, etc. It only includes costs related to the well field.

1 A “service” is the line from the main in the street to a user’s meter.

How to enjoy a fountain, as demonstrated by the Portland Opera

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The Ira Keller’s Forecourt fountain will be drained today, Thursday September 22, and will be refilled and operational by the end of the day on Monday, September 26.

And no, it is not being drained because vandals had a post-concert public bubble bath on Tuesday night.

The fountain will be used by the Portland Opera to launch its 47th season and share the beauty and breadth of opera with Portland’s citizens. At Saturday’s Big Night street fair, the fountain will be used to stage a projector that will simulcast the performance taking place inside the Keller Auditorium onto a 40-foot screen, where the public is invited to view the concert in a park setting, FREE of charge. After the performance, the Marx Brother’s movie A Night at the Opera will be aired.

 Keller Foutain in downtown Portland.

The Portland Water Bureau is happy to work with civic and art groups who wish to use this graceful public space to enrich the lives of Portlanders.

These groups go through a fair and equitable process of acquiring permissions and permits and pay for the costs associated with the use of this public resource.

When vandals pour soap in the fountain or otherwise render it inoperable, Portland Water Bureau customers end up footing the bill for repairs, chemicals to treat the water pollution, and, if the water is polluted enough, the cost of draining the fountain of almost 60,000 gallons of water (and replacing it).

So next time someone wants to use the fountain for a public event, just call the Portland Water Bureau at (503) 823-7404 and ASK FIRST.

Otherwise, please leave the fountain alone and allow this public space to be used by all of the public, not just the few who want a bath.

Water Conservation Program has another busy year at neighborhood summer events

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The Water Conservation Program has another busy year at neighborhood summer events!

Table display at community event

Every year the Water Bureau partners with several other City Bureaus to provide information regarding the different sustainability programs throughout the city.  This united effort called "Your Sustainable City", offers a wide variety of information on transportation alternatives, water conservation, recycling, green building, parks services, and stormwater management. We hand out Water Bureau information and conservation devices to the public as well as materials for other sustainable City programs. These fun events present a great way to connect with the community as well as share water knowledge with the public!


Events we were at this summer include: St. John’s Bizarre, Sunday Parkways, Good in the Hood, Multnomah Days, and multiple housing fairs.