By Beth Thomas

Thorough risk management assessments need to be included for commercial, industrial and community systems. This is especially true when treating contaminants that have serious health effects like arsenic that may have coverage exclusion clauses in the liability policy.

A 10-gpm arsenic removal system in series configuration in New Hamsphire

A successful US EPA project: 100-gram arsenic removal system in series configuration in Arizona.

More and more communities and individuals are in the process of selecting arsenic treatment systems to meet US EPA standards. A critical and often frustrating step is answering the question, “How much will a system cost and what will the on-going maintenance and operating expenses be?”

As owners of many arsenic treatment systems are discovering, initial system capital cost is only one part of the total cost equation. Most items of analysis will apply to systems of any size, from POU systems to those for community water companies.

The approach is not much different than the questions one would ask for any other type of water treatment system. The initial price of the system, including the design, pilot testing (if required), permitting costs, equipment, site preparation, installation and start-up and commissioning costs are usually known from bids or sales proposals.

These costs will vary depending on the size of the unit, the treatment technology chosen and the degree of complexity based on the features that are added. Other costs at the time of purchase include the cost of financing the purchase and liability insurance for community systems, whether private or public.

A 50-gpm arsenic, iron and manganese removal system in parallel configuration in Maryland

Risk and maintenance
Thorough risk management assessments need to be included for commercial, industrial and community systems. This is especially true when treating contaminants that have serious health effects like arsenic that may have coverage exclusion clauses in the liability policy.

Once the system is in operation, maintenance expenses occur. These expenses are not covered in the system warranty. Frequency depends on the amount of water used and the quality of water being treated. Failure to perform these services may result in poor water quality or system failure.

The price and schedule for these services and components might have been discussed in the original sales proposal or listed in the operations and maintenance manual. If not, the water treatment company from whom the system was purchased can provide the information.

For residential units, this will mean filter cartridge, membrane or media replacements and control valve service. Larger systems may have chemical feed costs, media replacements and equipment maintenance schedules to be considered.

Periodic water analyses should be performed to verify that the system is performing as required and that the arsenic is being removed. This may be done by an in-house maintenance person or contracted to a water treatment professional. These maintenance and laboratory costs should be considered and budgeted when totaling the true cost of a system.

For community systems, a state-licensed operator is required to maintain the system and perform routine system field tests and laboratory sampling. These operations must be logged and reported to the appropriate state agency. The level of operator license and sampling frequency depends on complexity of the system and number of people served.

Maintenance tools, testing equipment and laboratory tests, consumables like chlorine, pH adjustment chemicals, coagulation additives, filters, media replacement expenses and the operator’s salary are part of the on-going expenses of the system.

These expenses need to be calculated and budgeted as part of the selection decision for any system. Failure to do so can have serious consequences for the community’s budget and the people being served.

A 450-gpm arsenic and iron removal system in parallel configuration in Michigan.

Demonstration process
The US EPA has done two rounds of demonstration projects throughout the country to prove the efficacy of various arsenic treatment media and techniques. These demonstrations succeeded in their goal of identifying emerging treatment technologies and vendors who have been successful.

An arsenic treatment technology decision tree was created and posted on the agency’s website as a selection tool. However, it does not adequately address all of the concerns covered here. Treatment selection will impact both capital and operating costs of the system.

Part of the US EPA’s analysis on these projects is the cost of on-going operations. Two systems in Arizona demonstrate the need to consider these costs. One system began the test using an iron-impregnated activated alumina-based (AA) media as the media of choice.

While AA is low cost and does remove arsenic (V), the throughput capacity is not nearly as high as other media. Therefore, multiple change-outs of the product were needed over time and the operating expense became too costly to be a feasible option for the community. The AA media was subsequently replaced with another higher capacity iron-based media that had more than five times the capacity.

Activated alumina-based media, while suitable for a few applications, has only 10-15 percent of the capacity to exhaustion (in bed volumes) than higher performing granular ferric oxide media. It also requires a longer empty-bed contact time to perform, which means larger vessel design, more media to accomplish the same result and higher capital costs and footprint.

For each site visit to replace media, the labor, material and disposal costs can easily equal the cost of the media itself. To make the process more economically feasible, AA can be regenerated onsite. However, this requires caustic and acid which are expensive, add complexity, create potential safety concerns and require a higher level operator.

In contrast, the second site nearby (also north of Phoenix, Arizona) with higher arsenic concentrations averaging near 60 ppb, employed a high-capacity granular ferric oxide media that exhibited both higher removal efficiency (consistently treating to below the MCL) and total adsorption capacity, which resulted in significantly lower life cycle costs when considering all factors such as frequency of media replacement, media costs, transportation and disposal.  Media pricing per cubic foot for the iron media was higher, but the greatly longer run length resulted in significantly lower total O & M cost. This system has been in operation since June 2004 with only a single media replacement.

SCWS problems
According to Dustin Hardwick of the California Rural Water Association, some small community water systems have been forced into receivership or closed down and taken offline due to operational failures that put the health of the population in jeopardy. In some cases, this has been due to operating costs that exceeded the budget or special funding.

Owners may be unwilling or unable to raise the water rates to cover the total expenses of the system, or simply unaware of all of the costs. A small community in California’s Central Valley is currently out of compliance because proper maintenance and media replacement has not occurred as scheduled, placing the residents’ health at risk.

Driven by affordability issues, the community is facing consequences of their MCL violation, including potential fines from California DPH that can be as high as $3,000 (USD) per day, when systems are out of compliance. In places like California, it has also resulted in systems being forcibly merged with nearby communities, which means the original owners’ investment was lost and the homeowner has to pay higher water rates.

A small community US EPA demonstration site in Texas successfully operating since 2006 is now non-compliant in 2009 because the media needs to be replaced and there is no money escrowed in the community’s budget to accomplish it. Money was not, unfortunately, set aside for this expense over the months since the system was put into service and loans or other financing are not available for a consumable item like media.

Based on the expected lifetime of the media, the average monthly operating cost per homeowner for media replacement and maintenance was less than $20 per household.  At the time of the start-up, this extra cost was deemed by their Board to be too much to pass on the system’s one hundred customers.

A similar community in northern Illinois was able to avoid this situation by amortizing the media replacement costs over the life expectancy of that media. This amount has been added to monthly billing rates since the system was brought on-line. The extra money collected was set-aside in a special account for when media has to be replaced.

Based on the 190 connections in the Subdivision, an assessment of approximately $7/month per connection was figured to cover this ongoing incremental expense. When properly planned, this cost was deemed reasonable and affordable for the average homeowner in the community.

Selection process
There are other issues to consider during the selection process that are not directly related to costs but will affect those costs in the long run. The number of media providers for arsenic treatment has decreased as some have gone out of business or the media have not proved effective over time.

As an example, certain ion exchange resins impregnated with iron are no longer viewed acceptable by regulatory agencies in some areas due to concerns about poor performance, odors, arsenic leakage, changes in water chemistry or sudden release of contaminants from the media. Others have simply proven to be too expensive to operate, mostly due to lower capacity than predicted.

This may mean higher media replacement costs and equipment modifications. In some cases, the availability of grants or other ’free’ money led owners to make quick decisions without adequate due diligence on optional treatments.

Many community water systems have applied for stimulus funds for new systems or for additional equipment to meet the arsenic requirements. They have learned that much of this money is in the form of low-interest loans or a combination of loans and grants. That means the cost of the loan should be considered in the total cost analysis.

It is also true that it is not as easy for small systems to obtain this money as it is for the larger municipal systems, so other sources should also be considered. Part of the evaluation of funding must be a consideration of what happens when that money runs out and operational costs continue.

Experience and stability
An evaluation of the experience and stability of the treatment system provider is a way to know the proposed system is the best available technology for the conditions at hand and that the supplier will be there when media replacement is due. Treatment system suppliers need to be very conscience of all costs and maintenance schedules and clearly communicate them in their proposals for client’s consideration.

Water treatment vendors for community water systems should be aware of the costs in relation to client’s situation to know when the costs will require a large rate increase to cover them. Suppliers may offer alternate technologies or provide assistance in finding funding sources.

Selecting a company with this experience is paramount to navigating through this process. Selection of an engineer is also critically important when dealing with regulatory agencies for permits, doing pilot testing and reports when required, managing site and building preparation and construction and evaluating treatment system proposals for the water system owner.

The lessons to be learned about the financial aspects when choosing arsenic treatment water systems are critical to the long-term success of any system. It is important to compare the operating costs as well as capital costs of each technology.

According to the US EPA website, over 4,100 community and non-community systems (schools, churches, factories) serving up to 13 million people have arsenic levels above the maximum contaminant level of 10 parts per billion arsenic. The budget planning process for small water systems having less than 500 connections (which represents the majority of communities dealing with this issue in the US) must include preventive maintenance expenses and media replacement costs and have money set aside for scheduled and unexpected events. Homeowners that are served by these systems need to be aware of these issues so that they (or their engineer, board, or representatives) can select the appropriate technology, make good business decisions, engage with the system suppliers, and understand total life cycle costs of any new systems that are considered for their community.  These considerations will improve the long-term success of systems, the owners, the residents, and the suppliers.

Important Questions to Ask a Vendor When Choosing an Arsenic System

Feasibility

• What are the water quality limitations of this media/treatment technology?
• Is my water quality a good match with the capabilities of this treatment option?
• What kind of pre-treatment is needed?
• Can the technology reliably achieve less than 10 ppb?
• Is the technology likely to be permitted (or has it been)?

Experience

• Is the product commercially and readily available?
• How many installations or similar systems does this company have operating?
• Does the media or process meet certifications or standards such as NSF/ANSI?
• Are there other installations or case studies with similar water profile available for references?
• Is the technology proven and can a performance guarantee be provided?

Space, residuals, other

• What are the space requirements to house this equipment?
• How flexible is the system? Easy to update or add-on?
• What type of waste streams and quantities are associated with this treatment? Hazardous waste?

Costs

• What are the capital costs of this treatment?
• What are the typical O&M costs based on the specific water profile? ($/1000 gallons for comparisons)
• How much operator time will be required to operate and maintain the system?
• What warranties do you offer?

About the Author
Beth Thomas is a Project Manager at AdEdge Technologies in Buford, GA, a company specializing in design, development, manufacturing and supply of technologies that remove contaminants from process or aqueous streams, including adsorbent-based products, coagulation/filtration, oxidation/filtration, ion exchange and membrane filtration. She earned a Bachelor’s Degree in science from Metropolitan State University in Denver, CO where she majored in biology and chemistry.