Securing Wastewater Facilities: Costs of Vulnerability Assessments, Risk Management Plans, and Alternative Disinfection Methods Vary Widely
Published: 2007-03-30T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: In 2006, GAO reported that many large wastewater facilities have responded to this risk by voluntarily conducting vulnerability assessments and converting from chlorine gas to other disinfection methods. The Clean Air Act requires all wastewater facilities that use threshold quantities of chlorine gas to prepare and implement risk management plans to prevent accidental releases and reduce the severity of any releases. In this study, GAO was asked to provide information on (1) the range of costs large wastewater treatment facilities incurred in preparing vulnerability assessments and risk management plans, and (2) the costs large wastewater treatment facilities incurred in converting from chlorine gas to alternative disinfection processes. To answer these questions, GAO conducted structured telephone interviews with a number of facilities surveyed for the 2006 report. The Environmental Protection Agency (EPA) agreed with the report and provided several technical changes and clarifications.
section_title: What GAO Found
paragraphs: Among the large wastewater facilities GAO examined, the costs reported to prepare vulnerability assessments ranged from $1,000 to $175,000, while costs to prepare risk management plans ranged from less than $1,000 to over $31,000. Whether the documents were prepared in-house or contracted to third parties such as engineering firms was a factor in cost differences. Despite higher costs, some facilities preferred to use contractors due to their expertise and independence. According to one wastewater security official, these attributes can give contractor findings and recommendations greater credibility with utility governing boards that determine spending priorities. One facility that used a contractor to complete a vulnerability assessment in 2002 did so because, at the time, vulnerability assessment software and training were not widely available. Since that time, EPA has increased funding for the development and dissemination of risk assessment software and related training. Overall, cost estimates for vulnerability assessments and risk management plans did not relate to facility size, as measured by millions of gallons of wastewater treated per day. For the large wastewater facilities GAO examined, reports of actual and projected capital costs to convert from chlorine gas to alternative disinfection methods range from about $650,000 to just over $13 million. Most facilities converted, or planned to convert, to delivered sodium hypochlorite (essentially a concentrated form of household bleach shipped in bulk to the facility). Managers of these facilities told GAO they considered other options, but chose delivered sodium hypochlorite because its capital conversion costs were lower than those associated with other alternatives, such as generating sodium hypochlorite on-site or using ultraviolet light. Overall, the primary factors associated with facilities' conversion costs included the type of alternative disinfection method chosen and the size of the facility. Other cost factors facility managers cited included (1) whether existing buildings and related infrastructure could be used in the conversion, (2) labor and building supply costs, which varied considerably among locations, (3) the cost of sodium hypochlorite relative to chlorine gas, and (4) the extent to which training, labor, and regulatory compliance costs were reduced for utilities that no longer had to rely on chlorine gas.

section_title: Letter
paragraphs: Wastewater facilities in the United States provide essential services to  residential, commercial, and industrial users by collecting and treating  wastewater and discharging treated effluent into receiving waters. The  Centers for Disease Control and Prevention cited sewage disposal and  water treatment as important contributors to the control of infectious  diseases, which it considers 1 of the 10 greatest achievements in public  health of the 20th century. Wastewater disinfection, a key component of  the wastewater treatment process, reduces the risk that disease will be  transmitted through wastewater effluents. Historically, chlorination has  been the most commonly used method of wastewater disinfection because  it destroys a variety of pathogens and microorganisms.
Since the events of September 11, 2001, the security of the nation’s water  infrastructure against terrorist threats has received greater attention,  including the potential for terrorist attacks at wastewater facilities that  store large amounts of chlorine gas. If released, chlorine gas may threaten  utility employees and the public near the affected facilities. The gas can be  deadly if inhaled and, at lower doses, can burn the eyes and skin and  inflame the lungs. In a 2004 report, the White House Homeland Security  Council determined that a terrorist attack on an urban chemical facility  that resulted in the rupture of a chlorine gas rail car could kill up to 17,500  individuals and hospitalize as many as 100,000.
While federal law does not require wastewater systems to take security  measures to protect specifically against a terrorist attack, it does require  certain wastewater facilities to take security precautions that could  mitigate the consequences of such an attack. For example, the Clean Air  Act requires wastewater facilities that use threshold quantities of certain  hazardous substances, such as chlorine gas, to prepare and implement a  risk management plan designed to prevent accidental releases of regulated  substances and reduce the severity of those releases that do occur.
As we reported in March 2006, many of the nation’s large wastewater  facilities have improved security since September 11, 2001. For instance, a  substantial number of facilities reported improving security fences,  increasing security lighting, and implementing improved employee and  visitor identification systems, among other security enhancements. In  addition, though not required, many large wastewater facilities reported  that they conducted vulnerability assessments to identify risks to key  process components such as the use, storage, and handling of chlorine  gas. Finally, many facilities reported that they recently stopped or plan to  stop using chlorine gas in favor of alternate disinfection methods.  Commonly used alternatives include sodium hypochlorite, essentially a  concentrated form of household bleach, and ultraviolet light, which breaks  down disease-causing microorganisms.
For wastewater facility managers, the costs of preparing vulnerability  assessments and risk management plans and converting to alternate  disinfection methods must compete for available resources with other  infrastructure needs. For instance, in 2003, in its most recent Clean Water  Needs Survey, the Environmental Protection Agency (EPA) estimated that,  nationwide, wastewater systems faced $181.2 billion in costs to upgrade  treatment systems and sewer lines, reduce the incidences of combined  sewer overflows, which result in the discharge of untreated wastewater  into receiving waters, and meet other pollution control requirements.  Major U.S. cities, including Washington, D.C., and Cincinnati, Ohio, are  facing costs between $1 billion and $2 billion to implement necessary  capital improvements.
This report provides information on (1) the range of costs large  wastewater treatment facilities incurred in preparing vulnerability  assessments and risk management plans, and (2) the costs large  wastewater treatment facilities incurred in converting from chlorine gas to  alternative disinfection processes.
To identify the costs of preparing vulnerability assessments and risk  management plans, we conducted structured telephone interviews with a  select sample of large wastewater facilities identified as having completed  these assessments in our March 2006 report. Our March report identified  106 large facilities that prepared vulnerability assessments or had one  underway and 85 facilities that were required to prepare risk management  plans because they currently used chlorine gas as a disinfectant. From this  universe, we chose a nonprobability sample of facilities based largely on  geographic representation and size.
To identify the costs incurred by wastewater treatment facilities in  converting from gaseous chlorine to alternative disinfection processes, we  conducted structured telephone interviews with most of the 38 large  facilities identified in the March report as having converted recently from  chlorine gas or indicating that they planned to do so. We also conducted  site visits with some of the facilities. Where available, we gathered  documentation, such as capital plans, from these facilities in order to  document conversion costs. We supplemented the cost information we  gathered at individual wastewater facilities with information obtained at  EPA, the Department of Homeland Security (DHS), and nongovernmental  organizations. Reported costs for preparing vulnerability assessments, risk  management plans, and conversion from gaseous chlorine include both  actual and estimated costs. For estimated costs, we asked facility  managers to explain how they arrived at these estimates. Reported costs  were not adjusted for inflation. We determined that reported cost data  were sufficiently reliable to provide useful information about the costs for  preparing vulnerability assessments, risk management plans, and  conversion from gaseous chlorine and the factors that affect these costs.  We conducted our work between August 2006 and March 2007 in  accordance with generally accepted government auditing standards. A  more detailed discussion of our scope and methodology is included in  appendix I.
subsections: section_title: Background
paragraphs: A majority of the nation’s wastewater is treated by publicly owned  treatment works that serve a variety of customers, including private  homes, businesses, hospitals, and industry. These publicly owned  treatment works are regulated by the Clean Water Act. Wastewater  treatment includes a collection system (the underground network of  sewers) and a treatment facility. Wastewater enters the treatment facility  through the collection system, where it undergoes an initial stage called  primary treatment, during which screens remove coarse solids, and grit  chambers and sedimentation tanks allow solids to gradually sink. Next,  wastewater enters secondary treatment, where bacteria consume most of  the organic matter in the wastewater. After these processes, wastewater is  disinfected to eliminate remaining pathogens and other harmful  microorganisms.
Wastewater facilities typically use both chemical and physical disinfection  methods, including the following:    Chlorine gas. Injecting chlorine gas into a waste stream has been the  traditional method of disinfecting wastewater. Chlorine gas is a  powerful oxidizing agent, is relatively inexpensive, and can be stored  for an extended period of time as a liquefied gas under high pressure.  Also, the residual chlorine that remains in the wastewater effluent can  prolong disinfection after initial treatment. However, chlorine gas is  extremely volatile and hazardous, and it requires specific precautions  for its safe transport, storage, and use. Because it is stored and  transported as a liquefied gas under pressure, if accidentally released,  chlorine gas can quickly turn into a potentially lethal gas. EPA requires,  among other things, that any facility storing at least 2,500 pounds of  chlorine gas prepare a risk management plan that lays out accident  prevention and emergency response activities. At certain  concentrations, the residual chlorine that remains in wastewater  effluent is toxic to aquatic life, so wastewater facilities that use  chlorine compounds may also need to dechlorinate the treatment  stream before discharging it to receiving waters. Chlorine can also  oxidize certain types of organic matter in wastewater, creating  hazardous chemical byproducts, such as trihalomethanes. Our March  2006 report found that many large wastewater facilities have  discontinued, or are planning to discontinue using chlorine gas as a  disinfectant in favor of alternative disinfection methods such as sodium  hypochlorite delivered in bulk to the facility. Of the 206 large  wastewater facilities responding to our survey, only 85 facilities  indicated they currently use chlorine gas, and 20 of these facilities plan  to switch from the gas to another disinfectant.
Sodium hypochlorite. Injecting sodium hypochlorite—essentially a  concentrated form of household bleach—into a waste stream is  another chlorination method of disinfecting wastewater. Sodium  hypochlorite is safer than chlorine gas because, if spilled, it remains  liquid and can be contained and recovered. For this reason, it is not  subject to EPA’s risk management planning requirements. However,  sodium hypochlorite is more expensive than chlorine gas, and it  degrades quickly if it is exposed to sunlight or is not kept at proper  temperatures. For this reason, properly storing delivered sodium  hypochlorite in the concentration necessary to disinfect wastewater  may require an on-site building with environmental controls. Sodium  hypochlorite can also be generated on-site at a wastewater facility  using an “electrochlorination system” that produces sodium  hypochlorite through an electrical reaction with high-purity salt and  softened water. Facilities choosing this method of disinfection reduce  chemical costs, but face increased electrical costs from the generation  equipment. Because it is a chlorine compound, wastewater facilities  using sodium hypochlorite must also be concerned with residual  chlorine and hazardous chemical byproducts, such as trihalomethanes.
Ultraviolet light. This disinfection method uses ultraviolet lamps to  break down disease-causing microorganisms in wastewater.  Wastewater passes through an open channel with lamps submerged  below the water level. The lamps transfer electromagnetic energy to an  organism’s genetic material destroying the ability of its cells to  reproduce. Because ultraviolet light is a physical process rather than a  chemical disinfectant, it eliminates the need to generate, handle,  transport, or store hazardous and corrosive chemicals. In addition,  there are no harmful residual effects to humans or aquatic life.  However, ultraviolet light disinfection may not be effective given the  turbidity of some wastewater streams. Wastewater facilities using  ultraviolet instead of chlorine gas or delivered sodium hypochlorite for  disinfection will face additional costs to maintain lamps and increased  electrical costs.
Ozone. This disinfection method feeds ozone generated on-site from  oxygen exposed to a high-voltage current into a contact chamber  containing wastewater. According to EPA, ozone is very effective at  destroying viruses and bacteria, but it is the least used disinfection  method in the United States largely because of its high capital and  maintenance costs compared to available alternatives.
According to EPA, vulnerability assessments help water systems evaluate  susceptibility to potential threats such as vandalism or terrorism and  identify corrective actions that can reduce or mitigate the risk of serious  consequences. The Public Health Security and Bioterrorism Preparedness  and Response Act of 2002 (the Bioterrorism Act) required drinking water  utilities serving populations greater than 3,300 to complete vulnerability  assessments by June 2004. Wastewater facilities are not required by law to  complete vulnerability assessments. Congress has considered bills that  would have encouraged or required wastewater treatment plants to assess  vulnerabilities, but no such requirement has become law.
In our March 2006 report on wastewater facility security efforts, we found  that many large wastewater facilities have either completed a vulnerability  assessment or had one underway. Of the 206 large wastewater facilities  that responded to our survey, 106 facilities—or 51 percent—reported that  they had completed a vulnerability assessment or were currently  conducting one. Several other facilities indicated they had conducted or  planned to conduct other types of security assessments. Facilities cited  several reasons for completing a vulnerability assessment or some other  type of security assessment, but most—roughly 77 percent—reported  doing so on their own initiative. Many facilities indicated they were  combined systems—facilities that manage both drinking water and  wastewater treatment. As such, 37 percent of facilities reported that they  did some type of security assessment in conjunction with the required  assessment for their drinking water facility.
The Clean Air Act requires wastewater facilities that use or store more  than 2,500 pounds of chlorine gas to submit to EPA a risk management  plan that lays out accident prevention and emergency response activities.
Under this act, EPA requires that about 15,000 facilities—including  chemical, water, energy, and other sector facilities—that produce, use, or  store more than threshold amounts of chemicals posing the greatest risk  to human health and the environment take a number of steps to prevent  and prepare for an accidental chemical release. EPA regulations  implementing the Clean Air Act require that the owners and operators of  chemical facilities include a facility hazard assessment, an accident  prevention program, and an emergency response program as part of their  risk management plans. The regulations required that a summary of each  facility’s risk management plan be submitted to EPA by June 21, 1999. The  plans are to be revised and resubmitted to EPA at least every 5 years, and  EPA is to review them and require revisions, if necessary.
section_title: Costs of Preparing Vulnerability Assessments and Risk Management Plans among Large Wastewater Facilities Vary Widely
paragraphs: Although accurate information on the costs of vulnerability assessments  and risk management plans is limited, available estimates suggest that  their costs vary considerably. A factor contributing to the cost differential  was whether they were contracted to third parties (such as engineering  consulting firms) or prepared in-house with existing staff. Despite higher  costs, some facilities preferred using contractors because their expertise  and independence lent credibility to their assessments, which may be  useful in obtaining support for security-related upgrades. Costs generally  did not relate to facility size, as measured by million of gallons of  wastewater treated per day.
subsections: section_title: Vulnerability Assessment Costs Depend Primarily on Whether a Contractor Is Used
paragraphs: The reported cost of preparing vulnerability assessments at the 20 large  wastewater facilities where we interviewed officials ranged from $1,000 to  $175,000. Whether the assessment was done in-house with existing staff or  contracted to a third party was a factor contributing to the cost  differences. Officials from several facilities told us they used contractors  to complete vulnerability assessments in 2002. For example, staff at the  Denver Metro Wastewater Reclamation District reported that a contractor  completed a vulnerability assessment in November 2002 for its Central  Treatment Plant, which treats 130 million gallons of wastewater per day, at  an estimated cost of $175,000. Of this cost, $100,000 was for the  contractor, and $75,000 was estimated for in-house staff time.
Other large wastewater facilities that reported completing vulnerability  assessments in 2002 were part of combined systems that provide both  drinking water and wastewater services. These systemwide vulnerability  assessments were done before the 2002 Bioterrorism Act required drinking  water utilities serving populations greater than 3,300 to complete  vulnerability assessments by June 2004. The combined systems that  conducted systemwide vulnerability assessments include the following:    San Antonio Water System (San Antonio, Texas). According to  system staff, a contractor completed a systemwide vulnerability  assessment for all its drinking water, wastewater, and related  infrastructure in August 2002 for $112,000. Staff did not provide an  estimate of in-house costs related to the assessment, but prorated the  wastewater treatment plants costs related to this contract at $37,000:  $25,000 for its Dos Rios plant, which treats 70 million gallons per day;  $5,000 each for its Leon Creek and Salado Creek plants, which treat 33  million gallons per day; and $2,000 for its Medio Creek plant, which  treats 5 million gallons per day.
The Phoenix Water Services Department (Phoenix, Arizona).
According to department staff, a contractor completed a systemwide  vulnerability assessment for its five drinking water plants, three  wastewater plants, and related infrastructure in November 2002 for  $479,725. Staff did not provide an estimate of in-house cost related to  the assessment, but estimated the contract costs related to its largest  wastewater treatment plant, the 91st Avenue Sewage Treatment Plant,  which treats 140 million gallons per day, to be $100,000.
Fort Worth Water Department (Fort Worth, Texas). According to  department staff, a contractor completed a systemwide vulnerability  assessment for its four drinking water plants and one wastewater  treatment plant in December 2002 at a cost of $292,300. Staff did not  provide an estimate of in-house cost related to the assessment, but  estimated the contract costs related to its Village Creek Wastewater  Treatment Plant, which treats 96 million gallons per day, at $73,075.
Wastewater facility managers cited several reasons for using contractors  to complete vulnerability assessments. Staff with the Phoenix Water  Services Department told us they used contractors for their vulnerability  assessment because a citywide policy required that contract services be  used whenever possible. Staff at other wastewater facilities told us that,  despite the higher costs, they preferred to use contractors because of their  expertise. According to a wastewater security official, contractor expertise  and independence can give contractor findings and recommendations  greater credibility with utility governing boards that determine spending  priorities.
One manager told us that he used a contractor for a 2002 vulnerability  assessment because risk management software and tools were not yet  available. After the events of September 11, 2001, EPA provided funding to  the Association of Metropolitan Sewerage Agencies to develop software,  called the Vulnerability Self Assessment Tool (VSAT), for water utilities to  use to develop vulnerability assessments. According to a Water  Environment Federation (WEF) official, VSAT became available in June  2002. This official also said that EPA provided funding to WEF to provide  training workshops to wastewater utilities on how to use VSAT to conduct  vulnerability assessments beginning October 2002.
According to interviews with wastewater facility managers, large  wastewater facilities that prepared vulnerability assessments in-house  with existing staff reported lower costs for preparing the document. These  include the following:    City of Ventura Public Works Department (Ventura, California).  According to facility staff, in-house staff completed a vulnerability  assessment in March 2003 for the Ventura Water Reclamation Facility,  which treats 9 million gallons per day, at a cost of roughly $1,000 in  staff time. Facility staff participated in VSAT training sponsored by  EPA and completed the assessment using this tool.
City of Fort Wayne Utilities Division (Fort Wayne, Indiana).
According to facility staff, in-house staff completed a vulnerability  assessment in November 2005 for the Fort Wayne Water Pollution  Control Plant, which treats 43 million gallons per day, at undetermined  staff time. Facility staff participated in VSAT training and updated a  previous risk assessment prepared for the facility by a contractor in  2000 at a contracted cost of $10,000.
City of Eugene Wastewater Division (Eugene, Oregon). According to  facility staff, in-house staff completed a vulnerability assessment in  October 2005 for the Eugene/Springfield Regional Water Pollution  Control Facility, which treats 38 million gallons per day, for about  $2,000 in staff time.
City of Cedar Rapids Department of Water Pollution Control (Cedar  Rapids, Iowa). According to facility staff, in-house staff completed a  vulnerability assessment in January 2007 for the Cedar Rapids  Wastewater Treatment Plant, which treats 35 million gallons per day,  for about $5,000 in staff time.
Detroit Water and Sewerage Department (Detroit, Michigan).
According to department staff, in-house staff completed a vulnerability  assessment in January 2005 for the Detroit Wastewater Treatment  Plant, which treats 700 million gallons per day, for about $20,000 in  staff time.
section_title: Risk Management Plan Costs Also Influenced by Use of Contractors
paragraphs: Costs to prepare risk management plans ranged from less than $1,000 for  facilities that completed the plan in-house to over $31,000 for facilities that  used contractors. Costs to update risk management plans were generally  less, ranging from less than $1,000 to $20,000 depending upon whether  facilities used in-house staff or contractors.
Costs were generally higher at facilities that used contractors. These  include the following:    The Phoenix Water Services Department (Phoenix, Arizona).
According to department staff, a contractor completed risk  management plans for all the system’s drinking and wastewater  facilities in 1999 for $230,086. Costs for the 91st Avenue Sewage  Treatment Plant were prorated at $28,761. Department staff said a  contractor updated the 91st Avenue plant’s risk management plan in  2004 for $20,000.
Fort Worth Water Department (Fort Worth, Texas). According to  department staff, a contractor completed risk management plans for all  of the department’s drinking water and wastewater facilities in 1999 for  $124,718. Costs related to the Village Creek Wastewater Treatment  Plant’s risk management plan were prorated at $31,100. Department  staff reported that the contractor later updated these risk management  plans for $18,040 in 2004, $4,510 of which was for the Village Creek  plant.
City of Fort Wayne Utilities Division (Fort Wayne, Indiana).
According to facility staff, a contractor completed a risk management  plan in 2001 for the Fort Wayne Water Pollution Control Plant for  $16,000. Facility staff reported a contractor updated the plan in 2005  for $6,000.
South Central Regional Wastewater Treatment and Disposal Board  (Delray Beach, Florida). According to facility staff, a contractor  completed a risk management plan in 1999 for the South Central  Regional Wastewater Treatment and Disposal Plant, which treats 18  million gallons per day, for $10,000. Facility staff reported a contractor  updated it in 2006 for $2,000.
City of Portland Bureau of Environmental Services (Portland,  Oregon). According to bureau staff, a contractor completed a risk  management plan in 1999 for its Columbia Boulevard Wastewater  Treatment Plant, which treats 143 million gallons per day, for $30,000.  Bureau staff reported they updated the plan using in-house staff in 2004  for $10,000 in staff time.
Other large wastewater facilities that prepared risk management plans in- house with existing staff reported lower costs for preparing the  documents. These include the following:    San Antonio Water System (San Antonio, Texas). According to  system staff, in-house staff completed a risk management plan in 1999  for the Dos Rios Wastewater Treatment Plant for between $5,000 and  $10,000 in staff time. In-house staff updated the plan in 2004 for less  than $1,000 in staff time.
City of Cedar Rapids Department of Water Pollution Control (Cedar  Rapids, Iowa). According to facility staff, in-house staff completed a  risk management plan in January 2000 for the Cedar Rapids  Wastewater Treatment Plant for $5,000 in staff time. In-house staff  updated the plan in 2004 for about $250 in staff time.
According to district staff, in-house staff completed a risk management  plan in 1999 for $10,000 in staff time. In-house staff updated the plan in  2006 for about $1,000 in staff time.
City of Savannah Water and Sewer Bureau (Savannah, Georgia).
According to facility staff, in-house staff completed a risk management  plan in 1999 for the President Street Water Pollution Control Plant,  which treats 17 million gallons per day, at a cost of only $150 in staff  time. In-house staff updated the plan in 2006 for about $130 in staff  time.
section_title: Costs of Converting to Alternative Disinfection Methods at Large Wastewater Facilities Depend on the Method Used and Other Factors
paragraphs: Large wastewater facilities that convert from chlorine gas disinfection to  alternative disinfection processes incur widely varying capital costs, which  generally depend on the alternative treatment chosen and facility size.  Other factors that affect capital costs include the characteristics of  individual facilities, such as whether existing structures can be used, and  local factors, such as building costs. Alternative disinfection processes  may also pose higher annual operating costs than chlorine gas. However,  these costs may be offset, at least somewhat, by savings in training and  labor costs, and regulatory burdens associated with the handling of  chlorine gas. Some facilities even reported or projected net annual cost  savings related to wastewater disinfection.
subsections: section_title: Disinfection Method Chosen, Facility Size and Characteristics, and Other Factors Determine Capital Conversion Costs
paragraphs: The 23 large wastewater facilities that we interviewed reported capital  costs for chlorine conversion ranging from $646,922 to just over $13  million. Table 1 identifies the 23 large wastewater facilities that recently  converted or plan to convert from chlorine gas to another disinfection  method and their reported and planned capital conversion cost.
As shown in the table, 17 of the 23 facilities converted or plan to convert  to sodium hypochlorite delivered in bulk to the facility. Officials with  several of these facilities told us they considered ultraviolet disinfection,  but chose delivered sodium hypochlorite because of its lower capital  conversion costs. The remainder converted or plan to convert to sodium  hypochlorite generated on-site or ultraviolet light. None of the facilities we  contacted adopted ozone.
Interview responses indicate that several factors affect the cost of  conversion; among these are disinfection method chosen, facility size, key  facility characteristics such as available buildings, and whether the  conversion was permanent or temporary, as follows.
subsections: section_title: Disinfection Method
paragraphs: Generally, conversion to delivered sodium hypochlorite has the lowest  capital costs, followed by sodium hypochlorite generated on-site, and  followed again by ultraviolet light. This observation is supported by cost  estimates in the Chlorine Gas Decision Tool, a software program released  by DHS in March 2006. The decision tool was designed to provide water  and wastewater utilities with the means to conduct assessments of  alternatives to chlorine gas disinfection. DHS cautions that the final costs  of the disinfection systems will depend on project design details, actual  labor and material costs, competitive market conditions, actual site  conditions, final project scope, implementation schedule, continuity of  personnel and engineering, and other variable factors. With these  caveats, the decision tool estimates that for a wastewater facility with an  average disinfection flow of 10 million gallons per day and a peak  disinfection flow of 20 million gallons per day, capital costs for conversion  to delivered sodium hypochlorite would amount to $533,000, on-site  generation of sodium hypochlorite would total $1,238,000, and ultraviolet  disinfection would reach $1,526,000.
Our interviews with wastewater facilities provide specific examples of  conversion costs. For example, managers of the Chesapeake-Elizabeth  Treatment Plant, which treats 21 million gallons per day and serves  customers in Virginia Beach, Virginia, reported spending an estimated  $1,225,000 in 2004 converting to bulk sodium hypochlorite disinfection.  Managers of the comparably sized Western Branch Wastewater Treatment  Plant, which treats 20 million gallons per day and serves customers in  Laurel, Maryland, estimated that they will spend $4 million converting to  ultraviolet light disinfection by January 1, 2008. Managers of the Western  Branch plant indicated that one reason they chose the more expensive  ultraviolet treatment option over bulk deliveries of sodium hypochlorite  was to avoid the risk to local traffic that could result from additional  deliveries to the plant. Plant managers indicated that because sodium  hypochlorite degrades more quickly than chlorine gas, truck deliveries  would increase under a disinfection system using sodium hypochlorite.  They also noted that ultraviolet light disinfection would eliminate the need  for the facility to handle and store significant amounts of hazardous and  corrosive chemicals.
section_title: Facility Size
paragraphs: In addition to disinfection method chosen, facility size can also influence  capital conversion costs. In general, larger facilities spend more  converting to alternative disinfection methods. For example, because  larger facilities process a greater flow of wastewater, converting to  delivered sodium hypochlorite would require a larger sodium hypochlorite  storage building or buildings relative to a smaller facility. It may also  require additional pumps, instrumentation, and piping to deliver treatment  chemicals to a greater number of contact tanks. Importantly, the largest  facilities also tend to serve high-cost urban areas, and their conversion  costs reflect the higher costs for construction materials and contract labor  in these markets.
For example, the Blue Plains Wastewater Treatment Plant, which treats  307 million gallons per day and serves over 2 million customers in the  Washington, D.C., metropolitan area, converted from chlorine gas to  delivered sodium hypochlorite in 2003 at a cost of almost $13 million.  According to facility managers, the facility temporarily converted from  chlorine gas to delivered sodium hypochlorite in April 2002 at a cost of  $500,000, primarily for storage tanks, pumps, piping, and related  instrumentation. It completed the permanent conversion in October 2003  at an added cost of about $12.5 million, which included the purchase of  additional storage tanks, related pumps, piping and instrumentation, and  the construction of storage facilities for sodium hypochlorite and sodium  bisulfate (used for dechlorination).
section_title: Other Key Facility Characteristics
paragraphs: In addition to facility size, other physical characteristics related to  individual facilities also play a large role in conversion costs. For instance,  the availability of usable buildings on facility grounds will determine  whether a facility needs to construct, expand, or update a building to  properly house sodium hypochlorite and its associated metering  equipment. In addition, the distance between the storage building and  treatment tanks will determine the amount of piping needed to deliver  stored sodium hypochlorite to the treatment tanks. An example comes  from the Hampton Roads Sanitation District which provides wastewater  treatment to approximately 1.6 million people in 17 cities and counties in  southeast Virginia, including the cities of Newport News, Norfolk, Suffolk,  Virginia Beach, and Williamsburg. In 2004, the sanitation district converted  from chlorine gas to bulk sodium hypochlorite disinfection at two of its  plants—the Nansemond Treatment Plant, which treats 17 million gallons  per day for the city of Suffolk, and the previously mentioned Chesapeake- Elizabeth plant, which treats 21 million gallons per day. The Nansemond  plant conversion cost an estimated $1.65 million, while the slightly larger  Chesapeake-Elizabeth plant conversion cost about $1.2 million. Costs  were higher at the Nansemond plant because a building needed to be  constructed for sodium hypochlorite storage, while the Chesapeake- Elizabeth plant had an existing building that only needed to be upgraded  to properly store the chemical.
Federal discharge permit requirements related to individual treatment  facilities can also influence conversion costs. Certain wastewater facilities  may be allowed higher chlorine residuals in treated effluent because they  discharge into less sensitive waters. Often, these facilities do not have to  dechlorinate wastewater, saving the facility the cost of dechlorination  chemicals, equipment, and storage. For example, the Philadelphia-area  Southeast and Northeast Wastewater Treatment Plants, which treat 90 and  190 million gallons per day, respectively, need only to chlorinate water  prior to discharging into the Delaware River. Both plants were converted  to delivered sodium hypochlorite—the Southeast plant in 2006 at an  estimated cost of $1.9 million and the Northeast plant in 2003 at an  estimated cost of $2.6 million. In contrast, the Baltimore-area Back River  Wastewater Treatment Plant, which treats 150 million gallons per day and  discharges into the ecologically sensitive Chesapeake Bay, must chlorinate  and dechlorinate its wastewater before discharge. This facility converted  to delivered sodium hypochlorite in 2004 at a reported cost of $3.3 million.
section_title: Temporary Conversions
paragraphs: Finally, some facilities have reduced conversion costs in the short term  through temporary conversions. For example, the Metropolitan Sewer  District of Greater Cincinnati decided to convert its Mill Creek Wastewater  Treatment Plant, which treats 120 million gallons per day, from chlorine  gas to sodium hypochlorite disinfection soon after September 11, 2001.  According to the plant manager, by mid-October 2001, the facility had  begun disinfecting with sodium hypochlorite by hooking up a rented  sodium hypochlorite trailer to its disinfection system at a cost of $25,000.  By May 2002, the facility had completed an interim conversion to sodium  hypochlorite by purchasing and installing two 8,000 gallon outdoor storage  tanks for sodium hypochlorite at a cost of $60,000. According to the plant  manager, this interim disinfection system is still in use today, though the  plant intends to permanently convert to delivered sodium hypochlorite in  2008 or 2009 at an estimated cost of $3 million. The plant manager said the  permanent conversion would include an unloading station for sodium  hypochlorite deliveries and a new storage building for the chemical and  related instrumentation. The plant manager said the new storage building  was needed to reduce the decay of stored sodium hypochlorite. The plant  manager added that the storage building and additional piping would  improve plant safety because it would allow for central storage and  delivery of sodium hypochlorite. Currently, sodium hypochlorite deliveries  are made at several plant locations for odor control which, according to  the plant manager, increase the odds the chemical may be mishandled and  accidentally mixed with other reactant chemicals used at the plant, such  as ammonia.
Similarly, the Eastern Water Reclamation Facility, which treats 16 million  gallons per day and provides service to Orange County, Florida, converted  from chlorine gas to sodium hypochlorite disinfection at a cost of $60,000  in November 2001 through the addition of outdoor storage tanks and  related pumps. According to the plant manager, the facility may consider  additional changes in the future, such as permanent sodium hypochlorite  storage or on-site generation.
section_title: Changes in Annual Costs Vary Widely, with Some Facilities Reporting Savings
paragraphs: Changes in annual costs related to disinfection treatment conversions  were hard to measure due to lack of data. Many facilities we interviewed  were unable to provide complete information on annual costs related to  disinfection before and after converting from chlorine gas. Available data  show that annual chemical costs related to disinfection increased for  facilities that converted to delivered sodium hypochlorite, because sodium  hypochlorite costs more than chlorine gas. Available data also show that  electrical costs related to disinfection increased for facilities that  converted to on-site generation of sodium hypochlorite or ultraviolet light  treatment, however these facilities also saw large reductions in chemical  costs. Available data also show that increases in annual costs related to  disinfection were offset somewhat by savings in training and regulatory  requirements, as several facilities that converted reported a reduced need  for staff time devoted to complying with the EPA risk management  planning that was required when the plant used chlorine gas.
A few facilities were even able to report or project annual savings due to  the disinfection conversion. For example, the wastewater treatment  manager of the Columbia Boulevard Treatment Plant, which treats 143  million gallons per day and provides wastewater service to Portland,  Oregon, estimated that annual costs related to disinfection fell by over  $100,000 after the plant completed a 2005 conversion from chlorine gas to  delivered sodium hypochlorite disinfection. According to the wastewater  treatment manager, increases in disinfection chemical costs for the plant  were more than offset by reductions in electrical, labor, and training costs.  Electrical power costs fell because the plant no longer had to power  chlorine gas evaporators, which heat and help convert the pressurized  liquid into gas before it is injected into the waste stream. In contrast,  sodium hypochlorite is fed into the waste stream via less energy-intensive  pumps. Labor and training costs also fell because the plant no longer had  to meet the Occupational Safety and Health Administration’s (OSHA)  Process Safety Management of Highly Hazardous Chemicals standard,  and risk management and emergency response planning costs associated  with the use of chlorine gas were eliminated.
In another example, the South Central Regional Wastewater Treatment  and Disposal Plant, which treats 18 million gallons per day for customers  in the cities of Delray Beach and Boynton Beach, Florida, predicts that it  too will achieve annual savings once it converts from chlorine gas to  sodium hypochlorite generated on-site, which it anticipates completing in  September 2007. According to the Executive Director of the South Central  Regional Wastewater Treatment and Disposal Board, potential disruptions  of sodium hypochlorite delivery during hurricane seasons motivated them  to begin generating their disinfection chemicals on-site. The plant’s most  recent fiscal year operating and maintenance budget for disinfection is  estimated to be roughly $307,000 for chlorine gas and associated costs  including equipment and maintenance, labor, and risk management  planning. Postconversion annual operating and maintenance costs for  disinfection are estimated to fall to $205,000 in the 2008 calendar year,  primarily due to the suspension of chlorine gas purchases.
section_title: Agency Comments and Our Evaluation
paragraphs: We provided a draft of this report to EPA for review and comment. In its  letter, reproduced in appendix II, EPA concurred with the results of the  report. EPA’s Water Security Division in the Office of Ground Water and  Drinking Water provided technical comments and clarifications that were  incorporated, as appropriate.
As agreed with your office, unless you publicly release the contents of this  report earlier, we plan no further distribution until 30 days from the report  date. At that time, we will send copies of this report to the appropriate  congressional committees; interested Members of Congress; the  Administrator, EPA; and other interested parties. We will also make copies  available to others on request. In addition, the report will be available at  no charge on the GAO Web site at http://www.gao.gov.
Should you or your staff need further information, please contact me at  (202) 512-3841 or stephensonj@gao.gov. Contact points for our Offices of  Congressional Relations and Public Affairs may be found on the last page  of this report. GAO staff who made major contributions to this report are  listed in appendix III.
section_title: Appendix I: Scope and Methodology
paragraphs: To identify the costs of preparing vulnerability assessments and risk  management plans, we conducted structured telephone interviews with a  select sample of large wastewater facilities identified as having completed  these documents in our March 2006 report. Our March report identified  106 large facilities that reported they had prepared vulnerability  assessments or had one underway, and 85 facilities that were required to  prepare risk management plans because they currently used chlorine gas  as a disinfectant. From these two groups, we identified 47 facilities that  reported that they had prepared vulnerability assessments and currently  use chlorine. Of this universe, we chose a nonprobability sample of 25  facilities to assure geographic dispersion and adequate variation in size,  since these factors were likely to influence their costs. We completed  structured interviews with 20 of the remaining 25 facilities. We sent an  interview schedule in advance of each of the interviews. We completed the  structured interviews between November 2006 and February 2007.  Reported costs included both actual and estimated costs. For estimated  costs, we asked facility managers to explain how they arrived at these  estimates. Reported costs were not adjusted for inflation.
To identify the costs incurred by wastewater facilities in converting from  gaseous chlorine to an alternative disinfection process, we conducted  structured telephone interviews with a nonprobability sample of 26 of the  38 large facilities identified in the March report as having recently  converted or planning to convert from chlorine gas to an alternative  disinfection process. We sent an interview schedule in advance of each of  the interviews. We completed the structured interviews between October  2006 and February 2007. Reported costs included both actual and  estimated costs. For estimated costs, we asked facility managers to  explain how they arrived at these estimates. Reported costs were not  adjusted for inflation. We also conducted site visits with some of the  facilities. Where available, we gathered documentation, such as capital  plans, from these facilities in order to document conversion costs. We  supplemented the cost information we gathered at individual wastewater  facilities with information obtained at the Environmental Protection  Agency, the Department of Homeland Security, nongovernmental  organizations, and industry representatives. We determined that reported  cost data were sufficiently reliable to provide useful information about the  costs for preparing vulnerability assessments, risk management plans, and  conversions from gaseous chlorine and the factors that affect these costs.
We conducted our work between August 2006 and March 2007 in  accordance with generally accepted government auditing standards.
section_title: Appendix II: Comments from the Environmental Protection Agency
section_title: Appendix III: GAO Contact and Staff Acknowledgments
subsections: section_title: GAO Contact
section_title: Acknowledgments
paragraphs: In addition to the contact named above, Jenny Chanley, Steve Elstein,  Nicole Harris, Greg Marchand, Tim Minelli, Alison O’Neill, Daniel Semick,  and Monica Wolford made key contributions to this report.