EMS Development at Nogales International Wastewater Treatment Plant: Managing Environmental Aspects Beyond Borders

WEFTEC®.06

Johanna C. Jobin,* Carlos Peña, Jr., P.E.** *CDM One Cambridge Place 50 Hampshire Street Cambridge, MA 02139

**U.S. Section, International Boundary and Water Commission

ABSTRACT

The International Boundary and Water Commission (IBWC) is responsible for applying the boundary and water treaties between the United States and Mexico. The United States Section of the International Boundary and Water Commission (USIBWC) operates the Nogales International Wastewater Treatment Plant (NIWTP) that provides secondary treatment for wastewater generated in Nogales, Arizona and Nogales, Sonora (Mexico). Located 9 miles north of the international border, the NIWTP faces increasing challenges in managing the plant due to the rapid industrial, economic, and demographic growth along the border that places a significant impact on the region’s environment. These responsibilities have earned the IBWC international recognition as a leader in managing transboundary waters and as a model of effective international cooperation.

In its efforts to develop an environmental management system (EMS) to meet the requirements of the United States’ federal government’s Executive Order 13148 and the International Organization for Standardization EMS standard ISO 14001:2004 (ISO 14001), the NIWTP identified its significant environmental aspects that must be managed through effective transboundary water management programs. The NIWTP established objectives and targets to minimize its environmental impact and developed environmental management programs to increase international cooperation, education, and communication between the sister cities. As a result, the EMS development is a unique approach in managing significant aspects that the NIWTP has no direct control over and is a model for working with entities across the border region to find solutions to transboundary environmental problems.

KEYWORDS

Environmental management system, transboundary water management, environmental aspects.

INTRODUCTION

The International Boundary and Water Commission (IBWC) is internationally recognized as a leader in managing transboundary waters and as a model of effective international cooperation. Designated under the Water Treaty of 1944 that provided the legal framework for managing transboundary waters, the agency is responsible for applying the boundary and water treaties between the United States and Mexico. Through the coordination of a United States Section and a Mexican Section, la Comisión Internacional de Limites y Aguas (CILA), the IBWC operates and maintains various border related infrastructure and environmental issues, including flood control, maintenance of the international border, sanitation, operation of dams, and the division and use of international waters (U.S. Section, International Boundary and Water Commission, 2006). Managing these transboundary issues takes a concerted effort and shared responsibility not only from the two IBWC counterparts, but also from the local and state agencies from both countries.

The United States Section of the International Boundary and Water Commission (USIBWC) is developing an environmental management system (EMS) to satisfy the requirements of Executive Order 13148 “Greening the Government Through Leadership in Environmental Management” (Federal Register, 2000) and to conform to the International Organization for Standardization EMS standard ISO 14001:2004 (ISO 14001) for continual improvement of environmental performance (American Society for Quality, 2005). Among other things, the ISO 14001 standard requires the identification of environmental aspects that an organization can control and those that it can influence (2005). Environmental aspects are an element of an organization’s activities, products, or services that can interact with the environment.

The USIBWC established an EMS fence line, or initial EMS limit, encompassing the El Paso, Texas headquarters office, the American Dam field office in El Paso, and the Nogales International Wastewater Treatment Plant (NIWTP) field office in Nogales, Arizona. Due to the differing functions of the three offices, the EMS development began with an initial environmental assessment at each facility in order to identify environmental aspects and significant environmental aspects (SEAs). SEAs are those aspects that can have a significant impact on the environment, whether positive or negative.

Given the scope and breadth of activities at the NIWTP, the SEA identification process revealed a range of environmental aspects from Mexico over which it has little or no control. Since the NIWTP receives wastewater from Mexico, some SEAs identified were ones that were not realistically in the plant’s control, but rather those that it could only influence.

Managing those SEAs at the NIWTP poses a real challenge because of the cultural differences within the U.S.-Mexico border region and the varying power and responsibilities among local, state, and federal agencies from both countries. Through the EMS, the NIWTP must seek ways to effectively address those issues that it does not have direct control over using existing border relations with their Mexican counterparts.

BACKGROUND ON IBWC AND NIWTP

After first creating the International Boundary Commission (IBC) in 1889 to serve as the solution for boundary and water problems, the United States and Mexican governments signed the Water Treaty of 1944 which reconstituted the IBC as the IBWC. The IBWC has responsibility for applying the boundary and water treaties between the United States and Mexico and settling differences that may arise out of these treaties (U.S. Section, International Boundary and Water Commission, 2006). As the premiere organization on the United States and Mexico border, the IBWC diplomatically resolves transboundary water, infrastructure, and related technical issues in a manner that benefits the social and economic welfare of the peoples on the two sides of the boundary and improves relations between the two countries (2006).

There are more than 1,952 miles of border between the United States and Mexico, encompassing the states of Texas, New Mexico, Arizona, and California and the Mexican states of Tamaulipas, Nuevo Leon, Coahuila, Chihuahua, Sonora, and Baja California (U.S. Section, International Boundary and Water Commission, 2004). Headquartered in El Paso, Texas, the United States Section has 11 field offices along the border and a liaison office at the U. S. Department of State in Washington, DC. Under its critical mission areas, headquarters maintains an operations department and engineering department, each directed by a principal engineer. Each field office, managed by a project manager and supported by engineering, operations, and administrative staff, is located at joint project sites or related operations of other field offices along the boundary to foster essential cooperation and coordination of activities.

One such field office is the Nogales International Wastewater Treatment Plant (NIWTP) that is co-owned by Nogales, Arizona, but operated by the USIBWC. The plant is adjacent and west of the Santa Cruz River/Nogales Wash confluence, approximately 9 miles from the international border. It provides secondary treatment for wastewater generated in the sister cities of Nogales, Arizona and Nogales, Sonora in Mexico, and discharges treated wastewater, or effluent, into the channel of the Santa Cruz River (Sprouse, 2005). This area is commonly referred to as Ambos Nogales in Spanish or both Nogales in English. The USIBWC in Mexico and Nogales, Arizona share the operating costs (U.S. Section, International Boundary and Water Commission, 2006).

The wastewater is conveyed northward from Nogales, Sonora and Nogales, Arizona to the NIWTP via a gravity collection system. The international outfall interceptor (IOI), located along the Nogales Wash, transports the combined flows from both communities to the NIWTP. The NIWTP has a maximum potential treatment capacity of 17.2 million gallons per day (mgd). The present sewage treatment of the plant is allocated between the sister cities with 9.9 mgd of capacity for Nogales, Sonora, and the remaining 7.3-mgd for Nogales, Arizona. Since 2000, the average flow to the plant remains relatively constant at around 15 mgd (CDM, 2005). Approximately 69 percent, currently exceeding the allocated capacity, of the plant’s influent flow originates in Nogales, Sonora and 31 percent originates in Nogales, Arizona (U.S. Section, International Boundary and Water Commission, 2005).

Employing oxygenated pond technology and chlorination/dechlorination for disinfection for 13 years, the wastewater goes through several treatment steps before the effluent is discharged into the Santa Cruz River. The plant’s treated effluent provides habitat along 10 miles of the river

corridor and replenishes the aquifers serving the Santa Cruz and Pima County communities (U.S. Environmental Protection Agency, 2005). Recent efforts have focused on upgrading the NIWTP to increase capacity as well as the IOI to replace it with a larger pipe to bring the plant into compliance with stricter federal and/or state discharge permit requirements and to meet expected growth demands on both sides of the border (U.S. Section, International Boundary and Water Commission, 2004). Figure 1 illustrates the location of the NIWTP, Nogales Wash, and IOI as they relate to the transboundary waters of the border region.

Figure 1 – Map of NIWTP and Surrounding Area

(CDM, 2006)

EMS DEVELOPMENT AT NIWTP

In order to minimize its operational impact on the environment and comply with all applicable environmental laws and Presidential Executive Orders, the USIBWC is establishing an EMS. The EMS satisfies the requirements of Executive Order (EO) 13148 “Greening the Government Through Leadership in Environmental Management” (Federal Register, 2000) and conforms to the ISO 14001 international standard for continual improvement of environmental performance (American Society for Quality, 2005).

In April of 2000, EO 13148 was promulgated to make federal agencies responsible for and take actions necessary to integrate environmental accountability into every day decision making and long-term planning. As stated in EO 13148, the USIBWC is required to develop and implement an EMS to “ensure that strategies are established to support environmental leadership programs, policies, and procedures and that agency senior level managers explicitly and actively endorse those strategies” (Federal Register, 2000).

EO 13148 requires federal agencies to:

• Conduct an agency-level EMS self assessment; • Implement an EMS at all appropriate federal agency facilities; • Include, and review and update annually, measurable environmental goals, objectives and targets; and • Incorporate EMS performance measures into the facilities audit protocols.

In order to meet these requirements, the USIBWC developed an overall EMS framework, including organization, processes, and tools based on its environmental policy, under which each field office will follow. The EMS organization consists of an EMS coordinator, responsible for EMS development and oversight, a steering committee, responsible for policy implementation and EMS integration into USIBWC procedures and operations, as well as a core EMS team comprised of the operations and engineering department staff and one representative from each field office. Representatives on the core team recommend staff members to participate on EMS implementation teams at their respective project sites. The implementation teams work closely with the core team members and are responsible for EMS implementation at their respective field offices. The field offices are intended to follow this framework, but are expected to identify environmental aspects and impacts, establish objectives and targets, and develop environmental management programs to fully implement the EMS at their own facility. The USIBWC’s EMS strategy is a common system that each field office can apply to its specific operations in helping to manage its environmental aspects.

The NIWTP began its EMS development by forming its organizational structure, naming a representative to the core EMS team and composing the implementation team, and establishing objectives and targets to manage identified SEAs. The core team representative is responsible for working with the implementation team to identify the NIWTP’s SEAs and to develop objectives and targets and environmental management programs. The implementation team is responsible for the daily EMS implementation activities at NIWTP. The two teams work together to make

sure the EMS implementation is ongoing and progressively improving NIWTP’s environmental performance, and report on the EMS status to the EMS Coordinator.

IDENTIFICATION OF ENVIRONMENTAL ASPECTS

In the early stages of EMS development, environmental aspects are identified to indicate the processes or activities that an organization needs to manage to reduce its environmental impact. Environmental aspects are an element of an organization’s activities, products, or services that can interact with the environment and have an actual or potential environmental impact. Once an organization identifies its environmental aspects, it can focus the management system on just those aspects that have a significant impact on the environment. SEAs are those elements of an organization’s activities, products, or services that have or can have a significant environmental impact. The SEAs should be addressed with priority in implementing the EMS.

Determining SEAs is not always a simple process, as in the case of the NIWTP, and depends on parameters an organization sets for itself. The process of identifying aspects should stay true to an organization’s given scope and should examine the inputs and outputs of past, existing, or planned activities, as well as evaluate those associated with normal, abnormal, or foreseeable emergency operating conditions (American Society for Quality, 2005). Taking those considerations into account, the organization will generate a list of aspects that is often quite lengthy, and will need to be hammered down to reveal those aspects that are more significant than others. In doing so, an organization may look at categories of aspects or those it can directly control versus influence.

According to the revised ISO 14001 standard, an organization should consider aspects that it has direct control over and those it can influence, though it is up to the organization to determine the degree to which it defines control and influence and the criteria to evaluate them. ISO 14001 defines aspects that an organization may only influence as those related to goods and services used by the organization and those related to products and services that it provides (2005). During the significance rating process at the NIWTP, it was revealed early that some of the significant aspects were those the plant could only influence, rather than directly control. In this case, the NIWTP defines control as aspects that can be managed directly by the plant, and influence as aspects that must be managed in conjunction with other entities.

The USIBWC developed a standard operating procedure (SOP) for the identification of environmental aspects and prioritization of SEAs. Through a series of workshops, members of the NIWTP’s EMS teams generated a list of work processes and activities that could have potential impacts on the environment. Since the plant has a wide array of services and operations, including an administrative building, laboratory, electrical panel control room, workshops, and storage areas, the two teams completed a process diagram for each area, identifying inputs (materials, information, tools), activities, and outputs (products, by-products, waste).

The completed process diagrams were used to list all the environmental aspects and potential impacts associated with the plant’s operations. In order to determine significance, the teams prioritized each aspect according to some pre-determined criteria and a rating system. Table 1 defines the 5 criteria used by the NIWTP.

Table 1 – Criteria for Significance

Category Definition Explanation The probability that an impact might occur, or how Probability of often it actually occurs will affect the significance of Frequency occurrence the impact. When evaluating severity of an impact, it is helpful to consider: proximity of impact to people or environmentally sensitive areas; toxicity of substances Severity Severity of impact involved; quantities of substances involved; effects from startup and shutdown conditions; duration of exposure or effects; size of the area affected; potential for migration of the hazard. Impacts subject to local, state, federal regulations are Federal, state, local Regulatory automatically significant. Situations involving a high regulatory concerns Requirements risk of noncompliance demand increased priority. When evaluating environmental risk, it is helpful to consider: proximity of impact to environmentally sensitive areas; toxicity of substances involved; Environmental Impact to local/global quantities of substances involved; effected from Risk environment startup and shutdown conditions; duration of exposure or effects; size of the area affected; potential for migration of the hazard. When evaluating human health risk, it is helpful to consider: proximity of impact to people; toxicity of Health and Impact to worker substances involved; quantities of substances involved; Safety Risk health and safety effects from startup and shutdown conditions; duration o exposure or effects; size of the area affected; potential for migration of the hazard.

For each aspect, the teams rated each criterion as high, medium-high, medium, medium-low, or low. The rationale for each rating was documented on a worksheet with the final list of SEAs forming after tallying the ratings in aggregate. The generated list of SEAs presented aspects that were not just tangible goods that their use could be controlled by the plant, but rather the inputs and outputs of the processes to make the plant’s product, treated wastewater, were wholly

affected by another country. That in turn uniquely shaped the development of the EMS because the EMS teams had to determine objectives and targets for improving the environmental performance of SEAs they knew would be a challenge.

CHALLENGES OF MANAGING TRANSBOUNDARY ASPECTS

From learning that some of its SEAs were aspects the plant could only influence, the NIWTP had to continue to seek ways to manage the real and potential transboundary environmental impacts from Mexico within the EMS (U. S. Environmental Protection Agency, 2005). One example of a SEA that the plant can only influence is the treatment of sewage from Mexico that has been found to contain industrial and infectious waste. Another SEA is that the plant provides disinfection of sewage release with the use of granulated chlorine in the Nogales Wash, the storm drain that flows northward through the urban areas of Nogales in both countries (U.S. Section, International Boundary and Water Commission, 2006). Because by nature the NIWTP is an end- of-pipe pollution treatment facility, the EMS teams need to focus on the inputs of its processes and find ways to work with the upstream entities across the border to find solutions in managing the SEAs and reduce their pollution at the source. Table 2 lists the SEAs identified at the plant and indicates which ones the plant has direct control over and those having only influence.

Table 2 – Significant Environmental Aspects

Direct Significant Environmental Aspects Influence Control Hazardous Waste Generation 9 Air Emissions 9 Chemical Handling and Storage 9 Combined Sewer Overflows Release 9 Contract Specifications Addressing Environmental Management 9 Damage to Natural Resources 9 Solid Waste Generation 9 Effluent 9 Fuel Use 9 Materials Use 9 Odors 9 Storage and Dispensing of Chlorine 9

Vectors 9 Obsolete Equipment 9

Combined Sewer Overflows Release

Combined sewer overflows (CSOs) release became a significant aspect because of its reoccurrences from ongoing construction in Mexico as well as its potential environmental and health risk from entering the Nogales Wash and contaminating the Santa Cruz River. Booming United States-Mexico trade under the 1994 North American Free Trade Agreement (NAFTA) has accelerated the growth of border manufacturing centers and sparked a rise in construction in Mexico, increasing the release of CSOs. Population in the Ambos Nogales region is expected to grow 67 percent in Santa Cruz County, Arizona and 86 percent in Nogales Sonora (Peach and Williams, 2000). The region’s hilly topography, variable precipitation, and uncontrolled urbanization has worsened flood control problems by increasing runoff, reducing the area of undeveloped floodplain, and introducing additional industrial and household pollutants (Varady, Ingram and Milich, 1995).

Due to deficiencies within the collection systems in Nogales, Arizona and Nogales, Sonora, certain amounts of untreated wastewater escapes into the groundwater table and into the Nogales Wash, a tributary of the Santa Cruz River. Periodically, wastewater flows exceed its capacity resulting in overflows of untreated sewage into the Nogales Wash, and during wet weather periods, it may also enter the Santa Cruz River (U. S. Environmental Protection Agency, 2000). Even though an informal agreement exists between the USIBWC and stakeholders to monitor the flows and fecal counts in combined sewer overflows, the NIWTP must continue to undertake sanitation work to perform repairs and maintenance to the border region’s wastewater infrastructure to prevent sewage flows from entering the United States.

Effluent

One specific challenge for the NIWTP is working to meet its Arizona Pollutant Discharge Elimination System (AZPDES) permit, particularly for total suspended solids (TSS), ammonia, and the high phosphate content of the influent coming from Mexico. Because of this regulatory issue and potential for contaminating the underlying aquifer, effluent became a significant aspect. Even though the effluent poses an overall positive environmental impact on the riparian habitat of the Santa Cruz River by providing regular surface flow for what would otherwise be a dry river bed, the effluent has appeared to limit populations of some riparian wildlife, including invertebrates and fish. (King, Zaun, and Velasco, 1999).

A root cause of the effluent not meeting Arizona water quality standards is the inconsistency of the upstream pretreatment programs as well as land use changes due to the decline in agriculture and the increase in industrial and residential use. As a means to correct this problem, the NIWTP needs to use existing communication channels for providing general environmental awareness to the local communities and its Mexican counterparts and for increasing participation in pretreatment programs for reducing harmful discharges at the source.

Storage and Dispensing of Chlorine

The storage and use of chlorine in the form of tablets poses another challenge since they are used in treatment of the Nogales Wash across the border in Mexico. The concern over uncontrolled wastewater discharges or untreated sewage into the Nogales Wash prompted the NIWTP to supply dry granulated chlorine for its disinfection (U.S. Section, International Boundary and Water Commission, 2004). After coordinating with local and state government agencies to supply the chlorine for the disinfection of flows in the Nogales Wash to the Nogales, Sonora Utility, Comisión de Agua Potable y Alcantarillado del Estado de Sonora (COAPAES), the plant handles chlorine in excess of 10,000 pounds-per-year with approximately less than 1,000 pounds transported to Mexico once per week. The NIWTP stores the chlorine in an on-site storage shed and employees from COAPAES transport it to treat the water in the Nogales Wash as it crosses into Arizona.

In this case, the storage and dispensing of chlorine became a significant aspect, not because the program manages a larger environmental aspect of the fugitive wastewater in the Nogales Wash, but from the potential environmental, health, and safety risks posed by the management and transportation of the chlorine.

USING THE EMS AS A SOLUTION

In the EMS development process, determining practical, yet attainable, objectives and targets, as well as environmental management programs for the 3 SEAs not under direct control, proved to be more difficult than the other aspects, since the plant could not directly manage them. The EMS teams realized that the plant plays a large role in using their influence over these SEAs to ensure their proper management and to minimize the impact on the environment. Developing the management system became a progression away from traditional wastewater treatment plant end-of-pipe thinking to an opportunity of improving upstream operational efficiencies for environmental gains.

Members of the team realized that even though the EMS is implemented locally at the plant, it requires border-wide coordination and planning. In order to best address these SEAs, the NIWTP focuses on a localized EMS approach that emphasizes local stakeholder engagement, building on existing programs, priority setting of objectives and targets, and EMS implementation. The NIWTP thus proposed practical objectives that the plant could work to attain to help manage the SEAs by exerting its influence. Table 3 lists the objectives and targets for those SEAs.

Table 3 – Objectives and Targets

Significant Environmental Aspects Objective Target

Increase communication and Establish bi-monthly meeting Combined Sewer awareness with Mexico about schedule about this issue Overflows Release Nogales Wash

Increase community awareness Establish external

about quality impacts of river communications program about Effluent water river water safety Develop SOPs for inventory management; Provide training Optimize existing chemical Storage and Dispensing and awareness to employees; management program to include of Chlorine Invite Mexico staff to inventory management participate in training and awareness

The NIWTP has the opportunity to use the EMS to manage those SEAs that it can control and influence. Effective internal and external communication is necessary for the NIWTP to implement the EMS and the only way to manage the SEAs over which the plant has influence. NIWTP management can use existing communication channels for educating the local communities and its counterparts in Mexico of the environmental policy and general environmental awareness. For example, the lagoons at NIWTP create habitat for many species of birds and is a local attraction for bird watchers, providing an opportunity to foster awareness and outreach to the local communities.

Combined Sewer Overflows Release

As part of USIBWC’s strategic plan for addressing technical transboundary management issues, the NIWTP is to use binational cooperation in improving border sanitation conditions and enhancing the quality and use of international waters in a manner that supports ecological needs and regional sustainable development (U.S. Section, International Boundary and Water Commission, 2004). Thus, the NIWTP is offering more support and expertise through awareness and education to Mexico for coping with the influent and managing CSOs.

The USIBWC has developed the Citizens’ Forum program, which NIWTP can use to educate the public and facilitate the exchange of information between border communities and leaders about USIBWC projects and related issues. This program is a domestic effort operating in 5 field office regions: Rio Grande, Lower Rio Grande, South Bay International Wastewater Treatment Plant (SBIWTP), Southeast Arizona, and the Colorado River. The program establishes community boards along the border region to assist the USIBWC with its outreach efforts. These public meetings enhance communication with border communities and leaders about IBWC projects and related issues. With 10 board members and IBWC staff from both sections, the Southeast Arizona Citizens’ Forum (SACF) serves Santa Cruz and Cochise Counties in Arizona and fosters discussion between the NIWTP and the general public, environmentalists, government agencies, municipalities, and other interested parties (USIBWC, 2002).

Effluent

In an effort to increase community awareness, the NIWTP is involved in a wastewater pretreatment program that provides information to the public and works with industrial and commercial operations on both sides of the border to reduce discharges of problem compounds

by adopting facility-specific pretreatment strategies. Pretreatment involves keeping wastewater free of harmful compounds such as pesticides, gasoline, oils, or metals that can disrupt the growth of beneficial microoganisms or pollute the downstream environment (U.S. Section, International Boundary and Water Commission, 2004). Through a binational committee, the program encourages industrial and commercial facilities to identify appropriate strategies, such as adopting cleaner manufacturing processes, to reduce discharges of harmful materials to the collection system (U.S. Section, International Boundary and Water Commission, 2005). Representatives of the committee include: the United States and Mexican Sections of the IBWC; United States Environmental Protection Agency (USEPA); the Arizona Department of Environmental Quality (ADEQ); the Arizona Department of Water Resources (ADWR); the City of Nogales, Arizona; Mexico’s National Water Commission, la Comisión Nacional de Agua (CNA); and the City of Nogales, Sonora’s Potable Water and Sewer Commission, Organismo Operador Municipal de Agua Potable (OOMAPASNS).

With this binational committee, the NIWTP also educates the surrounding communities of Nogales, Arizona and Nogales, Sonora in Mexico about general awareness for wastewater best practices through external communication methods like the newspaper and agency websites. The NIWTP is involved with environmental awareness and outreach programs that inform the general public about certain contaminants, like antifreeze, motor oil, fertilizer, and paint thinner, which should never be poured down the drain (2005). This approach is similar to the strategy for minimizing CSOs.

Storage and Dispensing of Chlorine

In an effort to improve sanitation of the Nogales Wash, the NIWTP supplies granulated chlorine to Mexico to reduce public health risk that occurs when maintenance problems cause sewage to enter the storm drain. In doing so, the NIWTP takes on another SEA that it must manage. Best practices for managing the storage area of chlorine include optimizing the existing chemical management program to include inventory management, but also to take precautionary measures when transporting the materials.

This objective is to be implemented through the development of standard operating procedures (SOPs) for chemical inventory management, best practices for transportation, increased training, and binational awareness to those employees maintaining the storage area, as well as those picking up the chlorine. Carrying the Material Safety Data Sheets (MSDS) during transportation of the products, maintaining the proper labels on containers, and reducing loads during inclement weather are ways for better managing the handling and dispensing of the chlorine and minimizing environmental as well as health and safety risks.

LESSONS LEARNED

1. EMS development at NIWTP demonstrated that environmental aspects do not always adhere to the initial fence line an organization sets for itself and may be transboundary in nature. Thus, in order to effectively manage these environmental aspects, it is important to delineate which ones an organization has direct control over and those that can be influenced in order

to move forward with the appropriate strategy for EMS implementation. Furthermore, managing environmental aspects of influence versus direct control can be of equal importance.

2. The difficulties of managing the aspects also stem from the varying local, state, and federal regulatory requirements posted by the border region. The requirements differ between the United States and Mexico. In the United States the ADEQ and ADWR share the regulatory authority, and in Mexico, the CNA is a federal regulatory authority. Even though constructive collaboration among these regulatory enforcement agencies yields better environmental performance, it is difficult to coordinate programs and monitoring activities.

3. It is interesting to note that the same mechanisms for pollution prevention were also the cause of some significant aspects. The NIWTP is by nature an end-of-pipe pollution prevention technology, but its environmental performance still hinged upon the inputs over which the plant had no full control. Furthermore, the granulated chlorine itself is a strategy for cleaning up contamination in the Nogales Wash, but it posed other environmental, health, and safety risks through its management and transportation.

4. If these local initiatives and upstream approaches are successful for the NIWTP, the USIBWC can incorporate these as it builds out its EMS to other treatment plant facilities, such as the SBIWTP and the approved development of a wastewater treatment plant in Tijuana, Baja California.

5. If the stakeholder engagement approach and sharing of knowledge and resources are successful for the NIWTP, the USIBWC can use this model in helping its other facilities on the border to manage transboundary environmental aspects.

CONCLUSIONS

Effective implementation of the NIWTP’s EMS hinges upon the plant’s ability to manage the SEAs that it has influence over, which present challenges for the plant. Under the EMS framework, the NIWTP must work towards minimizing its environmental impact through programs that increase binational cooperation, stakeholder engagement, and best practices to implement its environmental management programs.

In order to effectively manage its SEAs, the NIWTP must exert its influence through increased stakeholder engagement and education of the surrounding communities of Ambos Nogales about the environmental policy and general awareness for how citizens can influence wastewater quality. Public outreach opportunities, such as the Citizens’ Forum, are necessary for educating citizens what they can and cannot put down their drains. It is essential for the NIWTP to create and sustain these partnerships with upstream stakeholders to share knowledge and resources to significantly reduce the environmental impacts of the influent coming into the plant. The plant must maintain constructive collaboration with its Mexican counterparts to improve the environmental performance of the transboundary water issues.

Further roll-out of the EMS across the USIBWC field offices will follow the plant’s EMS development approach to managing transboundary environmental aspects. The EMS framework will provide the USIBWC with the tools to improve and sustain the environmental performance of the U.S.-Mexico border region.

ACKNOWLEDGMENTS

We would like to express our gratitude to Commissioner Carlos Marin and the USIBWC staff in their efforts for developing the EMS. Special thanks to the EMS team members at the NIWTP, including John Light, Glenn Hansel, Gerardo Federico, Alison Lamb, and Javier Castro. We also thank Peter Maynard, Tom Pedersen, Sarah Guemez, and Laura Keating of CDM for their assistance.

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