Applying a Risk Based Approach in Disposal of Hazardous Waste – Mongolia
The Millennium Challenge Account- Mongolia (MCA-M) in 2010 identified hazardous materials and waste as a major concern to being able to successfully complete compact projects. MCA-M along with the assistance of the Millennium Challenge Corporation (MCC) developed a risk based approach to resolving this problem which was applied to each step of the cradle to grave pathway to ensure the protection of human health and the environment. One of the more challenging aspects of this process was achieving disposal of the hazardous waste generated from the Compact projects.
This challenge was driven by several factors including:
• A lack of regulations governing the handling,
• Management and disposal of hazardous waste,
• A lack of capacity in terms of a suitable facility to accept hazardous waste for disposal and
• A lack of comprehension of the processes and treatment technologies available to eliminate and mitigate risks to people and the environment.
MCC and MCA-Mongolia working cooperatively, in association with both government ministries and the city of Ulaanbaatar, where able to overcome these obstacles and apply a risk based approach that allowed for the safe disposal of compact generated hazardous waste in the UB municipal landfill, Naran Enger. This paper summarizes this process.
Understanding the Human Health and Environmental Risk pathways
Risk pathways generally consist of three elements:
• A source
• A pathway, which includes:
– Transport media
– Exposure point
– Route of exposure
• A receptor population
Fundamental eliminating a risk is to break the pathway from the source to the receptor. This can be accomplished by a variety of actions or combination of actions involving one or more of the pathway elements.
As applied in defining an acceptable disposal approach for the hazardous waste associated with the MCA-M Compact projects risk-based approach means to develop an appropriate response action that will break the risk pathway, taking into account the most cost-effective solution to mitigate or abate the risk. Any strategy for the disposal of hazardous waste must consider:
• the risks presented by the waste,
• the characteristics of the waste,
• determine what, if any, treatment is required to reduce/eliminate toxicity and/or remove from pathway
• perform any necessary treatment to be protective of people and the environment
• the final form of the waste
• certify that the final waste disposal form has been meet and
• the treated waste is acceptable for disposal
The implementation of a successful strategy will include the application of good science and engineering as well as regulatory and business operational components.
The sources of risk associated with the wastes generated from the MCA projects emanated from lead-based paint, friable asbestos containing materials (ACM), mercury in electrical fixtures, polychlorinated hydrocarbons (PCBs) and bitumen.
Risks can be further separated into two broad categories. Short term, acute risks, which on Compact projects can generally be associated with the construction period of a project. The population at risk is generally the construction workers involved in the project and the casual visitor to the construction site. Long term, chronic risks are generally associated with the operational period of the project which includes the daily work force and visiting public. Risks can have cumulative effects when more than one source is present. Risks can also extend beyond the immediate project site to be regional and/or transboundary. Risk can be receptor specific based upon the pathway.
MCA-M established a process to mitigate risks associated with the waste generated from its project that considered a lack of regulations, a lack of suitable disposal capacity and a lack of understanding of the risk. In the absence of any clear governmental regulations, MCC and MCA-M in the initial periods of the compact worked diligently to develop guidelines, processes and procedures which defined the framework under which all hazardous materials and waste generated by the Compact would be handled and managed.
The guidelines recognized the need for all waste to find a way safely into an acceptable final disposal site thus breaking the source-receptor pathway at the project by removing the source. However, interim storage and disposal of untreated hazardous waste creates a new source location that creates a new pathway to receptors at the storage and disposal site. It was quickly realized that many of the waste materials; flooring, window sills, doors, and radiators painted with lead-based paint were highly desirable and could be easily recycled into the community, creating a new risk pathway. Introducing these materials back into the population had to be avoided. This necessitated further consideration of treating the wastes to neutralize their hazard and locating storage and disposal sites which could be under strong institutional control to prevent scavenging and reusing the contaminated materials.
The UB municipal landfill, Naran Enger, was a candidate as a final disposal site but initial discussions with the city indicated they were not willing to accept hazardous waste at this municipal landfill. Rural dump site were not an acceptable option. NEMA had undertaken a program to address legacy military and chemical stock piles left by the former Soviet Union but did not feel these wastes were compatible. Transboundary shipments to China, or Russia were determined to not be feasible.
In the intermediate timeframe of the compact negotiations and discussions with NEMA and the City of Ulaanbaatar where carried out to achieve an agreeable solution to how to either provide safe storage of hazardous waste until a suitable disposal site waste established or define an acceptable process for treating the waste to an acceptable level that would be protective of human health and the environment so that the waste could be disposed of in a municipal landfill.
After nearly two years of negotiations and discussions MCA-Mongolia proposed a risk based treatment and disposal approach to the City of Ulaanbaatar that was consistent with international best management standards considering the characteristics of the Compact generated wastes.
To this end MCA identified the following steps to create an “as left” waste configuration that met MCC’s objectives:
1. Establish a safe and secure interim storage site until a final disposal solution can be identified. The City of Ulaanbaatar agreed to provide an interim storage site within the Naran Enger landfill which provided a safe, secure storage facility while the challenge of finding a final disposal site was undertaken. MCA constructed a storage pad, placed shipping containers on the pad to receive the waste and erected a security fence around the storage site control access.
2. Transfer all hazardous waste generated during project renovation and construction activities are placed in shipping container boxes for safe storage.
In the spring of 2013 with less than nine months to the end of the Compact MCA-Mongolia support by MCC provided a technical basis that demonstrated to the City that encapsulation and burial of these wastes would render then safe. MCA-Mongolia and the City reached an agreement to allow final treatment and disposal of the hazardous waste to occur at the Naran Enger landfill.
The City identified a specific location within the landfill as the disposal site. MCA relocated one shipping container box to the disposal site and transferred all waste into this container. The container was sealed, access portals were cut into the top and concrete grout was introduced into the container. The treatment process encapsulated all hazardous waste in a monolith of concrete. Approximately one meter of soil was place over the entire structure.
This treatment and disposal process will leave the hazardous waste in an “as left “condition that achieves MCC’s objectives because it breaks the direct contact pathway for people and the environment to come in contact with the waste and provides an alternative to requiring strong institutional controls because access to the waste is eliminated. Encapsulating the waste in concrete makes it virtually impossible for the material to be successfully retrieved intact and thus re-cycled. Protection of surface and groundwater resources from these wastes is achieved because there is a low waste volume, the wastes have limited leachability and there are no free liquids. Encapsulation further minimizes water infiltration through the waste for the foreseeable future.
The final treatment and disposal was accomplished over a two day period in June 2013.
Dr. Paul Seeley, President, Cenibark International, Inc.
MSc. Naran-Undrakh Baatar, Environmental specialist of MCA-Mongolia.