2020/21 KSP Policy Consultation Report: Sewage Management to Conserve Natural Protected Areas in Mexico
- Author Lee, Byung-Kook et al.
- Researchers
- Date 2021-11-30 00:00
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Sewage Management to Conserve Natural Protected Areas in Mexico.pdf Download
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Executive Summary
Byung-Kook LEE (Korea Environment Institute)
Mexico’s natural ecosystem is highly valued for conservation and is an important part of the country’s tourism industry. Although the Cancun region has experienced rapid population growth and urban development due to the tourism industry, sustainable development and management have not proceeded as originally planned. As a result, the environment and ecosystem of Nichupte Lagoon are being damaged due to insufficient sewage facilities and insufficient environmental regulations, and this is expected to cause great damage to the tourism industry.
As it was necessary to improve sewage management policies in order to effectively conserve nature reserves in Mexico, the CONANP under the SEMARNAT conducted a study based on Korea’s experience. In the study area, there were three large sewage treatment plants to treat sewage from the Hotel Zone. Because the impact of sewage treatment plants on the water quality and ecosystem of Nichupte Lagoon is very important, we focused our efforts on performing an in-depth analysis of the sewage facilities in order to improve efficiency and monitoring. In addition, based on the experience of Korea, policy recommendations in response to the demands of Mexican representatives have been prepared to strengthen the sewage management of the natural reserves in Mexico.
In this study area, three STPs located in the Hotel Zone of Cancun were investigated to derive implications through comparison with the experiences of Korea and thereby contribute to solving sewage management issues in Mexico. In the analysis of operational status, all three STPs were found to show some level of degradation due to aging. For the improvement plan, a maintenance and monitoring program to maintain facility operational efficiency at 100% is required. Also, a set of operational parameters for each treatment processes should be developed and provided to the operators as guidelines for cases of different operational scenarios, such as the rainy season.
To improve the efficiency of processing, technical suggestions were made for each treatment processes in terms of effluent water quality. For better discharge of water through absorption wells, a simple filtering system can be added after the disinfection process for excess Total Suspended Solids (TSS). The addition of an anoxic tank to couple the anoxic process with the aerobic bioreactor process was suggested for removing nitrogen, but this will also affect the Biochemical Oxygen Demand (BOD) or TSS removal rate. For the disinfection process, it is recommended to change the disinfection system from the injection of chlorine gas process to a UV system. For operational guidelines, the standardized operation/design parameters that the Korean government recommends for efficient STP operation were provided.
To comply with the strict effluent limits expected, facilities will demand the upgrade to their sludge systems using advanced treatment technology. In addition to facility upgrades, technical diagnosis of sewer networks and the sewer system in the area, including sewer lines, pipes and connections, were suggested using newly developed technical diagnosis
guidelines. The development of new technical diagnosis guidelines and an upgrade plan for the STPs should be discussed and developed by a working group, which must be formed for better sewage management in the area.
To secure sustainable sewage management capabilities for these three sewage plants in Cancun, the monitoring system and the operation and management need to be improved. In terms of sewage treatment monitoring, in Mexico, water quality measurements are performed two to twelve times per year. The water quality in the three sewage treatment plants in Cancun is measured daily by sewage operators and also every three months by an external laboratory accredited by the the Mexican Certification Entity (Entidad Mexicana de Acreditacion, EMA). On the other hand, in Korea, water quality is measured twelve times per year (once a month) only for small sewage treatment plants of less than 50 m3/day. As the treatment capacity increases, the number of water quality measurements increases, and sewage treatment plants of greater than 700 m3/day manage the water quality of the effluent through real-time measurement.
In terms of the efficient operation and management of sewage treatment facilities, it seems that there is a need for standardized evaluations and feedback systems for sewage treatment plants in Mexico. In Korea, according to the Sewerage Act, local governments conduct periodic guidance and inspection, and the central government (Ministry of Environment) evaluates the operational status of sewage treatment facilities every year. Both countries employ sewage operation managers with the basic expertise required in the sewage field. However, unlike Korea, in Mexico, it is difficult to figure out a statutory education program in Mexico to improve the skills and qualification of sewage treatment operators.
As a result of examining the current status of operations and management of the three sewage treatment plants in Mexico and comparing it with Korea, three proposals are presented as follows: 1) strengthen the monitoring system through real-time measurement of sewage effluent, 2) reinforce sewage management with a standardized evaluation and feedback system at the national or state level, and 3) provide mandatory education and training to strengthen the capabilities of operators. STPs are the primary point sources of pollutants discharged into public waters. Effluent limits are an enforceable regulatory mechanism, which is critical in point source control and water quality management. Since January 1, 2021, more stringent effluent limits have been implemented for the STPs located in the study area by reclassifying the receiving water bodies. However, it is thought that current effluent limits are not stringent enough to conserve the water quality and ecosystems in this region.
Development and strengthening of the regulations should proceed in stages, according to pre-arranged sewage policies and plans. Technical feasibility as well as water quality protection of the receiving waters should be considered in setting effluent limits. At the local level, it is advisable to apply more stringent limits to the large-scale STPs operated by FONATUR. As the three STPs account for a large proportion of sewage treatment capacity in the study area, stringent limitations can result in a significant reduction of pollutant discharge.
Institutional barriers would not be a key issue, as current sewage regulations in Mexico allow such selective application of stricter effluent limits to the STPs of concern. As FONATUR is considering an upgrade of the aged STPs, the application of stricter limits can be linked with the STP improvement projects. CONAGUA may look favorably on expanding the beneficiaries of the programs to federal agencies, provided that the federal agency’s project will significantly enhance the sewage treatment and that effluent limits stricter than the current regulations will be simultaneously applied to the newly constructed or renovated STPs. The development of a sewage policy strategy by the federal government and the
preparation of sewage maintenance master plans for each municipality is recommended, as such strategy and plans can facilitate the planning and implementation of sewage projects from a long-term perspective and in a systematic way.
At the national level, there is the Natural Protected Areas (NPAs) of Nichupte, named by CONANP as a ‘flora and wildlife protection area,’ and at the international level designated as a Ramsar site (wetlands of international relevance). Nevertheless, although these instruments recognize the relevance of the Nichupte system, the water itself is not directly included in the protection polygon. From the analysis of sewerage policies that apply to Mexican natural reserve areas, there is no specific sewage policy for the nature reserves in the study area.
Korea introduced an innovative water quality management policy in 1998 to improve water quality to a level suitable for drinking. Since it is impossible to improve and preserve water quality according to the general standards for the discharge of treated water, the TPLMS was introduced to manage the total amount of water pollutants. Because sewage is the largest source of water pollution, stricter standards for the discharge of treated water have been applied to manage the total amount of water pollution.
In considering the importance of Nichupte Lagoon for ecosystem conservation and the tourism industry, it is difficult to protect water quality and the ecosystem with the current standards of the effluent guidelines. Therefore, it is suggested that a TPLMS for water quality management be introduced for specific areas by referring to the case of Korea. In accordance with Article 89 of Mexico’s National Water Act, reinforced conditions could be introduced for the study area. The implementation of a TPLMS could be introduced by considering the local institutional capacity of the study area to calculate the total amount of load to protect the ecosystem and the measures to reduce the pollution load, including the treatment facilities and the restoration of mangrove forest ecosystems.
For the wastewater treatment facilities’ improvement plan, in the case of the expected strengthening of effluent standards due to the TPLMS, a separate project needs to be promoted including a management plan for water pollutants flowing into the Nichupte Lagoon and the improvement of sewage treatment facilities.