Inadequate wastewater management practices from small communities are becoming a serious contamination threat to the public health and water quality of the Gatuncillo Sub-watershed which belongs to the Panama Canal watershed. Gatuncillo is considered a high priority subwatershed due to its various water uses, such as public water supply, recreational activities, fishing, and operations of the Panama Canal. Typically wastewater systems consist of septic tanks and latrines with deficiencies in construction and design. The poor infrastructures combined with lack of maintenance and physical conditions (soil types and terrain) are causing wastewater from household systems to reach nearby streams, rivers, and yards.
A feasibility study for a wastewater management plan was conducted at the community of El Valle de La Union, as part of an overall integrated management and water quality program for the Gatuncillo Sub-Watershed. El Valle de La Union is a community of approximately 820 inhabitants and 180 houses, located in the Panama-Colon corridor. This community is considered a low-income, semi-urban community with a serious sanitation problem causing a potential public health risk and contamination of important water courses.
The primary goal of this feasibility study was to develop a sound and sustainable technical solution for the management of domestic wastewater generated by El Valle de La Union. The objectives were to evaluate the existing sanitation conditions of the study area; to evaluate and compare wastewater management alternatives; and to recommend an appropriate solution that will comply with wastewater regulations in Panama and will take consideration of the environmental, physical, and socioeconomic conditions of the community. Rapid appraisal methods (RAM), such as interviews with key stakeholders, direct observation, community workshops, and surveys, were conducted to gather information on the existing sanitation conditions, physical and environmental conditions of the area, community views and suggestions for improvements, and local and national government agencies views and responsibilities within the water and wastewater sector. The information gathered from the RAM was used in the selection and preliminary design of a technical solution, as well as informing and justifying the project to possible donors and national authorities.
The technical solution was selected based on a comparison process between wastewater management options and evaluation of treatment technologies. The wastewater management options were divided in two global alternatives:
- Individual systems (household) consisting of a septic tank with anaerobic filter followed by a shallow sand disposal field.
- Centralized systems consisting of 6,250 meters of sewerage and wastewater treatment. Four treatment technologies were evaluated for this global alternative: (1) septic tank with anaerobic filter followed by a shallow sand disposal field, (2) upflow anaerobic sludge blanket reactor followed by stabilization lagoons, (3) stabilization lagoons, and (4) activated sludge package plant.
Preliminary facility sizing and capital and operation and maintenance costs were developed for the individual system and for each of the centralized alternatives. A pair wise matrix using six parameters (implementation, reliability/performance, operability, capital cost, operations and maintenance (O&M) cost, and environmental impact) was used to compare the four treatment technologies of the centralized system.
Based on the comparative results of wastewater management and the evaluation of technologies, a centralized system with stabilization lagoon was recommended for the community of El Valle de La Union.
Non-technical recommendations that are critical for the sustainability of the project will be discussed in this paper. The recommendations relates to community participation programs, financial and economic study to determine willingness and capacity to pay of the users and tariff structure, and organization and capacity building of the community and stakeholders to participate in the construction and O&M of the wastewater program.
In addition, this paper will also address some of the challenges encountered in formulating a sustainable wastewater project for El Valle de La Union, such as meeting strict environmental regulations and weakness in the institutional framework for the operation, maintenance, and monitoring of wastewater systems.