Incremental Ecological Wastewater Treatment:
The Havana Prototype

Table of Contents

Introduction

Acknowledgements

Executive Summary

Local Context

Ecological Wastewater Overview

Ecological Treatment in Cantarrana

Concept Plan

Appendices

Bibliography

Industrial Waste It is not uncommon to see thick black smoke rolling from any number of smokestacks in the neighborhood. The beer and paper factories are among the largest point sources of water contamination in the Almendares. Because the factories in Cantarrana are state-owned, there is very little that can be done on a community level to control emissions. Due to their age, none of the factories in the neighborhood are affected by recent licensing and impact assessment requirements. However, because many residents work in these factories, there is public support to retain the industries and real incentive to improve, rather than do away with, the facilities. This has lead to efforts to reduce pollution on a case by case basis. Recently, the CO2 factory partnered with PMH engineer Marrero and achieved significant discharge reductions.
Wastewater Although industrial wastewater is more toxic than household wastewater, the latter still makes up the bulk of total effluent. According to a study conducted by the PMH, residential wastewater accounts for 70% of all waste dumped into the Almendares. Wastewater inputs include graywater (from sinks or cooking), blackwater (human waste), stormwater, and industrial and agricultural runoff. Average daily water usage in Havana is 225 liters per person per day (lppd). This is a citywide average that includes industrial, domestic, and other local services. Many leaks within the antiquated system result in loss of anywhere between 15- 40% of potable water. The average domestic use or disposal is 121-131 lppd. For Cantarrana, this figure is likely to be lower.
As described above, the neighborhood faces great environmental challenges from air pollution, industrial and domestic wastewater, solid waste, noise, and vibrations. Due to the proximity and severity of the environmental and health problems, local residents and factory representatives are well aware of the effects of air and water contamination on the vicinity. According to the nurse at the Cantarrana neighborhood clinic, air pollution is one of the biggest problems, causing large numbers of residents to suffer from respiratory problems. Water contamination spreads vector/fecal borne diseases such as dengue, cholera and malaria. Residents who live in houses unserved by sewage systems or in homes near the river and the creeks are most vulnerable. Solid waste collects along the river banks, aggravating the problem. Noise and vibrations from heavy truck traffic generated by the factories further diminish residents’ quality of life.
Open Space There is an estimated 9,500 m2 (based on field analysis) of open space along the Almendares and Santoyo which is mostly overgrown and appears to be largely unused in any formal sense. Vegetation along the river banks include fruiting trees, native and introduced plant species. The open space along the rivers is generally characterized by gradual slopes, but some steeper slopes exist along the Santoyo. While there is no apparent formal use of the open space, it is not uncommon to see pigs raised and trash accumulation within the area which further degrades its ecological integrity. Outfalls from residential and industrial sources leading to the river generally bisect the banks of the Almendares and Santoyo.	Open space map click to enlarge

Key Considerations

In order to plan any project, especially one that deals with human wastes, it is essential to have local and institutional support, physical land characteristics that are conducive to the project, and an economic climate that can support such an investment. Wastewater treatment, even when it is ecologically based, is traditiionally viewed as problematic by local communities and frequently rejected or subject to a great deal of mitigation requirements. This community opposition is not difficult to understand: wastewater treatment connotes ideas of odor, unsanitary conditions and negative visual impacts. Because of this, socio-political and cultural issues are equally important as technical or physical criteria when dealing with wastewater treatment facilities.

It is critical to address some very basic, broad questions in order to determine whether an ecological wastewater system is even feasible in the Cantarrana community. These questions are:

• Is there a need for wastewater treatment?
• Is it physically possible to locate and operate a system here?
• Will the community support this project?
• Will the system benefit the community?
• Are funding and resources available?
• Do feasible alternatives exist?

Cantarrana is well suited for localized, ecologically based wastewater treatment for a number of reasons. First, there is currently no wastewater treatment in the neighborhood, a deficiency which can have significant adverse impacts on the environment, human health, and the overall quality of life. Second, there is sufficient open space along the Almendares and Santoyo to site the project. Third, there is potential economic support from within and outside Cuba. Fourth, and most importantly, there is strong potential for neighborhood support, as illustrated during the public meeting. However, in order to generate continued support, it is essential that public education be integrated into the project, and that community residents have genuine input in the development of the project.

Furthermore, because this is a localized, community-oriented system, it is especially useful to look at opportunities and constraints from the perspective of Cantarrana residents themselves as indicated during the community meeting. One of their primary concerns was whether there is any real possibility of implementing alternative wastewater treatment in this neighborhood. The following analysis of opportunities and constraints is specifically intended to address that question.

Criteria Selection

The UW team’s initial report "An Ecological Wastewater Treatment Plant for Havana, Cuba" featured a list of important feasibility study criteria. Students drew these criteria from a selection of published engineering feasibility studies. The initial feasibility criteria focused on needed information for design decisions made much later in the process of system development (see Appendix 3. — Original Feasibility Criteria). The engineering feasibility criteria not only helped frame the site analysis, but also served as a framework for the discussion that follows. The following pages provide general answers without focusing heavily on specifics. However, the data presented is a useful base of information that the engineer or environmental expert can use as both a starting point and a guide for further investigations.

This study seeks to assess broader criteria. The perspective of a planner is that any project requires an approach that integrates economic, socio-political and physical criteria into the feasibility study process. A more focused look at the feasibility of an ecological wastewater treatment system within Cantarrana allows us to assess specific site conditions that could affect the selection and siting of an ecological wastewater treatment system. The criteria center around the following conditions: socio-political/cultural, physical (including environmental, community, infrastructure and health factors) and economic. These factors can enhance or hinder the feasibility of any project concerning wastewater treatment alternatives.

Socio-Political and Cultural Conditions

As suggested earlier, socio-political and cultural conditions are an integral factor when planning an ecological wastewater treatment system. Support from community, government and public or private institutions are necessary to plan, implement and maintain ecological wastewater systems. Furthermore, ecological systems must be in compliance with environmental regulations influencing water quality and infrastructure. Finally, cultural values, such as religious beliefs, can play a strong role in influencing public acceptance or denial of wastewater systems.

In Cantarrana, there are a variety of opportunities that can enhance the ultimate implementation of an ecological wastewater system (see Table 2). The community has expressed interest in the project, the PMH is interested in continuing the community involvement process, environmental regulation appears to pose no obstacles, and the PMH and GDIC have experience in fundraising and working with international NGOs. Constraints, however, include the following: the PMH or GDIC will have to embark on an active community organizing program, Cantarrana falls through the cracks between four governing municipalities, the PMH does not currently have clear authority to site such a project, and proposals for a conventional treatment system at Puentes Grandes might supercede an ecological, decentralized system.

Table 2: Socio-political and cultural opportunities and constraints

Physical Conditions

Appropriate physical conditions must exist in order to ensure a safe and functioning ecological wastewater treatment system. Environmental, community, existing wastewater infrastructure and health factors are key components to ecological wastewater systems. Site-specific community factors, including open space, land use, health impacts, and current waste management practices should have significant influence over the system selection.

Environmental Factors

Physical environmental characteristics, such as soil type and groundwater level are significant environmental factors influencing the selection of an appropriate land-based wastewater treatment system. The UW team achieved a basic understanding of the local soil structure and its relationship to the groundwater table underlying the Almendares watershed. In terms of a wastewater treatment system, it is imperative that system designers seek to minimize infiltration of untreated wastewater to the aquifer, due to its interchange with the municipal water supply.

Local soils (primarily clay underlain by limestone) are permeable, which argues for a system that results in minimal infiltration. It is crucial that experts test water and soil quality prior to construction and that they also monitor during operation. Such data is valuable in evaluating the success of the project and its feasibility for further implementation in other sites. Table 3 shows additional opportunities and constraints pertaining to environmental physical conditions within the PMH.

Table 3: Environmental opportunities and constraints

Community Factors

Cantarrana has ample open space, which is an asset in siting land-based ecological wastewater systems. Current agricultural uses would either be unaffected or even enhanced by implementation of the proposed system. As described in Section VIII, one of the benefits of the proposed system is the potential implementation of revenue-generating horticultural programs. The possibility of community opposition in the siting of this system, however, is still quite possible, so local input and involvement are essential during the planning process. See Table 4 for additional factors.

Table 4: Community opportunities and constraints

Wastewater Infrastructure Factors

The location of existing wastewater infrastructure, as well as the overall culture of water use in Cuba, are important factors in designing a locally appropriate system. Because wastewater infrastructure is currently lacking, it is easier to plan for and design a new, alternative system than to retrofit existing systems. In most cases, ecological wastewater systems are less expensive than conventional, which is an asset in a country with limited economic resources. Furthermore, Cubans use less water than citizens of most other countries. Future study should focus on key information such as influent levels and variation, flow and flood levels. Once these issues are quantified, it is possible to accurately design a site-specific system. Table 5 features additional factors that must be considered.

Table 5 : Wastewater infrastructure opportunities and constraints

Health Factors

One of the most significant impacts of a lack of wastewater treatment are its health impacts: many diseases are associated with water- and fecal borne contamination. The proposed system can reduce the risk of disease by improving overall water quality while the additional vegetation can improve ambient air quality. However, careful maintenance and operation of the system, as well as appropriate user behavior, is necessary to sustain the alternative wastewater system, which requires investments in job training and user education. Table 6 illustrates additional opportunities and constraints.

Economic Conditions

Finally, without adequate funding and technical support, an ecological wastewater treatment system will simply not be possible. This is especially problematic in Havana because of its overall economic conditions in the past decade. However, outside funding is certainly possible and not unprecedented; organizations such as the Canadian Urban Institute, UNDP/UNEP and OxFam have either participated or expressed interest in providing financial or technical support to infrastructure improvements in Cuba.

The proposed project can provide an additional benefit to local residents by creating jobs for construction and maintenance of the system, which is particularly important in light of the upcoming closing of local factories. However, availability of materials and local expertise is unknown at this point and must be analyzed locally. Furthermore, job training will be necessary, incurring an additional expense. More opportunities and constraints are listed in Table 7.

Table 7: Economic Opportunities and Constraints

Summary

The Cantarrana community has many opportunities for ecological wastewater treatment. Lack of existing infrastructure means that incrementally improved treatment is a feasible option. Ample open space along the waterways provides a potential site for ecological land-base wastewater systems. An overall lack of large-scale funding sources generates a need for low-cost systems. Given these opportunities and constraints, it is essential to develop an ecological wastewater system that will integrate the physical, socio-political and economic characteristics of Cantarrana. "Appendix 2. — Cantarrana Feasibility Tables" offers a more detailed analysis of the various factors that influence system planning and design.

As students of urban planning and landscape architecture, the study team defined the process and goals, and compiled basic information as a starting point for further studies. However, it must be acknowledged that many aspects of this project require further investigation by biologists or technical specialists. Before moving into the final design and engineering phases, project officials should conduct a more detailed assessment of the project’s technical feasibility. "Appendix 3. — Original Feasibility Criteria" contains a list of criteria which can serve as a guide for the further implementation of the plan.

The team has developed a proposal for siting the system and has chosen basic technologies and conceptual design ideas, but many details regarding levels of treatment, flow requirements and system construction will have to be finalized when more detailed information becomes available. The following section describes one potential ecological wastewater treatment scenario for Cantarrana.