Introduction

The city of Salvador, in the state of Bahia, Brazil, has a sanitary sewerage structure that serves more than 80% of its population by means of two ocean disposal systems, into which sewage treated by preliminary treatment stations is discharged. Until 1995, the city’s sanitary sewerage system had served only 26% of its population, concentrated in a few well-organized neighborhoods (Empresa Baiana de Águas e Saneamento [EMBASA], 2004). From that year on, an extensive program to expand the system was instituted, with the goal of cleaning up the Todos os Santos Bay, where the city is located. Conventional methods of construction, operation, and maintenance of sewerage systems generally require urban planning, which has not been done in the city of Salvador; at least 70% of occupation in the city is informal.

In the early 1990s, the state government of Bahia decided to raise financial resources to launch an environmental sanitation program, with the main objective of cleaning up the water in the Todos os Santos Bay (the second largest bay in the world) and improving general public health conditions in the city. This program included projects in water supply, sanitary sewage, solid waste, and institutional strengthening. The sanitary sewage and water supply components were done by the State of Bahia Water and Sanitation Company (EMBASA).

The condominial sewerage system is a methodology created in Brazil that combines technical changes in the design of collection systems along with a rigorous community participation component (Melo, 2008). In this model, the population is considered part of the solution. The main technical changes in the collection system are adaptation of the solution to the local reality, universalization of service, the use of the concept of microsystems (subbasins), and the use of the urban block as the basic collection unit.

Use of the condominial sewerage system made expansion of coverage possible, but challenges at the time and new challenges that have arisen since have had to be addressed using planning and interinstitutional coordination for integrated sanitation interventions in areas of existing urban construction where sewerage interventions have come in afterward, to guarantee universal coverage and the consequent improvement of the urban environment and residents’ quality of life, with the cleanup of the city’s rivers.

Salvador—General Description

The city of Salvador is located at the geographical coordinates 12º58'16'' south latitude and 38º30'39'' west longitude, with a total area of 706.8 km², including the maritime regions. Its mainland territory occupies an area of 300.0 km², bordering the municipalities of Lauro de Freitas and Simões Filho. Roughly triangular in shape, the territory of Salvador is surrounded by the sea to the south, east, and west, a factor that limits the possibilities for urban expansion. Well established in the southern portion of the triangle, the city grows northward, generating a chronologically decreasing urban fabric, in which the various economic cycles that have promoted expansion can be clearly seen (Prefeitura Municipal de Salvador, 2013).

The city of Salvador was founded by the Portuguese in 1549 on a cliff high above sea level, which, along with the existence of fortified gates, guaranteed the safety of its residents for many years, protected from the attacks from the French, Dutch, and indigenous populations. It is one of the first urban centers in Brazil and in colonial America, with around 3 million inhabitants, which places it among the largest capitals by population in the country. The city is one of the rare Brazilian cities that retains characteristics of the original historic site layout and was one of the first planned urban areas to be built on the American continent to be a colonial capital, a role it played until 1763 (Bahia, 2010).

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Figure 1. Aerial photos of the city of Salvador. The denser parts represent disorderly occupation and precarious urbanization.

Source: EMBASA. Reprinted with permission.

The rugged topography of the city, which has helped to defend its residents since the time it was founded, also accentuates difficulties associated with heavy rainfall and social inequalities that have never been solved, creating significant obstacles to the construction of sanitation infrastructure. Additionally, the unequal occupation of the city, with low-income residents building on slopes and valley bottoms and middle- and high-income residents on the ridges and oceanfront, has resulted in there being several “cities” within the city of Salvador, each with its own dynamics, leading to difficulties in the installation, operation, and maintenance of water supply and sanitary sewerage in Salvador. The city continues to expand in a disorganized process of urban land occupation, with both high- and low-income construction, making it difficult to universalize access to sanitation services (Figures 1 and 2). Such occupations, found across the city, which are constructed on drainage channels, rivers, and ponds, prevent the expansion of the sewerage system due to the impossibility of constructing sewerage networks and trunk collectors in these locations.

For the city to promote basic sanitation interventions compatible with other public and social policies, it must begin from the principle that sanitation is a collective goal, essential to human life and environmental protection, of public character that is an obligation of the state, which includes participation and social control in design, construction, monitoring, and evaluation (Santos et al., 2021). Federal law grants social control over sanitation to the people, which includes access to information, technical representations, and participation in the process of policymaking, planning, and evaluation of the provision of basic sanitation services. The challenge of universalizing access to basic sanitation for every citizen of Salvador implies the need for joint efforts and coordination between the three spheres of government: the municipality of Salvador, the state of Bahia, and the federal government.

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Figure 2. Aerial photo of the city of Salvador showing the informal city, with a precarious urban area and the formal, more organized part of the city. Respectively, the neighborhoods of Nordeste de Amaralina and Pituba, separated by the city park.

Source: Manu Dias/Bahia Photos. Reprinted with permission.

State of Bahia Water and Sanitation Company

Created on May 11, 1971, by State Law No. 2929, the State of Bahia Water and Sanitation Company (EMBASA) is a mixed-capital company with authorized capital, a private law legal entity whose majority shareholder is the state of Bahia, with 99.7% of the total capital. It is the state sanitation company that is responsible for providing water supply and sanitation services in 368 municipalities of the 417 that make up the state of Bahia. This represents the provision of 88% of the municipalities of the state with water supply and 25% of the municipalities with sanitary sewerage. The water supply coverage in the state, with a total population of 14,016,906 inhabitants, is 92% of the urban population, and the sanitary sewerage coverage is 46% of the urban population, which represents, respectively, 9,250,345 inhabitants and 4,605,710 inhabitants. To serve this population, EMBASA operates 453 water supply systems and 136 sewerage systems, with an annual turnover of 555.6 million dollars in 2020, and has 4,775 employees. Total water connections are 3,911,116 and sewerage connections are 1,426,031. The annual invoiced volume is 431,397,701 m³ of water and 208,136,896 m³ of sewerage (all data refer to the year 2020; EMBASA, 2021).

The Environmental Sanitation Program—Todos os Santos Bay

The sanitary sewerage system (SES) in Salvador was built in the 1970s, following guidelines established in 1968, in which the ocean disposal solution was planned. It was decided that the city’s sewage would be collected and pumped up to the district of Rio Vermelho, where the final disposal system would be located. The outfall began operation in 1972, and only some of the city’s basins were served by this system. With a capacity to carry 8.3 m³/s, it was used until the 1990s at only 5% of the capacity of the oceanic disposal system. In 1984, planning was revised and updated, confirming the selection of the ocean disposal system and planning for a second outfall. In 2003, the planning was updated again, with a projection for the new Jaguaribe outfall to meet the growing demand for sewerage in Salvador. In 1996, a broad program to expand the SES in Salvador was started.

The Environmental Sanitation Program of the Todos os Santos Bay (TSB) Program—also known as the Bahia Azul (Blue Bay) Program—had three interrelated objectives:

The total input of funds for the project was 600 million dollars, of which 264 million dollars were financed by the Inter-American Development Bank (IDB), 73 million dollars by the World Bank, 78 million dollars by the Japan Bank for International Cooperation, 69 million dollars by the National Social Development Bank (Banco Nacional de Desenvolvimento Social), 15 million dollars by the Federal Savings Bank (Caixa Econômica Federal) and a further 101 million dollars in resources from the state government (EMBASA, 2004).

To reach the objectives, work was done in the following areas:

As for the physical goals reached for the sewerage system, 2,071 km of collection pipes and trunk collectors, 116 km of interceptors and outfalls, and 86 pumping stations were built. Of the 187,916 household connections, 122,488 connections were made within the household (construction to connect internal sanitary installations to the household connections), and the flow capacity of the Rio Vermelho outfall’s preliminary treatment station increased from 5.5 to 8.3 m³/s (EMBASA, 2004).

The deadline for conclusion of the program was 5 years from the signature of the financing agreement with the IDB, which took place on March 1, 1996, but due to the complexity of the project and also because the value of the U.S. dollar increased a great deal during the period, which made more Reais available, there were three extensions. The program officially ended on June 1, 2004. The last IDB disbursement occurred on May 17, 2004.

During its implementation, the program encountered a reality that was not found in the textbooks or in the sewerage projects that had been developed until then: the disorderly occupation of the city, largely due to (a) the lack of discipline in the use and occupation of the land, (b) huge social inequalities, and (c) the absence of a housing policy to solve the housing problems of the low-income population, which led to the occupation of the city’s slopes, valley bottoms, stream banks, streams, and lagoons; an absence of defined street layouts; and a general lack of planned urbanization. To expand the sewerage system in Salvador, new techniques would have to be used since the conventional systems known until then could not be installed and the program would not reach its goal of 80% household coverage. To address this reality, the condominial sewerage system was used.

The Condominial System

The condominial system, which was created by the Brazilian engineer José Carlos Melo, is an innovative methodology that has been widely used to achieve universal sanitation coverage for very different urban social strata and all their topographic, urbanistic, social, and housing complexity (Melo, 2008). This model has been used since the 1980s in several Brazilian cities and progressively in other Latin American countries such as Paraguay, Bolivia, and Peru.

The condominial sanitation system offers a lower-cost technology (compared to the costs of conventional systems) for both sanitary sewage and drinking water supply. It is important to remember that this cost reduction does not mean that it is of lower quality, but installation does require care and attention to detail. It is simpler to construct because it uses small-diameter pipes laid at shallow depths and also because it adapts to all types of urban areas—areas of formal or informal occupancy, such as slums (favelas). This model promotes dialogue with local stakeholders, which results in broad participation at the political–institutional level, in civil society, at local sanitation companies, and, especially, with users (Melo, 2008).

This new service model is part of a technical innovation, which includes, in addition to engineering sewage collection and drinking water distribution systems, a social community participation component, which looks for suitable alternatives to be able to serve each household or family. These two components, strongly integrated, are what make the condominial model successful.

The design methodology offers a new configuration for effluent collection systems, which reduces the costs of effluent transport and treatment units by using the concept of decentralization, fostered by the strategy of using microsystems.

The microsystem is made up of the natural drainage basins or subbasins in the intervention area. This strategy allows each microsystem to be studied independently. As modules, they indicate the possible stages of the implementation process of the general system as a whole.

In practice, the condominial sanitation system considers the urban block (or what resembles a block, with a small group of buildings) to be the basic unit of the collection system. From the physical point of view, the sewerage system is responsible for collecting the sanitary effluents through pipes installed in the blocks, in the best possible layout, which is agreed upon with the residents. The pipes make household connections possible and are sized according to the existing demand on each block. The pipes should be located close to the lot, ensuring that they are built in areas of public domain—sidewalks, alleys, stairs, alleys, and so on. If it is not possible to lay pipes in these areas due to topography or the type of urban occupation, the most appropriate route should be used, even if it crosses private areas, which highlights the importance of community participation in the process of planning, implementation, and operation of the system (Melo, 2008).

Each urban block must have a connection point to the main collection network, which is called the basic network (rede básica) in the condominial model. This configuration streamlines the basic network: First, its length can be reduced (to about one third of the length of the conventional system), and second, it can be designed to have shallower depths (Figure 3).

Reduced lengths and shallower depths minimize interference with other urban infrastructure systems as well as problems due to the proximity to groundwater and the existence of rocks. The biggest expenses in the installation of a sanitary sewerage system are those related to laying pipes, excavation, and trench shoring, so the shallower and less extensive the system, the lower the construction costs will be.

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Figure 3. Model of the conventional sewerage network.

Source: Melo (2008). Reprinted with permission.

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Figure 4. Model of the condominial sewerage basic network.

Source: Melo (2008). Reprinted with permission.

In the condominial approach, the blocks are called condominiums (condomínios), and the sewage collection pipes are called condominial branches (ramais condominiais) (Figure 4).

The condominial branch line must serve all the households, even if they are in very unfavorable conditions. Therefore, the layout needs to be based on the actual conditions of the sanitary facilities in each household.

Based on the topographical characteristics of the block, as well as on the location of the building on the lot and, more important, the location of the sanitary facilities (the outlet of the last drain in the facility), the condominial branch line must be placed appropriately to ensure that the buildings are connected. The wastewater connections that originate in the buildings are connected to the condominial branches through simple inspection boxes.

There are four options for condominial branch placement: the sidewalk branch (Figure 5), the backyard branch (Figure 6), the front yard branch (Figure 7), and the branch that goes wherever it can go (Figure 8).

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Figure 5. Sidewalk branch model.

Source: Melo (2008). Reprinted with permission.

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Figure 6. Backyard branch model.

Source: Melo (2008). Reprinted with permission.

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Figure 7. Front yard branch model.

Source: Melo (2008). Reprinted with permission.

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Figure 8. Branch that goes wherever it can go.

Source: Melo (2008). Reprinted with permission.

One type of branch is not better than any of the others. The branch that will be chosen for a block should take the following factors into account: (a) It must be technically possible, (b) it must serve all households in an appropriate way, (c) it must allow the connection of the building facilities, and (d) it must be a decision made by the main stakeholders in the process, that is to say, the residents of the block.

Condominial technology creates a political understanding among the various institutional actors who work to implement it. Due to the greater simplicity of its physical systems, the most important parts of the system can be installed by various agents.

Political legitimacy is imperative from the very beginning. This process should be overseen from the highest levels of the water and sanitation sector and go through all the actors who could potentially be involved: states, municipalities, sanitation companies, the companies in charge of the project, consulting and construction, and, most important, beneficiary communities. Each actor contributes what is within their capabilities, and they all work within the parameters of the agreements established by the parties, with a goal of creating a strong contribution of new energies in favor of the solution (Melo, 2008).

Community participation is the foundation of the condominial sanitation system and the means to achieve political legitimacy; with all the neighbors participating in the proposals established by the model, the ideas and solutions result in service coverage for all users. The condominial model attempts to involve the community benefiting from the construction process through operation of the system and enables an intensive community mobilization process—a straightforward process that focuses on universal service provision and conscientious agreement, where social work must be an integral feature for the team responsible for the implementation of the condominial sanitation basic systems.

Once the decision has been made to use the condominial model, it is important that all the actors participate to establish the basic rules that guide negotiations, seeking agreement between all the agents involved in the new system—institutional operators, municipalities, private companies, and users. With this in mind, the responsibilities for financing, construction, and operation of the systems; the way they are administered; and the rates and tariffs to be used must be decided upon. Basic rules of adequate access are those that facilitate and promote the connection of condominial sanitation systems, as well as contribute to equitable and universal access, including the most disadvantaged portions of the population (Melo, 2008).

Community mobilization is done with the use of a set of coordinated actions where the main tool is the condominial meeting—which is held within each block. This condominial meeting is a time for participation, negotiation, decision, and development of community organization. In it, explanations and clarifications are made, and a collective debate about the system is developed, as well as the terms for operation and the rules for participation.

After these meetings, the process of behavior and attitude change begins. In these gatherings and in environmental and health education activities, the concept of coparticipation is presented, where the user has an active role in using water supply and sanitation systems appropriately and in making a commitment to environmental decontamination and becomes the main agent of change.

There is no unique formula for developing the mobilization process in the condominial sanitation project development methodology. Many strategies have been tried, but the following steps presented are considered the most appropriate, considering lessons learned from projects developed in several countries:

The Basic Engineering Project: This is developed through intensive field activities, which give the project a wealth of details and contain all the fundamental elements for the installation of the system. In the project, the basic network layout is decided upon, and the types of condominial branch lines are estimated based on the physical characteristics of the area occupied. This stage includes activities of a social nature aiming to involve the community from the beginning of the process.

Technical–Social Mobilization: This is the phase where community mobilization takes place. It must be done during all stages of the process and intensified in periods leading up to the construction work, generally during development of the executive project. Strongly integrated technical and social activities are developed to promote discussion about each condominium with the beneficiary population, to ensure that everyone agrees. Where condominial sewerage systems are used, the type of sewerage line to be installed in each condominium is decided upon with the community, and the general rules for access and use of the system are approved.

The Condominial Branch Executive Project: This is done during the construction work, which also leads to small adjustments being made in the basic network. The agency that is doing the work must decide on the most appropriate models that will be used to begin the community mobilization process, keeping in mind that the community should make the decision on the type of branch that will be used, to make beginning the construction work possible.

Looking at the methods presented, it can be concluded that the condominial model is in fact a technical–social system that paves the way to begin dialogue and triggers changes in behavior and attitudes toward sanitation services and the environment. It is developed at full scale, so that all the households are served, ensuring universal coverage.

Use of the Condominial System in the Bahia Azul Program

The Solution Proposed for Salvador—Bahia

The condominial method was proposed as a solution to make sewerage connections feasible in complex areas of informal occupation in the hills and valley bottom regions in the city of Salvador, Bahia, which represent somewhere around 70% of the urban fabric. With the installation of condominial systems between 1995 and 2004, as part of the sanitation program Bahia Azul, sanitary sewerage coverage went from 26% to approximately 60% in the city, reaching 80% in 2021 (EMBASA, 2021).

This solution was made possible by a political decision by the state government through the State of Bahia Water and Sanitation Company (EMBASA), to take on the enormous challenges of installing sewerage systems in informal settlements where conventional solutions simply could not be used. The fact that conventional models were not applicable in this urban context resulted in these populations being blocked from access to essential sanitation services. These communities were forced to find their own solutions, with the inevitable discharge of sewage into the rainwater drainage systems, resulting in degradation of health conditions for the residents of these neighborhoods and pollution of natural resources, compromising the water quality of the rivers and beaches in the city.

The sanitation program implemented in Salvador constitutes, together with the city of Brasília (the capital of Brazil), the biggest large-scale experience of the use of condominial systems in the world. The success obtained with the results of the project, with connectivity rates of 100% of the properties in the areas where it was implemented, made it feasible to expand the use of this model to other cities in the state of Bahia.

Since 1995, EMBASA has adopted the condominial system as the only service model in informal areas, serving a population of one and a half million people. This model has been used even in areas of formal occupation due to the significant reduction of installation costs and the simplification of operation and maintenance activities.

The Construction Process

Because the Bahia Azul program was so technically complex and had such a broad social and environmental scope, the state government created a dedicated institutional framework for planning, coordination, and construction of the program, involving several state governmental agencies involved in the areas of urban development, planning, water resources, environment, and sanitation. Construction of components related to sanitary sewage and water supply was under the responsibility of the State of Bahia Water and Sanitation Company.

The Basic Project

In the initial stages of program design, several technical studies were done, among them the revision and updating of Salvador’s sewerage master plan, as well as institutional studies on the expansion of the sanitation services offered in the city.

At this time, the basic engineering projects were also drafted to establish the main collection, transportation, and final destination structure of the new sanitary sewerage system. For the design of these projects, 21 sewage basins were identified to be served; these became the basic planning units for implementation of the program. Because this model is a technical–social methodology that works without changing engineering standards, it was not necessary to change the technical standards to be able to use the condominial system. The criteria and parameters established by Brazilian project norms for hydraulic sizing of the basic sewage network, such as the calculation of flows, diameters, slopes, tractive tension, and velocity, remained unchanged. The main change was the use of collective household connections (condominial branches [ramais condominiais]) in the substitution of individual connections to each house. Brazilian regulations do not determine the connection model to be used; this is a decision to be made by each operating company.

Once the boundaries of the drainage basins had been established, an initial design of the structure of what was considered the backbone of the system was done, made up of large interceptors and pumping stations. Collection systems were designed for each of the 21 sewage basins, composed of trunk collectors and collection networks, located where the road system allowed construction (Figure 9). For polygonal areas of informal occupation, quantitative estimates were made for the construction of the condominial systems, and the flow rates to be collected by the main structure were determined.

The process of raising financial resources for the rollout of the program was begun, based on plans for the basic projects and their respective budgets.

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Figure 9. Main interceptors and pumping stations of the Salvador sanitary sewerage system, with the two ocean disposal systems. The Jaguaribe outfall began operation in 2011. During the implementation of the Bahia Azul Program, all the sewage from the basins was sent to the Rio Vermelho outfall.

Source: EMBASA. Reprinted with permission.

Contracting the Construction Work

When the financial resources had been secured, the contracting process for construction of the main structure of the system (the backbone) as well as for the collection systems of the 21 drainage basins was begun. In the period from 1995 to 2004, 143 bids were made, and 317 contracts were signed for service delivery, construction, and provision of materials and supplies for the installation of the systems (Secretaria de Desenvolvimento Urbano do Governo do Estado da Bahia, 2006a, 2006b).

Because of the large number of interventions, and to meet the goals that had been set, a model was established that included the active participation of several state agencies and the State of Bahia Water and Sanitation Company, which included hiring several companies for development of the following activities: management and supervision of construction, drawing up executive projects, technical consultancy, and the actual construction work.

This model ensured a constant process of monitoring and supervision of work, considering that, to meet the ambitious targets set, the construction work was done at the same time in several drainage basins, each with distinct characteristics and with a great number of interventions.

Executive Projects

The executive projects were drawn up during the construction work by contracting consulting companies. These projects were submitted for approval by the State of Bahia Water and Sanitation Company’s technical teams and supplied to the construction companies to do the work.

Two groups of projects were established, depending on their specific characteristics. The first group included executive projects for the main structures of the collection systems (i.e., interceptors, trunk collectors, collection networks, pumping stations, and sewerage lines).

To design executive projects for the collection networks, the consulting companies used the following method, based on information in the basic projects: First they identified the several subbasins of the sewage basins, which were made up, in practice, of independent collection subsystems that could be built in parallel.

With this established through intensive fieldwork, the exact locations of the collection networks were decided upon, with identification of streets in the road system where the construction of these units was possible. At this time, the connection points of the future condominial branches to the collection system were also verified and decided upon, including establishing the locations of the devices needed (manholes) where the branches would connect. These projects were drawn with a high level of detail, especially in relation to interferences with the drainage system (natural or constructed) and the precarious existing collection systems built by the population to minimize problems with the temporary coexistence of the two systems (Figure 10).

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Figure 10. Final design of condominial branches.

Source: EMBASA. Reprinted with permission.

These studies resulted in the creation of several nonconventional elements to be able to integrate the collection systems into the complex conditions of urban occupancy. These included underground pumping stations under streets, pressurized segments (force mains) in the collection network, above-ground collectors, segments built with nondestructive methods, and wastewater capture from natural drainage channels during the dry season of the year that were designed to allow the temporary collection of effluents discharged by the population into the pluvial drainage system.

The second group of executive projects included those related to the design of the condominial branch (ramais condominiais) projects and was implemented in what was called a technical–social intervention project (Figure 11).

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Figure 11. Disorderly occupation in Salvador neighborhoods.

Source: EMBASA. Reprinted with permission.

The Technical and Social Intervention Project

The technical–social intervention project included the engineering and social activities required for installation of the condominial lines. Because of the close relationship between construction of the condominial network and the main collection system, the State of Bahia Water and Sanitation Company (EMBASA) adopted the solution of including executive project planning activities for the basic collection networks and the condominial networks, as well as the social mobilization activities, in the construction contracts made with the construction companies, under strict coordination and supervision by EMBASA’s technical teams. In this way, the construction companies were responsible for the creation of dedicated technical teams to develop these activities, made up of engineering professionals and social technicians, operating in a highly integrated manner.

The technical–social intervention projects were rolled out in stages, with a mix of engineering and social activities, highly synchronized and based on condominial methodology. Like the main collection system projects, the spatial unit for work development was the sewage subbasin.

The first stage of work consisted of activities to publicize the project and mobilize the various social actors around the intervention. This mobilization was done by holding large general meetings, called assemblies, to which the most important community leaders and organizations with close relationships with the population were invited. Among these key players were neighborhood associations, religious leaders, sports and cultural associations, schools, health clinics, representatives of local businesses, and representatives of agencies responsible for street cleaning and stormwater drainage.

In the general assemblies, various features of the sewerage system were presented and discussed, such as the general project design, principles of the condominial system, the project development process for the condominial branches on each block, the construction schedule and service stages, community participation in shaping the projects, and the relation between sanitation, health, and the environment, in addition to the general rules for access and use of the systems, such as the responsibilities of the public authority and of the population in regard to operation and maintenance, as well as issues related to payment of sewage tariffs.

After the general community mobilization process, the next step of executive project development for the condominial branches for each block was begun. Based on information from the cartographic foundation available, the first activity was to identify the physical limits of each block. Because of the peculiar characteristics of informally occupied areas, this activity was, by necessity, done in the field, with the goal of identifying a group of houses with a perimeter that separated one group from another with alleys, stairways, and lanes. The objective here was to define a group of properties that most closely resembled the concept of a formal urban block, considering urban occupancy and topographical characteristics.

Because of the dynamics of the process of occupation in informal areas, the cartographic foundations, which were created based on aerial images, were inevitably outdated; it was necessary to update them in the field, including new constructions and identifying the subdivisions between the buildings, which were invisible from an aerial image.

To that end, the technical engineering teams visited each block and each property to do this updating. At this time, the process of designing the project for the condominial branches was already under way. This process consisted of identifying the location of the sewage-generating points in each household (bathrooms and kitchens), discerning the current solution used by the residents, determining the depths of the pipes for internal installations and the spaces available for the installation of pipes, and pinpointing the best locations for the inspection boxes. Although this process was guided by criteria for an engineering project, the residents fully participated in the decision-making processes, which were done with the goal of reducing the impacts of the construction work, taking into account their plans for expanding housing units and, most important, the fact that branch pipes needed to be run from one lot to another until they reached their final connection point with the main network. In these cases, it was often necessary to understand neighborhood relations and negotiate the solutions to be used, attempting to transmit technical information to make the projects feasible.

Because these activities were not just focused on technical elements, the engineering teams were trained in social mobilization components, with the goal of conducting the abovementioned negotiation processes in such a way that the solution that was designed would be feasible from a technical point of view and sustainable from a social point of view, something that was necessary for the construction work to be done and for the subsequent operation and maintenance, especially in private areas.

The characteristics of physical occupation of the blocks in informally occupied areas, which included unplanned occupation, high density, and complex topography, meant that 95% of the condominial branches were designed as the “go wherever they can go” type. In this model, the pipe route formed a true labyrinth through the available spaces and inevitably ran from one lot into another.

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Figure 12. Typical circumstances for construction of the type of branch that “goes wherever it can go,” in which the lines are essentially built wherever possible.

Source: EMBASA. Reprinted with permission.

When the executive projects for the condominial branches were finished, the process of holding meetings with the residents of the blocks began. The meetings with the group of residents of each block were called condominial meetings.

In the condominial meetings, the projects that had been designed were presented and discussed, with the objective of confirming and/or adjusting the solution to be used. These meetings were held at night to ensure broader participation of all the residents on the block. The main topics covered were the discussion of the project, sanitary education on how to use the system, the responsibilities of each of the actors, rules for operation and maintenance, and information about the construction process.

At the end of the meeting, authorization for the construction of the branches was formalized. This authorization was made using a document called the “terms of agreement,” a sort of collective authorization, where the residents agreed to the construction of the lines in private areas, without the need for compensation, and decided on the operation and maintenance tariffs. To facilitate communication between EMBASA and the residents, during the meeting, a resident representative to the company was elected, called the “block manager” (sindco) of the condominium. The term “síndico” in Brazil is used to refer to the administrator of a formal condominium (such as a residential or commercial building).

During the period from 1995 to 2004, 7,373 condominial meetings were held, involving 144,618 connections and a population of 623,090 inhabitants. There were an average of 59 professionals on the teams of social workers involved in these activities. Part of the social team that was hired was made up of residents to facilitate the communication process and understanding of local social dynamics (EMBASA, 2004).

Branch Construction

Once the project design process and the negotiations with the population were completed, the branch (ramais) construction began (Figures 12–18). The criterion used to begin branch construction, aside from authorization from the residents, was the conclusion of the construction of the main collection system; because the interventions on the blocks often meant that the residents’ existing system would be deactivated, it was imperative that the new system begin operation immediately.

Another strategy that was used was to start with the blocks located in the higher areas of the subbasins to allow for the “cleanup” of the areas as the households were being connected to the new system, which produced very positive results in the process of mobilizing the population.

In the period between 1995 and 2004, 1,757 km of condominial branch lines were installed (EMBASA, 2004).

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Figure 13. Condominial network running between buildings and next to the stairway in a neighborhood of Salvador. The concrete covers of the inspection boxes are visible.

Source: EMBASA. Reprinted with permission.

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Figure 14. Condominial network running between properties with big differences in elevation between plots of land inside the blocks.

Source: EMBASA. Reprinted with permission.

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Figure 15. Condominial network in stairways and alleys.

Source: EMBASA. Reprinted with permission.

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Figure 16. Transporting materials for construction of branches in areas without vehicular access.

Source: EMBASA. Reprinted with permission.

Operation and Maintenance of the Branches

Before the community mobilization process began, the State of Bahia Water and Sanitation Company (EMBASA) established the rules that were to be used for the operation and maintenance of the systems. According to these rules, EMBASA was responsible for the operation of all units in the main collection system (i.e., interceptors, trunk sewers, basic networks, and pumping stations).

Regarding the operation of the condominial lines, two models for providing this service were established. For the first option, the residents would be responsible for these activities, and in that case, the monthly sewage tariff would be 40% of the monthly water tariff. For the second option, EMBASA was also responsible for the operation of the condominial branches, and the monthly fee was 80% of the monthly water fee.

These rules were presented during the condominial meetings, and the block residents decided which model would be used. The decision for the model had to be a consensus of the block residents, and individual decisions were not allowed because of the difficulties in managing this activity on the part of the company. The residents were informed that complex problems with blocked lines or those caused by problems with malfunction of the main networks would be resolved by EMBASA.

Before the implantation of the sewerage system, customers paid only a water fee. After the construction and connection to the new sewage system, the fee was increased to include a sewerage fee of 80% or 45% of the water fee. Almost all the blocks opted for taking on responsibility for operation and maintenance of the condominial branches, with a corresponding reduced sewerage fee of 45% of the monthly water fee, instead of 80%, the normal sewage fee. This increase was and remains an issue for users.

Because of the socioeconomic profile of the users and the need to ensure widespread agreement to use the new system by the public, which meant paying a monthly fee for the operation and maintenance of the systems, EMBASA adopted a strategy of waiving payment of the connection fee to the system. In other words, the costs of the construction of the condominial connections were fully assumed by EMBASA, unlike the practice adopted in other Brazilian cities, where these costs are charged to all users, regardless of their income level.

Household connections to the sanitary sewerage system were made compulsory by state law, enacted on January 23, 1998, under No. 7.307, regulated by State Decree No. 7.765, March 8, 2000. Once the network has been built and is functioning, EMBASA notifies the user, and the user has 90 days to connect their sanitary installations to the public network. In cases where elevation is necessary (the sanitary installations are below the level of the network), the user has 150 days to make the connection. After this period, EMBASA returns to verify that the connection has been made. Regardless of whether the user has made the connection, EMBASA is authorized by law to begin charging through its business system. The state environmental agency and the municipality are notified to compel the user to make the connection. The state regulatory agency for sanitation services (Agência estadual reguladora dos serviços de saneamento), together with the municipality, is responsible for enforcing the law.

The State of Sanitary Sewage in 2021 and Its Biggest Challenges

In 2021, the Salvador Sanitary Sewerage System (SES) was divided into 28 sewage subbasins with an approximate length of 4,300 km of lines and 937,644 households connected (EMBASA, 2021). The major expansion that took place in the system between 1995 and 2004 increased sanitary sewerage coverage in the city from 26% to 60% of the total number of households and allowed this number to continue to grow because the main SES interceptor and pumping station infrastructure was built at this time.

In 2021, coverage was at 81% and densification continued, with interventions being done more slowly because new connections now required interventions to improve existing urban development such as improving housing, macro and micro drainage, streets, paving, expropriations, and slope containment, among other things, which were not under the State of Bahia Water and Sanitation Company’s (EMBASA’s) jurisdiction and depended on interinstitutional arrangements between the Salvador city government, EMBASA, and the state government. Examples of these arrangements were in progress in 2021—for example, the Mané Dendê Creek basin project, in which the municipality was the executor, with EMBASA participating as an intervening party in the construction of the sanitary sewerage infrastructure and the Inter-American Development Bank as the financing agent for the interventions. A major urban and road improvement project was under way that would allow for construction of three trunk collectors, networks and branches that would serve the households in the basin, cleaning up the creek that forms a waterfall in São Bartolomeu Park, an important recreational structure for the city as well as for members of Afro-Brazilian religions.

Arrangements with the state as executor were also being led by the Urban Development Company of the State of Bahia (Companhia de Desenvolvimento Urbano do Estado da Bahia) in the city, using the same framework of first making urban improvements and then installing the sanitary sewerage infrastructure. The extensive social inequalities that have never been resolved and the lack of a housing policy for the low-income population, which is the majority of the city’s inhabitants, have led to the disorderly occupation of the city, with urban infrastructure being built afterward, when it happens at all. This situation makes it very difficult to make household sewerage connections because construction depends, above all else, on topography—as sewage is collected by gravity—and many times there is no technical way for the construction of networks and branches. The dynamic of occupation and expansion of homes negatively impacts the operation and maintenance of the sewerage system, as structures gradually occupy the spaces where the condominial networks run, in areas that residents have previously given permission for construction. In these cases, physical additions onto the houses are built where the condominial branches had been constructed in spaces that were previously empty.

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Figure 17. Houses that have been built on top of the condominial system network, making operation and maintenance difficult.

Source: EMBASA. Reprinted with permission.

The sections of the city in which disorderly urban occupation impeded construction of sewerage infrastructure were sorted into three main types: occupation of the banks of urban streams and rivers, occupation of the banks of urban ponds, and occupation on top of urban streams and rivers. They were called “Critical Sections,” identified in a report in 2006 (EMBASA, 2004), and those households continued releasing their sewage into the streams and rivers. This disorderly occupation also led to deficiencies in the provision of solid waste collection services, which are the responsibility of the city government, further degrading the water quality of urban rivers.

Two key solutions were implemented to mitigate these impacts: the use of condominial sewerage systems techniques where possible and the temporary construction of structures called “dry-weather catchments” until urban infrastructure was built, households were connected, and these catchments could be eliminated. The construction of these structures, which capture streams and even urban rivers and bring them to the sewerage system, generates problems for the system, such as the introduction of sand and garbage, which damage pipes and pumping equipment, as well as being major energy consumers, but they do keep the beaches safe for swimming when it does not rain. There was a program in progress to eliminate these catchments, but it always came up against situations in which it was necessary to make urban improvements before this could be done.

The construction, operation, and maintenance of the networks, branches, interceptors, and pumping stations of the SES are also impacted by the absence of a municipal plan for urban drainage: The sewerage networks are used by the population to drain rainwater, often by opening the covers of the system manholes and/or breaking the lines, allowing coarse solid waste and sand to enter the system, which causes clogging, overflows, and mixing of the sewage with rainwater, contaminating the streets, as the sewerage system does not have the capacity to drain these flows.

The system is an absolute separator system, designed to convey only sewage in its lines. Problems caused by external elements, linked to social issues, make the operation of Salvador’s SES even more difficult, such as vandalism (theft of materials, pipes, electric cables, pumps) and urban violence (there are areas of the city dominated by drug traffic, where access is limited or made difficult, requiring negotiations for teams to gain access).

Social workers from the units that are responsible for sewerage system operation negotiate with representatives of local residents’ associations to schedule the days and times for network and pumping station maintenance. These representatives indicate if and when it is possible for the teams to enter the sites. Usually, the resident representative is present during the work. When system expansion construction work is being done, it is often necessary to hire local resident representatives to avoid access problems.

Another complicating element is user nonpayment, a result of low-income levels and social inequalities, which EMBASA tries to mitigate with a separate tariff called a “social tariff.” Instituted by State Law No. 9.840/2005, participation requires users to have certain income characteristics and type of dwelling, with charges approximately half of the normal residential tariff.

In 2021, EMBASA did an assessment of each basin of the system, in which the coverage rates, operational problems, critical sections, and dry-weather catchments were surveyed, and the necessary actions and investments were estimated to reach 90% coverage of households by 2025 and 100% coverage in 2033, the base year of a new sanitation legal framework in Brazil.¹ The numbers were close to 900 million dollars and the program that will be created will require an interinstitutional arrangement between EMBASA, the Salvador city government, and the state government to be able to connect all the households and remove domestic sewage from urban rivers.

In 2023, a case study was being done in the Alto Pituaçu watershed, a pilot project in which the state of Bahia, EMBASA, and the municipality of Salvador were working together in an institutional agreement under the leadership of the state government to implement the urban projects and interventions needed to solve the problems in the critical sections and install sewerage infrastructure. The lessons learned were planned to be used in other basins, to help achieve universal access to the SES. It is of fundamental importance that the city government succeeds in regulating land use and, along with the state and federal governments, is able to create a housing policy for the low-income population, so as not to generate new disorderly occupations and new demands for urban improvements, making it possible to maintain citizens’ access to the system, improving their quality of life and the environmental quality of the city.

The condominial sewerage system, which began construction in 1995, continues to be successfully built, operated, and maintained in Salvador’s SES. The “social work,” which is done by a team of social workers, organizers, and engineers and includes mobilizing people in the community, holding meetings to discuss each party’s role in the design and construction of the condominial system, making agreements, discussing tariffs, and monitoring the construction work, is a fundamental part of the condominial system, as the population that will be served must be informed, educated, and encouraged to participate in the process of planning, designing, and constructing the system. As well as understanding the benefits of sewerage, people often need to understand how the system works to be able to agree to allow the lines to run through their homes, and this requires teams of social workers, along with technicians and engineers. During the Bahia Azul program, construction of the condominial systems included many teams of social workers, as an important structure, which participated in awareness raising, community meetings, and the election of block managers. After the systems went into operation, much of the social structure that had been in place during the construction of the Bahia Azul program from 1995 to 2004, such as the formation and maintenance of condominiums and their representative block administrators, was demobilized, so the social work teams during construction were larger than they are during operation. The sewage tariff initially offered to users, which was 45% of the cost of water consumption for those who had agreed to do the maintenance of their inspection boxes, was changed to the standard charge of 80% of water consumption once EMBASA definitively took over the maintenance of the SES.

The construction techniques and part of the social work, however, were continued, and practically all additions done to the system have used the condominial system, even in areas where the conventional system could have been used. In renovating Sete de Setembro Avenue in Salvador in 2022, probably the most important avenue in the city, which leads to the historical site where the city was founded, EMBASA used the condominial technique to replace lines and branches, which demonstrates how these techniques have been incorporated into the company’s daily routine. In EMBASA’s computerized maintenance control system, there is no longer a distinction between conventional and condominial systems, and the two forms coexist in Salvador’s sewage system.

Social work has continued with participatory meetings with residents on the streets where the condominial system is being installed, as well as door-to-door work communicating the availability of the network after it is ready. EMBASA has been doing pilot work to improve communication with the residents of neighborhoods, which are considered subnormal occupation (slums), to reduce failure to pay and to educate the public on how to use the sewerage system correctly. The ideal situation does not exist yet. Even though the system has been functioning for years, EMBASA is still learning and perfecting communication.

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Figure 18. Lines built practically in the sea due to occupation on the beach.

Source: EMBASA. Reprinted with permission.

While construction work for the expansion of the SES in Salvador was still being done, a study was contracted with the Institute of Collective Health at the Federal University of Bahia (Instituto de Saúde Coletiva da Universidade Federal da Bahia—UFBA) to evaluate the impacts of the program on the population. Children of various ages were monitored in several neighborhoods where the sewerage intervention took place, and compared with those where there was no intervention, the numbers were positive regarding an increase in quality of life of the population impacted by access to the service (Figure 19). Figure 19 shows data for children aged 0–3 years in neighborhoods where the sanitation intervention took place. In all of them, comparing 1997, when the program began, with 2003, when households were already connected, there is a reduction in the prevalence of enteric diseases (Universidade Federal da Bahia, 2018).

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Figure 19. Prevalence of Ascaris lumbricoides infections in preschoolers in Salvador basins who benefited from the Bahia Azul program.

Source: UFBA. Reprinted with permission.

The proven improvement in the quality of life of residents with access to sanitary sewerage systems should make universalization of access for households mandatory, eliminating a number of diseases that originate from the absence of sanitation and reducing public health expenses.

In 2020, the federal government approved and sanctioned federal Law No. 14.026, of July 15, 2020, which profoundly changed the basic sanitation legal framework (Law No. 11.445/2007), the Law of Public Consortia, Cooperation Agreement, and Associated Management of Public Services (Law no. 11.107/2005), among others. These changes brought new challenges for basic sanitation and particularly for public providers, as the law has presented a very challenging situation for the sector; it favors participation of private providers and hinders, if not prevents the implementation of sewerage infrastructure where it is most needed, and is less attractive to the private sector.

Not taken into account were the difficulties faced in construction and expansion in areas with social issues and in subnormal areas on the outskirts and in urban areas that have been occupied, large and medium cities, and coverage in rural communities; the absence of adequate public policies for urban planning, land use, and occupation; decent housing; integrated urban water management and water resource management and protection; preservation and recovery of the environment; and the lack of integration between these policies and basic sanitation public policy. The new law also established goals of 99% coverage of water supply services and 90% of sanitary sewage by December 31, 2033, which would be positive if there were an adequate financing policy to support the challenge set.

Land occupation by a public situated in distinct income brackets, as well as predatory economic activities whose main source of income is urban land, along with permissive regulation, has resulted in the disorderly occupation of valley areas and natural riverbeds, which has suppressed riparian vegetation, made the soil impermeable, and silted up the city’s bodies of water. Added to the rugged topography of the city, these factors have contributed additional difficulties for the installation and operation of basic sanitation services (Santos et al., 2010).

Lessons Learned

For such a massive slum sewerage coverage expansion program to succeed, some conditions were necessary. Among them, the most important are cited:

Conclusion

The installation of a sanitary sewerage program of the magnitude that was installed in Salvador beginning in 1995 and continuing to the present, with constant work by the State of Bahia Water and Sanitation Company (EMBASA) in slum areas, has not been an easy task. The success of the program was mainly due to the use of the condominial sewerage system, without which it would be impossible to install networks and connections in the households that occupy urban land informally; the existence of adequate financing; and a management structure capable of planning, designing, building, and then operating and maintaining the system. Community participation in these activities has been an essential requirement for the success of the program. Challenges have arisen where conditions of historical social inequality have not been resolved and new disorderly occupations have continued to appear every day, limiting the operation, maintenance, and expansion of the sewerage system. The use of reduced tariffs has helped, but it does not solve the problem of nonpayment, which hinders system operation. Associated with these issues, urban violence makes it difficult for operation and maintenance teams to access the system, promotes vandalism, and intimidates the population and EMBASA employees.

Despite all the problems that have been encountered, the sewerage system in Salvador continues to work with satisfactory efficiency, using the tools of the condominial system, which are continuously evolving as technicians and community interact, exchanging different but equally important knowledge. While the social issues of inequality, adequate housing, minimum income, and education, among others, have not been solved, EMBASA continues to install sanitation as an element that transforms the situation in the city, improving quality of life, with the goal of universalization of access. The success of this endeavor depends more and more on work that integrates the state, the municipality, and the company that provides the services.

The difficulties EMBASA has faced make it even more important to universalize citizen access to quality sanitation service, without exclusion, as part of a public strategy that integrates sanitation with health, environment, education, and urban improvements, among other things, which reduces social inequalities and moves toward improving quality of life. Appreciating the value of the condominial sanitation system, with intense community participation, will certainly be important on this path.