WATER GLOBAL PRACTICE Water in Circular Economy and Resilience (WICER) The Case of São Paulo, Brazil Optimizing Wastewater Treatment Plants in the Metropolitan Area of São Paulo This case study is part of a series prepared by the World Bank’s Water Global Practice to highlight existing experiences in the water sector. The purpose of the series is to showcase one or more of the elements that can contribute toward a Water in Circular Economy and Resilience (WICER) system. This case focuses on the experience of São Paulo, Brazil. Context the region, many residents—especially in informal SABESP (Companhia de Saneamento Básico do Estado urban settlements—remain unconnected to the pub- de São Paulo S.A.) is the state owned water utility for lic network. In fact, the exceptionally high pollution São Paulo state. As such it is responsible for public levels in the urban tributaries of the Upper Tietê River water supply and sanitation services in more than 370 Basin are caused mainly by household sewage. On the cities, including 36 of the 39 municipalities that make one hand, CETESB (São Paulo’s environmental agency) up the Metropolitan Region of São Paulo (MRSP). In has been implementing monitoring-and-control pro- the MRSP, a vast urban swath of more than 21 million cedures to de-industrialize the Tietê River Basin since residents, public water supply has been practically the 1970s. But on the other hand, despite great efforts universalized. and investments to achieve de-industrialization, the river basin remains severely polluted. Not even the Under the Tietê River recovery project in SABESP’s con- peak rainy season can dilute wastewater in natura or cession area, the volume of wastewater collected for mitigate pollution flows from urban tributaries. treatment1 rose from 24 percent in 1992 to 78 percent in 2018.2 But despite São Paulo’s extensive efforts to Accordingly, using loans from the Inter-American improve and expand sanitation services throughout Development Bank and other resources from the 1 World Bank, SABESP has been expanding wastewater collection and treatment by 2033 (see the section on collection networks in the region’s poorest neigh- “Policy, institutional, and regulatory environment”). borhoods. Greater volumes of wastewater flows are SABESP therefore faces the urgent need to expand being directed to the main wastewater treatment its wastewater treatment capacity and improve the plants (WWTPs). Improved water quality can already quality of the effluents ultimately discharged into be detected in the Pinheiros and Tietê rivers and their the Upper Tietê. Most of the wastewater collected by tributaries., the Pinheiros River recovery program has SABESP in the MRSP is sent to five WWTPs, which overseen infrastructure upgrades in informal urban are also operated by SABESP (figure 1; table 1). It is settlements—improvements that have increased hard to find available land in the MRSP at affordable collection of sewage in the Pinheiros watershed for prices and at suitable locations for building treatment transfer to the Barueri WWTP. Also, in 2019, SABESP plants. The existing plants, originally conceived in the won the water supply and sanitation services con- 1970s, were therefore designed to allow future expan- cessions for three more municipalities in the MRSP, sion for receiving and treating increased volumes of including Guarulhos, a city of 1 million inhabitants wastewater. and deficient wastewater treatment. In addition to the ever-increasing need for services, SABESP has also Traditional solutions for expanding treatment capacity been handed the mission to universalize wastewater and improving efficiency in WWTPs WWTPs usually FIGURE 1. The Main WWTPs in São Paulo’s Metropolitan Region Sao Miguel WWTP Barueri WWTP Parque Nova Mundo WWTP Suzano WWTP ABC WWTP Legend Wastewater treatment plant ABC sewer system Barueri sewer system Parque novo mundo sewer system São miguel sewer system Sizano sewer system Minicipal boundaries Source: SABESP. 2 Water in Circular Economy and Resilience (WICER) TABLE 1.The MRSP’s Main Wastewater Treatment the need to invest in expanding facilities or in tertiary Plants (WWTPs): Nominal Capacity and Population treatment systems. Resources can be applied to other Served, 2019 purposes and achieve better outcomes, such as an Nominal capacity Nominal population expanded network for wastewater collection. WWTP (in m /s) 3 served (inhabitants) A joint initiative between SABESP and the 2030 Barueri 16.0 7,680,000 Water Resources Group (WRG), São Paulo, created ABC 3.0 1,400,000 an optimization program for the MRSP WWTPs. The Parque Novo Mundo 2.5 1,200,000 program defined high-priority actions and invest- São Miguel 1.5 720,000 ments to maximize the treatment capacity of existing Suzano 1.5 720,000 infrastructure. The program can be understood as a Total 24.5 11,720,000 circular economy program because it makes the most Source: SABESP. of resources, designs out waste and pollution, and regenerates natural systems. In particular, the program calls for building new civil infrastructure alongside aims to: existing facilities and installing tertiary treatment systems, such as ultrafiltering membranes or mem- • Maximize the use of materials and infrastructure already in place and increase assets’ efficiency and brane bioreactors. These solutions imply, however, life cycles by recovering damaged or inactive struc- high capital and operating expenditures—costs that tures and equipment and postponing the need for cannot always be justified in the face of other higher-­ further investments in expansion works or tertiary priority investment demands like expanding sewage treatment systems. collection in poor neighborhoods. To achieve the same ­ outcome, more innovative, efficient solutions had to • Reduce the generation of waste and pollution by be identified. improving both wastewater treatment processes and the quality of the final effluent. The program Solution: The MRSP WWTP Optimization will also allow SABESP to adopt a “from waste to Program resource” strategy and recover and reuse wastewa- ter treatment byproducts (water, energy, biosolids) International experience with WWTPs, along with in the future. greater operational efficiency, has shown that con- ventional (secondary) treatment processes can reach • Regenerate natural systems by improving the quality performance goals that exceed nominal design ­ of the effluent discharged into the Upper Tietê River. settings. Certain plant processes—such as primary ­ The purpose of the MRSP WWTP optimization pro- and secondary clarifiers and aeration tanks—have gram is to generate specific recommendations for treatment capacities that outperform nominal capac- ­ performance improvements in four plants operated ities foreseen by the original design. Sanitation util- by SABESP: Barueri, Parque Novo Mundo, São Miguel, ities often assume that the real capacity of all plant and ABC. One of the five main WWTPs operated by processes equals the nominal capacity. So, they tend SABESP, the Suzano plant, was not covered by the to expand an entire WWTP by “mirroring” the plant program because it already showed good performance without considering each plant’s actual capacity. This indicators. approach leads to overexpansion of infrastructure (and its subsequent depreciation). By way of contrast, opti- The methodology begins with data collection and analy- mizing conventional wastewater treatment postpones sis through “process auditing” at each treatment phase. Water in Circular Economy and Resilience (WICER) 3 The audits identify operational bottlenecks and offer efficiency goals that surpassed the nominal outcomes, technical recommendations to eliminate them. For or original design standards. It was also found that each of the four plants, the audit will specify the these actions  could be carried out with lower capital maximum potential treatment capacity in liters per expenditures and operational costs compared with second (L/s). And because current legislation requires other solutions defined in the company’s expansion 80 percent efficiency removal of biochemical oxygen plans—postponing or avoiding unnecessary costs. demand (BOD), the audits will recommend actions The impetus for this approach arose from early dis- (and investments) to improve effluent quality to reach cussions hosted by 2030 WRG. Leverage for the at 80 percent, 90  percent, and 95 percent efficiency project came from SABESP’s metropolitan board and removal of BOD—at current and projected flows for presidency, which understood the project’s strategic 2030. Total savings on operating expenses and invest- importance for the MSRP’s goal of reaching universal ments (capital expenditures delayed or canceled) are wastewater collection and treatment. In fact, SABESP calculated by comparing the investment needed for per- decided to expand the program to four treatment formance optimization with the traditional alternative plants, adding Barueri and the Parque Novo Mundo of expanding the WWTPs. Lowering operational costs to the two originally anticipated. The consultant pre- through power cogeneration with biogas in the WWTPs pared a new audit action plan and timeline to cover all will also be evaluated, along with investments in other four facilities and presented the specific equipment circular-economy interventions. With this knowledge, and human resources that SABESP would require for SABESP should be able to revise its expansion plans and the audit. Meanwhile, SABESP arranged to contract the invest in more cost-effective and sustainable solutions consultancy for the second phase (see below). to achieve the desired effluent quality at each plant. In summary, phase 1 included the program conception The Three Phases of the WWTP Optimization and structure; the optimization goals; mobilization Program of SABESP’s Metropolitan Wastewater Division teams Phase 1: Proof of Concept (March 2019 to April 2020) (management and operations); technical visits, work- shops, and meetings; the consultant’s preliminary In March 2019, 2030 WRG and SABESP Metropolitan analysis and recommendations on the two additional Wastewater Division held a round of workshops and treatment plants; and preparation for continuing the field visits. These analyzed the possibilities surround- program through a pilot application of the process ing circular-economy principles and technologies as audit methodology. they might apply to the MRSP treatment plants. 2030 WRG provided an international consultant, Daniel Phase 2: Audit Processes at Four WWTPs (May 2020 to Nolasco3, who has been working with the World Bank’s November 2021) Water Global Practice on the “From Waste to Resource” initiative. He supported SABESP workshops and field This second phase began on May 4, 2020, when SABESP visits. and ANDILET entered into an agreement. ANDILET is a private consulting firm, hired to conduct the process The preliminary findings from the phase-one work- audits of the four selected WWTPs.4 The following shops suggested that, in order to introduce circularity actions have been completed or are underway: into wastewater treatment systems, SABESP needs to prioritize investments that eliminate performance-­ • Analysis of historical performance data for each impairing operational bottlenecks. In this way, plant (sewage inflows, BOD levels, solid material each WWTP could achieve treatment capacity and removed, sludge production, etc.); 4 Water in Circular Economy and Resilience (WICER) • Installation and calibration of new online moni- • Effluent quality: BOD5 in mg/L and removal toring equipment at each plant to obtain data from percentages various locations inside the WWTPs; ­ • Screening and sand removal: material removed in • Field tests and laboratory analysis deemed neces- tonnes per month (t/month) sary to understand treatment capacity and quality parameters under stressed conditions; and • Sludge treatment and disposal cost: USD/t of treated and removed sludge (costs may rise as the quality • Discussions of hydraulic measures to address excep- of the effluents improves but may drop after the tional flows and protect plant operations. digesters’ heating systems are installed) At the end of this phase, ANDILET will deliver an • Demand and energy consumption: in kW and kWh optimization plan for each plant. The plans will iden- • Electricity cost: in USD/month tify bottlenecks and list recommendations. They will also include an analysis of potential capital expen- • Unit cost of electricity: USD/m 3 of treated wastewa- ditures delayed or canceled, investments needed, ter and USD/kg of BOD removed and the estimated operating expenditures required to reach each one of the BOD-removal performance The Policy, Institutional, and Regulatory scenarios described above (80 percent, 90 percent, or Environment 95 percent). SABESP did not foresee the WWTP optimization pro- gram for the MRSP in any previous plan, nor was it The information obtained through the audit tools responding to any specific new demands from a regula- should feed a dynamic model of each wastewater treat- tory institution. However, some aspects of São Paolo’s ment plant. Modeling should simulate the behavior of policy, institutional, and regulatory environment have the station operating at current and higher flow rates indirectly fostered this program. and confirm the treatment plant’s maximum treatment capacity; the BOD-removal performance scenarios for The first aspect concerns compliance with environ- the final effluents; the future generation of sludge; mental regulations. SABESP’s wastewater treatment demand for aeration (and electricity for blowers); bio- operations must comply with the statutory environ- gas production and the potential for energy cogen- mental standards on effluent discharge into water eration (heat and electricity); the most efficient and bodies and with the conditions set forth in each effective way to operate the WWTP; and the necessary plant’s environmental operating licenses. In the State expansion based on likely future demand. of São Paulo, conditions and standards for waste- water discharge are defined by art. 18, State Decree Phase 3: Implementation of the Audit Results No. 8468/1976, and later amendments. According to (Expected to Start in 2022) item V, the treated effluent must have a maximum BOD In phase 3, SABESP will incorporate the audit recom- of 60 mg/L), a threshold that can be exceeded only if mendations regarding the company’s investment plan the treatment guarantees a minimum BOD-removal to increase capacity and improve treatment of waste- efficiency of 80 percent. These requirements are water in the MRSP over the next years. As part of the stricter than those established at the federal level by process, key performance indicators (KPIs) will be CONAMA (The National Council of the Environment) monitored to measure the evolution of the efficiency Resolution No. 430/2011, art. 21, which requires a max- parameters and analyze the impact of implementing imum BOD of 120 mg/L and a minimum BOD-removal the audit findings. The indicators are: efficiency of 60 percent. As the stricter norm prevails Water in Circular Economy and Resilience (WICER) 5 in Brazilian jurisprudence, SABESP’s operations in the Phase 2 became viable through collaborative arrange- MRSP must comply with the requirements of the state ments among 2030 WRG, the World Bank’s Water legislation, as well as with the conditions defined in Global Practice, and SABESP’s metropolitan board. the environmental operating licenses of the WWTPs. The World Bank agreed that the concessionaire could São Paulo’s environmental agency—CETESB—is in invest resources, defined as its financing counterpart in charge of licensing, monitoring, and supervising the a loan agreement for investment in the SABESP Project compliance of SABESP’s operations. for Improving Water Service Access and Security in the Metropolitan Region of São Paulo. The second aspect relates to universalizing services. SABESP operates water and sanitation services in 36 Having confirmed these resources, SABESP hired a municipalities within the MRSP. It has a concession team of international specialists (ANDILET S.A.) to contract with each one of them. According to Brazil’s perform a complete audit of the four WWTPs men- new federal sanitation law (No. 14,026/2020, art. 11-B), tioned above for a fee that is less than 1% of the total new contracts for basic public sanitation services must investment needed to adequate the four plants to the achieve universal service by 2033. Specifically, 99 per- universalization goals. Signed on January 2, 2020, the cent of the population must have guaranteed water contract covers a period of 18 months. The final report, supply and 90 percent of the population must have with recommendations for optimizing performance guaranteed wastewater collection and treatment ser- in all four plants, should be delivered by November vices by December 31, 2033. The contracts also must 2021, a deadline that accounts for delays caused by the define quantitative goals for noninterruption of water pandemic. supply, loss reduction, and improvement of treatment processes. Ongoing contracts that did not define uni- Benefits versalization goals must comply by March 31, 2022. The program is designed to yield the following benefits: Thirdly, the competitive environment for sanitation concession contracts, established in the new federal • Improved water quality for the Tietê River: As legislation, has led to greater willingness to acceler- stricter scenarios for BOD removal are achieved ate investments in the efficiency of sewage treatment through optimized WWTPs—and as larger volumes systems. of wastewater are piped to the same plants—the MRSP expects significant improvements in the Last but not least, the regulatory implications of cer- water quality of the Tietê River, and downstream, tain ancillary gains (related to commercialization by 2030. of byproducts such as reusable water and biosolids) unforeseen by the concession contracts need to be • Investments delayed: As the WWTPs’ optimization addressed. Power cogeneration and direct nonpotable permits SABESP to postpone investments in tertiary reuse of treated effluents are also regulated activities treatment, and to reduce investments in physical that must meet statutory requirements. expansion of treatment phases, significant savings from delayed investments are expected. Financial and Contractual Agreement • More resilience through implementation of circu- Phase 1 of the program was financed by 2030 WRG, lar-economy principles: As SABESP expands capac- enabling the 2030 WRG consultant to conduct field ity, effluents can be sold as reusable, nonpotable visits and workshops, prepare preliminary technical water while improving service resilience in a region reports for discussion with SABESP teams, and define marked by water stress. The sludge treatment pro- strategies for the program’s continuation. cess also can cogenerate enough power to meet the 6 Water in Circular Economy and Resilience (WICER) operational needs of the WWTPs, thereby saving took action to correct operational issues at the energy. Biosolids and nutrients can be recovered treatment plant, based on recommendations facil- and sold. itated by the 2030 WRG consultant. From July to December 2019, SABESP invested B$  3 million in • Better protection against damage caused by climate the Barueri WWTP. In the first four months of 2020 change: As intense rainfall events are expected to SABESP installed new grating systems for solid rise, the program will help SABESP to enhance sta- removal, cleaned sand filters and aeration tanks, tions’ operations when facing abrupt, increased and implemented corrective maintenance proce- inflows during exceptional weather events. dures, avoiding discharges of 43,000 tons of BOD • Greater financial sustainability of the concession- in the Tietê River. But only the final audit will tell aire: As the recommendations for optimization and SABESP precisely what actions are needed to elimi- circular-economy investments are implemented, ­ nate bottlenecks to attain the full treatment capac- SABESP will reap financial benefits, as set forth ity and efficiency at each facility. above. At the same time, lower operating costs are expected from improved, more rigorous operation Lessons Learned and maintenance procedures. • The first step to develop a circular-economy pro- Although in the initial stages, the MRSP WWTP opti- gram for wastewater treatment plants is to opti- mization program has already produced concrete mize the operations of the infrastructure already outcomes: installed, so plants can reach maximum perfor- mance with the minimum capital and operational • Improved integration of SABESP’s internal depart- expenditure. ments: The development and implementation of the program has been carried out in a participatory • Optimizing the existing infrastructure should be manner, so that technical meetings, workshops, always considered before investing in new infra- and field visits involve management and operating structure to expand treatment capacity. The pro- teams and engineers from other SABESP areas. Each gram presented in this study updates the logic report was carefully discussed with the operation underlying traditional expansion strategies, focus- managers responsible for the treatment plants, as ing instead on priority actions and investments to well as with the engineering and project teams. This identify and eliminate bottlenecks and maximize dynamic has proved innovative, boosting interaction efficient treatment processes at each plant. and integrating areas and people that previously had been isolated within SABESP—an important cultural • Participatory, technical workshops are an effective way to engage stakeholders in the water and sani- change for the institution. tation utilities. Directors of units and operations • Increased technical knowledge: The workshops held teams have the opportunity to openly discuss tech- since the beginning of the program, in which consul- nical issues, learn and retain new knowledge, and tants have presented the technical analysis from the internalize best practices in current operations. audits, have built knowledge and motivation among SABESP teams responsible for wastewater manage- • Some aspects of the treatment process, during the project phase and during operations and mainte- ment in the MRSP. nance, must be adapted to the type and quality • Improved performance at the Barueri WWTP: of wastewater entering the stations, especially in During phase 1 and phase 2 of the program, SABESP regions where there are many informal households. Water in Circular Economy and Resilience (WICER) 7 • Discussions held throughout the program have Ellen MacArthur Foundation. 2015. Delivering the Circular Economy: A Toolkit for Policymakers. strengthened the notion that SABESP must expand European Commission. 2019. Circular Economy Action Plan: For a Cleaner its monitoring-and-control authority over sewage and Competitive Europe. networks in order to detect and minimize illegal NACWA (National Association of Clean Water Agencies), WERF (Water sewage discharges, preserving the biota of the treat- Environment Research Foundation), and WEF (Water Environment ment plants and the networks as assets. Federation). 2013. The Water Resources Utility of the Future: A Blueprint for Action. Alexandria, Virginia: Water Environment Federation. https://www​ • The methodology developed for this program can .wef.org/globalassets/assets-wef/direct-download-library/public/03--- be replicated for countless WWTPs in the state of resources/waterresourcesutilityofthefuture_blueprintforaction_final.pdf São Paulo and throughout the country. It should be Rodriguez, Diego J., Hector Alexander Serrano, Anna Delgado, Daniel Nolasco, and Gustavo Saltiel. 2020. From Waste to Resource: Shifting understood as a true innovation based on a com- Paradigms for Smarter Wastewater Interventions in Latin America and the prehensive and transformative vision for the man- Caribbean. Washington, DC: World Bank. agement of public fixed assets for basic sanitation, WEF (Water Environment Federation). 2016. Operation of Water Resource grounded in an analysis of efficient process engi- Recovery Facilities, 7th ed., Manual of Practice 11 (MOP-11). Water Environment Federation, Alexandria, Va. neering and focused on results. Water Environment Federation (WEF). 2018. Design of Water Resource • SABESP cannot clean up São Paulo’s rivers alone. Recovery Facilities. Manual of Practice 8 (MOP-8). Alexandria, Virginia: Besides the utility’s efforts in expanding wastewater Water Environment Federation. collection and treatment and improving treatment efficiency, the entire metropolitan region needs to Notes contribute to these tasks. Municipalities must take 1. Only the population living in SABESP’s concession area within the MRSP, which covered 33 municipalities in 2018, is reflected in this more effective control of land division and use, figure. The MRSP now consists of 39 municipalities. soil loss, discharges of untreated wastewater, and 2. The Tietê project consists of a large program of sanitation works solid waste disposal—tasks in which residents play aimed at improving wastewater collection and treatment services vital roles. These issues are beyond the scope of the and at cleaning up the Tietê River. It was launched in 1992. MRSP optimization program and in fact are beyond 3. Daniel Nolasco is a civil engineer from the University of Buenos Aires and has a specialization at Harvard and MIT, He has been working as the capabilities of any single sanitation utility. Other an international consultant in water and sanitation projects for over projects, such as the SABESP’s sustainable sanita- 25 years. He is also president of ANDILET S.A. and director of the tion program, which has received a World Bank loan, International Water Association (IWA). will be addressing some of these issues. 5 4. Some of the commonly used auditing tools are: review of historical data, flowmeter calibration, online monitoring, offline monitoring (laboratory analysis), jar tests, hydraulic modeling (for proper flow Background Documents division), oxygen transfer tests, tracer tests (in clarifiers and digest- ers), stress tests, studies of the return currents of the sludge train, Bonzanigo, Laura, Julie Rozenberg, Gregory Calner Felter, Robert J. and dynamic simulation (frequently using a BioWin simulator). Lempert, and Patrick Michael Reed. 2018. “Building the resilience of WSS utilities to climate change and other threats: A road map.” Working Paper 5. For more information, see: http://site.sabesp.com.br/site/interna​ 133227. World Bank, Washington, DC. /Default.aspx?secaoId=710. © 2021 International Bank for Reconstruction and Development / The World Bank. Some rights reserved. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of The World Bank, its Board of Executive Directors, or the governments they represent. The World Bank does not guarantee the accuracy of the data included in this work. This work is subject to a CC BY 3.0 IGO license (https://creativecommons.org/licenses /by/3.0/igo). The World Bank does not necessarily own each component of the content. It is your responsibility to determine whether permission is needed for reuse and to obtain permission from the copyright owner. If you have questions, email pubrights@worldbank.org.  SKU W21027