资源环境科技发展态势分析平台

Editor’s Note: Efficiently investing in wastewater and other sanitation infrastructure is crucial to achieve public health benefits, improve the environment, and enhance quality of life. Safely managed water, sanitation and hygiene (WASH) services are an essential part of preventing disease and protecting human health during infectious disease outbreaks, including the current COVID-19 pandemic. Learn more: www.worldbank.org/wastetoresource

Only 30 to 40 percent of the LAC’s collected wastewater undergoes treatment, a very low percentage given the region’s levels of income and urbanization, resulting in negative impacts on both human health and the environment. 

In the Metropolitan Region of São Paulo (MRSP), uncontrolled urban growth, irregular settlements, and untreated wastewater discharge continue to worsen the quality of water reservoirs and the security of water supply. While 95.6 percent of the state’s households are connected to the water supply network, 79 percent are connected to the sewerage network, of which only 62 percent is treated.

SABESP (São Paulo State Water Utility - Companhia de Saneamento Básico do Estado de São Paulo) collects and treats roughly 70 percent of the wastewater produced within the Guarapiranga Basin, which supplies water to a quarter of the MRSP’s population. SABESP manages a proactive program to reduce overflows, breakages, and leakages of the sewage system, along with cleanup programs of rivers within the basin. However, there is much to be done to ensure universal access to water and sanitation services and to clean up the water basin. Many informal settlements remain unserved and continue to contaminate the reservoir. The financial constraints faced by SABESP and municipalities have greatly reduced investments in the expansion and rehabilitation of sewage systems. In response, SABESP has prepared an ambitious plan to address these critical problems.

In December 2019, the World Bank signed with SABESP the SABESP Improving Water Service Access and Security in the Metropolitan Region of Sao Paulo Project to assist the water company in addressing these problems.  The project seeks to expand the provision of water and sanitation services for vulnerable people by reducing the direct discharge of sewage into water bodies upstream of the Guarapiranga reservoir and increasing reliability of the sewerage system – through the rehabilitation and modernization of sewerage networks, collectors, pumping stations, and connections to transport the water waste to the existing Barueri Wastewater Treatment Plant (WWTP).

In the Itapecerica da Serra municipality, a sewerage collection system will connect with a sewerage transfer pipeline that pumps wastewater from the Guarapiranga Water Basin to a treatment plant in a separate basin –benefitting 3,500 families. In the Embu municipality, the sewerage system would benefit 3,400 families, not to mention the downstream population, and includes 4.7km of main trunk pipelines that will also transfer wastewater to a treatment plant outside of the basin.

To further reduce the pollution loads reaching the Guarapiranga Reservoir, we are also working on promoting investment in innovative approaches to remove nutrients from the Embu Mirim River, which contains about 41 percent of the nutrient load currently released into the reservoir. A performance-based contract is being designed to engage the private sector in providing the most cost-effective solution for removing nutrients. This activity would also assist in accomplishing the maximum target of pollution load reaching the Guarapiranga Reservoir, as defined in the water quality law for the reservoir.

In 2019, aiming to introduce solutions to boost the circular economy, SABESP and 2030 Water Resources Group launched a project to optimize the existent wastewater treatment plant’s performance. Changes in the company’s auditing and management internal processes combined with targeted investments are already improving the quality of the treated effluents discharged into the iconic Tietê River, which crosses and degrades the metropolitan area.

The Ceará Rural Sustainable Development and Competitiveness Project (2012-2019) has contributed to the State’s efforts to ensure universal access to water services. Specifically, a pilot led by 15 families to reuse wastewater in their household (e.g. from the bath and kitchen) for irrigation helped these families increase the production yields of fruits, vegetables and legumes on their farms. This provided the families with readily available nutritious produce and diversified their diets. The excess produce was either sold or donated. The farmland itself benefitted from the re-used wastewater, as it lowered the pollution of soils and springs due to the significantly lower amounts of pathogens it contained. The project also financed water re-use knowledge exchanges for beneficiaries. 

In a circular economy, wastewater is and should be considered a valuable resource from which energy, nutrients and other resources can be recovered, as well as an additional source of water. Our work in Brazil provides an example of how wastewater – if treated and utilized more often – can lead to numerous benefits in human health and livelihood, the environment and the economy. Moreover, if implemented on a global scale, wastewater collection and treatment can serve as a key catalyst in helping more countries achieve universal access to clean water and sanitation, one of the SDGs. In times of increasing water scarcity, resources with untapped potential should not go to waste.