Cross-continental comparative experiences of wastewater surveillance and a vision for the 21st century.

The COVID-19 pandemic has brought the epidemiological value of monitoring wastewater into sharp focus. The challenges of implementing and optimising wastewater monitoring vary significantly from one region to another, often due to the array of different wastewater systems around the globe, as well as the availability of resources to undertake the required analyses (e.g. laboratory infrastructure and expertise). Here we reflect on the local and shared challenges of implementing a SARS-CoV-2 monitoring programme in two geographically and socio-economically distinct regions, São Paulo state (Brazil) and Wales (UK), focusing on design, laboratory methods and data analysis, and identifying potential guiding principles for wastewater surveillance fit for the 21st century. Our results highlight the historical nature of region-specific challenges to the implementation of wastewater surveillance, including previous experience of using wastewater surveillance, stakeholders involved, and nature of wastewater infrastructure. Building on those challenges, we then highlight what an ideal programme would look like if restrictions such as resource were not a constraint. Finally, we demonstrate the value of bringing multidisciplinary skills and international networks together for effective wastewater surveillance.

A framework for resource recovery from wastewater treatment plants in megacities of developing countries.

In developing countries, there is often a lack of a comprehensive data set that supports the development of coherent policies on resource recovery from wastewater treatment. This paper aims to contribute to the elaboration of resource recovery projects by providing accurate and updated data from wastewater treatment plants such as those located in the region of the Macrometropolis of Sao Paulo. The authors discuss possibilities of improvement of resource recovery for this illustrative example. Comprehensive analyses were performed based on data from 143 municipal wastewater treatment plants to understand the situation regarding resource recovery implementation in this region. The results show that just 26% of the plants perform at least one resource recovery practice. The predominant resource recovery practice is internal water reuse, and recovery is concentrated more in large plants than in medium and small ones. The sludge is disposed in landfills except for three plants, which perform sludge recycling for compost. Some plant managers reported interest in recovering energy from biogas, in expanding water reuse and in recovering sludge for fertilizer production or for building materials. Several aspects that have been regarded as relevant to the implementation of resource recovery processes in previous literature are discussed, such as the size of the plant, related legislation as well as treatment technologies and configurations. Finally, the authors propose a generic framework with several steps that can help to achieve resource recovery implementation. Therefore, the results can provide support for planning of resource recovery projects for large cities in developing countries.

Phosphorus recovery from municipal wastewater treatment: Critical review of challenges and opportunities for developing countries.

The aim of this paper is to provide guidance in selecting phosphorus recovery options within the municipal wastewater treatment sector regarding developing countries. This critical review includes a brief contextualization of the resource-oriented sanitation paradigm, the discussion of processes for phosphorus recovery based on methods at full-scale, pilot-scale and laboratory-scale, and a concise discussion of the environmental impacts and benefits associated with phosphorus recovery strategies. Finally, the main challenges related to the implementation of resource recovery strategies, especially for phosphorous, were identified and discussed. According to the results, some of the main drivers for phosphorus recovery are the limited availability of phosphorus, increasing cost of phosphate fertilizers and reduction of maintenance costs. Currently, most of the operational processes are based on crystallization or precipitation from the digester supernatant. Struvite is the most common recovered product. The recovery rate of phosphorus from the liquid phase is lower (10-60% from wastewater treatment plant influent), than from sludge (35-70%) and from sludge ashes (70-98%). Phosphorus recovery remains challenging, and some barriers identified were the integration between stakeholders and institutions, public policies and regulations as well as public acceptance and economic feasibility. In developing countries, the implementation of nutrient recovery systems is challenging, because the main concern is on the expansion of sanitation coverage. Resource recovery approaches can provide benefits beyond the wastewater treatment sector, not only improving the sustainability of wastewater treatment operations, but generating revenue for the utility provider.

Avaliação de um sistema de tratamento de águas cinzas em edificação de campus universitário / Evaluation of a greywater treatment system in a building of university campus

O reúso de água é um instrumento importante que contribui para a redução da pressão sobre os mananciais e para redução do consumo de água potável para fins que não requeiram água de padrão potável. Neste contexto, o presente estudo teve como objetivo principal analisar um sistema de coleta e tratamento de águas cinzas provenientes de pias de banheiro, chuveiros e máquina de lavar roupas tendo em vista o reúso não-potável em edificações. Os objetivos específicos foram: caracterizar qualitativamente e quantitativamente as frações de águas cinzas; operar e monitorar um sistema de tratamento de águas cinzas sintéticas em escala piloto e analisar o efluente após tratamento. A partir de uma edificação existente no campus da EACH/USP, adaptou-se a estrutura hidráulica de forma a permitir a segregação e coleta desta fração de águas residuárias para caracterização e tratamento. A instalação de hidrômetros nas tubulações de alimentação dos pontos de uso (máquina de lavar, chuveiros e lavatórios) possibilitou analisar a produção de águas cinzas individualizada. Para o tratamento em escala piloto, adotou-se um biorreator de leito móvel com biofilme (MBBR) seguido por decantador. A avaliação do sistema de tratamento foi realizada com base no monitoramento periódico dos parâmetros físico-químicos durante o período de operação do sistema. Com base nos resultados obtidos, dentre as três frações de águas cinzas, a do chuveiro foi a que apresentou maior concentração de E.coli...

Water reuse is an important tool that can contribute to the reduction of the pressures from human activities on water resources and to reduce the demand for potable water for purposes that do not require high quality water. Therefore, the main objective of this study was to evaluate a greywater collection and treatment system from lavatories, showers and washing machine aiming the non-potable reuse in buildings. The specific objectives were: to characterize in terms of quality and quantity the greywater from each source, to monitor a pilot system for synthetic greywater treatment and to analyze the quality of the effluent after treatment. In an existing building in the University of Sao Paulo campus, the wastewater collection drains were modified to allow the segregated wastewater collection and the greywater characterization and treatment. To evaluate the greywater generation three water flow meters were installed in water inlet of each greywater source (washing machine, showers and lavatories). The greywater treatment included a moving bed biofilm reactor (MBBR) and a settling tank at pilot scale. The evaluation of greywater treatment was conducted based on the periodic monitoring of several physicochemical water quality parameters during the operation of the experimental system. Based on the results, amongst the three greywater sources, the greywater from showers had the highest E. coli count while the lavatories greywater had the highest total coliforms count...