Wastewater Infrastructure Research Articles

Non-point source fecal contamination from aging wastewater infrastructure is a primary driver of antibiotic resistance in surface waters

Antibiotic resistance is a global threat to human health. Many surface water resources are environmental hotspots of antibiotic resistant gene (ARG) transfer, with agricultural runoff and human waste highlighted as common sources of ARGs to aquatic systems. Here we quantified fecal marker genes and ARGs in 992 stream water samples collected seasonally during a 5-year period from 115 sites across the Upper Oconee watershed (Georgia, USA), an area characterized by gradients of agricultural and urban development. Widespread fecal contamination was found from humans (48% of samples), ruminants (55%), and poultry (19%), and 73% of samples tested positive for at least one of the six targeted ARGs (ermB, tet(B), blaCTX-M-1, blaKPC, blaSHV, and qnrS). While ARGs were strongly correlated with human fecal markers, many highly contaminated samples were not associated with sewage outfalls, an expected source of fecal and ARG pollution. To determine sources of contamination, we synthesized ARG and fecal marker data with geospatial data on land use/land cover and wastewater infrastructure across the watershed. This novel analysis found strong correlations between ARGs and measures of sewer density, sewer length, and septic system age within sample watersheds, indicating non-point sources of fecal contamination from aging wastewater infrastructure can be critical disseminators of anthropogenic ARGs in the environment.

Deconstructing citizenship and the growth of Detroit's green renaissance

Detroit is in the midst of a contemporary urban renewal project that is being carried out through green gentrification. The displacement of residents is happening through the discursive and political management of the water system, which produces conditions that leave residents with few options for remaining in the city. In this article, I explore how resource management, particularly water and wastewater infrastructure, has been used to degrade the political efficacy of Black Detroit residents. Drawing from ethnographic fieldwork and discourse analysis of news articles and government reports, I argue that in recent years the city of Detroit has developed a wasting economy. This political-economic structure relies on the coupling of deconstructive and constructive processes that promote the withering of citizenship in order to make way for radical racial transformation in access to and control over the city. Keywords: Green gentrification, environmental racism, infrastructural violence, embodied metabolism

Leveraging water-wastewater data interdependencies to understand infrastructure systems’ behaviors during COVID-19 pandemic

Social distancing policies (SDPs) implemented worldwide in response to COVID-19 pandemic have led to spatiotemporal variations in water demand and wastewater flow, creating potential operational and service-related quality issues in water-sector infrastructure. Understanding water-demand variations is especially challenging in contexts with limited availability of smart meter infrastructure, hindering utilities' ability to respond in real time to identified system vulnerabilities. Leveraging water and wastewater infrastructures' interdependencies, this study proposes the use of high-granular wastewater-flow data as a proxy to understand both water and wastewater systems’ behaviors during active SDPs. Enabled by a random-effects model of wastewater flow in an urban metropolitan city in Texas, we explore the impacts of various SDPs (e.g., stay home-work safe, reopening phases) using daily flow data gathered between March 19, 2019, and December 31, 2020. Results indicate an increase in residential flow that offset a decrease in nonresidential flow, demonstrating a spatial redistribution of wastewater flow during the stay home-work safe period. Our results show that the three reopening phases had statistically significant relationships to wastewater flow. While this yielded only marginal net effects on overall wastewater flow, it serves as an indicator of behavioral changes in water demand at sub-system spatial scales given demand-flow interdependencies. Our assessment should enable utilities without smart meters in their water system to proactively target their operational response during pandemics, such as (1) monitoring wastewater-flow velocity to alleviate potential blockages in sewer pipes in case of decreased flows, and (2) closely investigating any consequential water-quality problems due to decreased demands.

Challenges, drivers, and benefits to integrated infrastructure management of water, wastewater, stormwater and transportation systems

Infrastructure systems are known to be interdependent systems; however, infrastructure systems are typically managed individually by agencies in charge of these systems. The existing literature has proposed the concept of an integrated infrastructure management approach, yet this literature has focused on managing infrastructure systems in short-term contexts (e.g., response to natural and human-made disasters). As such, limited understanding exists about implementing an integrated infrastructure management approach in the long-term (i.e., maintenance and rehabilitation). This study aims to explore the challenges, drivers, and benefits of implementing an integrated urban infrastructure management approach by agencies managing urban water, wastewater, stormwater, and transportation infrastructure systems in the long-term. This study qualitatively analyzed 15 semi-structured interviews with stakeholders in the management of infrastructure systems in Chile. It was found that the implementation of an integrated infrastructure management approach is challenged and driven by organizational instead of technical aspects. It was found that the local context where agencies operate represents a challenge for the successful implementation, the willingness to collaborate of infrastructure agencies’ workers represents a driver to implementation, and that benefits encompass agencies and users. Infrastructure agencies can use our findings to account for contextual conditions to successfully implement an integrated infrastructure management approach.

Sustainability assessment of strategic asset management decisions on municipal water infrastructure systems: Framework and application

AbstractDeveloping socially acceptable, environmentally friendly, and financially viable asset management plans (AMPs) is a major challenge for water and wastewater utilities and calls for a comprehensive Sustainability Assessment (SA). This paper proposes a novel framework that applies System Dynamics and Life Cycle Assessment tools to evaluate the long‐term sustainability of strategic asset management decisions for water and wastewater infrastructure systems. The merit of the proposed framework in dealing with the non‐linearity and dynamic behavior of the socio‐economic systems and its utility for SA of strategic asset management decisions are demonstrated in a case study of a Wastewater Collection (WWC) network system. Furthermore, the significant importance of population growth and urban densification policies in sustainability of AMP are highlighted by comparing four alternative scenarios of (1) 100% urban densification, (2) 0% urban densification, (3) 50% densification, and (4) no population growth in the case study. The results of the case study show that the greenhouse gas emission, operational and capital expenses, and bill burden of WWC and treatment services significantly reduce with urban densification.

Life Cycle Sustainability Assessment of Wastewater Systems under Applying Water Demand Management Policies

Sustainability assessment of urban water and wastewater infrastructures, especially when it comes to managing existing systems, is of paramount importance. Hence, this study presents a comprehensive approach to investigate the sustainability of a real wastewater system under different water demand management policies (WDMPs) in the operation and maintenance stage. In this regard, life cycle sustainability assessment (LCSA) is used through its three main pillars, which are (1) environment, (2) economy, and (3) society. Accordingly, (1) Environmental assessment is conducted using life cycle assessment (LCA) considering a thorough inventory dataset; (2) The economic assessment results are analyzed by the life cycle cost (LCC) method; and (3) Social life cycle assessment (SLCA) is conducted using the analytic hierarchy process (AHP) method, in which three main stakeholders “public and local community”, “workers and employees”, and “treated wastewater and sludge consumers” are considered. Finally, to prioritize scenarios, the results of LCA, LCC, and SLCA for every scenario are aggregated to account for the sustainability score using the AHP. The results of applying the proposed method to a real case study show that scenarios leading to less reduction in wastewater production are more sustainable options as they represent better performance regarding economic and social aspects. The proposed framework provides a better insight into the integrated sustainability analysis of urban water infrastructures. In addition, it can be used as a guideline for exploring the effects of WDMPs on wastewater systems in different study areas.

Antimicrobial Resistance Monitoring of Water Environments: A Framework for Standardized Methods and Quality Control.

Antimicrobial resistance (AMR) is a grand societal challenge with important dimensions in the water environment that contribute to its evolution and spread. Environmental monitoring could provide vital information for mitigating the spread of AMR; this includes assessing antibiotic resistance genes (ARGs) circulating among human populations, identifying key hotspots for evolution and dissemination of resistance, informing epidemiological and human health risk assessment models, and quantifying removal efficiencies by domestic wastewater infrastructure. However, standardized methods for monitoring AMR in the water environment will be vital to producing the comparable data sets needed to address such questions. Here we sought to establish scientific consensus on a framework for such standardization, evaluating the state of the science and practice of AMR monitoring of wastewater, recycled water, and surface water, through a literature review, survey, and workshop leveraging the expertise of academic, governmental, consulting, and water utility professionals.

Public-Private Partnership in the Context of Sustainable Development on the Example of the Water and Wastewater Sector

The purpose of this paper is to analyze the implementation of investments in the water and sewage sector in Poland and other European countries using the Public-Private Partnership (PPP) formula. The paper identifies the strengths and weaknesses, opportunities and threats arising from the use of this formula for local government public tasks for the delivery and treatment of domestic wastewater, in the context of EU legislation. It also examines the validity of the use of PPP in the context of the implementation of the principle of sustainable development in water management. PPPs are commonly used to deliver strategic public services under financial limitations. Countries such as the United Kingdom and Ireland, based on years of experience and good practices, are effectively implementing PPP projects, including those in the water and sewerage sector. The provision of treated drinking water and the treatment of municipal wastewater is a fundamental task ensuring an adequate quality of life for people by maintaining public health at an appropriate level. The fact that water and sanitation infrastructure and service provision in this sector is expensive, both at the construction and operational stages, has led countries at different levels of development to turn to public-private partnerships. Properly managed PPP projects secure the interests of both the private and public partner and the end user of the services. The analysis of data and examples of European PPPs in the water and wastewater sector shows that PPPs have been successful for most public entities that have chosen them. Good practices from Scotland, Ireland and Poland, as well as projects that have experienced difficulties, show that stable and friendly legislation, thorough pre-feasibility studies and an appropriate allocation of risk make PPPs successful. In the context of the conducted analysis, PPP is a tool enabling the realization of tasks in the water and sewage sector, where the public party’s budget possibilities are limited. Moreover, PPP is a component of the realization of the sustainable development principle. The idea that the use of natural resources, including water, which is fundamental to the biological and cultural needs of humankind, should be met in such a way as to save them for future generations, is realized in PPP projects. This paper demonstrates that the use of financial assembly opportunities in PPPs makes it possible to significantly intensify the construction of new and upgrading of existing water and wastewater infrastructure. It contributes to the protection of aquatic ecosystems and securing public health associated with living in direct proximity to surface water and discharging wastewater without affecting the natural environment and human habitats.

Wastewater System Inflow/Infiltration and Residential Pluvial Flood Damage Mitigation in Canada

Pluvial flooding in urban areas is one of the most significant drivers of disaster loss in Canada. Damages during pluvial flood events are associated with overwhelmed urban drainage (stormwater and wastewater) systems. During the period from 2013 to 2021, Canadian property and casualty insurers reported approximately CAD 2 billion in personal property (residential) pluvial sewer backup claims during flood catastrophes. There has been growing interest in managing pluvial urban flood risk, notably through newly funded national programs focused on climate change adaptation. These programs have included the development of new guidelines and standards focused on managing the underlying factors contributing to urban and basement flooding. Inflow and infiltration (I/I) has received limited attention in the pluvial flood literature, however. Informed by significant engagement with practitioners in Canada, this paper provides a review of the issue of I/I into wastewater systems and its relation to pluvial flooding. The paper will address concerns related to private property engagement in I/I and urban pluvial flood reduction programs. Both improved technical standards and administrative support are needed to ensure that wastewater infrastructure is less susceptible to I/I over its lifecycle.

Mapping the National Phosphorus Recovery Potential from Centralized Wastewater and Corn Ethanol Infrastructure.

Anthropogenic discharge of excess phosphorus (P) to water bodies and increasingly stringent discharge limits have fostered interest in quantifying opportunities for P recovery and reuse. To date, geospatial estimates of P recovery potential in the United States (US) have used human and livestock population data, which do not capture the engineering constraints of P removal from centralized water resource recovery facilities (WRRFs) and corn ethanol biorefineries where P is concentrated in coproduct animal feeds. Here, renewable P (rP) estimates from plant-wide process models were used to create a geospatial inventory of recovery potential for centralized WRRFs and biorefineries, revealing that individual corn ethanol biorefineries can generate on average 3 orders of magnitude more rP than WRRFs per site, and all corn ethanol biorefineries can generate nearly double the total rP of WRRFs across the US. The Midwestern states that make up the Corn Belt have the largest potential for P recovery and reuse from both corn biorefineries and WRRFs with a high degree of co-location with agricultural P consumption, indicating the untapped potential for a circular P economy in this globally significant grain-producing region.

Antimicrobial performance and biodeterioration mechanisms of alkali-activated slag

Eco-friendly antimicrobial alkali-activated slag (AAS) binders show great promise in newly designed and existing wastewater infrastructure threatened by microbial induced concrete corrosion (MICC). This work investigates the antimicrobial performance and biodegradation mechanisms of a new benzoate (BZ)-modified AAS binder. The bacterial activity, corrosion morphology, and material degradation mechanisms, of the novel BZ-modified antimicrobial AAS post-simulated MICC tests are analysed. The bacterial activity assessments (pH value, sulphate concentration, and live/dead staining) results demonstrate the remarkable antimicrobial efficacy of BZ-modified AAS in killing sulphur-oxidising bacteria A. thiooxidans and inhibiting biogenic acidification. The BZ-modified AAS demonstrates excellent microbial corrosion resistance with greatly suppressed production of deleterious gypsum and corrosion depth. The mechanisms of biodeterioration of antimicrobial AAS matrix are revealed, suggesting the nanoscale rupture of calcium-aluminosilicate-hydrate (C-A-S-H) in short chains and networking of aluminosilicate unites upon the removal of interlayer CaO polyhedral. The removal of Al-tetrahedra from bridging sites of C-A-S-H is more susceptible than that of Si-tetrahedra in AAS pastes under microbial corrosion. This study has demonstrated the potentials of novel antimicrobial AAS-based concrete as the next-generation construction materials for wastewater infrastructure.

Water footprints and sewage management challenges in second home tourism

While water consumption and water conservation have been issues in the discussion of sustainable tourism for many years, the residual part of the water cycle, the management of wastewater, lacks attention in tourism and planning research. This study addresses the wastewater challenges in Danish second home tourism. More than 200,000 second homes represent an important touristic resource both for owners and for short-term renters, and increasingly, the accommodation capacity is used over the whole year. Data from the building and housing register (BBR) show that only 54% of second homes are connected to public sewage and purification utilities. The remaining second homes rely on individual solutions such as septic tanks. A substantial regional variance can be partly explained by differences in the spatial layout and location of second homes, but mainly the dissimilar priorities in the responsible municipalities are the result of systemic factors following semi-privatized governance structures. The intensified use of second homes, rising ground water levels, more frequent climate incidences and EU and national quality obligations for the environmental standards of waterways and seas are and will in the future be challenges for the municipal wastewater management. A mobilization of second home owners and users to support updated wastewater infrastructures is hampered by the principles laid down in the governance structures.

A collaborative planning process to develop future scenarios for wastewater systems

Wastewater infrastructure has a long lifetime and is subject to changing conditions and demands. When plans are made to upgrade or build new infrastructure, transdisciplinary planning processes and a robust analysis of future conditions are needed to make sustainable choices. Here, we provide a stepwise collaborative planning process in which future scenarios are developed together with local stakeholders and expert groups. The process was implemented at one of the largest wastewater treatment plants (WWTPs) in Scandinavia. With a combination of workshops and the use of a web-based digital tool, future scenarios including flows, pollutant loads, and treatment requirements could be created. Furthermore, sustainability prioritizations affecting the WWTP, were identified. The future scenarios developed for the WWTP in the case study, predict stricter and new regulations, constant or lower future loads and ambiguous future flows. The highest ranked sustainability priority was low resource and energy consumption together with low CO2 footprint. The quantified future scenarios developed in the planning process were used as input to a process model to show the consequences they would have on the WWTP in the case study. Applying this collaborative process revealed future scenarios with many, sometimes conflicting, expectations on future WWTPs. It also highlighted needs for improvements of both the collection system and the WWTP.

Improvement of the Yangtze River’s Water Quality with Substantial Implementation of Wastewater Services Infrastructure Since 2013

Meeting the ever-growing demands of humans while ensuring sustainability is one of the great challenges of this century. China has made significant economic progress in recent decades and is increasingly engaged in international activities. This economic prosperity, however, has resulted in substantial contaminant discharge and damage to domestic aquatic ecosystems. Considerable efforts have been made to address these issues through developments in wastewater services infrastructure. Here, we provide an overview of wastewater infrastructure development in the Yangtze River Economic Zone during 2007–2017 and analyze diverse long-term monitoring data. These analyses trace and capture the key drivers affecting the restoration of water quality and determine how such restoration may be sustained or even accelerated in future. We find that there has been a decoupling trend between the economy and environmental variables since 2013, which coincides with the substantial implementation of improved wastewater treatment systems. While further developments in sewerage facilities and phosphorus discharge reduction may continue restoration, a paradigm shift toward a circular economy remains necessary to integrate these developments with wastewater resources management. Overall, this study advances the current understanding of the impact of wastewater services facilities on the balance between economic development and environmental protection.

Applying the sustainable system-of-systems framework: wastewater(s) in a rapidly urbanising South African settlement

Addressing wastewater infrastructure needs in urban informal settlements must simultaneously address legacies of past failures, current aspirations and constraints, as well as increasingly changing needs related to global environmental change. This study applied the Sustainable System-of-Systems framework for ergonomics and human factors to gain a better understanding of how small in-situ constructed wetlands could be a form of greywater treatment infrastructure in an informal settlement. Using 24 months of interviews, surveys, workshops and photo-ethnographic observations, we identified that the rapidly changing nature of parent (e.g. residency transience and land ownership) and sibling (e.g. housing and drinking water) systems put pressure on the target wetland system to adapt, often decreasing its capacity to deliver the service of water cleaning. Greywater treatment was not a common goal among stakeholders involved in the nested hierarchy system which likely contributed to the constructed wetlands needing to adapt to remain relevant. Practitioner summary: The value of the Sustainable Systems-of-Systems framework for ergonomics/human factors professionals in determining the sustainability of an ergonomics/human factors intervention is demonstrated using a greywater treatment system case study for an urban informal settlement. Understanding the variety of stakeholder goals and the pace of change in related systems was key to a sustainable intervention.

Downscaling reverse osmosis for single-household wastewater reuse: towards low-cost decentralised sanitation through a batch open-loop configuration

Abstract There is a significant demand for water recycling in low-income countries. However, wastewater infrastructure is primarily decentralised, necessitating the development of affordable household-scale reclamation technology. In this study, a batch open-loop reverse osmosis (RO) system is therefore investigated as a low-cost clean water reclamation route from highly saline concentrated blackwater. In a single-stage configuration, increasing feed pressure from 10 to 30 bars improved selective separation at water recovery exceeding 85%, whereas lower cross-flow velocity improved product recovery, reducing specific permeate energy demand from 21 to 4.8 kWh m−3. Rejection achieved for total phosphorous (99%), chemical oxygen demand (COD, 96%), and final pH (8.7) of the RO permeate was compliant with the ISO30500 reuse standard for discharge. However, the rejection of total nitrogen in the RO permeate was non-compliant with the reuse standard due to the transmission of low-molecular weight (MW) uncharged organic compounds. It is suggested that rejection may be improved by increasing feed pressure to rebalance selectivity but may also be controlled by reducing fluid residence time (storage) to constrain the hydrolysis of urea. The economic analysis identified that a high-pressure 1812 element cost of ∼US$30 meets the sanitation affordability index of US$0.05 capita−1 day−1. However, the unit cost of a high-pressure feed pump must be reduced to ∼US$500 to obtain an affordable system cost. These unit costs can be achieved by manufacturing 1812 elements at economies of scale, and by adopting pumping solutions that have been developed for other applications requiring high pressures and low flows. Overall, our findings suggest that RO in the batch open-loop configuration has the potential to deliver affordable and safe water production from blackwater in a decentralised (single-household) context.

Evaluation of fiber compositions, strength indicators, and disintegration patterns of flushable sanitary products in relevance to what is flushable

ABSTRACT Sanitary products (SPs) such as toilet paper and moist wipes are marketed as flushable products (FPs). SP manufacturers, wastewater authorities, and governmental agencies describe FPs in their own terms, and cause confusion about what is safe to flush with respect to sewer operations. To identify sewer-safe FPs, 11 toilet paper (TP) and 39 flushable wipe (FW) samples that were collected from around the world were examined to assess critical links between their fiber compositions, strength indicators, and disintegration performance. The findings illustrate that products that are made of primarily wood-pulp fibers have low strength, disintegrate rapidly, and are safe flushables. In contrast, products that contain strong and synthetic fibers (e.g. polyester) exhibit high strength, disintegrate slowly, and pose significant risk of accumulation in sewer systems. Suggestions are offered for product improvement and for long-term sustainability of FPs and wastewater infrastructures.

Water quality modelling and quantitative microbial risk assessment for uMsunduzi River in South Africa.

South African rivers generally receive waste from inadequate wastewater infrastructure, mines, and farming activities, among others. The uMsunduzi River in KwaZulu-Natal, South Africa, is among these recipients with recorded poor to very poor water quality. To identify parts of the uMsunduzi River that are polluted by Cryptosporidium and Escherichia coli (E. coli), this study mapped out pollutants emanating from point and non-point sources using the Soil and Water Assessment Tool (SWAT). Streamflow calibration in the upper and lower reaches of the catchment showed good performance with R2 of 0.64 and 0.58, respectively. SWAT water quality output data were combined with a Quantitative Microbial Risk Assessment (QMRA) to understand the microbial health implications for people using river water for drinking, recreational swimming, and non-competitive canoeing. QMRA results for Cryptosporidium and pathogenic E. coli showed that the probability of infection for most users exceeds the acceptable level for drinking and recreation as outlined in the South African water quality guidelines, and by the World Health Organization (WHO). The results of this study can be used as a baseline to assess the economic and health implications of different management plans, resulting in better-informed, cost-effective, and impactful decision-making.

Implementing wastewater monitoring on American Indian reservations to assess community health indicators

Healthcare access and health-related information for American Indian/Alaska Native (AIAN) communities is often limited. A potential solution to acquire additional population level health data is through wastewater-derived measurements, a method termed wastewater-based epidemiology (WBE), however, due to often remote locations with rudimentary wastewater infrastructure, the feasibility of implementing WBE on an AIAN reservation is unclear. In this study, we i) performed a preliminary assessment of percent connectivity of the top 10 most populous tribal reservations using available wastewater treatment facility information from the Environmental Protection Agency Enforcement and Compliance History Online database and satellite imagery, and ii) performed a sampling campaign on a select tribal reservation to measure common WBE indicators of health and behavior. Results indicate that, on average, approximately 81 ± 23% of tribal residents are connected to some form of aggregated wastewater collection system. On the sampled reservation, 6 communities comprising 7500 people were sampled across 160 km of reservation land using active samplers successfully deployed within the sewer network upstream of terminal lagoon systems. Results showed detectable levels of 7 opioids, 1 opioid maintenance medication, 5 stimulants, 1 hallucinogen, and chemical indicators of alcohol, nicotine, caffeine, and an over-the-counter cough suppressant. These results illustrated the feasibility in implementing WBE in rural and remote communities where information on community health may be lacking.

Persistence of Endogenous SARS-CoV-2 and Pepper Mild Mottle Virus RNA in Wastewater-Settled Solids.

Limited information is available on the decay rate of endogenous SARS-CoV-2 and pepper mild mottle virus (PMMoV) RNA in wastewater and primary settled solids, potentially limiting an understanding of how transit or holding times within wastewater infrastructure might impact RNA measurements and their relationship to community COVID-19 infections. In this study, primary settled solids samples were collected from two wastewater treatment plants in the San Francisco Bay Area. Samples were thoroughly mixed, aliquoted into subsamples, and stored at 4, 22, and 37 °C for 10 days. The concentrations of SARS-CoV-2 (N1 and N2 targets) and PMMoV RNA were measured using an RT-ddPCR. Limited decay (<1 log10 reduction) was observed in the detection of viral RNA targets at all temperature conditions, suggesting that SARS-CoV-2 and PMMoV RNA can be highly persistent in solids. First-order decay rate constants ranged from 0.011 to 0.098 day–1 for SARS-CoV-2 RNA and from 0.010 to 0.091 day–1 for PMMoV RNA depending on the temperature conditions. A slower decay was observed for SARS-CoV-2 RNA in primary settled solids compared to previously reported decay in wastewater influent. Further research is needed to understand if solid content and wastewater characteristics might influence the persistence of viral RNA targets.