Wastewater Infrastructure Research Articles

Nontarget Analysis of Polluted Surface Waters in Bangladesh Using Open Science Workflows.

Nontarget mass spectrometry has great potential to reveal patterns of water contamination globally through community science, but few studies are conducted in low-income countries, nor with open-source workflows, and few datasets are FAIR (Findable, Accessible, Interoperable, Reusable). Water was collected from urban and rural rivers around Dhaka, Bangladesh, and analyzed by liquid chromatography high-resolution mass spectrometry in four ionization modes (electrospray ionization ±, atmospheric pressure chemical ionization ±) with data-independent MS2 acquisition. The acquisition strategy was complementary: 19,427 and 7365 features were unique to ESI and APCI, respectively. The complexity of water pollution was revealed by >26,000 unique molecular features resolved by MS-DIAL, among which >20,000 correlated with urban sources in Dhaka. A major wastewater treatment plant was not a dominant pollution source, consistent with major contributions from uncontrolled urban drainage, a result that encourages development of further wastewater infrastructures. Matching of deconvoluted MS2 spectra to public libraries resulted in 62 confident annotations (i.e., Level 1-2a) and allowed semiquantification of 42 analytes including pharmaceuticals, pesticides, and personal care products. In silico structure prediction for the top 100 unknown molecular features associated with an urban source allowed 15 additional chemicals of anthropogenic origin to be annotated (i.e., Level 3). The authentic MS2 spectra were uploaded to MassBank Europe, mass spectral data were openly shared on the MassIVE repository, a tool (i.e., MASST) that could be used for community science environmental surveillance was demonstrated, and current limitations were discussed.

A better cost:benefit analysis yields better and fairer results: EPA’s lead and copper rule revision

When conducted on a societal level, cost-benefit analysis (CBA) can indicate policies that best allocate scarce public resources. Done incompletely, CBA can produce spurious, biased results. To estimate the potential health benefits of EPA's recent Lead and Copper Drinking Water Rule Revision (LCRR), we used EPA's exposure, compliance, and effect coefficient estimates to monetize 16 of the health endpoints EPA has determined are causally related to lead exposure. In addition, we monetized one health endpoint that EPA has used elsewhere: preterm birth. We estimated that the total annual health benefits of the LCRR greatly exceed EPA's estimated annual costs: $9 billion vs $335 million (2016$). Our benefit estimates greatly exceed EPA's benefit estimates.There are also nonhealth benefits because lead generally contaminates drinking water through the corrosion of plumbing components that contain lead. The LCRR therefore has 2 components: reducing how corrosive the water is and limited replacement of lead pipes. Reducing corrosion damage to drinking water and wastewater infrastructure and residential appliances that use water yields significant annualized material benefits also: $2–8 billion (2016$). Effectively, the health benefits are free. Finally, while actual exposure data are limited, the available data on lead-contaminated drinking water exhibits known risk patterns, disproportionately burdening low-income and minority populations and women. This economic analysis demonstrates that to maximize national benefits and improve equity, the LCRR should be as rigorous as possible.

Age-dependent failure probabilities of corroding concrete sewer pipes under traffic loads

Concrete pipes are frequently used in the wastewater infrastructure. These buried structures are prone to ageing and deterioration, as well as damage under excessive stresses from traffic. This study presents the first set of temporal fragility models for underground concrete sewer pipes under the compounding effects of corrosion and truck loads. To address the high computational costs of fragility modeling, Bayesian Additive Regression Trees (BART) – a machine-learning based meta-model – are trained using a high-fidelity computational model of buried concrete pipes. The BART models are subsequently applied to develop age-dependent fragility models for serviceability and collapse of pipes conditional on truck loads. Considered uncertainties include statistically significant concrete and soil properties, truck load, and environmental factors that affect the corrosion of concrete sewer pipes. Results indicate that the direction of traffic stream, the degree of loss of wall thickness due to corrosion, and the maximum allowed truck load are critical factors that must be considered when planning inspection, rehabilitation, and retrofit of this underground infrastructure. According to the results, concrete sewer pipes buried in perpendicular to the direction of traffic flow are more vulnerable than those that are parallel to the direction of traffic flow. The results highlight that the probability of collapse is insignificant when it comes to vehicles weighing less than the design truck weight; however, the probability of collapse significantly increases for the moderate and severe corroded sewer pipes when it comes to the overweight vehicles. The age-dependent fragility models indicate that for sewer pipes buried perpendicular to the direction of traffic stream with service life of less than 25 years, the probability of the first major structural defect is less than 5%. This is also true for sewer pipes that have been in service for less than 45 years if the traffic stream is parallel to the buried pipe. The developed fragility models also constitute a key component of quantitative risk assessment of underground wastewater collection systems.

Using in situ measurements of optical brighteners for rapid reconnaissance of wastewater inputs to water resources

Untreated wastewater entering the environment through leaking infrastructure and sewer overflows threatens both human and aquatic health. Water managers therefore need low cost, in situ methods to detect sewage contamination in real time to promptly employ mitigation strategies. However, wastewater has traditionally been identified in waterbodies using chemical and microbial tracers and indicators that can be non-unique to wastewater and often require complex and expensive analyses. Optical brighteners (synthetic brightening compounds present in laundry detergents and paper products) are emerging as ideal tracers of wastewater because of their quick and inexpensive field detection using handheld fluorometers. To test the efficacy of optical brighteners as standalone, in situ wastewater tracers, field readings of their fluorescence were compared with traditional wastewater analytes (e.g., B, F−, microbial indicators) at multiple points in time and space for a suburban watershed (Fishpot Creek, Saint Louis, Missouri, United States). We also used chemical tracers in three mixing models of endmembers to assess the wastewater fraction across the watershed. Compared to other analytes, optical brightener fluorescence measurements had the strongest correlation with wastewater infrastructure density (r = 0.71, p < 0.05), indicating their utility as tracers. All our endmember mixing models employing optical brightener readings predicted positive and significant correlations between the untreated wastewater fraction in streamflow and sewer pipe density at each site (r ≥ 0.77, p < 0.05). While using optical brightener readings for wastewater detection has some limitations (e.g., minor photodegradation), we found them to be more robust tracers than other analytes. Thus, optical brightener fluorescence measurements are an ideal initial screening tool for identifying wastewater contributions to the environment.

Synergetic Water Demand and Sustainable Supply Strategies in GCC Countries: Data-driven Recommendations

The Gulf Cooperation Council (GCC) countries, characterized with limited water resources and high oil/gas revenues, rely heavily on energy-intensive seawater desalination and non-renewable groundwater abstraction. The need to shift solutions to demand-side practices and sustainable supply alternatives has been long advocated; yet this study is the first to “quantify” the impacts of such solutions on the water management system of Qatar – considered a study case of GCC countries. In this research, a scenario-based approach was utilized to predict the impact of water demand control and wastewater reuse (and the resulting synergies) on consumption of desalinated water, extraction of groundwater resources, and development needs of water and wastewater infrastructure. To this effect, country-specific models for Qatar were developed to project annual household water demand, wastewater generation and residential construction growth, up to year 2050. The outcomes showed that tariff reforms and regulated greywater reuse would reduce the annual household demand for desalinated water by up to 27% and 7%, respectively. Also, intensive reuse of Treated Sewage Effluent (TSE) would reduce 40–80% of total groundwater abstraction for irrigation by 2050. Finally, adopting an integrated water strategy, with combined demand and supply management targets, creates synergies that would: (1) limit groundwater abstraction to rates close to the aquifers safe yield; and (2) delay the need for expansion of the water and wastewater infrastructure by more than a decade. Data-driven recommendations were provided accordingly.

Intelligent sewage discharge control in a wastewater treatment plant during rainfall periods

ABSTRACT Uncontrolled wastewater discharges have social and environmental consequences and generate increased operational costs. Wastewater treatment plants (WWTPs) are vulnerable infrastructure and require the implementation of risk and safety analyses in the context of climate change and flooding. Therefore, making decisions in changing weather conditions is one of the most important but also most difficult tasks for operators to maintain proper management of wastewater infrastructure facilities. The aim of the research was to develop a decision-making tool based on soft sensor methods to allow inflows to be classified into two classes of WTTP operating conditions. The quality of the regression models was maintained at 90.0%, while the classifier based on the coarse decision tree had a testing accuracy of 92.4%. The results can contribute to a reduction in wastewater load, which is significant in the context of ongoing climate change, and to an improvement in WWTP operation through automation.

Beyond the Pipes: How User Perceptions Influence Their Water and Wastewater Infrastructure Interactions in Texas Colonias

Beyond the Pipes: How User Perceptions Influence Their Water and Wastewater Infrastructure Interactions in Texas Colonias

Assessing relationships between onsite wastewater treatment system maintenance patterns and system-level variables

Globally, millions of households rely on onsite wastewater treatment systems (OWTSs), such as septic systems, to safely treat and dispose of wastewater. Conventional subsurface OWTSs are a common and affordable option for many landowners, and effectively remove pathogenic and nutrient pollution from wastewater when properly sited and maintained. However, OWTSs can also be a source of nonpoint pollution in watersheds when they are not functioning properly. To better understand the drivers of OWTS maintenance and failure, we explored relationships between OWTS age, environmental characteristics (edaphic conditions, topographic wetness index, and distance to stream), and repair and pumping records for OWTSs in Athens-Clarke County, Georgia, USA. Repair records indicated that 7.8 % of the 8826 OWTSs in the study were repaired over a 78-year period and that the median age of a repaired OWTSs was 65 years old. Pumping records showed that 12.2 % of the OWTSs were pumped in a 38-month period (an annualized rate of 5.7 %). The suite of widely available environmental variables we used as predictors were likely not granular enough to detect patterns of individual system maintenance at this scale. However, we found that the oldest OWTSs (>50 years) had the highest probabilities of being repaired and exhibiting signs of hydraulic failure. Notably, new OWTSs (2–10 years) were nearly as likely as the oldest systems to exhibit signs of hydraulic failure. These findings suggest that repair and replacement efforts should target older systems that are at or near the end of their serviceable life, and, in addition to continually monitoring older systems, all OWTSs should be inspected one year after installation. By leveraging data that may already exist, practitioners in other localities can use this reproducible approach to estimate the performance of OWTSs. Our data and methods will support efforts to prioritize wastewater infrastructure investments and policies.

Assessing the impact of wastewater infrastructure along the Texas-Mexico Border: Did we make a difference on contagious diseases?

Municipal infrastructure is typically implemented to address a social need, yet not regularly evaluated to assess its impacts. This research explores the question of measuring the impact of wastewater infrastructure on water-borne diseases using the case study of Texas. There are over 300,000 mostly Hispanic residents living in informal settlements called colonias primarily located along the Texas-Mexico border. Until the late 2000′s these residents were using contaminated wells, hauled water, cesspools, or nonfunctioning septic tanks. Consequently, the incidences of contagious diseases associated with poor water quality greatly surpassed the state average. Federal and state agencies invested about $1 billion for first-time water and wastewater service in these rural communities with the objective of reducing water-borne diseases. This study applies a two-way fixed effects regression model to evaluate results using data gathered from publicly available reports and over 90 interviews with water and wastewater service providers. This quasi-experimental analysis exploited the size, location, and timing of wastewater infrastructure. Results show that residents in the eight counties with the largest colonia population experienced a 24% reduction in hepatitis A incidence rate. However, tuberculosis and salmonellosis rates do not seem to be affected by infrastructure investment and continue to be a problem. Most of the utility managers interviewed, especially in the more rural areas, coincided that even though population growth or economic development did not occur, they witnessed quality-of-life improvements. This research design and results contribute to an emerging body of literature on monitoring and evaluation of programs related to municipal infrastructure.

Optimizing Scale for Decentralized Wastewater Treatment: A Tool to Address Failing Wastewater Infrastructure in the United States

Wastewater systems (sewered or on-site septic tanks) are failing across the U.S. Economically disadvantaged populations, communities of color, tribal lands, and rural/peri-urban areas are especially vulnerable. Efficient deployment of public and private capital to assure appropriate service levels and affordability is a critical need. We present a modeling framework to identify economically optimal wastewater network layout and component sizes. Six system configurations are considered, which include gravity versus pressurized collection system flow and treatment of septic effluent versus raw wastewater. A case study for Uniontown, Alabama─a community that has been in national news for the failure of their wastewater infrastructure─is presented. We find that a decentralized network that separates and stores solids on-site, prior to conveyance to a cluster-scale treatment site, has a fraction of the capital and operating cost of a centralized system that is currently proposed. Broader implications are discussed.

The (in)visibility of sewage management and problematization as strategy for public awareness

Sewage management is crucial to the functioning of cities, yet, in the global North, seldom acknowledged in public. Wastewater infrastructures are mainly hidden underground and human excrement is considered a private matter. However, to make sanitation stay invisible, its dysfunctionality (e.g., leaking pipes, aging wastewater plants) is sometimes in acute need of being highlighted. Moreover, the work essential to keep the infrastructures maintained needs to be recognized and compensated for. Based on interviews with actors in the sewage management sector in Sweden, news articles, and public information campaigns, the present article explores how political action and public engagement are mobilized through moves between visibility and invisibility. The analysis focuses on four different modes of problematization: inproblematization, problematization, deproblematization, and unproblematization. Inscribed in the research fields of urban infrastructures and public engagement, the article sheds light on how the public secret of managing feces is upheld, through balancing acts such as creating discursive space, negotiating infrastructural disruptions, making problems treatable, and individualizing solutions. These different modes of problematization are crucial to achieving the right public attention and political measures.

Enhancing Concrete and Mortar Properties and Durability Using Pristine Graphene Particles

The usage of industrially generated graphene was explored in this work, with an emphasis on dosage effects on durability, as well as the mechanical and microstructural properties of both concrete and mortar (0%, 0.1%, and 0.2% in concrete and 0%, 0.07%, and 0.15% in mortar). Based on the mix design for wastewater infrastructure, the results showed that adding graphene to both concrete and mortar enhanced 28-day compressive strength by 10%–20%, with the best admixture level being 0.02%–0.1%. Graphene reduced the AVPV of mortar by 11.7%, and concrete by 19.3% at the optimal dosages, likely by reducing the number or size of pores in the paste. The 0.2% and 0.15% graphene reinforced concrete and mortar showed significant sulfate resistance, by reducing 62% and 60% of extension respectively, after exposure to a sulfate solution for 16 weeks.

Asset Monitoring Stretches Infrastructure Investments

It's common sense to monitor and control for factors that can influence water and wastewater infrastructure longevity. Fortunately, there are a variety of lab and field methods available to help extend the useful life of infrastructure assets.

Concept of Emergency Wastewater Infrastructure Provision in Minimizing the Impact of Potential Earthquake in Surabaya

Mass displacement to refugee camps often happens after an earthquake hits. Faecal oral transmission usually occurs causing disease outbreaks when people in mass displacement camps. Surabaya has a potential threat of an earthquake measuring 6.5 on the Richter Scale. However, equipment readiness in wastewater infrastructure is still low at 21% during the emergency response period. Therefore, this research is needed in formulating the concept of emergency wastewater infrastructure provision to minimize the side effects of disease outbreaks. This study obtained primary data from 17 respondents. The first objective uses content analysis method. Then the second objective adopted triangulation analysis derived from three types of data, respondent opinions, policies, and best practices. The first objective disclosed 46 criteria for the provision of emergency wastewater infrastructure. Meanwhile, the second objective presented 38 potential actions and 18 concepts adjusted to disaster management cycle (mitigation, preparedness, response, and recovery). The mitigation phase focuses on stocktaking materials, establishing partnerships, training for volunteers, and optimizing the existing sanitation program. The preparedness focuses on forming a team to assess the needs of post-disaster conditions. The response phases divided into acute, general, and stabilization. The general stage focuses on determining suitable infrastructure, mobilizing volunteers and materials, and coordinating between agencies or clusters to handle wastewater. The acute stage focuses on rapid assessment and procurement of materials. The stabilization stage focuses on community involvement, determining the location of infrastructure, and handling waste from wastewater treatment. Finally, the recovery phase focuses on repairing the existing affected wastewater treatment plant.

Climate Change and Onsite Wastewater Treatment Systems in the Coastal Carolinas: Perspectives from Wastewater Managers

Abstract Nearly one-half of the residents of North and South Carolina use decentralized or onsite wastewater treatment systems (OWTS). As the climate changes, coastal communities relying on OWTS are particularly vulnerable, as soil-based wastewater treatment may be reduced by water inundation from storm surge, sea level rise and associated groundwater rise, and heavy rainfall. Despite the vulnerabilities of OWTS to increased precipitation and sea level rise, there is little known about how onsite wastewater managers are responding to current and future climate risks. We conducted interviews with wastewater operators and installers and health regulators to understand the functioning, management, and regulation of OWTS in the current climate, challenges with rising sea levels and increases in extreme weather events, and what adaptation strategies could be implemented to mitigate negative impacts. Our results indicate that heavy precipitation and storm surges cause malfunctions for conventional septic systems where traditional site variables (e.g., soil type or groundwater level) are undesirable. Weather and climate are not required regulatory factors to consider in system selection and site approval, but many OWTS managers are aware of their impacts on the functioning of systems, and some are preemptively taking action to mitigate those impacts. Our findings suggest that filling gaps in the current communication structure between regulators and homeowners relying on OWTS is critical for coastal communities in the Carolinas to build climate resilience into decentralized wastewater infrastructure. Significance Statement This research aims to understand the functioning, management, and regulation of onsite wastewater treatment systems in the current climate, the challenges to these systems caused by rising sea levels and increases in extreme weather events, and the adaptation strategies that can be implemented to mitigate negative climate impacts. These results can be used by state government agencies, municipalities, and private sector wastewater managers to improve the resiliency of onsite wastewater treatment systems.

Assessment of Infiltration from Private Sewer Laterals: Case Study in Jurmala, Latvia

The presence of excess water in centralized sewerage systems is known to have a multitude of unfavorable effects on the daily operation of the wastewater infrastructure. The additional volume of I/I-water decreases the hydraulic capacity of wastewater collection networks, reduces the efficiency of wastewater treatment processes, and increases the costs of transporting and treating the wastewater. Currently, most I/I studies in Latvia are conducted on the scale of the wastewater treatment plant service area and determine only the common performance indicators for a given year. However, data of such resolution are not sufficient to identify problem areas within the networks and to introduce cost-effective measures. The contribution of private sewer laterals to the overall I/I volume is an area of particular interest. Although it is possible to locate and quantify I/I from individual house connections, in practice, given the financial and time constraints, it is not feasible to apply a case-by-case approach. Thus, a simple method to predetermine the problematic parts of the system before conducting on-site inspections is needed. This study investigates the link between groundwater levels and observed night-time wastewater flows on a sub-catchment scale by performing a linear regression analysis (940 data points in total). The results show a direct correlation (R &gt; 0.70 in all cases) between said parameters and highlight the impacts of poorly built and ill-maintained house connections. The presented approach can be widely adopted by system operators to help identify potential sources of diluted wastewater and to aid in the development of priority-based renovation plans.

Integrated asset management of urban water and wastewater systems

AbstractThis paper presents a decision support system for the integrated management of water distribution and wastewater collection networks. The proposed methodology utilizes system dynamics to integrate water mains and sewers with finance and sociopolitical sectors. It enables user rate‐setting and planning of integrated water and wastewater infrastructure operational and capital works over their life‐cycle (50+ years). The integrated asset management model is implemented using data from a large‐sized utility in Southern Ontario, Canada. The result indicates that the integrated framework enables the utility to accelerate funding for capital and operational works due to the integration of the water and wastewater financial resources and improve the integrated levels of service. In practice, the proposed integrated framework empowers and encourages water utilities to manage and plan their assets in an integrated approach to enhance their water and wastewater assets' infrastructure, financial, and sociopolitical performance relative to managing them in isolation.

Precipitation, tidal and river level impacts on influent volumes of combined wastewater collection systems: A regional analysis

Wastewater treatment plants (WWTPs) that treat both foul and storm wastewater will experience significant pressure due to changing precipitation patterns and other geophysical parameters. Limited work has been done to understand the links between factors such as tidal and river levels, precipitation, and influent volumes to WWTPs. This paper analyses the variations of precipitation and their link with influent volumes. The study adopts a new approach to understand influent volume variations by taking into consideration, the combined and individual impacts of tidal and river levels in addition to precipitation; a topic that has not been examined in literature to date. It was found that, on a daily basis, precipitation, tidal elevation, and river levels were each statistically significant in explaining variations in daily influent volumes. On a monthly scale, the combined effects of average daily precipitation and the number of zero rainfall days contributed to the changes in influent volumes. Lastly, this paper proposed monthly pooled spatio-temporal analysis to understand the variable nature of monthly averaged daily influent volumes. These findings will help stakeholders in wastewater management with long-term planning and investment including responses to changing precipitation patterns and their impact on wastewater infrastructure.

Meeting the Water and Sanitation Challenges of Underbounded Communities in the U.S.

Water and sanitation (wastewater) infrastructure in the United States is aging and deteriorating, with massive underinvestment over the past several decades. For many years, lack of attention to water and sanitation infrastructure has combined with racial segregation and discrimination to produce uneven access to water and wastewater services resulting in growing threats to human and environmental health. In many metropolitan areas in the U.S., those that often suffer disproportionately are residents of low-income, minority communities located in urban disadvantaged unincorporated areas on the margins of major cities. Through the process of underbounding (the selective expansion of city boundaries to exclude certain neighborhoods often based on racial demographics or economics), residents of these communities are disallowed municipal citizenship and live without piped water, sewage lines, and adequate drainage or flood control. This Perspective identifies the range of water and sanitation challenges faced by residents in these communities. We argue that future investment in water and sanitation should prioritize these communities and that interventions need to be culturally context sensitive. As such, approaches to address these problems must not only be technical but also social and give attention to the unique geographic and political setting of local infrastructures.

Generate_SWMM_inp: An Open-Source QGIS Plugin to Import and Export Model Input Files for SWMM

SWMM is an open-source model and software developed by the US EPA for the simulation of rainfall-runoff and routing in water bodies, sewer systems and wastewater infrastructures. It has been applied in numerous practical works and research projects. For a new SWMM model, objects such as nodes, links and catchments can either be drawn via SWMM’s graphical user interface (GUI) or specified manually in a plain text file in “.inp” format (“input file”). Since the required data regarding sewer geometries and river systems are usually available as spatial data in a GIS environment, there is a need for user-friendly interfaces for the model setup. SWMM contains neither an import function for geodata nor processing tools as provided in geographic information systems (GIS) such as the open-source software QGIS. Existing approaches were script-based or required commercial all-in-one products. We developed a free and open-source QGIS plugin to generate SWMM models from geodata and to import existing SWMM input files into QGIS. An application example is presented to demonstrate the basic features and usage of the plugin.