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.

Impacts of COVID-19 social distancing policies on water demand: A population dynamics perspective

Social distancing policies (SDPs) implemented in response to the COVID-19 pandemic have led to temporal and spatial shifts in water demand across cities. Water utilities need to understand these demand shifts to respond to potential operational and water-quality issues. Aided by a fixed-effects model of citywide water demand in Austin, Texas, we explore the impacts of various SDPs (e.g., time after the stay home-work safe order, reopening phases) using daily demand data gathered between 2013 and 2020. Our approach uses socio-technical determinants (e.g., climate, water conservation policy) with SDPs to model water demand, while accounting for spatial and temporal effects (e.g., geographic variations, weekday patterns). Results indicate shifts in behavior of residential and nonresidential demands that offset the change at the system scale, demonstrating a spatial redistribution of water demand after the stay home-work safe order. Our results show that some phases of Texas's reopening phases had statistically significant relationships to water demand. While this yielded only marginal net effects on overall demand, it underscores behavioral changes in demand at sub-system spatial scales. Our discussions shed light on SDPs' impacts on water demand. Equipped with our empirical findings, utilities can respond to potential vulnerabilities in their systems, such as water-quality problems that may be related to changes in water pressure in response to demand variations.

Human-Infrastructure Interactions during the COVID-19 Pandemic: Understanding Water and Electricity Demand Profiles at the Building Level

When engineers design and manage a building's water and electricity utilities, they must make assumptions about resource use. These assumptions are often challenged when unexpected changes in demand occur, such as the spatial and temporal changes observed during the coronavirus (COVID-19) pandemic. Social distancing policies (SDPs) enacted led many universities to close their campuses and implement remote learning, impacting utility consumption patterns. Yet, little is known about how consumption changed at the building level. Here, we aim to understand how water and electricity consumption changed during the pandemic by identifying characteristic weekly demand profiles and understanding how these changes were related to regulatory and social systems. We performed k-means clustering on utility demand data measured before and as the pandemic evolved from five buildings of different types at the University of Texas at Austin. As expected, after SDPs were enacted both water and electricity use shifted, with most buildings seeing a sharp initial decline that remained low until the university partially reopened. In contrast to electricity use, we found that water use was tightly coupled with SDPs. Our study provides actionable information for managers to mitigate negative impacts (e.g., water stagnation) and capitalize on opportunities to minimize resource use.

Resilient Water and Wastewater Infrastructure Systems through Integrated Humanitarian-Development Processes: The Case of Lebanon's Protracted Refugee Crisis

When populations are displaced, say after a hurricane or a man-made crisis, water and wastewater utilities can face a real challenge in providing services to those displaced. The challenge is especially difficult when the local infrastructure was already strained in trying to meet the host community's pre-displacement demand. What most communities need are resilient water and wastewater infrastructure systems, and what we develop in this paper is an integrated approach that can achieve such systems. Our approach takes into account the operating environment of bridging what some call the humanitarian-development (HD) nexus. The HD nexus is the phase in which a community transitions toward a response paradigm that combines humanitarian response with long-term services. The HD nexus poses inherent contextual challenges, and we identify them, through interviews with municipalities in Lebanon, in their physical, social, financial, and institutional dimensions. Furthermore, we explore interactions that can inform how best to address these challenges. Our results introduce policy areas (i.e., utility pricing and establishing shared development priorities) that support this transition across the HD nexus and achieve resilient systems. Our discussions give rise to an empirical understanding of the infrastructures' operating environments and thus contribute to global conversations on sustainable development.

Implications of Social Distancing Policies on Drinking Water Infrastructure: An Overview of the Challenges to and Responses of U.S. Utilities during the COVID-19 Pandemic

Social distancing policies (SDPs) implemented throughout the United States in response to COVID-19 have led to spatial and temporal shifts in drinking water demand and, for water utilities, created sociotechnical challenges. During this unique period, many water utilities have been forced to operate outside of design conditions with reduced workforce and financial capacities. Few studies have examined how water utilities respond to a pandemic; such methods are even absent from many emergency response plans. Here, we documented how utilities have been impacted by the COVID-19 pandemic. We conducted a qualitative analysis of 30 interviews with 53 practitioners spanning 28 U.S. water utilities. Our aim was to, first, understand the challenges experienced by utilities and changes to operations (e.g., demand and deficit accounts) and, second, to document utilities' responses. Results showed that to maintain service continuity and implement SDPs, utilities had to overcome various challenges. These include supply chain issues, spatiotemporal changes in demand, and financial losses, and these challenges were largely dependent on the type of customers served (e.g., commercial or residential). Examples of utilities' responses include proactively ordering extra supplies and postponing capital projects. Although utilities' adaptations ensured the immediate provision of water services, their responses might have negative repercussions in the future (e.g., delayed projects contributing to aging infrastructure).

4D-BIM to enhance construction waste reuse and recycle planning: Case studies on concrete and drywall waste streams

Despite pressing attention on construction waste management (CWM) issues, low rates of construction waste (CW) reuse and recycling (R&R) remain a limitation in construction projects. In recent years, Building Information Modeling (BIM) has gained momentum for CWM purposes; its data-richness, visualization, and simulation capabilities provide an opportunity to enhance CW R&R planning at the project level. In this context, this study proposes temporal-based algorithms integrated with 4D-BIM for the planning of concrete and drywall waste R&R throughout construction projects. Two case studies from Central Texas were used for the demonstration of the algorithms, and estimates were validated with ground truth data and literature values from different projects in North America. The overarching objective of the proposed algorithms is to streamline estimation and visual planning of CW for on-site reuse, and off-site recycling - therefore promoting a more proactive and schedule-based CWM plan. In addition, the approach improves team communication around CWM goals of the project. Moreover, through the use of 4D-BIM, on-site waste reuse opportunities are planned in advance, thus, improving resource recovery and minimizing waste disposal in landfills.

Prevalence of Intestinal Parasites in a Low-Income Texas Community

Strongyloidiasis affects an estimated hundreds of millions of people worldwide, with infection possibly persisting for life without appropriate therapy because of the helminth's unique autoinfection cycle. Like other soil-transmitted helminths, because of the environmental conditions required for the life cycle of Strongyloides stercoralis, this parasite is endemic to tropical, subtropical, and temperate countries and areas with inadequate sanitation infrastructure. Given continued poverty and that nearly one in five American homes are lacking proper sanitation systems, many U.S. regions are at risk for intestinal parasites. A central Texas community was chosen as the study site, given previous reports of widespread sanitation failure, degree of poverty, and community willingness to participate. A total of 92 households were surveyed and residents tested for nine intestinal parasites using a multi-parallel quantitative real-time polymerase chain reaction and ELISA serology. From 43 stool samples, 27 (62.8%) tested positive for Blastocystis spp. and one (2.3%) for Giardia lamblia. From 97 serum samples, Strongyloides serology detected 16 (16.5%) positive individuals. These high rates of heterokont and helminthic laboratory findings in a peri-urban central Texas community suggest several key policy implications, including that strongyloidiasis should be added to the Texas notifiable conditions list, that clinical suspicion for this infection should be heightened in the region, and that residents without access to functioning and sustainable sanitation infrastructure should be provided that access as a basic human right and to promote public health.

Construction waste generation estimates of institutional building projects: Leveraging waste hauling tickets

The large proportions of waste generated from the construction industry have led to adverse environmental and socio-economic impacts, and as such, there is a need to promote construction waste management (CWM) practices. However, there is limited information regarding construction waste (CW) generated from nonresidential buildings available to support such CWM practices. This study seeks to quantify CW generated from a nonresidential institutional building project using CW data collected from 535 waste hauling tickets. These tickets provide a waste generation summary itemized by various CW streams. The CW data was collected through coordination with the project waste management team. Findings reveal that concrete/masonry is the highest waste stream during the Foundation (46% of CW) and Structural Concrete (88% of CW) stages. During the Masonry Work and Finishing Stage, wood is found to be the primary contributor (54% of CW), followed by concrete/masonry (35.3% of CW). The estimated CW generation rate was approximately 69 kg/m², with the concrete/masonry and wood waste streams having the highest generation rates of 33.61 kg/m² and 28.21 kg/m², respectively, comprising 90% of the total CW across the project. Due to the temporal characteristics of different waste streams, varying CW dumpsters available onsite is recommended based on the construction stage, to mitigate space shortage impacts. Furthermore, this study quantifies the benefits of recycling CW as environmental savings of trees, water, energy and greenhouse gas emissions. Findings of this study would help refine the accuracy of the reported estimates of CW generation for nonresidential construction projects. By shedding light on the corresponding handling practices of the generated waste and project management processes applied on institutional projects, the study can also serve as a guide to better plan for and coordinate the management of CW of these projects. Results may be used to promote and encourage the adoption of CWM practices at the site level to improve the sustainability performance of the construction industry.

BIM-based automated construction waste estimation algorithms: The case of concrete and drywall waste streams

Globally, the growth of construction activities over the past years has resulted in large quantities of waste generation. Much of this waste is not reused or recycled and is subsequently redirected to landfills. The environmental impact of construction waste (CW) generation and the shortage of land resources for the creation of new landfills have reinforced the need to adopt more innovative CW management practices. Estimation of CW is a necessary step for the adoption of CW management practices. In this study, Building Information Modeling (BIM) is used to automate CW quantification. In this context, CW generation is estimated as the materials purchased but not incorporated into the actual building structure. Algorithms developed to quantify concrete and drywall waste streams are presented to demonstrate the proposed CW estimation method. The proposed concrete algorithm is validated by comparing estimated waste to actual waste data reported in the waste hauling tickets of a real-world project. Furthermore, CW generation quantities reported in the literature are used to validate estimates of both concrete and drywall waste streams. By leveraging material quantities directly from BIM-as opposed to manual estimations-CW estimation can be streamlined, enabling decision makers to implement more efficient construction waste management practices in the field.

Transitioning from a Human Right to an Infrastructure Service: Water, Wastewater, and Displaced Persons in Germany

Water and sanitation utilities across Europe have recently been challenged to provide services to asylum seekers and refugees fleeing complex humanitarian disasters. We explore public perceptions regarding how secondary disaster impacts (mass migration into an undamaged area) has impacted the utilities. We show that the hosting population is typically willing to provide water and sanitation services to displaced persons for a set period of time, even if the displaced persons are unable to pay (water and sanitation as human rights). However, as time passes, displaced persons are eventually expected to pay for access (water and sanitation as infrastructure services). Drawing from statistical modeling of survey data from German residents, we find the average length of time for this transition in 2016 Germany was 2.9 years. The data also show statistically significant demographic and locational attributes that influence this time frame, indicating the normative length of the transition from a right to a service is contextually dependent. Regardless, this is a significant period of time that the public expects utilities to provide services to unexpected displaced persons. To be able to meet this kind of demand, utilities, engineers, and policy makers must consider the potential for displaced populations in their regular, long-range utility planning.