Wastewater network infrastructure in public health: Applications and learnings from the COVID-19 pandemic

Accurate estimates of COVID-19 burden of infections in communities can inform public health strategy for the current pandemic. Wastewater based epidemiology (WBE) leverages sewer infrastructure to provide insights on rates of infection by measuring viral concentrations in wastewater. By accessing the sewer network at various junctures, important insights regarding COVID-19 disease activity can be gained. The analysis of sewage at the wastewater treatment plant level enables population-level surveillance of disease trends and virus mutations. At the neighborhood level, WBE can be used to describe trends in infection rates in the community thereby facilitating local efforts at targeted disease mitigation. Finally, at the building level, WBE can suggest the presence of infections and prompt individual testing. In this critical review, we describe the types of data that can be obtained through varying levels of WBE analysis, concrete plans for implementation, and public health actions that can be taken based on WBE surveillance data of infectious diseases, using recent and successful applications of WBE during the COVID-19 pandemic for illustration.

Unaccounted infrastructure needs for transit-oriented developments

Increasingly, U.S. cities are focusing on transit-oriented development (TOD) policies to expand the stock of higher-density, mixed-use development near public transit stations within the context of a transit corridor and, in most cases, a regional metropolis. A TOD zone relies on a regulatory and institutional environment, public and private participation and investment, and development incentives to create vibrant, people-oriented communities and mobility options and to support business development. TODs provide local governments with more tax revenues due to increased property values (and, as applicable, income and sales tax revenues), but most planning for TODs ignores the non-transit infrastructure costs of increasing development density. This study focused on determining the water and sewer infrastructure costs for TOD zones along a rail line in southeast Florida. The finding was that millions of dollars in funds are needed to meet those water and sewer needs and that few are currently planned as a part of community capital improvement programs.

Investigating Effects of Metakaolin Content on the Physical Properties of Concrete, and its Susceptibility to Colonization and Biodegradation by Sulphur Oxidizing Bacteria

Biogenic sulphuric acid attack on concrete is a concern worldwide, as it can lead to collapse of sewer infrastructure. Despite knowledge of the cause and the degradation pathways, not much is known about colonization patterns by sulphur oxidizing bacteria. These bacteria were grown on concrete in attempts to catalog degradation and colonization patterns. This was achieved using a battery of concrete property tests and experimenting with imaging techniques. Increased metakaolin content of concrete decreased sorptivity and chloride permeability of concrete while increasing strength and porosity. Concrete with higher metakaolin appeared more resistant to biogenic acid attack, despite increased porosity. Advances were made in protocols for imaging bacteria on a concrete surface, a challenge given the presence of autofluorescing materials in concrete. Information gained has shown that imaging bacteria on an autofluorescent surface can be achieved, and recommendations are made to further advance these efforts.

Investigating Effects of Metakaolin Content on the Physical Properties of Concrete, and its Susceptibility to Colonization and Biodegradation by Sulphur Oxidizing Bacteria

Biogenic sulphuric acid attack on concrete is a concern worldwide, as it can lead to collapse of sewer infrastructure. Despite knowledge of the cause and the degradation pathways, not much is known about colonization patterns by sulphur oxidizing bacteria. These bacteria were grown on concrete in attempts to catalog degradation and colonization patterns. This was achieved using a battery of concrete property tests and experimenting with imaging techniques. Increased metakaolin content of concrete decreased sorptivity and chloride permeability of concrete while increasing strength and porosity. Concrete with higher metakaolin appeared more resistant to biogenic acid attack, despite increased porosity. Advances were made in protocols for imaging bacteria on a concrete surface, a challenge given the presence of autofluorescing materials in concrete. Information gained has shown that imaging bacteria on an autofluorescent surface can be achieved, and recommendations are made to further advance these efforts.

Long-Term Temporal Stability of the Resistome in Sewage from Copenhagen

ABSTRACT Antimicrobial resistance (AMR) is a major threat to global health, and it is crucial to understand the epidemiological aspects in order to predict the emergence and propagation of AMR genes. The aim of this study was to assess the variability and medium-term AMR trends within the mostly healthy human population of a single city. We monitored over 36 months (November 2015 to November 2018) the AMR level in the city of Copenhagen, Denmark, by taking bi-weekly sewage samples from the inlets of the three main water treatment plants, extracting the DNA, performing metagenomic sequencing, and read-mapping against a database of known AMR genes. We found that the AMR level was surprisingly stable with no periodic variability and no signs of drift over the measured period. We found, however, that the seemingly random variations at each site correlate in time with each other, suggesting that the variations we see are due to real environmental changes in the occurrence of AMR. IMPORTANCE The Copenhagen sewage resistome is surprisingly stable in time. The implication is that, at least for cities that are comparable to Copenhagen in terms of sewer infrastructure, few or even single samples provide a robust picture of the resistome within a city.

A hedonic valuation of sanitation services in Guatemala

Many developing countries lack universal sanitation services for residents. Years of inappropriate disposal of solid waste and wastewater have increased the potential for devastating environmental and health issues. An economic valuation of sanitation services may help in planning investment projects by demonstrating the benefits that households derive from having access to improved sanitation. We examine Guatemala as a case study and employ a series of hedonic models to estimate the value that households in Guatemala assign to the sanitation services of solid waste collection and connections to sewer infrastructure. Findings indicate that residents are willing to pay higher rents for both wastewater and solid waste removal. Policy implications are discussed.

From CCTV Data to Strategic Planning: Deterioration Modelling for Large Sewer Networks in Germany and Colombia

Most cities are facing an aging sewer infrastructure in extensive and emerging need of repair, rehabilitation or renewal. Deterioration modelling can be a valued data mining tool to tackle this issue by supporting utilities in defining strategic investment planning. This study aims to demonstrate the benefits of deterioration modelling using sewer CCTV inspection data and GIS characteristics (material, age, depth, width, traffic load, etc.) of two different cities: Braunschweig in Germany and Bogota in Colombia. A probabilistic Markov-based model has been applied to identify and exploit relationships between sewer condition and characteristics in the extensive datasets of the two cities. The quality of prediction of the model has been evaluated by analyzing the deviation between model observations and model predictions. Results show relatively low deviations (< 15%) indicating a satisfying model performance in both cities and underlining the relevance of deterioration models to simulate the condition of sewer networks and to support strategic asset management.