COVID-19 and Sewer Deterioration

COVID-19 and Sewer Deterioration: From One Year In to Several Years Out

Here we are folks! More than a year into the COVID- 19 pandemic, which upended every area of our lives, and brought tragedy and loss to some of us. For those of us professionals involved in maintenance and construction projects who work to support our underground wastewater infrastructure, here is a snapshot of how the COVID-19 pandemic has impacted, and will continue to impact, our aging sewer infrastructure for years to come; as well as provide a more immediate outlook for the sewer services industry throughout the U.S.

Let’s look at some of the immediate impacts. As we all remember from the initial lockdown in the spring of 2020, Americans, fearing a sustained period of mandatory quarantine, went on a panic-buying spree for toilet paper, and as some chose to stockpile large amounts of bathroom tissue, many others experienced scarcity as stores ran out of stock. This contributed to an increase in the use of “wet wipes” being flushed down toilets. These materials, which are not designed to dissolve as toilet paper does, were disruptive to the municipal wastewater collection system and created blockages in pipes, manholes, lift station pumps, and at the critical headworks of treatment plants.

Add to this, there have been anecdotal reports of sewer maintenance workers in the U.S. finding clogs in wastewater pipes due to people flushing face masks down toilets, and discarded masks entering conveyance mainlines from surface water drains to combine with other debris to form large deposits that can be difficult to remove.

In addition to the operations and maintenance difficulties from wet wipes and face masks, we have, since the initial lockdowns first commenced, experienced an unprecedented shift in the locations and patterns of wastewater flow levels in collection systems through the U.S., particularly in suburbs and areas with major office spaces. Due to nearly all office employees suddenly working remotely, and with travel highly restricted, flow monitoring data in residential areas immediately showed us high flow levels that went from a two-day a week level (because of weekends) to a seven-day a week constant state.

“ Many public entities are currently seeing huge declines in tax revenues and collection
issues from ratepayers impacted by sudden high unemployment due to closures from
COVID protocols.”

Now, this is not to say data demonstrates there to be an overall higher level of flow across all collection systems, however, we are likely to see a longterm shift in the point-source locations of these wastewater flows could have at least two major long-term impacts on their collection systems:

First, if residential areas (consisting of entire drainage basins in certain collection systems) experience sustained periods of higher “weekend” flow levels that could accelerate deterioration of these already aged and deteriorated pipes. If a particular pipe segment had historically only had to convey these higher flows two days a week, and then suddenly the pattern shifts to seven days a week for longer than a year, one could expect any pre-existing fissures, voids, or joint separations to worsen.

Second, is the effect of sustained periods of low flows in major commercial areas of the collection system. These more densely populated and urban areas tend to have larger diameter gravity conveyance mainlines to service the normally higher flow volumes. With this sustained period of low flow, one can expect this to result in operation and maintenance issues, as the current hydraulics may be insufficient to convey solids downstream, causing not just blockages, but also creating an additional deterioration mechanism: corrosion resulting from hydrogen sulfide gas (H2S attack). As these blockage points create or simulate a septic condition in the sewer, the formation of hydrogen sulfide gas results once these materials eventually aerate and oxidize due to high flow events and turbidity. As all of us in the wastewater industry know, corrosion from hydrogen sulfide gas attack, in addition to being a deadly job safety hazard for sewer workers, is a major problem for structures made with cementitious materials, which are commonly used in horizontal conveyance and vertical access structures.

Another major disruption from COVID has been financial. Although there was not a measurable overall decline in maintenance and construction projects in the sewer services industry attributable to COVID-19 in 2020, when one considers the long-term economic realities, there appears to be trouble ahead. Many public entities are currently seeing huge declines in tax revenues and collection issues from ratepayers impacted by sudden high unemployment due to closures from COVID protocols. Overall, these impacts will be in the billions of dollars.

This is the opposite of what has been needed for municipal maintenance and capital construction funding levels. Preexisting funding shortfalls have long been documented and lamented by folks throughout our industry. The American Society of Civil Engineers (ASCE) in 2021 even assigned a D+ (poor/at risk) grade to our aging wastewater infrastructure.

Despite this, there are two areas that offer us hope. We have seen an apparent increase in political will to carry out major infrastructure spending. It is extremely important for those in our industry to continue to advocate for prioritizing federal infrastructure spending.

Another promising development that gives hope is the emergence of new technologies, particularly Artificial Intelligence (AI), and its increased adoption in our industry. When COVID-19 lockdowns happened, organizations large and small turned to new technologies to enable us to carry out tasks in our professional and personal lives, and AI, also referred to as Machine Learning (ML), has been responsive as well. Our industry, because of AI, was able to prove itself as a valuable frontline force in the fight against COVID-19, with wastewater sampling combined with advanced analytics enabling scientists to detect (and in some cases even predict) the spread of the disease in our communities.

AI has had a huge impact relative to an otherwise more costly and time-consuming aspect of wastewater collection system maintenance, the use of robotic inspection cameras to constantly collect images of the interior of pipes and maintenance holes, and the time and cost required to analyze the data into useful condition reports.

Sophia Soka, Director of Finance at East Bay Municipal Utility District, said it well recently while speaking at a workshop on Digital Asset Management, when describing an ongoing project with an AI Software as a Service (SaaS) vendor, “We are using machine learning to rapidly identify pipes for replacement, which will allow us to reduce infiltration and inflow into our regional collection system. This technology really takes advantage of our existing practices, leveraging data we already have. We have limited budgets, more constraints due to regulation, and more asks from the public. Income inequality means that affordability is high on our list of objectives. So, we’re hoping technologies like this are going to enable us to better manage our assets on behalf of our ratepayers in a more cost-effective manner.”

This will continue to be the trend, even as our communities finally begin to fully emerge from more than a year of lockdowns and economic uncertainty due to COVID-19. There still remain systemic issues contributing to funding shortfalls at utilities that will continue to pull for the adoption of new technologies and new types of results. According to Greg Baird, President of the Water Finance Research Foundation, “aging infrastructure and compliance issues are driving up costs for sewer utilities, putting more pressure on affordability concerns. Utilities are looking to leverage AI/digital solutions and technologies to reduce costs and increase efficiencies while protecting the public health.”

Eric Sullivan is Director of Business Development with Sewer AI. He can be reached at esullivan@ help

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