Steam floating out of the discharge stack, unusual sounds, and unfamiliar equipment are all things that can be found at a thermal remediation site. These factors, along with the presence of process equipment, safety fences, and potential lack of knowledge of the project, can cause anxiety and fear for the untrained person, especially if the site is located next to residential homes.
We fully understand that having a thermal wellfield next to a house, school, or shopping center can lead to stakeholder concerns, and part of our process is to provide our clients with support to educate the community on how thermal soil remediation in residential neighborhoods works and how it can be safely implemented.
Thermal systems by design are complex and often involve substantial above-ground treatment equipment, which is generally not familiar to the public.
Let’s break it down and look at how safe it is to perform thermal soil remediation in residential neighborhoods.
Are there Emissions?
Seeing a stack pushing steam into the atmosphere can be concerning to neighbors. The chemicals that are removed from the subsurface by the thermal remediation system are treated by TerraTherm using extensive state-of-the-art treatment technologies to remove the dangerous chemicals from the discharge streams. The vapor exiting the stack can be compared with the steam created when boiling water on the stove. Our trained and experienced system operators respond to the site within 30 minutes, day, or night, in the event that a system warning or alarm is triggered. Our thermal treatment systems are all equipped with installed spares of critical system components, such that repairs and replacements can be completed with a minimum of system downtime and typically include an automatic transfer switch and emergency generator to keep the effluent treatment system operating in the event of a loss in grid power.
Every thermal project is subject to local air and liquid discharge permitting and monitoring rules, and discharge streams from our thermal treatment systems are monitored daily. Unusual smells may occasionally be noticed around the thermal system, ranging from hot steel piping or concrete, or because for instance increased biological degradation is happening in the liquid system at elevated temperatures. While these smells may be unusual, they are generally intermittent and they aren’t dangerous, much like smells you may find in a laundry basket. Our thermal system operators are on site 6 or 7 days a week and monitor the stack emissions and ambient air around the site with handheld instruments and regularly collected laboratory analytical samples.
In cases where the site owners, consultants or neighborhood stakeholder may feel safer by having more information, we can provide real-time monitoring of air concentrations with devices such as a real-time Fourier Transform Infra-Red (FTIR) monitoring system. The data the FTIR collects can easily be uploaded to the project website, providing stakeholders access to real-time stack emission and ambient air concentrations around the perimeter of the site.
Thermal remediation is safe to be used in populated neighborhoods. We have successfully applied thermal remediation to treat sites immediately adjacent to occupied residences and commercial buildings, and even under occupied buildings. Careful attention to design details, proper design of the extraction and treatment system, an effective monitoring program, and open and honest communication with neighbors or other key stakeholders are the key to successfully implementing a thermal remediation project in a residential neighborhood.
Is the wellfield Safe?
Thermal remediation wellfields contain live power, often at voltages up to 480 volts. They also contain pipes with steam, hot vapors, and liquids. The high temperatures in the thermal wellfield require use of proper personal protective equipment (PPE). To limit the potential for access by unauthorized or untrained individuals, the thermal wellfield is fenced in and only accessible to operators and technicians who not only have the correct Occupational Safety and Health Administration (OSHA) training but also understand the health and safety plan for the site and have been informed of the site-specific hazards and PPE requirements by the lead thermal system operator. Intrusion alarm and monitoring systems are often installed to inform the site operator of any unauthorized access in the wellfield. In densely populated neighborhoods, security guards can be posted on the site to prevent unauthorized access to the site at the client’s or city’s discretion.
Sound generation is also a common focus due to the size of the extraction and treatment equipment that is often required. Therefore, the equipment can be housed in a container, shed, or placed behind sound reducing barriers to reduce ambient noise below the local municipality’s noise standards for residential neighborhoods. We utilize decibel monitoring systems to document that noise is kept under acceptable limits and we can readily retrofit equipment with additional noise mitigation measures during testing and startup to ensure compliance with local noise ordinances, to ensure that nearby residents are not disturbed by the operating treatment equipment.
So, is it safe?
Thermal remediation is safe to implement in populated neighborhoods. The whole system is designed to prevent fugitive emissions and treat all extracted liquids and vapors with treatment system components that are properly designed to treat all the subsurface chemicals, and properly monitored to ensure compliance with discharge limits. We strongly believe that the best way to address concerns is to provide our clients with the support and information they need to educate the local community about what is happening, why it is happening, and how we will ensure the safety of nearby residents and other stakeholders throughout the thermal remediation project. We are always willing to address any concerns there may be and provide data and documentation as needed.
While thermal remediation may seem “scary” to people who have not seen a thermal site in operation, the real scary problem is the chemicals in the ground. The consequences of leaving these subsurface chemicals untouched can be severe, and far outweigh the potential concerns or minor inconveniences of installing and operating a thermal treatment system. When properly designed and operated, thermal remediation is a safe process for rapidly removing dangerous chemicals from the ground in a well-regulated process.
We fully understand the concerns that accompany such a project, especially in a residential neighborhood, and are more than willing to add any measures to help our clients and the local community feel safe and at ease.
Contact me today if you want to learn more about projects that we have completed for thermal soil remediation in residential neighborhoods or have a site you would like to discuss.
Sam Nienstedt is TerraTherm’s Technologist. He keeps the project management team informed of projects’ statuses by monitoring and processing real-time operational data that comes in from the field and preparing operational reports. As part of the Technology Team, Sam assists the team with proposals, work plan preparations, and engineering field support during construction, commissioning, and…