 In part one of the series, we learned more about Stormwater Management. This second installment of the series focuses on Wastewater management, which is one of the most important — and least visible — public services in any community. It works quietly beneath our streets and behind the scenes, treating everything that leaves our sinks, showers, toilets, businesses, and industries before that water ever touches the natural environment again. In Ontario, wastewater systems are built on a simple promise: No drop of used water should return to nature without being cleaned, tested, and proven safe. To uphold that promise, municipalities like St. Thomas operate under strict provincial regulations and use a combination of advanced engineering, real-time monitoring, and ongoing investment in infrastructure. Here’s how it all works. The Journey Begins: Collecting Wastewater Safely Every time someone turns on a tap, flushes a toilet, runs a dishwasher, or operates equipment in a workplace, wastewater begins a quiet journey. In St. Thomas, that journey starts with a network of sanitary sewers — purpose-built pipes designed to safely move wastewater away from homes, businesses, and industrial sites and toward a centralized treatment facility. These pipes are not interchangeable with storm drains. They are part of a completely separate system, and that separation is one of the most essential principles in modern wastewater management. Sanitary sewers are engineered to do several critical things at once. They keep wastewater isolated from rain and snowmelt, ensuring sudden storms don’t overwhelm the system. They are sealed to prevent groundwater from seeping in, which could dilute treatment processes and strain capacity. At the same time, they are designed to prevent wastewater from leaking out into surrounding soil or nearby waterways, protecting both the environment and public health. And they are sized and graded to maintain steady flow, even during peak periods when demand is high. This separation between wastewater and stormwater is intentional — and essential. When rainwater and wastewater mix, treatment plants can be pushed beyond their limits, increasing the risk of bypasses or untreated releases. By keeping the systems distinct, each type of water can be managed properly: stormwater slowed, filtered, and released back into the environment, and wastewater fully treated through a controlled, multi-stage process. In practice, this means that long before wastewater reaches a treatment plant, it has already been carefully guided, contained, and protected. The sanitary sewer network acts as the first safeguard in a much larger system — one designed to keep neighbourhoods healthy, waterways clean, and communities like St. Thomas functioning safely every day.  The First Line of Defense: The St. Thomas Wastewater Reclamation Facilities Once wastewater leaves homes, businesses, and industrial sites, it arrives at one of the most important pieces of civic infrastructure in the community: the Water Reclamation Facility. A Water Reclamation Facility is what modern wastewater treatment plants are now called — and the name matters. These facilities don’t simply “dispose” of wastewater. They clean it, restore it, and return it safely to the environment, meeting strict provincial standards every step of the way. In many cases, the treated water leaving a reclamation facility is cleaner and more carefully monitored than the natural waterways receiving it. St. Thomas is preparing for the future by operating two Water Reclamation Facilities:
Together, these facilities form the backbone of the City’s wastewater system — a system built not just for today, but for the St. Thomas of tomorrow. Why Two Facilities? Planning for a Growing, Changing City It’s easy to assume that expanding wastewater capacity is driven by industrial growth alone — but that’s only part of the story. Communities grow naturally. Families expand. Housing increases. Neighbourhoods densify. Health care facilities, schools, and small businesses place new demands on infrastructure. Even without a single new industrial employer, population growth alone requires additional wastewater capacity to ensure systems remain reliable and compliant. At the same time, wastewater treatment itself has evolved. New environmental standards, improved treatment methods, and advances in monitoring technology all require upgrades that older facilities were never designed to accommodate. Expanding capacity allows the City to:
In short, expansion is about resilience and responsibility, not reaction.  A Layered Defense Against Environmental Risk Water Reclamation Facilities serve as the first major checkpoint in protecting both public health and the environment. When wastewater arrives, it doesn’t move straight back to nature. Instead, it enters a carefully controlled, multi-stage treatment process designed to remove solids, break down organic material, eliminate harmful bacteria, and reduce nutrients that could otherwise damage ecosystems downstream. By distributing treatment across two facilities, St. Thomas strengthens its ability to manage flows safely, adapt to future growth, and ensure that no single system bears the entire load. This redundancy is a hallmark of well-planned municipal infrastructure — quiet, intentional, and essential. In many ways, these facilities are the city’s environmental sentinels. They work continuously, day and night, in all weather, safeguarding waterways and communities alike. And as St. Thomas continues to grow and evolve, the Sunset Road and Dalewood Water Reclamation Facilities will remain central to that story — proof that infrastructure planning is about foresight, not just response.  How Wastewater Is Treated: From Arrival to Release When wastewater arrives at a Water Reclamation Facility, it doesn’t rush through the system. Instead, it begins a carefully sequenced journey — one designed to mirror natural purification processes, but with the precision, consistency, and oversight that public health and environmental protection demand. Each stage of treatment serves a specific purpose. Together, they create a layered system that ensures wastewater is thoroughly cleaned before it ever returns to the environment. Primary Treatment: Removing What You Can See The first stage focuses on physical separation — removing materials that don’t belong in water and would interfere with later treatment stages if left behind. Primary treatment is designed to:
Secondary Treatment: Letting Biology Do the Heavy Lifting Once visible material is removed, treatment becomes biological. Secondary treatment uses carefully managed microorganisms to break down dissolved organic matter; the same natural process that occurs in rivers and wetlands but accelerated and controlled within the facility. This stage is designed to:
Solids Treatment & Resource Recovery: Closing the Nutrient Loop As part of the treatment process, solids separated from wastewater are not treated as waste — they are treated as a resource. Both the Sunset Road Water Reclamation Facility (SWRF) and the Dalewood Water Reclamation Facility (DWRF) use LYSTEK technology to process biosolids. LYSTEK uses controlled heat and mechanical treatment to break down solids, producing a stabilized, nutrient-rich resource that can be safely reused. This process offers several important benefits:
By using LYSTEK, St. Thomas turns what was once considered waste into something useful, supporting both environmental stewardship and fiscal responsibility.  Tertiary and Advanced Treatment: Polishing the Water The final stage focuses on precision and protection. By the time wastewater reaches this point, it is already significantly cleaner — but tertiary treatment ensures it meets or exceeds Ontario’s strict environmental standards. Depending on facility design, advanced treatment may include:
In St. Thomas, advanced treatment reflects both proven practice and forward-looking design. The existing Sunset Road Water Reclamation Facility uses ultraviolet (UV) disinfection, meaning treated wastewater is sterilized using ultraviolet light before release — a chemical-free method that effectively neutralizes bacteria and viruses while protecting aquatic life. The Dalewood Water Reclamation Facility, currently under construction, will build on this approach by incorporating UV disinfection alongside disc filtration technology. Disc filters provide an additional polishing step, removing very fine particles and further improving water clarity and quality before discharge. Why the Stages Matter Together Each treatment layer builds on the one before it:
Together, these stages transform wastewater into water that is clean, stable, and safe to return to the natural environment — supporting healthy waterways and a growing community.  Protecting the Environment: Where the Treated Water Goes By the time wastewater reaches the end of the treatment process, it has already passed through multiple layers of physical, biological, and advanced treatment. But the final and most important question remains: where does that water go next? In Ontario, treated wastewater is never released casually. It is returned to the natural environment only after it meets strict provincial standards designed to protect ecosystems, downstream communities, and water users. In St. Thomas, this careful transition from treatment facility to natural waterway is guided by regulation, science, and constant oversight. Treated effluent from St. Thomas’ Water Reclamation Facilities is discharged to approved receiving waters only under the conditions set out in the City’s Environmental Compliance Approvals (ECAs) and must comply with Ontario Water Resources Act (OWRA). These approvals establish clear limits on what can be released— ensuring that water leaving the system is safe, stable, and compatible with the environment it enters. Before any release, treated water must meet requirements related to:
These limits are not arbitrary. They are designed to protect fish habitat, maintain oxygen levels in waterways, prevent nutrient overload, and support healthy aquatic ecosystems.
Safeguarding Local Waterways and Downstream Communities In St. Thomas and across Ontario, wastewater systems are designed with the understanding that water doesn’t stop at municipal boundaries. What is released here becomes part of a much larger watershed system, influencing downstream creeks, rivers, wetlands, and agricultural lands. By carefully controlling the quality and timing of treated effluent releases, wastewater treatment helps:
In many cases, treated effluent can actually help support environmental flows during dry periods, providing consistent water levels that benefit aquatic habitat when natural flows are low. Oversight That Continues Beyond the Plant Environmental protection doesn’t end at the discharge point. Ongoing monitoring ensures that:
Provincial regulators, conservation authorities (Kettle Creek and Catfish Creek), and municipal staff all play a role in ensuring that treated water continues to support — not harm — the surrounding environment.  Why This Matters for St. Thomas As St. Thomas grows, protecting local waterways remains a shared responsibility. Wastewater management is one of the most direct ways the City ensures that growth does not come at the expense of environmental health. By treating wastewater thoroughly and releasing it responsibly, the City protects:
This final step in the wastewater journey reflects the same principle that guides the entire system: used water can return to nature safely — when it is treated with care, respect, and accountability. For instance, extensive testing is completed at outlets to ensure that nutrient outflows don’t negatively impact the downstream system. For the new Dalewood Water Reclamation facility most parameters are quite similar except for phosphorus levels. While phosphorus is a vital nutrient essential for life, too much of a good thing can be problematic. Phosphorous limits at the new plant are 0.1 mg/L, 0.9 mg/L lower than the existing plant. The lower phosphorous limit is generally attributed to the fact that Dalewood reservoir (which is just upstream of the outlet) is eutrophic and contributes a lot of nutrients to Kettle Creek to begin with therefore very little could be added while maintaining a balanced ecosystem.  Industrial Wastewater Controls: Extra Safeguards Not all wastewater is the same. While water from homes and small businesses follows a predictable path, industrial wastewater can carry different characteristics depending on the process that created it. Because of this, Ontario’s wastewater framework adds extra layers of protection for industrial discharges — ensuring municipal systems remain safe and effective for everyone they serve. In St. Thomas, industrial wastewater is carefully managed so that what enters the municipal sewer system does not disrupt treatment processes or threaten the environment downstream. This approach protects the treatment facilities themselves, the natural waterways they discharge into, and the broader community. Pretreatment Before the Sewer Many industrial users are required to treat their wastewater before it ever reaches the municipal sewer. This pretreatment ensures that water entering the system meets defined limits and behaves predictably during treatment. Depending on the nature of the operation, pretreatment may include:
Sewer Use Bylaws and Discharge Limits St. Thomas enforces industrial wastewater controls through a Sewer Use Bylaw, which aligns with provincial standards and best practices. This bylaw sets clear limits on what can be discharged into the sanitary sewer system. These limits help:
Industrial discharges are monitored to ensure compliance, and corrective action is required if limits are exceeded. Monitoring, Sampling, and Accountability Industrial wastewater management is built on verification, not assumption. Industrial users may be required to:
Protecting the Whole System These extra safeguards are not about restricting industry — they are about ensuring compatibility. When industrial wastewater is properly managed, it:
 Continuous Monitoring: Accuracy Over Assumptions Wastewater treatment is not something that happens in the background and then fades from view. In Ontario, it is audited constantly, measured continuously, and reviewed regularly. In St. Thomas, the wastewater system operates on a simple principle: decisions are based on data, not assumptions. From the moment wastewater enters a Water Reclamation Facility, it is monitored — not just occasionally, but 24 hours a day, 7 days a week, 365 days a year. This continuous oversight ensures that treatment processes remain stable, responsive, and fully compliant under all conditions, from quiet overnight flows to intense weather events. At St. Thomas’ facilities, this monitoring takes many forms. Operators carry out daily process inspections, walking the plant, checking equipment, and confirming that each stage of treatment is functioning as designed. At the same time, computerized control systems track flows, oxygen levels, temperatures, chemistry, and system performance in real time. These systems provide immediate alerts if conditions shift, allowing staff to respond quickly and decisively. Regular laboratory testing adds another layer of verification. Samples are collected and analyzed to confirm water quality throughout the treatment process, ensuring that regulatory limits are met consistently — not just at the point of discharge, but at every critical step along the way. Operators also make operational adjustments based on weather, system load, and wastewater chemistry, fine-tuning processes to maintain optimal performance as conditions change. Accountability extends beyond daily operations. St. Thomas submits annual reports to provincial regulators, documenting performance, compliance, and system status. The City also participates in audits and unannounced inspections conducted by the Ministry of the Environment, Conservation and Parks (MECP), which provide independent oversight and reinforce transparency. These reviews ensure that monitoring practices remain rigorous and that standards are upheld without exception. This continuous cycle of monitoring, testing, adjustment, and reporting transforms wastewater treatment from a static facility into a living system — one that learns, adapts, and improves over time. It is how the City ensures that every litre of treated water meets the expectations placed on it, protecting public health, safeguarding waterways, and maintaining the trust of the community it serves.
Infrastructure Investment: Preparing for Growth Communities are not static. They grow, change, and evolve — and the infrastructure that supports them must evolve as well. In St. Thomas, planning for wastewater capacity is not about reacting to a single project or moment in time. It is about anticipating growth, managing risk, and ensuring the system remains reliable for decades to come. As St. Thomas grows — both in population and in employment — wastewater capacity must grow alongside it. New homes, denser neighbourhoods, expanded health care, schools, and everyday commercial activity all increase demand on the system. At the same time, older infrastructure requires renewal, and modern treatment standards call for more advanced processes than those used in the past. This long-term approach is reflected in ongoing investment across the wastewater system, including:
Just as important is how this growth is funded. Industrial tenants contribute through water usage fees and their role in the City’s tax base, helping ensure that the cost of expanded capacity is shared fairly. Growth pays for growth, reducing pressure on residential ratepayers and supporting long-term financial sustainability. This is what responsible infrastructure planning looks like: building ahead of need, investing before systems are stressed, and making sure that as St. Thomas grows, its wastewater system continues to protect public health, safeguard the environment, and support a strong, balanced community.  Why This Matters: Health, Environment, and Long-Term Sustainability Wastewater management is often invisible, but its impact touches nearly every part of daily life. When it works well, it protects people in ways we rarely notice — and that’s exactly the point. Behind the scenes, the system safeguards health, preserves natural spaces, and supports the long-term resilience of the community. At its most fundamental level, wastewater management protects public health. By collecting and treating wastewater safely, the system prevents the spread of disease, keeps harmful bacteria out of waterways, and ensures that what leaves homes and businesses does not return as a health risk. This protection is constant, reliable, and essential to the well-being of the entire population. Beyond human health, wastewater management plays a critical role in protecting the environment that surrounds St. Thomas. Treated water is released in a way that safeguards local waterways such as Kettle Creek, maintaining water quality and supporting the ecosystems that depend on it. Fish, amphibians, birds, and insects rely on stable, clean aquatic environments — and wastewater treatment helps ensure those habitats remain healthy and resilient. The system also supports agriculture and drinking water sources. By protecting surface water and groundwater recharge zones, wastewater management helps maintain clean water for irrigation, protects wells and aquifers, and reduces the risk of contamination that could impact food production or drinking water supplies. Recreational areas — from trails and green spaces to fishing and natural gathering places — benefit as well. Clean water supports safe recreation and preserves the natural features that make the region a place people want to live, work, and spend time outdoors. Perhaps most importantly, wastewater management protects downstream communities. Water doesn’t stop at municipal boundaries, and responsible treatment ensures that growth in St. Thomas does not place a burden on neighbours further along the watershed. It reflects a commitment to shared responsibility and regional stewardship. Taken together, these protections form a system built not just for today, but for the future. Wastewater management supports the St. Thomas that continues to take shape — a city growing in population, opportunity, and complexity, while remaining grounded in environmental care and public well-being.  Bottom Line: Protecting What Flows Beneath our City Wastewater management in Ontario — and in St. Thomas — is a highly regulated, expertly managed process designed to keep people safe and the environment healthy. It is built on layers of protection: thoughtful engineering, advanced treatment technologies, continuous monitoring, and clear accountability at every stage of the system. Through carefully designed infrastructure, real-time oversight, and long-term planning, the City ensures that every litre of wastewater is treated with care before it returns to the natural world. What flows beneath our streets is not left to chance — it is measured, managed, and guided by standards meant to protect both today’s community and tomorrow’s. This work makes responsible growth possible. It allows St. Thomas to welcome new homes, new businesses, and new opportunities while safeguarding waterways, ecosystems, and downstream communities. It ensures that industrial development and residential expansion move forward alongside environmental stewardship, not at its expense. In the end, wastewater management is about more than pipes and treatment plants. It is about trust — trust that the systems in place are protecting public health, preserving natural resources, and laying the groundwork for a resilient, sustainable future. It is one of the quiet ways St. Thomas ensures that as the city grows, it does so responsibly, thoughtfully, and with care for all who live downstream — including generations yet to come.
1 Comment
Mike Intven
1/14/2026 05:56:29 pm
Hi Sarah, could I get 2 printed copies of this newsletter, ‘Wastewater Management In St Thomas? My address is Mike and Margaret Intven, 41819 Fulton Bridge Line, St Thomas, ON N5P 3S9 Leave a Reply. |
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