Phosphorus and sulfur pollution from wastewater is driving serious environmental and economic problems. Excess phosphorus is the main driver of toxic algal blooms in lakes and rivers. It damages ecosystems, contaminates drinking water, and costs billions in cleanup and lost tourism. At the same time, sulfur in wastewater creates hydrogen sulfide gas, which is dangerous for workers, causes severe odor issues, and reduces the quality of renewable biogas. Today, most treatment plants rely on iron- or aluminum-based chemicals. But these are costly, corrosive, and increasingly difficult to justify as regulations tighten and sustainability goals rise.
Green Steel Environmental addresses these problems by replacing hazardous chemicals with processed steel slag, a byproduct of steel manufacturing. By upcycling existing industrial waste, the company reduces chemical use and lowers treatment costs by at least 20 percent. This circular solution turns one industry’s waste into another’s environmental advantage.
To better understand how their system works, we spoke to Jonathan Teaford, CEO of Green Steel Environmental. This article contains notable highlights from our entire conversation.
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This interview is part of our exclusive Scouted By GreyB series. Here, we speak with the founders of innovative startups to understand how their solutions address critical industry challenges and help ensure compliance with industry and government regulations. (Know more about startups scouted by GreyB!)
“Communities are trying to remove more phosphorus, but adding more chemicals just means polluting the system in a different way.”
Jonathan Teaford is the CEO and Co-Founder of Green Steel Environmental, a company focused on sustainable solutions for wastewater treatment. Since July 2023, he has led the company’s mission to replace hazardous chemicals with eco-friendly additives that remove pollutants like phosphate and sulfide, helping industries meet environmental regulations while minimizing ecological impact. With a business background that includes an MBA from Northwestern’s Kellogg School of Management, Teaford brings strategic leadership to a company at the forefront of green innovation.
From steel slag to clean rivers: a new approach to wastewater treatment
Green Steel Environmental is a clean technology company focused on wastewater treatment. The company uses processed steel slag, a byproduct of steel manufacturing, to remove phosphorus and sulfur from wastewater. Its solution replaces traditional chemical additives, helping wastewater plants reduce pollution, cut costs, improve safety, and support renewable energy production through cleaner biogas.
What problem were you trying to solve in wastewater treatment?
Jon: Communities around the world struggle to remove enough phosphorus and sulfur from wastewater. Phosphorus is the main driver of algae blooms in rivers and lakes, and even small amounts can cause significant ecological damage. Sulfur creates hydrogen sulfide gas, which smells terrible, is dangerous for workers, and contaminates renewable methane produced at treatment plants.
The challenge is that most plants rely on hazardous chemicals to do this job. Those chemicals work, but as plants push for stricter limits, they have to add more and more of them. At that point, you are trading nutrient pollution for chemical pollution, which creates new environmental and operational risks.
How does your technology work differently from traditional chemicals?
Jon: We use steel slag, a byproduct of steel mills. It turns out that steel slag has a chemical composition similar to that of iron-based wastewater chemicals. Instead of manufacturing new chemicals, we take this existing waste material, process it, and use it to bind phosphorus and sulfur inside the digester.
The material is added as a solid rather than a liquid, but it fits easily into existing plant operations. It removes phosphorus and sulfur, often more effectively than traditional chemicals, without the handling risks or corrosion problems they pose.
Where are you seeing the strongest demand for this solution?
Jon: Municipal wastewater plants are a major market for us, especially as phosphorus regulations become stricter. We also see strong demand from food and beverage manufacturers, particularly dairy processors, where wastewater is very high in phosphorus and sulfur. Large-scale agriculture is another key area.
Dairy, pig, and poultry operations often have to truck wastewater long distances because nearby land is already overloaded with phosphorus. Our solution helps reduce that burden. We also work with pulp and paper mills, where sulfur odors are a major issue.
How does your solution compare in performance and cost?
Jon: We have done extensive head-to-head testing against traditional chemicals. Our material can remove around 60 percent of phosphorus and up to 80 percent of sulfur, and with optimization, we can outperform chemicals in many cases. Cost is where it becomes very compelling.
Because our raw material is a low-value industrial waste, our delivered cost is typically at least 20 percent lower than that of chemicals. That combination of better performance, lower cost, and environmental benefit makes adoption much easier.
What concerns do customers raise before adopting your technology?
Jon: One of the biggest questions was whether our material would disrupt the dewatering process. Dewatering is expensive, and plants cannot afford problems there. We ran full-scale tests and found that our material improves dewatering compared to both untreated and chemically treated systems.
Another concern is environmental safety after use. We tested air emissions, water toxicity, landfill safety, and fertilizer use. The material passes all regulatory tests, shows extremely low heavy metals, and is safe for soil, water, and aquatic life.
What challenges did you face in getting your first customers?
Jon: Wastewater plants are naturally risk-averse. If something goes wrong, it becomes public very quickly, and nobody wants that. Many plants told us they loved the solution but wanted to be the second customer.
The challenge was finding that first plant willing to lead. Once we addressed performance, dewatering, and regulatory questions with solid data, we unlocked our first customer. With full-scale results coming soon, we expect adoption to accelerate.
How easy is it for a plant to install and use your system?
Jon: Installation is relatively simple. Our system uses a bulk bag unloader and can feed material directly or as a slurry. It takes up little space and integrates into existing processes. Compared to alternatives that cost tens of millions of dollars, our solution typically costs around $60–70k to implement. That makes it accessible even for smaller municipalities.
What are your plans for expansion moving forward?
Jon: Our focus is on scaling within wastewater treatment first, especially where phosphorus regulations are tightening. We are also expanding deeper into food processing, agriculture, and pulp and paper, where sulfur and phosphorus problems are especially costly. Once we have more full-scale operating data, we expect many of the plants watching us closely to move forward quickly. The demand is already there, and the environmental pressure is only increasing.
Meet our Interviewer – Shabaz Khan, Marketing Manager at GreyB
Shabaz Khan, Marketing Manager
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