FAQs

While these technologies require an upfront investment to get up and running, they are designed to pay off significantly over time. Merrell Bros. systems improve operational efficiency, reduce costly maintenance and emergency cleanouts, and help facilities plan more accurately with predictable performance and lower downtime. By drying and stabilizing biosolids on-site, transportation costs drop dramatically — fewer loads, lighter material, and less fuel. In many cases, facilities can also generate revenue through fertilizer sales.

Odor control is a key design feature in every Merrell Bros. technology. Our Solar-Thermal Pasteurization and Double Drum Drying systems are fully enclosed to minimize odor release and include integrated biofiltration systems that capture and neutralize air from processing areas. Controlled airflow and temperature management prevent odor-causing gases from forming, while enclosed conveyors and covered storage bunkers contain material after treatment.

Once the biosolids are fully dried and pelletized, odors are virtually eliminated. The finished fertilizer pellets are clean, dry, and stable — making them safe to store, transport, and use without producing unpleasant smells.

Yes. Our team assists with the data, testing, and documentation needed for permitting, compliance verification, and Class A certification.

Absolutely. Our systems can be added to facilities with existing dewatering capabilities. They are flexible and modular, allowing easy integration into your current operations without major redesigns.

Class A biosolids meet the highest EPA standards for pathogen and vector reduction, making them safe for use in agriculture, landscaping, and public applications. This classification allows biosolids to be reused safely instead of being sent to landfills or incinerators.

Yes. Each system is designed to integrate seamlessly. The Solar-Thermal or Double Drum technologies handle the drying and sanitizing, and the Pelletization system finishes the process by forming the final pellet product. Together, they create a full, end-to-end biosolids management solution.

Merrell Bros. technologies help municipalities and industries safely manage and reuse biosolids — the byproduct of wastewater treatment. Our systems turn biosolids from a costly disposal problem into a marketable, Class A fertilizer that benefits farmers, communities, home owners, golf courses, businesses, and the environment.

Our systems lower hauling and disposal costs, reduce landfill use, and help meet regulatory standards. By turning biosolids into Class A fertilizer, communities can reduce waste, support local agriculture, and create new opportunities for resource recovery.

System size depends on plant capacity and the technology selected. The Solar-Thermal Pasteurization setup uses greenhouse structures and typically requires more footprint but minimal utility demand, while Double Drum Drying offers a more compact, mechanical option ideal for space-limited sites. Our engineering team custom-designs each system to fit available space and operational needs.

Both systems can operate continuously. The Double Drum Dryer runs as a continuous feed system, while the Solar-Thermal Pasteurization process uses a daily batch cycle that’s automated for consistency. Each system is designed for steady throughput and minimal operator input.

Merrell Bros. provides full training during installation and startup. Operators learn how to monitor system performance, perform light maintenance, and manage data reporting. The systems are built for simplicity, using automation and controls that make daily operation easy and reliable.

Yes. Both technologies are built to handle fluctuations in feed rate and material consistency. Automated controls adjust temperature, speed, and retention time to maintain uniform drying and pasteurization even when conditions change.

Installation timelines vary depending on project size and permitting requirements, but most systems can be fully operational within 6–18 months of design approval. Our team works closely with each client to streamline the process from start to finish.

Absolutely. Each technology is modular and can be scaled to match a small municipal facility or a large regional treatment plant. Systems can also be expanded later as capacity needs grow.

All Merrell Bros. systems feature PLC-based automation and real-time monitoring. Operators can track temperatures, feed rates, and output quality through intuitive dashboards, ensuring performance and compliance with Class A biosolids standards.

Routine maintenance is minimal compared to traditional dryers or incinerators. Tasks typically include visual inspections, cleaning air filters, lubricating moving parts, and verifying sensor calibration. Our team will provide maintenance, training, and ongoing support as needed.

Each system includes safety and bypass protocols to prevent damage or downtime. Redundant components and automatic shutdown sequences protect the equipment, and Merrell Bros. offers rapid-response service and spare parts support.

By removing moisture efficiently and maintaining steady temperatures, our systems reduce corrosion, clogging, and mechanical strain. This lowers unplanned maintenance and extends the life of your equipment.

Both the Solar-Thermal Pasteurization and Double Drum Drying systems meet or exceed EPA 40 CFR Part 503 requirements for Class A pathogen and vector attraction reduction. Continuous temperature monitoring and documentation ensure compliance.

Our processes produce significantly lower emissions than incineration and minimize odor through enclosed systems and biofiltration. This helps facilities maintain regulatory compliance and better community relations.

By reusing biosolids instead of landfilling or incinerating them, facilities lower greenhouse gas emissions, conserve landfill space, and recycle valuable nutrients back into the soil — creating a measurable environmental benefit.

The Pelletization system produces uniform, dust-free fertilizer pellets. Nutrient content can be tailored with additives or blended to meet a variety of needs.

Yes. Once dried and pelletized, the fertilizer is shelf-stable and can be safely stored for extended periods in covered facilities with minimal risk of odor or degradation.

In many cases, yes. Our technologies can handle similar organic materials, including anaerobic digestate, food waste slurry, and agricultural byproducts. Our engineers evaluate each material for compatibility.

Yes. We offer performance tracking and data analytics through integrated control systems. Clients can monitor throughput, energy use, and drying efficiency to optimize performance and costs.

Merrell Bros. provides comprehensive operator training, including on-site instruction, maintenance workshops, and refresher courses. Our support team is always available for troubleshooting and ongoing education.

Yes. Pilot testing is available for clients who want to validate performance before committing to full-scale deployment. Demonstrations can also be arranged at active facilities using Merrell Bros. technology.

Our experience spans operations, engineering, fabrication, transportation, and environmental services, giving us a 360° understanding of the biosolids industry. We don’t just design systems — we operate them every day.

Long-term scientific studies have repeatedly demonstrated that biosolids recycling is safe. Monitoring of biosolids, soils, water resources and plants continue to show benefits from recycling. These studies formed the basis for federal and state biosolids regulations. The application of organic matter from biosolids can improve the physical, chemical and biological properties of soil. Organic matter can reduce soil erosion, increase water-holding capacity, provide nutrients for plant growth, and provide food and energy for beneficial soil microorganisms. Land applying biosolids is a great method of recycling, and it provides an excellent nutrient source for crops. Land application not only provides the landowner with a product that is excellent for the soil, but is also saves valuable landfill space. Biosolids provide the soil with nitrogen, phosphorus, potassium, trace minerals, and other nutrients vital to the production of crops. In addition, there are strict guidelines that we must adhere to for Class B Biosolids, including setbacks from wells, streams, public buildings, and more.

As part of the Federal 503 Monitoring rules all biosolids that are to be land applied must first be tested for Heavy Metals. Almost everything in our world has some extremely small amount of metals in it. Even toothpaste has metals in it, but the big question is, “How much?” The Federal EPA, through very exhaustive research and testing, has determined the maximum allowable amount of certain metals that are allowed in biosolids. Before biosolids are received at our facilities, every source is tested and verified to assure that the material is well within these limits.

The Federal EPA 503 rules require that all biosolids must meet certain treatment levels to assure the public that the material is safe for land application. The method that is used to measure this is called Pathogen Reduction. This is used to determine how much treatment the biosolids have had and how many disease-causing organisms could be present in the biosolids. We use a verification method called Fecal Coliform. Disease-causing organism are everywhere in our world, even on our hands, which is why normal washing practices are encouraged for everyone. The question we must ask as it relates to biosolids is, “At what level are the disease-causing organisms low enough to not cause a potential threat to humans?” Prior to receiving biosolids at our facilities, all biosolids must be well below the maximum allowable limit to assure complete compliance with all State and Federal regulations.

Ted & Terry Merrell are the co-owners of Merrell Bros. Inc. They live in Kokomo, Indiana, and before the first biosolids center was ever constructed away from the base of operations, they installed a biosolids center very close to both owners’ personal residences. This was intentionally done so that the owners would be able to make sure that the biosolids center concept did not cause or disrupt the lives of area residents and or neighbors. Because of that concern, great care is taken to make sure that odors are not an issue. The Federal EPA also addresses this issue as it relates to what they call Vector Attraction Reduction. What this term means is the ability of some outside source such as a wild animal, rodent, or domestic pet to be able to walk out onto a field and step into the biosolids and then transfer it back to a human or child. The Federal government has listed several methods to use to satisfy this requirement. Two of the methods we utilize are approved by the EPA. These two methods are called incorporation and direct injection. Both of these methods cover the biosolids with soil so that it cannot be seen or smelled. Covering the biosolids with soil reduces the potential for odor and vector attraction.

The use of biosolids is regulated by the federal and state governments. It has a long history of safe use as an alternative fertilizer. No more biosolids based nutrients can be applied to a field than the crop being grown can take up. This limitation practically eliminates the potential for groundwater contamination. Conversely, there is no regulatory limit to the amount of commercial fertilizer that can be applied to a field, making the potential for groundwater contamination from commercial fertilizer is greater than from the proper use of biosolids. Under certain economic conditions, such as when the price of crop being grown is high, and commercial fertilizer cost are low, farmers may choose to apply excess fertilizer to assure maximum crop yields. The nutrients in the excess fertilizer can easily contaminate the groundwater on and downstream of the field. In addition, recycling biosolids to grow crops reduces the use of valuable landfill space which would have been to dispose of this waste product.

Land applying biosolids completes the nutrient recycling circle. The nutrient circle begins with the farmer harvesting a crop. Using corn as an example, the corn is either processed into food for humans or fed to animals which will become food to sustain human life. Some of the nutrients in food eaten by humans pass through our bodies into sewer systems of municipalities across the country. The sewer lines empty into waste water treatment plants, where the waste water is thoroughly cleaned, then released into streams. The solids which are removed in the waste water cleaning process contain valuable nutrients. If recycled as biosolids, these nutrients are used to fertilize the next crop. And as long as there is human life, the supply of biosolids is never-ending. The Environmentally friendly part of this recycling program is that it is a complete 100% recycling method that does not release any greenhouse gases or carbons and can perpetually go on forever without any byproduct.