Understanding Low-Temperature Belt Drying: A Complete Guide

What is Low-Temperature Belt Drying?

A Smarter, Safer Way to Dry Biosolids

Low-temperature belt drying is an energy-efficient method for reducing the moisture content of biosolids (organic materials resulting from wastewater treatment) or sludge by gently removing water through evaporation.

How Does Low-Temperature Belt Drying Work?

Low-temperature belt drying works by evenly distributing the sludge on a slow-moving, perforated conveyor belt. Heated air, often recovered from low-grade thermal energy systems, is circulated through the material to evaporate the moisture as the sludge travels through the dryer. The result is a significantly drier, lighter, and more manageable end product that’s easier to transport, store, or repurpose.

High vs. Low-Temperature Belt Drying

Not all drying technologies are created equal when it comes to drying biosolids or industrial sludge. High-temperature and low-temperature drying systems both aim to reduce moisture content, but they use different approaches and have very different safety, energy, and operational profiles.

Low-temperature dryers are changing the game in biosolid drying technology, as they significantly lower safety risks and energy consumption. It’s a smarter long-term investment for facilities focused on sustainability, operational efficiency, and regulatory compliance.

	High Temperature Belt Dryer	Low Temperature Belt Dryer
Operating Temperature	300°F to 1200°F (150°C to 650°C)	120°F and 220°F (50°C to 105°C)
Energy Efficiency	Higher energy consumption due to the need for combustion-based heat or large-scale electric heating elements.	Energy Efficiency – It uses significantly less energy, especially when integrated with waste heat from existing systems.
Oders and Emission	Odor generation and volatile organic compound (VOC) emissions, which often require expensive odor control systems.	Minimal Odors and Emissions – The gentle drying process produces fewer odors and air pollutants, cutting down on the need for air treatment systems.
Maintenance Needs	Greater system complexity and maintenance needs, with more components exposed to extreme wear and tear.	Simpler Operation – Fewer moving parts and lower heat stress mean less maintenance and longer equipment life.
Cost Savings	None	Simpler Operation – Fewer moving parts and lower heat stress mean less maintenance and longer equipment life.

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Industries That See the Greatest ROI from Low-Temperature Drying

While many sectors can benefit from this low-temperature drying technology, three industries in particular stand to gain the most: municipal wastewater treatment, dairy farmers, and industrial manufacturing facilities.

1. Municipal Wastewater Treatment Facilities

Municipalities managing wastewater treatment plants face growing pressure to reduce disposal costs, meet increasingly stringent environmental standards, and find sustainable reuse options for biosolids. Low-temperature belt dryers are particularly well-suited for these facilities because they:

industrial-municipal-water-wastewater-sludge

Produce Class A biosolids that meet EPA 503 regulations, enabling safe land application or beneficial reuse as fertilizer.
Reduce sludge volume by up to 90%, dramatically lowering hauling and landfill costs.
Operate efficiently at lower temperatures, minimizing the risk of odor release and reducing fire hazards.
Integrate seamlessly into existing dewatering processes, making them ideal for facilities already using decanter centrifuges.

For municipalities, low-temperature belt dryers provide long-term cost savings, reduced environmental impact, and flexibility in how biosolids are handled or repurposed, making them the go-to solution for modern wastewater management.

2. Dairy Farm

Large-scale dairy operations produce significant volumes of manure and nutrient-rich wastewater that must be properly treated and disposed of. Low-temperature belt dryers offer dairy farmers several important benefits:

Dry and stabilize manure solids, making them easier to store, handle, and transport.
Enable the creation of value-added byproducts, such as dried bedding material or pelletized fertilizer.
Improve nutrient management practices by reducing phosphorus content and preventing runoff into nearby water sources.

Low-temperature drying systems support sustainable farming practices by turning waste into a reusable resource while minimizing environmental risk and regulatory burdens.

3. Steel Mills and Industrial Wastewater Producers

Industrial manufacturers—including steel mills, chemical plants, and food processors—often generate high-strength wastewater and sludge as part of their operations. Low-temperature belt dryers help these industries:

Safely and efficiently dry heavy metal-laden sludge, preparing it for disposal or incineration.
Reduce total waste volume, which lowers disposal costs and eases compliance with local landfill restrictions.
Operate in energy-conscious environments, particularly when paired with waste heat recovery from industrial processes.

By integrating low-temperature belt drying technology, these facilities can ensure safer, cleaner operations while supporting Environmental, Social, and Governance (ESG) goals and avoiding penalties related to waste management.

Want to see what ROI a low-temperature belt dryer could deliver for your facility? Our team can walk you through potential savings, system sizing, and long-term performance. Contact us today.

Installing and Operating a Low-Temperature Belt Dryer

Low-temperature belt dryers are typically designed to integrate seamlessly into existing dewatering systems. Most dryers are installed downstream of a dewatering decanter centrifuge, where they receive partially dewatered sludge or biosolids.

Because low-temperature dryers are modular by design, they can be customized to fit the footprint, throughput, and layout of any facility—making them ideal for both new construction and retrofits.

System Components

Simply put, the low-temperature belt dryer system typically consists of a feeding mechanism, a belt conveyor where the material is evenly distributed, an enclosed drying chamber with controlled airflow, and an automated discharge area for the dried product. Warm air flows through the material, slowly evaporating moisture without the risks associated with high heat.

Operational Standpoint

From an operational standpoint, low-temperature belt dryers are designed for reliability and ease of use. They feature automated controls, low-maintenance components, and remote monitoring options for performance tracking.

Operators can easily adjust parameters like belt speed, temperature, and airflow to accommodate changes in sludge volume or moisture content via a user-friendly HMI. Additionally, because these systems operate at significantly lower temperatures, they pose fewer safety concerns and require less oversight than traditional high-temperature drying systems.

DLT Dryer Back View

Maintaining and Servicing a Low-Temperature Belt Dryer

Proper maintenance is essential to keep a low-temperature belt dryer operating efficiently and safely over the long term. Since most belt dryers are tailor-made to fit specific operations, they should come with a maintenance manual as well as a manufacturer-supported service plan and guidance.

Routine maintenance for belt dryers generally involves:

Checking the belt for signs of damage
Verifying roller alignment
Lubricating key mechanical components
Making sure the belt tension is properly set

It’s also essential to examine electrical elements like motors and sensors to confirm they’re operating as intended. Keeping the belt dryer clean is also vital to avoid the accumulation of dust, debris, and other contaminants that can compromise drying performance and reduce the quality of the end product.

Looking for a trusted repair and maintenance team for your decanter centrifuge? Click here.

Centrisys/CNP’s DLT Low-Temperature Belt Dryer: Innovative Sludge Drying Technology

If you’re exploring whether low-temperature belt drying is the right fit for your operation, the Centrisys/CNP DLT Dryer offers a reliable, safe, and energy-efficient solution tailored for the demands of today’s municipal and industrial biosolids management.

What Sets the DLT Belt Dryer Apart?

While there are other low-temperature belt dryers on the market, the Centrisys/CNP DLT Dryer is engineered with several unique features that prioritize energy efficiency, operational safety, and system reliability.

Designed with input from real-world field experience and enhanced by thoughtful engineering, the DLT Dryer provides long-term performance benefits that other systems don’t offer.

Here's what makes the Centrisys/CNP DLT Series stand out:

Closed-Loop Heat Recuperation: Recycles heat from exhaust air to preheat incoming air, improving efficiency and eliminating the need for less reliable condensation systems.
Hot Water Heat Source: Uses hot water instead of burners or oil, reducing safety risks and offering a cleaner, more stable drying process.
Modular, Independent Drying Sections: Each section operates autonomously, allowing the system to keep running even if one part requires maintenance.
Built-in Safety Features: Includes optional CO monitoring and emergency cooling that automatically activates when thresholds are exceeded.
Low-Odor Design: Controlled airflow and odor treatment help minimize smell, ideal for facilities near populated areas.
Customized Footprint: Vast configuration ranging from one to six heat segments, allowing for a design that fits your operational needs.

With roots in biosolids management dating back to the 1980s, Centrisys/CNP has earned a reputation for engineering excellence, first with our industry-leading decanter centrifuges and now with our innovative DLT Low-Temperature Belt Dryer.

We put decades of hands-on experience, precision engineering, and customer-first thinking into every aspect of our belt drying technology.

Our commitment doesn’t stop at delivery. When you choose Centrisys/CNP, you gain a long-term partner. From installation support and operator training to service, maintenance, and beyond, we’re here to ensure your low-temperature belt dryer performs at its best, giving you the best return on your investment possible.