Fr / En / Sp

Municipal sludge drying

This ground-mounted thermosolar installation provides heat to a large municipal sludge dryer in Arizona, taking advantage of the region's abundant solar resources. Traditionally, municipal sludge is sent to landfills; however, this innovative system sterilizes the sludge using renewable energy, converting it into a valuable fertilizer. By harnessing concentrated solar thermal energy, the process exemplifies state-of-the-art waste treatment techniques, reducing environmental impact and promoting sustainability.

3
Pumping module

The pumping module contains the main pump, heat exchanger, monitoring instrumentation, and control panel. Its primary function is to regulate the circulation of fluid through the solar field while ensuring that the system operates within optimal performance parameters.
2
Solar dryer

The solar dryer consists of a greenhouse equipped with forced ventilation and a heated floor that circulates fluid warmed by the solar field. Wet sludge is introduced via an automated conveyor system, then periodically flipped and moved towards the greenhouse's outer end. By the end of the process, the sludge is both dried and sterilized, transforming it into a safe, usable fertilizer.
5
Heat storage

The installation is equipped with a large heat storage system consisting of a vertical water reservoir, which serves as a buffer to ensure the steady operation of the dryer.

1
S21 parabolic through solar field

The primary heating power of the installation is provided by a 1,600 m² solar field, consisting of 24 rows of Series 21 parabolic troughs.
4
Piping

The circulated water is transported through a steel pipe network, with one manifold supplying the rows from the eastern side and another manifold collecting the water on the western side.

The main components of a concentrated solar drying facility

1. Parabolic throughs
3. Pumping module
5. Storage tank
2. Solar dryer
4. Piping network

The importance of sludge drying in a modern municipal waste management systems

Sludge drying is a critical process in municipal waste management, primarily aimed at reducing the volume and weight of wastewater sludge, a byproduct of sewage treatment plants. The process involves the removal of water from the sludge, which helps in minimizing its disposal costs, as well as improving its handling, transportation, and storage.

In wastewater treatment plants, sewage is processed to remove solids, organic materials, and contaminants. However, the remaining sludge, often rich in moisture, presents both an environmental challenge and a logistical problem. Sludge drying addresses these challenges by using various methods such as thermal drying, solar drying, or mechanical dewatering. The main goal is to decrease the water content, thereby transforming the sludge into a more stable and less odorous material.

By reducing the moisture content, sludge drying offers several benefits. First, it significantly lowers the weight and volume of the waste, making it easier and more cost-effective to transport and dispose of. Second, the dried sludge can be further treated and converted into useful byproducts, such as fertilizers or fuel for energy generation, contributing to sustainable waste management practices. In some cases, dried sludge can even be utilized in land reclamation or as an additive in construction materials.

Sludge drying is also beneficial from an environmental perspective. It helps mitigate the pollution risks associated with untreated sludge, such as the release of harmful pathogens, odors, and greenhouse gases. By employing energy-efficient and eco-friendly drying technologies, municipalities can ensure that their waste management processes are both effective and sustainable.

Some views of a typical site

12