centrta international technologies
Wastewater Sludge Processing
Globally, modern societies continuously generate large volumes of liquid waste. Composting or incineration represent linear processes with no direct resource recovery. However, by changing the approach to processing, it becomes possible to create sustainable recycling loops.
Water is a valuable natural resource that should not be used solely for dilution or transport of pollutants. Liquid waste streams contain significant amounts of water, as well as contaminants that must be removed. The goal is the recovery and reuse of nutrients.
We regard wastewater not as waste, but as a source of resources. Through proper treatment, water is purified and returned to the hydrological cycle, while nutrients are transformed into products that can re-enter the economy—such as fertilizers, biofuels, or additives.
A key component of liquid waste is municipal sewage sludge. In addition to its high water content (>75%), it contains nitrogen (N), ammonium, phosphates (P₂O₅), and carbon (C), along with contaminants such as heavy metals.
Sludge Dewatering: A Critical Step
Sludge generated in wastewater treatment plants often needs to be transported for further processing. To make this feasible, it is mechanically dewatered at the source, reaching a solids content of about 25% TS (Total Solids). Although most of the material is water, transportation remains costly and environmentally burdensome.
Traditional management methods, such as agricultural application or incineration, face increasing restrictions. Therefore, alternative solutions are needed to enable full resource recovery and utilization.
Incineration, for example, makes nutrient and water recovery impossible, while the high moisture content of sludge requires significant energy input for evaporation.
Our Proposed Processes
RSR – Resource Separation and Recovery Process
The RSR process (Resource Recovery) offers a “zero-discharge” solution, aiming for complete recovery of resources from sewage sludge. Specifically, it recovers:
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Water
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Nitrogen
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Phosphorus
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Potassium
The process is safe, economically viable, and environmentally friendly. Emissions are non-hazardous and filtered before release into the atmosphere.
Implementing RSR in wastewater treatment facilities enables:
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Reduction of CO₂ emissions
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Cost savings on transport and disposal
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Reuse of valuable resources
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Compliance with phosphorus recovery regulations.
SDS – Sludge Drying System
The SDS process focuses on energy-efficient sludge drying. Compared to conventional methods:
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It consumes 90% less electricity
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Uses 50% less thermal energy
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Dries up to 90% of sludge at temperatures as low as 60°C
This allows the production of dry residue suitable for energy or industrial applications, offering significant value in the circular economy.