Innovative Technological Approach for the Cyclic Nutrients Adsorption by Post-Digestion Sewage Sludge-Based Ash...

Area of Science:

• Environmental Engineering
• Materials Science
• Agricultural Science

Background:

• Municipal wastewater treatment generates significant sludge, posing disposal challenges.
• Circular Economy principles offer sustainable solutions for waste valorization.
• Biogas production from sludge is an established energy recovery method.

Purpose of the Study:

• To develop an innovative technological approach for sludge management aligned with Circular Economy principles.
• To investigate the potential of functionalized combustion by-products from treated sludge as agricultural soil amendments.
• To evaluate the efficacy of nanostructural additives in enhancing the adsorption properties of sludge-derived ash for nutrient recovery.

Main Methods:

• Cascade biotechnological thermal conversion of sewage sludge, digestate, and ash.
• Incineration of sludge ash with purposeful addition of nanostructural additives (halloysite, kaolinite).
• Laboratory-scale verification of ash adsorbent properties for agricultural nutrients (Na+, K+, NO3-, SO42-, PO43-, Cl-) using adsorption isotherm models.

Main Results:

• Functionalized combustion by-products show potential for agricultural applications.
• Sludge-derived ash with nanostructural additives effectively adsorbs key agricultural nutrients.
• Phosphate(V) ion adsorption significantly increased with kaolinite (61.24%) and halloysite (76.19%) additives.

Conclusions:

• The proposed approach offers an innovative conversion cycle for wastewater sludge within a Circular Economy framework.
• Functionalized ash, particularly with halloysite and kaolinite, demonstrates high potential as a nutrient adsorbent for agricultural soils.
• This technology enables energy production (biogas) and valuable resource recovery from wastewater sludge.