Work

Expansion of Mechanical Biological Residual Treatment Plant with Fermentation Stage for Press Water from Organic Fractions Involving a Screw Press

Year: 2025

Type: article

Abstract: A three-year optimization study was conducted at a mechanical biological treatment (MBT) plant using a screw press to extract organic fractions from mechanically separated fine fractions (MSFF). The study aimed to optimize key operating parameters for the employed screw press (SP) such as pressure, liquid-to-MSFF, feeding quantity per hour, and press basket mesh size to enhance volatile solids and biogas recovery in the generated press water (PW) for anaerobic digestion (AD). Experiments were performed at the full-scale MBT facility to evaluate the efficiency of screw press extraction with other pretreatment methods like press extrusion, wet pulping, and hydrothermal treatment. The results indicated that hydrolysis of the organic fractions in MSFF was the most important factor for improving organic extraction from the MSFF to press water for fermentation. The optimal hydrolysis efficiency was achieved with a digestate and process water-to-MSFF of approximately 1,000 l/ton, with a feeding rate between 8.8 and 14 tons per hour. Increasing pressure from 2.5 to 4.0 bar had minimal impact on press water properties or biogas production, regardless of the press basket size. The highest volatile solids (29%) and biogas (50%) recovery occurred at 4.0 bar pressure with a 1,000 L/ton liquid-to-MSFF. Further improvements could be achieved with longer mixing times before pressing. These findings demonstrate the technical feasibility of the pressing system for preparing an appropriate substrate for the fermentation process and underscore the potential for optimizing the system. However, further research is required to assess the cost-benefit balance.

Source: Recycling

DOI: 10.3390/recycling10040141

Authors: Rzgar Bewani, Abdallah Nassour, Thomas Böning, Jan Sprafke, Michael Nelles

Institutions: University of Rostock, Deutsches Biomasseforschungszentrum

Language: English

Topic: Anaerobic Digestion and Biogas Production

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Affordable and clean energy, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $2,172