Transforming wastewater treatment plants to sustainable biorefineries by developing VFA platform

Reference number
Coordinator Högskolan i Borås - Akademin för Textil Teknik och Ekonomi
Funding from Vinnova SEK 500 000
Project duration November 2018 - May 2019
Status Completed
Venture Circular and biobased economy
Call Circular and biobased economy

Purpose and goal

The aim was to investigate production of VFAs from sludge and food wastes to substitute the external carbon source in WWTPs. The goals (and results) were to: 1. Produce VFAs in an MBR from sludge/food waste to 400 mgVFAs/gVSS. (Achieved by 95%). 2. Determine economic feasibility of scaled-up MBR to produce VFAs as fossil-based carbon source replacement for denitrification. (It is economically and environmentally attractive) 3. Test nutrient-removal from wastewater using the bio-based VFAs. Due to time limitation, these tests could not be performed in this step and planned for stage 2.

Expected results and effects

From the membrane bioreactor experiments without pH control, sewage sludge produced a maximum 380 mgVFAs/gVSS. The techno-economic analysis revealed that substitution of fossil-based methanol with VFAs is economically and environmentally attractive.

Planned approach and implementation

Different batch essays where conducted to study the effect of thermal and alkali pretreatment, pH (5-12), and mixing sludge and food waste on VFA production and methane inhibition. Then, optimum conditions with no chemical addition, using separate sludge and food waste were applied to continuous MBR for over 3 months. Using the acquired results, techno-economic analysis on largescale application of an MBR for replacing bio-VFAs with methanol for denitrification process was performed.

External links

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