Thermophilic (55 °C) and hyper-thermophilic (70 °C) anaerobic digestion as novel treatment technologies for concentrated black water

Marinus J Moerland,Laura Castañares Pérez,Maria E Ruiz Velasco Sobrino,Paraschos Chatzopoulos,Brendo Meulman,Vinnie De Wilde,Grietje Zeeman,Cees J.N Buisman,Miriam H.A Van Eekert

doi:10.1016/j.biortech.2021.125705

Marinus J Moerland, Laura Castañares Pérez + Show 7 more

Open Access

https://doi.org/10.1016/j.biortech.2021.125705

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Journal: Biomass	Publication Date: Aug 4, 2021
Citations: 11	License type: cc-by

Affiliation: Wageningen University & Research

Abstract

Thermophilic and hyper-thermophilic anaerobic digestion (AD) are promising techniques for the treatment of concentrated black water (toilet fraction of domestic wastewater collected by low flush volume toilets; BW), recovery of nutrients and simultaneous pathogen removal for safe recovery and reuse of those nutrients. This study showed that thermophilic AD (55 °C) of concentrated BW reaches the same methanisation and COD removal as mesophilic anaerobic treatment of BW (conventional vacuum toilets) and kitchen waste while applying a higher loading rate (OLR) (2.5–4.0 kgCOD/m3/day). With a retention time of 8.7 days, and an OLR of >3 kgCOD/m3/day, COD removal of 70% and a methanisation of 62% (based on CODt) was achieved during thermophilic AD. Hyper-thermophilic (70 °C) reached lower levels of methanisation (38%). Start-up time of thermophilic AD was 12 days. And during thermophilic AD, a shift from acetoclastic methanogenesis towards syntrophic acetate oxidation was observed.

Highlights

The growing world population causes increasing pressure on the environment and on agriculture for food supply, and increases the de mand for nutrients as nitrogen (N), phosphorous (P) and potassium (K)
As was estimated by Cordell et al (2009), the amount of P excreted by humans equalled 21% of the annual P used as artificial fertilizer, in most countries current legislative restrictions, social acceptance and technological challenges prevent the utilization of these nutrients present in domestic waste streams
Legislative re strictions mainly concern the presence of pathogens and heavy metals in faecal matter (Collivignarelli et al, 2019; Harder et al, 2019; Zeeman et al, 2008), whereas technological challenges are mainly caused by dilute waste streams (Verstraete et al, 2009; Zeeman and KujawaRoeleveld, 2011), which are unfavourable for nutrient recovery and energy production through anaerobic digestion (AD)

Summary

Introduction

The growing world population causes increasing pressure on the environment and on agriculture for food supply, and increases the de mand for nutrients as nitrogen (N), phosphorous (P) and potassium (K). As was estimated by Cordell et al (2009), the amount of P excreted by humans equalled 21% of the annual P used as artificial fertilizer, in most countries current legislative restrictions, social acceptance and technological challenges prevent the utilization of these nutrients present in domestic waste streams. Legislative re strictions mainly concern the presence of pathogens and heavy metals in faecal matter (Collivignarelli et al, 2019; Harder et al, 2019; Zeeman et al, 2008), whereas technological challenges are mainly caused by dilute waste streams (Verstraete et al, 2009; Zeeman and KujawaRoeleveld, 2011), which are unfavourable for nutrient recovery and energy production through AD. Treatment methods for nutrients, water and energy recovery can be tailor-made for each stream (Hammes et al, 2000; Zeeman and Kujawa-Roeleveld, 2011; Zeeman et al, 2008)

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