Towards the implementation of hydrothermal carbonization for nutrients, carbon, and energy recovery in centralized biogas plant treating sewage sludge.

In recent years, extensive experimental research on hydrothermal carbonization (HTC) of sewage sludge has been performed, to study the effects of process conditions on hydrochar characteristics and nutrient, carbon, and energy recovery from sewage sludge. To promote the implementation of HTC, this study assessed HTC (230 °C, 30 min) integration into an advanced centralized biogas plant by analyzing its theoretical effects on the fates of sewage sludge solids, nitrogen, phosphorus, and carbon. The study used the mass and nutrient flows and concentrations obtained from laboratory studies, and the studied biogas plant had an original layout that employed hygienization.

The effects of digestate pyrolysis liquid on the thermophilic anaerobic digestion of sewage sludge - Perspective for a centralized biogas plant using thermal hydrolysis pretreatment.

The use of pyrolysis process to valorize digestate from anaerobic digestion (AD) of municipal sewage sludge for biochar production was piloted in a central biogas plant. The pyrolysis also generates pyrolysis liquid with high organics and nutrient contents that currently has no value and requires treatment, which could potentially be done in AD. As the pyrolysis liquid may contain inhibitory compounds, we investigated the effects of adding the pyrolysis liquid on AD of sewage sludge and thermal hydrolysis pretreated sewage sludge (THSS) simulating the full-scale centralized biogas plant conditions.

Hydrothermal carbonization of pulp and paper industry wastewater treatment sludges - characterization and potential use of hydrochars and filtrates.

The pulp and paper industry's mixed sludge represents waste streams with few other means of disposal than incineration. Hydrothermal carbonization (HTC) could be advantageous for the sludge refinement into value-added products, thus complementing the concept of pulp and paper mills as biorefineries. Laboratory HTC was performed on mixed sludge (at 32% and 15% total solids) at temperatures of 210-250 °C for 30 or 120 min, and the characteristics of the HTC products were evaluated for their potential for energy, carbon, and nutrient recovery.

Microbial community assembly and dynamics in Granular, Fixed-Biofilm and planktonic microbiomes valorizing Long-Chain fatty acids at 20 °C.

Distinct microbial assemblages evolve in anaerobic digestion (AD) reactors to drive sequential conversions of organics to methane. The spatio-temporal development of three such assemblages (granules, biofilms, planktonic) derived from the same inoculum was studied in replicated bioreactors treating long-chain fatty acids (LCFA)-rich wastewater at 20 °C at hydraulic retention times (HRTs) of 12-72 h. We found granular, biofilm and planktonic assemblages differentiated by diversity, structure, and assembly mechanisms; demonstrating a spatial compartmentalisation of the microbiomes from the initial community reservoir.

Simulated acid mine drainage treatment in iron oxidizing ceramic membrane bioreactor with subsequent co-precipitation of iron and arsenic.

Acid mine drainage (AMD), generated in the active and abandoned mine sites, is characterized by low pH and high metal concentrations. One AMD treatment possibility is biologically oxidizing Fe followed by precipitation through pH control. As compared to autotrophic iron oxidizing microbial community, a microbial community enriched in the presence of organic nutrients was hypothesized to yield higher biomass during commissioning the bioreactor.

Hydrothermal carbonisation of mechanically dewatered digested sewage sludge-Energy and nutrient recovery in centralised biogas plant.

This study aimed to assess the role of hydrothermal carbonisation (HTC) in digestate processing in centralised biogas plants receiving dewatered sludge from regional wastewater treatment plants and producing biomethane and fertilisers. Chemically conditioned and mechanically dewatered sludge was used as such (total solids (TS) 25%) or as diluted (15% TS) with reject water in 30 min or 120 min HTC treatments at 210 °C, 230 °C or 250 °C, and the produced slurry was filtered to produce hydrochars and filtrates. The different hydrochars contributed to 20-55% of the original mass, 72-88% of the TS, 74-87% of the energy content, 71-92% of the carbon, above 86% of phosphorous and 38-64% of the nitrogen present in the original digestates.

Power production and microbial community composition in thermophilic acetate-fed up-flow and flow-through microbial fuel cells.

The microbial communities developed from a mixed-species culture in up-flow and flow-through configurations of thermophilic (55 °C) microbial fuel cells (MFCs), and their power production from acetate, were investigated. The up-flow MFC was operated for 202 days, obtaining an average power density of 0.13 W/m, and Tepidiphilus was the dominant transcriptionally-active microorganisms.