Integrating food waste management into urban wastewater treatment: Economic and environmental impacts.

Food waste is the main component of municipal solid waste (MSW) and its sustainable management is a global challenge. Co-treatment of food waste and urban wastewater in wastewater treatment plants (WWTPs) could be a plausible management strategy to reduce the MSW amount that is disposed in landfills, while converting its organic fraction into biogas in the WWTP. However, the increased organic load in the wastewater influent would impact the capital and operating costs of the WWTP, mainly due to the increase in sludge production.

Microalgae-bacterial biomass outperforms PN-anammox biomass for oxygen saving in continuous-flow granular reactors facing extremely low-strength freshwater aquaculture streams.

The dissolved oxygen (DO) concentration in water streams is one of the most important and critical quality parameters in aquaculture farms. The main objective of this study was to evaluate the potential of two Continuous Flow Granular Reactors, one based on Partial Nitrification-Anammox biomass (Aquammox CFGR) and the other on Microalgae-Bacteria biomass (AquaMab CFGR), for improving dissolved oxygen availability in the recirculation aquaculture systems (RAS). Both reactors treated the extremely low-strength effluents from a freshwater trout farm (1.

Structure of fungal communities in sequencing batch reactors operated at different salinities for the selection of triacylglyceride-producers from a fish-canning lipid-rich waste stream.

Oleaginous fungi natively accumulate large amounts of triacylglycerides (TAG), widely used as precursors for sustainable biodiesel production. However, little attention has been paid to the diversity and roles of fungal mixed microbial cultures (MMCs) in sequencing batch reactors (SBR). In this study, a lipid-rich stream produced in the fish-canning industry was used as a substrate in two laboratory-scale SBRs operated under the feast/famine (F/F) regime to enrich microorganisms with high TAG-storage ability, under two different concentrations of NaCl (SBR-N: 0.

Membrane Fouling Mitigation in MBR via the Feast-Famine Strategy to Enhance PHA Production by Activated Sludge.

Fouling is considered one of the main drawbacks of membrane bioreactor (MBR) technology. Among the main fouling agents, extracellular polymeric substances (EPS) are considered one of the most impactful since they cause the decrease of sludge filterability and decline of membrane flux in the long term. The present study investigated a biological strategy to reduce the membrane-fouling tendency in MBR systems.

Simplified engineering design towards a competitive lipid-rich effluents valorization.

Medium- and long-chain fatty acids and glycerol contained in the oily fraction of many food-industry effluents are excellent candidates to produce biobased high-value triacylglycerides (TAGs) and polyhydroxyalkanoates (PHAs). The typical process configuration for TAGs recovery from lipid-rich streams always includes two steps (culture enrichment plus storage compounds accumulation) whereas, for PHAs production, an additional pretreatment of the substrate for the obtainment of soluble volatile fatty acids (VFAs) is required. To simplify the process, substrate hydrolysis, culture enrichment, and accumulation (TAG and PHA storage) were coupled here in a single sequencing batch reactor (SBR) operated under the double growth limitation strategy (DGL) and fed in pulses with industrial waste fish oil during the whole feast phase.

Dynamics of PHA-Accumulating Bacterial Communities Fed with Lipid-Rich Liquid Effluents from Fish-Canning Industries.

The biosynthesis of polyhydroxyalkanoates (PHAs) from industrial wastes by mixed microbial cultures (MMCs) enriched in PHA-accumulating bacteria is a promising technology to replace petroleum-based plastics. However, the populations' dynamics in the PHA-accumulating MMCs are not well known. Therefore, the main objective of this study was to address the shifts in the size and structure of the bacterial communities in two lab-scale sequencing batch reactors (SBRs) fed with fish-canning effluents and operated under non-saline (SBR-N, 0.

Valorization of lipid-rich wastewaters: A theoretical analysis to tackle the competition between polyhydroxyalkanoate and triacylglyceride-storing populations.

The lipid fraction of the effluents generated in several food-processing activities can be transformed into polyhydroxyalkanoates (PHAs) and triacylglycerides (TAGs), through open culture biotechnologies. Although competition between storing and non-storing populations in mixed microbial cultures (MMCs) has been widely studied, the right selective environment allowing for the robust enrichment of a community when different types of accumulators coexist is still not clear. In this research, comprehensive metabolic analyses of PHA and TAG synthesis and degradation, and concomitant respiration of external carbon, were used to understand and explain the changes observed in a laboratory-scale bioreactor fed with the lipid-rich fraction (mainly oleic acid) of a wastewater stream produced in the fish-canning industry.

Wastewater Valorization: Practice around the World at Pilot- and Full-Scale.

Over the last few years, wastewater treatment plants (WWTPs) have been rebranded as water resource recovery facilities (WRRFs), which recognize the resource recovery potential that exists in wastewater streams. WRRFs contribute to a circular economy by not only producing clean water but by recovering valuable resources such as nutrients, energy, and other bio-based materials. To this aim, huge efforts in technological progress have been made to valorize sewage and sewage sludge, transforming them into valuable resources.

Monitoring morphological changes from activated sludge to aerobic granular sludge under distinct organic loading rates and increasing minimal imposed sludge settling velocities through quantitative image analysis.

Quantitative image analysis (QIA) was used for monitoring the morphology of activated sludge (AS) during a granulation process and, thus, to define and quantify, unequivocally, structural changes in microbial aggregates correlated with the sludge properties and granulation rates. Two sequencing batch reactors fed with acetate at organic loading rates of 1.1 ± 0.

Sequencing versus continuous granular sludge reactor for the treatment of freshwater aquaculture effluents.

Ammonium and nitrite levels in water are crucial for fish health preservation and growth maintenance in freshwater aquaculture farms, limiting water recirculation. The aim of the present work was the evaluation and comparison of two granular sludge reactors which were operated to treat freshwater aquaculture streams at laboratory-scale: an Aerobic Granular Sludge - Sequencing Batch Reactor (AGS-SBR) and a Continuous Flow Granular Reactor (CFGR). Both units were fed with a synthetic medium mimicking an aquaculture recycling water (1.

Strategies for the valorisation of a protein-rich saline waste stream into polyhydroxyalkanoates (PHA).

Saline Mussels Cooking Wastewater was valorised to produce PHA with Mixed Microbial Cultures (MMC). Due to the high protein content (1.8-5.

Assessment of an aerobic granular sludge system in the presence of pharmaceutically active compounds by quantitative image analysis and chemometric techniques.

In this study, a sequencing batch reactor (SBR) with aerobic granular sludge (AGS) was operated with synthetic wastewater containing environmental relevant concentrations of 17β-estradiol (E2), 17α-ethinylestradiol (EE2) and sulfamethoxazole (SMX). Despite the presence of the studied PhAC, the granular fraction clearly predominated (TSS/TSS ranging from 0.82 to 0.

A novel strategy for triacylglycerides and polyhydroxyalkanoates production using waste lipids.

Lipids are one of the main components of the organic matter present in the effluents of the food-processing industry. These waste streams can be biotransformed into valuable triacylglycerides (TAGs) and polyhydroxyalkanoates (PHAs), precursors of biofuels and biomaterials alternative to petroleum-based products. These compounds are yielded by mixed microbial cultures, and considering that both TAG and PHA accumulators may coexist within the community, it seems crucial to define those operational strategies that might control the selection of the dominant metabolic pathways (TAG or PHA accumulation).

Is the ammonia stripping pre-treatment suitable for the nitrogen removal via partial nitritation-anammox of OFMSW digestate?

Treating the organic fraction of municipal solid waste (OFMSW) can be performed by coupling the anaerobic digestion (AD) and partial nitritation-anammox (PN-AMX) processes for organic matter and nitrogen removal, respectively. Besides, an ammonia stripping (AS) step before the AD benefit the removal of organic matter. In the present study, the operation of two PN-AMX sequencing batch reactors with and without AS pre-treated OFMSW digestate (AS-SBR and nAS-SBR, respectively) was assessed.

Volatile fatty acid production from saline cooked mussel processing wastewater at low pH.

The production of VFA using as substrate the wastewater produced in a cooked mussel processing factory, containing large COD (13.7 ± 3.2 g COD/L), salt concentrations (21.

Optimization of an enriched mixed culture to increase PHA accumulation using industrial saline complex wastewater as a substrate.

Polyhydroxyalkanoates (PHA) appear as good candidates to substitute conventional petroleum-based plastics since they have similar properties but with the advantage of being biodegradable. Wastewater streams with high organic content are feasible substrates for PHA production resulting in an opportunity for waste recovery. One of the main challenges is the optimization of the selection of microorganisms with high PHA storage capacity.

Performance of partial nitritation-anammox processes at mainstream conditions in an IFAS system.

The partial nitritation-anammox processes implementation in the main line of wastewater treatment plants would lead them closer to the energy autarky. With this purpose, an integrated fixed film activated sludge (IFAS) reactor was operated at pilot scale. Efficient nitrogen removal (72 ± 11%) was achieved for anaerobically pre-treated municipal wastewater at low temperature (21 - 15 °C), with a nitrogen removal rate of 37 ± 3 g N/(m·d) at 15 °C.

Predicting Accumulation of Intermediate Compounds in Nitrification and Autotrophic Denitrification Processes: A Chemical Approach.

Nitrification and sulfur-based autotrophic denitrification processes can be used to remove ammonia from wastewater in an economical way. However, under certain operational conditions, these processes accumulate intermediate compounds, such as elemental sulphur, nitrite, and nitrous oxide, that are noxious for the environment. In order to predict the generation of these compounds, an analysis based on the Gibbs free energy of the possible reactions and on the oxidative capacity of the bulk liquid was done on case study systems.

Performance and microbial features of the partial nitritation-anammox process treating fish canning wastewater with variable salt concentrations.

The partial nitritation-anammox (PN-AMX) process applied to wastewaters with high NaCl concentration was studied until now using simulated media, without considering the effect of organic matter concentration and the shift in microbial populations. This research work presents results on the application of this process to the treatment of saline industrial wastewater. Obtained results indicated that the PN-AMX process has the capability to recover its initial activity after a sudden/acute salt inhibition event (up to 16 g NaCl/L).

Influence of biomass acclimation on the performance of a partial nitritation-anammox reactor treating industrial saline effluents.

The performance of the partial nitritation/anammox processes was evaluated for the treatment of fish canning effluents. A sequencing batch reactor (SBR) was fed with industrial wastewater, with variable salt and total ammonium nitrogen (TAN) concentrations in the range of 1.75-18.

Integration of the Anammox process to the rejection water and main stream lines of WWTPs.

Nowadays the application of Anammox based processes in the wastewater treatment plants has given a step forward. The new goal consists of removing the nitrogen present in the main stream of the WWTPs to improve their energetic efficiencies. This new approach aims to remove not only the nitrogen but also to provide a better use of the energy contained in the organic matter.