Biology subjects

Vlaeminck, S. E.

Publications and source records attributed to Vlaeminck, S. E..

5 recordsLinked to original sources

bioRxiv2025

Environmental impact of integrating decentralized urine treatment in the urban wastewater management system: A comparative life cycle assessment

As municipal wastewater treatment regulations become more stringent, integrating source-separated urine treatment into centralized urban wastewater management offers a hybrid solution. However, it is not clear how the environmental impacts of such hybrid systems compare to highly efficient centralized wastewater treatment plants (WWTPs) with low N2O emissions and electricity use. In this study, a consequential life cycle assessment was used to compare the environmental impact of three urine hybrid wastewater treatment systems - which combine decentralized urine treatment with a highly efficient central WWTP - to a centralized WWTP treating mixed wastewater (baseline). The studied urine treatment systems include partial nitrification & distillation, struvite precipitation & stripping/scrubbing, and partial nitritation/anammox. Additionally, the contribution of urine alkalinization to the overall impact was quantified. The results show that at least one hybrid scenario showed a lower environmental impact in 8 out of the 10 assessed impact categories. Global warming potential and marine eutrophication were found to be higher than the baseline. Additionally, it was identified that urine alkalinization increased the environmental impact of the treatment system in 7 out of the 10 impact categories. A Pareto frontier analysis was developed to guide decision makers on where hybrid solutions could be used as a strategy to reduce global warming impacts of conventional WWTPs. It was realized that using N2O emission factors of 75 WWTPs, 87% of centralized WWTPs had lower CO2 emissions compared to partial nitrification & distillation, and 91% compared to partial nitritation/anammox hybrid solutions. However, at energy demands of 1 kWh/PE and 2 kWh/PE, both hybrid solutions showed lower emissions than all the studied WWTPs. The study highlights the potential of hybrid wastewater treatment solutions to address specific environmental challenges in wastewater management and a strategy to reduce global warming impacts in WWTPs with high N2O emissions and electricity use. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/636102v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@c97256org.highwire.dtl.DTLVardef@171989dorg.highwire.dtl.DTLVardef@da8e02org.highwire.dtl.DTLVardef@a151da_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

ecology↗

bioRxiv2023

Resource-efficient nitrogen removal from source separated urine with partial nitritation/anammox in a membrane aerated biofilm reactor

Source separation and decentralized urine treatment can cut costs in centralized wastewater treatment by diverting 80% of the nitrogen load in sewage. One promising approach for nitrogen removal in this context is partial nitritation/anammox (PN/A), reducing the aeration demand by 67% and organics dosage by 100% compared to nitrification/denitrification. Whilst previous studies with suspended biomass have encountered stability issues during PN/A treatment of urine, a PN/A biofilm was hypothesized to be more resilient. Its use for urine treatment was pioneered here for maximum rates and efficiencies in the energy efficient membrane-aerated biofilm reactor (MABR). Nitrogen removal rates of 1.0 g N L-1 d-1 and removal efficiencies of 80-95% were achieved during a 335-day stable operation at 28{degrees}C on stabilized (pH>11), diluted urine (10%). A balance between N2 and NO3 - formation was observed whilst optimizing the supply of O2 and was rate limiting for the conversion towards N2. Short-term operation on less- and undiluted urine yielded N removal rates of 0.6-0.8 g N L-1 d-1 and removal efficiencies of 93% on 66% urine and 85% on undiluted urine. Metataxonomic analysis and fluorescence in-situ hybridization confirmed the presence of biofilms consisting of nitrifiers (Nitrosomonas, Nitrospira) at the membrane side and anammox bacteria ("Candidatus Brocadia") at the anoxic bulk side. The findings suggest that a biofilm approach to PN/A treatment of urine overcomes stability issues, and a PN/A-MABR has significant potential for resource efficient decentralized treatment. In human long-duration deep-space missions, this gravity-independent technology could produce N2 to compensate artificial atmosphere losses whilst facilitating water recovery from urine. [GRAPHICAL ABSTRACT, COLOR] O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=101 SRC="FIGDIR/small/572732v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1680b0corg.highwire.dtl.DTLVardef@1ad822dorg.highwire.dtl.DTLVardef@3d5c4borg.highwire.dtl.DTLVardef@764841_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2020

Purple bacteria as added-value protein ingredient in shrimp feed: Litopenaeus vannamei growth performance, and tolerance against Vibrio and ammonia stress

Purple non-sulfur bacteria (PNSB) biomass is an emerging alternative protein source, yet research of PNSB as added-value protein ingredient is limited. This research aimed to study the use of PNSB as protein source for shrimp and investigate the shrimps tolerance against Vibrio and ammonia stress. A 28-day shrimp feeding trial was performed with Rhodopseudomonas palustris, Rhodobacter capsulatus and a mixed PNSB culture. PNSB contained in feed (5-10% protein substitution) resulted in 5-26% higher individual weights, better feed conversions ratios (1.2-1.7) compared to commercial feed (1.7) and tolerance against ammonia. In parallel, the effect of PNSB on the growth of Vibrio pathogens was tested in vitro. The species Rps. palustris, Rb. capsulatus, Rb. sphaeroides, Rhodospirillum rubrum and Afifella marina suppressed the growth of Vibrio parahaemolyticus TW01 and V. campbellii LMG 21363. Overall, this study demonstrated the potential of PNSB as nutritious feed ingredient for shrimp. This can contribute to circular economy, as PNSB enable resource recovery from wastewater. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=76 SRC="FIGDIR/small/964007v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@13773acorg.highwire.dtl.DTLVardef@18b24e7org.highwire.dtl.DTLVardef@23df69org.highwire.dtl.DTLVardef@1208e93_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG HighlightsO_LIPurple non-sulfur bacteria (PNSB) enhance the growth performance of shrimp C_LIO_LIPNSB-fed shrimp has better feed conversion ratio, growth rate and weight gain C_LIO_LIShrimp fed with Rhodopseudomonas are more resistance against ammonia stress C_LIO_LIFreeze-dried and live PNSB inhibit Vibrio pathogens in vitro C_LI

bioengineering↗

bioRxiv2020

Control tools to selectively produce purple bacteria for microbial protein in raceway reactors

Purple non-sulfur bacteria (PNSB) show potential for microbial protein production on wastewater as animal feed. They offer good selectivity (i.e. uneven community with high abundance of one species) when grown anaerobically in the light. However, the cost of a closed anaerobic photobioreactor (PBR) is prohibitive for protein production. While open raceway reactors are cheaper, their feasibility to selectively grow PNSB is thus far unexplored. This study developed tools to boost PNSB abundance in the biomass of a raceway reactor fed with volatile fatty acids as carbon source. For oxygen availability as tool, not stirring in the night (i.e. reduced oxygen supply) elevated the PNSB abundance from 8% to 20%. For light availability as tool, a 24-h illumination increased the PNSB abundance from 8% to 31% compared to a 12-h light/12-h dark regime. A reactor run at 2-d sludge retention time at the highest surface-to-volume ratio (10 m2 m-3 increased light availability) showed productivities up to 0.2 g protein L-1 d-1 and the highest PNSB abundance (78%). The estimated production cost is {euro}1.9 kg-1 dry weight (vs. PBR {euro}11.4 kg-1 dry weight). This study pioneered in PNSB-based microbial protein production in raceways, yielding cost efficiency along with high selectivity when avoiding the combined availability of oxygen, COD and darkness. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/912980v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@c5e3borg.highwire.dtl.DTLVardef@1fe8d28org.highwire.dtl.DTLVardef@e5630borg.highwire.dtl.DTLVardef@1c99bf3_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2020

Enriching and aggregating purple non-sulfur bacteria in an anaerobic sequencing-batch photobioreactor for nutrient capture from wastewater

Purple non-sulfur bacteria (PNSB), a guild of anoxygenic photomixotrophic organisms, rise interest to capture nutrients from wastewater in mixed-culture bioprocesses. One challenge targets the aggregation of PNSB biomass through gravitational separation from the treated water to facilitate its retention and accumulation, while avoiding the need for membranes. We aimed to produce an enriched, concentrated, well-settling, nutrient-removing PNSB biomass using sequencing batch regimes (SBR) in an anaerobic photobioreactor. The stirred tank was fed with a synthetic influent mimicking loaded municipal wastewater (430-860 mg CODAc LInf-1, COD:N:P ratio of 100:36:4-100:11:2 m/m/m), operated at 30{degrees}C and pH 7, and continuously irradiated with infrared (IR) light (>700 nm) at 375 W m-2. After inoculation with activated sludge at 0.1 g VSS L-1, PNSB were rapidly enriched in a first batch of 24 h: the genus Rhodobacter reached 54% of amplicon sequencing read counts. SBR operations at volume exchange ratio of 50% with decreasing hydraulic retention times (48 to 16 h; 1 to 3 cycles d-1) and increasing volumetric organic loading rates (0.2 to 1.3 kg COD m-3 d-1) stimulated the aggregation (compact granules of 50-150 m), settling (sedimentation G-flux of 4.7 kg h-1 m-2), and accumulation (as high as 3.8 g VSS L-1) of biomass. The sludge retention time (SRT) increased freely from 2.5 to 11 d without controlled sludge wasting. Acetate, ammonium, and orthophosphate were removed simultaneously (up to 96% at a rate of 1.1 kg COD m-3 d-1, 77% at 113 g N m-3 d-1, and 73% at 15 g P m-3 d-1) with a COD:N:P assimilation ratio of 100:6.7:0.9 (m/m/m). Competition for substrate and photons occurred in the PNSB guild. SBR regime shifts sequentially selected for Rhodobacter (90%) under shorter SRT and non-limiting acetate concentrations during reaction phases, Rhodopseudomonas (70%) under longer SRT and acetate limitation, and Blastochloris (10%) under higher biomass concentrations. We highlighted the benefits of a PNSB-based SBR process for biomass accumulation and simultaneous nutrient capture at substantial rates, and its underlying microbial ecology. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=121 SRC="FIGDIR/small/899062v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@1f167bdorg.highwire.dtl.DTLVardef@1d1c1e2org.highwire.dtl.DTLVardef@fe591org.highwire.dtl.DTLVardef@1a8c4e3_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIPNSB were highly enriched (90%) in an anaerobic stirred-tank photobioreactor. C_LIO_LIThe mixed-culture SBR process fostered PNSB biomass aggregation and accumulation. C_LIO_LIPNSB sludge reached 3.8 g VSS L-1 and a sedimentation G-flux of 4.7 kg h-1 m-2. C_LIO_LIPNSB enabled a high simultaneous removal of COD (96%), N (77%), and P (73%). C_LIO_LIRhodobacter, Rhodopseudomonas, and Blastochloris competed for acetate and photons. C_LI

bioengineering↗