Severe postpartum hemorrhage and the risk of adverse maternal outcome: A comparative analysis of two population-based studies in France and the Netherlands.

Objectives: Among women with severe PPH (sPPH) in France and the Netherlands, we compared incidence of adverse maternal outcome (major obstetric hemorrhage (≥2.5L blood loss) and/or hysterectomy and/or mortality) by mode of delivery. Second, we compared use and timing of resuscitation and transfusion management, second-line uterotonics and uterine-sparing interventions (intra-uterine tamponade, compression sutures, vascular ligation, arterial embolization) by mode of delivery. Methods:  Secondary analysis of two population-based studies of women with sPPH in France and the Netherlands. Women were selected by a harmonized definition for sPPH: (total blood loss ≥ 1500 ml) AND (blood transfusion of ≥ 4 units packed red blood cells and/or multicomponent blood transfusion). Findings: Incidence of adverse maternal outcome after vaginal birth was 793/1002, 9.1 % in the Netherlands versus 88/214, 41.1 % in France and 259/342, 76.2% versus 160/270, 59.3% after cesarean. Hemostatic agents such as fibrinogen were administered less frequently (p < 0.001) in the Netherlands (vaginal birth: 83/1002, 8.3% versus 105/2014, 49.5% in France; cesarean: 47/342, 13.7% and 152/270, 55.6%). Second-line uterotonics were started significantly later after PPH-onset in the Netherlands than France (vaginal birth: 46 versus 25 min; cesarean: 45 versus 18 min). Uterine-sparing interventions were less frequently (p < 0.001) applied in the Netherlands after vaginal birth (394/1002,39.3 %, 134/214, 62.6%) and cesarean (133/342, 38.9 % and 155/270, 57.4%), all initiated later after onset of refractory PPH in the Netherlands. Interpretation: Incidence of adverse maternal outcome was higher among women with sPPH in the Netherlands than France regardless mode of birth. Possible explanatory mechanisms are earlier and more frequent use of second-line uterotonics and uterine-sparing interventions in France compared to the Netherlands.

Clinical profiles of placenta accreta spectrum: the PACCRETA population-based study.

OBJECTIVE: To describe and compare the characteristics of women with placenta accreta spectrum (PAS) and their pregnancy outcomes according to the presence of placenta praevia and a prior caesarean section. DESIGN: Prospective population-based study. SETTING: All 176 maternity hospitals of eight French regions. POPULATION: Two hundred and forty-nine women with PAS, from a source population of 520 114 deliveries. METHODS: Women with PAS were classified into two risk-profile groups, with or without the high-risk combination of placenta praevia (or an anterior low-lying placenta) and at least one prior caesarean. These two groups were described and compared. MAIN OUTCOME MEASURES: Population-based incidence of PAS, characteristics of women, pregnancies, deliveries and pregnancy outcomes. RESULTS: The PAS population-based incidence was 4.8/10 000 (95% CI 4.2-5.4/10 000). After exclusion of women lost to follow up from the analysis, the group with placenta praevia and a prior caesarean included 115 (48%) women and the group without this combination included 127 (52%). In the group with both factors, PAS was more often suspected antenatally (77% versus 17%; P < 0.001) and more often percreta (38% versus 5%; P < 0.001). This group also had more hysterectomies (53% versus 21%, P < 0.001) and higher rates of blood product transfusions, maternal complications, preterm births and neonatal intensive care unit admissions. Sensitivity analysis showed similar results after exclusion of women who delivered vaginally. CONCLUSION: More than half the cases of PAS occurred in women without the combination of placenta praevia and a prior caesarean delivery, and these women had better maternal and neonatal outcomes. We cannot completely rule out that some of the women who delivered vaginally had placental retention rather than PAS; however, we found similar results among women who delivered by caesarean. TWEETABLE ABSTRACT: Half the women with PAS do not have both placenta praevia and a prior caesarean delivery, and they have better maternal outcomes.

Gestational anaemia and severe acute maternal morbidity: a population-based study.

Anaemia is frequently diagnosed during pregnancy. However, there are few data regarding its incidence, and the association with severe maternal morbidity remains uncertain and potentially biased in high-resource countries. The purpose of this study was to explore the association between gestational anaemia and severe acute maternal morbidity during and after delivery. We performed a cohort-nested case-control analysis from the epidemiology of severe maternal mortality (EPIMOMS) prospective study conducted in six French regions (2012-2013, n = 182,309 deliveries). There were 1669 women with severe acute maternal morbidity during or after delivery, according to a standardised definition obtained by expert consensus. The control group were randomly selected among women without severe morbidity who delivered in the same health centres (n = 3234). We studied the association between gestational anaemia and severe acute maternal morbidity during or after delivery overall, by cause, and by mode of delivery, using multivariable logistic regression and multiple imputation. Gestational anaemia was significantly more frequent in women with severe acute maternal morbidity (25.3%) than in controls (16.3%), p < 0.001, and mostly mild in both groups. After adjustment for confounders, women with gestational anaemia were at increased risk of overall severe acute maternal morbidity during and after delivery (adjusted OR (95%CI) 1.8 (1.5-2.1)). This association was also found for severe postpartum haemorrhage (adjusted OR (95%CI) 1.7 (1.5-2.0)), even after omitting the transfusion criterion (adjusted OR (95%CI) 1.9 (1.6-2.3)), and for severe acute maternal morbidity secondary to causes other than haemorrhage or pregnancy-related hypertensive disorders (adjusted OR (95%CI) 2.7 (1.9-4.0)). These results highlight the importance of optimising the diagnosis and management of anaemia during pregnancy.

An economic evaluation of tranexamic acid to prevent postpartum haemorrhage in women with vaginal delivery: the randomised controlled TRAAP trial.

OBJECTIVE: To estimate the cost-effectiveness of tranexamic acid (TXA) use to prevent postpartum haemorrhage. DESIGN: A trial-based economic evaluation. SETTING: Fifteen French university maternity hospitals. POPULATION: Women enrolled in the TRAAP randomised controlled trial comparing TXA versus placebo in women with vaginal delivery. TRAAP failed to show a reduction in postpartum haemorrhage of at least 500 ml in the intervention arm but evidenced significant lower rates of secondary outcomes related to blood loss. METHODS & MAIN OUTCOME MEASURES: We estimated direct medical costs from within-trial hospital resources collected prospectively from the study report form. All resources were costed at their value to the hospital. We estimated incremental cost per incremental haemorrhage averted. RESULTS: Among the 4079 women in the TRAAP trial, data necessary to calculate costs were available for 3836 (94.0%). The average total costs in the TXA and control groups were €2278 ± 388 and €2288 ± 409 per woman, respectively (P = 0.79). In women with postpartum haemorrhage of at least 500 ml (trial primary endpoint), costs were €2359 ± 354 and €2409 ± 525 (P = 0.14); for provider-assessed clinically significant postpartum haemorrhage and postpartum haemorrhage of at least 1000 ml, costs were respectively €2316 ± 347 versus €2381 ± 521 (P = 0.22) and €2321 ± 318 versus €2411 ± 590 (P = 0.35) in the tranexamic and placebo groups, respectively. The probabilistic sensitivity analysis showed that the use of TXA had a 65-73% probability of saving costs and improving outcome. CONCLUSIONS: Our findings support the use of TXA, as both bleeding events and cost may be reduced three out of four times. TWEETABLE ABSTRACT: Tranexamic acid at vaginal delivery reduces both costs and bleeding events 3 times out of 4.

On-line monitoring of photosynthetic activity based on pH data to assess microalgae cultivation.

Microalgae performance of outdoor cultivation systems is influenced by environmental and operating dynamics. Monitoring and control systems are needed to maximise biomass productivity and nutrient recovery. The goal of this work was to corroborate that pH data could be used to monitor microalgae performance by means of data from an outdoor membrane photobioreactor (MPBR) plant. In this system, microalgae photosynthetic activity was favoured over other physical and biological processes, so that the pH data dynamics was theoretically related to the microalgae carbon uptake rate (CUR). Short- and long-term continuous operations were tested to corroborate the relationship between the first derivate of pH data dynamics (pH') and microalgae photosynthetic activity. Short-term operations showed a good correlation between gross pH' values and MPBR performance. An indicator of the maximum daily average microalgae activity was assessed by a combination of on-line pH' measurements obtained in the long-term and a microalgae growth kinetic model. Both indicators contributed to the development of advanced real-time monitoring and control systems to optimise microalgae cultivation technology.

Anaerobic membrane bioreactor (AnMBR) scale-up from laboratory to pilot-scale for microalgae and primary sludge co-digestion: Biological and filtration assessment.

This research work proposes the scale-up evaluation in terms of biological and filtration performance from laboratory to pilot-scale of an anaerobic membrane bioreactor (AnMBR) co-digesting raw microalgae and primary sludge. Best operating conditions for this scale-up were energetically and economically assessed based on laboratory results. Economic balance showed 3% higher annual costs when operating a reactor at 100 d solids retention time (SRT) compared to 70 d SRT. Energetic balance showed a 5.5-fold increase in heat demand working at thermophilic temperature comparing to mesophilic. The AnMBR operating conditions were set at 70 d SRT and 35 °C. The pilot-scale and lab-scale co-digesters performed similarly in terms of biogas production and system stability. 154 mLbiogas·d-1·L-1reactor were produced at pilot-scale, corresponding to methane yield of 215 mLCH4·gCODinf-1. AnMBR filtration at both laboratory and pilot-scale showed stability working at permeate fluxes of 4.2-5.8 L·m-2·h-1.

Plant-wide modelling in wastewater treatment: showcasing experiences using the Biological Nutrient Removal Model.

Plant-wide modelling can be considered an appropriate approach to represent the current complexity in water resource recovery facilities, reproducing all known phenomena in the different process units. Nonetheless, novel processes and new treatment schemes are still being developed and need to be fully incorporated in these models. This work presents a short chronological overview of some of the most relevant plant-wide models for wastewater treatment, as well as the authors' experience in plant-wide modelling using the general model BNRM (Biological Nutrient Removal Model), illustrating the key role of general models (also known as supermodels) in the field of wastewater treatment, both for engineering and research.

An integral approach to sludge handling in a WWTP operated for EBPR aiming phosphorus recovery: Simulation of alternatives, LCA and LCC analyses.

As phosphorus is a non-renewable resource mainly used to produce fertilizers and helps to provide food all over the world, the proper management of its reserves is a global concern since it is expected to become scarcer in the near future. In this work we assessed two different sludge line configurations aiming for P extraction and recovery before anaerobic digestion and compared them with the classical configuration. This study has been performed by simulation with the model BNRM2 integrated in the software package DESASS 7.1. Configuration 1 was based on the production of a PO4-enriched stream from sludge via elutriation in the primary thickeners, while Configuration 2 was based on the WASSTRIP® process and its PO4-enriched stream was mechanically obtained with dynamic thickeners. In both alternatives recovery was enhanced by promoting poly-phosphate (poly-P) extraction under anaerobic conditions, for which both configurations were fully evaluated in a full-scale WWTP. Both were also optimized to maximize phosphorus extraction. Their costs and life cycles were also analysed. The novelty of this research lies in the lack of literature about the integral evaluation of pre-anaerobic digestion P recovery from wastewaters. This study included a holistic approach and an optimization study of both alternatives plus their economic and environmental aspects. In Configuration 1, the PO4-P load in the recovery stream reached 43.1% of the total influent P load and reduced uncontrolled P-precipitation in the sludge line up to 52.9%. In Configuration 2, extraction was 48.2% of the influent P load and it reduced precipitation by up to 60.0%. Despite Configuration 1's lower phosphorus recovery efficiency, it had a 23.0% lower life cycle cost and a 14.2% lower global warming impact per hm3 of treated influent than Configuration 2. Configuration 1 also reduced the TAEC by 17.6% and global warming impact by 2.0% less than Configuration 0.

Nitrite inhibition of microalgae induced by the competition between microalgae and nitrifying bacteria.

Outdoor microalgae cultivation systems treating anaerobic membrane bioreactor (AnMBR) effluents usually present ammonium oxidising bacteria (AOB) competition with microalgae for ammonium uptake, which can cause nitrite accumulation. In literature, nitrite effects over microalgae have shown controversial results. The present study evaluates the nitrite inhibition role in a microalgae-nitrifying bacteria culture. For this purpose, pilot- and lab-scale assays were carried out. During the continuous outdoor operation of the membrane photobioreactor (MPBR) plant, biomass retention time (BRT) of 2 d favoured AOB activity, which caused nitrite accumulation. This nitrite was confirmed to inhibit microalgae performance. Specifically, continuous 5-d lab-scale assays showed a reduction in the nitrogen recovery efficiency by 32, 42 and 80% when nitrite concentration in the culture accounted for 5, 10 and 20 mg N·L-1, respectively. On the contrary, short 30-min exposure to nitrite showed no significant differences in the photosynthetic activity of microalgae under nitrite concentrations of 0, 5, 10 and 20 mg N·L-1. On the other hand, when the MPBR plant was operated at 2.5-d BRT, the nitrite concentration was reduced to negligible values due to increasing activity of microalgae and nitrite oxidising bacteria (NOB). This allowed obtaining maximum MPBR performance; i.e. nitrogen recovery rate (NRR) and biomass productivity of 19.7 ± 3.3 mg N·L-1·d-1 and 139 ± 35 mg VSS·L-1·d-1, respectively; while nitrification rate (NOxR) reached the lowest value (13.5 ± 3.4 mg N·L-1·d-1). Long BRT of 4.5 d favoured NOB growth, avoiding nitrite inhibition. However, it implied a decrease in microalgae growth and the accumulation of nitrate in the MPBR effluent. Hence, it seems that optimum BRT has to be within the range 2-4.5 d in order to favour microalgae growth with respect to AOB and NOB.

Improving membrane photobioreactor performance by reducing light path: operating conditions and key performance indicators.

Microalgae cultivation has been receiving increasing interest in wastewater remediation due to their ability to assimilate nutrients present in wastewater streams. In this respect, cultivating microalgae in membrane photobioreactors (MPBRs) allows decoupling the solid retention time (SRT) from the hydraulic retention time (HRT), which enables to increase the nutrient load to the photobioreactors (PBRs) while avoiding the wash out of the microalgae biomass. The reduction of the PBR light path from 25 to 10 cm increased the nitrogen and phosphorus recovery rates, microalgae biomass productivity and photosynthetic efficiency by 150, 103, 194 and 67%, respectively.The areal biomass productivity (aBP) also increased when the light path was reduced, reflecting the better use of light in the 10-cm MPBR plant. The capital and operating operational expenditures (CAPEX and OPEX) of the 10-cm MPBR plant were also reduced by 27 and 49%, respectively. Discharge limits were met when the 10-cm MPBR plant was operated at SRTs of 3-4.5 d and HRTs of 1.25-1.5 d. At these SRT/HRT ranges, the process could be operated without a high fouling propensity with gross permeate flux (J20) of 15 LMH and specific gas demand (SGDp) between 16 and 20 Nm3air·m-3permeate, which highlights the potential of membrane filtration in MPBRs. When the continuous operation of the MPBR plant was evaluated, an optical density of 680 nm (OD680) and soluble chemical oxygen demand (sCOD) were found to be good indicators of microalgae cell and algal organic matter (AOM) concentrations, while dissolved oxygen appeared to be directly related to MPBR performance. Nitrite and nitrate (NOx) concentration and the soluble chemical oxygen demand:volatile suspended solids ratio (sCOD:VSS) were used as indicators of nitrifying bacteria activity and the stress on the culture, respectively. These parameters were inversely related to nitrogen recovery rates and biomass productivity and could thus help to prevent possible culture deterioration.

Selecting the most suitable microalgae species to treat the effluent from an anaerobic membrane bioreactor.

Conventional treatments for nutrient removal in wastewater are shifting to Anaerobic Membrane Bioreactors, which produce a high-quality effluent with minimum sludge production. The effluent resulting contains high nitrogen and phosphorus load that can be eliminated by microalgae culture. The aim of this study is to evaluate the ammonium and phosphorus removal rate of different microalgae species in the effluent of an anaerobic treatment. For that, 4 different microalgae species have been tested (Chlamydomonas reinhardtii, Scenedesmus obliquus, Chlorella vulgaris and Monoraphidium braunii) in batch monoculture and mixed conditions. Results indicate that all species are able to eliminate both P and N in the medium with high removal rates. However, a slight interspecies competition may boost these removal rates and productivity values ensuring, the success of the process.

A population-based analysis of French transfusion practices for women experiencing severe postpartum hemorrhage.

BACKGROUND: Transfusion is a major therapy for severe postpartum hemorrhage but there are few population-based descriptions of practice. The objective of this retrospective French population-based study was to describe transfusion practices in women with severe postpartum hemorrhage and the compliance with guidelines. METHODS: Study data were sourced from a prior prospective population-based study of 182 309 deliveries in France between 2012 and 2013. Transfusion practices and compliance with French national guidelines were described for all women with severe postpartum hemorrhage who had been transfused with red blood cells. RESULTS: In 1495 women with severe postpartum hemorrhage (0.8% of all deliveries), 35.1% were not transfused, 50.0% were transfused during active bleeding and 14.9% exclusively after control of bleeding. Among 697 women with a hemoglobin level <7 g/dL, 21.4% were not transfused. In 747 women transfused during active bleeding, 68.8% also received fresh frozen plasma (fresh frozen plasma to red blood cell ratio between 0.5 and 1 in 80.4%). Forty-four percent received fibrinogen concentrate (including 37.4% with a plasma fibrinogen level >2 g/L) and 8.6% had a massive transfusion. Among 223 women transfused after bleeding was controlled, 5.4% received fresh frozen plasma and 13% had a hemoglobin level >7 g/dL. CONCLUSIONS: One in five women with severe postpartum hemorrhage and a low hemoglobin concentration did not receive blood transfusion, which does not comply with French national recommendations. Over-transfusion occurred in women in whom bleeding had been controlled. The use of tools to help clinicians with transfusion decision-making should be developed.

Unveiling microbial structures during raw microalgae digestion and co-digestion with primary sludge to produce biogas using semi-continuous AnMBR systems.

Methane production from microalgae can be enhanced through anaerobic co-digestion with carbon-rich substrates and thus mitigate the inhibition risk associated with its low C:N ratio. Acclimated microbial communities for microalgae disruption can be used as a source of natural enzymes in bioenergy production. However, co-substrates with a certain microbial diversity such as primary sludge might shift the microbial structure. Substrates were generated in a Water Resource Recovery Facility (WRRF) and combined as follows: Scenedesmus or Chlorella digestion and microalgae co-digestion with primary sludge. The study was performed using two lab-scale Anaerobic Membrane Bioreactors (AnMBR). During three years, different feedstocks scenarios for methane production were evaluated with a special focus on the microbial diversity of the AnMBR. 57% of the population was shared between the different feedstock scenarios, revealing the importance of Anaerolineaceae members besides Smithella and Methanosaeta genera. The addition of primary sludge enhanced the microbial diversity of the system during both Chlorella and Scenedesmus co-digestion and promoted different microbial structures. Aceticlastic methanogen Methanosaeta was dominant in all the feedstock scenarios. A more remarkable role of syntrophic fatty acid degraders (Smithella, Syntrophobacteraceae) was observed during co-digestion when only microalgae were digested. However, no significant changes were observed in the microbial composition during anaerobic microalgae digestion when feeding only Chlorella or Scenedesmus. This is the first work revealing the composition of complex communities for semi-continuous bioenergy production from WRRF streams. The stability and maintenance of a microbial core over-time in semi-continuous AnMBRs is here shown supporting their future application in full-scale systems for raw microalgae digestion or co-digestion.

Co-digestion of harvested microalgae and primary sludge in a mesophilic anaerobic membrane bioreactor (AnMBR): Methane potential and microbial diversity.

Anaerobic co-digestion of primary sludge and raw microalgae (Scenedesmus and Chlorella) was performed in a lab-scale semi-continuous anaerobic membrane bioreactor to assess the biological performance and identify the microbial community involved in the co-digestion process. The reactor was operated at 35 °C for 440 days, working at a solids retention time of 100 days. The system achieved 73% biodegradability and showed high stability in terms of pH and volatile fatty acids. An enriched microbial community was observed. Of the several phyla, Chloroflexi and Proteobacteria were the most abundant. Cellulose-degraders phyla (Bacteroidetes, Chloroflexi and Thermotogae) were detected. Syntrophic microorganisms played an important role in intermediate degradation, enhancing methane production, mainly carried out by Methanosaeta. A nutrient-rich effluent (400 mg NH4-N·L-1 and 29 mg PO4-P·L-1) and digestate (860 mg N·L-1 and 151 mg P·L-1) were obtained. The bio-nutrients released from anaerobic co-digestion could be reused for microalgae cultivation or agricultural applications.

Dataset to assess the shadow effect of an outdoor microalgae culture.

This data in brief (DIB) article is related to a Research article [1]. Microalgae biomass absorb the light photons that are supplied to the culture, reducing the light availability in the inner parts of the photobioreactors. This is known as self-shading or shadow effect. This effect has been widely studied in lab conditions, but information about self-shading in outdoor photobioreactors is scarce. How this shadow effect affects the light availability in an outdoor photobioreactor was evaluated. In addition, advantages and disadvantages of different artificial light sources which can overcome light limitation are described.

P-recovery in a pilot-scale struvite crystallisation reactor for source separated urine systems using seawater and magnesium chloride as magnesium sources.

Practical recovery of a non-renewable nutrient, such as phosphorus (P), is essential to support modern agriculture in the near future. The high P content of urine, makes it an attractive source for practicing the recovery of this crucial nutrient. This paper presents the experimental results at pilot-plant scale of struvite crystallisation from a source-separated urine stream using two different magnesium sources, namely magnesium chloride and seawater. The latter was chosen as sustainable option to perform P-recovery in coastal areas. Real seawater was used to assess in a more realistic way its efficiency to precipitate P as struvite, since its composition (with noticeable concentration of ions such as Ca2+, SO42-, Na+, …) could lead to the formation of impurities and other precipitates. 0.99 g of struvite was obtained per litre of urine irrespective of the operational conditions tested. In all tested conditions, precipitation efficiencies exceeded 90% and recovery efficiencies were higher than 87%, with an average struvite crystal size higher than 110 µm (and up to 320 µm, depending on the experimental conditions) in the harvested struvite samples. Almost pure struvite was obtained when MgCl2 was used as precipitant, while amorphous calcium phosphate and other impurities appeared in the precipitates using seawater as magnesium source. However, the lower settling velocity of the amorphous precipitates in comparison with the struvite precipitates suggests that their separation at industrial scale could be relatively straightforward.

Risk of severe maternal morbidity associated with in vitro fertilisation: a population-based study.

OBJECTIVE: To investigate the association between in vitro fertilisation IVF and severe maternal morbidity (SMM) and to explore the role of multiple pregnancy as an intermediate factor. DESIGN: Population-based cohort-nested case-control study. SETTING: Six French regions in 2012/13. POPULATION: Cases were 2540 women with SMM according to the EPIMOMS definition; controls were 3651 randomly selected women who gave birth without SMM. METHODS: Analysis of the associations between IVF and SMM with multivariable logistic regression models, differentiating IVF with autologous oocytes (IVF-AO) from IVF with oocyte donation (IVF-OD). The contribution of multiple pregnancy as an intermediate factor was assessed by path analysis. MAIN OUTCOME MEASURES: Severe maternal morbidity overall and SMM according to its main underlying causal condition and by severity (near misses). RESULTS: The risk of SMM was significantly higher in women with IVF (adjusted OR = 2.5, 95% CI 1.8-3.3). The risk of SMM was significantly higher with IVF-AO, for all-cause SMM (aOR = 2.0, 95% CI 1.5-2.7), for near misses (aOR = 1.9, 95% CI 1.3-2.8), and for intra/postpartum haemorrhages (aOR = 2.3, 95% CI 1.6-3.2). The risk of SMM was significantly higher with IVF-OD, for all-cause SMM (aOR = 18.6, 95% CI 4.4-78.5), for near misses (aOR = 18.1, 95% CI 4.0-82.3), for SMM due to hypertensive disorders (aOR = 16.7, 95% CI 3.3-85.4) and due to intra/postpartum haemorrhages (aOR = 18.0, 95% CI 4.2-77.8). Path-analysis estimated that 21.6% (95% CI 10.1-33.0) of the risk associated with IVF-OD was mediated by multiple pregnancy, and 49.6% (95% CI 24.0-75.1) of the SMM risk associated with IVF-AO. CONCLUSION: The risk of SMM is higher in IVF pregnancies after adjustment for confounders. Exploratory results suggest higher risks among women with IVF-OD; however, confidence intervals were wide, so this finding needs to be confirmed. A large part of the association between IVF-AO and SMM appears to be mediated by multiple pregnancy. TWEETABLE ABSTRACT: The risk of severe maternal morbidity is higher in IVF-conceived pregnancies than in pregnancies conceived by other means.

Resource recovery from sulphate-rich sewage through an innovative anaerobic-based water resource recovery facility (WRRF).

This research work proposes an innovative water resource recovery facility (WRRF) for the recovery of energy, nutrients and reclaimed water from sewage, which represents a promising approach towards enhanced circular economy scenarios. To this aim, anaerobic technology, microalgae cultivation, and membrane technology were combined in a dedicated platform. The proposed platform produces a high-quality solid- and coliform-free effluent that can be directly discharged to receiving water bodies identified as sensitive areas. Specifically, the content of organic matter, nitrogen and phosphorus in the effluent was 45 mg COD·L-1, 14.9 mg N·L-1 and 0.5 mg P·L-1, respectively. Harvested solar energy and carbon dioxide biofixation in the form of microalgae biomass allowed remarkable methane yields (399 STP L CH4·kg-1 CODinf) to be achieved, equivalent to theoretical electricity productions of around 0.52 kWh per m3 of wastewater entering the WRRF. Furthermore, 26.6% of total nitrogen influent load was recovered as ammonium sulphate, while nitrogen and phosphorus were recovered in the biosolids produced (650 ± 77 mg N·L-1 and 121.0 ± 7.2 mg P·L-1).

Real-time optimization of the key filtration parameters in an AnMBR: Urban wastewater mono-digestion vs. co-digestion with domestic food waste.

This study describes a model-based method for real-time optimization of the key filtration parameters in a submerged anaerobic membrane bioreactor (AnMBR) treating urban wastewater (UWW) and UWW mixed with domestic food waste (FW). The method consists of an initial screening to find out adequate filtration conditions and a real-time optimizer applied to a periodically calibrated filtration model for minimizing the operating costs. The initial screening consists of two statistical analyses: (1) Morris screening method to identify the key filtration parameters; (2) Monte Carlo method to establish suitable initial control inputs values. The operating filtration cost after implementing the control methodology was €0.047 per m3 (59.6% corresponding to energy costs) when treating UWW and €0.067 per m3 when adding FW due to higher fouling rates. However, FW increased the biogas productivities, reducing the total costs to €0.035 per m3. Average downtimes for reversible fouling removal of 0.4% and 1.6% were obtained, respectively. The results confirm the capability of the proposed control system for optimizing the AnMBR performance when treating both substrates.

Outdoor flat-panel membrane photobioreactor to treat the effluent of an anaerobic membrane bioreactor. Influence of operating, design, and environmental conditions.

As microalgae have the ability to simultaneously remove nutrients from wastewater streams while producing valuable biomass, microalgae-based wastewater treatment is a win-win strategy. Although recent advances have been made in this field in lab conditions, the transition to outdoor conditions on an industrial scale must be further investigated. In this work an outdoor pilot-scale membrane photobioreactor plant was operated for tertiary sewage treatment. The effects of different parameters on microalgae performance were studied including: temperature, light irradiance (solar and artificial irradiance), hydraulic retention time (HRT), biomass retention time (BRT), air sparging system and influent nutrient concentration. In addition the competition between microalgae and ammonium oxidising bacteria for ammonium was also evaluated. Maximum nitrogen and phosphorus removal rates of 12.5 ± 4.2 mgN·L-1·d-1 and 1.5 ± 0.4 mgP·L-1·d-1, respectively, were achieved at a BRT of 4.5 days and HRT of 2.5 days, while a maximum biomass productivity of 78 ± 13 mgVSS·L-1·d-1 (VSS: volatile suspended solids) was reached. While the results obtained so far are promising, they need to be improved to make the transition to industrial scale operations feasible.