Suchergebnisse

The application of partial nitritation and anammox processes (PN/A) to remove nitrogen can improve the energy efficiency of wastewater treatment plants (WWTPs) as well as diminish their operational costs. However, there are still several limitations that are preventing the widespread application of PN/A processes in urban WWTPs such as: (a) the loss of performance stability of the PN/A units operated at the sludge line, when the sludge is thermally pretreated to increase biogas production; (b) the proliferation of nitrite-oxidizing bacteria (NOB) in the mainstream; and (c) the maintenance of a suitable effluent quality in the mainstream. In this work, different operational strategies to overcome these limitations were modelled and analyzed. In WWTPs whose sludge is thermically hydrolyzed, the implementation of an anerobic treatment before the PN/A unit is the best alternative, from an economic point of view, to maintain the stable performance of this unit. In order to apply the PN/A process in the mainstream, the growth of ammonia-oxidizing bacteria (AOB) should be promoted in the sludge line by supplying extra sludge to the anaerobic digesters. The AOB generated would be applied to the water line to partially oxidize ammonia, and the anammox process would then be carried out. Excess nitrate generated by anammox bacteria and/or NOB can be removed by recycling a fraction of the WWTP effluent to the biological reactor to promote its denitrification ; This research was funded by the Chilean Government through the Projects ANID/FONDECYT/1200850 and CRHIAM Centre grant number ANID/FONDAP/15130015. FCC Aqualia, S.A. as coordinator of the LIFE ZERO WASTE WATER consortium would like to thank the European Commission for its support through LIFE financial instrument LIFE19ENV/ES/000631 ; SI

Polyhydroxyalkanoates (PHA) are biodegradable polymers that can be intracellularly produced by microorganisms valorizing organic-rich wastes. In the present study, a PHA production system was fed with mussel cooker wastewater after acidogenic fermentation. Besides low pH (4.0 ± 0.3) and high salt (21.7 ± 2.9 g NaCl/L) concentrations, this wastewater also contained nitrogen concentrations (0.8 ± 0.1 g N/L), which were previously reported to be a challenge to the PHA accumulating bacteria enrichment. Bacteria with a PHA storage capacity were selected in an enrichment sequencing batch reactor (SBR) after 60 days of operation. The enriched mixed microbial culture (MMC) was mainly formed by microorganisms from phylum Bacteroidetes, and genera Azoarcus, Comamonas and Thauera from phylum Proteobacteria. The MMC was able to accumulate up to 25 wt% of PHA that was mainly limited by the wastewater nitrogen content, which promoted biomass growth instead of PHA accumulation. Indeed, when the presence of nutrient was limited, PHA stored in the accumulation reactor increased to up to 40.9 wt%. This work demonstrated the feasibility of the enrichment of a MMC with a PHA storage ability valorizing the fish-canning industrial wastewater at low pH, which is generally difficult to treat in wastewater treatment plants ; This research was funded by the Spanish Government (AEI) through the FISHPOL (CTQ2014-55021-R) and TREASURE (CTQ2017-83225-C2-1-R) projects. The authors belong to the Galician Competitive Research Group GRC ED431C 2017/29 and to the CRETUS Strategic Partnership (ED431E 2018/01). All these programs are co-funded by the FEDER (EU) ; SI

Polyhydroxyalkanoates (PHA) are biodegradable polymers that can be intracellularly produced by microorganisms valorizing organic-rich wastes. In the present study, a PHA production system was fed with mussel cooker wastewater after acidogenic fermentation. Besides low pH (4.0 ± 0.3) and high salt (21.7 ± 2.9 g NaCl/L) concentrations, this wastewater also contained nitrogen concentrations (0.8 ± 0.1 g N/L), which were previously reported to be a challenge to the PHA accumulating bacteria enrichment. Bacteria with a PHA storage capacity were selected in an enrichment sequencing batch reactor (SBR) after 60 days of operation. The enriched mixed microbial culture (MMC) was mainly formed by microorganisms from phylum Bacteroidetes, and genera Azoarcus, Comamonas and Thauera from phylum Proteobacteria. The MMC was able to accumulate up to 25 wt% of PHA that was mainly limited by the wastewater nitrogen content, which promoted biomass growth instead of PHA accumulation. Indeed, when the presence of nutrient was limited, PHA stored in the accumulation reactor increased to up to 40.9 wt%. This work demonstrated the feasibility of the enrichment of a MMC with a PHA storage ability valorizing the fish-canning industrial wastewater at low pH, which is generally difficult to treat in wastewater treatment plants ; This research was funded by the Spanish Government (AEI) through the FISHPOL (CTQ2014-55021-R) and TREASURE (CTQ2017-83225-C2-1-R) projects. The authors belong to the Galician Competitive Research Group GRC ED431C 2017/29 and to the CRETUS Strategic Partnership (ED431E 2018/01). All these programs are co-funded by the FEDER (EU) ; SI

In Chile, small wastewater treatment plants (WWTPs) (treatment capacity of less than 4,800 m3/d) are normally not designed with consideration for the potential valorization of generated sludge. For this reason, they are generally operated at high solids residence times (SRT) (15 d) to promote the decay of biomass, promoting less sludge production and reducing the costs associated with biomass management. Operation at high SRT implies the need for a larger activated sludge system, increasing capital costs. The implementation of a sludge-disintegration unit by ozonation in future WWTPs could enable operation at an SRT of 3 d, with low sludge generation. In this work, we evaluate how the implementation of a sludge-ozonation system in small WWTPs (200–4000 m3/d) would affect treatment costs. Four scenarios were studied: (1) a current WWTP operated at an SRT of 15 d, without a sludge ozonation system; (2) a WWTP operated at an SRT of 15 d, with a sludge-ozonation system that would achieve zero sludge production; (3) a WWTP operated at an SRT of 3 d, with a sludge-ozonation system that would provide the same sludge production as scenario 1; (4) a WWTP operated at an SRT of 15 d, with a sludge-ozonation system that would achieve zero sludge production. Economic analysis shows that the treatment costs for scenarios 1 and 2 are similar, while a reduction in cost of up to 47% is obtained for scenarios 3 and 4 ; This research was funded by the Chilean Government through the Projects ANID/FONDECYT/1200850 and CRHIAM Centre grant number ANID/FONDAP/15130015, by the Spanish Government through TREASURE [CTQ2017-83225-C2-1-R] and by the European Commission LIFE ZERO WASTE WATER [LIFE19ENV/ES/000631] projects. The authors from Universidade de Santiago de Compostela belong to CRETUS Strategic Partnership [ED431E 2018/01] and the Galician Competitive Research Group [GRC ED431C-2021/37]. All the Spanish programs are co-funded by FEDER (EU) ; SI

This is the peer-reviewed version of the following article: Fra-Vázquez, A. , Pedrouso, A. , Palmeiro-Sánchez, T. , Moralejo-Gárate, H. and Mosquera-Corral, A. (2018), Feasible microbial accumulation of triacylglycerides from crude glycerol. J. Chem. Technol. Biotechnol, 93: 2644-2651, which has been published in final form at https://doi.org/10.1002/jctb.5618. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions ; BACKGROUND: Crude glycerol, a by-product of the biodiesel production industry, was used to produce intracellular storage polymers for waste valorization. The enrichment of a mixed microbial culture (MMC) in microorganisms with the ability to accumulate intracellular polymers was performed in a sequencing batch reactor (SBR) submitted to feast–famine conditions. The effect of different carbon sources in the accumulation of biopolymers was investigated. RESULTS: A MMC enriched in yeast and bacteria was obtained using crude glycerol as feedstock. Accumulation experiments performedwith crude glycerol, synthetic glycerol and synthetic methanol showed the feasibility of theMMCto producedifferent biopolymers. Triacylglyceride (TAG) accumulation up to 46wt% in yeast cellswas promoted by the presence of residual lipids in crude glycerol. However, bacteria fromclass Betaproteobacteria used glycerol mainly to accumulate 28wt% of polyglucose (PG) andmethanol as carbon source for cell growth. CONCLUSIONS: Aswaste valorization, a possible advantage which comes out of the present study is the use of open, non-sterile and non-defined systems to produce TAGs. These TAGs can potentially re-enter the biodiesel production process helping on the maximisation of the feedstock used in this process ; This research was supported by the Spanish Government (AEI) through FISHPOL (CTQ2014–55021-R) and GRANDSEA (CTM2014–55397-JIN) projects. The authors belong to the Galician Competitive Research Group GRC ED431C 2017/29 and to the CRETUS Strategic ...

The main bottleneck to maintain the long term stability of the partial nitritation-anammox processes, especially those operated at low temperatures and nitrogen concentrations is the undesirable development of nitrite oxidizing bacteria (NOB). When this occurs, the punctual addition of compounds with the capacity to specifically inhibit NOB without affecting the process efficiency might be of interest. Sodium azide (NaN3) is an already known NOB inhibitor which at low concentrations does not significantly affect the ammonia oxidizing bacteria (AOB) activity. However, studies about its influence on anammox bacteria are unavailable. For this reason the objective of the present study was to evaluate the effect of NaN3 on the anammox activity. Three different types of anammox biomass were used: granular biomass comprising AOB and anammox bacteria (G1), anammox enriched granules (G2) and previous anammox granules disaggregated (F1). No inhibitory effect of NaN3 was measured on G1 sludge however the anammox activity decreased in the case of G2 and F1. Granular biomass activity was less affected (IC50 90 mg/L, G2) than flocculent one (IC50 5 mg/L, F1). Summing up not only the granular structure protects the anammox bacteria from the NaN3 inhibitory effect but also the AOB act as a barrier decreasing the inhibition ; The authors want to thank the Pioneer_STP (ID 199) project funded by the WaterWorks2014 Cofunded Call (Water JPI/Horizon 2020). This work was also funded by the Spanish Government through FISHPOL (CTQ2014-55021-R) and GRANDSEA (CTM2014-55397-JIN) projects co-funded by FEDER. The authors from the USC belong to CRETUS (AGRUP2015/02) and the Galician Competitive Research Group (GRC 2013-032), programs co-funded by FEDER. The authors want to thank FCC Aqualia for the ELAN® biomass samples ; SI

A single stage partial nitritation and anammox granular pilot scale reactor (600 L) was operated to treat primary settled sewage in an urban wastewater treatment plant. The fed wastewater contained low total nitrogen concentrations of 6–25 mg TN/L and the system operated without temperature control ranging from 18 to 12 °C. A control strategy, based on the pH value, was applied to stop the aeration supply. The pH set-point was fixed at 6.0 and allowed obtaining a total nitrogen removal efficiency approximately of 50% treating a load of 67 mg TN/(L·d) without the addition of any chemicals. Although nitrite oxidizing bacteria were present in the inoculated sludge, when the pH-based control was implemented (day 30) the ammonium oxidation was favored compared to the nitrite oxidation activity. Then, the system operated stable the rest of the operational period (days 30–94) despite the presence of organic matter in the wastewater and the high variability of nitrogen load and temperature during the operation. Nitrogen was autotrophically removed accomplishing the stringent discharge limits (10 mg TN/L) and nitrate concentrations in the effluent lower than 3 mg NO3−-N/L. Both biomass concentration and granules size increased during the operational period indicating the growth of the biomass inside the reactor and therefore the potential treatment capacity. ; Authors want to thank the Pioneer_STP (ID 199) project funded by the WaterWorks2014 Cofunded Call (Water JPI/Horizon 2020). This work was also funded by the Spanish Government through FISHPOL (CTQ2014-55021-R) and GRANDSEA (CTM2014-55397-JIN) projects and by Galician Government by the MEDRAR (IN852A 2016) project. The authors from the USC belong to CRETUS (AGRUP2015/02) and the Galician Competitive Research Group (GRC ED431C 2017/29). All these programs are co-funded by FEDER. This work was as well funded by the Chilean Government through the Project FONDECYT 1150285 and CONICYT/FONDAP/15130015 ; SI

Anaerobic digestion (AD) is commonly used for the stabilization of agro-food wastes and recovery of energy as methane. Since AD removes organic C but not nutrients (N and P), additional processes to remove them are usually applied to meet the stringent effluent criteria. However, in the past years, there was a shift from the removal to the recovery of nutrients as a result of increasing concerns regarding limited natural resources and the importance given to the sustainable treatment technologies. Recovering N and P from anaerobically pretreated agro-food wastes as easily transportable and marketable products has gained increasing importance to meet both regulatory requirements and increase revenue. For this reason, this review paper gives a critical comparison of the available and emerging technologies for N and P recovery from AD residues ; This work was funded by the Chilean Government through the project FONDECYT 1180650 and CONICYT/FONDAP/15130015 and by the Spanish Government through TREASURE (CTQ2017-83225-C2-1-R) and GRANDSEA (CTM2014-55397-JIN) projects ; SI

Anaerobic digestion (AD) is commonly used for the stabilization of agro-food wastes and recovery of energy as methane. Since AD removes organic C but not nutrients (N and P), additional processes to remove them are usually applied to meet the stringent effluent criteria. However, in the past years, there was a shift from the removal to the recovery of nutrients as a result of increasing concerns regarding limited natural resources and the importance given to the sustainable treatment technologies. Recovering N and P from anaerobically pretreated agro-food wastes as easily transportable and marketable products has gained increasing importance to meet both regulatory requirements and increase revenue. For this reason, this review paper gives a critical comparison of the available and emerging technologies for N and P recovery from AD residues ; This work was funded by the Chilean Government through the project FONDECYT 1180650 and CONICYT/FONDAP/15130015 and by the Spanish Government through TREASURE (CTQ2017-83225-C2-1-R) and GRANDSEA (CTM2014-55397-JIN) projects ; SI

Sludge is a by-product of municipal wastewater treatment plants (WWTPs) and its management contributes significantly to the operating costs. Large WWTPs usually have anaerobic sludge digesters to valorize sludge as methane and to reduce its mass. However, the low methane market price opens the possibility for generating other high value-added products from the organic matter in sludge, such as polyhydroxyalkanoates (PHAs). In this work, the economic feasibility of retrofitting two types of WWTPs to convert them into biofactories of crude PHAs was studied. Two cases were analyzed: (a) a large WWTP with anaerobic sludge digestion; and (b) a small WWTP where sludge is only dewatered. In a two-stage PHA-production system (biomass enrichment plus PHAs accumulation), the minimum PHAs cost would be 1.26 and 2.26 US$/kg PHA-crude for the large and small WWTPs, respectively. In a single-stage process, where a fraction of the secondary sludge (25%) is directly used to accumulate PHAs, the production costs would decrease by around 15.9% (small WWTPs) and 19.0% (large WWTPs), since capital costs associated with bioreactors decrease. Sensitivity analysis showed that the PHA/COD (Chemical Oxygen Demand) yield is the most crucial parameter affecting the production costs. The energy, methane, and sludge management prices also have an essential effect on the production costs, and their effect depends on the WWTP's size ; This research was funded by the Chilean Government through the Projects FONDECYT 1200850 and CRHIAM Centre grant number ANID/FONDAP/15130015. This research was also supported by the Spanish Government (AEI) through the TREASURE project (CTQ2017-83225-C2-1-R). Authors from USC belong to the Galician Competitive Research Group ED431C 2017/29. All these programs are co-funded by FEDER (EU) ; SI

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). With a progressive salt concentration increase for 150 days, the PN-AMX process was able to remove the 80% of the nitrogen at 7–9 g NaCl/L. The microbiological data indicated that NaCl and ammonia concentrations and temperature are important factors shaping PN-AMX communities. Thus, the NOB abundance (Nitrospira) decreases with the increase of the salt concentration, while heterotrophic denitrifiers are able to outcompete anammox after a peak of organic matter in the feeding ; This work was supported by the Spanish Government through GRANDSEA (CTM2014-55397-JIN) and FISHPOL (CTQ2014-55021-R) projects co-funded by FEDER, and the Chilean Government (CONICYT/FONDAP/15130015). The authors from the USC belong to CRETUS (AGRUP2015/02) and the Galician Competitive Research Group (GRC 2013-032), programs co-funded by FEDER ; SI