Aerobic granular biomass systems: a challenge for a better wastewater treatment and sludge management

The present thesis is framed in the field of wastewater treatment by the application of the aerobic granular technology and the posterior treatment of the granular sludge generated by anaerobic digestion. The lower surface requirement and the lower sludge production of aerobic granular systems, in comparison with the conventional activated sludge ones, make it a suitable technology to treat industrial effluents. Therefore in this thesis the following aspects were studied: the treatment of an industrial effluent from a seafood plant to obtain aerobic granular biomass, the effect of residual levels of coagulant-flocculant reagents on the aerobic granular system, the cycle distribution on the performance of the granular reactors and the feasibility of the anaerobic digestion to treat the aerobic granular sludge generated

Bacterial inactivation, photoreactivation and dark repair post flow-through pulsed UV disinfection

Pulsed UV (PUV) technology is accepted commercially for disinfection within the food packaging industry, but has yet to be deployed by the water/wastewater sector. This is partly due to a lack of robust, independently validated data for submerged or flow-through treatment applications. This study evaluated the efficacy of PUV for water disinfection under flow-through conditions. Bacterial pathogens of interest in the food and water/wastewater sector, namely Escherichia coli, Staphylococcus aureus and Listeria innocua (surrogate for L. monocytogenes) were used to investigate the potential for photoreactivation and/or dark repair post PUV flow-through disinfection. A continuous-flow low-pressure UV was also analysed under similar experimental conditions. Bacterial inactivation via flow-through PUV was dependant on energy output with E. coli exhibiting greatest sensitivity to PUV treatment (5.3 log 10 inactivation after treatment at 1539 mJ/cm 2 - output in UV range < 300 nm); L. innocua exhibited the highest PUV resistance (3.0 log 10 inactivation after treatment at 1539 mJ/cm 2 – output in UV range < 300 nm) under similar treatment conditions. Greater photoreactivation occurred at lower PUV outputs for both S. aureus and E. coli after flow-through PUV treatment. Thus exposure of treated bacteria to natural light, immediately post flow-through PUV treatment, should be avoided to minimise photoreactivation. The LPUV demonstrated inactivation of all bacteria below the limit of detection (1 CFU/mL) and inhibited the occurrence of photoreactivation. This study highlights the importance of considering bacterial repair potential and the need for further development of PUV technology for such applicationsThe authors would like to acknowledge the Department of Agriculture, Food and the Marine of Ireland (Ref: 13-F-507) for funding this research. Dr. Val del Rio was supported by the Spanish Government (CTM2014-55397-JIN project co-funded by FEDER) and Xunta de Galicia postdoctoral fellowshipS

Treatment and Valorisation of Saline Wastewater: Principles and Practice

This book covers the principles and practices of processes and technologies applied for the treatment of saline wastewater with discharge and reuse purpose, and those applied for its valorisation. Saline wastewater was considered to present electrical conductivities over 2 mS/cm, which is the limit for crop irrigation. Saline wastewater management is described with respect to: Basics about salinity characterisation and environmental impact; Effects of salinity on the wastewater physical-chemical treatments; Effects of salinity on biological treatment processes; Valorisation of saline wastewater for energy and materials production; Technologies for saline wastewater treatment and salt recovery; Urban and industrial saline wastewater treatment. Treatment and Valorisation of Saline Wastewater includes two case studies evaluating the treatment of the effluents from a fish cannery and from a WWTP with seawater intrusions in the collecting system. This book is intended as a text reference book for post-graduate, PhD students and researchers interested in the effects of salinity on the wastewater treatment and valorisation processes. It also serves as a reference text for professionals working in the industrial and urban wastewater sector that deal with saline wastewaterThe elaboration of this book in the USC was supported by the Spanish Government (AEI) through the TREASURE project [CTQ2017-83225-C2-1-R] co-funded by FEDER (UE) and, in the UAI, by the Chilean Government through the Projects FONDECYT 1200850 and CRHIAM Centre grant number ANID/FONDAP/ 15130015. Anuska Mosquera Corral and Ángeles Val del Río belong to the Interdisciplinary Research Center in Environmental Technologies (CRETUS) and to a Galician Competitive Research Group (GRC), the latter programme cofunded by FEDER (UE) as wel

Potential of endogenous PHA as electron donor for denitrification

The use of wastewater streams to obtain polyhydroxyalkanoates (PHA) as high added-value products is widely studied. However, nitrogen removal is not well integrated into this process. In this study, the optimal conditions to track the specific endogenous denitrifying activity (SEDA) driven by PHA as carbon source were selected as: sludge concentration of 0.5–2 g VSS/L, CODPHA/N ratio higher than 5.4 g/g and between 40 and 60 mg NO3−-N/L. The seeding biomass used to perform the activity tests was collected from two sequencing batch reactors and was able to store up to 69% wt/wt of PHA. SEDA values of 0.26–0.39 g N2-N/(g VSSact d) were achieved, which proved the potential of PHA-accumulating mixed microbial cultures to be used in nitrogen removal processes. The results indicated that there is not a preference in the consumption of hydroxybutyrate over hydroxyvalerate and that PHA concentrations lower than 5% wt/wt do not allow the obtainment of the maximum SEDA value. Finally, N2O gas production was not detected in the SEDA experimentsThe authors would like to thank the Spanish Government (AEI) for funding in the frame of the projects TREASURE (CTQ2017-83225-C2-1-R) and AQUAVAL (PCIN-2017-047), this last also funded by EU in the frame of the collaborative international Consortium AQUAVAL financed under the ERA-NET WaterWorks2015 Cofunded Call. This ERA-NET is an integral part of the 2016 Joint Activities developed by the Water Challenges for a Changing World Joint Programme Initiative (Water JPI). The authors belong to the Galician Competitive Research Group (GRC-ED431C 2017-29) and to the CRETUS Strategic Partnership (ED431E 2018/01), co-funded by FEDER (UE). Angeles Val del Rio is a Xunta de Galicia fellow (ED418B 2017/075)S

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 (21.8 ± 2.8 g NaCl/L) and characterized by low pH (4.6 ± 0.6) was evaluated. This wastewater was fed to a 5-L completely stirred tank reactor operated in continuous mode. The conversion efficiency of its COD content into volatile fatty acids (VFA) was evaluated. The maximum acidification of 43% (total VFA on soluble COD basis) was obtained when an organic loading rate of 2.5 ± 0.4 g COD/(L·d) was applied to the reactor and corresponded to a VFA volumetric productivity of 0.72 ± 0.07 g CODVFA/(L·d). Under steady-state conditions, the obtained mixture of VFA was composed by 80:18:2 as acetic:propionic:butyric acids (percentage of VFA on soluble COD basis). Carbohydrates were degraded up to 96% while protein fermentation did not take place, probably due to the low pH value, limiting the maximum acidification of the wastewater. Batch experiments showed that the increase of the pH from 4.2 to 4.9 by the addition of NaHCO3 resulted in the improvement of the acidification and changed the VFA mixture composition. Thus, this study demonstrates the opportunity of using complex substrates, as cooked mussel processing wastewater, to produce rich-VFA streams under unfavourable operational conditions, such as high salinity and low pHThis research was supported 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). Special thanks to Dr. Thelmo A. Lú-Chau for his contribution to the statistical analysis of data.S

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. This microbial selection is performed in sequencing batch reactors (SBR) operated under an aerobic feast/famine (F/F) regime. In the present study, a settling stage was added at the end of the feast phase of the enrichment cycle of a SBR fed with pre-acidified cooked mussel processing wastewater (containing up to 12 g NaCl/L). Settling and subsequent supernatant discharge favoured the wash-out of non-accumulating microorganisms as well as the removal of substances that enhanced their undesired development (proteins and carbohydrates). Microbial analysis performed by fluorescence in situ hybridization (FISH) technique showed shifts in the microbial community; the presence of genus Paracoccus increased whereas genera Comamonas decreased. Moreover, the process efficiency was improved with the increase of the PHA production yield (YPHA) and the maximum PHA storage capacity (max. PHA) from 0.48 to 0.72 CmmolPHA/CmmolVFA and from 40 to 60 wt%, respectively. The polymer composition also changed, its HB:HV ratio varied from 83:17 to 70:30. Results obtained in the present study showed that settling after the feast phase promoted the removal of carbon sources that did not contribute to PHA production and the washout of non-storing bacteria, which favoured the culture enrichmentThis research was supported by the Spanish Government (AEI) through the TREASURE project [CTQ2017-83225-C2-1-R]. Lucía Argiz is a Xunta de Galicia fellow (2019), Axudas de Apoio á Etapa Predoutoral (ED481A-2019/083), grant cofunded by the operative program FSE Galicia 2014–2020. Moreover, authors would like to thank the EU and the AEI for funding, in the frame of the collaborative international Consortium AquaVal project, [PCIN-2017-047], financed under the ERA-NET WaterWorks2015 Cofunded Call. This ERA-NET is an integral part of the 2016 Joint Activities developed by the Water Challenges for a Changing World Joint Programme Initiative (Water JPI). The authors belong to CRETUS Strategic Partnership (ED4331e 2018/01) and the Galician Competitive Research Group (GRC ED431C 2017/29). All these programs are co-funded by the FEDER: Fondo Europeo de Desarrollo Regional - EU (European Union)S

Enhanced ammonia removal at room temperature by pH controlled partial nitrification and subsequent anaerobic ammonium oxidation

This is the post-print reviewed version of the following article: U. Durán, A. Val del Río, J.L. Campos, A. Mosquera-Corral & R. Méndez (2014) Enhanced ammonia removal at room temperature by pH controlled partial nitrification and subsequent anaerobic ammonium oxidation, Environmental Technology, 35:4, 383-390, DOI: 10.1080/09593330.2013.829110, which has been published in final form at http://dx.doi.org/10.1080/09593330.2013.829110. This article may be used for non-commercial purposesThe Anammox based processes are suitable for the treatment of wastewaters characterized by a low carbon to nitrogen (C/N) ratio. The application of the Anammox process requires the availability of an effluent with a NO2--N/NH4+-N ratio composition around 1 g·g-1, which involves the necessity of a previous step where the partial nitrification is performed. In this step the inhibition of the nitrite oxidizing bacteria (NOB) is crucial. In the present work a combined partial nitrification-Anammox two units system operated at room temperature (20 ºC) has been tested for the nitrogen removal of pre-treated pig slurry. To achieve the successful partial nitrification and inhibit the NOB activity different ammonium/inorganic carbon (NH4+/IC) ratios were assayed from 1.19 to 0.82 g NH4+-N·g-1 HCO3-C. This procedure provoked a decrease of the pH value to 6.0 to regulate the inhibitory effect over ammonia oxidizing bacteria (AOB) caused by free ammonia (FA). Simultaneously the NOB experienced the inhibitory effect of free nitrous acid (FNA) which avoided the presence of nitrate in the effluent. The NH4+/IC ratio which allowed the obtaining of the desired effluent composition (50% of both ammonium and nitrite) was of 0.82±0.02 g NH4+-N g-1 HCO3--C. The Anammox reactor was fed with the effluent of the partial nitrification unit containing a NO2--N/ NH4+-N ratio of 1 g·g-1 where a nitrogen loading rate (NLR) of 0.1 g N·L-1·d-1 was efficiently removedThis work was supported by CONACyT-México economic support [grant number 147817]; Xunta de Galicia [grant number10MDS265003PR]S

Pilot-scale continuous flow granular reactor for the treatment of extremely low-strength recirculating aquaculture system wastewater

The authors would like to thank the EU and the Spanish Government (AEI) (PCIN-2017-047) and Fundação para a Ciência e Tecnologia (FCT) (Water JPI/0003/2016) for funding, in the frame of the collaborative international Consortium AQUAVAL financed under the ERA-NET WaterWorks2015 Cofunded Call. This ERA-NET is an integral part of the 2016 Joint Activities developed by the Water Challenges for a Changing World Joint Programme Initiative (Water JPI) and the CDTI (Centro para Desarrollo Tecnológico Industrial, E.P.E., Spain). Authors also thank the Spanish Government (AEI) for funding, in the frame of the project TREASURE (CTQ2017-83225-C2-1-R) and the FCT for funding in the frame of the project UIDB/50016/2020. S. Santorio, A. Val del Rio and A. Mosquera-Corral belong to the Galician Competitive Research Groups (GRC)_ED431C-2021/37 co-funded by FEDER (UE)To avoid toxic ammonium and nitrite concentrations in aquaculture systems is crucial to maintain the fish production. When recirculating aquaculture systems (RAS) operate in freshwater farms during the dry seasons, the concentrations of these pollutants increase. The objective of the present study is the evaluation of a Continuous Flow Granular Reactor (CFGR) for the treatment of freshwater RAS stream at pilot-scale during two consecutive dry seasons. The CFGR was fed with a extremely low-strength recirculation stream of a trout farm (0.12–1.84 mg NH4+-N/L and 2.2–8.14 mg C/L). Two different configurations were evaluated. The first configuration consisted on a CFGR fed from the bottom, being the up-flow velocity the only shear force to mix the biomass. The second configuration incorporated a mechanical stirrer and a sieve to improve the biomass mixing and retention. The CFGR was operated at short hydraulic retention times (HRT) which ranged from 11 to 68 min. The configuration with a mechanical stirrer and sieve was optimal in terms of biomass retention and nitrogen removal performance. Despite the low nitrogen and organic matter concentrations, granulation was achieved in 55 days, with an average granule diameter up to 0.47 mm. Ammonium and nitrite removal percentages up to 81% and 100% were achieved, respectively. The ammonium and nitrite production rate in the trout farm were lower than the removal achieved by the CFGR, which makes the implementation of this system appropriated to maintain the concentration of these compounds below toxic levels for rainbow troutS

Biomass aggregation influences NaN3 short-term effects on anammox bacteria activity

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 inhibitionThe 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 samplesS

Stability of aerobic granular biomass treating the effluent from a seafood industry

This is the pre-print previous reviewed version of the following article: Val del Rio, A., Figueroa, M., Mosquera-Corral, A., Campos, J. L., & Mendez, R. (2013). Stability of Aerobic Granular Biomass Treating the Effluent from A Seafood Industry. International Journal of Environmental Research, 7(2), 265-276, which has been published in final form at https://ijer.ut.ac.ir/article_606_0.html. This article may be used for non-commercial purposesThe aerobic granular systems represent a good alternative to substitute the conventional activated sludge process in the treatment of industrial effluents due to the lower surface requirements. In this work the effluent from a seafood industry, characterized by a high variability and the presence of residual amounts of coagulant and flocculant reagents, was used to study the development of aerobic granular biomass and its stability. In a first stage with OLRs between 2 and 5 kg CODS/m3∙d the development of aerobic granular biomass was promoted with good physical properties: SVI of 35 mL/g TSS, density of 60 g VSS/Lgranule and average diameter of 2.8 mm. In a second stage the continuous change in the OLR applied from 3 to 13 kg CODS/m3∙d, to simulate the real conditions of the industry, showed that the removal of organic matter was not affected (90%) but the aerobic granules disintegrated. The maximum OLR treated in the system without granules disintegration was around 4.4 kg CODS/m3∙d. The nitrogen removal was 30% (for biomass assimilation) and the maximum ammonia removal was around 65% and depending on the solids retention time, the free ammonia concentration and the average granule diameterThis work was funded by the Spanish Government (TOGRANSYS CTQ2008-06792-C02-01, NOVEDAR_Consolider CSD2007-00055), Xunta de Galicia (project coordinated by Espina y Delfin S.L. PGIDIT06TAM004) and Ministry of Education of Spain (FPU AP2006-01478). Authors want to thank Mar Orge, Mónica Dosil and Miriam Vieites for their support in the analytical techniquesS