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

Treatment and Valorisation of Saline Wastewater

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 wastewater

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

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

A novel control strategy for enhancing biological N-removal in a granular sequencing batch reactor : a model-based study

Biological nitrogen removal in aerobic granular sequencing batch reactors is sensitively affected by process conditions (e.g. dissolved oxygen (DO) concentration, nitrogen loading rate (NLR), influent C/N ratio, among others). The variation of one of these process conditions affects the others, because often they are tightly linked. These interrelationships are a drawback for the experimental assessment of the target domain of process conditions required to enhance N-removal. Here, we have developed a model to determine the guidelines to design an automatic control strategy with the final aim of enhancing biological N-removal in a granular sequencing batch reactor. The model was first calibrated with experimental data from a granular sequencing batch reactor treating swine wastewater. Specific simulations were designed to elucidate the effect of DO concentration (0.5-8 mg O₂ L⁻¹), granule size (0.5-3.5 mm), influent C/N ratio (4-10 g O₂g⁻¹ N) and NLR (0.41-0.82 g N L⁻¹ d⁻¹) on the nitrification- enitrification efficiency. Simulation results showed that, in general, high N-removal efficiencies (from 70% to 85%) could be obtained only setting the appropriate DO concentration. That appropriate DO concentration could be easily found based on effluent ammonium concentration. Those results were used to propose a control strategy to enhance N-removal efficiencies. The control strategy was based on a closed DO loop with variable DO set-point. The DO set-point was established at a constant value for the whole cycle (i.e. once per cycle), based on the on-line measurement of ammonium concentration at the end of the previous cycle

Feasible microbial accumulation of triacylglycerides from crude glycerol

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 VersionsBACKGROUND: 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 processThis 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 Partnership (AGRUP2015/02). All of these programmes are co-funded by the FEDER (EU)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

Effects of short- and long-term exposures of humic acid on the Anammox activity and microbial community

Humic acid has a controversial effect on the biological treatment processes. Here, we have investigated humic acid effects on the Anammox activity by studying the nitrogen removal efficiencies in batch and continuous conditions and analyzing the microbial community using Fluorescence in situ hybridization (FISH) technique. The results showed that the Anammox activity was affected by the presence of humic acid at a concentration higher than 70 mg/L. In fact, in the presence of humic acid concentration of 200 mg/L, the Anammox activity decreased to 57% in batch and under continuous condition, the ammonium removal efficiencies of the reactor decreased from 78 to 41%. This reduction of Anammox activity after humic acid addition was highlighted by FISH analysis which revealed a considerable reduction of the abundance of Anammox bacteria and the bacteria living in symbiosis with them. Furthermore, a total inhibition of Candidatus Brocadia fulgida was observed. However, humic acid has promoted heterotrophic denitrifying bacteria which became dominant in the reactor. In fact, the evolution of the organic matter in the reactor showed that the added humic acid was used as carbon source by heterotrophic bacteria which explained the shift of metabolism to the favor of heterotrophic denitrifying bacteria. Accordingly, humic acid should be controlled in the influent to avoid Anammox activity inhibition.This research work is financially supported by the Tunisian Ministry of Higher Education, Scientific Research and TechnologyS

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