Extreme industrial effluents: Opportunities for reuse

Sanitary Engineerin

De industrie en haar watergebruik

Net als huishoudens hebben bedrijven door de eeuwen heen allerlei afvalstoffen geloosd en het water vervuild. De industrie gebruikt veel water van een heel scala aan kwaliteiten, van ultrapuur tot licht verontreinigd, brak of zelfs zout. Tegenwoordig wordt een groot gedeelte van het gebruikte water gezuiverd en hergebruikt. Maar dit is niet altijd het geval. Soms is bij de huidige stand van techniek of investeringen zuiveren geen optie en moet het gebruikte water worden geloosd. Dit industrieel afvalwater is een mix van diverse stromen, vaak met hoge concentratie aan specifieke stoffen en zouten. De invoering van de Wet Verontreiniging Oppervlaktewateren heeft voor veel innovaties op zuiveringsgebied gezorgd, om ook uit dit afvalwater nog bruikbaar water en stoffen te halen.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin

Impact of adding aluminum hydroxyl chloride on membrane flux in an anaerobic membrane bioreactor

Coagulant addition and improved mixing conditions have been used in anaerobic membrane bioreactors (AnMBR) to improve membrane performance. Before coagulant was added, a flux of 8 L/m2 h was applicable and transmembrane pressure (TMP) increased from 1 kPa to 10 kPa in 5 days. However, after the coagulant was added, a flux as high as 50 L/m2 h was achieved with no noticeable increase in TMP during six hours of operation. Furthermore, at the same high flux, a long-term experiment showed that TMP increased to approximately 3 kPa in 20 days. Apparently, the applied coagulant significantly improved membrane performance. The reduction in the number of small particles was identified as the main cause for the high flux. However, the number of submicon particles increased in the long-term experiment. In addition, a model was developed that adequately described the TMP development in the short-term and long-term experiments. According to this model, the deterioration in specific cake resistance resulted in a sharp TMP increase in the long-term experiment. In addition, experiments showed that the effect of coagulant on sludge activity was minimal. This study demonstrated that the applied coagulant and reactor operation conditions (mixing properties) have potentials of interest for improving the membrane flux in AnMBR.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin

Removal of total ammoniacal nitrogen from reject water through selective electrodialysis reversal and bipolar electrodialysis

The removal of ammonium and ammonia, represented as total ammoniacal nitrogen (TAN), from reject water through electro-dialysis (ED) and bipolar membrane electrodialysis (BPMED) encounters challenges such as organic fouling, NH3 back-diffusion, and high energy consumption. The efficacy of electrodialysis reversal (EDR) combined with bipolar membrane electrodialysis using cation-exchange membranes (BPC) was assessed as a more practical configuration (EDR + BPC). Additionally, a novel configuration involving monovalent selective cation-exchange membranes (MSCEMs) in an EDR + BPC setup (SEDR + BPC) was investigated. Comparisons were made among BPMED, EDR + BPC, and SEDR + BPC under three load ratios (LN) of 0.8, 1, and 1.3 during continuous operation. The innovative SEDR + BPC configuration, with an LN of 0.8, exhibited the lowest energy consumption for transported TAN (ETAN) at 4.4 MJ·kgN−1 removal and achieved the highest TAN removal efficiency of 78 % with an LN of 1.3. In contrast to conventional BPMED, SEDR + BPC allowed for the recovery of potentially back-diffused NH3 into the acid chamber, minimizing transport losses. Furthermore, scaling in the base chamber was reduced due to the contribution of MSCEMs when applying an LN of 0.8. The MSCEMs increased the molar ratio of TAN over (Mg2+ + Ca2+) in the concentrate and decreased it in the diluate. EDR + BPC and SEDR + BPC configurations exhibited stable and lower cell resistance throughout the operation compared to BPMED, attributed to their ability to generate higher concentration gradients. The results clearly demonstrated the feasibility of low-energy TAN removal from real reject water from sludge anaerobic digestion using the SEDR + BPC setup.Sanitary Engineerin

Fungal treatment of humic-rich industrial wastewater: application of white rot fungi in remediation of food-processing wastewater

This paper presents the results of fungal treatment of a real industrial wastewater (WW), providing insight into the main mechanisms involved and clarifying some ambiguities and uncertainties in the previous reports. In this regard, the mycoremediation potentials of four strains of white rot fungi (WRF): Phanerochaete chrysosporium, Trametes versicolor, Pleurotus ostreatus and Pleurotus pulmonarius were tested to remove humic acids (HA) from a real humic-rich industrial treated WW of a food-processing plant. The HA removal was assessed by color measurement and size-exclusion chromatography (SEC) analysis. T. versicolor showed the best decolorization efficiency of 90% and yielded more than 45% degradation of HA, which was the highest among the tested fungal strains. The nitrogen limitation was studied and results showed that it affected the fungal extracellular laccase and manganese peroxidase (MnP) activities. The results of the SEC analysis revealed that the mechanism of HA removal by WRF involves degradation of large HA molecules to smaller molecules, conversion of HA to fulvic acid-like molecules and also biosorption of HA by fungal mycelia. The effect of HS on the growth of WRF was investigated and results showed that the inhibition or stimulation of growth differs among the fungal strains.Sanitary Engineerin

Optimising the Flux Enhancer Dosing Strategy in a Pilot-Scale Anaerobic Membrane Bioreactor by Mathematical Modelling

Flux enhancers (FEs) have been successfully applied for fouling mitigation in membrane bioreactors. However, more research is needed to compare and optimise different dosing strategies to improve the filtration performance, while minimising the use of FEs and preventing overdosing. Therefore, the goal of this research is to develop an optimised control strategy for FE dosing into an AnMBR by developing a comprehensive integrated mathematical model. The integrated model includes filtration, flocculation, and biochemical processes to predict the effect of FE dosing on sludge filterability and membrane fouling rate in an AnMBR. The biochemical model was based on an ADM1, modified to include FEs and colloidal material. We developed an empirical model for the FE‐induced flocculation of colloidal material. Various alternate filtration models from the literature and our own empirical models were implemented, calibrated, and validated; the best alternatives were selected based on model accuracy and capacity of the model to predict the effect of varying sludge characteristics on the corresponding output, that is fouling rate or sludge filterability. The results showed that fouling rate and sludge filterability were satisfactorily predicted by the selected filtration models. The best integrated model was successfully applied in the simulation environment to compare three feedback and two feedforward control tools to manipulate FE dosing to an AnMBR. The modelling results revealed that the most appropriate control tool was a feedback sludge filterability controller that dosed FEs continuously, referred to as ∆R 20_10. Compared to the other control tools, application of the ∆R 20_10 controller resulted in a more stable sludge filterability and steady fouling rate, when the AnMBR was subject to specific disturbances. The simulation environment developed in this research was shown to be a useful tool to test strategies for dosing flux enhancer into AnMBRs. Sanitary Engineerin

A novel approach for application of white rot fungi in wastewater treatment under non-sterile conditions: immobilization of fungi on sorghum

In this study, we tested a new approach to facilitate the application of white rot fungi (WRF) under non-sterile conditions, by introducing grain sorghum as carrier and sole carbon and nutrient source for WRF. To this end, Trametes versicolor was immobilized on sorghum, and its ability to remove humic acid (HA) from synthetic and real industrial wastewater was studied. HA removal was measured as colour reduction and also analysed via size exclusion chromatography (SEC). Under sterile conditions, 80% colour removal was achieved for both synthetic and real wastewater using immobilized WRF on sorghum, without adding any additional carbon or nutrient sources. Under non-sterile conditions, immobilized fungi could again remove 80% of the colour and reached a maximum of 40 U/L laccase activity. In contrast, non-immobilized fungi cultivated in non-sterile wastewater supplemented with additional nutrients, reached only 10% decolourization and maximum 5 U/L laccase activity. SEC analysis showed that bioremoval of HA by WRF was associated with degradation of HA. Finally, immobilized fungi were used to treat real wastewater, under non-sterile conditions, in a sequential batch order without renewing the immobilized fungi. Four batch feedings were conducted and 80%, 70%, 50% and 40% colour removal was achieved for each batch, respectively, over a total incubation period of 19 days.Sanitary Engineerin

Enhancing Volatile Fatty Acid Production during Anaerobic Fermentation of Waste Activated Sludge with Persulfates: Peroxymonosulfate versus Peroxydisulfate

Persulfates ((peroxymonosulfate (PMS) and peroxydisulfate (PDS)) can disintegrate waste activated sludge (WAS), but their influence on volatile fatty acid (VFA) production during anaerobic fermentation is largely unclear. Particularly, it is unknown whether persulfates can improve fermentation without any preactivation. This study investigated how the direct addition of PMS and PDS into the fermenter influences VFA production from WAS, and uncovered possible mechanisms of improved VFA production. At the PMS dosage of 1.0 mM/gVS, maximum VFA yield (1025 ± 55 mg COD/L) was observed in 5 days of fermentation, which was 24% higher than that with an equimolar addition of PDS and 132% higher than that without persulfate addition. However, the cost-effectiveness of PMS in enhancing VFA production is lower than that of PDS. The in situ generated hydroxyl and sulfate radicals from persulfates in the fermenter enhanced not only WAS disintegration and solubilization but also the formation of biodegradable substances for acidification. Moreover, the direct addition of persulfates into the fermenter shifted the microbial community toward hydrolysis-acidification such as Clostridium_sensu_stricto_10 and Fonticella. Results of this study also suggest that preactivation is not necessary when persulfates are applied to improve WAS fermentation.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin

Fuelling a solid oxide fuel cell with ammonia recovered from water by vacuum membrane stripping

Gaseous ammonia (NH3) recovered from residual waters may be used as a fuel in solid oxide fuel cells (SOFCs) to generate electricity without emission of undesirable oxidised nitrogen species. NH3 can be directly recovered from water as a gas by vacuum membrane stripping (VMS), which also results in the evaporation of water (H2O), leading to the recovery of NH3-H2O mixtures. However, in currently available literature, information is lacking on the NH3 concentrations in NH3-H2O mixtures that may be used as a fuel for an oxygen-conducting SOFC (SOFC-O). In this study, we assessed the effect of feed water temperature and the NH3 feed water concentration on the NH3 concentrations in gaseous VMS permeate. Besides, we assessed the feasibility to use NH3-H2O mixtures in the concentration range between 5 and 25 wt% for the generation of electricity in an SOFC-O. The results show that increasing the NH3 feed water concentration from 1 to 10 g∙L−1 increased the NH3 concentration in the gaseous VMS permeate from 1 wt% to up to 11 wt%. Increasing the feed water temperature from 25 to 35 °C also results in an increase in the NH3 concentration in the gaseous permeate, whereas increasing the feed water temperature from 35 °C to 55 °C leads to dilution of the VMS permeate. Furthermore, electricity was generated at an electrical efficiency of 43% in an SOFC-O when the NH3 concentration in the NH3-H2O fuel was only 5 wt%. Hence, according results on the obtained NH3 concentrations in the gaseous VMS permeate and the generation of electricity using dilute NH3-H2O mixtures as a fuel, VMS and SOFC-O can be combined for the generation of electricity from NH3 recovered from water. Moreover, the electrical energy generation of the SOFC-O, which reached values of 9 MJ∙kg-N−1, was higher than the electrical energy consumption for VMS, for which values of 7 MJ∙kg-N−1 were calculated.Sanitary Engineerin

Application of dynamic current density for increased concentration factors and reduced energy consumption for concentrating ammonium by electrodialysis

Ammonium (NH4+) can be recovered from water for fertiliser production or even energy production purposes. Because NH4+ recovery is more effective at increased concentrations, electrodialysis (ED) can be used to concentrate NH4+ from side streams, such as sludge reject water, and simultaneously achieve high NH4+ removal efficiencies. However, the effect of osmosis and back-diffusion increases when the NH4+ concentration gradient between the diluate and the concentrate stream increases, resulting in a limitation of the concentration factor and an increase in energy consumption for NH4+ removal. In this study, we showed that operation at dynamic current density (DCD) reduced the effect of osmosis and back-diffusion, due to a 75% decrease of the operational run time, compared to operation at a fixed current density (FCD). The concentration factor increased from 4.5 for an FCD to 6.7 for DCD, while the energy consumption of 90% NH4+ removal from synthetic sludge reject water at DCD remained stable at 5.4 MJ·kg-N−1.Sanitary Engineerin