scholarly journals Treatment of Liquid Phase of Digestate from Agricultural Biogas Plant in a System with Aerobic Granules and Ultrafiltration

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 104 ◽  
Author(s):  
Piotr Świątczak ◽  
Agnieszka Cydzik-Kwiatkowska ◽  
Magdalena Zielińska
Keyword(s):  
Liquid Phase ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Substantial Reduction ◽  
Oxygen Demand ◽  
Aerobic Granular Sludge ◽  
Permeate Flux ◽  
Granule Formation ◽  
Nitrogen Loads ◽  
Cycle Lengths

Management of digestate from manure co-digestion with a very high chemical oxygen demand (COD) to nitrogen ratio and high nitrogen loads are a major bottleneck in the development of agricultural biogas plants. The liquid phase of digestate mixed with municipal wastewater was treated in aerobic granular sludge batch reactors at cycle lengths (t) of 6 h (GSBR6h), 8 h (GSBR8h), and 12 h (GSBR12h), corresponding to nitrogen loads of 1.6, 1.2, and 0.8 g/(L·d). Thauera sp., Lacibacter sp., Thermanaerothrix sp., and Planctomyces sp. predominated in granules favoring effective granule formation and nitrogen removal. Increasing cycle lengths (t) significantly decreased proteins in soluble fraction of extracellular polymeric substances (EPS) in granules and increased polysaccharides in tightly bound EPS that resulted in higher granule diameters and higher COD removal. In GSBR6h, heterotrophic nitrification/denitrification was very efficient, but ammonium was fully oxidized in the last hour of the cycle. So in further studies, the effluent from GSBR8h was subjected to ultrafiltration (UF) at transmembrane pressures (TMPs) of 0.3, 0.4, and 0.5 MPa. A GSBR8h-UF system (TMP of 0.4 MPa) ensured full removal of total Kjeldahl nitrogen (TKN), suspended solids, and substantial reduction of COD and color with good permeate flux. The NOx-rich (about 250 mg/L), clear permeate can be reused in line with assumptions of modern circular economy.

scholarly journals Anaerobic hydrolysis of complex substrates in full-scale aerobic granular sludge: enzymatic activity determined in different sludge fractions

2021 ◽  
Author(s):  
Sara Toja Ortega ◽  
Mario Pronk ◽  
Merle K. de Kreuk
Keyword(s):  
Hydrolytic Enzymes ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Granular Sludge ◽  
Hydrolytic Activity ◽  
Full Scale ◽  
Aerobic Granular Sludge ◽  
Bulk Liquid ◽  
Granule Formation ◽  
Hydrolysis Of

Abstract Complex substrates, like proteins, carbohydrates, and lipids, are major components of domestic wastewater, and yet their degradation in biofilm-based wastewater treatment technologies, such as aerobic granular sludge (AGS), is not well understood. Hydrolysis is considered the rate-limiting step in the bioconversion of complex substrates, and as such, it will impact the utilization of a large wastewater COD (chemical oxygen demand) fraction by the biofilms or granules. To study the hydrolysis of complex substrates within these types of biomass, this paper investigates the anaerobic activity of major hydrolytic enzymes in the different sludge fractions of a full-scale AGS reactor. Chromogenic substrates were used under fully mixed anaerobic conditions to determine lipase, protease, α-glucosidase, and β-glucosidase activities in large granules (>1 mm in diameter), small granules (0.2–1 mm), flocculent sludge (0.045–0.2 mm), and bulk liquid. Furthermore, composition and hydrolytic activity of influent wastewater samples were determined. Our results showed an overcapacity of the sludge to hydrolyze wastewater soluble and colloidal polymeric substrates. The highest specific hydrolytic activity was associated with the flocculent sludge fraction (1.5–7.5 times that of large and smaller granules), in agreement with its large available surface area. However, the biomass in the full-scale reactor consisted of 84% large granules, making the large granules account for 55–68% of the total hydrolytic activity potential in the reactor. These observations shine a new light on the contribution of large granules to the conversion of polymeric COD and suggest that large granules can hydrolyze a significant amount of this influent fraction. The anaerobic removal of polymeric soluble and colloidal substrates could clarify the stable granule formation that is observed in full-scale installations, even when those are fed with complex wastewaters. Key points • Large and small granules contain >70% of the hydrolysis potential in an AGS reactor. • Flocculent sludge has high hydrolytic activity but constitutes <10% VS in AGS. • AGS has an overcapacity to hydrolyze complex substrates in domestic wastewater. Graphical abstract

Biological treatment of wastewater from fruit juice production using a membrane bioreactor: parameters limiting membrane performance

2003 ◽  
Vol 3 (5-6) ◽  
pp. 253-259
Author(s):  
C. Blöcher ◽  
T. Britz ◽  
H.D. Janke ◽  
H. Chmiel
Keyword(s):  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Fruit Juice ◽  
Operating Conditions ◽  
Production Plant ◽  
Permeate Flux ◽  
Produce Water ◽  
Membrane Performance ◽  
Test Operation

The application of a membrane bioreactor (MBR) was investigated to treat polluted process water from fruit juice processing. The aim was either direct discharge or further treatment by nanofiltration/low pressure reverse osmosis to produce water of drinking quality. The results of a one-year test operation of the process in industrial scale at a fruit juice production plant are presented. Focus was centred on the influence of activated sludge characteristics on membrane performance. Under the operating conditions in place, neither solids content, particle size distribution nor addition of nutrient significantly affected the permeate flux which was considerably lower than expected (based on municipal wastewater treatment with MBRs). Instead, evidence was obtained that the insufficient permeate flux was most likely due to the high content of extracellular polymeric substances. However, it was impossible to relate in detail the substantial flux variations during the test run to AS characteristics or changes in microbial population.

Combination of microalgae cultivation with membrane processes for the treatment of municipal wastewater

2013 ◽  
Vol 68 (11) ◽  
pp. 2374-2381 ◽  
Author(s):  
Lu Chen ◽  
Jiang Wei ◽  
Weiguo Wang ◽  
Cunwen Wang
Keyword(s):  
Chemical Oxygen Demand ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Permeate Flux ◽  
Microalgae Cultivation ◽  
New Approach ◽  
Critical Issues ◽  
Uf Membranes ◽  
Residual Solution

The treatment of wastewater by microalgae cultivation has attracted more and more attention. However, the way to harvest microalgae cells from the wastewater and the treatment of the large quantity of residual solution have become critical issues. In this work, a new approach for the treatment of municipal wastewater is presented. The combination of flocculation for removing mainly microalgae and thereafter membrane filtration for chemical oxygen demand (COD) and conductivity reduction of the residual solution after flocculation is discussed. The COD concentration of the wastewater decreased from 260 to 84 mg/L after flocculation by chitosan. Five ultrafiltration (UF) membranes and two nanofiltration (NF) membranes were used for filtration to find a suitable membrane for COD and conductivity reduction. Among the five UF membranes, GR82PE showed the best performance, whose permeate flux and COD retention at 4 bar were 189.66 L/(m2·h) and 43.03%, respectively. NF membranes showed higher COD and conductivity retentions than UF membranes. The COD retention of Desal5-DK reached 98.3% at 20 bar. Lastly, the flux recovery after the filtration test of each membrane is also discussed.

scholarly journals Effect of Increased Influent COD on Relieving the Toxicity of CeO2 NPs on Aerobic Granular Sludge

2019 ◽  
Vol 16 (19) ◽  
pp. 3609 ◽  
Author(s):  
Xiaoying Zheng ◽  
Yuan Zhang ◽  
Wei Chen ◽  
Weihong Wang ◽  
Hang Xu ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Inhibitory Effect ◽  
Environmental Risks ◽  
Pollutant Removal ◽  
Aerobic Granular Sludge ◽  
Long Term Effects ◽  
Negative Effects

Due to the increased use of cerium oxide nanoparticles (CeO2 NPs), their potential environmental risks have caused concern. However, their effects on the aerobic granular sludge (AGS) process and the later recovery of AGS are still unclear. In this study, we comprehensively determined the changes in pollutant removal and the levels of extracellular polymeric substances (EPS) in AGS that were exposed to CeO2 NP treatments (0 (the control, R0), 1 (R1), and 5 (R5) mg/L), following an increase in the influent chemical oxygen demand (COD). An increase in the CeO2 NP concentration enhanced their inhibitory effect on the removal of total nitrogen (TN) and total phosphorus (TP), and promoted the production of polysaccharides (PS) and proteins (PN) in loosely bound EPS (LB-EPS) or tightly bound EPS (TB-EPS), as well as the dissolved organic carbon (DOC) components in EPS, but had no long-term effects on the removal of organic matter. When the addition of CeO2 NPs was stopped and the concentration of influent COD increased, the TN and TP removal efficiencies in R1 and R5 slowly increased and recovered. In R1, they were only 4.55 ± 0.55% and 2.71 ± 0.58% lower than in R0, respectively, while the corresponding values for R5 were 5.06 ± 0.46% and 6.20 ± 0.63%. Despite the LB-EPS and TB-EPS concentrations in the R1 and R5 treatments recovering and being similar to the levels in the control when no CeO2 NPs were added, they were still slightly higher than in the R0, which indicating that the negative effects of CeO2 NPs could not be completely eliminated due to the residual CeO2 NP levels in AGS.

scholarly journals Microbiological and physicochemical evaluation of the effluent quality in a membrane bioreactor system to meet the legislative limits for wastewater reuse

2017 ◽  
Vol 76 (7) ◽  
pp. 1796-1804 ◽  
Author(s):  
Konstantinos Azis ◽  
Charalampos Vardalachakis ◽  
Spyridon Ntougias ◽  
Paraschos Melidis
Keyword(s):  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Wastewater Reuse ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Effluent Quality ◽  
Mediterranean Countries

The aim of this study was to assess the efficacy and effluent quality of a pilot-scale intermittently aerated and fed, externally submerged membrane bioreactor (MBRes) treating municipal wastewater. The effluent quality of the MBRes was evaluated regarding system ability to comply with the Greek legislative limits for restricted and unrestricted wastewater reuse. The average permeate flux was 13.9 L m−2 h−1, while the transmembrane pressure remained above the level of −110 mbar. Experimental data showed that biochemical oxygen demand, chemical oxygen demand, total nitrogen, PO43−- P and total suspended solids removal efficiencies were 97.8, 93.1, 89.6, 93.2 and 100%, respectively, whereas turbidity was reduced by 94.1%. Total coliforms and Escherichia coli were fully eliminated by ultrafiltration and disinfection methods, such as chlorination and ultraviolet radiation. In agreement with the Greek legislation (Joint Ministerial Decree 145116/11) and the guidelines recommended for the Mediterranean countries, the disinfected effluent of the MBRes system can be safely reused directly for urban purposes.

scholarly journals Membrane Bioreactor Technology: The Effect of Membrane Filtration on Biogas Potential of the Excess Sludge

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 397
Author(s):  
Magdalena Zielińska ◽  
Katarzyna Bernat ◽  
Wioleta Mikucka
Keyword(s):  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
High Efficiency ◽  
Ceramic Membrane ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Excess Sludge

Although the membrane bioreactor technology is gaining increasing interest because of high efficiency of wastewater treatment and reuse, data on the anaerobic transformations of retentate are scarce and divergent. The effects of transmembrane pressure (TMP) in microfiltration (MF) and ultrafiltration (UF) on the pollutant rejection, susceptibility of ceramic membrane to fouling, hydraulic parameters of membrane module, and biogas productivity of retentate were determined. Irrespective of the membrane cut-off and TMP (0.2–0.4 MPa), 97.4 ± 0.7% of COD (chemical oxygen demand), 89.0 ± 4.1% of total nitrogen, and 61.4 ± 0.5% of total phosphorus were removed from municipal wastewater and the permeates can be reused for irrigation. Despite smaller pore diameter, UF membrane was more hydraulically efficient. MF membrane had 1.4–4.6 times higher filtration resistances than UF membrane. In MF and UF, an increase in TMP resulted in an increase in permeate flux. Despite complete retention of suspended solids, strong shearing forces in the membrane installation changed the kinetics of biogas production from retentate in comparison to the kinetics obtained when excess sludge from a secondary clarifier was anaerobically processed. MF retentates had 1.15 to 1.28 times lower cumulative biogas production than the excess sludge. Processing of MF and UF retentates resulted in about 60% elongation of period in which 90% of the cumulative biogas production was achieved.

scholarly journals Composition and Distribution of Extracellular Polymeric Substances in Aerobic Flocs and Granular Sludge

2005 ◽  
Vol 71 (2) ◽  
pp. 1051-1057 ◽  
Author(s):  
B. S. McSwain ◽  
R. L. Irvine ◽  
M. Hausner ◽  
P. A. Wilderer
Keyword(s):  
Extracellular Polymeric Substances ◽  
Cation Exchange Resin ◽  
Chemical Characterization ◽  
Granular Sludge ◽  
Cell Lysis ◽  
Heat Extraction ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Chemical Extraction ◽  
Granule Formation

ABSTRACT Extracellular polymeric substances (EPS) were quantified in flocculent and aerobic granular sludge developed in two sequencing batch reactors with the same shear force but different settling times. Several EPS extraction methods were compared to investigate how different methods affect EPS chemical characterization, and fluorescent stains were used to visualize EPS in intact samples and 20-μm cryosections. Reactor 1 (operated with a 10-min settle) enriched predominantly flocculent sludge with a sludge volume index (SVI) of 120 ± 12 ml g−1, and reactor 2 (2-min settle time) formed compact aerobic granules with an SVI of 50 ± 2 ml g−1. EPS extraction by using a cation-exchange resin showed that proteins were more dominant than polysaccharides in all samples, and the protein content was 50% more in granular EPS than flocculent EPS. NaOH and heat extraction produced a higher protein and polysaccharide content from cell lysis. In situ EPS staining of granules showed that cells and polysaccharides were localized to the outer edge of granules, whereas the center was comprised mostly of proteins. These observations confirm the chemical extraction data and indicate that granule formation and stability are dependent on a noncellular, protein core. The comparison of EPS methods explains how significant cell lysis and contamination by dead biomass leads to different and opposing conclusions.

scholarly journals Sulfate reducing bacteria applied to domestic wastewater

2018 ◽  
Vol 13 (3) ◽  
pp. 542-554 ◽  
Author(s):  
Tessa van den Brand ◽  
Laura Snip ◽  
Luc Palmen ◽  
Paul Weij ◽  
Jan Sipma ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Sulfate Reducing Bacteria ◽  
Granule Formation ◽  
Sulfate Reducing ◽  
Domestic Wastewater Treatment ◽  
Reducing Bacteria

Abstract The application of sulfate reducing bacteria (SRB) to treat municipal wastewater is seldom considered. For instance, due to low sludge yield it can reduce the amount of excess sludge produced significantly. Several studies, mainly at laboratory-scale, revealed that SRB can proliferate in artificial wastewater systems at temperatures of 20°C and lower. So far, the application of SRB in a domestic wastewater treatment plant has been limited. Therefore, this study evaluates the proliferation of SRB at pilot-scale in a moderate climate. This study revealed that SRB were present and active in the pilot fed with domestic wastewater at 13°C, and outcompete methanogens. Stable, smooth and well-settled granule formation occurred, which is beneficial for full-scale application. In the Netherlands the sulfate concentration is usually low (&lt;500 mg/L), therefore the application of SRB seems challenging as sulfate is limiting. Additional measurements indicated the presence of other sulfur sources, therefore higher sulfur levels were available, which makes it possible to remove more than 75% of the chemical oxygen demand (excluding sulfide) based on SRB activity. The beneficial application of SRB to domestic wastewater treatment might therefore be valid for more locations than initially expected.

Performance of aerobic granular sludge at variable circulation rate in anaerobic–aerobic conditions

2014 ◽  
Vol 69 (11) ◽  
pp. 2252-2257 ◽  
Author(s):  
Hasnida Harun ◽  
Aznah Nor Anuar ◽  
Zaini Ujang ◽  
Noor Hasyimah Rosman ◽  
Inawati Othman
Keyword(s):  
Municipal Wastewater ◽  
Granular Sludge ◽  
Ammonia Removal ◽  
Soy Sauce ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Circulation Rate ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Mixed Liquor

Aerobic granular sludge (AGS) has been applied to treat a broad range of industrial and municipal wastewater. AGS can be developed in a sequencing batch reactor (SBR) with alternating anaerobic–aerobic conditions. To provide anaerobic conditions, the mixed liquor is allowed to circulate in the reactor without air supply. The circulation flow rate of mixed liquor in anaerobic condition is the most important parameter of operation in the anaerobic-AGS processes. Therefore, this study investigates the effect of circulation rate on the performance of the SBR with AGS. Two identical reactors namely R1 and R2 were operated using fermented soy sauce wastewater at circulation rate of 14.4 and 36.0 l/h, respectively. During the anaerobic conditions, the wastewater was pumped out from the upper part of the reactor and circulated back into the bottom of the reactor for 230 min. A compact and dense AGS was observed in both reactors with a similar diameter of 2.0 mm in average, although different circulation rates were adopted. The best reactor performance was achieved in R2 with chemical oxygen demand removal rate of 89%, 90% total phosphorus removal, 79% ammonia removal, 10.1 g/l of mixed liquor suspended solids and a sludge volume index of 25 ml/g.

Correlation between membrane fouling and soluble/colloidal organic substances in membrane bioreactors for municipal wastewater treatment

2005 ◽  
Vol 51 (6-7) ◽  
pp. 1-8 ◽  
Author(s):  
B. Lesjean ◽  
S. Rosenberger ◽  
C. Laabs ◽  
M. Jekel ◽  
R. Gnirss ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Membrane Bioreactors ◽  
Size Exclusion ◽  
Water Phase ◽  
Parallel Operation ◽  
Municipal Wastewater Treatment ◽  
Operational Conditions ◽  
The Difference

Two similar membrane bioreactors of 2 m3 each were operated in parallel over two years under the same operational conditions, fed with the same municipal wastewater. The only process and operational difference between both pilot plants was the position of the denitrification zone (pre-denitrification in pilot 1 and post-denitrification in pilot 2). Despite parallel operation, the two MBRs exhibited different fouling rates and decreases in permeability. These differences could not be accounted for by MLSS concentrations, loading rates, or filtration flux. In a one-year investigation, soluble and colloidal organic material in the activated sludge of both MBR was regularly analysed by spectrophotometric and Size Exclusion Chromatography (SEC) methods. The larger organic molecules present in the sludge water phase (i.e. polysaccharides, proteins and organic colloids) originating from microbial activity (extracellular polymeric substances) were found to impact on the fouling and to explain the difference in membrane performance between the two MBR units. In both pilot plants, a linear relationship could be clearly demonstrated between the fouling rate of the membrane and the concentration of polysaccharides in the sludge water phase during a 5 month operational period at an SRT of 8 days.

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