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

Aerobic granular sludge technology and nitrogen removal for domestic wastewater treatment

2015 ◽  
Vol 71 (7) ◽  
pp. 1040-1046 ◽  
Author(s):  
J. Wagner ◽  
L. B. Guimarães ◽  
T. R. V. Akaboci ◽  
R. H. R. Costa
Keyword(s):  
Nitrogen Removal ◽  
Domestic Wastewater ◽  
Granular Sludge ◽  
Ammonium Assimilation ◽  
Aerobic Granular Sludge ◽  
Granule Formation ◽  
Granulation Process ◽  
Start Up ◽  
Domestic Wastewater Treatment ◽  
Average Size

This study evaluated aerobic granulation and nitrogen removal via assimilation, nitrification, and denitrification of a system fed with real domestic wastewater. The granulation process was complete after 160 days of operation. The mature granules had an almost spherical structure, an average size of 473.0 μm, and a good settling ability (SVI30 of 75.6 mL g−1). Ammonium assimilation for cell growth varied between 3.5 and 64.6% during reactor start-up. After granule formation, assimilation accounted for less than 5% and nitrogen was mainly removed by partial nitrification up to nitrite, followed by denitrification via nitrite. Average efficiencies of 86.6% for nitrification, 59.5% for denitrification, and 60.5% for total nitrogen were obtained in this period. The assimilation ability of the mature granules grown on domestic wastewater was lower than the commonly reported results obtained for synthetic granules.

scholarly journals DEVELOPMENT OF AEROBIC GRANULES IN SEQUENCING BATCH REACTOR SYSTEM FOR TREATING HIGH TEMPERATURE DOMESTIC WASTEWATER

2019 ◽  
Vol 81 (3) ◽  
Author(s):  
Mohd Hakim Ab Halim ◽  
Aznah Nor Anuar ◽  
Shreeshivadasan Chelliapan ◽  
Norhaliza Abdul Wahab ◽  
Hazlami Fikri Basri ◽  
...  
Keyword(s):  
High Temperature ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Biomass Concentration ◽  
Domestic Wastewater ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Hot Climate

The application of aerobic granular sludge (AGS) in treating real domestic wastewater at high temperature is still lacking. In this study, the microstructure and morphology of the granules, as well as bioreactor performance, were investigated during the treatment of real domestic wastewater at high temperature (50 °C). The experiment was executed in a sequencing batch reactor (SBR) with a complete cycle time of 3 hours for the treatment of low-strength domestic wastewater at an organic loading rate (OLR) of 0.6 kg COD m−3 d−1. Stable mature granules with average diameters between 2.0 and 5.0 mm, and good biomass concentration of 5.8 g L−1 were observed in the bioreactor. AGS achieved promising results in the treatment of domestic wastewater with good removal rates of 84.4 %, 99.6 % and 81.7 % for chemical oxygen demand (COD), ammoniacal nitrogen (NH3−N), and total phosphorus (TP), respectively. The study demonstrated the formation capabilities of AGS in a single, high and slender column type-bioreactor at high temperature which is suitable to be applied in hot climate condition areas especially countries with tropical and desert-like climates.

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 Efficient carbon, nitrogen and phosphorus removal from low C/N real domestic wastewater with aerobic granular sludge

2020 ◽  
Vol 305 ◽  
pp. 122961 ◽  
Author(s):  
Riccardo Campo ◽  
Sara Sguanci ◽  
Simone Caffaz ◽  
Lorenzo Mazzoli ◽  
Matteo Ramazzotti ◽  
...  
Keyword(s):  
Phosphorus Removal ◽  
Domestic Wastewater ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal

Material selection for a constructed wetroof receiving pre-treated high strength domestic wastewater

2013 ◽  
Vol 68 (10) ◽  
pp. 2264-2270 ◽  
Author(s):  
M. Zapater-Pereyra ◽  
F. van Dien ◽  
J. J. A. van Bruggen ◽  
P. N. L. Lens
Keyword(s):  
Wastewater Treatment ◽  
Material Selection ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
High Strength ◽  
Full Scale ◽  
Water Dynamics ◽  
Long Term Stability ◽  
Wastewater Pollutants ◽  
Clay Aggregates

A constructed wetroof (CWR) is defined in this study as the combination of a green roof and a constructed wetland: a shallow wastewater treatment system placed on the roof of a building. The foremost challenge of such CWRs, and the main aim of this investigation, is the selection of an appropriate matrix capable of assuring the required hydraulic retention time, the long-term stability and the roof load-bearing capacity. Six substrata were subjected to water dynamics and destructive tests in two testing-tables. Among all the materials tested, the substratum configuration composed of sand, light expanded clay aggregates, biodegradable polylactic acid beads together with stabilization plates and a turf mat is capable of retaining the water for approximately 3.8 days and of providing stability (stabilization plates) and an immediate protection (turf mat) to the system. Based on those results, a full-scale CWR was built, which did not show any physical deterioration after 1 year of operation. Preliminary wastewater treatment results on the full-scale CWR suggest that it can highly remove main wastewater pollutants (e.g. chemical oxygen demand, PO43−-P and NH4+-N). The results of these tests and practical design considerations of the CWR are discussed in this paper.

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