Upflow Anaerobic Sludge Blanket Treatment Research Articles

Using amino acid waste liquid as functional supplement to change microbial community in up-flow anaerobic sludge blanket treatment of methanolic wastewater.

In this study, amino acid waste liquid was employed as a functional supplement (designated as amino acid-rich FS) in the up-flow anaerobic sludge blanket (UASB) treatment of methanolic wastewater. The effect of amino acid-rich FS was evaluated through repeated batch tests, showing that a 0.5% and 1% dosage increased the maximum methane production rate by 93.60% and 123.04%, respectively, by promoting faster methanol degradation. Additionally, long-term operation of the UASB reactor was conducted with increased dosages of amino acid-rich FS, resulting in improved performance. Microbial community analysis demonstrated that the addition of amino acid-rich FS enhanced microbial diversity, with the abundance of Sporomusa increasing by 47.5 times. Beyond the original cooperative relationships, an additional synergy between Sporomusa and Methanosarcina was observed. These findings could address the key challenge of limited microbial diversity in the anaerobic treatment of methanolic wastewater.

Significant enhancement of biomethane recovery in up-flow anaerobic sludge blanket reactor treating starch wastewater through oyster shells conditioning

The up-flow anaerobic sludge blanket (UASB) reactor for treating starch wastewater exhibits poor resistance to organic loading rate shocks and low efficiency in biomethane recovery. This study proposed a solution to address this issue by using oyster shells as an alternative conditioner. Results indicated that the UASB reactor with oyster shells conditioning exhibited a significant increase in methane production from 243 to 435 mL/g-chemical oxygen demand (COD)removed, as the organic loading rate increased from 2.5 to 7.1 kg-COD/(m3·d). This value surpassed that of the control reactor, which experienced a sharp decline in performance. Furthermore, it also exceeded the majority of reported methane yields ranging from 150 to 330 mL/g-CODremoved. The pH adjustment and additional supply of carbon dioxide from oyster shells was primarily responsible for the substantial increase in methane production. Moreover, oyster shell conditioning also resulted in improvements in specific methanogenic activity, extracellular polymeric substances protection, and settling capacity of anaerobic granular sludge, as well as the enrichment in Methanosaeta abundance, and strengthening of methanogenic functional activity. All these factors contributed to the successful methanogenesis of starch wastewater in UASB reactor through oyster shell conditioning. These findings highlighted the potential of using oyster shells as a favorable conditioner for optimizing UASB treatment of easily acidified wastewater (e.g., starch wastewater), which presented promising practical applications.

Dissolved organic matter composition and microbial community dynamics in two-phase multi-staged up-flow anaerobic sludge blanket treatment of tapioca starch processing wastewater

The molecular changes in complex dissolved organic matter and the microbial community structure in a laboratory-scale two-phase multi-staged up-flow anaerobic sludge blanket (MS-UASB) system were determined by unknown screening analysis with Orbitrap mass spectrometry and next-generation sequencing using the Illumina® Miseq platform. The acidification (AC) reactor selectively decomposed less oxidized molecules and produced more oxidized compounds with less alkylated groups (lower number of CH2 groups). Subsequently, the MS-UASB removed a wide range of CHO moieties and effectively biodegraded the compounds produced by the AC reactor. However, longer CH2-chain compounds were observed. The retained sludge obtained from the MS-UASB reactor under different operating conditions revealed the dominance of the genus Methanosaeta (an acetoclastic methanogen) in the archaeal community. In addition, the distribution of the microbial community structures of the retained sludge and floating sludge differed when the MS-UASB reactor was unstable.

Up-flow anaerobic sludge blanket treatment of swine wastewater: Effect of heterologous and homologous inocula on anaerobic digestion performance and the microbial community

The effects of heterogenous (anaerobic sludge from treating distillery sewage, ASDS) and homologous (anaerobic sludge from treating swine wastewater, ASSW) inocula on anaerobic digestion and the microbial community in an up-flow anaerobic sludge blanket treating swine wastewater were compared. The highest chemical oxygen demand removal efficiencies with ASDS (84.8%) and ASSW (83.1%) were obtained with an organic loading rate of 15 kg COD/m3/d. For ASSW compared with ASDS, methane production efficiency was 15.3% higher and excess sludge production was 73.0% lower. The abundance of the cellulose hydrolyzing bacterium Clostridium sensu stricto_1 with ASDS (36.1%) was 1.5 times that with ASSW, while that of Methanosarcina with ASSW (22.9%) was > 100 times that with ASDS. ASDS reduced the content of pathogenic bacteria by 88.0%, while ASSW maintained a low level of pathogenic bacteria. ASSW greatly improved the methane production efficiency of wastewater and is more suitable for treating swine wastewater.

Modeling and optimization of an upflow anaerobic sludge blanket (UASB) system treating blackwaters

In the present work, a novel mathematical dynamic model describing the upflow anaerobic sludge blanket (UASB) has been developed. The model incorporates both the biological processes and the transport of sludge particles specifically related to the UASB treatment of blackwater. The processes occurring in the reactor are modeled as a sequence of two completely-mixed reactive tanks, one representing the sludge bed where most solids concentrate and the other representing a less solid-concentrated liquid volume. Solids from the sludge bed are assumed to be dragged to the upper zone of the reactor by the methane gas produced. The time variation of the sludge bed volume is included by assuming a constant sludge density. The model is calibrated against published data obtained from a stable operation of a lab-scale UASB system treating at different organic loading rates blackwater collected from real vacuum toilets. Good model prediction compatibility with the measurements of emitted biogas and methane gas flow rates, effluent COD, volatile fatty acids, pH and sludge bed volume was revealed. Furthermore, the model was successfully validated against another independent set of data from a UASB reactor treating a more diluted type of blackwater collected from conventional toilets. A scenario analysis performed using such a validated model reveals higher methane production yield but also higher effluent COD concentration at increasing organic loading rates and sludge bed volumes. It is found that longer HRTs can improve COD removal efficiency and methane production in blackwater treatment processes.

Removal of denatured protein particles enhanced UASB treatment of oxytetracycline production wastewater

Enhanced hydrolysis, which can selectively destroy antibiotic potency, has been previously demonstrated to be an effective pretreatment technology for the biological treatment of antibiotic production wastewater. However, full-scale application of enhanced hydrolysis to the treatment of real oxytetracycline production wastewater showed that the up-flow anaerobic sludge blanket (UASB) reactors treating the pretreated wastewater could only be stable under a low organic loading rate (OLR) of 1.8 ± 0.4 g·COD/L/d. Deterioration of UASB was also confirmed in treating the same wastewater using a bench-scale reactor (R1) at an OLR of 4.4 ± 0.3 g·COD/L/d. Assuming that the particles formed due to the denaturation of soluble proteins under the hydrolysis temperature (110 °C), resulting in the significant increase of suspended solids (SS) in oxytetracycline production wastewater from less than 200 mg/L to 1200 ± 500 mg/L, were responsible for the deterioration of UASB, the pretreated wastewater was filtered using polypropylene cotton fiber and ultrafiltration membrane, and then fed into two parallel bench-scale UASB reactors (R2 and R3). Both reactors maintained a stable COD removal (53.2% ~ 61.1%) even at an OLR as high as 8.0 g·COD/L/d. When the feed of R3 was switched to unfiltered wastewater, however, deterioration of the reactor occurred again. Microscopic observation showed that the granules in R3 were fully covered by protein particles after the switch of the feed. It was possible that the tight layer of the denatured protein particles blocked the inner pores of the granules, resulting in the obstruction of substrate transfer and biogas emission, while removing the protein particles could abate such blockage problem. This study provides a scientific basis for the efficient treatment of antibiotic production wastewater.

Heavy Metals in Sludge Produced from UASB Treatment Plant at Mirzapur, India

In Mirzapur (U.P.), a power-starved district, the UASB (Upflow Anaerobic Sludge Blanket) technique was adopted. Almost all of the available technologies do not treat heavy metals, so, is the case with the UASB also. The present study is to assess how much heavy metal can get accumulated in plant tissues in different species. The result of the present study was that the concentration of Pb(1106.31)>Zn(221.45)>Cd(49.26)>Hg(23.37) mg/Kg in the sludge while the concentration of Zn(93.35)>Pb(52.00)>Hg(16.93)>Cd(1.53) mg/Kg in the soil. When the sludge was mixed with the soil the trend got changed and the trend was Pb(596.36)>Zn(219.86)>Cd(24.70)>Hg(22.63) mg/Kg. Three different species that were chosen for the study were Basella Alba (Spinach), Solanum Lycopersicum (Tomato) & Brassica Juncea (Mustard). The trend of accumulation of studied heavy metals in the Brassica Juncea (Mustard) was Zn(85.33)>Pb(25.88)>Hg(11.23)>Cd(0.99) mg/Kg. In Solanum lycopersicum (Tomato) the trend was Pb(231.11)>Zn(108.72)>Hg(12.43)>Cd(9.41) mg/Kg and in Basella alba (Spinach) was Zn(103.81)>Pb(83.90)>Hg(10.78)>Cd(4.18) mg/Kg. Overall the study reveals that the accumulation of heavy metals takes place in plants grown in soil mixed with sewage sludge. The reduction in the concentration of Pb, Cd, Hg and Zn in sludge mixed with soil after the harvesting of plant in case of Solanum lycopersicum were 39.38%, 47.93%, 6.18% and 49.89% respectively; while in case of Basella alba these were 25.23%, 57.53%, 71.58% and 49.16% respectively; and in case of Brassica Juncea these reduction were 25.86%, 60.80%, 70.96% and 49.04% respectively.

Calcium phosphate granules formation: Key to high rate of mesophilic UASB treatment of toilet wastewater

Toilet wastewater, a rich source of organic matter and nutrients, can be treated anaerobically to recover energy and resources at mesophilic conditions (35 °C) using an upflow anaerobic sludge blanket (UASB) digester. However, low organic loading rates (OLR) have often been reported, which may be attributed to the flocs biomass applied in previous studies. In the present study, CaP granules were developed in the UASB reactor during the reactor operation of 250 days, which accounted for 89.2% of the UASB sludge, and had high VSS (25.9 ± 0.3 g/L) and high methanogenesis rates (0.34 ± 0.04 g CH4-COD/(gVSS·d)). An OLR of 16.0 g/(L·d) and a hydraulic retention time (HRT) of 0.25 days, were achieved, with a total chemical oxygen demand (COD) removal rate of 75.6 ± 6.0%, and a methane production rate of 8.4 ± 0.9 g CH4-COD/(L·d). The efficiency of the hydrolysis of organic substrates ranged from 32.6 ± 2.8% to 43.4 ± 1.4%. Microbial community analysis revealed that syntrophic bacteria Syntrophus, together with diverse H2-utilizing methanogens, proliferated; and eventually resulted in a hydrogenotrophic dominant pathway in the UASB reactor. The performance, mechanism of CaP granule formation, and the application of the process were discussed in detail. The present paper provided insight of high rate biomethane production from anaerobic toilet wastewater treatment.

Deciphering the effect of sodium dodecylbenzene sulfonate on up-flow anaerobic sludge blanket treatment of synthetic sulfate-containing wastewater

Deciphering the effect of sodium dodecylbenzene sulfonate on up-flow anaerobic sludge blanket treatment of synthetic sulfate-containing wastewater

Decay of SARS-CoV-2 RNA along the wastewater treatment outfitted with Upflow Anaerobic Sludge Blanket (UASB) system evaluated through two sample concentration techniques

For the first time, we present, i) an account of decay in the genetic material loading of SARS-CoV-2 during Upflow Anaerobic Sludge Blanket (UASB) treatment of wastewater, and ii) comparative evaluation of polyethylene glycol (PEG), and ultrafiltration as virus concentration methods from wastewater for the quantification of SARS-CoV-2 genes. The objectives were achieved through tracking of SARS-CoV-2 genetic loadings i.e. ORF1ab, N and S protein genes on 8th and 27th May 2020 along the wastewater treatment plant (106000 m3 million liters per day) equipped with UASB system in Ahmedabad, India. PEG method performed better in removing materials inhibiting RT-qPCR for SARS-CoV-2 gene detection from the samples, as evident from constant and lower CT values of control (MS2). Using the PEG method, we found a reduction >1.3 log10 reduction in SARS-CoV-2 RNA abundance during UASB treatment, and the RNA was not detected at all in the final effluent. The study implies that i) conventional wastewater treatment systems is effective in SARS-CoV-2 RNA removal, and ii) UASB system significantly reduces SARS-CoV-2 genetic loadings. Finally, PEG method is recommended for better sensitivity and inhibition removal during SARS-CoV-2 RNA quantification in wastewater.

Temperature effects on the methanogenesis enhancement and sulfidogenesis suppression in the UASB treatment of sulfate-rich methanol wastewater

This study aims at investigating that the temperature effects on the overall organics removal capability and the reaction kinetic properties of methanogenesis/sulfidogenesis in anaerobic treatment of sulfate-rich methanol wastewater. A lab-scale upflow anaerobic sludge blanket (UASB) reactor was operated for 285 days treating sulfate-rich methanol wastewater at a temperature range of 17.5–50 °C. The COD/SO42− ratio of synthetic wastewater is 0.5. Experimental results indicate that both methanogens and sulfidogens showed lower metabolic activities at 17.5–25 °C. The average chemical oxygen demand (COD) removal efficiencies were higher than 90% at 40–50 °C. During these experimental periods, larger than 85% of influent COD was confirmed to be utilized for methanogenesis, revealing that methanogens prevailed over sulfidogens and dominated significantly in the COD utilization. In contrast, the sulfidogenesis-based COD utilization was effectively limited under the temperature range of 40–50 °C.

A Single-Granule-Level Approach Reveals Ecological Heterogeneity in an Upflow Anaerobic Sludge Blanket Reactor.

Upflow anaerobic sludge blanket (UASB) reactor has served as an effective process to treat industrial wastewater such as purified terephthalic acid (PTA) wastewater. For optimal UASB performance, balanced ecological interactions between syntrophs, methanogens, and fermenters are critical. However, much of the interactions remain unclear because UASB have been studied at a “macro”-level perspective of the reactor ecosystem. In reality, such reactors are composed of a suite of granules, each forming individual micro-ecosystems treating wastewater. Thus, typical approaches may be oversimplifying the complexity of the microbial ecology and granular development. To identify critical microbial interactions at both macro- and micro- level ecosystem ecology, we perform community and network analyses on 300 PTA–degrading granules from a lab-scale UASB reactor and two full-scale reactors. Based on MiSeq-based 16S rRNA gene sequencing of individual granules, different granule-types co-exist in both full-scale reactors regardless of granule size and reactor sampling depth, suggesting that distinct microbial interactions occur in different granules throughout the reactor. In addition, we identify novel networks of syntrophic metabolic interactions in different granules, perhaps caused by distinct thermodynamic conditions. Moreover, unseen methanogenic relationships (e.g. “Candidatus Aminicenantes” and Methanosaeta) are observed in UASB reactors. In total, we discover unexpected microbial interactions in granular micro-ecosystems supporting UASB ecology and treatment through a unique single-granule level approach.

Recovery and biological oxidation of dissolved methane in effluent from UASB treatment of municipal sewage using a two-stage closed downflow hanging sponge system

A two-stage closed downflow hanging sponge (DHS) reactor was used as a post-treatment to prevent methane being emitted from upflow anaerobic sludge blanket (UASB) effluents containing unrecovered dissolved methane. The performance of the closed DHS reactor was evaluated using real municipal sewage at ambient temperatures (10–28 °C) for one year. The first stage of the closed DHS reactor was intended to recover dissolved methane from the UASB effluent and produce a burnable gas with a methane concentration greater than 30%, and its recovery efficiency was 57–88%, although the amount of dissolved methane in the UASB effluent fluctuated in the range of 46–68 % of methane production greatly depending on the temperature. The residual methane was oxidized and the remaining organic carbon was removed in the second closed DHS reactor, and this reactor performed very well, removing more than 99% of the dissolved methane during the experimental period. The rate at which air was supplied to the DHS reactor was found to be one of the most important operating parameters. Microbial community analysis revealed that seasonal changes in the methane-oxidizing bacteria were key to preventing methane emissions.

Anaerobic/aerobic treatment of greywater via UASB and MBR for unrestricted reuse.

The aim of the present study was to investigate the efficiency of integrated up-flow anaerobic sludge blanket (UASB) as anaerobic system followed by membrane bioreactor (MBR) as aerobic system for the treatment of greywater for unrestricted reuse. Pilot-scale UASB and MBR units were installed and operated in the NRC, Egypt. Real raw greywater was subjected to UASB and the effluent was further treated with microfiltration MBR. The necessary trans-membrane pressure difference is applied by the water head above the membrane (gravity flow) without any energy input. The average characteristics of the raw greywater were 95, 392, 298, 10.45, 0.4, 118.5 and 28 mg/L for total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphates, nitrates, oil and grease, and total Kjeldahl nitrogen (TKN), respectively. The pH was 6.71. The UASB treatment efficiency reached 19.3, 57.8, 67.5 and 83.7% for TSS, COD, BOD5 and oil and grease, respectively. When the UASB effluent was further treated with MBR, the overall removal rate achieved 97.7, 97.8, 97.4 and 95.8% for the same parameters successively. The characteristics of the final effluent reached 2.5, 8.5, 6.1, 0.95, 4.6 and 2.3 mg/L for TSS, COD, BOD, phosphates, oil and grease and TKN, respectively. This final treated effluent could cope with the unrestricted water reuse of local Egyptian guidelines.

UASB treatment of chemical synthesis-based pharmaceutical wastewater containing rich organic sulfur compounds and sulfate and associated microbial characteristics

• Successful application of UASB in treatment of rich organic S-bearing wastewater. • Sulfate in effluent was higher than influent at COD/SO 4 2− ratio of 8 and 5. • Conversely, sulfate in influent was higher than effluent at COD/SO 4 2− ratio of 1.5. • Archaea and bacterial community varied greatly with altered OLR. • Some species can be responsible for S release from organic sulfur compounds. The feasibility of treating of chemical synthesis-based pharmaceutical wastewater containing rich organic sulfur compounds and sulfate using an upflow anaerobic sludge blanket (UASB) was investigated. The initial COD/SO 4 2 − ratio of 8 in the wastewater varied from 5 to 1.5 after adding sulfate. Of interest that under the condition of COD/SO 4 2 − at 8 and 5, despite the simultaneous generation of sulfide and hydrogen sulfide, the sulfate concentration in the effluent was higher than in the influent. This is due to the sulfur release in the form of sulfate during the degradation of these organic sulfur compounds in this reactor. Conversely, at COD/SO 4 2 − of 1.5, influent sulfate was higher than effluent sulfate due to reduction of more sulfates in the reactor. At COD/SO 4 2 − of 8, for practical application, the optimum OLR was found to be 8 kg COD/m 3 /d, where a nearly 70% COD reduction occurred with biogas containing 63% methane. In this stage, the distribution of the archaea and bacterial community varied greatly with altered OLR (accompanied with prolonged operation time). Some species, such as Lysinibacillus sphaericus , Clostridium cellulovorans were expected to be partly responsible for S release from some organic sulfur compounds in the reactor. By increasing the sulfate loading at a COD/SO 4 2 − ratio up to 1.5 resulted in a light inhibition of methanogenesis due to the high sulfide concentration (1212 SO 4 2 − – S mg/L) with no obvious suppression of sulfidogenesis.

Treatment of Sweet Potato Starch Wastewater with UASB

A pilot-scale upflow anaerobic sludge blanket (UASB) reactor was used to study the sweet potato starch wastewater treatment performance and its influencing factors. Under normal temperature conditions, the operating parameters of sweet potato starch wastewater from UASB treatment was optimized, and the better conditions from different influent CODcr concentrations was obtained. The impacts from trace elements MgCl2, FeCl2, CoCl2, NiCl2 on physiological and biochemical characteristics of anaerobic granular sludge was developed.

Exploration of water-recycled cassava bioethanol production integrated with anaerobic digestion treatment

Due to the limited success of discharge target-hitting treatment in coping with environmental pollution from the alcohol industry, our attention was directed towards the distillery spent (DS) wash recycle in a cleaner bioethanol production by integrating anaerobic digestion treatment with conventional fermentation. An anaerobic digestion effluent from an alcohol waste water treatment plant is applicable for single use in ethanol fermentation. With further experimental estimate, the recycle of DS treated by a sole thermophilic up flow anaerobic sludge blanket (UASB) treatment was adverse to ethanol fermentation, resulting in a gradual increase of the residual total sugar from 1.2% at batch 1 to 8.0% at batch 5 after 48 h. With a combination of the thermophilic and mesophilic UASB treatment, the thirteenbatch fermentation recycling its DS achieved ~10.5% of ethanol production and > 90% of starch utilization after 48 h, which was comparable to that using tap water. This revealed a potential of the anaerobic digestion treatment in water-saving and emission reduction for bioethanol industry. Key words : Anaerobic digestion, cassava, cleaner bioethanol production, distillery spent wash, thermophilic and mesophilic up flow anaerobic sludge blanket, recycle and reuse.

Profiling and monitoring of DOM in brewery wastewater and treated wastewater

Dissolved organic matter (DOM) in raw and treated wastewater from two breweries in Thailand was profiled and monitored for the purpose of water reclamation. The wastewater and the effluent from the use of an upflow anaerobic sludge blanket (UASB) and activated sludge (AS) were collected and analyzed through a resin fractionation method using the fluorescent excitation-emission matrix (FEEM) technique. The results revealed that the major organic fractions in the brewery wastewater were hydrophobic acid (HPOA) and hydrophilic base (HPIB), accounting for 65% of total dissolved organic carbon (DOC) mass for brewery A and 56% of total DOC mass for brewery B. The FEEM results indicated that the organic matter in the wastewaters of both breweries were mainly composed of tryptophan-like substances, represented by peaks C (230 nm(Ex)/340-365 nm(Em)) and D (265-295 nm(Ex)/315-390 nm(Em)), and humic-like substances, represented by peaks E (290 nm(Ex)/400 nm(Em)), F (330-335 nm(Ex)/395-410 nm(Em)), and G (255-265 nm(Ex)/435-455 nm(Em)). The analysis revealed that the reduction of DOM occurred mostly during the UASB treatment where most of the DOM reduction resulted from the removal of the HPOA and HPIB fractions. The HPOA fraction, a group of humic-like substances, is of particular concern when reclaiming treated brewery wastewater, and although it was reduced by more than 80% of its initial amount, it was still a dominant DOM fraction in the effluents.

UASB treatment of a highly alkaline fruit-cannery lye-peeling wastewater

Anaerobic treatment of a highly alkaline fruit-cannery lye-peeling wastewater was investigated, using an upflow anaerobic sludge blanket (UASB) reactor. Only a short initialisation period was required before COD reduction and OLR had stabilised at 85 to 90% and 2.40 kgCODEm-3Ed-1, respectively. With subsequent increases in OLR to 8.1 kgCODEm-3Ed-1, the COD reduction remained between 85 and 93% and biogas production peaked at 4.1 .Ed-1 (63% methane). COD and reactor pH started to decrease after 111 d. Decreases in gas production were observed by Day 102, decreasing to 2.48 .Ed-1 by Day 111 and 0.93 .Ed-1 after 129 d. Subsequent reductions in the OLR, by reducing influent COD, had no effect on reactor stability. Loss of reactor performance was ascribed to the accumulation of sodium (potentially > 20 000 mgE.-1) within the reactor biomass, leading to inhibition of methanogenesis.

Effect of Volatile Fatty Acid Composition on Upflow Anaerobic Sludge Blanket (UASB) Performance

The effects of organic loading rates (OLRs) and volatile fatty acid (VFA) composition on upflow anaerobic sludge blanket (UASB) reactors were investigated. Four 2.5 L UASB reactors were fed by mixed VFA of 20 g of chemical oxygen demand (COD) L−1 initially and subsequently fed with different VFA compositions. In the initial stage of the experiment where the reactors were operated at an OLR between 0.82 and 10.4 g of COD L−1 day−1 with the substrate composed of a mixed acetate/propionate/butyrate composition, the COD removal efficiencies were in the range of 83 and 99% and the calculated methane yield ranged between 112 L of CH4 and 322 L of CH4 per g of COD removed. The result indicated that a higher methane yield corresponded with the increase of the OLR in the UASB treatment of the mixed VFA substrate. Mixed VFA-fed sludge showed a rather high activity in pure acetate and butyrate than pure propionate in a specific methanogenic activity (SMA) test. As the substrate composition changed from the mixed VFA...