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The main objective of this study was to evaluate the applicability and performance of a non-woven fabric filter designed as a biological post-treatment for an upflow anaerobic sludge blanket (UASB) reactor in wastewater treatment, with a specific focus on nitrification. The filter was set up to operate intermittently with a downward flow. It was constructed using polyvinyl chloride pipe with a diameter of 100 mm and a total height of 2 m. The filter medium comprised multiple non-woven fabric layers in discs forms, totaling 30 cm height, and covering the entire diameter of the reactor. Two distinct application rates were assessed in two phases: Phase I with a flow rate of 6 L·day−1 and an applied surface load of 0.76 m3·m−2·d−1 and Phase II with a flow rate of 9 L·day−1 and applied surface load of 1 m3·m−2·d−1. Chemical characterization was conducted on the influent and effluent of the filter, and quantification of nitrifying bacteria (ammonia-oxidizing bacteria [AOB] and nitrite-oxidizing bacteria [NOB]) was also performed. The results indicate that the average pH values of the effluent for both phases remained similar to the influent, at approximately eight, indicating that the flow rate difference did not significantly affect pH. However, significant alkalinity consumption was observed in both phases, with an average variation between influent and effluent of 186 (28%) and 169 mgCaCO3L−1 (31%) for Phases I and II, respectively. Ammonium nitrogen reduction was substantial: Phase I achieved 36% ammonia removal, with nitrite concentrations of 9.8 mgN.L−1 and nitrate concentrations of 13.7 mgN.L−1. Phase II achieved 54% ammonia removal, with nitrite concentrations of 2.1 mgN.L−1 and nitrate concentrations of 3.7 mgN.L−1. Regarding the quantification of AOB resulted in most probable numbers (MPN) of 8.3 × 105 and 1.6 × 108 per 100 mL, for Phases I and II, respectively. NOB were quantified at 2.5 × 103 MPN·100 mL−1 during the second phase. The findings demonstrate the potential of non-woven fabric filter as an effective post-treatment option for UASB reactor effluent, improving the quality of treated wastewater by physically removing organic products and enhancing nitrification processes. [ABSTRACT FROM AUTHOR]

Anaerobic co-digestion (AcoD) may be an interesting option to improve the operating conditions of anaerobic reactors used in vinasse treatment and provide an alternative for dairy cattle wastewater (DCW) management in regions near to ethanol industries. This work aimed to evaluate the effect of AcoD of sugarcane vinasse with DCW (84.8% and 15.2% of COD, respectively) in two up-flow anaerobic sludge blanket reactors (UASB—R1 and R2) in series. The improvements in the nutritional conditions of the vinasse because of the co-digestion with the DCW, combined with effluent recirculation, provided average removals of total COD of 77% for the overall system (R1 + R2) and volumetric methane production of 0.451 m3 CH4 (m3 d)−1 for R1. From the theoretical potential of electrical power production, we verified the possibility of producing 10.65 kWh d−1 per m3 of vinasse in the UASB reactors. That is 39% of the electrical energy needed to process one ton of sugarcane. Therefore, anaerobic co-digestion is an attractive alternative for energy use and reducing environmental problems of vinasse and DCW. [ABSTRACT FROM AUTHOR]

Vinasse is one of the major sources of environmental pollution because of high organic matter and toxic compound levels (e.g., sulfates and phenols). The more the vinasse treatment is, the less the environmental pollution will be. This study aimed to evaluate the effect of a low-cost and simple anaerobic pretreatment on the COD removal efficiency of the UASB reactor for the treatment of synthetic vinasse. In addition, this system was evaluated through organic loading rate (OLR), hydraulic retention time (HRT), upflow velocity (Vup), mixed liquor volatile suspended solid (MLVSS), mixed liquor suspended solids (MLSS), and pH. In a 155-day trial, the system was fed by synthetic vinasse with an organic loading rate (OLR) ranging from 2.5 to 20.5 kgCOD/m³.d. The results indicated that when a UASB reactor was used for synthetic vinasse treatment, the average COD removal efficiency and methane production were about 80.45% and 56%, respectively. However, the use of an anaerobic unit as a less expensive and simple pretreatment increased COD removal efficiency to 88.4% and methane production to 62.5% (684.6 L/kgCOD). The study result suggested that anaerobic pretreatment is suitable for reducing the environmental pollution of vinasse and can be used as an economical system for real vinasse treatment on an industrial scale. [ABSTRACT FROM AUTHOR]

Sulfate is of great importance in anaerobic digestion as its addition can help control the microbial community. In this study, the effect of sulfuric acid addition on the performance of a UASB reactor fed with hydrolyzed starch was investigated. The total organic carbon (TOC), Fe, SO42− removal and methane production were monitored under various chemical oxygen demand (COD) to SO42− ratios, hydraulic retention times (HRTs) and organic loading rates (OLRs). When the HRT was 16 h, and the OLR was equal to 2 g COD/LUASB-day, methane production was 0.24 L CH4/LUASB-day. After the addition of sulfuric acid, TOC removal reached 95%, and the population of Ruminococcus sp. that utilize soluble carbohydrates increased by 19.7%. Nitrogen removal was less than 25%, while the population of Ignavibacterium sp. accounted for 2.3%. When the HRT, OLR and COD/SO42− ratios were equal to 16 h, 2 g COD/LUASB-d and 3.72, respectively, methane production was 0.267 L CH4/LUASB-day. When the OLR increased to 5.94 g, the COD/LUASB-day and COD/SO42− ratios were equal to 12.5, and methane production was three times higher (0.84 L CH4/LUASB-day), with a methane content in the produced biogas greater than 70% due to the increased amount of Methanosaeta sp. and direct interspecies electron transfer. Sulfate addition increased the relative abundance of Desulfovibrio sp., accounting for 9.9% and an iron accumulation exceeding 98.0%. This study indicates that appropriate sulfate concentrations in the feed in combination with the presence of iron in the UASB lead to enhanced methane yields. [ABSTRACT FROM AUTHOR]

The paper presents the treatment of atrazine-contaminated wastewater by ozonation followed by an anaerobic process using Upflow Anaerobic Sludge Blanket (UASB) reactor. The experiment was performed with 100 ppb synthetic solutions of atrazine prepared in ultra-pure water. The corresponding initial Chemical Oxygen Demand (COD) is 226 mg.L-1. The initial pH was adjusted to 9.5. The atrazine-bearing synthetic wastewater was ozonated with an ozone dose of 9.4mg/l for 40 minutes of optimum ozonation time, resulting in a 35% reduction in the initial concentration of atrazine. Along with atrazine reduction, there was a COD removal of 54.42%. Further, it was degraded with an anaerobic process, resulting in the final reduction in atrazine concentration of 81% and the corresponding removal in COD of 86.7%. The process of ozonation led to the mineralization of atrazine and enhancement in the biodegradability of the wastewater. Using ion chromatography, the ozonated wastewater sample was analyzed for ionic by-products before and after ozonation. The ion chromatography results showed the breaking of the atrazine compound and the formation of Cl-, NO3-, SO42-, and and F- as intermediate products. Further, the BOD5/COD ratio increased, reflecting the increased biodegradability. This ozonated wastewater was treated in a UASB reactor where the pesticide was degraded to 19 ppb, and COs degraded to 30 mg.L-1. The overall removal of atrazine pesticide and COD were 81% and 86.7%, respectively, in the integrated system of ozonation followed by anaerobic degradation. [ABSTRACT FROM AUTHOR]

The upflow anaerobic hybrid (UAHB) reactor combines the advantages of a upflow anaerobic sludge blanket (UASB-type) reactor and an anaerobic filter in a single compartment. A novel configuration of the UAHB reactor, composed of two three-phase separators (3PHS), was proposed to evaluate the biogas production in the moving and fixed bed in the treatment of synthetic sewage at a temperature range of 14–21 °C and hydraulic retention time (HRT) of 12, 10 and 8 h. The bench-scale reactor was operated in three different phases with organic loading rate (VOLR) of 0.6 (0.3–0.7), 0.7 ± 0.2, and 1.1 ± 0.1 kg COD m−3 d−1, respectively, for 225 days. The average removal efficiency of chemical oxygen demand (CODt) was 78 (42–89)%, and the total biogas yield was 3090 (1704–4782) mL d−1, with 66% of the lower 3PHS (moving bed) and 34% of the upper 3PHS (fixed bed). However, no significant difference was observed between the biogas yield on the 3PHS (p-value = 0.5048), thus confirming the influence of temperature in the biogas production. The average percentage of methane was 76 (60–82)% for both beds, and the filter media increased the production by 21%. Thus, it can be concluded that the fixed bed suppressed the instability of the moving bed regarding the biogas production and contributed to the final quality of the effluent. [ABSTRACT FROM AUTHOR]

This study evaluated energy recovery from an upflow anaerobic sludge blanket (UASB) reactor treating paper industry wastewater and the goodness of fit of the Mantis2 model (i.e., using version 6.5 of the GPS-X™ software platform) to biogas and the effluent total chemical oxygen demand (COD) data. The UASB reactor achieved stable performance, exhibiting high COD removal efficiency about 96% for COD/SO42− = 5.0 on average. Experimental findings also revealed up to approximately 300 L/kg-CODrem. biogas yield indicating no clear inhibition due to high sulfate content. Daily biomethane production corresponded to approximately 25 kWh total energy (electricity+heat) generation per 1 m3 of wastewater treated. The overall goodness of fit of the model was satisfactory, based on the relatively low absolute deviations of 6.0% and 12.7% from the measured data for effluent COD and biogas generation, respectively. Besides, the resulting effluent COD simulation yielded a coefficient of determination (R2) value of 0.7663 and a mean absolute error (MAE) of about 39 mg/L. In light of experimental and simulation findings, the lab-scale UASB reactor indicated satisfactory performance and substantial biogas generation which would further encourage full-scale implementations of these promising energy recovery technologies in paper industries. [ABSTRACT FROM AUTHOR]

Microbial shift and predominance profile of a mesophilic upflow anaerobic sludge bed (UASB) reactor treating lignocellulose-rich wastewater [i.e., paper industry effluent with 665 mg SO4−2/L and COD/SO4 = 2–8] was investigated using next-generation sequencing (NGS) technology in accordance with a mass balance determination on sulfur and organic compounds. Since paper producing industries generate wastewaters with high organic and sulfate concentrations, coexistence of microbial-especially of sulfur-reducing and methane-producing-communities and their interactions have been also searched out considering the impact on biogas yield (~ 0.16 L CH4/g CODremoved) and sulfate reduction (up to 82%). Analysis of the microbiomes by Illumina sequencing showed that Desulfovibrio spp. were the detected sulfate-reducing bacteria (SRB) coexisting with methane-producing archaea (MPA). Despite no evident inhibition of relatively high sulfate on biogas generation, predominance of Euryarchaeota decreased by nearly half and taxonomic classification revealed a shift of microbial population from aceticlastic (Methanosaeta) to hydrogenotrophic (Methanolinea) methanogens as operation continued probably due to their general tendency to dominate in stressed condition. Bacteroidetes, Firmicutes, and Proteobacteria (involving major SRB genera in the delta subclass) phyla had the highest ratios of relative abundances demonstrating the crucial role of their coexistence during the removal of the pollutants in lignocellulosic wastewaters. [ABSTRACT FROM AUTHOR]

Water pollution caused by improper treatment of acid mine drainage (AMD) is one of the most common problems encountered in the mining process. However, the traditional physical and chemical methods are expensive, and the additional products are difficult to treat. Therefore, seeking a simple and efficient treatment method has become the main challenge in solving AMD. In this study, the efficiency of sulfate removal using sulfate-reducing bacteria (SRB) based on the upflow anaerobic sludge blanket (UASB) reactor and the changes in the sludge microbial community structure before and after the reaction were studied. The properties of SRB, particularly their reducing effect, were studied. Results show that SRB had good reduction performance in the environment with pH 6.5 to 7.5. The best-reducing effect was achieved at 15% inoculum. Under different initial sulfate concentrations, the sulfate removal rate in the UASB reactor reached 80–90%. After the reaction, the species' community abundance was increased, and the species diversity was enhanced. These investigations are conducive to providing new ideas and methods for treating AMD and solving the high sulfate concentrations in AMD. [ABSTRACT FROM AUTHOR]

Wastewater management remains a major challenge in developing countries due to the lack of adequate infrastructure, making the need for economically viable and efficient technologies that can be sustained by emerging economies imperative. The upflow anaerobic sludge blanket (UASB) reactor represents an efficient and low-cost technology that produces by-products from which valuable resources can be recovered. This study assessed the energy recovery potential in the form of electricity from biogas and sludge by-products produced by a full-scale UASB reactor. Biogas production rate and composition were monitored to determine the biogas energy recovery potential. Dehydrated sludge from sludge drying beds was likewise quantified and characterised for its elemental composition, immediate composition, gross calorific value and net calorific value to estimate sludge energy recovery potential. The average daily biogas production was found to be 611 ± 275 Nm3/d, with 65% methane in the biogas output. Average sludge dry matter production was determined to be 358.24 TS kg/d. The net energy recovery potential was estimated to be 534.1 MWh/yr, 36% more than the yearly energy demand (392.7 MWh/yr) of the entire plant. Conservative energy recovery at a UASB-based municipal wastewater treatment facility could serve as a self-supply energy option to support its operations. [ABSTRACT FROM AUTHOR]

A lab-scale up-flow anaerobic sludge blanket (UASB) reactor was used for biogas production from the citrus juice process wastewater (CPWW). The volume of the reactor was 11.5 L. During 200 days of the reactor, the organic loading rate (OLR) value changed from 1.8-21.9 kgCOD./m3.d, upflow velocities (Vup) 0.1-5.2 m/h and hydraulic retention time (HRT) changed from 0.042 to 4.16 days. The reactor showed a stable performance at all organic loadings. Experimental chemical oxygen demand (COD) removal efficiencies were 71.5±21% and 83.3±16.3% for total COD (TCOD) and soluble COD (SCOD), respectively. The acetic acid concentration changed from 135 to 650 mg/L. The temperature was kept in the range of 35.1±1.4 oC, the pH in the range of 6.6±0.2, and the alkalinity was controlled daily and kept in the range of 411±273 CaCO3 mg/L. After anaerobic reactions, 6283±3476 m3/d biogas was produced and the methane concentration in the biogas was 65.5±11.5%. Depending on the methane production, the annual energy value potential that can be obtained from the existing UASB reactor is estimated as 48,768 kWh. [ABSTRACT FROM AUTHOR]

The present study investigates the potential of a novel upflow anaerobic sludge blanket (UASB) reactor with a built-in polishing facility for the treatment of municipal sewage. A laboratory-scale reactor, which combined an inner-centric hybrid UASB module and an outer concentric downflow hanging sponge (DHS) unit, was designed and fabricated as a part of this research work. The reactor had been continuously operated for 210 days under ambient conditions. With anaerobically digested sewage sludge (seed sludge blended with Locust bean gum polymer) as inoculum, the reactor attained a successful startup in 40 days. Ensuring startup, the reactor was employed under varying organic loading rates (OLR) from 0.87 to 5.09 kg COD/m3/d, with corresponding hydraulic retention times (HRT) of 24–4 h. The novel UASB reactor made its mark with a high COD and TSS removal of 93.2% and 93%, respectively, under the optimum conditions of 6-h HRT. In addition, biogas rich in methane content (68%), with a maximum specific yield of 0.42± 0.02 m3 biogas /kg COD destroyed, was generated. The VSS/TSS ratio observed a steady rise (0.51 to 0.75) with increasing sludge age, bearing witness to the active growth of biomass. Hence, in brief, the novel UASB reactor can be coined as an energy economic system with improved effluent quality. [ABSTRACT FROM AUTHOR]

This paper study the performance of a lab-scale hybrid up-flow anaerobic sludge blanket (UASB) reactor treating low-strength synthetic wastewater using different biofilm supporting materials. Two identical reactors are constructed and operated at constant up-flow velocity of 0.1 m/hr., inflow rate of 9.76 L/d, and hydraulic retention time (HRT) of 8.26 hours. The Start-up phase, using seed sludge for existing wastewater treatment plant, lasted until the efficiency of chemical oxygen demand (COD) removal of both reactors reached 80%. Polyethylene (PE) media are added to one of the reactors and luffa sponge is used in the second reactor. Results show increased COD removal efficiency up to about 90% at 20 °C and biogas production rates from 3.8*10−3 till 7.5*10−3 m3 CH4/kg CODr using PE media. The COD removal efficiency reaches about 95% at 20 °C using luffa sponge and biogas production rates up to 6.5*10 −3 m3 CH4/kg CODr are achieved before clogging problem is observed. Effect of HRT reduction, from 8.26 to 4.13 hours, on removing clogging is investigated. Reduction in COD removal efficiencies is observed at low ambient temperatures during seasonal variations of 15–25 °C. AFM and SEM analysis are used to examine sludge granulation and biofilm formation. [ABSTRACT FROM AUTHOR]

Perchlorate ( ClO 4 − ) industrial wastewater requires efficient removal to prevent adverse environmental impacts, however, high concentration and low biodegradability give rise to poor ClO 4 − bioreduction performance. S 2 − -autotrophic granular sludge ( S 2 − -AuGS) was firstly cultivated for high concentration perchlorate ( ClO 4 − ) removal in the upflow anaerobic sludge blanket (UASB) reactor ( ClO 4 − : 150 mg L−1). Simultaneously, the S 2 − was utilized to control the SO 4 2 − generation as electron donor, the effluent SO 4 2 − concentration (190 mg L−1) was satisfied with drinking water standard (250 mg L−1). Under the optimized condition of hydraulic retention time (HRT) (6 h) and S 2 − / ClO 4 − molar ratio (2.2), more EPS was secreted, which promoted the S 2 − -AuGS formation and stability. Though acclimation of 146 d, the S 2 − -AuGS was formed with a large average granular sludge size (612 μm) and an excellent settleability (sludge volume index: SVI5/SVI30 = 1). With the mature S 2 − -AuGS formation, the highest ClO 4 − and S 2 − loading was increased to 1.06 and 0.75 kg m−3 d−1. Interestingly, Georgfuchsia, Methyloversatilis, Sulfurisoma, and Exiguobacterium were the main microbial community in the S 2 − -AuGS. This study proposed to form a novel S 2 − -AuGS for developing the high ClO 4 − concentration removal performance and to utilize the S 2 − as an electron donor for controlling the excessive SO 4 2 − generation. [ABSTRACT FROM AUTHOR]

Recent studies have focused on proposing materials with larger pores and lower cost to replace conventional membranes. This study aims to investigate the performance of an anaerobic dynamic membrane bioreactor (AnDMBR) at pilot scale, acting as a post-treatment for an Upflow Anaerobic Sludge Blanket (UASB) reactor treating sewage, for the removal of complementary organic matter, focusing on the module design, dynamic layer formation and process performance. The configurations tested on this study were: UASB followed by stone filter and three AnDMBRs in series with polyester pore sizes of 100 μm, 50 μm, and 5 μm; UASB followed by disc filter and the three AnDMBRs in series; UASB followed by the three AnDMBRs in series; and UASB reactor with only one AnDMBR module. Regarding the studied configurations, high removals of total suspended solids, chemical oxygen demand, and turbidity were achieved in all experimental setups. The use of stone and disc filters did not bring clear benefits to the system concerning the direct application of filtration with dynamic membranes, therefore, their removal in the system was favorable. The dynamic membrane formation was faster in the 50 μm mesh, and only a few hours were necessary to obtain a permeate quality with a total suspended solids concentration and a turbidity lower than 15 mg·L−1 and 30 NTU, respectively. Thus, the dynamic membrane technology proved to be a potential solution in the post-treatment of UASB reactor effluents. HIGHLIGHTS Dynamic membranes are promising alternatives for the post-treatment of UASB wastewater.; Polyester mesh pore sizes of 50 μm are an inert and low-cost material for the fabricate of dynamic membranes.;

[Display omitted] • 2 pilot-reactors treated settled wastewater at <20 °C with different seed-sludge. • Similar methane production and hydrolysis rates were measured in the UASB and AnMBR. • Hydrolytic enzymes (β-glucosidase, protease and lipase) were not psychrophilic. • Hydrolytic enzymes had higher affinity to substrates at the operational temp. <20 °C. • Effective adaptation of enzymes to <20 °C irrespective of seed-sludge source. Particulate matter hydrolysis is the bottleneck in anaerobic treatment of municipal wastewater in temperate climates. Low temperatures theoretically slow enzyme-substrate interactions, hindering utilization kinetics, but this remains poorly understood. β-glucosidase, protease, and lipase activities were evaluated in two pilot-scale upflow anaerobic sludge blanket (UASB) reactors, inoculated with different sludges and later converted to anaerobic membrane bioreactors (AnMBRs). Despite similar methane production and solids hydrolysis rates, significant differences emerged. Specific activity peaked at 37 °C, excluding the predominance of psychrophilic enzymes. Nevertheless, the Michaelis-Menten constant (Km) indicated high enzyme-substrate affinity at the operational temperature of 15–20 °C, notably greater in AnMBRs. It is shown, for the first time, that different seed sludges can equally adapt, as hydrolytic enzymatic affinity to the substrate reached similar values in the two reactors at the operational temperature and identified that membrane ultrafiltration impacted hydrolysis by a favourable enzyme Michaelis-Menten constant. [ABSTRACT FROM AUTHOR]

Poor wastewater management remains a critical health and environmental challenge in most developing countries in Sub-Saharan Africa due to the lack of adequate infrastructure for collection and treatment. This study evaluated the performance and methane production of a full-scale upflow anaerobic sludge blanket (UASB) reactor of capacity 18000 m3/d, with post-treatment unit: trickling filters followed by final settling tanks for municipal wastewater treatment in Ghana. Data was collected on operational conditions and physicochemical parameters of wastewater (influent and effluent) over a period of 35 weeks in 2021 (from January to August). The influent biochemical oxygen demand to chemical oxygen demand (BOD:COD) ratio was 0.58 ± 0.16, indicating the presence of highly biodegradable compounds in the sewage. Operational conditions for the UASB reactors were observed to be within the optimal range for anaerobic systems, with an applied organic loading rate of 1.30 ± 0.79 kgCOD/m3/d. Generally, Plant performance was satisfactory with carbon removal at 93% for COD and 98% for BOD. Biogas yield was 0.2 m3/kgCOD removed, culminating in an average biogas production rate of 831.6 ± 292.7 m3/d. Average methane composition was 64.7 ± 11.9% of the biogas output, whilst an estimated 35% of the methane generated remained dissolved in the UASB effluent. The UASB reactor presents an efficient technology that can be implemented in developing countries for effective and sustainable wastewater management.

[Objective] Biofuel ethanol is a kind of green energy, but on the process of production it produces a large amount of high concentration of organic wastewater. The traditional process of biological removal nitrogen has been unable to meet the requirements of high standard nitrogen removal in the production industry, thus we need to explore a new way of nitrogen removal, and screen out the best reaction conditions. [Method] In the present study, an improved upflow anaerobic sludge bed (UASB) reactor was used to treat biofuel ethanol wastewater, and the conditions suitable for the growth of ANAMMOX bacteria were controlled to achieve economic and efficient treatment of high nitrogen wastewater. The influent water in the start-up stage of ANAMMOX was self-supplied water. The concentration of ammonia nitrogen and nitrite nitrogen in the self-supplied water was gradually increased to explore the optimal range of nitrogen concentration during start-up. Once successful start-up and stable operation of the reaction, the secondary digested liquid of biofuel ethanol from production plant was pretreated as influent water. ANAMMOX reaction conditions were optimized by adjusting water pH and temperature, and the optimal range of pH and temperature were determined according to the actual production condition. [Result] A comprehensive analysis of the concentration of nitrogen, removal rate of nitrogen, total nitrogen reduction reaction (NRR) and loading rate (NLR) in the influent and effluent showed that ANAMMOX reaction started successfully after 70 days. At this stage, the maximum removal rate of ammonia nitrogen reached up to 97.8% and total nitrogen to 96.0%. When pH value was 7.5-8.0 and reaction temperature was 25-35 ℃, the nitrogen removal efficiency was better. In this range, the NRR and NLR complied with the equation y = 2158x-0.94 (R~2 = 0.995, P<0.01). [Conclusion] Controlling pH and reaction temperature in the optimal range can improve the requirement of efficient denitrification of industrial wastewater, which can be used to purify this kind of wastewater in production process. [ABSTRACT FROM AUTHOR]

In the production of natural rubber, formate or acetate is added to the latex solution to coagulate the rubber; therefore, the wastewater contains high concentrations of organic acids, requiring the application of anaerobic treatment technology. In this study, a two-phase continuous flow experiment using a laboratory-scale upflow anaerobic sludge blanket (UASB) was conducted to investigate the influence of formate inflow on the microbial and physical characteristics of the retained granular sludge. In phase 1, acetate-based wastewater was used as feed, while in phase 2, formate-based wastewater was used as feed. In phase 1, the UASB exhibited high COD removal efficiency (97.2%); in addition, the retained sludge showed increased methane production from acetate and proliferation of acetate-utilizing Methanosaeta species. In phase 2, the UASB performed as well as phase 1, with 98.2% COD removal efficiency. Microbial community structure analysis confirmed that relatives of Methanobacterium formicicum present in the retained sludge were responsible for the degradation of formate in phase 2. However, decreased diameter and slight deterioration of granular sludge settleability were observed. In conclusion, formate inflow has low risk of interference with the process performance of the UASB, but it has negative effects on the physical properties of the granular sludge. [ABSTRACT FROM AUTHOR]

The impact of climate change on water availability and quality has affected agricultural irrigation. The use of treated wastewater can alleviate water in agriculture. Nevertheless, it is imperative to ensure proper treatment of wastewater before reuse, in compliance with current regulations of this practice. In decentralized agricultural scenarios, the lack of adequate treatment facilities poses a challenge in providing treated wastewater for irrigation. Hence, there is a critical need to develop and implement innovative, feasible, and sustainable treatment solutions to secure the use of this alternative water source. This study proposes the integration of intensive treatment solutions and natural treatment systems, specifically, the combination of up-flow anaerobic sludge blanket reactor (UASB), anaerobic membrane bioreactor (AnMBR), constructed wetlands (CWs), and ultraviolet (UV) disinfection. For this purpose, a novel demo-scale plant was designed, constructed and implemented to test wastewater treatment and evaluate the capability of the proposed system to provide an effluent with a quality in compliance with the current European wastewater reuse regulatory framework. In addition, carbon-sequestration and energy analyses were conducted to assess the sustainability of the proposed treatment approach. This research confirmed that UASB rector can be employed for biogas production (2.5 L h−1) and energy recovery from organic matter degradation, but its effluent requires further treatment steps to be reused in agricultural irrigation. The AnMBR effluent complied with class A standards for E. coli , boasting a concentration of 0 CFU 100 mL−1, and nearly negligible TSS levels. However, further reduction of BOD 5 (35 mg L−1) is required to reach water quality class A. CWs efficiently produced effluent with BOD 5 below 10 mg L−1 and TSS close to 0 mg L−1, making it suitable for water reuse and meeting class A standards. Furthermore, CWs demonstrated significantly higher energy efficiency compared to intensive treatment systems. Nonetheless, the inclusion of a UV disinfection unit after CWs was required to attain water class B standards. • Combined up-flow anaerobic sludge membrane and constructed wetland can treat wastewater. • Final effluent was suitable for safe water reuse in agriculture. • Combination of intensive and natural solutions can lower energy consumption and overall costs. • Intermittent aeration of constructed wetlands was more beneficial compared to continuous one. • Disinfection unit or a membrane are necessary for effective pathogen removal. [ABSTRACT FROM AUTHOR]

In this work, the Upflow Anaerobic Sludge Blanket “UASB” reactor treated effluent wastewater to investigate the process performance on a pilot plant scale. Municipal wastewater at high and medium strength with different organic load rate OLR (0.6-9) kg COD m-3day-1 with the flow of 20 l/h, up-flow velocity 0.4 m/h, hydraulic retention time HRT 9 h at a temperature of (20-30 ºC) was evaluated. The wastewater concentration, including TSS, COD was measured, and the removal efficiencies of chemical oxygen demand (COD) and total suspended solid TSS were calculated and summarized as 45-85% and 70-75%, respectively, depending on organic load rate OLR. Effluent volatile fatty acids VFA was measured, and the results were in the range between 12-90 mg/L depending on OLR with a slight change in pH (8.3-8.4), which means the conversion of COD to methane and increase ammonia concentration.

This paper studied the effectiveness of a slaughterhouse wastewater treatment plant. The purpose of this study is to evaluate the slaughterhouse effluent treatment plant (SETP) in eliminating impurities, as well as the variables that affect performance. The SETP consisted of a dissolved air floatation (DAF) system with an up-flow anaerobic sludge blanket (UASB) reactor followed by two activated sludge processessing (ASP) stages. The removal efficiencies of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS) were 74.7%, 76.8%, and 90.14%, respectively. The study proposes constructing a tertiary treatment facility, installing two dung squeezers, and commissioning the UASB.

The upflow anaerobic sludge blanket (UASB) reactor can be considered as one of the promising anaerobic wastewater treatment technologies suitable for the treatment of high‐strength wastewater. In the recent period, researchers have focused on the treatment of low‐strength wastewater using this technology. This review focuses on the key factors affecting the reactor performance such as hydraulic retention time (HRT), temperature, organic loading rate (OLR), pH and alkalinity, granulation, wastewater characteristics, mixing, and modification to conventional configuration. Start‐up and granulation played a major role in the determination of reactor performance, and various theories have been proposed to understand the mechanism of granulation. Correlation between start‐up time and OLR was found to be low, as other operating parameters might have been influencing the start‐up time. Flowchart depicting the development of UASB reactor over time is included. In the present work, further development and derivatives of the UASB reactor such as static granular bed reactor (SGBR) and expanded granular sludge bed (EGSB) reactor are analyzed. The optimal conditions for UASB for treating various types of substrates was found to be HRT of 3–24 h, OLR of 1–15 kg COD/m3/d, and operational temperature in mesophilic range (30–40°C). Analysis of various modifications that pave the way for identification of future areas of research to improve reactor performance is also presented.The figure shows a schematic view of the conventional UASB reactor, and to improve the performance of the reactor, development of granules should be given more importance. To make the granules suitable for the reactor, start‐up has to be initiated. Furthermore, factors affecting performance of the reactor were also discussed. To improve the performance furthermore, various modifications of UASB by imposing variations in configuration were tried. It also shows schematic view of EGSBR and SGBR (derivatives of UASB).Practitioner Points: Governing factors for better operating conditions are presented.Attaining start‐up with respect to various substrates is discussed.Factors responsible for increase in efficiency, further developments and derivatives of UASB are depicted. [ABSTRACT FROM AUTHOR]

Several laccase-based products have been launched on the market over the years. However, there is little information about their toxicity and/or the toxicity of their residues. We evaluated the toxicity of a simulated denim-laundry wastewater containing Biolite BSN, a laccase-based product used for denim bleaching. The evaluation included a viability test with Saccharomyces cerevisiae, a phytotoxicity test with Sorghum vulgare, and a toxicity test with Daphnia magna. The viability of S. cerevisiae was reduced to 40%. The radicle and plumule growth of S. vulgare was reduced to 62 and 66%, respectively. The CL50 for D. magna was 29.7%, which classified this water as toxic (according to the percent rank method). Biolite BSN was identified as the main cause of the toxic effects; furthermore, the chemical oxygen demand (COD) of the wastewater was significantly high (3346.2 mg/L), and more than 90% of the COD corresponded to Biolite BSN. The anaerobic biodegradability tests showed that the denim-laundry wastewater could be treated anaerobically; therefore, it was treated in an upflow anaerobic sludge blanket (UASB) reactor. The treatment reduced the toxicity and COD in 50 and 77%, respectively, and a methane yield of 311.1 mL CH4/g of CODremoved was obtained. Based on these results, we recommend to analyze the toxicity of all textile chemicals, regardless of whether they are enzyme-based products. A UASB reactor can be used as the first treatment stage for similar effluents in order to reduce the COD and the toxicity and recover methane as an added benefit. [ABSTRACT FROM AUTHOR]

This work evaluated the UASB-septic tank performance using different kinetic models that correlated process efficiency and methane production with hydraulic and organic loading rates through experiments with five different HRT (48 h, 36 h, 24 h, 18 h, and 12 h) using synthetic domestic wastewater. The modified Stover-Kincannon model provided the best fitting to calculate kinetics constants, with an R2 above 98% for linear regression, and predicted the effluent COD more accurately than the other models. Methane yield was 0.3294 L CH4/g COD removed, being closer to the theoretical value, and the Van der Meer and Heertjes model had the highest R2 for methane production. Organic matter and solids removal were 45% for TS, 70% and 68% for total and soluble COD, and 85% for TSS. Pollutant removal markedly decreased when the reactor operated HRT below 24 h; thus, it is recommended to operate the UASB-septic tank at this HRT. [ABSTRACT FROM AUTHOR]

This experiment studied the effect of compound compatible solutes on the treatment of 20 g/L high-salt wastewater by UASB reactor anaerobic granular sludge. The results show that the primary and secondary order of each factor is organic load > influent pH > temperature > mixture ratio. When treating 20 g/L salinity wastewater with an influent COD concentration of 2 016 mg/L, the optimal reaction conditions are an organic load of 4 800 mg/ (L • d), the ratio of betaine, trehalose, glutamate, proline and potassium chloride is 120: 20: 25: 25: 1, and a temperature of 35°C, the pH of the inlet water is 8.6. The COD removal rate is 93. 4%, and the gas production rate is 1. 63 LI d. [ABSTRACT FROM AUTHOR]

Upflow Anaerobic Sludge Blanket (UASB) reactors are widely used for domestic sewage treatment in Brazil, and generate sludge and biogas as by-products. Typically, the sludge is sent to sanitary landfills, and the biogas is burned in flares. This study assessed the energy potential of these by-products in sewage treatment plants (STPs) located in the state of Paraná, Brazil. First, an overview of biogas energy recovery potential in a full-scale STP based on UASB reactors was carried out. Afterwards, a total of 239 STPs in the state of Paraná were assessed, and the energy potential of the by-products was estimated by a mathematical model. Data were spatially classified using ArcGIS®, taking into account the different effluent characteristics (worst, typical and best scenario), sludge dehydration systems (drying bed and centrifuge) and sizes (small, medium and large). Among the states in Brazil, Paraná presented the highest biogas potential, although nowadays it exploits only 0.4% of its capacity. Biogas was the main by-product generated by UASB reactors in Paraná, and if used in the entire state, it could supply the energy demands of a city with 111,000 inhabitants. Biogas corresponded to 65, 64 and 74% of the total potential (sludge and biogas) for small, medium and large STPs, respectively. The study of the energy potential of the by-products associated with GIS tools positively contributes to the decision-making process in sanitation management and to improve energy sustainability.

Artan nüfus ile birlikte tarım ve hayvancılık sektörleri üretim kapasitelerini arttırmışlardır. Böylece daha fazla atık oluşturan çiftlik ve tarım alanlarından kaynaklanan çevresel riskler de artmıştır. Hayvansal atıkların kontrollü bertaraf edilmemesi ve meralara, akarsulara, açık alanlara veya tarım alanlarına atılması önemli problemlere neden olmaktadır. Organik maddelerin stabilize olmaması nedeniyle, toprağın biyolojik yapısı bozulmakta ve böcek, sivrisinek ve koku problemleri sonucu çevre sağlığı tehdit edilmektedir. Hayvansal atıklardan kaynaklanan azot ve fosfor ayrıca yüzeysel suları etkilemekte ve yaşam döngüsüne zarar vermektedir. Oluşan atıksuların yarattığı çevresel sorunlardan yola çıkarak bu çalışma kapsamında, besi çiftliği atıksularının ardışık, anaerobik yukarı akışlı çamur yataklı reaktör (UASB) / aerobik sürekli karıştırmalı tank reaktörde (CSTR) arıtımı incelenmiştir. Anaerobik UASB reaktörün ardından kalan organik kirliliği parçalamak için aerobik CSTR reaktör kullanılmıştır. Sistemde farklı organik yükleme hızlarında (3.53-10.59 kgKOİ/m3gün) kimyasal oksijen ihtiyacı (KOİ) giderimi ve metan gazı miktarı ölçülmüştür. Çalışmada anaerobik UASB reaktörde en yüksek KOİ giderme verimine %90.3 olarak 7.06 kg KOİ/m3gün organik yükleme hızında ulaşılmıştır. Anaerobik arıtma kısmında oluşan biyogazda en yüksek ölçülen metan gazı oranı %65 olmuştur. Elde edilen sonuçlar besi çiftliği atıksularının ardışık anaerobik yukarı akışlı çamur yataklı reaktör/ aerobik sürekli karıştırmalı tank reaktörde arıtılabilirliğinin yüksek olduğunu göstermektedir. KOİ değerinin yüksek oluşu, bu tür atıksuların arıtımında anaerobik yöntemlerin kullanılmasının uygun olabileceğini göstermektedir.

Artan nüfus ile birlikte tarım ve hayvancılık sektörleri üretim kapasitelerini arttırmışlardır. Böylece daha fazla atık oluşturan çiftlik ve tarım alanlarından kaynaklanan çevresel riskler de artmıştır. Hayvansal atıkların kontrollü bertaraf edilmemesi ve meralara, akarsulara, açık alanlara veya tarım alanlarına atılması önemli problemlere neden olmaktadır. Organik maddelerin stabilize olmaması nedeniyle, toprağın biyolojik yapısı bozulmakta ve böcek, sivrisinek ve koku problemleri sonucu çevre sağlığı tehdit edilmektedir. Hayvansal atıklardan kaynaklanan azot ve fosfor ayrıca yüzeysel suları etkilemekte ve yaşam döngüsüne zarar vermektedir. Oluşan atıksuların yarattığı çevresel sorunlardan yola çıkarak bu çalışma kapsamında, besi çiftliği atıksularının ardışık, anaerobik yukarı akışlı çamur yataklı reaktör (UASB) / aerobik sürekli karıştırmalı tank reaktörde (CSTR) arıtımı incelenmiştir. Anaerobik UASB reaktörün ardından kalan organik kirliliği parçalamak için aerobik CSTR reaktör kullanılmıştır. Sistemde farklı organik yükleme hızlarında (3.53-10.59 kgKOİ/m3gün) kimyasal oksijen ihtiyacı (KOİ) giderimi ve metan gazı miktarı ölçülmüştür. Çalışmada anaerobik UASB reaktörde en yüksek KOİ giderme verimine %90.3 olarak 7.06 kg KOİ/m3gün organik yükleme hızında ulaşılmıştır. Anaerobik arıtma kısmında oluşan biyogazda en yüksek ölçülen metan gazı oranı %65 olmuştur. Elde edilen sonuçlar besi çiftliği atıksularının ardışık anaerobik yukarı akışlı çamur yataklı reaktör/ aerobik sürekli karıştırmalı tank reaktörde arıtılabilirliğinin yüksek olduğunu göstermektedir. KOİ değerinin yüksek oluşu, bu tür atıksuların arıtımında anaerobik yöntemlerin kullanılmasının uygun olabileceğini göstermektedir.

In developing countries, most of the daily produced household wastes are buried in landfill sites without any prior treatment. One of the many problems associated with these landfills is the formation of leachate. Because of its complexity and unpredictable composition, leachate has always constituted a challenging task for effluent managers. Despite the countless techniques that have been developed since then, leachate treatment still raises big concerns about the efficiency and sustainability of a suitable strategy. Accordingly, this study is carried out aiming at the optimization of leachate treatment through biostimulation using carob powder as a co-substrate. The added amount of biostimulant corresponds approximately to the addition of 3, 1, and 0.4 g/L of sucrose, fructose, and glucose, respectively. The adopted experimental system is based on the anaerobic process using an up-flow anaerobic sludge blanket (UASB) reactor, which was operated at HRT and OLR of 24 h and 26.1 kg COD/m3 d, respectively. For carob particle size larger than 2 mm, only a small amount of biogas was produced and the COD removal efficiency was lower than 77%, indicating that the poor quality of the effluent persists. However, 97% of COD was efficiently removed and a volume of 2.06 L/Lleachate of biogas was produced using a carob particle size of 0.250 mm. The obtained results showed also that the amount of produced biogas increases as the carob sugar content increases. Literally, a 1% fraction of total sugar content resulted in an increase of 17.9 mL/Lleahate of the produced biogas. Finally, the use of 10 g/L of carob amendment improved COD removal and exhibited less influence on syntrophs and methanogens since a large amount of biogas was generated. Article Highlights: Carob powder biostimulant could be effectively used to optimize leachate treatment. Carob particle size and total sugar content affected the treatment efficiency. Thinner the carob particles, larger the produced biogas and larger the COD removal. 1%-fraction of sugar content resulted in an increase of 17.9 mL/Lleahate of biogas. [ABSTRACT FROM AUTHOR]

Brazil is currently focused on its energy matrix transition in favor of increasing of the share of renewable energy carriers for both enhanced energy security and mitigation of greenhouse gas emissions. In this context, the country`s pulp and paper industry whose different wastes teams are not generally exploited, could play a critical role. Accordingly, the main objective of this work is to develop a conceptual ‘systemic’ biorefinery framework integrating the treatment of pulp and paper mill wastewater using upflow anaerobic sludge blanket (UASB) reactor with energy recovery through biogas production and its conversion into heat and power in stationary engines and boilers, respectively. Based on the results obtained through the present case study, it was revealed that the adoption of UASB reactors by the paper mill industry could properly addresses the environmental concerns faced while could contribute to the national agenda favoring an increasing share of renewable energies in the country`s energy matrix. The financial analysis showed that the investment required for the implementation of UASB reactors within a biorefinery platform would be minor vs. the investment in the whole mill and would be returned in 6.4 yr with a high return on investment even when operated at half of operational capacity. Moreover, through the developed UASB reactor-based biorefinery, the Brazilian pulp and paper industry as a whole could avoid 1.06 ×105 CO2eq tons, effectively contributing to the decarbonization of the country`s economy.

Three types of anaerobic granular sludge for treating chemical synthesis-based pharmaceutical wastewater were compared: (1) an up-flow anaerobic sludge blanket (UASB) filled with polyvinyl alcohol (PVA) gel beads (UASB-PVA); (2) a UASB filled with traditional anaerobic granular sludge; and (3) a UASB filled with traditional anaerobic granular sludge and granular active carbon (UASB-GAC). The domestication times for the UASB-PVA, UASB, and UASB-GAC reactors were 30, 47, and 47 days, respectively. When the organic loading rate (OLR) was up to 7 kg chemical oxygen demand (COD)/(m3·d), the COD efficiency of the UASB-PVA, UASB, and UASB-GAC stayed in the range of 69% to 75% (deviation 1.8%), 46% to 69% (deviation 8.6%), and 61% to 73% (deviation 4.0%), respectively. The highest OLRs reached for the UASB-PVA, UASB, and UASB-GAC were 12, 7, and 8 kg COD/(m3·d), respectively. The performance of the UASB-PVA was the best of the three, the UASB-GAC was second, and the UASB was the worst. High-throughput pyrosequencing analysis showed that Levilinea, Syntrophorhabdus, Desulfovibrio and Acetobacterium were the dominant bacteria in the UASB-PVA, UASB, and UASB-GAC reactors’ granular sludge. The abundance and diversity of the microbial community in the UASB-PVA sludge were higher than for the UASB and UASB-GAC granular sludge.

An up-flow anaerobic sludge bed (UASB) reactor was operated for five months to treat domestic wastewater contaminated by propylene glycol -main component of Type 2 aircraft deicing fluid (ADF)- at threshold ratio based on optimization study with batch reactors [i.e., operated at externally included ADF = 0.83–4.20%]. Biogas yields up to ~0.4 m3/kg CODinfluent was achieved, however drastically reduced along with total chemical oxygen demand (tCOD) removal at ADF>1.20% and indicated strong inhibition. Hence, the UASB reactor was fed at ADF = 1.05% [tCODinfluent = 8930 ± 2100 mg/L] and yielded >80% tCOD removal on average. Next generation sequencing (NGS) findings also revealed that Firmicutes and Bacteroidetes had the highest ratios of relative abundances in biomass sample taken at the last operating day; hence co-existence of these phyla played significant role in glycol removal with Synergistetes and Thermotogae bacteria whereas Methanobacterium and Methanoculleus archaea increased remarkably.

Despite the great profits of rubber latex production, its preliminary processing releases a large amount of wastewater into the water bodies from several processing steps. This rubber effluent is rich in total Kjeldahl nitrogen (TKN), total dissolved solids (TDS), biological oxygen demand (BOD) and chemical oxygen demand (COD). Therefore, the study addressed a liquid phase treatment of the effluent using an Upflow Anaerobic Sludge Blanket (UASB) reactor followed by coagu-flocculation and aeration. In addition, the gas phase (containing odorous hydrogen sulphide of 10–12% by volume) from the UASB reactor was sent to a caustic scrubber where the H2S removal efficiency of 63 ± 5% was achieved. This integrated multi-phase treatment scheme proved to be an effective approach by reducing TKN, TDS, BOD and COD by 68–87%, 61–69%, 81–84% and 81–87% respectively in the final effluent. [ABSTRACT FROM AUTHOR]

The aim of this study was to interpret the development of Anammox activity by a mathematical model in an UASB reactor -originally inoculated with methanogenic granules- at which Anammox progress has been also experimentally observed while treating chicken manure digestate. Since ammonium is derived from anaerobic degradation of nitrogenous compounds in chicken manure similar to any other nitrogen-rich organic wastes; the reactor was operated intentionally at favorable conditions [i.e.; with external nitrite source for NH4+:NO2-≅1.0] in order to make Anammox process to prevail as operation continued. Results indicated significant ammonia removals (60% on average) although influent concentration was gradually increased up to 200 mg L-1. A modeling exercise has been undertaken to investigate the performance of the laboratory scale UASB reactor. In this scope, the experimental results were modeled by using Mantis2 model within GPS-X 6.5 simulation software that included several built in libraries. Accordingly, effluent chemical oxygen demand (COD) and total ammonia nitrogen (TAN) concentrations could be predicted with reasonably good accuracy demonstrating successful calibration. The regression coefficient (R2) and mean relative absolute error (MRAE) parameters were found as 0.66 and 16% and 0.70 and 19%, respectively. [ABSTRACT FROM AUTHOR]

Life Cycle Assessment (LCA) was applied to estimate and analyze the environmental impacts from the construction and operation phases of a full-scale wastewater treatment plant (WWTP) located in the municipality of Lauro de Freitas, Bahia, Brazil. The WWTP process consists of the association of an Upflow Anaerobic Sludge Blanket (UASB) reactor followed by four constructed wetlands (CWL) and a disinfection step. The functional unit was defined as one cubic meter of treated effluent during the useful life of this WWTP (20 years). The LCA was carried out using SimaPro® software and the Centre of Environmental Science (CML) assessment method. The environmental impacts during construction phase were mainly from the wooden forms for concrete and the use of reinforcing steel. During the operation phase, the chlorine used as effluent disinfectant caused the greatest impacts in the abiotic depletion and acidification categories. Macronutrient concentrations present in the treated effluent and the methane generated also caused significant environmental impacts during the WWTP’s useful life. The results obtained highlight the importance of the application of a methodology like LCA to assist in decision-making with regard to the implementation, construction and operation of a WWTP.

A multistage system comprising an upflow anaerobic sludge blanket (UASB) followed by anoxic unit and then oxic activated sludge (AS) with biofilm is studied in El-Berka WWTP, Egypt. Different organic loading wastewaters of chemical oxygen demand (COD) less than 500 mg/L till 3000 mg/L are tested during the study. The hydraulic retention time (HRT) varies for each loading from 7.5 to 10 to 15 h. The UASB reactor accomplishes the removal efficiency of 50%–70% of influent COD. The overall system performs the removal efficiency of 95% of influent COD and NH4-N. Also, the results are verified by a modified mathematical model. [ABSTRACT FROM AUTHOR]

Anammox (anaerobic ammonium oxidation) is a promising technology to remove nitrogen from wastewater, but the long start-up time limits its practical application. This study used an up-flow anaerobic sludge bed (UASB) reactor, selected anaerobic granular sludge as inoculating sludge, and maintained pH (7.8-8.2), temperature (30-35°C), and DO (≤0.5 mg L-1) to start an anammox process. The initial start-up process occurred in three stages: cell lysis phase, activity lag phase, activity elevation phase. In the cell lysis (1-2 d) and activity lag (3-4 d) phases, denitrification was the main reaction and TN removal rates were 36.72% and 52.34%, respectively. In the activity elevation phase (5-30 d), denitrification weakened, anammox activity strengthened, NH4+-N removal rate was increased greatly, NO2 --N removal rate took on the trend of increasing at first and decreasing later, and the average removal rate of TN rose to 74.33% and reached the maximum rate of 81.91%. The variations of sludge bed in the cell lysis phase and activity lag phase were not obvious; but in the activity elevation phase, the sludge bed gradually varied from the bottom to the top, and the color of the sludge changed from black to brown, and a little sludge was red. [ABSTRACT FROM AUTHOR]

In this study, mature seeds of Zea mays (Malka 16) were irrigated with untreated and UASB-treated wastewater with combination of 50% textile and 50% sewage at hydraulic retention times (HRTs) of 0, 5, 10, and 15 h. Four other treatments diluted with distilled water (DW) were also evaluated. Eight-week analysis of irrigation revealed very small differences in the results of plant biomass and growth parameters of control and those irrigated with 15 h (HRT) treatments. The values of both types of water were observed as chlorophyll a and b contents, 5.9, 3.4, vs 5.5, 3.1 mg g−1, total chlorophyll 9.4 vs 8.8 mg g−1, carotenoids 9.5 vs 8.7 mg g−1, spad values 61.4 vs 56.3, net photosynthetic rate (A) 15.6 vs 14.5 μmol m−2 S−1, transpiration rate (E) 3.98 vs 3.8 μmol m−2 S−1, stomatal conductance 5.9 vs 5.8 μmol m−2 S−1, water use efficiency 10.3 vs 9.7 mmol Cmm−1 H2O, electrolyte leakage 115 vs 98% and total soluble proteins 385 vs 354 in leaves and 260 vs 231 g−1 FW in roots. While this stress enhanced H2O2 92 vs 115 and 195 vs 224 Units g−1, MDA 6.8 vs 9.1 and 5.9 vs 8.3 Units g−1, activities of enzymatic antioxidants SOD 25 vs 63 and 54 vs 63 Units g−1, POD 1170 vs 1310 and 570 vs 650 Units g−1, CAT 570 vs 820 and 880 vs 1040 Units g−1, and APX 235 vs 278 and 134 vs 187 Units g−1 in leaves and roots, respectively. Heavy metals (Cd, Cr, Cu, and Zn) in such plants were mostly within or about permissible limits of NEQS. The results obtained were more close to that of control. This practice may lead to clean environment and its reuse shall also reduce the stress on fresh water. Early researches transpire a little work done on the reuse of UASB-treated textile wastewater with co substrate, for irrigation purpose. [ABSTRACT FROM AUTHOR]

This study is focused on the effect of biogas recirculation with hydrogen sulfide removal on anaerobic treatment of sulfur-enriched synthetic wastewater in a UASB reactor. The presence of hydrogen sulfide in biogas causes problems in its further energy recovery while sulfides inhibit the anaerobic process. The reactor was gradually loaded with sulfates and their effect on the reactor operation was monitored. At the same time, external absorption of hydrogen sulfide from biogas with absorbent regeneration was operated. The results show that low concentrations of added sulfates support biogas production. At the sulfate concentration of 125 mg l−1, biogas production increased by approximately 2 l d−1. However, further increasing of the amount of sulfates in the substrate led to the opposite effect. At twice the amount of sulfates, the biogas production decrease by 1 l d−1 and its adverse effects on the removal of N-NH4, NC and P-PO4 were observed. Biogas recirculation through the absorption column ensured a decrease in the hydrogen sulfide concentration from 19 960 ppm to 4 030 ppm and an increase in the methane content from 59.2 % to 83 % and also a decrease in the sulfides concentration in the reactor. From the measured data it can be concluded that this method reduces sulfides inhibition. [ABSTRACT FROM AUTHOR]

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The objective of this research was to evaluate the distribution of the molecular weights of the recalcitrant organic matter contained in kraft mill effluents and identify microbial consortia responsible for an anaerobic biodegradable fraction. As a result, the average removal efficiencies of chemical organic demand (COD) and biological oxygen demand (BOD5) during the entire period of operation were 28% and 53%, respectively. The non-biodegradable organic matter was detected at molecular weights less than 1000 Da. However, most of the organic matter was in the molecular weight fraction higher than 10000 Da with 32 ± 11.6% COD as well as color (42.3 ± 8.7%), total phenolic compounds (35.9 ± 7.9%) and adsorbable organic compounds (AOX) (13.0 ± 2.7%). Methanogenic acetoclastic archaea of the genera Methanomethylovorans and Methanosarcina were found in the surface and middle zones of the reactor. Moreover, Methanosaeta and Methanolinea were identified in the low zone of the reactor. In all zones of the reactor, Desulfomicrobium and Desulfovibrio were found to be the most dominant genera of sulfate-reducing bacteria (SRB). [ABSTRACT FROM AUTHOR]

The anaerobic biological treatment of sulfate‐rich effluents, such as acid mine drainage (AMD), is mediated by sulfate‐reducing bacteria (SRB). This process involves the reduction of sulfates in the presence of an electron donor. Complex carbon compounds can be used as electron donors. In the present study, was used an upflow anaerobic sludge blanket (UASB) reactor to co‐treat a low‐pH synthetic AMD and cheese whey wastewater (CWW). Were observed higher sulfate and COD removal rates (1,114 ± 88 and 1,214 ± 128 mg L−1 day−1, respectively) at higher sulfate and applied COD loading rates (1,500 mg L−1 day−1). The overall pH of the effluent remained above 6.4 without any bicarbonate supplementation. Almost 100% of the Fe, Zn, and Cu was removed and the presence of metals improved the process. The use of a single reactor to treat AMD and CWW is promising. Practitioner points: Wastewater cheese whey was electron donor for treating acid mine drainage in an UASB reactor.Metals additions in the system indicated an increased removal of COD.About 99% of the metals were removed with the treatment. [ABSTRACT FROM AUTHOR]

There is a need for a broad study addressing different preservation conditions of anaerobic sludge and its activity after a prolonged storage. This study compared four different preservation methods of mesophilic anaerobic sludge for a period of up to 12 months: storage at 23 ± 2 °C, +4 °C, ‒20 °C, and freeze-dried. Anaerobic sludge was sampled from upper and bottom ports of an up flow anaerobic sludge blanket (UASB) reactor fed with microalgae and sodium acetate at organic loading rate of 5.4 gCOD/L·d. Specific methanogenic activity (SMA) tests were performed on the sludge samples after 2.5, 6, and 12 months of storage. Results demonstrated a statistically significant decrease in the SMA of the bottom port preserved sludge, but not of the upper port sludge, regardless of the method used for preservation. A varying susceptibility to the storage of the two types of the anaerobic sludge can be explained by the content of the methanogenic microorganisms, with bottom port sludge having a higher amount of the methane producing species. Interestingly, lyophilized samples were able to produce similar amounts of biogas when compared to the other three storage conditions, with the only difference of having a longer re-activation period. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: The aim of the present research was to provide a strategy for the start‐up of upflow anaerobic sludge blanket (UASB) reactors treating sugar cane vinasse, with emphasis on the relevant sulfur compounds along the reactor height. To this end, a laboratory‐scale UASB reactor was started up and its performance under the applied conditions was studied. RESULTS: Biomass was able to assimilate organic loading rates from 3 to 10 kg chemical oxygen demand (COD) mR−3 d−1, reducing VFAs accumulation, while increasing biogas production rate (BPR) from 0.92 to 4.12 m3 mR−3 d−1. The COD and sulfate (SO42−) were mainly removed in the reactor bed, showing homogenous distribution in the blanket and settler zones. However, from bottom to top of the reactor, a slight decrease of total and free sulfide concentrations was observed, indicating that the sludge bed in the UASB reactor was exposed to H2S concentrations higher than those measured in the reactor effluent. CONCLUSIONS: During 54 days, the development of macroscopic granules, the COD removal efficiency, the BPR and the CH4 content proved good indicators to monitor the start‐up period. Further research will be needed for strategy validation in pilot and full‐scale UASB reactors treating vinasse. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

An anaerobic (UASB) – hybrid aerobic (suspended and attached growth activated sludge) wastewater treatment system was evaluated on the removal of organic matter, solids and nitrogen following its pre-operational phase. Analysis were made weekly based on composite samples, prepared by grab samples taken every four hours, during 24-hour cycle, weighted by flow rate, on each monitoring point (raw sewage, UASB, anoxic chamber, aerobic reactors, return sludge from secondary decanters and final effluent). The plant presented an average flow rate of 908 m3/h with peaks from 10 to 14 h. BOD was removed by 86 % (310 to 41 mg/L) being the highest parcel accounted by UASB reactors (70 %) and removal of total suspended solids reached 63 % (190 to 94 mg/L). Mean removals of TKN (71 %) and Ammonium (77 %) were above the value predicted by design and, probably the nitrification-denitrification process was not the dominant route.

Organic liquid waste from food production industry is inevitable. High chemical oxygen demand (COD) contents in organic liquid waste could disrupt the water ecosystem. On the other hand, COD contents can be reduced and utilized to produce biogas by UASB reactor. However, there is a problem in operating UASB reactor, namely the high biomass content in methanogenic granule form, which is washed out with the effluent. The influent flow rate affects biomass content and the suitable flow rate is important for the particular UASB reactor. To investigate the matter, the estimation of Monod parameters is determined to study the kinetics of substrate (COD) and biomass (active methanogenic granule). In this work, simulations of lumped and distributed models are performed to observe the behavior of substrate and biomass inside the reactor. It is concluded that the suitable influent flow rate for UASB reactor is 150–175 m3/h, and the washed out biomass content is relatively low (from 0.001393 to 0.4919 kg/m3). The steady-state condition is achieved from 2027 to 2533 days, with high COD removal. [ABSTRACT FROM AUTHOR]