Anaerobic Hybrid Reactor Research Articles

RANCANGAN TAPAK PENGOLAHAN LIMBAH CAIR PABRIK MINYAK KAYU PUTIH (Melaleuca cajuputi subsp. Cajuputi Powell) DENGAN REAKTOR HIBRID ANAEROB (Kasus Pabrik Minyak Kayu Putih Gelaran, Gunung Kidul)

This research is aimed to study the contamination level of Gelaran Cajuput Oil Plant wastewater, to obtain the design of the treatment site plan, and to recommend the determination of the site plan location. The phases covered pilot field survey to determine the location, measuring the volume and collecting the sample, analizing the process and deciding the treatment system. The results showed the contamination level parameters were acid pH, and high BOD and COD. The appropriate length, width, and depth of chamber units’ dimension and specifications of the treatment yielded were respectively as follows: a) 1.5 m, 1.0 m, and 1.0 m of equalisation; b) 1.5 m, 1.0 m, and 1.0 m of neutralization; c) 1.25 m, 1.06 m, and 1.25 m of anaerobic hybrid reactor; d) 1.5 m, 1.0 m, and 1.0 m of stabilization, and was located on downward to facilitate the effluent flowing by gravitational force merely. Key Words : Cajuput oil, waste water treatment, site plan, anaerobic hybrid reactor

2-biofuels (H2 and CH4) production from anaerobic digestion of biscuits wastewater: Experimental study and techno-economic analysis

The up-flow anaerobic hybrid reactor (UAHR) was simultaneously employed for 2-biofuels (H2 and CH4) production from solely biscuits wastewater (BW) industry and a mixture of BW with domestic sewage (DS) at a mixing ratio of 3:1 respectively. The UAHR was fed with BW and operated at an organic loading rate (OLR) of 21.9 ± 1.7 gCOD/L/d., and hydraulic retention time (HRT) of 12.0 h. The module achieved volumetric hydrogen production rate (VHPR) and hydrogen yield (HY) of 0.95 ± 0.13 L/L reactor/d., and 118.6 ± 22.3 mL/gCODremoved respectively. A substantial deterioration in the H2 productivity was occurred after 94 days of continuous-feed operation, due to the inhibition effect of long-chain fatty acids (LCFAs). DS was integrated into the BW at mixing ratio of 3.0 (BW):1.0 (DS) where the UAHR was continuously operated at OLRs of 7.95 and 4.45 gCOD/L/d., achieving H2 and CH4 yields of 414.2 ± 38.1 and 318.5 ± 23.5 mL/gCOD removed, respectively. The payback periods for the production of biogas rich CH4 and H2 were 7.1 and 5.7 y respectively.

Anaerobic treatment of slaughterhouse wastewater: a review.

This article presents a review of anaerobic treatment technologies to treat slaughterhouse wastewater including its advantages and disadvantages. Physico-chemical characteristics and biochemical methane potential (BMP) of slaughterhouse wastewater are addressed. Various anaerobic treatment technologies are presented with the related operating parameters, viz., hydraulic retention time (HRT), organic loading rate (OLR), upflow velocity (Vup), and biogas yield vis-a-vis treatment efficiency in terms of chemical oxygen demand (COD). In addition, various factors that affect the anaerobic treatment of slaughterhouse wastewater such as high oil & grease (O & G) concentration in influent, inhibitors, volatile fatty acids (VFAs), and the loading rate are also addressed. The literature review indicated that the slaughterhouse wastewater can be treated effectively by employing any anaerobic treatment technologies at OLRs up to 5 kg COD/m3.d with more than 80% COD removal efficiency without experiencing operational problems. Anaerobic hybrid reactors (AHRs) were found the most effective among various reviewed technologies because of their ability to operate at higher OLRs (8 to 20 kg COD/m3.d) and lower HRTs (8 to 12 hrs).

Performance of Anaerobic Hybrid Reactor with Post-Treatment in Intermittent Flow Sand Filter: a Sulfide-Oxidizing Bioprocess for the Treatment of Sanitary Sewage Using Nitrate as Electron Acceptor

The aim of the study was to evaluate the oxidation of sulfides using nitrate as an electron acceptor in an anaerobic hybrid reactor (AHR) connected to an intermittent flow sand filter (IFSF) for post-treatment. The study was carried out in four phases in which the AHR was fed with 100% raw sewage (phase I) followed by phases II, III and IV involving different proportions of raw sewage and recycled nitrified IFSF effluent (83:17, 67:33 and 50:50, respectively). The results showed that 41% of the oxidized forms of sulfur were accumulated in the anaerobic phase with 31% in the form of sulfate and 10% as elemental sulfur. Increased proportions of nitrified IFSF effluent into the AHR favored denitrification and afforded up to 38% removal of nitrogen during the anaerobic stage and 46% in the final effluent. The removal efficiency of total dissolved sulfide by the system was up to 99.3% in phase IV, the influent of which contained the highest proportion of nitrified effluent. It is concluded that the combination of AHR and IFSF offers excellent conditions for the removal of chemical oxygen demand, nitrogen and sulfides from sanitary sewage using nitrate as an electron acceptor. Furthermore, the proposed treatment system represents a low-cost and energy-saving approach that addresses the anaerobic digestion of biosolids as well as the control of malodorous gas formation.

Kinetic Analysis and Treatment of Compost Leachate Using Data from a Plant-Scale Hybrid Anaerobic Reactor

AbstractCompost leachate is one of the most strongly polluting wastewaters, which is found in significantly large amounts. The major objective of this research was to study the biological treatment...

A hybrid anaerobic and microalgal membrane reactor for energy and microalgal biomass production from wastewater

In the concept of a circular economy, wastewater is no longer waste but a resource for water, energy and nutrients. In this study, a hybrid system containing an anaerobic membrane bioreactor (AnMBR) and a microalgal membrane reactor (MMR) was developed to harvest energy, nutrients, and microalgal biomass from food and agribusiness industrial wastewater. The AnMBR removed over 97% of chemical oxygen demand (COD) and generated 4.7 ± 0.15 L (n=80) of biogas equivalent to 2.4 kWh kg−1 COD (feed) d−1. Through anaerobic metabolism, the microorganism in AnMBR generated NH4+ and PO43− -rich effluent. Their effluent concentrations were 1.9 and 1.4 times of that in the influent, respectively. NH4+ and PO43−-rich effluent was directly used (i.e. without filtration or sterilization) to culture microalgae Chlorella vulgaris in the MMR. . Microalgal biomass production reached up to 700 mg/L after 6 days of operation and nutrient removal rates of above 75% were achieved. However, biomass production and nutrient removal declined towards the end of experiment. The generated biomass was completely harvested using cationic polyacrylamide at the dose of 36 mg g−1 dry weight. Overall, the AnMBR has great potential to produce energy. Future research is needed to intensify the microalgal growth (e.g. genetic modification of strains, addition of plant hormones) in the MMR for continuous operation of the hybrid system.

Prediction of biogas production rate from anaerobic hybrid reactor by artificial neural network and nonlinear regressions models

In the present study, a three-layer artificial neural network (ANN) and nonlinear regression models were developed to predict the performance of biogas production from the anaerobic hybrid reactor (AHR). Firstly, the performance of an AHR which is filled with perlite (2.38–4.36 mm) at fill rates of 1/3, 1/4 and 1/5 for the treatment of synthetic wastewater was investigated at a loading rate of 5, 7.5, 10, 12.5 and 15 kg COD m−3 day with 12, 24, 36 and 48 h of hydraulic retention time (HRT) under mesophilic conditions (37 ± 1 °C). In this study, experimental data were used to estimate the biogas production rate with models produced using both ANNs and nonlinear regression methods. Moreover, ten related variables, such as reactor fill ratio, influent pH, effluent pH, influent alkalinity, effluent alkalinity, organic loading rate, effluent chemical oxygen demand, effluent total suspended solids, effluent suspended solids and effluent volatile suspended solids, were selected as inputs of the model. Finally, ANN and nonlinear regression models describing the biogas production rate were developed. The R2, IA, FA2, RMSE, MB for ANNs and nonlinear regression models were found to be 0.9852 and 0.9878, 0.9956 and 0.9945, 0.9973 and 0.9254, 217.4 and 332, 36 and 222, respectively. The statistical quality of ANNs and nonlinear regression models were found to be significant due to its high correlation between experimental and simulated biogas values. The ANN model generally showed greater potential in determining the relationship between input data and the biogas production rate according to statistical parameters (except R2 and R). The results showed that the proposed ANNs and nonlinear regression models performed well in predicting the biogas production rate of AHR on behalf of avoiding economic and environmental sustainability problems.

Evaluation of bioenergy potential from citrus effluents through anaerobic digestion

At the global level, citrus production is around 92 million tons and citrus processing is about 22 million tons generating 28 million m3 of Citrus Effluents. In the last two decades, the generation of wastewater by the citrus industry has increased, and since earlier studies have focused mostly on solid citrus waste, there is inadequate information related to the potential energy value of these effluents. The main contribution of this work is the development of a methodology for conducting an energy analysis to determine the amount of electrical energy that can be derived from the biogas produced in the anaerobic digestion of citrus effluents at the global level. This determination was made through the operation of a novel, high-rate reactor, called the Anaerobic Hybrid Reactor. The aim of this paper was to evaluate the bioenergy potential of the effluents from the citrus industry by using anaerobic digestion to generate electrical energy. As part of the results of this evaluation, it was found that one ton of processed oranges generates 1.25 m3 of citrus effluents, 0.72 m3 of methane at standard temperature and pressure, 7.16 kWh of gross electricity, and 2.15 kWh of net electricity, which represents a cost of 0.17 USD. The worldwide bioenergy potential from citrus effluents by the main citrus processing countries is approximately 16 million m3 of methane/year at standard temperature and pressure, which is equivalent to approximately 159 GWh of gross electricity per year, about 48 GWh of net electricity per year, and about 111 GWh of thermal energy per year. The biogas that is produced can replace as much as 9% of the consumption of fuel oil and natural gas used in a citrus processing plant. Anaerobic digestion is a clean, simple energy technology, and it helps to minimize the social, environmental, and economic problems caused by poor management and the lack of alternatives for the treatment of the effluents from the citrus industry.

Mixed dye wastewater treatment in a bioelectrochemical system-centered process

The feasibility of mixed dye wastewater treatment was evaluated with a novel integrated bioprocess that consisted of a hybrid anaerobic reactor (HAR) with a built-in bioelectrochemical system, an aerobic biofilm reactor (ABFR) and a denitrification reactor (DR). The position of the DR significantly affected chemical oxygen demand (COD) and colority in effluent, and placing the DR after the ABFR improved effluent quality probably due to minimization of the undesired autoxidation of aromatic amine in dye wastewater. The optimal integrated process of HAR + ABFR + DR efficiently treated mixed dye wastewater, and concentrations of COD and TN were decreased down to 75 ± 18 mg/L and 12.91 ± 0.31 mg/L, respectively, along with colority 48 ± 4 times. Total phosphorus reduced to below 0.5 mg/L with coagulation using poly aluminum chloride, and the effluent quality fully met the discharge standard. This comprehensive study suggests the feasibility of the BES based process for practical application to mixed dye wastewater treatment.

Hydrodynamics of up-flow hybrid anaerobic digestion reactors with built-in bioelectrochemical system

Understanding the electrode configuration is vital for the successful application of bioelectrochemical system (BES) in recalcitrant wastewater treatment. Especially in those traditional anaerobic processes that integrate with BES to construct effective hybrid bioreactors. Hybrid bioreactors employed granular graphite as electrode material achieved 86.62 ± 1.83% decolorization efficiency of azo dye acid orange 7 (AO7) at influent AO7 loading rate of 800 g/(m3∙d) and it was about 6% higher than that with carbon fiber brush electrodes. Such electrodes were positioned above the anaerobic sludge layer and higher efficiency (8%) than the reactors with electrodes placed beneath the sludge layer was observed. Tracer experiments and modeling of residence time distribution indicated that the fluid pattern in hybrid bioreactors was modified to plug flow pattern and had a better consummate mixing ability compared to the conventional anaerobic reactor. Simulation using computational fluid dynamics technique showcased favorable mass transfer near electrode modules. The hydrodynamics of simulation and experimental results were connected by simplifying electrode module as a porous media model. This study thus proved that hybrid bioreactors can effectively enhance wastewater treatment comprehensively through the analysis of decolorization performance and hydrodynamics.

Efficient azo dye wastewater treatment in a hybrid anaerobic reactor with a built-in integrated bioelectrochemical system and an aerobic biofilm reactor: Evaluation of the combined forms and reflux ratio

A combined process that consisted of a hybrid anaerobic reactor (HAR) with an integral bioelectrochemical system and aerobic biofilm reactor (ABFR) was established for simulated azo dye wastewater treatment (domestic wastewater containing dye acid orange 7). The split combination form that separated HAR and ABFR into two individual reactors recorded a decolorization efficiency of 81.23 ± 0.12%, which was about 8% higher than that HAR and ABFR were stacked together into a single up-flow reactor. Implementation of reflux improved the decolorization and chemical oxygen demand (COD) removal in both the processes. Decolorization efficiency achieved 97.52 ± 0.66% in split process at a reflux ratio of 1 and the COD was 89 ± 2 mg/L in the final effluent. Further increasing the reflux ratio to 3 did not have any significance in treatment performance of the reactors. This study comprehensively revealed the influence of combination forms and reflux ratio on the performance of combined process.

Influence of heavy metal Cr (VI) containing effluents on anaerobic microbiome in a novel hybrid anaerobic reactor: Linking with reactor performance for enhanced treatment

The study investigated anaerobic treatment of high strength effluents polluted with Cr (VI), in hybrid anaerobic reactor (HAR) developed at IIT Delhi. Performance was evaluated by a time-course analysis, conducted for two different phases i.e. granulation and treatment, linked with the microbiome dynamics. During granulation higher methane was generated while, it was substantially hindered during the second phase. Genera with degradation abilities were identified viz- Methanobacterium, Clostridium, Halorhodospira, Oscillibacter, Pseudomonas, Stenotrophomonas, Methylobacterium. Bioaugmentation with such keystone species will help maintain microbially active centers. The findings indicated extreme bacterial reduction (R = −0.986, CI = 0), coupled with hindered acidogenesis. Methanomicrobiales prevailed in the treating phase while, aceticlastic families flourished during granulation. Further, non-metric multidimensional scaling, principal component analysis explored the interactions between environmental, microbial and chemical variables. With the focus on the applicability of anaerobic treatment with tannery-type of effluents, the study provided a comprehensive investigation for superior monitoring.

Effects of external recirculation on a two-stage mainstream anaerobic-anammox treatment system.

Nitritation-anammox treatment can be a potentially energy- and resource-efficient technology for treating mainstream wastewater. However, the issue of nitrate residue from anammox treatment remains to be addressed. Herein, external recirculation of the anammox effluent to a hybrid anaerobic reactor (HAR), which was also to provide a continuous flow with low COD/N for the nitritation-anammox reactor, was employed to decrease the residue compounds. The recirculation ratio of 50% was observed to be the optimal to achieve the best overall performance with potential savings in energy demand. Specifically, in the operation scenario of R=50%, the highest COD removal of ~90% by the HAR was achieved. Meanwhile, the lowest COD/NH4 + -N ratio of ~2.0 in the HAR effluent ensured the lowest observed NO3 - -N/NH4 + -N ratio of ~14% in the nitritation-anammox reactor. These results have demonstrated the feasibility of applying external recirculation for nitrate residue removal via denitrification in the anaerobic pretreatment stage. PRACTITIONER POINTS: Nitritation-anammox treatment is an attractive method for mainstream wastewater treatment. Nitrate residue from anammox processes contributes to total nitrogen in the final effluent. Recirculation of anammox effluent to an anaerobic reactor can decrease nitrate residue. A recirculation ratio of 50% results in a low COD/NH4 + ratio of 2 that benefits the subsequent anammox.

Application of hybrid anaerobic reactor: Treatment of increasing cyanide containing effluents and microbial composition identification

The study endeavors the anaerobic treatment of cyanide-containing effluents using the hybrid anaerobic reactor, with self-immobilized granules under high up-flow velocities. Comparison of one-year time-course analyses of HARs treating high strength effluents containing cyanide and control indicates the importance of wastewater characteristics in development and maintenance of microbiome. Efforts were directed towards associating process performance with microbial dynamics. Presence of cyanide results in the accumulation of intermediates paralleled with a drop in abundance of sensitive aceticlastic methanogens. HAR appear to have better resilience than other identified digesters because of shielding effects and enhanced granule-wastewater contact. The predominance of Methanobacteriales in the presence of cyanide can be linked to its tolerance. It was found that methane yield is positively correlated with abundance of aceticlastic guilds (R = 0.830, CI = 0.01). Tolerant bacterial groups were also identified. The study advances our knowledge related to less energy intensive technology with the focus on the development of efficient HAR.

Development of denitrifying phosphate accumulating and anammox micro-organisms in anaerobic hybrid reactor for removal of nutrients from low strength domestic sewage

Low strength domestic sewage was treated in an Anaerobic Hybrid Reactor. The first phase was focused on the enhancement of denitrifying phosphate accumulating organisms (DPAOs) for the concurrent removal of nitrogen and phosphate. 16S rRNA gene confirmed the presence of Flavobacterium spp. and Pseudomonasalcaligenes spp. which are dominant DPAOs. The second phase was the anaerobic ammonium oxidation (anammox) enrichment phase, and it exhibited much higher chemical oxygen demand (87%) and nitrogen removal (90%) as compared to the first phase. However, it had failed to remove the phosphate from the system. In case of anammox, the dominant specie detected was Candidatus Brocadia, along with minor counts of Candidatus Jettenia and Anammoxoglobus Propionicus. Apart from that, ammonia oxidizing bacteria (Nitrosomonas europaea, Nitrosomonas nitrosa) and methanogens (Methanosaeta, Methanobacterium) were also detected in the system. This study showed the feasibility of anammox species over DPAOs in treating domestic sewage.

SIMULATED DAIRY WASTEWATER TREATMENT IN A PILOT PLANT SCALE MAGNETO-ACTIVE HYBRID ANAEROBIC BIOFILM REACTOR (MA-HABR)

The aim of this study was to determine the effects of magneto-active microporous packing media manufactured by extrusion technology and modified by the addition of relevant amounts of metal catalysts and magnetic activation on the effectiveness of simulated dairy wastewater (SDW) treatment and biogas productivity in a pilot plant scale hybrid anaerobic biofilm reactor with full mixing. The best performance was found at an organic loading rate (OLR) in the range 6.0 - 8.0 kg COD/m3·d, where the chemical oxygen demand (COD) removal was about 80%, the biogas yield ranged from 256.7 - 310.9 L/kg CODremoved, the methane production ranged from 420.6 - 557.1 L/d and total phosphorus removal ranged from 82.9 - 90.7%. The study demonstrated that the application of the innovative packing media in the biofilm-bed reactor enhanced the sorption of organic matter, biogas productivity and the binding of biogenic compounds.

Evaluating the effects on performance and biomass of hybrid anaerobic reactor while treating effluents having glucose with increasing concentrations of 4-chlorophenols

Anaerobic treatment of industrial effluents is limited by higher sensitivity of anaerobes. High rate digesters resulted in achievement of higher loadings at lower retention times but, efficiencies were limited due to sensitivity. In this study, performance of novel hybrid anaerobic reactor (HAR) was investigated using high strength effluents combined with increasing 4-chlorophenol loadings. HAR is capable of handling much higher OLRs than UASB system, due to completely fluidized state and AFBR because of greater microbial maintenance. The reactor employs self-immobilized granules for biomass retention. Its temporal analysis demonstrated the effects on glucose removal, 4-chlorophenol removal, biogas generation and intermediates accumulation. These variables were related to microbial dynamics as revealed by profiling of reactor population which strongly correlated to increasing 4-chlorophenol levels. Methanogenesis was hindered with substantial decline in COD removal attributed to intermediates built-up (R > 0.7, CI = 0). This was paralleled with diminished archaeal abundance (R = 0.902, CI = 0), especially aceticlastic groups. HAR achieved 73% and 57.5% 4-chlorophenol and COD removal efficiencies, respectively at 200 ppm 4-chlorophenol loadings. Many genera were identified as tolerant possessing biodegradation capability viz: Methanobacterium, Clostridium, Pseudomonas, Rhodococcus, Bellilinea etc. C. cavendishii, P. knackmussii, R. phenolicus, B. caldifistulae were identified on the fingerprint with increasing pollutant levels. Aerobes having versatile metabolisms were acknowledged in strict anaerobic conditions with involvement in toxin removal. The study demonstrated higher resilience of HAR in comparison to other high rate digesters (like UASB, AFBR) due to its unique characteristics. The findings will help in technological advancement of HAR to grope the effects of 4-chlorophenol while treating high strength effluents.

Microalgae-mediated bioremediation and valorization of cattle wastewater previously digested in a hybrid anaerobic reactor using a photobioreactor: Comparison between batch and continuous operation

Scenedesmus obliquus (ACOI 204/07) microalgae were cultivated in cattle wastewater in vertical alveolar flat panel photobioreactors, operated in batch and continuous mode, after previous digestion in a hybrid anaerobic reactor. In batch operation, removal efficiencies ranges of 65 to 70% of COD, 98 to 99% of NH4+ and 69 to 77.5% of PO4−3 after 12days were recorded. The corresponding figures for continuous flow were from 57 to 61% of COD, 94 to 96% of NH4+ and 65 to 70% of PO4−3 with mean hidraulic retention time of 12days. Higher rates of CO2 fixation (327–547mgL−1d−1) and higher biomass volumetric productivity (213–358mgL−1d−1) were obtained in batch mode. This microalgae-mediated process can be considered promising for bioremediation and valorization of effluents produced by cattle breeding yielding a protein-rich microalgal biomass that could be eventually used as cattle feed.

Anaerobic degradation of glycol ether-ethanol mixtures using EGSB and hybrid reactors: Performance comparison and ether cleavage pathway

The anaerobic biodegradation of ethanol-glycol ether mixtures as 1-ethoxy-2-propanol (E2P) and 1-methoxy-2-propanol (M2P), widely used in printing facilities, was investigated by means of two laboratory-scale anaerobic bioreactors at 25oC: an expanded granular sludge bed (EGSB) reactor and an anaerobic hybrid reactor (AHR), which incorporated a packed bed to improve biomass retention. Despite AHR showed almost half of solid leakages compared to EGSB, both reactors obtained practically the same performance for the operating conditions studied with global removal efficiencies (REs) higher than 92% for organic loading rates (OLRs) as high as 54 kg of chemical oxygen demand (COD) m−3 d−1 (REs of 70% and 100% for OLRs of 10.6 and 8.3 kg COD m−3 d−1 for E2P and M2P, respectively). Identified byproducts allowed clarifying the anaerobic degradation pathways of these glycol ethers. Thus, this study shows that anaerobic scrubber can be a feasible treatment for printing emissions.

Correction to: Anaerobic digestion of citrus industry effluents using an Anaerobic Hybrid Reactor

In the original publication of the article, the corresponding author name was published incorrectly as A. Lassman-Alvarado. This has been updated in this correction article. The original article has also been corrected.