Up-flow Anaerobic Sludge Fixed Film Research Articles

Effect of temperature and hydraulic retention time on hydrogen production from palm oil mill effluent (POME) in an integrated up-flow anaerobic sludge fixed-film (UASFF) bioreactor

The current state of palm oil mill wastewater treatment focuses solely on open ponding or closed lagoon systems for biogas production. However, efforts to convert this wastewater into biohydrogen are limited. Therefore, this research investigates the feasibility of converting palm oil mill effluent (POME) for biohydrogen production via dark fermentation. Temperature and hydraulic retention time (HRT) effects on biohydrogen production and COD removal efficiency in an up-flow anaerobic sludge fixed-film (UASFF) bioreactor were investigated. The experiment was carried out and analysed using a central composite design (CCD) and the Response Surface Methodology (RSM). The hydrogen (H 2 ) yield, H 2 production rate (HPR), and COD removal efficiency were investigated as responses. HPR increased significantly by 28.8 folds as temperature increased from 37 °C to 53.5 °C (transition from mesophilic to thermophilic) at HRT of 3 h. Meanwhile, the COD removal efficiency significantly increased from 24.76% to 33.33% between 4 to 9 h of HRT. Maximum H 2 yield of 0.95 L H 2 g −1 COD removed , HPR of 10.39 L H 2 d −1 , and 35.9% COD removal were reported at the optimum HRT and temperature of 7 h and 57 °C, respectively. This study indicates that under the thermophilic condition and short HRT, POME could be treated while producing biohydrogen using the UASFF bioreactor. • The temperature has a significant impact on hydrogen yield and hydrogen production rate. • Low HRT significantly impacted the COD removal efficiency of POME. • Optimum temperature and HRT were 57 °C and 7 h, respectively. • Acetobacter spp. is found to be dominant under a thermophilic condition in the H 2 -UASFF unit.

A review of upflow anaerobic sludge fixed film (UASFF) reactor for treatment of dairy wastewater

Abstract Dairy trade is one in all the foremost vital agro-based industries in Bharat, that uses huge quantities of water for process of milk and alternative functions and releases large amount of effluent a day. Summarizing case studies and recent analysis efforts in upflow anaerobic sludge mounted film reactor for treating dairy wastewater is the objective of this paper. Farm is one in all the key industries inflicting pollution. In recent years because of the rise within the population, a high demand for the additional economical use of water resources and it reprocess has hugely modified in each urban & rural area. Considering the multiplied milk demand, the farm trade in Bharat is predicted to grow chop-chop and have the waste generation and connected environmental issues are assumed multiplied importance. The up flow anaerobic sludge mounted film reactor is commonly found to be an efficient methodology of treatment for the treatment of farm waste material. For the treatment of farm waste material effluents, initial attention is targeted on bench, pilot-scale up flow anaerobic sludge mounted film reactor. Since the most characteristics of the farm waste material are known, the first constituent in dairy waste waters, particularly carbohydrates, proteins and lipids has been delineated in the degradation mechanism. The present paper may be a review on the many strategies and their performance analysis comparison of farm waste material on the premise of evaluated parameters. Main objective of this study is to seek out simpler manner of treatment victimization comparison.

Effect of HRT on biogas yield in treating dairy industry wastewater using Upflow Anaerobic Sludge Fixed Film reactor

Abstract Nowadays dairy and milk-based merchandise has become most essential and vital role in day-after-day lifetime of human. The milk undergoes varied process in dairy farm industries to supply different dairy products. More water and different chemicals are needed during a dairy unit. The amount of water employed in a dairy trade depends upon the supply of water, process technique and sort of flow. The wastewater after every step of process is discharged into either the natural water bodies or to the surroundings that alters the ecological balance. This study illustrates the impact of hormone replacement therapy on performance of work Upflow Anaerobic Sludge Fixed Film (UASFF) reactor on treatment of dairy industry. The UASFF reactor was designed for an efficient volume of 0.013 m3 with Fujino Spirals as packing media at the highest of reactor and operated underneath mesophilic condition. when startup amount, the reactor was operated with HRTs of 30, 24, 18, 12 and 6hr for the common inflowing COD concentrations of 8500 mg/L, 10000 mg/L, 11500 mg/L, 13000 mg/L and 14500 mg/L severally. The results showed that the utmost biogas yield efficiencies were within the vary of 0.162–0.505 m3/kg COD at inflowing concentration of 8500 mg/L and 14500 mg/L severally.

Biodegradation performance of UASFF reactor in treating Dairy wastewater under various organic Loading rate

An up flow anaerobic sludge-fixed film (UASFF) reactor could be a granular sludge bioreactor that was used for the fast-biological conversion of organic concern biogas with the aids of aggregative microbic association. The major downside related to the traditional UASB reactor is that the long period for start- up amount, during this study, UASFF bioreactor with granular flow behaviour was developed to shorten the start-up amount at low Hydraulic Retention Time. The huge quantities of water and totally different chemicals area unit required throughout a dairy plant. The degree of water used in an exceedingly dairy trade varies with connection the provision of water, methodology and sort of flow. The wastewater once every step of method is discharged into either the natural water bodies or to the setting that alters the ecological balance. This analysis work on the laboratory scale model is utilized for the analysis and treatment of farm trade effluent. This study evaluates the influence of Organic Loading Rate in the biodegradation performance of a lab scale hybrid up flow anaerobic sludge fixed film (UASFF) reactor for treating synthetic dairy industry wastewater. The lab scale UASFF reactor was designed and fabricated for an effective volume of 13L with Fujino spiral as packing media at the top of reactor and operated in continuous mode. The reactor was operated for different Organic Loading Rate ranging from 0.28 kg COD/m 3 . d to 2.33 kg COD/m 3 . d by varying the influent COD concentrations of 8500 mg/L,10000 mg/L, 11500 mg/L, 13000 mg/L and 14500 mg/L under steady state condition.

Effects of temperature and dark fermentation effluent on biomethane production in a two-stage up-flow anaerobic sludge fixed-film (UASFF) bioreactor

In a two-stage of up-flow anaerobic sludge fixed-film (UASFF) bioreactor, palm oil mill effluent (POME) wastewater was used as inoculum and substrate to study the biodegradation in association with hydrogen and methane production. During the first stage (H2-UASFF unit), different temperatures (37–70 °C) and hydraulic retention time (HRT) was designed and analyzed using response surface methodology (RSM) for biohydrogen production. In the second stage (CH4-UASFF unit), at 24 h HRT, a continuous experiment was carried out using the same temperature and effluent from H2-UASFF unit (also known as dark fermentation effluent) was used as substrate (12–20 g COD L−1). This study is focusing on the second stage of UASFF bioreactor (i.e. CH4-UASFF) for biomethane production. Studied parameters were designed using Historical Data in RSM. Its effects on methane production rate (MPR), methane yield, biogas percentage and COD removal were analyzed. The relation between initial effluent COD and temperature on biomethane production and overall reactor performance treating POME wastewater were also examined. Results showed that 76% of total COD removal efficiency (TCOD) was achieved using two-stage UASFF bioreactor. The MPR of 15.63 L CH4 d−1, methane yield of 0.803 L CH4 g−1 CODrem.d−1, COD removal efficiency of 66.28% and 93.31% of CH4 at optimum temperature and effluent COD of 54 °C and 12 g COD L−1, respectively were obtained in CH4-UASFF unit. Based on this study, thermophilic temperature and low POME concentration showed a significant impact on biomethane production and more than 70% of TCOD of POME was reduced at 24 h HRT.

Sludge Blanket Height (SBH) as a Process Stability Indicator in UASFF Reactor: Relationship Between SBH and Sludge Concentration at Different Operating Conditions

Sludge blanket height (SBH) is considered as one of the most significant parameters in design of up flow anaerobic sludge blanket (UASB) bioreactor. The SBH adjusts appropriate sludge concentration inside the bioreactor which subsequently hinders washout phenomenon. In addition, maximum organic loading that the bioreactor can undergo is determined on the basis of this parameter. This study investigates the effects of two independent operating variables, organic loading rate (OLR) and up-flow velocity (Vup), on the SBH and also sludge concentration at different ports (S1-S4) of an up-flow anaerobic sludge fixed film (UASFF) bioreactor treating palm oil mill effluent (POME). A central composite face-centered design (CCFD) was employed to design the experiments and nine different conditions at three levels of each variable were determined (3.8, 16.4 and 29.0 g COD/l.d of OLR and 0.2, 1.6 and 3.0 m/h of Vup). The variations of sludge concentration (at S4) and gas production rate (q) as a function of the variables were analyzed and modeled using response surface methodology (RSM). From the results, simultaneous increase in both variables led to a decrease in the sludge concentration from 2.3 to 1.6 g/l, whereas, the variables showed an increasing trend in the q from 0.09 to 0.37 m3/m2. h. Furthermore, the sludge concentration and the SBH were also modeled using Narnoli and Mehrotra’s equation in Sigma Plot Software. The experimental results were well fitted with the model predictions. The changes of the SBH and sludge concentration under different operating conditions were ranged from approximately 0.1–0.7 m and 0–65 g/l, respectively. The experimental and modeling findings also manifested the direct impact of the Vup on the SBH.

UASFF start-up for biohydrogen and biomethane production from treatment of Palm Oil Mill Effluent

A start-up study was conducted to produce biohydrogen and biomethane from Palm Oil Mill Effluent (POME) using a two-stage up-flow anaerobic sludge fixed-film (UASFF) bioreactor. 100% molasses was used to start the system, and POME was added at 10% increments until it reached 100% after 59 days. During this period of continuous operation, the HRT and temperature were adjusted in order to optimize the condition for biogas production. Hydrogen and methane gas production fluctuated between 53–70% and 90–95%, respectively, in the last four days of operation (days 56–59), with POME percentage being increased from 70% to 100% (30%–0% molasses). Using 100% raw POME led to a total COD removal of 83.70%, average gas production rates of 5.29 L H2 d−1 (57.11% H2) and 9.60 L CH4 d−1 (94.08% CH4), in their respective units. This output is comparable to, if not better than using 100% molasses as substrate. This work concludes that based on the relative consistency of biogas production on days 56–59, the two-stage UASFF bioreactor operating at a final HRT of 4 h and temperature of 43 °C has taken a period of two months for start-up.

Effect of Temperature on the Performance of an Up-flow Anaerobic Sludge Fixed Film (UASFF) Bioreactor Treating Palm Oil Mill Effluent (POME)

This study investigates the performance of anaerobic digestion of palm oil mill effluent (POME) in an up-flow anaerobic sludge fixed film (UASFF) bioreactor at four different temperatures (24, 38, 50 and 60 °C) under optimized operating conditions (feed flow rate (QF) of 1.5 L day and up-flow velocity (Vup) of 0.75 m/h). Influent COD concentration was 14150 mg/L. Six quality parameters viz. COD removal, methane yield, TSS removal, oil and grease removal, effluent volatile fatty acids (VFA) and pH were monitored as the process response. COD removal and methane yield of 92% and 0.325 CH4/g CODremoved day were achieved respectively in mesophilic temperature (38 °C) at HRT of 1.5 day. Higher values (94% COD removal and 0.331 CH4/g CODremoved day) were obtained under thermophilic condition (50 °C). A 94% oil and grease removal was achieved at a temperature of 50 °C while it was 85 and 65% at 38 and 24 °C, respectively. The granules structure and activity did not undergo any changes at temperature of 50 °C. An increase in temperature from 50 to 60 °C caused a detrimental effect on treatment efficiency as the methanogenic activity was relatively terminated within <6 days.

Investigation on up-flow anaerobic sludge fixed film (UASFF) reactor for treating low-strength bilge water of Caspian Sea ships.

BackgroundIn order to meet the International Maritime Organization (IMO) objectives, the main purpose of this study was using the cheap and practical wastewater treatment system for low-strength bilge water of Caspian Sea ships; therefore, the low-strength bilge water of the Caspian Sea ships has been treated by up-flow anaerobic sludge fixed film (UASFF) reactor at the ambient temperature.ResultsThe reactor operated at two hydraulic retention times (HRTs) of 10 h and 8 h. The organic loading rates (OLR) ranged (0.12-0.6) g chemical oxygen demand (COD)/l.day. At the beginning of the experimental procedure, the sludge was immobilized on the surface of the support materials. After 10 days of batch feeding of the reactor with the wastewater as an acclimation period (with COD removal of 59%), the reactor operated continuously. At the end of the experiment, with the HRT of 8 h and OLR of 0.6 g COD/l.day, the COD and total suspended solid (TSS) removal efficiencies reached the amounts of 75% and 99%, respectively. In addition to the good features of the reactor in removing COD and TSS, the effluent oil concentration was significantly lower than the standard value (15 ppm) which has been laid down for the discharge of the bilge water from ships by the IMO.ConclusionsThe obtained data demonstrated that UASFF reactor is an appropriate system for treatment of a low-strength bilge water.

Performance of up flow anaerobic sludge fixed film bioreactor for the treatment of high organic load and biogas production of cheese whey wastewater

Among various wastewater treatment technologies, biological wastewater treatment appears to be the most promising method. A pilot scale of hybrid anaerobic bioreactor was fabricated and used for the whey wastewater treatment. The top and bottom of the hybrid bioreactor known as up flow anaerobic sludge fixed film (UASFF); was a combination of up flow anaerobic sludge blanket (UASB) and up flow anaerobic fixed film reactor (UAFF), respectively. The effects of operating parameters such as temperature and hydraulic retention time (HRT) on chemical oxygen demand (COD) removal and biogas production in the hybrid bioreactor were investigated. Treatability of the samples at various HRTs of 12, 24, 36 and 48 hours was evaluated in the fabricated bioreactor. The desired conditions for COD removal such as HRT of 48 hours and operation temperature of 40 ?C were obtained. The maximum COD removal and biogas production were 80% and 2.40 (L/d), respectively. Kinetic models of Riccati, Monod and Verhalst were also evaluated for the living microorganisms in the treatment process. Among the above models, Riccati model was the best growth model fitted with the experimental data with R2 of about 0.99.

Response surface analysis of effects of hydraulic retention time and influent feed concentration on performance of an UASFF bioreactor

The interactive effects of hydraulic retention time (HRT) and influent chemical oxygen demand (COD in) on the performance of an up-flow anaerobic sludge fixed film (UASFF) bioreactor treating palm oil mill effluent (POME) was studied. Anaerobic digestion of POME was modeled and analyzed with two variables i.e. HRT and COD in. Experiments were conducted based on a general factorial design and analyzed using response surface methodology (RSM). The region of exploration for digestion of POME was taken as the area enclosed by HRT (1–6 days) and COD in (5260–34,725 mg/l) boundaries. Eight dependent parameters were either directly measured or calculated as response. Increase in the variables resulted in decrease in COD removal efficiency, solid retention time (SRT) and sludge retention factor (SRF) and increase of COD removal rate, volatile fatty acid to alkalinity ratio (VFA/Alk), CO 2 percentage in biogas and methane production rate. The value of the maximum specific microbial growth rate ( μ m) determined through the equation that correlated organic loading rate (OLR) and μ (calculated by quadratic model for SRF) was found to be 0.153 d −1. This value was close to that obtained using Chen and Hashimoto kinetic equation (0.207 d −1) in a previous study. The present study provides valuable information about interrelations of quality and process parameters in POME digestion using a UASFF bioreactor.

Biological treatment of whey in an UASFF bioreactor followed a three-stage RBC

Biological treatment of a high strength chesses whey wastewater was investigated in a series of aerobic-anaerobic experiments. Aerobic treatment of the wastewater was conducted in a three-stage rotating biological contactor (NRBC), while the anaerobic process was performed in an up-flow anaerobic sludge fixed film (UASFF) bioreactor. Various concentrations of wastewater with influent COD of 40,000 to 70,000 mg/L were introduced in to NRBC system. Treatability of the samples at various HRTs of 8, 12 and 16 h was evaluated in the NRBC reactor. The effluent streams of the NRBC system were introduced into UASFF bioreactor. Anaerobic treatment of the pretreated samples was investigated in an UASFF with the same HRTs of 8, 12 and 16 h. The obtained results revealed that more than 53, 69 and 78% of the influent COD (50,000 mg/L) were removed in NRBC reactor at HRTs of 8, 12 and 16 h, respectively. Maximum COD removal efficiencies of 96, 96.8, 97.4 and 96.4% were achieved in the combined systems at total HRT of 32 h for influent COD of 40,000, 50,000, 60,000 and 70,000 mg/L, respectively.

Optimization of pre-treated palm oil mill effluent digestion in an up-flow anaerobic sludge fixed film bioreactor: A comparative study

An up-flow anaerobic sludge fixed film (UASFF) bioreactor was used to treat physically and chemically pre-treated palm oil mill effluent (POME) under different operating conditions. In physical pre-treatment, POME was pre-settled for 2 h and the supernatant was fed to the reactor. In chemical pre-treatment, optimum dosages of a cationic and an anionic polymer were used. Experiments of pre-treated POME digestion were conducted based on a central composite face-centered design (CCFD) with two independent operating variables, feed flow rate ( Q F) and up-flow velocity ( V up). The operating variables were varied to cover a wide range of organic loading rates (OLR) from 3.8 to 29 g COD/(l d). Six dependent parameters were either directly measured or calculated as response. These parameters were total COD (TCOD) removal, effluent pH, effluent total volatile fatty acid (TVFA), effluent bicarbonate alkalinity (BA), methane yield ( Y M), and solids retention time (SRT). The performance of the reactor was compared for the pre-settled and chemically pre-treated POME. The chemical pre-treatment approach was shown to be more predictable, reliable and practical as the sludge produced was very compressible and was easy to separate. At a comparable range of Q F and V up, the pre-settled POME yielded slightly better reactor performance in terms of COD removal (%), bicarbonate alkalinity and methane yield. At an OLR of about 16.5 g COD/(l d), higher COD removal efficiency (90–94%) was achieved compared to that of the chemically pre-treated POME (82–88%) despite about 33% of organics in the pre-settled POME was contributed by suspended solids. The optimum conditions for digestion of the pre-settled and chemically pre-treated POME were determined as Q F of 1.65 l/d, V up of 0.6 and Q F of 2.45 l/d, V up of 0.75, respectively. The experimental findings were in close agreement with the model prediction.

Process modeling and analysis of palm oil mill effluent treatment in an up-flow anaerobic sludge fixed film bioreactor using response surface methodology (RSM)

In this study, the interactive effects of feed flow rate ( Q F) and up-flow velocity ( V up) on the performance of an up-flow anaerobic sludge fixed film (UASFF) reactor treating palm oil mill effluent (POME) were investigated. Long-term performance of the UASFF reactor was first examined with raw POME at a hydraulic loading rate (HRT) of 3 d and an influent COD concentration of 44 300 mg/l. Extreme reactor instability was observed after 25 d. Raw POME was then chemically pretreated and used as feed. Anaerobic digestion of pretreated POME was modeled and analyzed with two operating variables, i.e. feed flow rate and up-flow velocity. Experiments were conducted based on a central composite face-centered design (CCFD) and analyzed using response surface methodology (RSM). The region of exploration for digestion of the pretreated POME was taken as the area enclosed by the feed flow rate (1.01, 7.63 l/d) and up-flow velocity (0.2, 3 m/h) boundaries. Twelve dependent parameters were either directly measured or calculated as response. These parameters were total COD (TCOD) removal, soluble COD (SCOD) removal, effluent pH, effluent total volatile fatty acid (TVFA), effluent bicarbonate alkalinity (BA), effluent total suspended solids (TSS), CH 4 percentage in biogas, methane yield ( Y M), specific methanogenic activity (SMA), food-to-sludge ratio (F/M), sludge height in the UASB portion and solid retention time (SRT). The optimum conditions for POME treatment were found to be 2.45 l/d and 0.75 m/h for Q F and V up, respectively (corresponding to HRT of 1.5 d and recycle ratio of 23.4:1). The present study provides valuable information about interrelations of quality and process parameters at different values of the operating variables.

EFFECTS OF ORGANIC LOADING RATE ON PALM OIL MILL EFFLUENT TREATMENT IN AN UP-FLOW ANAEROBIC SLUDGE FIXED FILM BIOREACTOR

The effect of OLR provided by hydraulic retention time (HRT) and influent chemical oxygen demand (CODin) on the performance of an up-flow anaerobic sludge fixed film (UASFF) bioreactor treating palm oil mill effluent (POME) was studied. Anaerobic digestion of POME was modeled and analyzed with two variables i.e. HRT and CODin. Experiments were conducted based on a general factorial design and analyzed using response surface methodology (RSM). The region of exploration for digestion of POME was taken as the area enclosed by HRT (1 to 6 days) and CODin (5260 to 34725 mg/L) boundaries. Eight dependent parameters were either directly measured or calculated as response. These parameters were total COD (TCOD) removal, TCOD removal rate, volatile fatty acids to alkalinity ratio (VFA/Alk.), CO2 fraction in biogas, solid retention time (SRT), sludge retention factor (SRF), methane production rate per volume of the reactor and feed. A simultaneous increase of the variables determined a decrease of COD removal efficiency, SRT and SRF and an increase of COD removal rate, VFA/Alk., CO2 fraction in biogas, methane production rate. The present study provides valuable information about interrelations of quality and process parameters at different values of the operating variables.

Kinetic evaluation of palm oil mill effluent digestion in a high rate up-flow anaerobic sludge fixed film bioreactor

A kinetic study of the anaerobic digestion process of palm oil mill effluent (POME) was carried out in a laboratory-scale up-flow anaerobic sludge fixed film (UASFF) bioreactor at mesophilic temperature (38 °C). Influent COD concentrations in the range of 5260–34725 mg/l were applied at steady state conditions. Chen and Hashimoto kinetic equation and a simplified Monod's model was employed to describe kinetics of POME anaerobic digestion at organic loading rates in the range of 0.88–34.73 g COD/l day. The hydraulic retention times (HRT) ranged between 1 and 6 days. Throughout the experiment, the removal efficiency of COD was between 80.6 and 98.6%. The methane production rate was between 0.287 and 0.348 l CH 4/g COD removed day. Biokinetic coefficients; apparent half-velocity constant, A, half-velocity constant, K s, maximum specific microbial growth rate, μ m, methane yield constant, Y M, and growth yield constant, Y x, were evaluated. The apparent rate constants, K, calculated by simplified Monod model were in the range of 2.9–7.4 l CH 4/g COD day. At different influent COD concentrations, K values showed a linear relationship with variations of VSS content of the reactor.

High-rate anaerobic digestion of palm oil mill effluent in an upflow anaerobic sludge-fixed film bioreactor

The upflow anaerobic sludge-fixed film (UASFF) reactor is one of the granular sludge bioreactors that are used for the rapid biotransformation of organic matter to methane with the help of granulated microbial aggregates. The UASFF reactor is a hybrid reactor with an upflow fixed film (UFF) part over an upflow anaerobic sludge blanket (UASB) section. The major problem associated with UASB reactors is the long start-up period (2–4 months). In this study, a UASFF bioreactor with tubular flow behavior was developed in order to shorten the start-up period at low hydraulic retention time (HRT) for palm oil mill effluent (POME) treatment. The reactor was operated at 38 °C and HRT of 1.5 and 3 days. The organic loading was gradually increased from 2.63 to 23.15 g chemical oxygen demand (COD)/l day. Granular sludge was rapidly developed within 20 days. The size of granules increased from an initial pinpoint size to reach 2 mm. High chemical oxygen demand removals of 89 and 97% at HRT of 1.5 and 3 days were achieved, respectively. Methane yield of 0.346 l CH 4/g COD removed at the highest organic loading rate (OLR) was obtained. The use of an internal upflow anaerobic fixed film section caused the flocculated biomass to precipitate over the sludge blanket. The precipitated biomass served as suitable and natural hydrophobic core to form a spatial arrangement of microbial species in the process of mature bio-granulation.