Range Of Organic Loading Rates Research Articles

Application of Recycled Filling to Improve the Purification Performance of Confectionery Wastewater in a Vertical Anaerobic Labyrinth Flow Bioreactor

Anaerobic wastewater treatment is, in many cases, a justified alternative to typical activated sludge processes, from a technological, economic, and ecological point of view. The optimisation of fermentation reactors is primarily concerned with increasing the biodegradation of organic compounds and biogas production, as well as improving efficiency in the removal of nitrogen and phosphorus compounds. The aim of the research was to determine the impact of using low-cost recycled filling on the efficiency of treating real confectionery wastewater in a vertical anaerobic labyrinth flow bioreactor. The experiments focused on selecting the organic loading rate that would allow for the effective biodegradation and removal of pollutants, as well as the efficient production of biomethane. It was found that the tested reactor can operate efficiently at a maximum organic loading rate (OLR) of 7.0–8.0 g of chemical oxygen demand (COD)/L·d. In this OLR range, high efficiency was guaranteed for both wastewater treatment and biogas production. However, increasing the OLR value to 8.0 g COD/L·d had a significant negative effect on the methane (CH4) content in the biogas. The most efficient variants achieved a biodegradation efficiency of around 90% of the organic compounds, a CH4 content of over 70% in the biogas, and a biogas yield of over 400 L/kg of COD removed. A significant influence of the applied OLR on the ratio of free organic acids (FOS) to total alkaline capacity (TAC) and pH was observed, as well as a strong correlation of these indicators with the specific biogas yield and CH4 content. The application of a solution based on the use of a hybrid system of anaerobic granulated sludge and an anaerobic filter resulted in an efficient treatment process and an almost complete elimination of suspensions from the wastewater.

Developing distillery biorefineries through dark fermentation of whiskey production by-products: the effect of organic loading rate on decarbonisation pathways

Biorefinery approaches can be utilised at distilleries using dark fermentation to treat whiskey production by-products and provide decarbonisation opportunities. A biorefinery can convert residues to hydrogen, carbon dioxide and volatile fatty acids (VFAs). This study investigated the effect of organic loading rate (OLR) on the production of VFAs and biogas in dark fermentation. Similar yields of hydrogen (5.6–6.9 ml H2. g-1 VS), carbon dioxide (18.3–24.9 ml CO2. g-1 VS), and VFAs (141.7–155.0 mg VFA. g-1 VS) were found for all OLRs. However, the composition of VFAs altered; higher caproic acid levels (1.2 g. L−1) were observed at low OLRs and higher valeric acid levels at high OLRs (2.0 g. L−1). The most prominent VFAs were butyric acid and acetic acid across the OLR range. The biogenic carbon dioxide and hydrogen offset potential was also assessed. A 50 million-litre whiskey distillery could satisfy approximately half of the carbon dioxide requirement of the Irish brewing industry. Biogenic hydrogen was found to be best suited as a transport fuel. The biorefinery supports the distillery’s transition to circular production systems.

Integration of mesophilic biogas plant in the animal slaughter process under real limitations: Techno-economic evaluation of a colombian bovine slaughterhouse.

Anaerobic digestion (AD) has been a widely tested alternative for the management and valorization of wastewater from the animal slaughter process. However, the integration of AD in slaughterhouses depends on technical and economic aspects. In Colombian slaughterhouses AD integration is limited by the availability of land. In the present study, a techno-economic evaluation of the AD of offal wastewater (OWW) stream in a laboratory scale mesophilic tubular digester was carried out. The digester was operated at organic loading rates (OLR) of 0.28, 0.50, 1.0, 1.5 and 2.0kg VS/m3 d. Boilers and a CHP (combined heat and power) system were considered for energy integration of biogas. For the economic study, the cost structure of a Colombian slaughterhouse was considered. The AD of OWW at 2.0kg VS/m3 d OLR was unstable with risk of inhibition. Increasing the OLR from 0.28 to 1.5kg VS/m3 d caused a reduction in the specific biogas production (SBP) from 0.474 to 0.069m3/kg VS However, the biogas production rate (BPR) remained constant at around 0.105m3/m3dig d for OLRs>0.28kg VSm3 d. Therefore, OWW anaerobic digestion in low-cost mesophilic biogas plants is technically feasible with OLRs between 0.28 and 1.5kg VS/m3 d. The implementation of boilers is economically favorable for OLR≥1.0kg VS/m3 d. Nevertheless, feasibility is very sensitive to variations in the cost structure. The implementation of CHP was feasible in the range of OLRs evaluated and its viability is not affected by changes in assumed costs.

Microbial electrochemical fluidized bed reactor (ME-FBR): An energy-efficient advanced solution for treating real brewery wastewater with different initial organic loading rates.

Electroactive bacteria are able to evolve strategies to transfer electrons with electroconductive materials. The boundaries of using electroactive bacteria to scale up wastewater treatments indicate the necessity to evaluate some of the most critical design and operational aspects. In this context, we have explored a concept so-called microbial electrochemical fluidized bed reactor (ME-FBR) for optimizing treatment of brewery wastewater by evaluating the anode potential, from + 200 mV to + 800 mV (vs. Ag/AgCl, 3 M reference electrode), in a vast range of Organic Loading Rate (OLR;0.23 kg COD/m3 d−1 to 23.60 kg COD/m3 d−1). Furthermore, the impact of the cathode nature (stainless steel mesh and sponge) and the electroconductive bed volume was evaluated regarding the wastewater treatment capacity. This manuscript reveals a positive impact on the ME-FBR capacity for treating wastewater: COD removal (87%) and nutrient removal (66% of TN and 75% of TP). Finally, the treatment energy consumption was always under 0.4 kWh Kg CODremoved−1 which was 10-fold lower than the required energy for aerating bioreactors from conventional activated sludge or membrane reactors.

Analysis of nitrous oxide emissions from aerobic granular sludge treating high saline municipal wastewater

Conventional activated sludge (CAS)-based wastewater treatment processes have the potential to emit high concentrations of nitrous oxide (N2O) during nitrification and denitrification, which can significantly impact the environmental performance and carbon footprint of wastewater treatment operations. While N2O emissions from CAS have been extensively studied, there is little knowledge of N2O emissions from aerobic granular sludge (AGS) which is now an increasingly popular secondary treatment alternative. The N2O emissions performance of AGS needs to be investigated to ensure that the positive benefits of AGS, such as increased capacity and stable nutrient removal, are not offset by higher emissions. This study quantified N2O emissions from a pilot-scale AGS reactor operated under a range of organic loading rates. A second CAS pilot plant was operated in parallel and under identical loading rates to allow for side-by-side comparison of N2O emissions from floc-based activated sludge. Under low loadings of <0.6 kg COD/m3/d the N2O emission factor from AGS and CAS were similar, at around 1.46 ± 0.1% g N2Oemitted/g ammonium loaded. A step increase in the organic loading rate increased N2O emissions from AGS more so than CAS which appeared to be attributed to the reactor feeding strategy that was required for AGS formation. The use of a separate anaerobic feeding phase which was followed by the aeration phase, resulted in extended periods of low dissolved oxygen (DO) concentrations combined with an initial high biomass ammonium loading rate, which favours N2O production and was exacerbated at higher organic loads. Conversely, the combined feeding plus aeration operation (aerobic feed) employed by the CAS system enabled a more even biomass ammonium loading rate and DO supply. This work has shown that while AGS has many operational benefits, the impacts that aeration profile, loading rate and feeding strategy have on N2O emissions must be considered.

Considering a membrane bioreactor for the treatment of vegetable oil refinery wastewaters at industrially relevant organic loading rates.

The present study aims to shed more light on the use of membrane bioreactors (MBRs) for the treatment of vegetable oil refinery wastewaters (VORWs). A MBR was operated for 157days in which it was fed with real VORW of varying composition at a range of organic loading rates (0.20 ± 0.05-3.79 ± 0.29 kg CODm-3day-1). The hitherto unconsidered fate of VORW constituents through the biological process was followed using gas chromatography/mass spectrometry analysis. This analysis revealed that only 19% of the identified feed constituents remained in the MBR effluent whereas ten new compounds were formed. Linear correlation analysis attributed the effluent residual COD to soluble microbial products (SMP) and non-readily biodegradable recalcitrant oily compounds. Trend of change of MLSS, mixed liquor viscosity and SMP with increasing OLR suggested that when MBR is operated under industrial conditions for the VORW treatment, the mixed liquor fouling propensity potentially increases with increasing OLR in the range studied.

The Potentials of an Integrated Ultrasonic Membrane Anaerobic System (IUMAS) in Treating Sugar Cane Wastewater

Excess levels of organic and inorganic matters in the discharge from sugarcane mill effluent (SCME) wastewater, causes the earnest environmental issue. In this study, a single unit integrated ultrasonic membrane anaerobic system (IUMAS) has been investigated for industrial sugarcane wastewater treatment. As the “Membrane-fouling” is one of the main constraints of IUMAS which eventually reduce the processing ability. In the present study, most researchers resort to cost reduction. IUMAS was alternatively applied as an economical approach for SCME wastewater treatment. The application of “Multiple-analysis” methods (COD, BOD, TSS) and three kinetic models during the treatment, suggested the specific range of organic loading rate to produce biogas. The result showed the increased methane gas production up to 80% in the biogas, with 94 -96% of COD removal efficiency from the SCME wastewater. Results concluded the effective efficiency of IUMAS to reduce the membrane fouling and treatment of SCME wastewater as well as enhanced production of methane gas.

Methane enhancement by the co-digestion of soybean straw and farm wastewater under different thermo-chemical pretreatments

This work aims to enhance and optimize the methane production by anaerobic co-digestion of soybean straw (SS) and farm wastewater. Thermo oxidation and alkali pretreatments were applied during the present study. The effects of chemical composition were investigated and the influence of thermo-chemical pretreatment on methane production by SS with wastewater was evaluated by Batch and semi-continuous experiments. All pretreatments were found significant (P < 0.05) to enhance the lignocellulosic degradability and methane yield. The highest methane yield which was recorded by 2% wet NaOH presoaking prior at 4.5% H2O2, 100 °C for 30 min pretreatment was 206 ml/g·VS which was 62% higher than the untreated straw during batch experiments. The synergistic effects were demonstrated during the anaerobic co-digestion of soybean straw and farm wastewater and the digestion period was shortened to almost half. In addition, a range of organic loading rate (OLR), (1.5–7.5) g·VS·L−1·d−1 was applied for the semi-continuous experiments and OLR of (3–6) g·VS·L−1·d−1 was concluded as the optimum OLR with the highest methane production capability of 194 ml/(g.VS.L.d).

Effect of organic loading rate on the recovery of nutrients and energy in a dual-chamber microbial fuel cell

This study aimed to assess the impacts of organic loading rate (OLR) (435–870 mgCOD/L·d) on nutrients recovery via a double-chamber microbial fuel cell (MFC) for treating domestic wastewater. Electricity generation was also explored at different OLRs, including power density and coulombic efficiency. Experimental results suggested the MFC could successfully treat municipal wastewater with over 90% of organics being removed at a wider range of OLR from 435 to 725 mgCOD/L·d. Besides, the maximum power density achieved in the MFC was 253.84 mW/m2 at the OLR of 435 mgCOD/L·d. Higher OLR may disrupt the recovery of PO43−-P and NH4+-N via the MFC. The same pattern was observed for the coulombic efficiency of the MFC and its highest value was 25.01% at the OLR of 435 mgCOD/L·d. It can be concluded that nutrients and electrical power can be simultaneously recovered from municipal wastewater via the dual-chamber MFC.

STUDI PENURUNAN KANDUNGAN BOD55, COD, TSS, DAN WARNA PADA AIR LIMBAH INDUSTRI PENCELUPAN KAIN MENGGUNAKAN METODE LAHAN BASAH BUATAN (CONSTRUCTED WETLAND)

ABSTRACT&#x0D; Dyeing industries as part of textile processess produce wastewater which affect water bodies and harmfull for living organism in water caused by moderate organic compounds and high color. This study use free floating macrophytes constructed wetland methods with water hyacinth plant (Eichornia crassipes) to determine level of removal efficiency of BOD5, COD, TSS, and color intensity of wastewater from one of dyeing industry in Denpasar. Experiment was carried out in a laboratory scale to study the influence of plant on the treatment efficiency of waste water. This study was descriptive quantitative with BOD5, COD, TSS, and color intensity testing from dyeing wastewater. The result of the experiment shows the removal efficiency of BOD5 is 11,06% - 53,09%, COD is 8,31% - 55,22%, TSS is 6,84%, - 59,47%, and color intensity is 7,54% - 34,8% and the pH range is 7,33 – 8,90. Organic loading rate range is 424,57kg/ha.d - 2233,88 kg/ha.d. It summarized that constructed wetland using water hyacinth has low BOD5, COD, TSS, and color removal efficiency due to some effluent sample are higher than quality standard of Kep.Men.51/Men.LH/10/1995. Furthermore, the batch reactor test with no prior treatment result showed water hyacinth has low efficieny to remove color from dyeing waste water.&#x0D; Keywords: removal efficiency, dyeing wastewater, constructed wetland, water hyacinth

Performance of an ECSB reactor for high-rate anaerobic treatment of cheese industry wastewater: effect of pre-acidification on process efficiency and calcium precipitation.

An external circulation sludge bed (ECSB) reactor was studied at full-scale (1,000 m3) during anaerobic treatment of cheese and other dairy products industry wastewater (CWW). The latter was characterized by a high calcium content, therefore the study focused on the potential negative impact that calcium may have in the long-term. The degree of CWW acidification (25 and 40%) on ECSB reactor performance was evaluated over a wide range of organic loading rates from 5 up to 18 kg m3 d-1, while process efficiency and calcium precipitation were examined in detail. Independently of the operating conditions, the volatile suspended solids content of the anaerobic granular sludge, as well as its calcium content, remained stable along the ECSB reactor operation, indicating that there was no calcium build up in the biomass. The results of this study demonstrate that the ECSB design seems to be particularly suitable to treat calcium-rich wastewater that is probably due to the fact that in this system CaCO3 precipitates in the bulk liquid of the external circulation tank and not the biomass present in the main reactor, and that the CaCO3 crystals are washed-out from it due to the high upflow velocity applied to the system (5 m h-1).

Anaerobic digestion of thin stillage of corn ethanol plant in a novel anaerobic baffled reactor

In this study, the performance of a conventional anaerobic baffled reactor (ABR) and a novel configuration of hybrid ABR for the treatment of thin stillage was evaluated. The hybrid ABR achieved the chemical oxygen demand (COD) removal, sulfate removal and methane yield of 97–94%, 94–97% and 294–310 mL CH4 g−1 CODremoved, respectively at organic loading rate (OLR) of 1–3.5 kg COD m−3 d−1. On the other hand, the value of COD and sulfate removal and methane yield for the conventional ABR were 75–94%, 67–76% and 140–240 mL CH4 g−1 CODremoved, respectively at OLR range of 1.1–1.8 kg COD m−3 d−1. The enhanced performance and robustness of the novel ABR was demonstrated to be the result of incorporation of solid/liquid/gas separators into the configuration of the conventional ABR, leading to reduced biomass washout, higher solid retention time and significantly improved phase separation.

Digestion Performance and Microbial Metabolic Mechanism in Thermophilic and Mesophilic Anaerobic Digesters Exposed to Elevated Loadings of Organic Fraction of Municipal Solid Waste

Mesophilic and thermophilic anaerobic digestion reactors (MR and TR) for the organic fraction of municipal solid waste (OFMSW) were tested to reveal the differential microbial responses to increasing organic loading rate (OLR). MR exhibited faster adaptation and better performance at an OLR range of 1.0–2.5 g VS·L−1·d−1, with average profiles of a biogas yield of 0.38 L/gVSadded*d at 0.5 g/L*d OLR and 0.69 L/gVSadded*d at 2.5 g/L*d OLR, whereas TR had a biogas yield of 0.07 L/gVSadded*d at 0.5 g/L*d OLR and 0.44 L/gVSadded*d at 2.5 g/L*d OLR. The pyrosequencing results of amplicons revealed the microbial mechanisms of OFMSW anaerobic digestion. Larger shifts in the bacteria composition were observed in the TR with OLR elevation. For methanogens in both reactors, Methanothrix dominated in the MR while Methanosarcina was favored in the TR. Moreover, analysis of the mode and efficiency of metabolism between the MR and TR demonstrated different performances with more efficiency related to the limiting hydrolytic acid step.

Bioelectrochemically assisted anaerobic digestion system for biogas upgrading and enhanced methane production

The objective of this study was to evaluate the effect of biofilm and external voltage on the performance and microbial community composition of batch-fed, combined anaerobic digestion-bioelectrochemical cell (AD-BEC) systems under different operational conditions. A dextrin/peptone mixture was fed at a range of organic loading rates (0.34 to 1.37g COD/L-d). The hybrid system with both suspended biomass and biofilm without any external potential application achieved a substantially higher initial soluble COD consumption (53.7±2.3% vs. 39.7±3.7) and methane (CH4) production (331 vs. 225mL) within one day of feeding than the conventional AD system (suspended biomass only). Compared to the conventional AD system, the hybrid systems had higher resilience to shock organic loadings. A range of external potential (0.5 to 2.0V vs. Ag/AgCl) was applied to AD-BEC reactors, developed with two different start-up procedures. A potential of 2.0V resulted in water electrolysis leading to a higher CH4 production rate (105 vs. 84mL/L-d) and biogas CH4 content (88.5±1.4 vs. 64.5±1.9%) in the AD-BEC reactor (closed vs. open circuit condition, respectively). Application of external potential enriched putative exoelectrogens at the anode biofilm and hydrogenotrophic methanogens at the cathode biofilm, which may have contributed to the observed enhanced CH4 production in the AD-BEC system. A phylotype related to Methanobacterium formicicum, a hydrogenotrophic methanogen, dominated the archaeal community in the AD-BEC cathode biofilm.

Optimization of fermentative hydrogen production from palm oil mill effluent in an up-flow anaerobic sludge blanket fixed film bioreactor

Response surface methodology with a central composite design was applied to optimize fermentative hydrogen production from palm oil mill effluent (POME) in an upflow anaerobic sludge blanket fixed film reactor. In this study, the concurrent effects of up-flow velocity (Vup) and feed flow rate (QF) as independent operating variables on biological hydrogen production were investigated. A broad range of organic loading rate between 10 and 60 g COD L−1 d−1 was used as the operating variables. The dependent parameters as multiple responses were evaluated. Experimental results showed the highest value of yield at 0.31 L H2 g−1 COD was obtained at Vup and QF of 0.5 m h−1 and 1.7 L d−1, respectively. The optimum conditions for the fermentative hydrogen production using pre-settled POME were QF = 2.0–3.7 L d−1 and Vup = 1.5–2.3 m h−1. The experimental results agreed very well with the model prediction.

Impact of aluminum chloride on process performance and microbial community structure of granular sludge in an upflow anaerobic sludge blanket reactor for natural rubber processing wastewater treatment

In this study, granular sludge formation was carried out using an aluminum chloride supplement in an upflow anaerobic sludge blanket (UASB) reactor treating natural rubber processing wastewater. Results show that during the first 75 days after the start-up of the UASB reactor with an organic loading rate (OLR) of 2.65 kg-COD·m(-3)·day(-1), it performed stably with a removal of 90% of the total chemical oxygen demand (COD) and sludge still remained in small dispersed flocs. However, after aluminum chloride was added at a concentration of 300 mg·L(-1) and the OLR range was increased up to 5.32 kg-COD·m(-3)·day(-1), the total COD removal efficiency rose to 96.5 ± 2.6%, with a methane recovery rate of 84.9 ± 13.4%, and the flocs began to form granules. Massively parallel 16S rRNA gene sequencing of the sludge retained in the UASB reactor showed that total sequence reads of Methanosaeta sp. and Methanosarcina sp., reported to be the key organisms for granulation, increased after 311 days of operation. This indicates that the microbial community structure of the retained sludge in the UASB reactor at the end of the experiment gave a good account of itself in not only COD removal, but also granule formation.

Rapid formation and pollutant removal ability of aerobic granules in a sequencing batch airlift reactor at low temperature

ABSTRACTThe start-up of an aerobic granular sludge (AGS) reactor at low temperature was more difficult than at ambient temperature.The rapid formation and characteristics of AGS in a sequencing batch airlift reactor at low temperature were investigated. The nutrient removal ability of the system was also evaluated. It was found that compact granules with clear boundary were formed within 10 days and steady state was achieved within 25 days. The settling properties of sludge were improved with the increasing secretion of extracellular polymeric substances and removal performances of pollutants were enhanced along with granulation. The average removal efficiencies of COD, NH4+–N, total nitrogen (TN), total phosphorus (TP) after aerobic granules maturing were over 90.9%, 94.7%, 75.4%, 80.2%, respectively. The rise of temperature had little impact on pollutant biodegradation while the variation of dissolved oxygen caused obvious changes in TN and TP removal rates. COD concentrations of effluents were below 30 mg l−1 in most cycles of operation with a wide range of organic loading rates (0.6–3.0 kg COD m−3 d−1). The rapid granulation and good performance of pollutant reduction by the system might provide an alternate for wastewater treatment in cold regions.

Investigation of anaerobic biodegradability of real compost leachate emphasis on biogas harvesting

Anaerobic treatability of real compost leachate was assessed using laboratory-scale anaerobic sequencing batch reactor at mesophilic conditions. Interventional study was conducted at wide range of organic loading rate 0.93–25 g l−1 day−1 by varying hydraulic retention times 23 and 12 h. Initial chemical oxygen demand (COD) was 1.85–25 g l−1. pH variations; total, soluble (SCOD), readily biodegradable (rbCOD) chemical oxygen demand; volatile fatty acids degradation; biogas production; and methane fraction were considered in this study. The organic matter removal efficiencies were in the range of 76–81 % depending on loading rates applied. The maximum volumetric methane production rate of 5.7 l CH4 l−1 day−1 was achieved at the loading rate of 19.65 g l−1 day−1. About 85 % of removed organic matters during the biodegradation were converted to the methane. The results have shown that the anaerobic batch reactor could be an appealing option for changing compost leachate into the useable products such as biogas and other energy-rich compounds, which may play a serious role in meeting the world’s ever-increasing energy requirements in the future.

Effect of organic loading rate on anaerobic digestion: Case study on recycled paper mill effluent using Modified Anaerobic Hybrid Baffled (MAHB) reactor

Organic Loading Rate (OLR) effect on the performance of Modified Anaerobic Hybrid Baffled (MAHB) bioreactor treating recycled paper mill effluent (RPME) was investigated in this present study. The MAHB reactor is operated with a range of OLR of 0.14–4.00 gm COD/lit/day by varying the influent Chemical Oxygen Demand (COD) concentration of 1000, 2000, 3000 and 4000 mg/lit and Hydraulic Retention Time (HRT) of 1, 3, 5 and 7 days. From the experiment, it was found that the reactor performance decrease when OLRs increase. Highest specific methane yield is 8.47 lit CH4/day with OLR of 1.33 gm COD/lit/day. The highest methane content achieved is 91.63 % from total of 6.43 lit biogas/day at a range pH of 6.6–7.5. Effluent Volatile Fatty Acid (VFA) was below 35 mg/lit HOAC throughout the experiment while alkalinity where fluctuated at low OLR and slightly stable as the OLR increases. Higher OLRs of 2.0 to 3.0 gm COD/lit/day results in addition of inorganics in the reactor causing destabilization of the reactor and process failure, and thereby significantly affect the reactor performance in terms of organic removal. The OLR of 1.33 gm COD/lit/day was found to be optimum for MAHB reactor for the effective treatment of RPME both in terms of specific methane yield and COD removals.

Feasibility of large amounts biogas production from garbage bioliquid

Aims: One of the best available alternatives to face the energy and environment problem is to tend renewable energies. The main aim of this study is producing biogas from garbage bioliquid (leachate). Materials and Methods: This study was conducted at wide range of organic loading rate (OLR = 0.93-25 g COD l -1 d -1 ) by varying hydraulic retention times (HRT = 23 and 12 hsr) and initial COD of 1.85-25 g l -1 . pH variations, COD, SCOD, rbCOD and VFAs degradation, biogas and methane production were considered in this study. Results: The COD removal efficiencies were in the range of 76-81% depending on loading rates applied. The maximum volumetric methane production rate (VMPR) of 5.7 l CH4 l -1 d -1 was achieved at the OLR of 19.65 g COD l -1 d -1 . About 85% of removed COD during the biodegradation was converted to methane. Conclusion: The results have shown that the anaerobic sequencing batch reactor (ASBR) reactor could be an appealing option for changing composting leachate into useable products such as biogas and other energy-rich compounds, which may play a serious role in meeting the world's ever-increasing energy requirements in the future.