Treatment Of Molasses Wastewater Research Articles

Post-treatment of anaerobically pre-treated molasses wastewater in an aerobic granular sludge sequencing batch reactor

An aerobic granular sludge system was used for post-treatment of an Up-Flow Anaerobic Sludge Blanket (UASB) reactor treating molasses wastewater. The system was very effective in the treatment of the UASB reactor effluent. Up to 94.9-96.0% COD removals could be observed and it showed no signs of serious stress when subjected to high COD loads of 7.9 g l−1d−1. The total nitrogen removals were in excess of 80.2% with the maximum ammonia-N loads up to 0.6 g l−1d−1. For Suspended Solids (SS), the removal efficiencies ranged between −320.4% and 84.8% in different operating periods. The aerobic granules with excellent settleability promoted high solid retention and low solid washout in the reactor.

Treatment of molasses wastewater in a membrane bioreactor: Influence of membrane pore size

Due to high chemical oxygen demand (COD) and its low biodegradability, molasses wastewater is usually classified as a high-strength industrial wastewater. The possibility and efficiency of a membrane bioreactor (MBR), containing lab-made membrane modules, in treating molasses containing wastewater was studied. The research was conducted in two phases, namely a first period of fed-batch operation followed by a second with continuous MBR operation. The results showed that more than 80, 90 and 30%, respectively, of the COD, total nitrogen (TN) and color were removed. There was a clear influence of the membrane pore size on trans-membrane pressure (TMP) build-up. Scanning electron microscopy and Fourier transformed infrared (FT-IR) analyses revealed no significant differences in organic constituents between the membrane cake layer and the activated sludge.

Electricity generation from molasses wastewater by an anaerobic baffled stacking microbial fuel cell

AbstractBACKGROUND: The conventional treatment of molasses wastewater has many disadvantages including intensive energy requirements, excessive chemicals consumption and large quantities of waste generation. The microbial fuel cell (MFC) is a promising technology for power generation along with wastewater treatment. However, low power output and high construction costs limit the scale‐up and field implementation of MFCs. In this study, a novel anaerobic baffled stacking microbial fuel cell (ABSMFC) composed of four units was constructed and used to treat molasses wastewater.RESULTS: The ABSMFC was operated at three different organic loading rates (OLRs) and the highest average power density of 115.5 ± 2.7 mW m−2 was achieved for the four units at an OLR of 3.20 kg COD m−3 d−1. Accordingly, 50–70% of total COD removal efficiency was accomplished. Power generation was further improved in terms of voltage or current by connecting units in series or parallel. The low voltage loss (8.1%) during series connection resulted from low parasitic current of adjacent units.CONCLUSION: The ABSMFC is effective for molasses wastewater treatment. It can promote current or voltage output and minimize energy loss during series connection. This is a promising scalable architecture and can be combined with other existing wastewater treatment technologies. Copyright © 2010 Society of Chemical Industry

The Operation Characteristics of Biohydrogen Production in Continuous Stirred Tank Reactor with Molasses

The feasibility and operation characteristics of anaerobic fermentation biohydrogen production in a continuous stirred tank reactor (CSTR) were investigated for treating molasses wastewater. The research indicates that the reactor has the capacity of continuously producing hydrogen in an initial biomass (as volatile suspension solids) of 17.74 g/L, temperature of (35±1) °C, hydraulic retention time (HRT) of 6 h, and the reactor can start up the ethanol-type fermentation in 12 days and realize stable hydrogen production. Furthermore, the CSTR reactor enjoys a favorable stability even with an organic shock loading. When the organic loading rate (OLR) increased from 8 kg/(m3•d) to 24 kg/(m3•d), the CSTR system reached a new steady state within 9 d. The hydrogen yield and COD removal increased from 3 L and 8% to 12 L and 20% respectively with the hydrogen content of 47 %.

A fuzzy-logic-based model to predict biogas and methane production rates in a pilot-scale mesophilic UASB reactor treating molasses wastewater

A MIMO (multiple inputs and multiple outputs) fuzzy-logic-based model was developed to predict biogas and methane production rates in a pilot-scale 90-L mesophilic up-flow anaerobic sludge blanket (UASB) reactor treating molasses wastewater. Five input variables such as volumetric organic loading rate (OLR), volumetric total chemical oxygen demand (TCOD) removal rate ( R V), influent alkalinity, influent pH and effluent pH were fuzzified by the use of an artificial intelligence-based approach. Trapezoidal membership functions with eight levels were conducted for the fuzzy subsets, and a Mamdani-type fuzzy inference system was used to implement a total of 134 rules in the IF-THEN format. The product (prod) and the centre of gravity (COG, centroid) methods were employed as the inference operator and defuzzification methods, respectively. Fuzzy-logic predicted results were compared with the outputs of two exponential non-linear regression models derived in this study. The UASB reactor showed a remarkable performance on the treatment of molasses wastewater, with an average TCOD removal efficiency of 93 (±3)% and an average volumetric TCOD removal rate of 6.87 (±3.93) kg TCOD removed/m 3-day, respectively. Findings of this study clearly indicated that, compared to non-linear regression models, the proposed MIMO fuzzy-logic-based model produced smaller deviations and exhibited a superior predictive performance on forecasting of both biogas and methane production rates with satisfactory determination coefficients over 0.98.

Hollow fiber membrane fouling and cleaning in a membrane bioreactor for molasses wastewater treatment

The limitation of membrane microfi ltration for activated sludge wastewater treatment is membrane fouling which is indicated by the decline of the permeation flux. In this study, molasses were used to prepare a synthetic feed substrate with addition of urea (NH2) 2CO and sodium pyrophosphate Na4PO4 to adjust the COD:N:P ratio. A polyethersulfone hollow fiber membrane was operated under the typical range of concentrations of mixed liquor suspended solids of an activated sludge process. The membrane bioreactors (MBR) system was operated in two modes, first with increasing flux and then at constant flux. In this study, the amount of extracted extracellular polymeric substance (eEPS) was lower than in earlier reports, whereas the soluble microbial product (SMP) was quite similar. Carbohydrates were the main part for both eEPS and SMP, reflecting the composition of molasses. Since membrane fouling occurred, several maintenance and recovery cleaning procedures were tested: NaOCl, NaOCl + Memcare, and citric aci...

Polishing Treatment of Molasses Wastewater with Iron Salts: the Role of Counter‐ions

The effect of counter-ions on the coagulation of biologically treated molasses wastewater using iron-based coagulants was investigated. Parameters such as removals of chemical oxygen demand (COD) and color, and residual turbidity, were measured to evaluate coagulation performance. Experimental results showed that ferric chloride and ferric nitrate were more effective than ferric sulfate at optimal dosages, achieving 89 to 90% and 98 to 99% of COD and color removals, respectively, with residual turbidity of less than 5 NTU. High-performance size exclusion chromatography (HPSEC) results revealed differences in the removal of the molecular weight fraction of organic compounds using iron salts. Scanning electron microscopy (SEM) showed randomly formed coagulated flocs characterized with irregular, sheet-like shapes. Nitrate and chloride counter-ions had similar effects on coagulation performance compared to sulfate. Both FeCl3 and Fe(NO3)3 yielded better results than Fe(SO4)2 under underdosed and optimum dosage conditions. Coagulation efficiency was less adversely affected in the overdosed regions, however, if sulfate rather than chloride or nitrate was present.

A novel UASB–MFC–BAF integrated system for high strength molasses wastewater treatment and bioelectricity generation

An up-flow anaerobic sludge blanket reactor–microbial fuel cell–biological aerated filter (UASB–MFC–BAF) system was developed for simultaneous bioelectricity generation and molasses wastewater treatment in this study. The maximum power density of 1410.2 mW/m 2 was obtained with a current density of 4947.9 mA/m 2 when the high strength molasses wastewater with chemical oxygen demand (COD) of 127,500 mg/l was employed as the influent. The total COD, sulfate and color removal efficiencies of the proposed system were achieved of 53.2%, 52.7% and 41.1%, respectively. Each unit of this system had respective function and performed well when integrated together. The UASB reactor unit was mainly responsible for COD removal and sulfate reduction, while the MFC unit was used for the oxidation of generated sulfide with electricity generation. The BAF unit dominated color removal and phenol derivatives degradation. This study is a beneficial attempt to combine MFC technology with conventional anaerobic–aerobic processes for actual wastewater treatment.

Variables affecting melanoidins removal from molasses wastewater by coagulation/flocculation

Coagulation/flocculation process was applied in the polishing treatment of molasses wastewater on a bench-scale. Important operating variables, including coagulant type and dosage, solution pH, rapid mixing conditions as well as the type and dosage of polyeletrolytes were investigated based on the maximum removal efficiencies of chemical oxygen demand (COD) and color, residual turbidity and settling characteristics of flocs. HPSEC was utilized to evaluate the removal of molecular weight fractions of melanoidins-dominated organic compounds. Experimental results indicate that ferric chloride was the most effective among the conventional coagulants, achieving 89% COD and 98% color eliminations; while aluminum sulfate was the least effective, giving COD and color reductions of 66% and 86%, respectively. In addition to metal cations, counter-ions exert significant influence on the coagulation performance since Cl −-based metal salts attained better removal efficiency than SO 4 2−-based ones at the optimal coagulant dosages. Coagulation of molasses effluent is a highly pH-dependent process, with better removal efficiency achieved at lower pH levels. Rapid mixing intensity, rather than rapid mixing time, has relatively strong influence on the settling characteristics of flocs formed. Lowering mixing intensity resulted in increasing settling rate but the accumulation of floating flocs. When used as coagulant aids, synthetic polyelectrolytes showed little effects on the improvement in organic removal. On the other hand, cationic polyacrylamide was observed to substantially enhance the settleability of flocs as compared to anionic polyacrylamide. The effects of rapid mixing conditions and polymer flocculants on the coagulation performance were discussed.

Comparison of Treatment Efficiencies of Fenton's Oxidation for Untreated and Biologically Treated Wastewaters

Abstract This article first presented direct applicability of Fenton's oxidation to high-strength wastewater, especially when efficiency of biological treatment for high-strength wastewater is insufficient. Fenton's oxidation was applied both to biologically pretreated molasses wastewater (BMW) and untreated molasses wastewater (MW), and the removal of color and chemical oxygen demand using chromate (CODcr) were compared between the two wastewaters. The optimum reaction time was 20 min for both BMW and MW. Neither the different dosages of Fenton's reagents nor the initial pH affected the removal ratios of CODcr and color from either BMW or MW. The maximum removal ratios of CODcr and color were approximately 90 and 97% for BMW and 88 and 98% for MW, respectively. Although these ratios are similar, the optimum H2O2 dose (g L−1)/initial CODcr (g L−1) ratio and the optimum H2O2/Fe2+ molar ratio for BMW treatment were larger than those for MW treatment. This indicates that direct Fenton treatment of MW uses le...

Performance and microbial community analysis of an anaerobic baffled reactor treating molasses wastewater

Performance and microbial community analysis of an anaerobic baffled reactor treating molasses wastewater

Stimulation of anaerobic digestion of thickened sewage sludge by iron-rich sludge produced by the fenton method

In batch mesophilic anaerobic digestion of a mixture of iron-rich sludge collected from Fenton treatment of molasses wastewater (MWW) and thickened sewage sludge from a municipal wastewater treatment plant, the methane content in the gas from the mixture was significantly higher than that from thickened sewage sludge only. When minerals in iron-rich sludge obtained by incineration were fed to thickened sewage sludge in semi-continuous experiments, the methane content obtained by digestion of thickened sewage sludge only increased approximately from 53% to 64%. These results suggest that iron-rich sludge can enhance methane production for thickened sewage sludge.

Decolorization of molasses wastewater by Lactobacillus plantarum No. PV71-1861

Lactobacillus plantarum No. PV71-1861, isolated from pickle samples in Thailand, showed the high potential for use in decolorization of molasses wastewater under both anaerobic and facultative (static) conditions. The strain showed the highest melanoidin pigment (MP) decolorization yield of 68.12% with MP solution (color intensity corresponding to an optical density of 3.5 units at 475 nm) containing 2% glucose, 0.4% yeast extract, 0.1% KH 2PO 4, 0.05% MgSO 4 · 7H 2O and initial pH of 6 under static condition at 30 °C within 7 days. But, it showed low growth and MP decolorization yields under aerobic conditions. Gel filtration chromatograms of the MP solutions showed that the small molecular weight fraction of MP solution was decolorized by the strain when the large molecular weight fraction still remained in the effluent. For application, the strain could apply to treat anaerobic treated-molasses wastewater (T-MWW) with high removal efficiency. The highest MP removal efficiencies and growth yield of 76.6% and 2.6 mg/mL, respectively, were observed with the T-MWW within 7 days of culture, and the effluent pH of the system was decreased to lower than 4.0 after 2–3 days operation.

Feasibility of using constructed wetland treatment for molasses wastewater treatment

The surface flow constructed wetland (SFCW) with Cyperus involucratus, Typha augustifolia and Thalia dealbata J. Fraser was applied to treat anaerobic treated-molasses wastewater (An-MWW) under the organic loading rates (OLRs) of 612, 696, 806, 929 and 1213 kg BOD 5 ha −1 day −1. The results showed that both removal efficiency and plant growth rate were increased with the decrease of organic loading rate (OLR). All tested-plant species could not grow under OLR of higher than 696 kg BOD 5 mg l −1 ( p > 0.05). Also, the plant-biomass of the systems was reduced by 10.4%, 26.5%, and 64.7% of initial plant-biomass under the OLR of 806, 929 and 1213 kg BOD 5 ha −1 day −1, respectively. However, all tested-plant species showed the same pattern on the plant-biomass production yield and removal efficiency. The highest SS, BOD, COD, total phosphorus, NH 4 + , NO 3 - and molasses pigments (MP) removal efficiencies of 90–93%, 88–89%, 67%, 70–76%, 77–82%, 94–95% and 72–77%, respectively were detected under the OLR of 612 kg BOD 5 ha −1 day.

Treatment of molasses wastewater by acetogenic bacteria BP103 in sequencing batch reactor (SBR) system

Acetogenic bacteria BP103 cells could be used as the absorbent for melanoidin pigment (MP) and molasses wastewater (MWW). The maximum MP adsorption yield of this strain observed from the dead (autoclaved) cell. It was two times higher than that with resting cells. However, the MP adsorption yield of the strain was 50–60% decreased by acclimatization with the media containing MP. The deteriorated cells (MP-adsorbed cells) could be recovered by washing with 0.1% SDS, 0.1% Tween 80 and 0.1 mol/L NaOH solutions. Among them, 0.1 mol/L NaOH solution was most suitable according to highest elution ability and no-effect to the MP adsorption capacity (The adsorption yield of deteriorated cell was reduced only 10% after washing three times with 0.1 mol/L NaOH solution). In SBR system, the strain showed very low MP removal yield with both molasses wastewater (MWW) from the anaerobic pond (An-MWW) and stillage from an alcohol factory (U-MWW). However, the MP removal yield was increased by supplementation with carbon sources (glucose). Also, the MP removal efficiency was increased with the increase of supplemented-glucose concentration. The highest COD, BOD 5, TKN and MP removal efficiencies of the SBR system with 10 times-diluted An-MWW solution containing 30 g/L glucose under HRT of seven days were 65.2 ± 2.5%, 82.8 ± 3.4%, 32.1 ± 0.8% and 50.2 ± 3.7%, respectively. The large molecular weight fraction of MP in both U-MWW and An-MWW solutions were rapidly removed by acetogenic bacteria BP103, while the small molecular weight fractions of MP still remained in the effluent.

電気分解を利用した糖蜜廃液の脱色処理 電極材料の影響と実用化の検討

In the decolorization treatment of molasses wastewater by electrolysis, the effect of anode material on the decolorization efficiency (η) was studied. Five soats of anode material, which are PdO, PbO2, IrO2, Pt and graphite, were certified under the electrolysis condition of wastewater from an alcohol distillery with 5% NaCl. PdO was the most effective anode. η with PdO was 750U·l·kC-1 three times larger than η with Pt, and η with graphite was 470U·l·kC-1. In order to study for practical use, the pilot scale electrolysis reactor was made with a graphite anode and a stainless steel cathode. When methane fermentation was used for pre-treatment and the treated water diluted with sea water, η was obtained the highest value. The energy balance of the glutamate wastewater treatment system which was conbined a methane fermentation, electrolysis decolorization and co-generation was estimated. The recovery electric energy from co-generation was calculated as 75% of the required electric energy for electrolysis decolorization.

Pelletization of biomass in a hybrid anaerobic baffled reactor (HABR) treating acidified wastewater

Abstract Pelletization of biomass was observed in a hydrid anaerobic baffled reactor treating molasses wastewater. The use of highly acidic molasses wastewater as substrate resulted in pelletization of the sludge within 30 days of operation. Change of substrate from acidified molasses to protein-rich molasses did not affect the process of pelletization. The biological pellets were able to grow and maintain their sludge settling-characteristics. The pellets were formed in all the three chambers of the reactor. The predominant mathanogenic bacteria observed were Methanosarcina sp. in the first chamber and Methanothrix sp. in the rest of the reactor. Other bacteria morphologically similar to Methanobrevibacter, Methanococcus and Desulfovibrio were also observed. The reactor was able to remove 73% of soluble COD (Chemical Oxygen Demand) at the loading rate of 20 kg COD/m 3 day. Methane production rates exceeded five volumes per day per unit volume of the reactor.

Application of Biofilm Kinetics to Anaerobic Fixed Bed Reactors

Two basic phenomena, reactor hydraulics and mass transport through biofilm coupled with kinetic expressions for substrate transformations were accounted for in order to describe the soluble COD removal mechanism in anaerobic fixed bed reactors. To provide necessary verification, experimental results from the long term operation of the pilot scale anaerobic reactor treating molasses wastewater were used. Theoretical evaluations verified by these experimental studies showed that a bulk zero-order removal rate expression modified by diffusional resistance leading to bulk half-order and first-order rates together with the particular hydraulic conditions could adequately define the overall soluble COD removal mechanism in an anaerobic fixed bed reactor. The experimental results were also used to determine the kinetic constants for practical application. In view of the complexity of the phenomena involved it is found remarkable that a simple simulation model based on biofilm kinetics is a powerful tool for design and operation of anaerobic fixed bed reactors.