Whey Wastewater Research Articles

Enhancing the adsorption of the proteins in the soy whey wastewater using foam separation column fitted with internal baffles

In order to promote industrialization of protein recovery from soy whey wastewater using foam separation, a novel foam separation column fitted with baffles consisting of circular disk segments placed at regular intervals in the liquid layer of the column (known as CIB in this paper) was developed to intensify the interfacial adsorption of the proteins. The column was evaluated by studying the effects of: 1. volumetric air flow rate, 2. the initial concentration of the proteins in the soy whey water, 3. the size and spacing of the disk segments on protein adsorption characteristics. The results showed that such a column could significantly intensify the adsorption of proteins. The maximum surface excess was obtained at a volumetric air flow rate of 250mL/min, a baffle spacing of 10mm and a disk segment chord length of 29.8mm. At an initial concentration of the proteins of 1.8g/L, the surface excess given by the baffled foam column was 193% higher than that given by an unbaffled column.

Impact of co-digestion on existing salt and nutrient mass balances for a full-scale dairy energy project

Anaerobic digestion of manure and other agricultural waste streams with subsequent energy production can result in more sustainable dairy operations; however, importation of digester feedstocks onto dairy farms alters previously established carbon, nutrient, and salinity mass balances. Salt and nutrient mass balance must be maintained to avoid groundwater contamination and salination. To better understand salt and nutrient contributions of imported methane-producing substrates, a mass balance for a full-scale dairy biomass energy project was developed for solids, carbon, nitrogen, sulfur, phosphorus, chloride, and potassium. Digester feedstocks, consisting of thickened manure flush-water slurry, screened manure solids, sudan grass silage, and feed-waste, were tracked separately in the mass balance. The error in mass balance closure for most elements was less than 5%. Manure contributed 69.2% of influent dry matter while contributing 77.7% of nitrogen, 90.9% of sulfur, and 73.4% of phosphorus. Sudan grass silage contributed high quantities of chloride and potassium, 33.3% and 43.4%, respectively, relative to the dry matter contribution of 22.3%. Five potential off-site co-digestates (egg waste, grape pomace, milk waste, pasta waste, whey wastewater) were evaluated for anaerobic digestion based on salt and nutrient content in addition to bio-methane potential. Egg waste and wine grape pomace appeared the most promising co-digestates due to their high methane potentials relative to bulk volume. Increasing power production from the current rate of 369 kW to the design value of 710 kW would require co-digestion with either 26800 L d−1 egg waste or 60900 kg d−1 grape pomace. However, importation of egg waste would more than double nitrogen loading, resulting in an increase of 172% above the baseline while co-digestion with grape pomace would increase potassium by 279%. Careful selection of imported co-digestates and management of digester effluent is required to manage salt and nutrient mass loadings and reduce groundwater impacts.

Growth and development of tomato plants Lycopersicon Esculentum Mill. under different saline conditions by fertirrigation with pretreated cheese whey wastewater

Pretreated cheese whey wastewater (CWW) has been used at different salinity levels: 1.75, 2.22, 3.22, 5.02 and 10.02 dS m(-1) and compared with fresh water (1.44 dS m(-1)). Two cultivars (cv.) of the tomato plant Lycopersicon Esculentum Mill. (Roma and Rio Grande) were exposed to saline conditions for 72 days. Salinity level (treatment) had no significant effects on the fresh weight and dry matter of the leaves, stems and roots. Similar results were found when specific leaf area, leaflet area, ramifications number of 1st order/plant, stem diameter and length, nodes number/stem and primary root length were considered. Conversely, the salinity level significantly influenced the Soil Plant Analysis Development (SPAD) index and the distance between nodes in the plant stem. In the first case, an increase of 21% was obtained in the salinity levels of 5.02 and 10.02 dS m(-1) for cv. Rio Grande, compared with the control run. The results showed that the pretreated CWW can be a source of nutrients for tomato plants, with reduced effects on growth and development.

PENGARUH KADAR AIR, DOSIS DAN LAMA PENGENDAPAN KOAGULAN SERBUK BIJI KELOR SEBAGAI ALTERNATIF PENGOLAHAN LIMBAH CAIR INDUSTRI TAHU

Liquid waste industrial of wheys contain very high organic materials. Organic compounds in the effluent are proteins, carbohydrates, fats and oils. Based on the results of field studies on Industry Hall of liquid waste industrial characteristics of whey in Medan, it is known that liquid waste industrial of wheys contain average BOD (4583 mg/l), COD (7050 mg/l), TSS (4743 mg/l ) and oil or fat (26 mg/l ) at pH 6.1. Therefore, the whey waste water must be treated before it is discharged into the environment to reduce the contaminants that accompany the waste. One alternative that can be used as a coagulant is moringa seed powder. This study used of moringa seed powder with a water content of 7 %. Variations of coagulant dosage which are used 2000, 3000, 4000, 5000 mg/200 ml liquid waste industrial of whey, coagulant particle size 50 and 70 mesh with the initial pH about 4. The optimum deposition time is obtained 60 minutes with 77.43 % reduction in turbidity, TSS 90.32 %, and 63.26 % COD in 5000 mg/200 ml dosage of coagulant and coagulant particle size of 70 mesh with the final pH about 4, it can be concluded that moringa seeds can be used as an effective coagulant because the reductions were obtained over 50 %.

Enhancing foam drainage using inclined foam channels of different angles for recovering the protein from whey wastewater

For comprehensive knowledge of enhancing foam drainage using the inclined foam channel (IFC), the effect of the tilt angle was investigated experimentally and theoretically with the diluted whey wastewater as the model system. The IFC allowed the interstitial liquid to release quickly to its wall and then returned the liquid phase along it. The theoretical analysis presents that the velocity for the drained liquid reflux increased with increasing the tilt angle from 0° to 45° and then decreased. The net liquid flux in the IFC decreased to its minimum at 45° and then increased. Thus the IFC of the tilt angle 45° had the greatest ability to enhance foam drainage. The experimental results consisted well with the theoretical analysis. The IFC of the tilt angle 45° was adopted to improve the protein enrichment ratio and its performances were evaluated under various conditions. Under the suitable conditions, a best protein enrichment ratio of 10.2 was achieved using the IFC of 45°, which was 1.93 times of that obtained using the vertical column.

Simultaneous hydrogen gas formation and COD removal from cheese whey wastewater by electrohydrolysis

Cheese whey (CW) was subjected to DC voltages between 0.5 and 5 V for hydrogen gas production with simultaneous COD removal by electrohydrolysis of CW organics. Hydrogen gas formation and COD removal were investigated at different DC voltages using aluminum electrodes. The highest cumulative hydrogen production (5551 mL), hydrogen yield (1709 mL H2 g−1 COD), hydrogen gas formation rate (913 ml d−1), and percent hydrogen (99%) in the gas phase were obtained with 5 V DC voltage within 158 h. Energy conversion efficiency reached the highest level (80.7%) at 3 V DC voltage with cumulative hydrogen production of 4808 mL and hydrogen yield of 1366 mL H2 g−1 COD. Hydrogen gas was mainly produced by electrohydrolysis of CW organics due to low H2 gas production in water and CW control experiments. The highest COD removal (22%) was also obtained with 3 V DC voltage. Major COD removal mechanism was anaerobic degradation of carbohydrates producing volatile fatty acids (VFA) and CO2. Hydrogen gas was produced by reaction of protons released from VFAs and electrons provided by DC current. Hydrogen gas production by electrohydrolysis of CW solution was proven to be an effective method with simultaneous COD removal.

Enhanced electricity generation from whey wastewater using combinational cathodic electron acceptor in a two-chamber microbial fuel cell

While energy consumption is increasing worldwide due to population growth, the fossil fuels are unstable and exhaustible resources for establishing sustainable life. Using biodegradable compounds present in the wastewater produced in industrial process as a renewable source is an enchanting approach followed by scientists for maintaining a sustainable energy production to vanquish this problem for ulterior generations. In this research, bioelectricity generation with whey degradation was investigated in a two-chamber microbial fuel cell with humic acid as anodic electron mediator and a cathode compartment including combinational electron acceptor. Escherichia coli was able to use the carbohydrate originated from whey to generate bioelectricity. The open-circuit potential in absence of mediator was 751.5 mV at room temperature. The voltage was stable for more than 24 h. Humic acid was used as a suitable mediator. In addition, some mixed chemicals were employed as catholyte. Based on polarization curve, the power and current values in the presence of a mixed solution of potassium iodide (KI), ferric chloride [FeCl3 (Ш)] and manganese chloride tetrahydride (MnCl2·4H2O) with doubling of oxidant (oxygen) concentration using agitation with magnet stirrer in cathode compartment without any buffer solution were boosted to 562.9 μW and 1906.1 μA, respectively, and demonstrated the best result for power generation.

Specific energy consumption in electrochemical treatment of food industry wastewaters

AbstractBACKGROUND: Specific energy consumption (SEC) is an important factor in electrochemical treatment of wastewaters. SEC during electrochemical treatment of food industry wastewaters, specifically deproteinated whey wastewater (DWW), simulated sugar beet factory wastewater (SFW) and fruit juice factory wastewater (FJW), were investigated in this study. The effects of operational parameters applied voltage, and electrolyte and wastewater concentrations on SEC were assessed and optimized.RESULTS: SEC values were found in the range of 0.27–148.65, 0.94–375.76 and 0.20–636.40 kWh (kg COD)−1 for DWW, SFW and FJW, respectively, after 8 h of reaction. Operational parameters were optimized at 25 °C through response surface methodology (RSM) where applied voltage was kept in the range (2–12 V), wastewater concentration and COD removal percent were maximized electrolyte concentration and SEC were minimized. Optimum conditions were estimated as 7.73 V applied voltage and 100% wastewater concentration in the presence of 27.11 g L−1 supporting electrolyte concentration to achieve 25.02, 67.74 and 43.10% COD removal for DWW, SFW and FJW with corresponding SEC values of 17.85, 22.79 and 80.47 kWh (kg COD)−1, respectively.CONCLUSIONS: Providing further research on the reduction of SEC values, application of electrochemical treatment to food industry wastewaters with non‐biodegradable components may become an alternative to conventional methods. Copyright © 2012 Society of Chemical Industry

Biohydrogen Production from Cheese Whey Wastewater in a Two-Step Anaerobic Process

Cheese whey-based biohydrogen production was seen in batch experiments via dark fermentation by free and immobilized Enterobacter aerogenes MTCC 2822 followed by photofermentation of VFAs (mainly acetic and butyric acid) in the spent medium by Rhodopseudomonas BHU 01 strain. E. aerogenes free cells grown on cheese whey diluted to 10 g lactose/L, had maximum lactose consumption (∼79%), high production of acetic acid (1,900 mg/L), butyric acid (537.2 mg/L) and H(2) yield (2.04 mol/mol lactose; rate,1.09 mmol/L/h). The immobilized cells improved lactose consumption (84%), production of acetic acid (2,100 mg/L), butyric acid (718 mg/L) and also H(2) yield (3.50 mol/mol lactose; rate, 1.91 mmol/L/h). E. aerogenes spent medium (10 g lactose/L) when subjected to photofermentation by free Rhodopseudomonas BHU 01 cells, the H(2) yield reached 1.63 mol/mol acetic acid (rate, 0.49 mmol/L/h). By contrast, immobilized Rhodopseudomonas cells improved H(2) yield to 2.69 mol/mol acetic acid (rate, 1.87 mmol/L/h). The cumulative H(2) yield for free and immobilized bacterial cells was 3.40 and 5.88 mol/mol lactose, respectively. Bacterial cells entrapped in alginate, had a sluggish start of H(2) production but outperformed the free cells subsequently. Also, the concomitant COD reduction for free cells (29.5%) could be raised to 36.08% by immobilized cells. The data suggest that two-step fermentative H(2) production from cheese whey involving immobilized bacterial cells, offers greater substrate to- hydrogen conversion efficiency, and the effective removal of organic load from the wastewater in the long-term.

Technology of protein separation from whey wastewater by two-stage foam separation

For recovering the proteins from the whey wastewater, a two-stage foam separation technology was developed with the column of inclined foam phase. Effects of inclined angle, initial pH, volumetric air flow rate and temperature on the performances of the wastewater were investigated. The results showed that when the conditions of the first stage were protein concentration 4.0 g/L, initial pH 7, inclined angle 50°, volumetric air flow rate 100 mL/min and temperature 50 °C, enrichment ratio of the proteins was 8.5 and the residual solution went into the second stage as the feeding stream. When the conditions of the second stage were temperature 20 °C and volumetric air flow rate 200 mL/min, recovery percentage of the proteins reached 70%, the foamate was added to the wastewater as the feeding stream of the first stage. Total recovery percentage of the proteins reached to 80% by the two-stage foam separation.

Treatment of whey wastewater by supercritical water oxidation

Whey wastewater is a by-product of cheese industry, which causes environmental pollution problems due to its containment of heavy organic pollutants. Conventional methods such as biological treatment and physico-chemical treatment are insufficient or ineffective. In this paper, the treatment of cheese whey wastewater has been carried out by supercritical water oxidation, using hydrogen peroxide as oxidant. The reaction conditions ranged between temperatures of 400-650°C and residence times of 6-21 s under a pressure of 25 MPa. Treatment efficiencies based on TOC removal were obtained between 75.0% and 99.81%. An overall reaction rate model, which consists of the hydrothermal and the oxidation reactions, was determined for the hydrothermal decomposition of the wastewater with an activation energy of 50.022 (±1.7) kJmol(-1) and a pre-exponential factor of 107.72 (±4.1) s(-1). The oxidation reaction rate orders for the TOC and the oxidant were 1.2 (±0.4) and 0.4 (±0.1) respectively, with an activation energy of 20.337 (±0.9) kJmol(-1), and a pre-exponential factor of 1.86 (±0.5) mmol(-0.6)L(0.6)s(-1) in a 95% confidence level.

Aerobic Biodegradation of Precoagulated Cheese Whey Wastewater

Prior to the application of an aerobic biological process, cheese whey wastewater has been pretreated by means of a precipitation stage by adding either NaOH or CaOH2. Both precipitating agents reduce roughly 50% of the raw wastewater chemical oxygen demand (COD). The sludge generated in the prestage shows acceptable settling properties, although solids from the CaOH2-treated effluent are better separated from the liquid bulk than those formed in NaOH-processed wastewater. In both situations, the presedimentation stage renders a supernatant more prone to biodegradation than the untreated effluent. The previous statement is corroborated by the determination of some biological kinetic parameters. Under the operating conditions used in this work, sludge generation after the biological process is reduced to a minimum. The sludge generated shows good settling properties, especially for those experiments in which CaOH2 has previously been added.

Final Remediation of Post-Biological Treated Milk Whey Wastewater by Ozone

This work deals with a real environmental problem related with milk whey wastewater. Even if a high depuration degree can be achieved using aerobic biological processes, the final effluent does not accomplish the legal regulation for disposal. In this context, we studied the application of ozone oxidation after an activated sludge treatment in order to obtain an effluent suitable to be discharged into the natural water courses. Even if the pH increase improved single ozonation efficiency, the treated wastewater was not yet able to be disposed of. The introduction of hydrogen peroxide at low concentrations enhanced the ozone action over the pollutants, and this combination led to residual water within the environmental law conditions to be released on the surroundings. Furthermore, heterogeneous catalytic ozonation over Mn-Ce-O 70/30 (prepared in our laboratory) and the commercial N-150 catalyst (Fe2O3-MnOx) was very efficient on the wastewater depuration. Nevertheless, the high amount of carbon adsorbed on the recovered catalysts disable the industrial implementation of this technology.

Treatment of Cheese Whey Wastewater: Combined Coagulation−Flocculation and Aerobic Biodegradation

Cheese wastewater has been treated by means of a coagulation-flocculation process. Three different coagulants have been used, namely, FeSO(4), Al(2)(SO(4))(3), and FeCl(3). When FeSO(4) was used, the optimum conditions were obtained using 250 ppm of the salt at pH 8.5. At these conditions, 50 and 60% of chemical oxygen demand (COD) and biological oxygen demand (BOD) were reduced, respectively. Al(2)(SO(4))(3) achieved slightly lower reductions of COD and BOD; however, the amount needed was significantly higher (1000 ppm). When FeCl(3) was added, similar results to those obtained with FeSO(4) were experienced; again, 250 ppm was enough to eliminate COD and BOD contents in the range of 40-60%, depending upon operating conditions. The sludge formed in the coagulation-flocculation process did show acceptable settling properties, which is crucial in settling tank design. A first approach to sedimentation tank design is also conducted on the basis of experimental results. The aerobic biodegradation of cheese whey wastewater achieves the reduction of the main contaminant indicators (COD and BOD) to values close to 100%; however, effluents coming from the coagulation-flocculation pre-stage necessitate half of the time required by the non-pretreated raw wastewater.

Proton transfer reaction time‐of‐flight mass spectrometry monitoring of the evolution of volatile compounds during lactic acid fermentation of milk

We apply, for first time, the recently developed proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) apparatus as a rapid method for the monitoring of lactic acid fermentation (LAF) of milk. PTR-TOF-MS has been proposed as a very fast, highly sensitive and versatile technique but there have been no reports of its application to dynamic biochemical processes with relevance to the food industry. LAF is a biochemical-physicochemical dynamic process particularly relevant for the dairy industry as it is an important step in the production of many dairy products. Further, LAF is important in the utilization of the by-products of the cheese industry, such as whey wastewaters. We show that PTR-TOF-MS is a powerful method for the monitoring of major volatile organic chemicals (VOCs) formed or depleted during LAF, including acetaldehyde, diacetyl, acetoin and 2-propanone, and it also provides information about the evolution of minor VOCs such as acetic acid, 2,3-pentanedione, ethanol, and off-flavor related VOCs such as dimethyl sulfide and furfural. This can be very important considering that the conventional measurement of pH decrease during LAF is often ineffective due to the reduced response of pH electrodes resulting from the formation of protein sediments. Solid-phase microextraction gas chromatography/mass spectrometry (SPME-GC/MS) data on the inoculated milk base and final fermented product are also presented to supporting peak identification. We demonstrate that PTR-TOF-MS can be used as a rapid, efficient and non-invasive method for the monitoring of LAF from headspace, supplying important data about the quality of the final product and that it may be used to monitor the efficacy of manufacturing practices.

Fenton's Process for Post-Biologically Treated Cheese Production Wastewaters Final Remediation. Toxicity Assessment

The use of the Fenton's process for the depuration of a post-biological treated milk whey wastewater was studied, aiming to achieve adequate operational conditions for a cost effective treatment to generate a suitable effluent to be directly discharged into the natural water courses. A design of experiments was implemented in order to understand the role of the independent parameters and their combinations over the treatment process. From our results the hydrogen peroxide concentration and the ratio between [H2O2]:[Fe2+] as well as their interaction were statistically important concerning both TOC and COD removal. The experiments performed at the highest value of [H2O2] and at the lowest level of [H2O2]:[Fe2+] lead to effluents accomplishing the environmental legislation. Moreover, toxicological tests revealed that the treated effluent was harmless to the ecosystems. A cost estimation analysis was performed and the catalytic activity of the remaining sludge from the homogeneous process was checked. This activity decreases with the number of reuses which reduces the possibility of the direct utilization of the sludge.

Production and characterization of biosurfactants produced by microorganisms isolated from milk factory wastewaters

Biosurfactants or surface‐active compounds are produced by microorganisms. These molecules reduce the surface tension of both aqueous solutions and hydrocarbon mixtures. In this study, the isolation and identification of biosurfactant‐producing microorganisms were assessed. The characterization of biosurfactant produced by microorganisms isolated from milk factory wastewaters was investigated. For this purpose, five different microorganisms were isolated and identified. In order to determine the biosurfactant production, the ‘drop‐collapse’ method was applied and it was determined that only three species, Yarrowia lipolytica MFW5 (yeast), Micrococcus luteus MFW1 (cocci) and Burkholderia cepacia MFW2 (bacillus), were able to produce biosurfactant. Biosurfactants produced by Yarrowia lipolytica, Micrococcus luteus and Burkholderia cepacia were coded as BS‐I, BS‐II and BS‐III, respectively. After the initial biosurfactant production and characterization studies were completed, isolates of these three species were incubated with whey wastewaters at 35°C for 10 days for biosurfactant production. At the end of the incubation period, the biosurfactants were extracted and further characterized with biochemical analysis, FTIR spectra, haemolysis test, emulsification test and determination of the surface tension.

The effect of dilution and l-malic acid addition on bio-hydrogen production with Rhodopseudomonas palustris from effluent of an acidogenic anaerobic reactor

In this study, H 2 was produced from cheese whey wastewater in a two-stage biological process: i) first stage; thermophilic dark fermentation ii) second stage; the photo fermentation using Rhodopseudomonas palustris strain DSM 127 ( R. palustris). The effect of both dilution and addition of l-malic acid on the hydrogen production was investigated. Among the dilution rates used, 1/5 dilution ratio was found to produce the best hydrogen production (349 ml H 2/g COD fed). On the other hand, It was seen that the mixing the effluent with l-malic acid at increasing ratios had further positive effect and improved the hydrogen production significantly. It was concluded that dilution of the feeding helps to reduce the nitrogen content and the volatile fatty acid content that might be otherwise harmful to the photo-heterotrophic organisms. Overall hydrogen production yield (for dark + photo fermentation) was found to vary 2 and 10 mol H 2/mol lactose. Second conclusion is that cheese whey effluent should be mixed with a co-substrate containing l-malic acid such as apple juice processing effluents before fed into the photo fermentation reactor.

Optimization of Basal Medium for Fermentative Hydrogen Production from Cheese Whey Wastewater

In this study, optimal basal medium composition for fermentative hydrogen production from cheese whey wastewater was investigated in batch tests. Twenty-five different basal medium formulas was prepared, each containing trace metals concentration (Co, Ni, Zn: 0–5 mg/l), macro elements concentration (Mg: 0–200 mg/l; Mn: 0–10 mg/l, Fe: 0–100 mg/l, Ca: 0–1000 mg/l), C/N ratio of 5–50, and yeast extract and l-cycteine concentrations (0–500 mg/l). Each of the experimental setups was conducted as triplicates in 100-ml serum vials at pH 5.5 under mesophilic conditions (36 ± 1°C). Granular biomass obtained from an industrial scale upflow anaerobic sludge bed bioreactor was used as an initial inoculum. Considering the hydrogen production efficiencies obtained in this study (max. 3.5 mol H2/mol lactoseconsumed and 218.6 ml H2 /g lactoseconsumed), a successful nutrient formulation for optimum hydrogen production from cheese whey was proposed as follows; CoCl2, NiCl2, ZnCl2: 1.25–2.5 mg/l; CaCl2: 250–500 mg/l: MgCl2: 50–150 mg/l; MnCl2: 2.5–5 mg/l; FeCl2: 50–100 mg/l; yeast extract: 125–250 mg /l; L-cysteine: 125–250 mg /l and C/N ratio: 30–40.

Continuous fermentative hydrogen production from cheese whey wastewater under thermophilic anaerobic conditions

Hydrogen (H2) production from cheese processing wastewater via dark anaerobic fermentation was conducted using mixed microbial communities under thermophilic conditions. The effects of varying hydraulic retention time (HRT: 1, 2 and 3.5 days) and especially high organic load rates (OLR: 21, 35 and 47 g chemical oxygen demand (COD)/l/day) on biohydrogen production in a continuous stirred tank reactor were investigated. The biogas contained 5–82% (45% on average) hydrogen and the hydrogen production rate ranged from 0.3 to 7.9 l H2/l/day (2.5 l/l/day on average). H2 yields of 22, 15 and 5 mmol/g COD (at a constant influent COD of 40 g/l) were achieved at HRT values of 3.5, 2, and 1 days, respectively. On the other hand, H2 yields were monitored to be 3, 9 and 6 mmol/g COD, for OLR values of 47, 35 and 21 g COD/l/day, when HRT was kept constant at 1 day. The total measurable volatile fatty acid concentration in the effluent (as a function of influent COD) ranged between 118 and 27,012 mg/l, which was mainly composed of acetic acid, iso-butyric acid, butyric acid, propionic acid, formate and lactate. Ethanol and acetone production was also monitored from time to time. To characterize the microbial community in the bioreactor at different HRTs, DNA in mixed liquor samples was extracted immediately for PCR amplification of 16S RNA gene using eubacterial primers corresponding to 8F and 518R. The PCR product was cloned and subjected to DNA sequencing. The sequencing results were analyzed by using MegaBlast available on NCBI website which showed 99% identity to uncultured Thermoanaerobacteriaceae bacterium.