Treatment Of Cheese Whey Wastewater Research Articles

Combined coagulation-electrocoagulation process using biocoagulant from the Opuntia ficus-indica for treatment of cheese whey wastewater.

This work reports a combined coagulation-electrocoagulation process using a biocoagulant from the Opuntia ficus-indica for treatment of cheese whey wastewater. The process parameters as pH, biocoagulant dosage, and current density were evaluated from the chemometric tools. A Box-Behnken design was used, having as responses the removal percentages of turbidity and chemical oxygen demand (COD). The results showed that for the studied variable ranges, linear models were obtained and the pH was parameter more significant for treatment proposed. The pH showed synergic effect with the investigated parameters, while the biocoagulant dosage and density current showed antagonistic effects. The desirability function was used to optimization of process, and suggested values were pH 10.0, biocoagulant dosage of 4.4g L-1, and current density of 31.5mAcm-2, which showed removals of turbidity and COD of 98.9 and 83.8%, respectively.

Combined EC/EO processes for treating goat cheese whey wastewater

The dairy industry is currently one of the most important industrial sectors in the world, and due to the high demand for products, is considered the largest source of industrial wastewater in the food sector. Whey wastewater is the most abundant liquid by-product and is characterized by a high concentration of organic load. Thus, the treatment of cheese whey wastewater before discharge is considered important. Therefore, the processes of electrocoagulation (EC), electrooxidation (EO), as well as their combination (EC/EO) have been purposefully used for the treatment of goat cheese wastewater. The main parameters (current density (mA/cm2), agitation (rpm), pH, and operating time (min)) affecting the removal efficiency of chemical oxygen demand (COD) were studied for each process. Whey effluent was treated under the optimal conditions of EC with aluminum electrodes, and EO with a boron-doped diamond electrode (BDD), removing 40.5% and 55.3% of COD, respectively. The combined use of EC/EO eliminated 82.4% of COD in a total time of 90 min. Total nitrogen (TN), chloride (Cl−), nitrate (NO3−), and phosphate (PO4−3) pollutants were also determined. The aroma profile of the raw substrate changed during the electrochemical processes. The determination of the volatile organic compounds (VOCs) in raw and treated (EC, EO, and EC/EO) goat whey wastewater was monitored using a thermal desorption unit followed by gas chromatography/mass spectrometry (TD-GC/MS) after extraction of VOCs using the HiSorb technique. Coupling electrochemical technologies increased odor emissions from goat cheese whey wastewater.

Treatment of Cheese Whey Wastewater Using an Expanded Granular Sludge Bed (EGSB) Bioreactor with Biomethane Production

Cheese whey wastewater (CWW) is the major by-product of the dairy industry. CWW is produced in large quantities, has varied characteristics and is usually disposed of. The disposal of CWW causes a negative impact on the environment of different agroindustrial areas due to the physic-chemical composition that significantly increases its high organic load and nutrients. For this reason, the aim of this work was to carry out an evaluation of the anaerobic treatability of an Expanded Granular Sludge Bed (EGSB) bioreactor as a new sustainable alternative for treatment of these effluents with bioenergy production. In this study, the bioreactor was operated under stable conditions (i.e., buffer index of 0.23 ± 0.1, pH 7.22 ± 0.4 and temperature 26.6 ± 1.4 °C) for 201 days. During evaluation the hydraulic retention time (HRT) was 6 and 8 days, and it was buffered with NaHCO3. At these conditions, the COD removal rate and biochemical methane potential (BMP) were 90, 92%; and 334, 328 mLCH4/gCOD, respectively. The evidence found in this study highlighted that the CWW is a viable substrate to be treated in the EGSB bioreactor as long as it keeps buffered. Furthermore, the process to treat the CWW in an EGSB bioreactor can be a sustainable alternative to simultaneously solve the environmental pollution that this agro-industry confronts and produce renewable and environmentally-friendly bioenergy.

Effect of isoelectric point on cheese whey wastewater treatment using a microbial electrochemical system

In this study, a microbial electrochemical system (MES) was employed to investigate the effect of isoelectric point (IEP) on cheese whey wastewater treatment. The experiments were carried out in a bioreactor equipped with a semicircular carbon cloth and stainless steel electrodes as anode and cathode, respectively. The effects of IEP, whey protein concentration, electrical current, and time were studied. The IEP of the whey protein was determined at pH 5.9. The optimum electrical current was obtained at 6 mA for synthetic cheese whey wastewater. The results of rotary exponential doping showed that the third structure of proteins chenges to the second structure at the IEP. The highest protein removal (98%) was obtained at pH 6. The results showed that 76%, 83%, and 98% protein removal were achieved at 2, 4, and 8 h, respectively.

Treatment of cheese whey wastewater by combined electrochemical processes

This study shows the good performance of a sequential electrochemical methodology, consisting in electrocoagulation (EC) followed by an electrochemical advanced oxidation process (EAOP), to treat raw cheese whey wastewater at laboratory and pre-pilot scales. In EC, different electrode materials like Fe, Al and stainless steel (AISI 304 and ASI 316L) were tested. Among EAOPs, photoelectro-Fenton (PEF) and electrochemical oxidation (EO) with active anodes like Pt or DSA® and non-active ones like boron-doped diamond (BDD) were studied. At both scales, the optimum anode/cathode combination in EC was Fe/AISI 304, which yielded the highest total organic carbon (TOC) removal of 22.0–27.0%. This is due to various effects on organic compounds: (i) coagulation promoted by Fe(OH)3 flocs, (ii) cathodic reduction, and (iii) oxidation with generated active chlorine. At small scale, the resulting wastewater was further treated by PEF at pH 3.0. The highest TOC removal was achieved using the BDD, owing to the great oxidation power of hydroxyl radicals. In contrast, total nitrogen was abated much more rapidly with active anodes because of the attack of active chlorine on N-compounds. At pre-pilot scale, the post-treatment of conditioned wastewater made by EO with a BDD/Pt flow cell combined with UVA irradiation yielded the highest TOC removal, i.e., 49.1%. The high energy consumed by the UVA lamp would be a drawback at industrial scale, which could be overcome by using sunlight.

Coating of mixed-matrix membranes with powdered activated carbon for fouling control and treatment of dairy effluent

Abstract A novel membrane configuration consisting of a powdered activated carbon mixed-matrix membrane (PAC-MMM) and PAC loading onto its surface was fabricated via a combination of wet-phase inversion and pressure deposition technique for treatment of cheese whey wastewater (CWW) as a dairy effluent. The structural and mechanical properties of the PAC-MMMs with different concentrations of PAC were characterized using field emission scanning electron microscopy, atomic force microscopy, and tensile strength analysis. Characterization of the fabricated PAC-MMMs indicated that the filtration properties were improved by increasing the PAC concentration up to 0.5 wt.%. On the basis of this result, the 0.5 wt.% PAC-MMM was selected for further modification by PAC loading on the membrane surface. The experimental results revealed that the PAC-coated MMM at optimum surface PAC loading of 30 g m−2 could remove almost 95% of the chemical oxygen demand (COD) at the initial stage of filtration. The CWW flux was 125 L m−2 h−1, while the irreversible fouling was significantly decreased compared to an un-coated MMM. High permeation flux, high mechanical properties, high organic matters removal, low fouling, and low investment costs, make the 30 g m−2 PAC-coated MMM a good candidate for treatment of dairy effluents.

Dynamic behavior of the adsorption, activated sludge and combined activated sludge-adsorption process for treatment of cheese whey wastewater

Treatment of cheese whey wastewater (CWW) in terms of chemical oxygen demand (COD) removal by adsorption, activated sludge (AS), and combination of these two processes was investigated. The equilibrium and kinetic data for adsorption of organics available in CWW onto three types of powdered activated carbons (PACs) were successfully described by hybrid Langmuir–Freundlich and pseudo-second-order models, respectively. The results indicated that AS–PAC combined system outperformed individual AS process in different COD concentrations. The most significant result was observed at the 7,500 mg/L COD concentration with the broom sorghum PAC (BSPAC) with a PAC dose of 4 g/L which could improve COD removal efficiency from 52.3% for AS to 63.8% for AS–PAC system. The most substantial result in this study was demonstration of the PAC bioregeneration mechanism in AS–PAC process. Dynamic behavior of the AS, PAC adsorption, and AS–PAC process was modeled in terms of a set of coupled differential equations. An optimization procedure was followed to obtain the model adjustable parameters that showed the desorption index (Kdes) for AS–PAC process was more than the value that was obtained for adsorption process. Also, in AS–PAC process, the maximum specific adsorption capacity of PAC decreased.

The Treatment of Cheese Whey Wastewater by Waste Activated Sludge and Optimization of Treatment Conditions with Response Surface Methodology

The biological treatments are convenient and economical methods for improving the efficiency of industrial waste water treatment. Activated sludge is the most important biological wastewater treatment processes. Batch cultures for the treatment of whey with activated sludge were optimized through response surface methodology (RSM). A second-order central composite design was applied to evaluate the effects of three independent variables (aeration time, pH and percentage of sludge volume) on COD removal percent. Optimum conditions were estimated through RSM at 23.4 h aeration time, pH=6.8 and 5.6 (%v/v) sludge volume/ wastewater volume and to achieve 38.1% COD removal. 1 (g/L) addition of PAC reduction COD until 48.7%.

Continuous electrocoagulation of cheese whey wastewater: An application of Response Surface Methodology

In this study, treatment of cheese whey wastewater was performed using a uniquely-designed continuous electrocoagulation reactor, not previously encountered in the literature. An iron horizontal rotating screw type anode was used in the continuous mode. An empirical model, in terms of effective operational factors, such as current density (40, 50, 60 mA/cm2), pH (3, 5, 7) and retention time (20, 40, 60 min), was developed through Response Surface Methodology. An optimal region characterized by low values of Chemical Oxygen Demand (COD) was determined. As a result of experiments, a linear effect in the removal efficiency of COD was obtained for current density and retention time, while the initial pH of the wastewater was found to have a quadratic effect in the removal efficiency of COD. The best fit nonlinear mathematical model, with a coefficient of determination value (R2) of 85%, was defined. An initial COD concentration of 15.500 mg/L was reduced to 2112 mg/L with a removal efficiency of 86.4%. In conclusion, it can be said that electrocoagulation was successfully applied for the treatment of cheese whey wastewater.

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.

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.

The treatment of cheese whey wastewater by sequential anaerobic and aerobic steps in a single digester at pilot scale

The treatment of reconstituted whey wastewater was performed in a 400 L digester at 20 °C, with an anaerobic digestion step, followed by a step of aerobic treatment at low oxygen concentration in the same digester. In a first set of 48 cycles, total cycle time ( T C) of 2, 3 and 4 days were tested at varying organic loading rates (OLR). The COD removal reached 89 ± 4, 97 ± 3 and 98 ± 2% at T C of 2, 3 and 4 days and OLR of 0.56, 1.04 and 0.78 gCOD L −1 d −1, respectively. The activity of the biomass decreased for the methanogenic population, while increasing by 400% for the acidogens, demonstrating a displacement in the predominant trophic group in the biomass bed. A second set of 16 cycles was performed with higher soluble oxygen concentration in the bulk liquid (0.5 mg L −1) during the aerobic treatment at a T C of 2 days and an OLR of 1.55 gCOD L −1 d −1, with a soluble COD removal of 88 ± 3%. The biomass specific activities showed a compartmentalization of the trophic group with methanogenic activity maintained in the biomass bed and a high acidogenic activity in the suspended flocs.

Computer-aided process design, economic evaluation and environmental impact assessment for treatment of cheese whey wastewater

Efficient software was used for the comparison of five alternative scenarios for the treatment of cheese whey wastewater resulting from a Cheddar cheese factory. Scenario 1 deals with a cheese whey wastewater treatment plant that produces butter, whey protein concentrate and food-grade ethanol. In scenario 2 the butter-making section is similar to the basic process (scenario 1) with some differences in the concentration of whey proteins and in the removal of residual minerals from water. In scenario 3 the plant produces Manouri (a type of cream cheese) instead of butter. In scenario 4 the plant produces two types of whey protein concentrate (WPC), namely, a rich in whey lipids (WPC 2) and the other a highly purified protein concentrate possessing improved functional properties (WPC 1). In addition a process that produces pure lactose has replaced the ethanol section. In scenario 5 the plant produces butter, whey protein isolate (WPI) containing 95% protein and hydrolyzed-isomerized whey permeate syrup (HIPS). The economic comparison has shown that scenario 3 is the most profitable due to its high net present value (NPV) and low payback period as well as to its low production rate (40% of the full production rate) at the breakeven point. The environmental impact assessment demonstrated that scenario 4 is more environmentally friendly than the others due to the absence of biomass in the effluent.