The treatment of cheese whey wastewater by sequential anaerobic and aerobic steps in a single digester at pilot scale (original) (raw)
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Ecological clarification of cheese whey prior to anaerobic digestion in upflow anaerobic filter
Bioresource Technology, 2008
Anaerobic digestion of cheese whey wastewaters (CW) was investigated in a system consisting of an ecological pretreatment followed by upflow anaerobic filter (UAF). The pretreatment was conducted to solve the inhibition problems during anaerobic treatment of CW caused by the amounts of fats, proteins and carbohydrates and to avoid the major problems of clogging in the reactor. The optimized ecological pretreatment of diluted CW induce removal yields of 50% of chemical oxygen demand (COD) and 60% of total suspended solids (TSS) after acidification by Lactobacillus paracasei at 32°C during 20 h and neutralization with lime. The pretreated CW was used to feed UAF (35°C). The effects of organic loading rate (OLR) and hydraulic retention time (HRT) on the pretreated CW anaerobic degradation were examined. The average total COD removals achieved was 80-90%. The performance of the reactor was depressed by increasing the COD concentration to 20 g/l (OLR = 4 g COD/l d) and the COD removal efficiency was reduced to 72%. Significant methane yield (280 l/kg COD removal) was obtained at an HRT of 2 days.
Cheese whey and cheese factory wastewater treatment with a biological anaerobic-aerobic process
Water Science and Technology, 1995
Research on the anaerobic treatmentof raw cheese whey started in 1990with the objective of developing a technologysuitable for medium size cheese factories that have growing disposal problems and cannot afford high investmentcosts for whey valorisation technologies (such as whey protein and lactose recovery. spray drying. ete.), In order to couple process stability and high loads. a new downflow-uptlow hybrid reactor (DUHR) has been designed. The reactor was able to reach B, values around 10 g CODeI-I.d-I, with 98% COD convertedto gas and effluentsolubleCOD valuesclose to 1,000ppm; no external additionof alkalinity is required to maintain a stable pH thaI was constantly around 6.5-6.7 in the downtlow pre-acidification chamber and around 7.5 in the bio-methanation uptlow chamber. The high strength of the cheese whey treated gives an effluent that still contains high amounts of COD, ammonia nitrogen and phosphorus and therefore a post treatmentis required in order to meet standard limits. Tests of post treatment were carried out during two years with a Sequencing Batch Reactor (SBR). The SBR was tested at various FIM values with different durations of anoxic-anaerobic-oxic cycles, obtaining. under certain conditions, more than 90% removal of COD. nitrogen and phosphorus.
Mesophilic anaerobic co-digestion of cheese whey with cow manure in batch reactor
ENP Engineering Science Journal
Anaerobic digestion is a biological process that takes place under very strict operating conditions, including a pH close to neutrality. This experimental work aims to study the effect of pH control on CH4 production in mesophilic anaerobic co-digestion of cheese whey with cow manure. Two experiments were conducted in batch reactor, the first without pH adjustment and the second with pH adjustment. The results of the first co-digestion revealed an inhibition of the methanization process by acidification of the medium and accumulation of volatile fatty acids; whereas during the second co-digestion with pH adjustment by sodium bicarbonates (1M), the process was improved with methane levels (> 50%) in the biogas. The accumulated biogas volume was two times higher for the same operating time in the digester.
Degradation of whey in an anaerobic fixed bed (AnFB) reactor
2004
An Anaerobic Fixed Bed (AnFB) reactor was run as an upflow anaerobic reactor with an arrangement of supporting material for growth of a biofilm. The supporting material was made from Liapor-clay-polyethylene sinter lamellas (Herding Co., Amberg). The AnFB reactor was used for treating high concentrations of whey-containing wastewater. Optimal operating conditions for whey treatment at a concentration of COD in the influent of around 50 g whey·l-1 were found for a hydraulic retention time (HRT) in the range of 4-8 days or an organic loading rate (OLR) less than 10 kg COD·m-3·d-1. This is a higher load than normally applied in praxis reactors. Accumulation of volatile fatty acids (VFAs) happened when the AnFB was supplied with surplus whey solution at a high OLR or when it was oxygenated. VFAs were accumulated faster when the HRT was changed from 12 days to 6 days compared to a change of HRT from 6 days to 4 days. However, at a HRT of 6 days, the accumulated VFAs were completely degra...
Waste Management, 2001
Anaerobic treatability and methane generation potential of cheese whey were determined in batch reactors. Furthermore, the effect of nutrient and trace metal supplementation on the batch anaerobic treatment, and the high-rate anaerobic treatability of cheese whey in Upflow Anaerobic Sludge Blanket (UASB) reactors were investigated. To this purpose Biochemical Methane Potential (BMP) experiments were conducted and single-and two-stage UASB reactors with granular cultures were operated. In UASB experiments significance of process staging, operational parameters such as HRT, influent Chemical Oxygen Demand (COD) concentration and loading rate were also investigated. The results revealed that nutrient and trace metal supplementaion is vital for the anaerobic treatment of cheese whey; the anaerobic methane generation for the cheese whey studied was found to be 424 mL CH 4 /g COD (23.4 L CH 4 /L cheese whey); undiluted cheese whey could be treated anaerobically at relatively short HRT values (2.06-4.95 days) without any significant stability problems; HRT values as low as 2-3 * Corresponding author, Phone: +90 312 210 58 67, Fax: +90 312 210 12 60, E.mail: goksel@metu.edu.tr 2 days can be used for the anaerobic treatment of cheese whey, with a COD removal efficiency of 95-97 % at influent COD concentration of 42700141-55100283 mg/L.
2016
Whey is the major by-product of the dairy industry, which is produced in large quantities and usually disposed off causing major environmental pollution, due to its high organic load. The objective of this work is a development of a new pretreatment and transformation of whey residues into useful organic compounds. In this study, we realize two treatments of whey; the first, a chemical treatment using sulfuric acid (H2SO4) (0.5 M) at 45C °. The second is a biological treatment using Bacillus spp. A total of 07 samples of whey effluents were collected within 07 days, and then were put into analysis. Results show the Whey Samples (WS) discharged from dairy processing industry was highly contaminated with organic compounds. The average values of chemical oxygen demand (COD) and Biological oxygen demand (BOD) were 1280 and 703 mg02/l. oil and grease concentration up to 8 mg/l was detected. The chemical treatment using sulfuric acid (H2SO4) has reduced 93 % of the COD, and 95% of the BOD...
Batch and semi-continuous anaerobic digestion of cheese whey for combined H2 and CH4 production
2014
first order kinetic model, developed to predict the behaviour of both batch and semicontinuous anaerobic digestion systems, was tested under laboratory conditions. Two and a half litre glass reactors, using cattle-dung as a feedstock, were run in both batch and semi-continuous modes in temperature-controlled water baths at 35~C. The kinetic model defined constants which could be used to evaluate both systems. The daily gas production data from the batch systems suggested that two rate constants were required to explain them : a higher rate at shorter retention times and a lower rate for longer times. The values of the kinetic rate constant defined for the semi-continuous reactors were considerably higher than those defined for the batch reactors, while the gas production constant was lower. The model offers an effective way to predict the gas production from full-scale digesters running at 35'C, although constants derived from one mode of running should not be used for the other.
Processes
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/g...
Bioconversion of cheese whey to methane in an upflow anaerobic packed bed bioreactor
Upflow anaerobic packed bed (UAPB) reactor is an upflow fixed film packed bed bioreactor that is used for rapid biotransformation of organic matter to methane. In this study, biofilm was established on seashell, packed in an UAPB bioreactor. The start-up duration for the bioreactor was 3 to 5 days while the major problem associated with normal UASB reactors is long start-up. The reactor was operated at room temperature (25°C) with various HRT of t = 6, 9, 10, 13, 16, 20 and 24 h. The organic loading was gradually increased from 1.6 to 9.9 g L-1 h-1 COD. The UAPB reactor was continuously operated for 65 d. The treatment of high organic load dairy wastewater at HRT of 6 h was conducted. Maximum biogas production of 12.4 L h-1 (6.57 mol h-1) was achieved. At HRT of 16 h, a 94.5 % of COD removal was obtained. Methane yield of 0.12 g CH 4 per g lactose at the highest OLR was achieved.
Effect of Organic Load and Alkalinity on Dairy Wastewater Biomethanation
Engenharia Agrícola
This study aimed to evaluate the effect of variations in organic load (hydraulic retention times-HRTs: from 2 to 0.5 day) and in alkalinity (NaHCO3 from 4,000 to 1,000 mg.L-1) on methane production. Biomass of sewage sludge was inoculated and stabilized on 1" polypropylene rings. The rings were immersed in the liquid phase (8.41 L) of an upflow anaerobic filter reactor (12.22 L). A solution of 5 g of whole milk powder per liter was used to simulate effluent from the dairy industry. Process effectiveness was measured by chemical oxygen demand reduction, biogas production, and biogas methane content. Biogas production started at a 2-day HRT and synthetic effluent alkalinization with 4,000 mg.L-1 NaHCO3. The best operation condition was at 1-day HRT and with the addition of 4,000 mg.L-1 NaHCO3. Biogas production reached 1.5 NL of biogas per L of reactor liquid phase, with 68% of methane and a concomitant reduction in COD of 57%.