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The aim of this work is to fabricate a low‐cost ceramic microfiltration (MF) membrane made from a new geomaterial named peridotite. The membrane was prepared by uniaxial pressing and followed by sintering. The effect of sintering temperature, in the range of 1100–1225°C, on the permeability, porosity, mechanical strength, and pore size was investigated. The optimized MF membrane sintered at 1200°C exhibits 1198.9 L h−1 m−2 bar−1 of permeability, 36.41% of porosity, 12.9 MPa of mechanical strength, and 1.56 µm of pore size. The prepared membrane was used for the MF treatment of dairy wastewater. It was found that the membrane is able to remove 88.56% and 69.54% of turbidity and chemical oxygen demand, respectively. Furthermore, the cost of the peridotite membrane was estimated to be $10.3 m−2. [ABSTRACT FROM AUTHOR]

AbstractThis study explores a novel enzymatic pretreatment approach in anaerobic reactors for dairy wastewater, using lipase AY Amano to enhance methane production and modify microbial and archaeal community composition. Batch and semi-batch reactors with a total volume of 2000 mL were used to treat dairy wastewater with initial COD of 2000 and 15,000 mg L−1, respectively. In a new novel approach, the semi-batch reactors underwent a three-phase operation: 30 days of acclimation, 30 days of rest, and 30 days of active operation. Adding lipase (0.05% wv−1) as a pretreatment significantly increased methane yield over the 90 days by 135–138% compared with the control (without enzyme addition). The organic loading rate reached 0.22 g COD day−1 L−1. Furthermore, 30 days after the end of the semi-batch reactor approach (120 days from the start), reusing sludge in batch reactors increased methane yield by 114–122% compared to the control. This increase was linked to the emergence and shift of new methanogenic communities within the sludge. Integrating hydrolytic enzymes into the anaerobic treatment enhances performance and sustainability by fostering methanogen-enriched microbial communities. This is crucial for maximizing methane production but may increase costs, requiring further economic feasibility research. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the combined two‐stage biological‐treatment‐process using consortium of bacteria and microalgae for removal of soluble chemical oxygen demand (SCOD), ammonium‐nitrogen (NH4+‐N), nitrate‐nitrogen (NO3−‐N), phosphorus (PO43−‐P) from dairy wastewater in suspended‐growth batch‐reactor (SGBR). The study also investigated the removal of SCOD, NH4+‐N, NO3−‐N, PO43−‐P under different process parameters, like initial SCOD, NH4+‐N,NO3−‐N, PO43−‐P, MLSS, pH and react time using response surface methodology (RSM) with a five‐factor‐three‐level Central Composite Design(CCD). The experimental results were analyzed by ANOVA and second‐order polynomial mathematical‐models were developed with high correlation efficiency for SCOD, NH4+‐N removal, NO3−‐N, PO43−‐P removal using bacterial and microalgal‐consortia respectively in SGBR. Individual and combined effects of process variables on responses were studied using three‐dimensional response surface plots. Under the optimum conditions (initial SCOD, NH4+‐N, pH, MLSS of 720 mg L−1, 55 mg L−1 as N, 7 and 1500 mg L−1, respectively and react time of 24 h) highest removal efficiencies of SCOD (98.61%) and NH4+‐N (97.42%) were obtained using bacterial consortium and in second‐phase using micro‐algal consortium under optimum conditions highest removal efficiencies of nitrate nitrogen and phosphorus 98.64% and 90.53%, respectively. Optimization of process‐parameters by RSM study is supposed to be helpful for the treatment of real life dairy wastewater in effluent treatment plants. [ABSTRACT FROM AUTHOR]

Dairy industry wastewater can be considered as an important source of pollution due to its high amounts and pollutant concentrations. Anaerobic treatment is seen as a suitable alternative over aerobic treatment which requires huge aeration systems. Biochemical methane potential (BMP) testing is a widely applied technique for estimating the performance of anaerobic digesters and still has no clear alternative. In the study, the biochemical methane potential change was investigated by mixing dairy wastewater with different co-substrates (cattle manure, chicken manure and slaughterhouse wastewater) at different rates. The highest biogas potential per gram of chemical oxygen demand added (CODadded) was determined as 574 mLbiogas in a mixture of 74% dairy wastewater + 2% chicken manure + 24% slaughterhouse wastewater inoculated with granular sludge. The highest methane potential was determined as 340 mLCH4 in the same co-substrate mixture inoculated with anaerobic sludge. In recent years, mathematical modeling offers an alternative to BMP tests and many different models are used for this purpose. In the study, six different mathematical models were used to simulate the BMP results, and the highest correlation coefficient in almost all mixtures ranged from 0.900 to 0.997 with the Modified Gompertz equation and Fitzhugh models. [ABSTRACT FROM AUTHOR]

The dairy industry is among the most contaminated of the food industries. Dairy industry wastewater contains a high organic load and chemical oxygen demand (COD). In recent years, due to the development of the dairy industry, the administration of dairy effluents has become the main problem since dairy effluents can be a dangerous and significant threat, especially to the aqueous environment. Therefore, there is an important need to improve the management and remediation of dairy effluents in order to ensure the economic viability of this major agricultural industry and to decrease environmental problems. Several works focused on the remediation of dairy wastewater. In this study, the effect of the electro-Fenton process on COD and turbidity removal from dairy wastewater was studied. The electro-Fenton process was optimized for four independent variables (pH, reaction time, volume of H2O2, and H2O2/Fe2+ (the molar ratio)). Moreover, the response surface methodology was utilized to design experiments and determine optimum operating conditions. Under optimal conditions (pH = 5.95, reaction time = 60 min, volume of H2O2 = 1.5 ml and the molar ratio of H2O2/Fe2+ = 1.8), the removal efficiency of COD was 95.8%. Also under optimal conditions (pH = 6.37, reaction time = 60 min, volume of H2O2 = 1.5 ml and the molar ratio of H2O2/Fe2+ = 2.09), the removal efficiency of turbidity was 97.2%. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFC) are emerging technologies that can produce electricity while treating wastewater. A series of tests were carried out to evaluate the efficiency of this technology for treating dairy wastewater (DWW). The experiments used Shewanella baltica as an exoelectrogen in a small single MFC to treat simulated DWW. The impacts of various operational factors, specifically pH, hydraulic retention time (HRT), and chemical oxygen demand (COD) in the influent to the anode chamber, were investigated, and the effect of these variables on the output performance of the cell was evaluated. The best performance of the MFC was found when the pH, HRT, and COD were 8, 6.66 h, and 20,632 mg/L, respectively, in the scaled experimental setup. Under these conditions, the maximum power density and percentage removal of COD in terms of wastewater treatment ability were found to be 138 mW/m2 and 71%, respectively. It may be concluded that MFCs are suitable treatment technologies for treating dairy wastewater while potentially simultaneously generating power. [ABSTRACT FROM AUTHOR]

To investigate the feasibility of livestock wastewater purification by the floating plant Pistia stratiotes L., an experimental study was conducted using P. stratiotes L. treatments of dairy wastewater to clarify the growth status and physiological responses of P. stratiotes L. in different types of wastewater and investigate the purifying effects on nitrogen, phosphorus, and organic matter. The changes in microbial communities were also analyzed using high-throughput sequencing to reveal the relationship between microbial communities and the removal of conventional pollutants. The results showed that the tolerance ranges were 0-2 000 mg·L-1 and 0-750 mg·L-1 for raw and anaerobic and oxidized pond wastewater, respectively[measured as chemical oxygen demand(CODCr)]. When P. stratiotes L. was subjected to high concentrations of wastewater, the chlorophyll content was markedly reduced, and the activities of three enzymes(catalase, peroxidase and superoxide dismutase) were significantly increased. Within the tolerance range, P. stratiotes L. showed good purification effects on the three wastewater types from dairy farms. Pistia stratiotes L. had a rapid purification speed in the first 10 days, which slowly inecreased within 10-20 days. After treatment with P. stratiotes L., the removal rates of total nitrogen, ammonia nitrogen, total phosphorus, and CODCr in raw wastewater were 84.7%-92.7%, 90.6%-96.7%, 30.0%-93.1%, and 67.3%-77.2%, respectively; however, the purification effect of P. stratiotes L. in anaerobic and oxidation ponds decreased slightly. Regarding the microbial communities, Proteobacteria, Firmicutes, and Bacteroidetes, were the main species in different dairy wastewaters. The microbial community structures in the P. stratiotes L. treatment group and non-plant control group were significantly different; in particular, the relative abundance of Cyanobacteria was distinct. The correlation between the microbial community and several indexes of wastewater was significant(P<0.05), indicating that microorganisms played an important role in the removal of pollutants. This study verified the feasibility of P. stratiotes L. in treating wastewater with high concentrations of pollutants and provides a theoretical basis and technical support for dairy farm wastewater treatment. [ABSTRACT FROM AUTHOR]

Background: The adequate management of dairy effluent is of prime importance to mitigate environmental damages. In addition, its adequate treatment could enable its reuse inside the dairy industry, contributing to a sustainable economy. Results: The optimization of the coagulation/ flocculation/ sedimentation stage through a Box–Behnken Design was proposed using real dairy effluent and natural coagulant of Moringa extracted with CaCl2. Then, nanofiltration with a NF 270 membrane was applied, using the raw wastewater and the wastewater pre‐treated with coagulation/ flocculation/ sedimentation, enabling apparent color and turbidity removals of >98% in the three studied conditions. A satisfactory chemical oxygen demand (COD) removal of 88.9% was obtained only with the combination of the pre‐treatment by coagulation/ flocculation/ sedimentation followed by nanofiltration. When the effluent was subjected to nanofiltration directly, the COD removal did not reach 61%. Besides improving the removal values, the pre‐treatment improved the transmembrane flow, reducing the fouling and the membrane total resistance when compared to the dairy wastewater directly subjected to nanofiltration. Conclusion: When the wastewater was pre‐treated using the natural coagulant, the nanofiltration stage was improved because the membrane presented a lower fouling (~10%), lower total resistance and less calcium build‐up compared to direct nanofiltration of the wastewater (~60%). This indicates that the membrane lifespan can be extended when the pre‐treatment is applied. The quality evaluation of the treated effluent demonstrated that it presents the potential to be reused inside the dairy industry, which could greatly contribute to a sustainable and economic scenario. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The aim of this study is to synthesise SPEEK composite proton exchange membrane with the addition of TiO2 nanofillers for microbial fuel cell application. SPEEK composite membrane with varying weight percentage of TiO2 (2.5, 5, 7.5 and 10%) was prepared to study the effect of TiO2 concentration on membrane performance. Synthesized composite membranes were subjected to various characterization studies such as FT-IR, XRD, Raman spectroscopy, TGA, UTM and SEM. Physico-chemical properties of membrane such as water uptake capacity, ion exchange capacity and thickness were also analyzed. 5% TiO2 – SPEEK composite membrane exhibited the higher water uptake capacity value and Ion exchange capacity value of 31% and 1.71 meq/g respectively. Performance of the MFC system with TiO2 – SPEEK membranes were evaluated and compared with the pristine SPEEK and Nafion membrane. 5% TiO2 – SPEEK membrane produced the higher power density (1.22 W/m2) and voltage (0.635 V) than the other membranes investigated. Efficacy of MFC in wastewater treatment was evaluated based on the chemical oxygen demand (COD), total organic carbon content and turbidity. Biofilm growth over the surface of the electrodes was also analyzed using scanning electron microscopy. HIGHLIGHTS Use of TiO2 – SPEEK composite membrane as alternate for the Nafion 117.; Energy generation from dairy wastewater was investigated using dual chambered MFC.; Low cost membrane.; Green energy.; TiO2 – SPEEK can be used to overcome drawbacks of Nafion 117.;

Dairy wastewater is one of the most polluted wastewaters due to its high organic load and treating this wastewater is less costly than compensating for eco-system damage. This study aimed to investigate the simultaneous effect of operating conditions on the performance of an anaerobic filter reactor (AFR) in treating dairy wastewater of Kanyar Company (Quchan, Iran). At first, to eliminate the oily materials, the wastewater entered the American Petroleum Institute (API) grease trap pilot; then, the effects of changing parameters, such as hydraulic retention time (HRT), temperature, and pH, on reactor performance were investigated. Response surface methodology was applied to design the experiments of system operating conditions. According to the results, the concentration of oil & grease decreased in the API pretreatment. Further, results indicated that temperature, HRT, and pH were effective on the quality of the AFR performance. In addition, according to the design of experiments results, it was found that only the interaction of HRT and temperature affects the performance of the reactor and should be controlled. Also, on the reactor optimum operating condition, the rate of chemical oxygen demand (COD) removal efficiency was 82%. Finally, this research showed that about 35% COD removal was performed in the first chamber. [ABSTRACT FROM AUTHOR]

Fast and proper treatment of dairy wastewater is necessary before discharging it to the environment. In this study, healthy Azolla filiculoides was used to remove pollutants, including phosphorus (P), sodium (Na), chemical oxygen demand (COD), biological oxygen demand (BOD), and total dissolved solids (TDS) of dairy effluent in batch, continuous system, as well as continuous with the slow stirring system. These systems were handmade. The maximum removal efficiency was related to the P, which obtained 66.25% after 12 h in the batch bioreactor system. The highest removal of 13.69% after 21 h was obtained for Na using continuous with a slow stirring method. The highest removal related to the COD and BOD was 33.53% and 29.93% after 18 h, respectively, in continuous with the slow stirring system. TDS removal was achieved 31.44% after 24 h using the batch system. The results of these three systems were compared with each other using a one‐way analysis of variance (ANOVA). There was no significant difference between them. Azolla filiculoides is an abundant plant in northern nature that a biosystem was used for optimum usage. It can be used as an efficient, inexpensive, and affordable bioadsorbent for dairy wastewater treatment. Practitioner points: Live Azolla filiculoides was used to remove pollutants.P, Na, BOD, COD, and TDS were removed from dairy wastewater.Batch, continuous, and continuous with the slow stirring systems were used.Live Azolla was an efficient, inexpensive, and affordable bio‐adsorbent for dairy wastewater treatment. [ABSTRACT FROM AUTHOR]

In recent years, the application of moving bed biofilm reactor (MBBR) in the biological treatment of municipal and industrial wastewater has been developed. Herein, following the construction of the MBBR reactor, the effect of three important parameters of temperature, hydraulic retention time (HRT), and pH simultaneously on the MBBR efficiency was investigated. The effluent wastewater of the anaerobic unit of Kanyar Dairy Company located in Quchan – Iran was treated as the model wastewater. Response surface methodology was applied to design the experiments of system operating conditions. The analysis of variance was applied to determine the most important parameters affecting the performance of the MBBR reactor in order to increase the chemical oxygen demand (COD) removal percentage. The amount of COD was measured as the process response. Based on the results and the analysis of variance, the response of the experiments was in accordance with the predicted model. The p-value in all the three parameters of temperature, HRT, and pH was less than 0.05, therefore making them important while having a significant effect on the performance of the reactor. Moreover, only the interaction of HRT and pH affects the performance of the reactor and should be controlled. Under the optimal conditions (pH = 7, temperature = 27°C, and HRT = 11 h), COD removal efficiency reached 93%. According to the results, an optimized MBBR is a good option for dairy wastewater treatment. [ABSTRACT FROM AUTHOR]

Dairy industrial wastewater is characterized by high chemical oxygen demand (COD) and other pollution loads. In this study, simulated dairy wastewater (SDW) was treated for turbidity and COD elimination via electrocoagulation (EC) with aluminum electrodes. COD concentration was not completely abated and exceeded allowable Algerian direct discharge limits. To enhance rate parameter pollution removal, electrocoagulation (EC) was combined with adsorption (AD) under the same operational electrocoagulation conditions. A full factorial design was employed to determine the optimum operating conditions for dairy wastewater treatment by electrocoagulation used separately or coupled with granular activated carbon (GAC). Current density, initial pH, and GAC mass were chosen as the controlling process parameters and examined at three levels. The results showed that EC reduced turbidity and COD from SDW to 98.75% and 78.09%, respectively, when pH = 4 and with current densities of 20.83-27.77 mA/cm². The EC/AD process enhanced turbidity reduction to 99.39% and COD removal to 87.12% when small masses of GAC (0.5 to 1.5 g) were used at the lowest applied current density level of 13.38 mA/cm². In comparison to classical electrocoagulation using aluminum electrodes in a batch system, coupling electrocoagulation to adsorption technique achieved faster removal of pollutants with lower operating costs. Operating costs of the EC/AD process for turbidity and COD removals were calculated as 0.360 €/m3 and 0.746 €/m³ vs. 0.494 €/m³ and 0.692 €/m³ for the EC process. Correlations with the experimental data for the EC process were R² = 95.78% for turbidity and R² = 96.22% for COD removal. For the coupled EC/AD they were R² = 96.61% for turbidity and R² = 95.48% for COD removal. [ABSTRACT FROM AUTHOR]

BACKGROUND: Due to the environmental problems caused by food processing wastewaters and their complex and expensive treatment methods, it becomes mandatory to seek a sound, sustainable and environmentally friendly solution such as constructed wetland (CW). This study aimed to investigate the potential of treating real dairy wastewater in CW. Six horizontal subsurface flow CW microcosms were set up using different conventional and cost‐effective supporting media, which were gravel, soil and sand. All the CWs were fueled continuously with real fresh dairy wastewater. Five of the six CW microcosms were planted with Canna indica. The remaining CW microcosm was kept unplanted and was considered as a control microcosm. RESULTS: The results revealed significant removal efficiencies of organic matter (as chemical oxygen demand) up to 89.92%, 97.6%, 95.8%, 97.2%, 97.3% and 98.2%, for CW1, CW2, CW3, CW4, CW5 and CW6, respectively. Also, high removal efficiencies of ammonium were observed in the range of 98.4–82.0%, whereas removal efficiencies of total suspended solids were in the range of 99.2–93.4%. CONCLUSION: The results demonstrated that the dominant mechanisms for organics and ammonium removal were biodegradation processes. These promising results confirmed the validity of using constructed wetland as a sustainable cost‐effective approach for dairy wastewater treatment. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study investigated the treatability of dairy industry wastewaters by using the Fenton process and membrane bioreactors. Firstly, the effects of the Fenton process on the reaction time, pH, Fe2+ and H2O2 concentrations on chemical oxygen demand (COD) and total organic carbon (TOC) removal were determined to evaluate the treatment of dairy industry wastewater. According to the results obtained, the optimum reaction time, pH, Fe2+ and H2O2 concentrations were found to be 60 min, pH 3, 1 g/L, 1.5 g/L, respectively, while the COD and TOC removal efficiencies were 87% and 75%. Secondly, biological treatability of wastewater in membrane bioreactors was investigated. The input water COD concentrations of 0.6–2 g/L, sludge age values of 3 h to 10 d and different hydraulic waiting processes were studied. Loading was made to the system at 5 kg COD/ m³d, and later, loading was increased up to 17 kg COD/m³d based on the input water COD values. After treatment with membrane bioreactors, the COD removal efficiency varied between 95%–98%. As the output water concentrations obtained as a result of the study satisfied the discharge limits, the applied biological treatment and advanced oxidation methods were completed successfully. [ABSTRACT FROM AUTHOR]

In this study, the optimization of polyhydroxyalkanoates (PHA) production using acidified dairy wastewater (DW) and organic food waste (OFW) as a substrate source was investigated. The study included (a) acclimation of activated sludge in two sequencing batch reactors operated under different operational conditions (feast-famine and anaerobic-aerobic-anoxic) and fed with domestic wastewater only and with volatile fatty acid (VFA) supplement, (b) acidification experiments designed for the initial substrate to inoculum (S/I) ratios of 1, 2.5, 5 and 10 g tCOD/g VSS (tCOD - total chemical oxygen demand and VSS - volatile suspended solids) using DW and OFW, (c) batch experiments for PHA production using each acidified substrate source. The maximum acidification yields were obtained at the S/I ratio of 10 as 51.7% and 46.6% for DW and OFW at 4th d. PHA contents of up to 67.3% and 4.5% of dry cell weight were obtained using VFA obtained from acidification of DW and OFW, respectively. Accordingly, the results showed that acidification of 1000 m3 of DW and one tone of the wet weight of OFW could produce 173 and 20.3 kg of polymer, respectively. This could be attributed to a significant profit when a large amount of DW and OFW is considered. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) are one of the sustainable technologies that can effectively treat wastewater with concomitant generation of electricity. The present study investigated the treatment of real dairy wastewater (RDW) using Shewanella algae (MTCC-10608) within a single chamber microbial fuel cell (SCMFC). The study was conducted in both batch and fed-batch modes with initial chemical oxygen demand (COD) of 4000 mg/L and 2000 mg/L, respectively, in 0.2 L working volume of RDW for 15 days. However, the fed-batch strategy involved subsequent feeding of dairy wastewater with 6000 mg/L and 8000 mg/L COD on the 5th and 10th day, respectively. This two-step feeding strategy resulted in a maximum open-circuit voltage of 666 mV at 286 h of incubation with a COD removal efficiency of 92.21% and a columbic efficiency of 27.45%. The kinetic studies predicted the saturation constant of 55.83 mg COD/L and current density of 143.3 mA/m2, which are similar to the findings from the experiments and polarization curve obtained. The maximum current density and power density from experiments were found to be 141 mA/m2 and 50 mW/m2 respectively. Thus, this study successfully indicates the utilization of dairy wastewater as a potential substrate for the sustainable power generation using Shewanella algae as a biocatalyst in the microbial fuel cell. • Process development to achieve stable voltage from dairy wastewater. • Fed batch kinetics and performance analysis of MFC. • Characteristics of polarization and power density curve. [ABSTRACT FROM AUTHOR]

The present work reports treatment of real dairy products wastewater by electrocoagulation- flotation (ECF). The process was performed in a batch stainless steel reactor equipped with aluminum electrodes. The model attributed to batch ECF process was optimized employing response surface methodology (RSM) via operating variables viz. pH, current intensity, and electrolysis time in view of chemical oxygen demand (COD), total kjeldahl nitrogen (TKN), total phosphorus (TP), and turbidity, as well as fat-oil-grease (FOG) removal from wastewater. Sludge settling characteristics, specific electric energy consumption (SEEC), and biodegradability of treated effluent were also analyzed. The p-values with low probability (<0.05), determination coefficient (R² = 0.61-0.97) and the non-significant lack of fit (p > 0.05) showed quadratic models with a good fit with experimental terms. The process was favored at pH, 8; current intensity, 3A; and electrolysis time, 45 min. Under optimized conditions, removal of COD, TKN, TP, and FOG were 66%, 73%, 98%, and 97%, respectively. The results further indicated an improved biodegradability of treated effluent in terms of BOD5/COD ratio (0.79 as compared to 0.41 in raw wastewater) under optimum conditions. Moreover, sludge volume index and SEEC were ~86 mL/g and 0.069 kWh/kg COD, respectively. The enhanced performance of this promising electrochemical process in the treatment of real dairy wastewater might be explained by a combination of direct coagulation/floatation of suspended organics/inorganics and indirect oxidation-reduction of dissolved chemicals by oxygen bubbles in the anode and hydrogen in the cathode, rendering it amenable to the final aerobic treatment. [ABSTRACT FROM AUTHOR]

The treatment of dairy wastewater in methanogenic reactors cause several problems due to their high lipid content. One strategy to overcome these problems is the use of commercial formulations. Here we studied the effect of adding a commercial formulation, designed to improve fat degradation, on both the microbial community composition and reactor performance. Samples from two full-scale Up-flow Anaerobic Sludge Blanket (UASB) reactors in parallel arrangement were analysed. The commercial product was added to one of the reactors while the other was used as control. The amendment increased significantly the fat removal but an accumulation of volatile fatty acids was detected. Nevertheless, no significant differences were observed in the total Chemical Oxygen Demand (COD) removal and biogas production between reactors. A significant change in the bacterial community was not detected by 16S rRNA gene Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis probably due to the limitation of the technique. A strong change in the composition of the phylum Firmicutes was detected with 16S rRNA gene amplicon sequencing; however, it didn't persist during the whole operation period. The relative abundance of minor Operational Taxonomic Units (OTUs) with sequences related to syntrophic bacteria increased with the amendment. Although a better hydrolytic capacity was obtained when adding the commercial product, the overall process did not improve and no increase in biogas production was detected. Alternative strategies could be applied to avoid the accumulation of intermediary products and improve biogas production as intermittent addition of the commercial product or batch operation of reactors. [ABSTRACT FROM AUTHOR]

A fed batch membraneless microbial electrolysis cell (MEC) was investigated for treating combined leachate and dairy wastewater at an applied voltage 0.8 V and hydraulic retention time (HRT) of 48 h. The COD (chemical oxygen demand) removal and energy recovery was tested by running several cycles of MEC with increasing ratios of leachate to dairy wastewater. With an increase in percentage of simulated leachate, MEC performance in terms of current generation, COD removal efficiency and hydrogen production showed a gradual decrease. A sudden drop in reactor performance was noticed when the concentration of leachate was increased from 14 to 16% corresponding to an increase in Organic Load Rate (OLR) from 23.89gCOD/m3/d to 24gCOD/m3/d. A continued operation of MEC at an OLR of 24gCOD/m3/d for ten continuous cycles resulted in COD removal efficiency of 73% and hydrogen production of 15 mL/L/d with current density of 10 A/m2 and a power density of 80 mW/cm2. • Single chambered membraneless MEC treated leachate at low voltage 0.8 V and HRT 48 h • The MEC was operated with different organic loading rate (i.e) 18.57 to 24 gCOD/L/d. • A maximum COD removal efficiency of 73% and power density of 80 mW/cm2 was recorded. • Operation at OLR 24 gCOD/L/d for ten consecutive cycles showed improved performance. [ABSTRACT FROM AUTHOR]

The dairy industry is considered as one of the most polluting industries due to the presence of a very high percentage of organic matter in the effluent. Advanced oxidation processes, including ultrasonic/persulfate, are efficient processes for wastewater treatment. Therefore, the aim of this study, experimental laboratory research, was to evaluate the efficiency of US/persulfate process for the treatment of real dairy wastewater. In this study, the effects of pH (3, 5, 7, 9 and 11), persulfate concentrations (50, 100, 250, 500 and 750 mg/L), contact time (10, 30, 45, 60 and 90 min) and intensity of US waves (35, 37 and 130 kHz) on the efficiency of process were investigated using chemical oxygen demand (COD) as a dependent variable. According to the results, the efficiency was increased by decreasing the pH value, increasing the concentration of persulfate to an optimal level, and increasing the contact time and ultrasound intensity. The highest efficiency was obtained as 74.5% for real dairy wastewater. The high efficiency in the US/persulfate process was obtained at pH 3, persulfate concentration of 500 mg/L, US intensity of US 130 kHz and contact time of 60 min. The results showed that the sono-activated persulfate process for COD degradation of dairy wastewater follows the pseudo-first-order kinetic. According to the results, it can be concluded that US/persulfate process is an effective method for the removal of organic matter from real dairy wastewater. [ABSTRACT FROM AUTHOR]

Treated wastewater reuse has been considered recently as one of the successful management strategies to overcome water shortage in many countries suffering from water scarcity. The non-readily biodegradable and recalcitrant pollutants in wastewater cannot be destructed by conventional treatment methods. This paper deals with the electrochemical treatment of dairy wastewater using a promising non-conventional boron doped diamond anode. During the electrochemical process, different operating parameters were investigated, such as electrolysis time, current density, supporting electrolyte, chemical oxygen demand (COD), turbidity as well as absorbance/color. The experimental work revealed that electrochemical oxidation carried out with no added electrolyte has significantly reduced the COD, turbidity and color (absorbance) by 72%, 76% and 78%, respectively. Results also showed that raising the current density from 5.1 to 7.7 mA/cm² has boosted COD, and color removal to 82.5% and 83%, respectively. However, the current density did not show any significant effect on the turbidity. Interestingly, it was observed that adding Na2SO4 and FeCl3 as supporting electrolytes brought the COD removal to 91% and 97% respectively. Likewise, turbidity and color removal have been enhanced by the addition of the same supporting electrolytes. [ABSTRACT FROM AUTHOR]

Microbial fuel cells are innovative technologies that can efficiently remove chemical oxygen demand and biochemical oxygen demand, while simultaneously generating electricity, with a minimal environmental footprint. High efficiencies have recently been achieved for the treatment of low-strength wastewater. However, in treatment of a real high-strength wastewater, such as dairy effluent, the efficiency decreases drastically due to operational instability associated with environmental fluctuations, difficulty of maintaining the run for long periods, and fouling. In order to overcome these issues, a new initialization method was developed, with a start-up phase employing an inoculum composed of a consortium of fermenting and metal-reducing bacteria, followed by acclimation and treatment phases. The protocol employed enabled removal of 90% of total biochemical oxygen demand, 62% of total chemical oxygen demand, 72% of total Kjeldahl nitrogen, 71% of sodium, and 65% of ultraviolet absorbing substances from dairy wastewater. Furthermore, the microbial fuel cell produced maximum power densities of 1.45 W/m3 in the acclimation phase and 1.32 W/m3 in the treatment phase. The findings demonstrated that microbial fuel cells powered by real high-strength dairy wastewater can achieve high efficiencies. [ABSTRACT FROM AUTHOR]

In this paper, dairy wastewater treatment was investigated by Fenton and electro-Fenton (EF) processes in respect of removal efficiencies of chemical oxygen demand (COD), orthophosphate, suspended solid (SS), and color. The response surface methodology (RSM) approach using Box–Behnken design was carried out to develop mathematical model and to optimize process parameters. Experimental data were analyzed by the analysis of variance (ANOVA) to identify the interaction mechanism between the process variables and the dependent variables. According to ANOVA results of Fenton process, COD removal increased with an increase in H2O2/COD ratio and reaction time but decreased with increased H2O2/Fe2+ ratio and initial pH. Opposing to that, in the EF process, COD removal increased with an increase in H2O2/Fe2+ ratio and reaction time but decreased with an increase in H2O2/COD ratio and initial pH. The COD removal efficiencies were 65.5 and 72% under the optimum conditions for Fenton (H2O2/COD ratio 1.9, H2O2/Fe2+ ratio 5, pH 4 and reaction time 10 min) and electro-Fenton (H2O2/COD ratio 2, current density 32 mA/cm2, pH 2.4 and reaction time 45 min) processes, respectively. No significant removal differences for orthophosphate, SS and color were determined between the two processes because the removal efficiencies were over the 88% for each process configuration where P value was greater than 5.6 * 10−5 with 99% confidence level and greater than 1.7 * 10−3 with 95% confidence level for all responses for Fenton and EF processes, respectively). [ABSTRACT FROM AUTHOR]

Background and Aim: Among the industries the dairy of the industry to recognize one of the most polluting Sources due to the presence of a high percentage of organic matter in the effluent. Recently, advanced oxidation processes, including Ultrasonic-persulfate with production of free radical such as sulfate and hydroxyl radicals is the efficient processes in wastewater treatment. Therefore, the aim of this study was evaluation efficiency of US-persulfate processes in treatment synthetic dairy wastewater. Materials and Methods: This research was an experimental-laboratory study. In this study, dry milk was used to make synthetic dairy wastewater and effect of pH (3, 5, 7, 9, 11), persulfate concentrations (50, 100, 250, 500, 750 mg/L), contact time (10, 30, 45, 60, 90 min) and intensity of waves US (35, 37, 130 kHz) was investigated on efficiency and the process efficiency was measured by calculating the residual chemical oxygen demand using spectrophotometrically at a wavelength of 600 nm. Results: According to the results, the efficiency increased by decreasing the pH value, increasing the concentration of hydrogen peroxide to an optimal level and increasing the contact time and ultrasound intensity and also was found that the efficiency of US-persulfate process at pH 3, concentration of persulfate500 mg/L, intensity of US 130 kHz and contact time 60 min had the highest efficiency that the amount of this efficiency was 74/53% and 61/1% for synthetic dairy wastewater and actual dairy sewerage respectively. Conclusion: According to the results, the acoustic-activated peroxylate process can be a good and highperformance method for removing organic matter from dairy wastewater. [ABSTRACT FROM AUTHOR]

A potential microalgal strain was isolated from dairy industrial effluent contaminated water and genetically identified as a close relative of Ascochloris sp. The current study demonstrates growth, biomass and lipid productivity of Ascochloris sp. ADW007 and simultaneous bioremediation of raw dairy waste water (RDW). Indoor microalgal cultivation studies were conducted in controlled conditions of light and temperature, while outdoor pilot-scale experiments were performed in errant conditions using semi-cylindrical barrel shaped open troughs. The rate of biomass productivity of ADW007 was improved with RDW as growth nutrient in indoor bench-scale (0.102 ± 0.003 g/L/d) and outdoor pilot-scale cultivations (0.207 ± 0.003 g/L/d) when compared with the algal growth in synthetic BG 11 medium (0.086 ± 0.004 g/L/d) and TAP medium (0.099 ± 0.003 g/L/d), respectively. Similarly, in outdoor conditions, the lipid content reached maximum to 34.98 ± 0.21% with volumetric and areal lipid productivities of 0.072 ± 0.001 g/L/d and 9.63 ± 0.08 g/m2/d, respectively. With this, the estimated annual algal oil production is nearly 20,495 ± 1953 gallons/acre/yr, if cultivated throughout the year. C18:0/C18:1 were the predominant fatty acids in lipid which indicates a great potential of ADW007 for biodiesel production and simultaneous bioremediation processes using RDW. Post-harvesting process includes hollow fiber filtration followed by activated carbon treatment and resulted in 95.1, 79.7 and 98.1% reduction in chemical oxygen demand, nitrate and total phosphate, respectively. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the efficiency of horizontal subsurface flow constructed wetlands (HSFCWs) planted with Typha domingensis and Phragmites australis in the final treatment of dairy wastewater. Ten microcosms-scale reactors simulating HSFCWs were arranged outdoors under a semi-transparent plastic roof. Five replicates were planted with T. domingensis and five with P. australis. In both cases, light expanded clay aggregate (LECA) 10/20 was used as a substrate. Real effluent with previous treatment was used. In order to evaluate contaminant removal efficiencies in each reactor, pH, electrical conductivity, suspended solids, ammonium, nitrate, nitrite, total phosphorus, and chemical oxygen demand (COD) were analyzed before and after treatment. HSFCWs planted with T. domingensis and P. australis were efficient for the final treatment of dairy wastewater. Removal efficiencies obtained in microcosms planted with both macrophytes were over 96% for ammonium and nitrite. Nitrate removal efficiency was 39%. COD decreased along the experiment near 75% for both treatments. High removal percentages for suspended solids (78.4-81.1%) were also achieved. However, systems planted with T. domingensis were significantly more efficient for total phosphorus removal (88.5%) than those planted with P. australis (71.6%). [ABSTRACT FROM AUTHOR]

Dual-chambered microbial fuel cells were tested in batch mode with three different electrodes: graphite rod, graphite felt, and carbon cloth as anodes and cathodes. Dairy wastewater, after sedimentation (initial chemical oxygen demand of 1,357 mg/L), was the feed for microbial fuel cell. The inoculum for the experiments conducted was a mixed culture of anaerobic microorganisms sourced from dairy wastewater. This study aimed to evaluate the performance of three electrodes in microbial fuel cell on the basis of their power generation and their wastewater treatment efficiency (chemical oxygen demand, total organic carbon content, turbidity), respectively. Carbon cloth produced the maximum open circuit voltage and power density (0.847 V and 1.36 W/m²) followed by graphite felt (0.812 V and 1.22 W/m²) and graphite rod (0.658 V and 0.78 W/m²). From the polarization studies, it was found that external resistance of 100 Ω produced the maximum power density for all the three electrodes. Electron transfer ability of the electrodes in dairy wastewater was measured by cyclic voltammetry. Biofilm growth on the surface of the anode was visualized by scanning electron microscopy. Chemical oxygen demand removal efficiency was found to be more in microbial fuel cell with carbon cloths and was estimated to be 91.3%. There was a significant reduction of total organic carbon content and turbidity in wastewater by the deployment of the three electrodes. Even though the power generated through these microbial fuel cells is low, efficiency in water treatment was found to be high. Thus, microbial fuel cells can be used in dairy industries to treat wastewater and simultaneously generate power effectively. [ABSTRACT FROM AUTHOR]

The aim of this study was to consider the efficiency of the electro‐Fenton process for organic compound reduction in an industrial dairy effluent. Experiments were conducted to evaluate the effect of several parameters, such as reaction time, pH, H2O2/Fe2+ molar ratio and volume fraction of H2O2 to dairy wastewater (mL/L), on the process performance. The Taguchi technique was applied to investigate the optimum operating conditions. The optimum chemical oxygen demand removal (93.24%) was experimentally obtained at a pH value of 7.58, reaction time of 87.13, current density of 58.5, H2O2/Fe2+ molar ratio of 3.62 and volume fraction of H2O2 to dairy wastewater of 1.39 mL/L. [ABSTRACT FROM AUTHOR]

Among dairy effluents, bactofugate (B) and decreaming racking water (D) were identified as the most polluting due to their organic load content expressed in the chemical oxygen demand (156-240 g·L−1). Joining the plant wastewater, such effluents contribute to the increase of the polluting load of the wastewater treatment plant input which disturbs the treatment performance. This work proposes an upstream segregation of those dairy effluents for combined physical-chemical and biological treatment. An experimental design was proposed to investigate initial pH, applied temperature and exposure time factor effects on the thermal coagulation process. The fermentation of the resulted supernatants using Lactobacillus lactis ssp. lactis was performed. The optimized thermal coagulation pretreatment was obtained at (pH; T(°C); t(min)): 6, 60 °C and 5 min, with both (B) and (D) effluents. Resulted clarified whey sugar, protein and fat contents were assessed. The physical-chemical treatment resulted in considerable organic matter removal: 45% for (B) samples and 31% for (D) samples of proteins content and almost the total fat content. However, there is no considerable effect on the sugar content reduction, which remains responsible for the major fraction of the whey residual chemical oxygen demand (COD). Clarified whey fermentation using Lactococcus lactis ssp. lactis strain induced important sugar consumption rates. Therefore, important sugar consumption rates were recorded and the COD removal efficiency was improved. The recorded global COD removal efficiency was of about 93%. The proposed combined physical-chemical and biological processes for dairy effluents pretreatment allowed not only to reduce the effluents polluting load, but also to valorize wheys by producing valuable components. [ABSTRACT FROM AUTHOR]

The aim of this study was to determinate seasonal changes in industrial wastewater treatment effectiveness. Studies were carried out in mechanical-biological wastewater treatment plant in Bystre near Giżycko to which inflows mixture of domestic and dairy wastewater. Laboratory studies were carried out by Water and Wastewater Company in Giżycko. For statistical analysis results form years 2014 and 2015 were considered. The scope of statistical analysis includes basic statistical measures including arithmetic mean, median, minimum, maximum and standard deviation. Changes in seasonal treatment effectiveness were shown by Fisher-Snedecore LSD test. Seasonal changes were observed for BOD, COD and total nitrogen removal effectiveness. Total phosphorus was not subjected to that kind of changes. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the potential of utilizing Lactobacillus delbrueckii spp. bulgaricus in order to improve the characteristics of dairy wastewater and produce biomethane. Nuclear magnetic resonance was utilized to assess the metabolites present in the unprocessed wastewater. It was determined that wastewater is a good source of important bio-refinery relevant compounds and therefore wastewater has a potential to be utilized during fermentation as nutrients source. Upon wastewater fermentation, the chemical oxygen demand and biological oxygen demand significantly decreased (respectively 97.0 and 97.8%). Protocols were tested for one- and two-stage fermentation. During the one-stage fermentation, lactic acid bacteria were not added to the wastewater. During the two-stage fermentation, acetogenesis and methanogenesis occurred separately with the addition of L. delbdueckii during the acetogenesis stage. The highest yield of methane was obtained from wastewater upon two-stage fermentation (76% two-stages compared to 38% one-stage). Therefore, L. delbrueckii have the potential to be utilized to ferment dairy WWs and produce methane. Such treatment of wastewater not only produces methane, but also decreases the polluting effect of the waste streams, by reducing the chemical oxygen demand and biological oxygen demand to 0.199 and 0.031 g/l, respectively. [ABSTRACT FROM AUTHOR]

In this study, the experimental design methodology was applied for modeling and optimizing the critical operating parameters on photocatalytic degradation of chemical oxygen demand (COD) in dairy wastewater using CuO nanoparticles as photocatalyst in a photoreactor. Also, central composite design and response surface methodology (RSM) have been used to design the experiments, do statistical analysis, and to determine the optimum condition. The effects of four independent variables, including pH (3, 7, and 11), CuO nanoparticles dose (0.01, 0.03, and 0.05 g), reaction time (10, 30, and 60 min), and ultraviolet (UV) light intensity (8, 15, and 30 W) were investigated. The significance and adequacy of the model were analyzed using analysis of variance (ANOVA). Second-order quadratic model was built to predict the responses. The ANOVA of the COD removal efficiency from dairy wastewater by UV/CuO showed that the regression model is significant (p < 0.001). In optimum conditions of the photocatalytic degradation (pH = 7.2, CuO dose = 0.05 g, time = 60 min, and UV radiation = 30 W), COD removal efficiency equal 99.99% was achieved. The regression analysis with R2 value of 0.9743 and Adj. R2 value of 0.9697 showed a good correlation between the experimental and the predictive values. It was found that all factors considered have an important and significant influence on the degradation rate of the COD. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dairy wastewater was treated with combined AD and microalgal cultivation. • COD, TN and TP were removed during cultivation of a bacterial-algal consortium. • Highest nutrient removal & biochemicals production were obtained using 25% wastewater. • Co-digestion with 25% resulting algal biomass enhanced biomethane production. A sequential anaerobic digestion and phycoremediation process was employed to recover nutrients and remove pollutants from dairy wastewater (DW), while simultaneously producing biomethane and biochemicals. Anaerobic digestion of 100% DW achieved a methane content and production rate of 53.7% and 0.17 L/L/d, respectively. This was accompanied by the removal of 65.5% chemical oxygen demand (COD), 86% total solid (TS), and 92.8% volatile fatty acids (VFAs). The anaerobic digestate was then used to grow Chlorella sorokiniana SU-1. Using 25% diluted digestate as the medium, SU-1 could reach 4.64 g/L biomass concentration, with total nitrogen (TN), total phosphorus (TP) and COD removal efficiencies of 77.6%, 87.1% and 70.4%, respectively. The obtained microalgal biomass (contained 38.5% carbohydrates, 24.9% proteins, 8.8% lipids) was used to co-digest with DW, resulting in good methane production performance. Co-digestion with 25% (w/v) algal biomass obtained a higher CH 4 content (65.2%) and production rate (0.16 L/L/d) than other ratios. [ABSTRACT FROM AUTHOR]

The common means of wastewater pre-treatment is impractical in large-scale wastewater treatment plants (WWTP). There is still a lack of suitable microalgae to treat raw dairy wastewater (DWW) with high organic matter concentration. For screening more diverse microalgae to treat raw DWW, the growth characteristics and metabolite production of ten algal strains cultured in undiluted DWW were studied in this paper, among which three were able to tolerate excessive chemical oxygen demand (COD) concentration and yielded high biomass concentration. Under the condition of 25 ± 1 °C and 55 μmol/m2/s, the most suitable strain were Scenedesmus SDEC-13, Chlorella pyrenoidosa SDEC-35, and Chlorella vulgaris SDEC-34, all of which had biomass concentrations above 1.2 g/L and protein contents above 45%. Based on the feasibility of cultivating microalgae with raw DWW, an alternative alga-based WWTP strategy was provided for the first time. The most important modification was the construction of the photobioreactor (PBR) to replace hydrolytic upflow sludge bed (HUSB) reactor and remove anaerobic-aerobic (AO) pond. The dairy WWTP with a PBR unit (1.68 × 104 m3) will yield a biomass production of 1.44 × 106 kg/year while capturing 2.59 × 106 kg CO 2 /year. Through carbon comparison and economic analysis, we believe that the use of microalgal PBRs for the treatment of wastewater from dairy plants presents a cost-effective and environmentally friendly alternative for the future. And future research should focus on pilot scale photobioreactor in the natural environment and large-scale treatment of dairy wastewater. [Display omitted] • Three algal species tolerated high COD concentration and achieved excellent biomass. • Chlorella pyrenoidosa SDEC-35 obtained 50.2% protein content in dairy wastewater. • A PBR based on mixotrophic algae is a great substitute for HUSB and AO pond in WWTP. • A WWTP with an algal bioreactor unit (1.68 × 104 m3) will capture 2.59 × 106 kg CO 2 /year. [ABSTRACT FROM AUTHOR]

In this study, the potential of MEUF process has been analyzed to treat a real dairy wastewater. For this purpose, linear alkylbenzene sulfonate (LAS) and Triton X-100 (TX-100) have been used as anionic and nonionic surfactants, respectively. The ranges of 2–3.5 bars and 0–4 mM are selected for transmembrane pressure (TMP) and surfactants concentration, respectively, to investigate their effects on the permeate flux as a function of operating time. Moreover, it is revealed experimentally that rejection of pollution indices including chemical oxygen demand (COD) and total dissolved solid (TDS) is affected by TMP and feed surfactant concentration, while turbidity is remained relatively unchanged. According to the experimental results analysis, the increase of feed surfactant concentration has negative and positive effects on the permeate flux and rejection efficiency, respectively. TMP enhancement also leads to the higher flux values but it does not necessarily improve the rejection. Furthermore, the effectiveness of anionic surfactant in pollution indices elimination is more than the nonionic one. In the treatment combination assessed for the factors, the best rejection values of COD, TDS, and turbidity using LAS surfactant with polyacrylonitrile (PAN-350) 20-kDa poly(ethylene glycol) membrane are almost 93, 52, and 99.9%, respectively. [ABSTRACT FROM AUTHOR]

Based on its large water consumption, dairy industry is considered as one among the most polluting food industries. The present work is related to investigations about water management practices in one Tunisian dairy plant where two effluents’ generators were identified as the most polluting following their COD assessment. The first was the generated water from DECREAMING (D) machines washings with COD value of 112 g L−1, and the second source is BACTOFUGATE (B) with COD value of 196 g L−1. Thermal coagulation was performed for (D) and (B) samples leading to media clear phase separation. After decantation, recuperated supernatants were filtrated. The recorded COD removal amount exceeded 90% for both samples filtrates. Additional biological treatment was performed with mediums based on the obtained filtrates. IsolatedCandidastrains,Lactobacillusand baker’s yeast strains were inoculated in batch process fermentation. Different biological treatment effects were evaluated using musts COD assessment at the end of fermentation after biomass removal. The reduction in organic load was important with the appropriate inoculated strains. [ABSTRACT FROM AUTHOR]

Dairy industries and milk processing plants normally discharge their wastes directly to the close surroundings, generating environmental nuisances. Consequently, dairy wastewater deserves special attention since its levels of potential contaminants typically exceed those levels considered hazardous for domestic wastewater. At present study, performance of conventional chemical coagulation using poly aluminum chloride as an inorganic pre-polymerized coagulant (at various pH and coagulant dosages) and adsorption process by modified dried activated sludge (with ZnCl2) for treatment of real dairy wastewater was investigated. Maximum removal efficiency of pollutants (BOD5and chemical oxygen demand (COD)) by chemical coagulation process was achieved at initial pH 8 and coagulant dose 100 mg/L in 60 min. In addition, optimum conditions for adsorption process were found to be: initial pH 6, adsorbent dose of 7 g/L, and contact time 90 min. The biosorption equilibrium data were fitted by Freundlich isotherm. Furthermore, according to the thermodynamic properties, ΔG°, ΔH°, and ΔS°, adsorption of COD onto modified dried activated sludge was spontaneous, endothermic, and feasible in the temperature range of 298–318 K. [ABSTRACT FROM PUBLISHER]

This study evaluated the potential of the biosurfactant-producing yeastCandida bombicolain treating wastewater containing fats and oils from a dairy industry in a laboratory scale bioreactor. The dairy wastewater contains high chemical oxygen demand (COD) (2,480 mg/L) and fats and oils (407 mg/L) and was supplemented with sugarcane molasses (1% w/v) and yeast extract (0.1% w/v) to support the growing yeast in batch, fed-batch, and continuous operations. The yeast was able to remove fats and oils completely (more than 95% COD removal) under batch and continuous operation. The study suggested that wastewater containing high fats and oils can be efficiently treated usingC. bombicola. [ABSTRACT FROM PUBLISHER]

An intermittent sand filter (ISF) is a simple and cost-effective treatment method that may be adopted on farms to treat dairy wastewater (DWW). However, the use of ISFs has been limited due to the large area required for treatment, and the risk of filter clogging and phosphorus (P) breakthrough, which decrease the operational lifetime. To overcome these limitations, this study uses a novel, pilot-scale coagulation-sedimentation process prior to loading ISFs with DWW. The performance and operational lifetime of this new hybrid coagulation-ISF system was compared to a conventional ISF system in a replicated outdoor pilot-scale experiment over a 43-wk study duration (covering an entire milking season on a farm in Ireland). The hybrid system was able to operate effectively at a higher hydraulic loading rate than a conventional ISF system. The effluent quality from the conventional ISF deteriorated over the timeframe of the study until clogging occurred, while the hybrid system continued to perform effectively without any evidence of clogging or P breakthrough. The hybrid system obtained removal efficiencies ≥99% for all measured water quality parameters (chemical oxygen demand, total suspended solids, total P, ammonium and turbidity), and complied with EU directives concerning urban wastewater treatment. Overall, the hybrid coagulation-ISF is a promising technology that requires a small area (75% reduction in footprint in comparison to a conventional ISF) and minimal operator input, and produces high effluent quality. [Display omitted] • Performance of novel hybrid coagulation-ISF was compared to conventional ISF. • The coagulation-ISF system required only 25% of the conventional ISF size. • The coagulation-ISF system did not experience any clogging or P breakthrough. • The conventional ISF encountered both clogging and P breakthrough. • The coagulation-ISF produced better effluent quality than conventional ISF. [ABSTRACT FROM AUTHOR]

Membrane fouling is still a critical issue which limits the application of industrial membrane utilizations. Membrane processes operating at a high shear rate are frequently used to control flux decline by reducing the deposition of particles on the membrane surface. In this work, ultrafiltration (UF) of a dairy model and industrial wastewaters was investigated. Membrane module vibration and no-vibration mode were compared by a laboratory mode vibratory shear enhanced processing device during membrane filtration with the same operational parameters. Membrane fluxes, rejections, and energy consumption were measured and calculated for comparison of the vibration effectiveness. Turbidity, chemical oxygen demand, and total organic carbon were measured. The UF experiments were carried out with constant parameters at a temperature of 50°C and recirculation flow rate of 910 L h−1at 0.8 MPa. Furthermore, to understand the fouling mechanisms in depth, contact angles of the clean, prewetted, and fouled membrane were measured to determine the wettability for characterization of the membrane. [ABSTRACT FROM PUBLISHER]

The present study is an attempt to anaerobically co-digest excess sludge from aerobic facility of dairy wastewater treatment plant in a hybrid upflow anaerobic sludge blanket reactor. The sludge was made amenable for anaerobic degradation using ozone and chemical pretreatment. The efficiency of the treatment at optimized condition (pH 11 and ozone dosage 0.06 gO3/g suspended solids) showed 68 and 61% of chemical oxygen demand solubilization and suspended solids reduction, respectively. Further, anaerobic co-digestion of pretreated sludge was evaluated in two lab-scale hybrid upflow anaerobic sludge blanket reactors, namely experimental (ER) and control reactors (CR), with 5.6 L working volume for a period of 310 d. Treatment of dairy wastewater at the highest applied organic loading rate of 16.78 kg chemical oxygen demand/m3 d, the biogas production increased in ER reactor (18.8 L/d) with the introduction of pretreated sludge than in CR reactor (17.9 L/d). The performance of ER reactor is not influenced by anaerobic co digestion of pretreated sludge, because no statistical difference between soluble chemical oxygen demand removal efficiencies of ER and CR reactors. [ABSTRACT FROM PUBLISHER]

The micralgae-based biofuel obtained from dairy wastewater (DWW) is considered a promising source of energy. However, this process consumes water due to the concentration of wastewater being normally too high for some micoralgae cultivation, and dilution is always needed. In this work, the cultivation of microalgae has been examined in non-recirculated water (NR) and recirculated water systems (R). The growth of Chlorella zofingiensis and the nutrient removal of DWW have been recorded. The comparison indicates the R had a little more advantage in biomass and lipid output (1.55, 0.22 g, respectively) than the NR (1.51, 0.20 g, respectively). However, the total chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and total phosphorus (TP) removals of the R were lower than those of the NR system during the culture. The highest removal of total COD, TKN, and TP were 85.05%, 93.64%, and 98.45%, respectively. Furthermore, no significant difference has been observed in the higher heating value and lipid content of the biomass of the R and NR. The results show the R can save 30% of the total water input during the culture. All above results indicate the R system has great potential in industry. [ABSTRACT FROM AUTHOR]

To overcome the shortcomings of direct anaerobic digestion of the dairy waste effluent, an enzymatic pre-treatment have been employed to significantly overcome the sludge problems and other drawbacks. This work describes the application of Lipase Z to perform the enzymatic pre-hydrolysis of a synthetic dairy wastewater containing around 2,000 mg/mL of fat content. Different process parameters like effect of enzyme loading, temperature, different concentration of fats and different concentrations of NaCl were optimized for maximum conversion of fat. The maximum hydrolysis of around 75% is achieved at 0.2% w/v enzyme loading, 30°C and 100mM NaCl concentration for 2,000 mg/mL fats content. It was contemplated that the enzymatic pre-hydrolysis prior to the anaerobic digestion reduced the reaction time required for anaerobic degradation, improved biogas formation and appreciative chemical oxygen demand removal. [ABSTRACT FROM AUTHOR]