Search

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]

Abstract\nNovelty statementCoal mine drainage (CMD) is an environmental threat due to its high volume, low pH, presence of toxic metals, and absence of biodegradable organics. The present study aims to treat CMD in a horizontal sub-surface flow constructed wetland (CW) using dairy wastewater as an organic source. CW was planted with Typha angustifolia. Characteristics of synthetic CMD were (except pH, all unit mg/L) pH 1.9; Fe: 100, SO42−: 1,000, Mn: 6, Zn: 5, Co: 1, Ni: 1, and Cr: 1. CMD was mixed with synthetic dairy wastewater (pH: 5.05, COD: 2,700 mg/L, BOD: 1,600 mg/L) in the ratio of 3:1. Alkalinity of 120–190 mg/L CaCO3 was generated and effluent pH improved from 2.2 to 6.6. Metals precipitated as metal sulfide or hydroxide. Sulfate removal was hindered due to the synergistic toxicity of several metals. Except for Mn, all other effluent parameters were within the discharge limit for disposal in inland surface water.There is limited information available on the advantages of using organic rich wastewater as a substrate for treatment of low carbon coal mine drainage (CMD). Coal mine drainage was mixed with dairy wastewater and treated in horizontal flow constructed wetland. Organic removal, metal removal, sulfate removal, and pH improvement of mixed wastewater are investigated in the present study. [ABSTRACT FROM AUTHOR]

Although two-stage anaerobic digestion (TSAD) is not a novel process, information of the process stability, microbial community and effective operating conditions is limited and often contradictory. In this work, the influence of different carrier materials (polyurethane foam, carbon felt, Raschig rings and a combination of carbon felt and Raschig rings) on the performance of the thermophilic TSAD of dairy wastewater was studied. The organic loading rate (OLR) in the acidogenic reactor (RH) was gradually increased from 13.74 to 32.56 g COD/(L d), and from 0.64 to 11.46 g COD/(L d) in the methanogenic reactors by correspondingly reducing the hydraulic retention time (HRT). The highest hydrogen production rate of 1280.3 mL/(L·d) and hydrogen yield of 93.2 mL/g COD were achieved at OLR of 13.74 g COD/(L·d), but hydrogen production stopped at higher OLR. The main soluble metabolites in RH were butyrate and lactate, and the microbial community was dominated by Streptococcus , Thermoanaerobacterium , Veillonellales-Selenomonadales and Pseudomonas. The highest methane production rate (2674 mL/(L·d) at HRT of 0.5 days) was observed in the reactor with polyurethane foam, while the highest methane yield (305.5 mL/g COD at HRT of 1.5 days) was obtained in a reactor containing carbon felt. Spirochaetaceae , Desulfomicrobium , Anaerolineaceae , Candidatus Caldatribacterium and Cloacimonadaceae W5 were linked to these materials and explained the highest methanogenic performance. [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]

The dairy industry generates substantial wastewater, which is commonly treated using integrated anaerobic hydrolysis and aerated biofilm reactors. However, the bacterial composition and functional differences within the generated floccules remain unclear. In this study, we employed 16S rRNA and metagenomic sequencing to compare bacterial communities and enzyme gene profiles between suspended floccules from the hydrolysis ponds and the aeration ponds. Results revealed that the bacterial phyla Firmicutes, Proteobacteria, and Bacteroidetes dominated the wastewater treatment system and the relative abundance of these bacterial phyla varied in each pond. Additionally, the aeration ponds exhibited higher bacterial operational taxonomic units and enzyme gene abundance. Network analysis demonstrated a more complex bacterial network structure in the hydrolysis ponds compared to the aeration ponds. Furthermore, enzyme gene abundance revealed higher metabolic enzyme genes in the hydrolysis ponds, while signal transduction enzyme genes were more abundant in the aeration ponds. Notably, the top 10 bacterial genera, primarily Hydromonas in the hydrolysis ponds and Ferruginibacter in the aeration ponds, exhibited distinct contributions to signal transduction enzyme genes. Hydromonas dominated the metabolic enzyme genes in both ponds. These findings provide crucial insights for optimizing dairy wastewater treatment technologies. [ABSTRACT FROM AUTHOR]

Brewery (BW) and dairy (DW) wastewater are two types of agro-industrial wastewater that are generated in large amounts and, therefore, should be treated effectively and in an environmentally beneficial manner. Both these wastewater types are characterized by a high COD, BOD5, and nutrient content, and conventional wastewater treatment methods such as an activated sludge process may prove to be inefficient due to the possibility of foaming, large biomass production, low activity at low temperatures, and risk of overloading the reactor with a load of organic pollutants. In the context of the described difficulties, anaerobic processes seem to be the best alternative. An interesting research area is the co-digestion of these wastewaters. However, this research direction, so far, has not been frequently reported. Given the gap in the current knowledge, this literature review aims to assess the possibility of BW and DW digestion in anaerobic reactors and provide up-to-date data on the post-treatment methods of effluent generated after the anaerobic digestion process. Despite numerous advantages, anaerobic treatment often requires post-effluent treatment to complete the treatment cycle. [ABSTRACT FROM AUTHOR]

Dissolved air flotation (DAF) waste, a byproduct with high lipid content separated from dairy wastewater, is disposed of by land spreading and causing environmental pollution. To develop a sustainable treatment for DAF waste, this study investigated the effects of food to inoculum (F/I) ratio and ultrasound pre-treatment on the anaerobic digestion of DAF waste. The biochemical methane potential (BMP) of tested DAF waste ranged from 436–566 mL CH 4 /g VS fed. Increasing the F/I ratio (>1.0) inhibited methane production due to long chain fatty acids (LCFA) accumulation, which high concentrations of oleate inhibited methanogenesis and delayed palmitate degradation. Ultrasound pre-treatment with 30 min pulse (10 s on/ 10 s off) and 15 min continuous operations increased soluble chemical oxygen demand in DAF waste by 82% and 52%, respectively. Moreover, continuous sonication removed 38% of LCFA due to the implosion of cavitation bubbles. The BMP of DAF waste increased by 36% after sonication with F/I ratio 3.0. However, the lag time of methane production was prolonged after sonication due to the fast release of LCFA to the bulk solution. By implementing ultrasound pre-treatment and optimizing the F/I ratio, the energy potential of DAF waste can be harnessed, leading to more sustainable practices in dairy production. [ABSTRACT FROM AUTHOR]

Oil and grease are one of the most important pollutants in dairy industry wastewater. Flotation is a well-known and reliable method used in dairy industry wastewater to remove oil-grease, and it can remove oil & grease as well as suspended solids and organic materials. Dissolved Air Flotation (DAF), is a flotation technique and is classified as (traditional) Classical DAF (CP-DAF) and new generation - microbubble pump DAF (MB-DAF) systems considering the air bubble generation method. The major difference between the two systems is the microbubble size. Generally, the bubble size of 50-120 microns in KP-DAF systems decreases to 20-50 microns in MB-DAF systems. Besides that, the classical DAF system has a more complex structure than the new generation DAF systems. It consists of more equipment, thus maintenance requirement is high and causes troubles more often. This situation requires constant effort and attention during the operation. In this study, oil & grease and suspended solid (SS) removal efficiency was evaluated by using pilot scale experimental DAF system. The impact of inflow rate, pump type, and the pressure was investigated. Pilot-plant was employed in the dairy factory and operated by real wastewater. The results shown that CP-DAF System has yielded lower oil & grease and suspended solid removal efficiency than MB-DAF systems. It has been determined that the optimum working pressure is 4 bar in both systems, and the highest performance was obtained at 1 m³/h. For CP-DAF system, oil & grease and SS removals were obtained as 61% and 54%, respectively. However, 70% and 63% removals for oil & grease and SS were performed for MB-DAF system. Accordingly, it has been obtained that the MB-DAF System operating at 1 m³/h and 4 bar, has approximately 10% higher performance in oil-grease and SS removal than the CP-DAF System. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) of synthetic and real dairy wastewater was the focus of the study for parametric estimation of kinetic models with examining biochemical methane potential (BMP), treatment efficiency, and energy effectiveness of the process. The effect of substrate-to-inoculum ratio (S/I) on batch reactor performance was investigated under mesophilic (35°C±2°C) conditions for 30 days. Based on the volatile solid (VS) content, three different S/I ratios were considered: 1∶1 (Treatment A), 1∶3 (Treatment B), and 1∶6 (Treatment C). Organic matter removal in VS units was as high as 56%. Almost 90% of the biogas was produced during the first 14 days of digestion, with a biogas yield of 337±23 , 305±48 , and 356±37 mL/g VS for Treatments A, B, and C, respectively. Methane content increased with increasing inoculum amounts in the medium. The experimental cumulative methane yield from both synthetic and real dairy wastewater was contoured for parametric estimation in four different kinetic models, namely first-order (FO), modified Gompertz equation (GE), modified logistic (LM), and modified transference (TM) models. The modified TM model was the best fit for overall treatment, with predicted methane production potential of 279.8 and 235.9 mL/g VS compared with the experimental value of 272 and 229 mL/g VS in treatment C for synthetic and real dairy wastewater, respectively. Preliminary studies showed the potential of energy generation, which may supplement 32% of the overall energy use. These results demonstrate the importance of understanding the effect of the S/I ratio involved in AD to treat synthetic and real dairy wastewater. [ABSTRACT FROM AUTHOR]

Biopesticides offer a sustainable and efficient alternative to synthetic pesticides, providing a safer and more eco-friendly solution to pest management. The present work proposes an innovative approach that integrates crop protection and wastewater treatment using thermophilic microalgal strain Chlorella thermophila (CT) cultivated in nutrient-rich dairy wastewater as a growth medium. The microalgae was cultivated mixotrophically and was able to reduce both organic carbon as well as nutrient load of the dairy wastewater efficiently. The integrated circular biorefinery approach combines biomass cultivation, extraction of biopesticide compounds, and conversion to biocrude. The antimicrobial activity of the biopesticidal extracts against Xanthomonas oryzae and Pantoea agglomerans, the causative agent of bacterial rice blight, is assessed through in vitro studies. The biomass extract obtained is able to inhibit the growth of both the above-mentioned plant pathogens successfully. Mass spectroscopy analysis indicates the presence of Neophytadiene that has previously been reported for the inhibition of several pathogenic bacteria and fungi. Several other value-added products such as linoleic acid and nervonic acids were also been detected in the microalgal biomass which have extremely high nutraceutical and medicinal values. Furthermore, the study investigates the potential for co-production of biocrude from the biorefinery process via hydrothermal liquefaction. Overall, the findings of this present work represent an innovative and sustainable approach that combines wastewater treatment and crop protection using microalgal biomass. [ABSTRACT FROM AUTHOR]

Due to the natural energy sources used in constructed wetlands, minimal energy and chemicals are required for wastewater treatment. For the successful wastewater treatment via constructed wetlands, adequate pretreatment and a sufficient amount of oxygen are crucial. Constructed wetlands can be used to treat industrial wastewater, such as wastewater from the dairy industry, with prior degreasing. This study was conducted on a horizontal flow pilot constructed wetland located on a plot of land used by the Biotechnical Faculty in Bihać. The constructed wetland consisted of two fields planted with rushes (Typha latifolia) and reeds (Phragmites australis). The substrate and plants were not changed during the experimental period. We monitored the efficiency of industrial wastewater treatment (wastewater from the dairy industry) by season, varying the flow rate as well as the hydraulic retention time of the water in the device. The quality of the influent and effluent was monitored by determining analytical parameters. The constructed wetland showed the highest efficiency in the summer period, with a hydraulic retention time of 6 days, with removal efficiencies of 98.03% for ammonia, 98.19% for total nitrogen, 95.27% for total phosphorous, 94.50% for COD and 97.73% for BOD5. The organic substance removal efficiency across all four seasons was 94.68%. [ABSTRACT FROM AUTHOR]

Dairy industry is one of the leading consumer of water and producer of wastewater. Increased demand of dairy products results in rapid growth of dairy industry and hence wastewater production increases. Dairy effluent contains high concentrations of organic and inorganic substances that cause eutrophication in water bodies. This review study emphasizes on various treatment methods of DWW for period 2002 to 2022. Dairy wastewater imposes serious environmental concern because of the presence of wide range of fatty acids, proteins, nutrients, and other organics. These contaminants are difficult to treat in single step conventional treatment technique. In recent years much attention has been given for integrated system of dairy wastewater (DWW) treatment. The present review has deep insight for ongoing development in various treatment techniques of dairy wastewater. Moreover, this article intricate issue related with treatment followed by a brief discussion on the biological technique and special emphasis has been on the bio-filtration process. Extensive review study found that bio filtration method is environmentally sustainable and economically affordable technology as it requires minimal maintenance and low operating cost; filter media can be coarse gravel, stone, bio-carrier. Treatment process provides a separate area for the growth of necessary bacteria to complete their nitrogen cycle. Literature survey found that the bio-filtration process has the efficiency of removing BOD, COD, TP, TN (91.7–97.5, 74.1–99%, 98.3%, 88–91.5%). Fresh water crisis demands the reuse of DWW for non-potable purposes. Pre-treatment, anaerobic and aerobic biological processes are the most widely used DWW treatment techniques. Reuse of DWW in food, plastic, fuel, health and pharmaceutical industries helps to convert its zero value to a potential resource. [ABSTRACT FROM AUTHOR]

The article evaluates the effectiveness of two new designed module‐integrated three‐dimensional (3D) printed spacers in enhancing wastewater ultrafiltration efficiencies using vibratory shear‐enhanced processing (VSEP). The study investigates the star‐shaped spacer filled module channel (star spacer) and the column‐shaped herringbone spacer filled module channel with the same position as the flow direction (column spacer) and with the opposite position as the flow direction (rev column spacer). It compares the VSEP module‐integrated spacers with membrane module vibration (module vibration) and empty membrane module channel (control) configurations. The results show that the module integration of the 3D printed spacers can greatly improve the specific, average, and constant permeate fluxes and can contribute to reducing the total, reversible and irreversible resistance values, and specific energy consumption of the ultrafiltration membrane separation experiments. Overall, this study provides valuable insights into improving the performance of wastewater ultrafiltration systems and fouling mitigation through the module integration of 3D printed spacers and membrane module vibration. Practitioner Points: Vibratory shear‐enhanced processing (VSEP) ultrafiltration module‐integrated 3D printed spacers were successfully fabricated and evaluated for improved wastewater treatment.Two spacer designs, a star‐shaped and a column‐shaped herringbone, were compared with an empty membrane module channel with and without vibration.Two configurations of the column‐shaped spacer, in the same and reversed flow direction, were tested.Specific energy consumption was calculated and compared for all configurations.Significant improvements in ultrafiltration performance were observed with the use of spacers compared with an empty module channel, including enhanced permeate fluxes and reductions in both total and reversible, as well as irreversible, resistance. [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]

In this research, the methane potential of the codigestion of cattle manure (CM) with guinea pig manure (GPM) and dairy wastewater (DW) was evaluated. The effect of the addition of nutrients, inoculum (I) and co-substrates on methane production was studied. Later, two low-cost tubular biodigesters were implemented, at a rural farm in the cold climate municipality of Cumbal, fed with the mixture of CM and co-substrates that produced higher biogas production at the lab scale. The results evidenced that the addition of nutrients had no significant effect on methane potential. The mixture CM + GPM + DW + I, produced a theoretical biomethane potential (BMP) of 69.07%, significantly higher than the percentage of the theoretical BMP obtained individually, 43.81% and 34.49% for CM + I and DW+ I respectively. Further, it was observed that the addition of inoculum avoided problems of acidification. Finally, it was proved that this process can reduce environmental contamination and, at the same time, be a sustainable source of renewable energy for rural families in Cumbal (Nariño-Colombia). [ABSTRACT FROM AUTHOR]

Dairy sludge is one of the main and inexpensive wastes of the dairy industry, which contains the nutrients necessary for the growth of lactic acid bacteria (LAB) to produce microbial metabolites, and for its efficient use, optimization of fermentation conditions is critical. In order to optimize the production of dry biomass, three independent variables of dairy sludge concentration (5, 12.5 and 20%), pH (6, 7 and 8) and the inoculation rate of Lactobacillus fermentum strain 4-17 (1, 3 and 5%) were used. Before fermentation, the cell growth and morphology of this bacterium were examined in order to determine the function of the growth rate and confirm the presence of bacteria in this medium. The independent variables were optimized using response surface method (RSM) with central composite design (CCD) in order to maximize dry biomass production by this bacterium. The optimization results showed that the maximum amount of dry biomass production related to the optimal treatment included 20% dairy sludge concentration, 1% inoculation rate and pH 8. Also, according to the results, the dairy sludge substrate is suitable for the fermentation of this bacterium. As a result, the effect of dairy sludge bed concentration and pH on dry biomass production by this bacteria was very significant. [ABSTRACT FROM AUTHOR]

Currently, microalgae have become a marvelous and resource-friendly alternative source of advantageous bioproducts, such as lipids, carbohydrates, proteins, or other bioactive compounds. Because of the richness of microalgae in these high-value-added metabolites, still, it is an underdeveloped source of sustainable energy and food. There are some hurdles to profitable production, such as culture contamination and costly harvesting techniques. In the current work, a chrysophyte was isolated from dairy wastewater, identified as Poterioochromonas malhamensis based on its morphology and partial 18S rRNA gene sequences. This isolate was used to remediate dairy wastewater (DWW) and to obtain neutral lipids (fatty acids) from microalgae. Microalgal growth was optimized by using different concentrations of DWW, supplemented with all the nutritive requirements for better progression and flourishment. Maximum biomass yield 1.478 g L−1 was achieved by optimized cultural conditions (different concentrations of DWW with BBM media). This strain showed high nitrate and phosphate removal efficiency (87.45% and 88.96%), respectively in 15 days. The experimental results highlighted that the lipid content and the chemical oxygen demand (COD) removal were 31.60% and 88.84%, respectively and the lipid profile of isolated microalga was C16:0, C16:1, C18:0, C18:1, and C18:2 fatty acids. For growth and treatment purposes, 75% DWW with Bold’s Basal Medium (BBM) media showed better results. This is the first report of DWW treatment using the microalga Poterioochromonas malhamensis, as far as we are aware. Its cultivation prevented the spread of pollution of freshwater sources, remedied the DWW, and generated important lipids for industry. [ABSTRACT FROM AUTHOR]

Acid-casein production generates waste streams that are rich in nitrogen (in the form of protein and nitrate) and phosphate. This makes this type of waste very difficult to treat using conventional techniques resulting in a high amount of operating cost and costly investment. In this research, the application of single culture or consortium of microalgae for uptake of nitrogen and phosphate in the wastewater of an acid-casein factory was investigated. The waste was a 1:1 mixture of nanofiltered whey permeate and dairy processing wastewater. Monocultures of Chlorella vulgaris, Tetradesmus obloquus, Nonnochlropsis ocenica and a consortium of the three microalgae were analyzed. The results showed that the consortium exhibited more efficient nitrogen and phosphate removal compared to the individual species. The consortium was able to rapidly hydrolyse exogenous protein present in the waste medium, removing 88% of protein and breaking down complex protein molecules into simpler compounds (such as nitrate) for assimilation into the biomass. In the first fourteen days of cultivation, the rate of nitrate assimilation by the consortium biomass was lower than that of nitrate formation from protein degradation, leading to a net increase in nitrate concentration in the medium. As protein source was depleted and biomass concentration increased, however, the rate of nitrate assimilation began to exceed that of nitrate formation allowing for net removal of nitrate. The microalgae consortium was shown to successfully bioremediate all nitrates by day 21. It was indicated that Chlorella and Nannochloropsis species were responsible for nitrogen removal in monocultures. Phosphate, on the other hand, was efficiently removed by Tetradesmus. The results indicated that a consortium cultivation of three species of microalgae led to effective elimination of both nitrogen and phosphate. Combined flow-cytometry and microscopy analyses revealed that Chlorella overtook Tetradesmus and Nannochloropsis to emerge as the dominant population in the consortium by the end of the cultivation cycle. It can be concluded that the application of microalgae consortium for simultaneous recovery of nitrogen and phosphate is a promising approach for treating acid-casein wastewater. • Growth of microalgae on whey permeate from acid casein processing were analyzed. • Flowcytometry and microscopic analysis confirmed the successful growth of microalgae. • The use of a consortium culture exhibited efficient nutrient removal approach. • Microalgae depleted phosphate and exhibited proteolytic activity. • Application of microalgae for nutrient recovery from acid casein wastewater is promising. [ABSTRACT FROM AUTHOR]

This study aimed to develop a mathematical index for quantifying filter bed clogging in horizontal subsurface flow macrophyte‐assisted vermifilter (HSSF‐MAVF). The developed clogging index (CI) simulates the porosity reduction in the HSSF‐MAVF bed due to the combined actions of deposition of suspended solids, biofilm generation, and plant growth. A series of experiments based on HSSF‐MAVF were conducted to examine the key parameters related to clogging of the vermifilter such as hydraulic loading rates (HLR), organic strength (COD), and total suspended solid (TSS) at different operating conditions for the treatment of synthetic dairy wastewaters. The index was then validated using the data collected from the experiments. The predicted CI was observed to be highly capable of replicating the clogging phenomenon, as observed in this experimental study within the error range of 2–8%. Based on the visual observation and value of CI, filter beds can be grouped as unclogged (CI < 25), partially clogged (25 < CI < 40), and clogged (40 < CI). Clogged filter beds with higher CI resulted in a 5–15% reduction in the COD removal performance of HSSF‐MAVFs. Moreover, the CI also envisages one to understand the individual contributions of biofilm growth, suspended solid deposition, and plant roots growth on the filter bed clogging during the operation of vermifilter and thus helps in deciding the proper setting of operational conditions to prolong the time of HSSF‐MAVF operations within the acceptable range of bed materials clogging. Practitioner Points: A mathematical index was developed to quantify clogging of the HSSF‐MAVF.Flow is the most sensitive parameter based upon the sensitivity analysis.Dairy wastewater was used for the validation of CI. [ABSTRACT FROM AUTHOR]

Dairy industry wastewater with high levels of nutrients and organic matters can adversely affect water bodies, and ecosystems. Therefore, there is an immediate need to treat such wastewaters before discharge. The dairy wastewater is acceptable to aerobic biological treatment. Given that these processes are generally failed by organic loading shocks, this work attains to solve the issue through innovative operation modes of integrated fixed-film activated sludge process for aiming to break high organic loads and better biodegradation of high-strength wastewaters. In order to achieve the purpose, two novel bioreactors were designed and operated with employing cycle times of 2.5–4.5 h at an OLR of 2.93–16.8 KgCOD/m3.d. The kinetic models and artificial neural networks (ANNs) were applied to reach a better realisation of the data and to predict the optimum retention time. The results show that the bioreactors obtained more than 97% of organic matter removal. In addition, based on kinetic coefficients, the high performance of the bioreactors is proved. Therefore, the investigated processes could be of interest as a suitable treatment process. [ABSTRACT FROM AUTHOR]

A milk-processing plant was drafted as a distinctive staple industry amid the diverse field of industries. Dairy products such as yogurt, cheese, milk powder, etc., consume a huge amount of water not only for product processing, but also for sanitary purposes and for washing dairy-based industrial gear. Henceforth, the wastewater released after the above-mentioned operations comprises a greater concentration of nutrients, chemical oxygen demand, biochemical oxygen demand, total suspended solids, and organic and inorganic contents that can pose severe ecological issues if not managed effectively. The well-known processes such as coagulation–flocculation, membrane technologies, electrocoagulation, and other biological processes such as use of a sequencing batch reactor, upflow sludge anaerobic blanket reactor, etc., that are exploited for the treatment of dairy effluent are extremely energy-exhaustive and acquire huge costs in terms of fabrication and maintenance. In addition, these processes are not competent in totally removing various contaminants that exist in dairy effluent. Accordingly, to decrease the energy need, microbial electrochemical technologies (METs) can be effectively employed, thereby also compensating the purification charges by converting the chemical energy present in impurities into bioelectricity and value-added products. Based on this, the current review article illuminates the application of diverse METs as a suitable substitute for traditional technology for treating dairy wastewater. Additionally, several hindrances on the way to real-world application and techno-economic assessment of revolutionary METs are also deliberated. [ABSTRACT FROM AUTHOR]

One of the main limitations to the use of microalgae in various fields is the high production cost and low amount of biomass produced. In this study, the utilization of dairy wastewater as a culture medium to lower costs and the application of growth stimulants, gibberellic acid (GA3) and indole-3-acetic acid (IAA) to enhance biomass production in Dunaliella salina was investigated. The amount of fresh and dry weight, chlorophyll, carotenoid, protein and soluble sugar obtained from D. salina cultivation in wastewater was higher than in Artificial Seawater medium. An approximately 2-fold increase in fresh and dry weight was observed in microalgae treated with 1 µM GA3. Also, the lowest concentration of GA3 (1 µM) increased the amount of chlorophyll a, b and carotenoid by 2.24, 3 and 2.4 times, respectively, compared to untreated wastewater. IAA at 100 µM concentration caused a 1.6 and 1.8-fold increase in fresh and dry weight, respectively. The amount of chlorophyll a, b and carotenoids in microalgae treated with 100 µM IAA increased by 4, 2 and 5.6 times, respectively. The rate of increase in protein and soluble sugar was 33 and 48% respectively compared to untreated wastewater. In simultaneous treatment only the amount of fresh and dry weight, chlorophyll b and soluble sugar increased at highest concentration of both phytohormones. The results of this research showed that the use of phytohormones to increase the growth of microalgae in the wastewater environment in order to obtain more biomass and thus increase the performance of algae in wastewater treatment, could be a suitable solution. [ABSTRACT FROM AUTHOR]

Aim- The aim of this research is to compare suspended growth reactors MBR and SBR to calculate the organic content reduction efficacy offered by the reactors for different concentrations of wastewater from the dairy industry. Materials and methods - The secondary treatment reactors, MBR and SBR having an average Organic Loading Rate (OLR) of 0.55 g/m3/d to 1.11 g/m3/d, were compared for their Biological Oxygen Demand (BOD5) removal efficacy for a period of 5 consecutive days for wastewater effluents from dairy industries such as mixed dairy, cheese, cheese whey, milk permeate, butter, dairy sewage, ice cream. Test samples (N = 14) were taken from the outfall of the experimental group (MBR) and control group (SBR) using G Power software. G power is taken as 0.8. Results- The performance of an individual MBR reactor at removing the BOD5 content was 95% compared to an individual SBR reactor which showed only 65%. On the other hand, the treatment plant as a whole which employed MBR reactor showed a removal efficacy of 84% and the plant which employed SBR reactor showed only 70% removal efficacy of BOD5. The significance value is determined as 0.04 (p is less than 0.027, statistically significant) based on SPSS analysis. Conclusion - MBR not only showed a better efficacy at removing BOD5 from the dairy wastewater but was also cost efficient ($7.59) than SBR ($11.53), the only downside to the MBR reactor was that it utilised more power of 62.82 kW than that of SBR (44.71 kW). MBR showed a lesser efficacy of 52% for treating the effluents from ice cream which had an OLR of 0.156 g/m3/d and the reactor showed its highest efficacy of 99.8 % for treating milk permeate effluents of having an OLR of 1.73 g/m3/d. [ABSTRACT FROM AUTHOR]

This research work was carried out to evaluate the kinetic constants for the biological treatment of dairy industry wastewater in a suspended growth batch reactor. The study was performed in a lab-scale batch reactor which is a prototype of an aeration tank unit of the activated sludge system. Samples of dairy wastewater were collected from a dairy plant near Kolkata on regular time interval and in different seasons of a year to establish mean values of the major wastewater parameters. A synthetic simulated sample was made on the basis of evaluated characteristics of dairy wastewater. Kinetics study in batch reactor was done to find kinetic coefficients (Y, Ks, kd and k). The value of the maximum substrate removal rate (k) at preliminary concentration of COD 700–720 mg/L was 4.42 day−1; half velocity constant (Ks) was 206.81 mg/L and k value at initial NH4+–N level of 48–54 mg/L was found 2.5 per day, Ks was 24.5 mg/L. Isolation and identification of the most potent strains for the carbon oxidation and nitrification was also done and by using those isolated strains kinetic coefficients for pure culture was determined. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to investigate the ability and efficiency of the biological treatment to reduce dairy wastewater pollutants by reaching acceptable limits for safe discharging using indigenous bacteria. Ten indigenous bacteria (DM1-DM10) were isolated from dairy wastewater effluent and screened for decontamination process for 7 days. Quality parameters including biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO) and total viable count of bacteria (TVCB) were determined before and after the bioassay and their removal efficiencies (REs) were calculated. The three most promising screened bacterial strains were molecularly identified and used as individual or mixed free-living cultures in a batch mode remediation assay. Results showed a general trend of increasing the REs of all parameters by all the tested bacteria with increasing the exposure time. Strains DM5 {Bacillus Cereus ATCC14579 (NR114582.1)}, DM6 {(Bacillus Aerius 24 K (NR-118439.1)} and DM7 {Bacillus cereus ATCC14579 (NR-074540.1)} recorded the highest activity for removing the selective pollutants, while strains DM2, DM8 and DM10 recorded the lowest removal efficiency for the same parameters. Therefore, DM5, DM6 and DM7 were used as individual and mixed free-living cultures in a batch mode remediation process. Raw dairy wastewater contains a very high level of COD (7680 mg/l), BOD (2700 mg/l) and a high level of TSS (1923 mg/l) indicating high organic load and suspended particles. It also contained an intermediate level of TDS (1220 mg/l) and a low DO level (0.49 mg/l) due to high organic contents and high microbial oxidation demand. Bacillus cereus ATCC14579 (DM7) showed the highest removal efficiency of BOD (78.11), COD (88.66%) and TSS (70.10 %) from dairy wastewater. It also exhibited the highest increase in TDS (59.10 %) and DO (389.89%). However, the mixed culture showed the lowest removals for the included contaminants. Moreover, DM7 showed the highest biomass yield (growth stimulation) during the batch mode treatment bioassay where it possesses the highest ability to biodegrade and benefit from the organic pollutants in the dairy effluents for its growth among all tested strains. Results of the present study confirmed that DM7 {Bacillus cereus ATCC14579 (NR-074540.1)} is the most promising for either minimization or decontamination of pollution load (mostly organic) from the dairy wastewater. [ABSTRACT FROM AUTHOR]

This study investigated the potential of granular activated carbon (GAC) supplementation to enhance anaerobic degradation of dairy wastewater. Two sequential batch reactors (SBRs; 0.8 L working volume), one control and another amended with GAC, were operated at 37°C and 1.5–1.6 m/h upflow velocity for a total of 120 days (four cycles of 30 days each). The methane production at the end of each cycle run increased by about 68%, 503%, 110%, and 125% in the GAC‐amended SBR, compared with the Control SBR. Lipid degradation was faster in the presence of GAC. Conversely, the organic compounds, especially lipids, accumulated in the absence of the conductive material. In addition, a reduction in lag phase duration by 46%–100% was observed at all four cycles in the GAC‐amended SBR. The peak methane yield rate was at least 2 folds higher with GAC addition in all cycles. RNA‐based bacterial analysis revealed enrichment of Synergistes (0.8% to 29.2%) and Geobacter (0.4% to 11.3%) in the GAC‐amended SBR. Methanolinea (85.8%) was the dominant archaea in the biofilm grown on GAC, followed by Methanosaeta (11.3%), at RNA level. Overall, this study revealed that GAC supplementation in anaerobic digesters treating dairy wastewater can promote stable and efficient methane production, accelerate lipid degradation and might promote the activity of electroactive microorganisms. [ABSTRACT FROM AUTHOR]

Wastewater from the livestock industries contains high concentration of nutrients, organic pollutants, suspended solids, and pathogenic microorganisms. Discharge of livestock wastewater without proper treatment can therefore cause serious pollution, calling for advanced treatment methods. For instance, electrochemical treatments are gaining attention because they are clean and flexible. Compared to conventional biological treatment methods, electrochemical processes exhibit higher pollutant removal efficiencies within shorter time periods. Here, we review the electrochemical treatment of livestock wastewater with focus on electrocoagulation, electrooxidation, and electro-disinfection. We present factors controlling effective process design and operation. Pollutants removal from livestock wastewater, economic analysis, and scaling-up considerations are also discussed. The oxidation of electrodes during electrocoagulation induces periodical replacement and thus influences the operational cost. Dimensionally stable metal oxide-layered titanium electrodes such as Ti/PbO2, Ti/RuO2, Ti/IrO2, and Ti/IrO2–Ta2O5–Pt are becoming popular due to their stability. Reactor design and operational parameters govern the effectiveness of the treatment process. Further pilot-scale studies are required to scale up and demonstrate the potential of electrochemical livestock wastewater treatment techniques. [ABSTRACT FROM AUTHOR]

Chemical coagulation has gained recognition as an effective technique to enhance the removal efficiency of pollutants in wastewater prior to their entry into a constructed wetland (CW) system. However, its potential impact on the chemical and microbial properties of soil and plant systems within CWs requires further research. This study investigated the impact of using ferric chloride (FeCl 3) as a pre-treatment stage for dairy wastewater (DWW) on the chemical and microbial properties of water-soil-plant systems of replicated pilot-scale CWs, comparing them to CWs treating untreated DWW. CWs treating amended DWW had better performance than CWs treating raw DWW for all water quality parameters (COD, TSS, TP, and TN), ensuring compliance with the EU wastewater discharge directives. Soil properties remained mostly unaffected except for pH, calcium and phosphorus (P), which were lower in CWs treating amended DWW. As a result of lower nitrogen (N) and P loads, the plants in CWs receiving FeCl 3 -amended DWW had lower N and P contents than the plants of raw DWW CWs. However, the lower loads of P into amended DWW CWs did not limit the growth of Phragmites australis, which were able to accumulate trace elements higher than CWs receiving raw DWW. Alpha and Beta-diversity analysis revealed minor differences in community richness and composition between both treatments, with only 3.7% (34 genera) showed significant disparities. Overall, the application of chemical coagulation produced superior effluent quality without affecting the properties of soil and plant of CWs or altering the functioning of the microbial community. [Display omitted] • Wastewater pre-treatment using FeCl 3 improved the performance of CWs. • FeCl 3 pre-treatment had no negative effects on soil and plant properties. • FeCl 3 pre-treatment did not alter microbial community diversity and composition. [ABSTRACT FROM AUTHOR]

Dairy industries are highly polluting, energy and fresh water consuming installations. The present study aims to make dairy effluent treatment plant operation less time consuming with minimal energy consumption while generating a value added product. Analysis of the temporal and spatial variation in performance of a biofilm based plug flow reactor involved in the biotransformation of Dairy Waste Water (DWW) revealed ammonia (57.68 mg L–1) rich liquid biofertilizer production within 4 h, with associated reduction of nitrate (70.77%), phosphate (36.44%), protein (62.87%), Biological Oxygen Demand (BOD) (26.38%) and Chemical Oxygen Demand (COD) (39.59%). The process was 4 times faster than the fastest existing process reported till date. The consortium showed a striking reduction in its doubling time from 78 min 56 sec (in suspension culture) to 17 min 10 sec (as biofilm) upon immobilization. It could produce 734.60 mg ammonia per kg of immobilization matrix from DWW. Metagenomic analysis revealed the robustness of the biofilm based biotreatment system. The novelty of this study is the innovative approach of rapid conversion of the waste from dairy industry into a value added product using microbes from geosphere in an energy efficient manner which would make dairy effluent treatment plant operation self-sustainable and eco-protective. [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]

The supercritical water gasification (SCWG) of real dairy wastewater (cheese-based or whey) was performed in a batch reactor in presence of two catalysts (MnO 2 , MgO) and one additive (formic acid). The operational conditions of this work were at a temperature range of 350–400 C and the residence time of 30–60 min. The catalysts and formic acid were applied in 1 wt%, 3 wt%, and 5 wt% to determine their effect on hydrogen production. The concentrations of catalysts and formic acid were calculated based on the weight of feedstock without ash. The results showed that increased temperature and prolonged residence time contributed to the hydrogen production (HP) and gasification efficiency (GE). The gas yield of hydrogen in the optimum condition (400 C and 60 min) was achieved as 1.36 mmol/gr DAF (dry ash free). Formic acid addition was favored towards enhancing hydrogen content while the addition of metal oxides (MnO 2 and MgO) had an apex in their hydrogen production and they reached the highest hydrogen in 1 wt% concentration then ebbed. Moreover, GE was increased by the addition of the catalysts and formic acid concentrations. The highest hydrogen content (35.4%) was obtained in 1 wt% MnO 2 and the highest GE (32.22%) was attained in the 5 wt% formic acid concentration. A reaction pathway was proposed based on the GC-MS data of feedstock and produced liquid phase at different condition as well as similar studies. [Display omitted] • The higher temperature and prolonged residence time enhanced the hydrogen production and gasification efficiency. • The order of catalytic activity for the hydrogen production was MnO 2 > Formic acid > MgO. • Increasing temperature resulted on elimination of acidic/phenol compounds and reducing the nitrogen-containing compounds. • A reaction pathway of supercritical water gasification of cheese-based wastewater was proposed. [ABSTRACT FROM AUTHOR]

Microalgae are one of the promising unicellular species for biosynthesis of functional natural products, such as omega-3 long-chain polyunsaturated fatty acids, carotenoids, proteins, and vitamins. As they readily grow on organic and nitrogenous substrates, they have vast phycoremediation potential for different industrial wastewater and side-streams. The side-streams from dairy industry have the enormous potential of valorization as they have high carbon and nutrient load, which could serve as growth media for microalgal cultivation. This review addresses the most recent examples of valorization of several types of dairy side-streams using microalgae. The aim is to provide better understanding of the issues and challenges of valorizing the industrial dairy side-streams as substrates for value added microalgal biomass production with focus on nutrient, particularly lactose utilization by using different microalgae species, mostly from Chlorella , Scenedesmus , and Spirulina genera. So far, mixotrophic and heterotrophic microalgae cultivation has been tested in various genuine and model dairy side-streams, wherein mixotrophic cultivation exhibited better biomass productivity. Moreover, this review identifies microalgae cultures capable of nutrient utilization and lactose assimilation, providing valuable guidance for future research in phycoremediation of dairy side-streams for value-added food production. Further investigations on different microalgal species for lactose utilization and β-galactosidase activity in model media are required to enable efficient valorization of lactose in the side-streams. • Dairy side-streams are feedstock for algal biomass production for functional food. • Mixotrophic cultivation of microalgae is a low-cost biomass production strategy. • Selection of lactose utilizing microalgae species is crucial. [ABSTRACT FROM AUTHOR]

In this study, Haematococcus pluvialis and Coelastrella saipanensis were evaluated for heterotrophic nutrition potential in dairy waste medium by blocking the PSII using DCMU. The study was done by four sets of experiments. In the first set, in the different concentrations DCMU-treatments, 20μL showed pronounced effect in H. pluvialis and C. saipanensis as 89 % and 83% decrease in cells (>30 and > 250 cells/mL) compared to control (536 ± 12.35 × 104 and 1167 ± 15.35 × 104 cells/mL, respectively). Damage to the PS II by DCMU interrupted the growth, which in turn produced a significant drop in the number of cells. In the second round of experiment, growth of algae in various dairy waste concentrations suggest that dairy wastewater (DWW) provides enough nutrients to produce 35.71 % and 64.74 % more cells in H. pluvialis and C. saipanensis, respectively compared to the control. In the third set, high DCMU concentration was added to microalgae cultures in DWW to assess the heterotrophic nutrition potential. Growth in cell number 34.4 ± 19 and 617.46 ± 60.44 cells/mL was recorded in H. pluvialis and C. saipanensis when grown control medium whereas addition of DCMU reduced the cell number to 1.53 ± 0.75 and 55.13 ± 0.75 cells/mL on 15th day, respectively. This shows cells in cultures treated with DCMU reveal that algae can sustain their metabolic activity by utilizing the nutrients of dairy waste inhibiting photosystem. Fourth round of experiments found that microalgae could resume their growth and productivity by adapting to heterotrophic nutritional behaviour when DCMU given in mild dose at different time interval. This study conclude as C. saipanensis grows more readily by absorbing dairy waste nutrients than H. pluvialis. Therefore, C. saipanensis is an excellent choice for wastewater treatment through sustainable environmentally benign process after scale-up investigation. These results provide useful information to advance to molecular study for measuring microalgae's capability for bioremediation application. [Display omitted] • Dairy waste nutrients are an efficient substrate for the growth of H. pluvialis and C. saipanensis. • These algae can thrive in the waste medium by utilizing the available nutrients by disabling phtosystem II using DCMU. • DCMU can be used to measure the microalgae capability of adaptation to heterotrophic nutrients. • In light of this, both algae, C. saipanensis in particular, is a good candidate for wastewater cleanup. [ABSTRACT FROM AUTHOR]

The increasing demand for dairy products has led to the production of a large amount of wastewater in dairy plants, and disinfection is an essential treatment process before wastewater discharge. Disinfection byproducts (DBPs) in disinfected dairy wastewater may negatively influence the aquatic organisms in receiving water. During chlorine and chloramine disinfection of dairy wastewater, the concentrations of aliphatic DBPs increased from below the detection limits to 485.1 μg/L and 26.6 μg/L, respectively. Brominated and iodinated phenolic DBPs produced during chlor(am)ination could further react with chlorine/chloramine to be transformed. High level of bromide in dairy wastewater (12.9 mg/L) could be oxidized to active bromine species by chlorine/chloramine, promoting the formation of highly toxic brominated DBPs (Br-DBPs), and they accounted for 80.3% and 71.1% of the total content of DBPs in chlorinated and chloraminated dairy wastewater, respectively. Moreover, Br-DBPs contributed 49.9–75.9% and 34.2–96.4% to the cumulative risk quotient of DBPs in chlorinated and chloraminated wastewater, respectively. The cumulative risk quotient of DBPs on green algae, daphnid, and fish in chlorinated wastewater was 2.8–11.4 times higher than that in chloraminated wastewater. Shortening disinfection time or adopting chloramine disinfection can reduce the ecological risks of DBPs. [Display omitted] • There is a high level of bromide (12.9 mg/L) in the dairy wastewater. • The formed bromo- and iodo-phenolic DBPs can be further degraded by chlor(am)ine. • Shortening the disinfection time can reduce the ecological risks of DBPs. • Chloramine disinfection is more conducive to reducing the ecological risks of DBPs. [ABSTRACT FROM AUTHOR]

Microalgae are known to have higher growth rates than terrestrial plants and are garnering great attention among researchers as they can produce commodities of high commercial value. Remediating wastewater with microalgae and utilizing it as a biofertilizer could significantly improve the economic standpoint of algal production. In this study, varying concentrations (0%, 40% and 60%) of aqueous cell extracts of Chlorella variabilis and Scenedesmus obliquus cultivated on dairy wastewater were used as a biofertilizer to evaluate plant growth of corn (Zea mays) and soybean (Glycine max) up to the mid vegetative stage. The treatments that employed the microalgal consortia as biofertilizer (40% and 60%) exhibited increased growth rates, higher total phenolic content, total flavonoid content, antioxidant activity and minerals when compared to the control group for both corn and soybean. [ABSTRACT FROM AUTHOR]

Dairy wastewater in the literature has been treated using different electrochemical methods, but none of them applied a simultaneous hybrid electrocoagulation-electrooxidation (EC-EO) system. In this study, a hybrid EC-EO process was tested for its efficiency on COD and turbidity removal. Mainly the monopolar and bipolar connections using iron, aluminum, and oxidized titanium as electrode materials were tested within the EC-EO system. The results obtained showed better COD removal efficiency for the bipolar connection mode. However, low metal dissolution levels were registered for the monopolar connection mode. Besides, the bipolar connection mode was found to cost higher than the monopolar one. [ABSTRACT FROM AUTHOR]

Due to the growing demand for energy in the present-day world, it is obligatory to look for alternative sources of renewable energy. The derivation of power from microbial fuel cells (MFCs) has developed at the vanguard of the alternative source of renewable energy through the concomitant treatment of wastewater. Hence, the process development of MFC is obligatory for creating a sustainable source of renewable energy through the treatment of wastewater. To that end, an attempt was taken in the present study for sustainable power generation from single chamber microbial fuel cell (SCMFC) using Pseudomonas aeruginosa-MTCC-7814. The experiments were carried out in a batch process for 15 days with real dairy wastewater (RDW) having initial chemical oxygen demand (COD) of 8000 mg/L. The open-circuit voltage (OCV) found after 72 h of batch operation was 658 mV, which was maximum within the batch operation. The columbic efficiency (CE) of the batch process was found to be 46.59%. The maximum specific growth rate (μ max) of Pseudomonas aeruginosa -MTCC-7814 was found to be 0.432 day−1 during batch operation. However, saturation constant (Ks) and inhibition coefficient (K i) were calculated as 608.74 mg/L, and 6582 mg/L, respectively. The maximum current density (I max) and saturation constant (K c) predicted from batch kinetics study were 132 mA/m2 and 321 mg/L, respectively, which has resemblance with the data obtained from experiments. The maximum current density and power density from experiments were found to be 161 mA/m2 and 34.82 mW/m2, respectively. Results showed that a higher power density and current density values were obtained from the present study as compared to the earlier reports that utilized wastewater as the substrate for the MFC. Thus, the study suggests that Pseudomonas aeruginosa , (MTCC -7814) can be used as a promising biocatalyst in MFC for sustainable power generation through the utilization of wastewater treatment. • Batch process for power generation from real dairy wastewater. • 94.40% of COD removal efficiency and 46.59% of columbic efficiency were found. • 161 mA/m2 of current density and 34.82 mW/m2 of power density were achieved. [ABSTRACT FROM AUTHOR]

Large volume of dairy wastewater has caused a great threat to the ecological environment, due to the difficulty to treat it. Traditional treatment requires more heating energy at the least temperature of 36 . Alternatively, non ℃ -hazardous fertilizers are widely expected to treat wastewater, particularly easy soluble in water to transfer through dripping or spraying irrigation. However, the chemical fertilizers derived from wastewater contain many organic matters and nutrients, resulting in the blockage of spray nozzles. In this study, a feasible bio-treatment of dairy wastewater was proposed using the low-temperature anaerobic fermentation, thereby lowering energy consumption, while increasing the fluid permeability through dripping or spraying irrigation. The treated dairy wastewater was observed in the anaerobic fermentation at low temperatures (10-25 ℃) through an array of time points by no inoculants, as well as at a normal temperature of 36 ℃ by inoculants of granular anaerobic sludges. A full-length 16S rRNA gene sequencing was used to detect microbiological compositions. Response surface analysis was performed on fermentation parameters. The results showed that there was a significant influence of anaerobic fermentation under low temperature on the sediment characteristics of dairy wastewater. The sedimentation and layering performance of wastewater were significant under the condition of 9 days at 10 ℃, where the turbidity of supernatant was about 5. The most energy-efficient and economical condition was at 15 ℃ in the 4d for the low-temperature anaerobic treatment. There was an average energy saving of 2 865 kW·h/d by l5 ℃ anaerobic fermentation with ambient temperature around 7.8 ℃, compared with fermentation at 36 ℃. Low-temperature anaerobic fermentation changed the sedimentation characteristics of wastewater over a longer time but with equal quality, where supernatant CODCr was reduced to (2 627.8±548) mg/L, nitrogen to (565.2±79.5) mg/L, fecal coliforms to around 360/L, the residue ratio of the dry filter by mesh diameter 75 μm filters approximately to 0 %. The dry matter ratio of supernatant dropped from 18.9% to 2.3% after treatment, while 50% of wastewater was recycled as irrigation water, where the total nutrients (N+P2O5+K2O) content of supernatants were 1.744 9 g/L. The number of fecal coliforms reduced down to 360 g/L, while, the mortality ratio of ascarid egg was above 95%. Both granular and low-temperature sludges showed the treating functions of wastewater (methanogenesis and wastewater turbidity change), but with different efficiency, where 199 otu were detected in the anaerobic sludges via the full-length 16S rRNA gene sequencing, while 207 otu in the acclimatized granular anaerobic sludges, and 96 otu were common in both sludges. Candidatus Cloacimonas was a dominant species in the long-term (over 6 mon) low-temperature conditioned anaerobic sludges, while genus Sulfurovum dominated in inoculated granular anaerobic sludges. In the study site with the mean annual temperature of 4.1 ℃, low-temperature (15 ℃) anaerobic fermentation saved much more energy consumption than the thermal anaerobic fermentation (36 ℃). The supernatant was transformed to the nuzzle irrigation, indicating that the environmental non-hazardous proxies met with the discharge requirements of the national standard. About 1.7449 g/L total nutrients and 50 % water resources were recycled in total. The finding can provide a potential application for future recycling in agriculture and sustainable development. [ABSTRACT FROM AUTHOR]

According to the concept of circular economy, food industry wastewater should be considered a secondary raw material that could be exploited, thus reducing the resources escaping from the production system. We aimed to assess the circular sustainability of dairy wastewater treatment by evaluating the possibility of transforming it from a cost to a valuable resource. We tested the non-photosynthetic WSZL mutant of Euglena gracilis as a bio-remediating organism for raw dairy wastewater to recover the resources herein present for biomass growth and simultaneously provide a source of paramylon, a high commercial value glucan. This mutant is an obligate osmotroph, which can synthesize paramylon up to 90% of the cell dry weight with the proper carbon source. We tested the mutant on the wastewater produced by a small dairy facility located near Pisa (Italy) using an indoor bench-scale fermenter allowing the alga to grow inside a dialysis tubing immersed in the effluent. We monitored the effluent variation of biochemical oxygen demand (BOD5), soluble chemical oxygen demand (COD), total suspended solids (TSS), ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), orthophosphate (PO43--P), electric conductivity and pH. The alga can reduce the pollutant concentration to values allowing indirect discharge of the wastewater into public sewage plants and can be therefore considered a promising organism for tertiary treatment of dairy wastewater. The cells produced about 2.6 g L-1 of paramylon from 3.2 g L-1 biomass, an amount greater compared with that produced by batch cultures, confirming the possibility of recovering wastewater resources and transforming them in a high-value product. [ABSTRACT FROM AUTHOR]

This study investigated precipitation of struvite from dairy wastewater. The results indicated that pH of the solution exhibited a significant effect on phosphate recovery and purity of struvite. Results showed that 95% of phosphate was recovered from solution at MgO:P molar ratio of 4:1 and pH 9.5. Furthermore, struvite precipitation was optimized using response surface methodology; Visual MINTEQ was used to identify the speciation and precipitation potential of solid phases at different pH. Economic evaluation study revealed that recovery of struvite from phosphorous rich wastewater considerably reduces the chemicals requirement and associated sludge transportation and disposal. [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]

Membrane separation processes for wastewater treatment in dairy industry gives so many benefits such as less ecological footprint, reliable contaminant removal, low cost, possibility of renewable energy use, simple technology and can easily integrate with other processes. However, the fouling issue limits its widespread application. Self-cleaning membrane technology, through membrane modification by heterogeneous photo-catalytic nanomaterials and their composites, has been given more attention by many researchers. In this paper, characteristics of dairy wastewater and possible membrane separation processes applications in dairy wastewater treatment are summarised and discussed. Fouling mechanisms of protein, the interaction of molecules, factors affecting fouling are highlighted. Physical, chemical, and self-cleaning fouling control and mitigation strategies are reviewed. Membrane modifications by renewable or non-renewable energy-driven heterogeneous photo-catalysis and possible ways that enhance the photocatalytic efficiency are also addressed. Finally, challenges and prospective solutions are reviewed. [ABSTRACT FROM AUTHOR]

Water is one of the most used resources in this planet and the amount of fresh water available for everyday use is a very small percentage. There is a huge water scarcity in many places around the world and apart from this, many of the water sources around the world are contaminated with harmful chemicals and other biologically harmful substances and that is a huge risk for the survival of the aquatic animals and sometimes even for humans and for these reasons, the wastewater should be treated before it is sent out of the industry. This work focuses on the treatment of dairy wastewater as dairy industry being one of the highest consumers of fresh water. This work is performed on a simulant and using acid to agglomerate particles and a membrane filter to filter the wastewater after the coagulated particles are separated by decantation or any similar methods. Various tests were performed before and after the filtration to measure a series of parameters of which turbidity and total suspended solids had significant decrease percentage. The other parameters had a comparatively less percentage decrease with pH of the wastewater remaining almost the same. This proved to be a costeffective method to treat dairy wastewater. [ABSTRACT FROM AUTHOR]

Hydrogen (H 2) generation from cheese whey with simultaneous production and extraction of volatile fatty acids (VFAs) was studied in UASB reactors at two temperatures (20 and 35 °C) and pH values (5.0 and 4.5). The extraction module, installed through a recirculation loop, was a silicone tube coil submerged in water, which allows concentration-driven extraction of undissociated VFAs. Operating conditions were selected as a compromise for the recovery of both H 2 and VFAs. Batch experiments showed a higher yield (0.9 mol H 2 mol−1 glucose eq.) at 35 °C and pH 5.0, regardless of the presence of the extraction module, whereas lower yields were obtained at pH 4.5 and 20 °C (0.5 and 0.3 mol H 2 mol−1 glucose eq. , respectively). VFAs crossed the silicone membrane, with a strong preference for butyric over propionic and acetic acid due to its higher hydrophobicity. Sugars, lactic acid and nutrients were retained, resulting in an extracted solution of up to 2.5 g L−1 butyric acid with more than 90% purity. Continuous experiment confirmed those results, with production rates up to 2.0 L H 2 L−1 d−1 and butyric acid extraction both in-line (from the UASB recirculation) and off-line (from the UASB effluent). In-line VFA extraction can reduce the operating costs of fermentation, facilitating downstream processing for the recovery of marketable VFAs without affecting the H 2 production. Image 1 • Cheese whey fermentation was studied in UASB rectors with in-line VFA extraction. • Butyric acid was selectively extracted from the broth using a silicone membrane. • Sugars, lactic acid, and nutrients are retained by the silicone membrane. • HPR up to 2 L L−1 d−1 and butyric acid extraction up to 2.5 g L−1 were achieved. • pH 4.5 enhances VFA migration through the silicone membrane but decreases H 2 yields. [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]

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]

This study pointed out the performance of a full-scale internal circulation (IC) bioreactor (140 m3) inoculated with anaerobic granular sludge for the treatment of dairy wastewater for 91 days. The average COD removal was 80% and the average biogas was 69.8 m3 per influent COD/L per day. Then the anaerobic digestion of cheese whey (CW) at a pH 5–6 was examined at a laboratory level as a strategy to reduce the requirement for alkalinity. First, anaerobic granular sludge from IC bioreactor (pH 7–7.5), was exposed to pH 5–6 while utilizing acetic acid for 7 months. This laboratory adapted anaerobic granular sludge when fed with CW showed 30% higher methane generation under batch conditions compared to non-acclimatized granular sludge under the same conditions (pH 5–6). Higher percentage of hydrogenotrophic methanogens (mostly Methanolinea) and increase of Clostridium at the anaerobic granular sludge exposed to pH 5–6 compared to initial granular sludge was found. Propionic acid was the reaction limiting step for granular sludge under pH 5–6. Anaerobic digestion at moderately low pH required 68% less NaOH (50 %v/v) per m3 of CW however it can theoretically produce 53% less kWh per day compared to digestion at neutral pH. • The Internal Circulation reactor had 80% COD removal from dairy wastewater treatment. • At IC 0.17 kg NaOH per m3 of influent was required to maintain the pH neutral. • Methanolinea sp were increased when granular sludge treated cheese whey at pH 5-6. • Propionic acid is the reaction limiting step for granular sludge under these conditions. • Acclimatized granular sludge (pH 5–6) requires 68% less NaOH per m3 of cheese whey. [ABSTRACT FROM AUTHOR]

This present study focuses on the evaluation of the effectiveness and the feasibility of a combined treatment between the electrocoagulation (EC) and the adsorption on an activated carbon in grains (GAC) in a continuous mode. The peculiarity of this work is that the experiments are conducted with real wastewater from an industrial dairy. This combined treatment first required an optimization of the EC followed by an adsorption. For each of these techniques, different influential operating parameters such as the current density, the reaction time, the GAC dose, the initial turbidity of water ... etc., have been studied. The Turbidity and the COD have been continuously analyzed, while the phosphorus, the BOD5, TSS, nitrogen and the grease have been punctually analyzed, and this happened before and after the water treatment. The EC adsorption coupling results have shown that the addition of an appropriate dose of GAC (2 gL−1) in a separate column, increases the effectiveness of treatment; more than 98 % of reduction for the COD, the BOD5, the turbidity and the greases. A mechanism explaining the phenomena which are involved in this combined treatment is proposed. On the basis of these results of efficiency, speed, low operational cost (~ 3 $m−3 of the treated water), and in comparison with the EC used alone, the EC coupling/the adsorption GAC, could be recommended as a treatment of separation for waters at a high load in organic pollutants. [ABSTRACT FROM AUTHOR]

In order to meet the land use requirements of the treated wastewater from high density polyethylene (HDPE) membrane-enclosed anaerobic lagoons, the physical and chemical properties of the wastewater in an HDPE membrane-enclosed anaerobic lagoon were measured. The total nitrogen content (TN) in wastewater treated in membrane-enclosed anaerobic lagoons is 3165 and 1510 mg/L in winter and summer respectively. The wastewater can be used as liquid organic fertilizer, partly replacing chemical fertilizer. The safety dosage of the wastewater was 21.48 t/ha for rice and 9.54 t/ha for corn, respectively. Meanwhile, the wastewater has the characteristics of high salt (conductivity>16.0 mS/cm) and high organic matter content (COD>16,900 mg/kg). Therefore, the potential negative effects of the wastewater on soil salinity and pH should be assessed. 16S rRNA was used to investigate the bacterial population structure and assess potential biological risks of land use of the wastewater. The wastewater from lagoon has the least and the most bacterial abundance in summer and winter, respectively. The bacterial diversity of wastewater samples from lagoon is the most. 21 and 24 phyla were detected in winter and summer samples respectively. Clostridium is the absolute dominant bacteria in the summer water samples and the absolute dominant bacteria is Trichococcus in winter water samples. Several animal and plant bacterial pathogens such as Campylobacter , Corynebacterium , Facklamia and Erysipelothrix can be detected in the wastewater samples. More than 70% of pathogenic bacteria such as Campylobacter , Facklamia , Erysipelothrix and Acholeplasma can be removed by lagoon in summer, but only about 99% of Corynebacterium is still in the lagoon (XYH). While more than 60% of Corynebacterium , Facklamia and Erysipelothrix are not removed in winter. So the biological risk of land use of anaerobic pond wastewater needs to be considered. [Display omitted] • The treated wastewater can be land used as liquid organic fertilizer. • Caution should be exercised due to the effect of salt and low pH on soil and crops. • Recommended amount for paddy and corn field is 21.48 and 9.54 t/hm2, respectively. • Attention should be paid to biological safety of the treated wastewater. [ABSTRACT FROM AUTHOR]

Facilitating anaerobic degradation of long-chain fatty acids (LCFA) is key for tapping the high methane production potential of the fats, oil and grease (FOG) content of dairy wastewaters. In this study, the feasibility of using high-rate granular sludge reactors for the treatment of mixed LCFA-containing synthetic dairy wastewater (SDW) was assessed at 20 °C. The effects of the LCFA concentration (33–45% of COD) and organic loading rates (2–3 gCOD/L·d) were determined using three parallel expanded granular sludge bed reactors. For the first time, long term anaerobic treatment of LCFA-containing feed at 20 °C was shown to be feasible and was linked to the microbial community dynamics in high-rate reactors. During a two-month operation, a soluble COD removal of 84–91% and COD to methane conversion of 44–51% was obtained. However, granular sludge flotation and washout occurred after two months in all reactors without volatile fatty acids (VFA) accumulation, emphasizing the need for sludge retention for long-term granular sludge reactor operation with LCFA-containing feed at low ambient temperatures. The temporal shifts in microbial community structure were studied in the high-rate treatment of SDW, and the process disturbances (elevated LCFA loading, LCFA accumulation, and batch operation) were found to decrease the microbial community diversity. The relative abundance of Methanosaeta increased with higher LCFA accumulation in the settled and flotation layer granules in the three reactors, therefore, acetoclastic methanogenesis was found to be crucial for the high-rate treatment of SDW at 20 °C. This study provides an initial understanding of the continuous anaerobic treatment of LCFA-containing industrial wastewaters at low ambient temperatures. Unlabelled Image • Mixed-LCFA was anaerobically treated in EGSB reactors at 20 °C. • 84–91% soluble COD removal and 50% methane conversion were achieved. • Granular flotation and washout occurred when feeding EGSB with LCFA. • Ratio of acetoclastic to hydrogenotrophic methanogens increased with LCFA loading. [ABSTRACT FROM AUTHOR]