Treatment Of Food Processing Wastewater Research Articles

Evaluation of Efficiently Removing Secondary Effluent Organic Matters (EfOM) by Al-Based Coagulant for Wastewater Recycling: A Case Study with an Industrial-Scale Food-Processing Wastewater Treatment Plant.

The reuse of wastewater has been identified as an important initiative for the sustainable development of the environment; thus, the removal of secondary effluent organic matter (EfOM) to ensure the safety of reused wastewater is the key step and a subject of extensive research. In this study, Al2(SO4)3 and anionic polyacrylamide were selected as coagulant and flocculant, respectively, for the treatment of secondary effluent from a food-processing industry wastewater treatment plant to meet the standard regulatory specifications for water reuse. In this process, the removal efficiencies of chemical oxygen demand (COD), components with UV254, and specific ultraviolet absorbance (SUVA) were 44.61%, 25.13%, and 9.13%, respectively, with an associated reduction in chroma and turbidity. The fluorescence intensities (Fmax) of two humic-like components were reduced during coagulation, and microbial humic-like components of EfOM had a better removal efficiency because of a higher Log Km value of 4.12. Fourier transform infrared spectroscopy showed that Al2(SO4)3 could remove the protein fraction of the soluble microbial products (SMP) of EfOM by forming a loose SMP protein complex with enhanced hydrophobicity. Furthermore, flocculation reduced the aromaticity of secondary effluent. The cost of the proposed secondary effluent treatment was 0.034 CNY t-1 %COD-1. These results demonstrate that the process is efficient and economically viable for EfOM removal to realize food-processing wastewater reuse.

Stryhnos potatorum and Pisum sativum as natural coagulant for meat food processing wastewater treatment: isotherm studies

ABSTRACT This study was to determine the flocculation performance of Stryhnos Potatorum (Nirmali seed) and Pisum Sativum (pea seed) as natural coagulants for treating meat food processing wastewater (MFPW). A lab-scale treatment tank was developed to evaluate the effectiveness of MFPW treatment.The flocculation process was evaluated in relation to adsorbent dosage (30–330 mg/L), pH (4–9) and mixing rate (100–350 rpm). Results showed that optimum dosage, pH and mixing rate for S. Potatorum were pH 8 with the dosage of 150 mg/L and 150 rpm mixing rate with the removal of turbidity, TSS, COD, O&G, and color are 91%, 97.6%, 58.4%, 79.9% and 84.3% respectively. Meanwhile, for P. Sativum, the optimum condition was observed at pH 8 with the dosage of 150 mg/L and 150 rpm mixing rate with the removal of turbidity, TSS, COD, O&G, and color 87.8%, 97.3%, 65.5%, 77.9% and 76.5% respectively. The Langmuir model was found to be the best fit (R2 > 0.95) for TSS, O&G and color removal from MFPW in both coagulants, compared to the Freundlich model for both natural coagulants. In contrast, the Freundlich isotherms were best described by the removal of turbidity (R2 = 0.97) and COD (R2 = 0.93) by using P. Sativum. The findings obtained showed that natural coagulants give an efficient treatment solution for improving MFPW quality.

Insights into the minimization of excess sludge production in micro-aerobic reactors coupled with a membrane bioreactor: Characteristics of extracellular polymeric substances

The production of excess sludge by the activated sludge system of wastewater treatment plants is a problem. In this study, the EPS characteristics on production and degradation were investigated in the real-scale food processing wastewater treatment system (i.e., a micro-aerobic reactor coupled with a membrane bioreactor (MAR-MBR)) with a treatment capacity of 150 t d−1, which could cater for the low production of excess sludge (i.e., 9 t·a−1; 76% moisture content). The total organic carbon concentrations in the different EPS fractions were in the following order: soluble EPS (S-EPS) < loosely bound EPS (LB-EPS) < tightly bound EPS (TB-EPS). Although the components (e.g., protein and humic acid-like substances) of each EPS fraction changed significantly throughout the MAR-MBR process owing to the low production of excess sludge, the degrees of change in S-EPS, LB-EPS, and TB-EPS were significantly different from the corresponding change in their relative molecular weights. Furthermore, the microbial community composition was beneficial for the release and degradation of EPS, and the regulation of gene functions via the MAR-MBR enhanced this process.

Dynamic anaerobic membrane bioreactor (DAnMBR) with phase separation for food processing wastewater treatment at mesophilic temperature: Characterization of cake layer

The treatment of high-strength wastewater using an anaerobic digester coupled with a dynamic membrane has gained significant interest of late due to its small footprint and low cost of supporting material for the membrane. Dynamic membrane fundamentally performs similarly to the conventional membranes by the cake layer deposited onto the supporting material with eventual fouling stage. The filtration performance is proportionally related to the cake layer development. Thus, the objective of this study is to characterize the cake layer affecting the filtration performance. A two-phase anaerobic digester with submerged 20-µm woven filter cloth as the supporting membrane (DAnMBR) was used in this study to treat food-processing wastewater. The organic loading rate of 5.0 g COD/L.day was fed into the DAnMBR, and the cake layer samples were taken at 14 days intervals until fouling occurred. The performance of the wastewater treatment and characteristics of the cake layer and bulk sludge were analyzed. It took a total of 35 days for the dynamic membrane to foul with a final flux of 2.5 L/m2·h and transmembrane pressure of 0.7 bar. The protein ratio to polysaccharide (PN/PS) of the extracellular polymeric substances increased significantly compared to soluble microbial product PN/PS ratio; thus, it is the main contributor to the membrane fouling. The thickness of the cake layer increased slightly from day 14 to 28 but sharply at the fouled stage (day 35), agreeing with the treatment performance. The concentrations of COD, BOD5, ammoniacal nitrogen, oil and grease, total suspended solids, and turbidity followed closely the inverse proportional trend of cake layer development. The size of the foulants that made up the cake layer resulted in micropore size dynamic membrane emanating the treatment performance of the DAnMBR is comparable to the conventional microfiltration AnMBR.

Advanced near-zero waste treatment of food processing wastewater with water, carbon, and nutrient recovery.

A near-zero waste treatment system for food processing wastewater was developed and studied. The wastewater was treated using an anaerobic membrane bioreactor (AnMBR), polished using an outdoor photobioreactor for microalgae cultivation (three species were studied), and excess sludge was treated using hydrothermal carbonization. The study was conducted under arid climate conditions for one year (four seasons). The AnMBR reduced the total organic carbon by 97%, which was mostly recovered as methane (~57%) and hydrochar (~4%). Microalgal biomass productivity in the AnMBR effluent ranged from 0.25 to 0.8g·L-1·day-1. Nitrogen (N) and phosphorous (P) uptake varied seasonally, from 18 to 45mg·L-1·day-1 and up to 5mg·L-1·day-1, respectively. N and P mass balance analysis demonstrated that the process was highly efficient in the recovery of nitrogen (~77%), and phosphorus (~91%). The performance of the microalgal culture changed among seasons because of climatic variation, as a result of variation in the wastewater chemistry, and possibly due to differences among the microalgal species. Effluent standards for irrigation use were met throughout the year and were achieved within two days in summer and 4.5days in winter. Overall, the study demonstrated a near-zero waste discharge system capable of producing high-quality effluent, achieving nutrient and carbon recovery into microalgae biomass, and energy production as biogas and hydrochar.

Performance of dynamic anaerobic membrane bioreactor (DAnMBR) with phase separation in treating high strength food processing wastewater

Food processing wastewater (FPW) contains high levels of oil and grease (O&G), especially from factories that produce fast food such as nuggets, sausages, and burger patties from beef, poultry, and fish. Therefore, the feasibility of replacing conventional membranes for the treatment of FPW with low-cost dynamic membranes (DM) as an alternative was investigated in this study. An anaerobic DM bioreactor (DAnMBR) was operated for 90 days to evaluate the treatment performance using real FPW under different organic loading rates (OLR) of 3.5, 5.0, 6.5, and 7.0 g COD (chemical oxygen demand)/Lday. Once the reactor had reached a steady-state of 90% COD removal, the feed to the reactor was supplemented incrementally with FPW from 10% to 90% as COD to allow the methanogenic bacteria to acclimate any potential inhibitory effects from its recalcitrant content. The bioreactor presented a stable performance at OLR 5.0 g COD/Lday with 97.5% removal of COD and reached 20 mg/L total suspended solids (TSS) discharge. A significant correlation between COD fractions removed via acidogenesis and methanogenesis with different OLR was found, indicating that the increase in treatment performance is beneficial to the methanogenic archaea activity. The methane gas production yield achieved a maximum of 0.40 L methane/g CODadded at OLR 3.5 and 5.0 g COD/Lday. The average permeate flux in these studies is around 60 L/m2h. The DM fouled after 57 days (at flux 27.16 L/m2h immediate drop to 2.16 L/m2h) when operated at 3.5 g COD/Lday. After it fouled, the membrane underwent physical cleaning, backwashed in-situ for 5 min, and reused again without any chemical cleaning. The improved filtration resistance is contributed by the occurrence of DM fouling induced by the soluble microbial products (SMP) and extracellular polymeric substances (EPS) release as well as the increased protein/carbohydrate (P/C) ratio in the mixed liquor.

Cultivation of aerobic granular sludge for the treatment of food-processing wastewater and the impact on membrane filtration properties.

A laboratory-scale sequencing batch reactor was operated for approximately 300 days, divided into four periods based on the feeding strategy, to develop stable aerobic granular sludge (AGS) while treating chocolate processing wastewater. Application of a prolonged mixed anaerobic feeding was not sufficient to develop AGS and reach stable reactor performance. Through the application of a partially non-mixed and a partially mixed feeding strategy, the reactor performance was increased and stable AGS formation was established characterized by low diluted sludge volume index (D)SVI DSVI10,30) values of 78 ± 27 mL·g-1 and 52 ± 17 mL·g-1, respectively, and a capillary suction time/mixed liquor suspended solids value of 0.9 sec·(g·L-1)-1. The membrane bioreactor (MBR) filtration tests showed a reduction of the fouling rate (FR) and an increase of the sustainable flux (SF0.5) for AGS compared to flocs treating the same industrial wastewater. The SF0.5 (FR > 0.5 mbar·min-1) for the flocs was 10 L·(m2·h)-1 while for AGS the SF0.5 is higher than 45 L·(m2·h)-1 because the FR did not exceed 0.1 mbar·min-1. Additionally, the AGS showed reduced irreversible fouling tendencies due to pore blocking. Our results underline the need for an increased substrate gradient during anaerobic feeding for the development and long-term maintenance of AGS under minimum wash-out conditions. The AGS-MBR filtration performance also shows strong advantages compared to a floccular MBR system due to a high increase of the SF0.5 and reduced reversible and irreversible fouling.

Experimental study and mathematical model of coagulation/sedimentation units for treatment of food processing wastewater

A model for coagulation/sedimentation was developed; based on experimental observations to investigate the removal of COD and TSS from the food processing wastewater. The experimental study was conducted using three coagulants: ferric chloride, ferrous sulfate, and aluminum sulfate. The wastewater samples were collected from an industrial food processing unit. Ferrous sulfate and aluminum sulfate are more efficient coagulants compared to ferric chloride. The removal efficiency of COD and TSS using alum were 79% and 92%, respectively. The removal efficiency of COD and TSS using FeCl3 were 73% and 93%, respectively. The removal efficiency of COD and TSS using ferrous sulfate were 79% and 93%, respectively.An empirical model was developed to evaluate the removal efficiency of the system. Different equations were developed for each coagulant. The model parameters were optimized using experimental observations. Statistical analysis indicated that the developed model can describe the experimental data accurately. The coefficient of determination (R2) values shows that the model can represent the experimental data with reasonable accuracy.

Application of Aurantiochytrium sp. L3W for food-processing wastewater treatment in combination with polyunsaturated fatty acids production for fish aquaculture

Thraustochytrids such as Aurantiochytrium are heterotrophic microorganisms that are known to produce valuable polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In this study, Aurantiochytrium sp. strain L3W was used to remove dissolved organic carbon (DOC) and dissolved nitrogen (DN) from bean-boiling (BB) and miso-processing (MP) wastewater and to simultaneously produce PUFAs. Strain L3W removed 52% of the DOC and 37% of the DN from sterilized BB wastewater and produced biomass that contained 137 mg/g of fatty acids (FAs), including 96.2 mg/g of DHA. Growth of strain L3W in sterilized MP wastewater resulted in the production of biomass containing 147.6 mg/g of FAs, including 97.8 mg/g of DHA, and removal of 47% of the DOC and 55% of the DN from the wastewater. The biomass of strain L3W was digestible by the enzymes extracted from the stomachs of rainbow trout. These results confirmed the potential for use of strain L3W to remove DOC and DN from food processing wastewater and to produce PUFAs. This study also provided the first evidence that the raw biomass of Aurantiochytrium sp. can be used as a fish feed additive.

Research on anaerobic treatment of food processing waste-water based on watershed water protection

Sweetmeat is one of the non-staple foods and a kind of classic non-staple food. It is of great practical significance to study the treatment of candied waste-water from factories along the river basin. Take the digestible sludge from the pipe of the dewatering workshop of the sewage treatment plant and anaerobic treat the high-concentration candie waste-water in the plastic bucket. The results showed that the suspended matter concentration of waste-water decreased to 8.04 g/L and the removal rate reached 22.1% after 60 h treatment. The absorbance of waste-water decreased from 0.835 to 0.598, the color removal rate reached 32.4%, and the chroma of waste-water decreased from 500 times to 80 times, reaching the “secondary standard” of “comprehensive sewage discharge standard (GB8978-1996)”.

Simple approach for the rapid estimation of BOD5 in food processing wastewater.

A simple approach was developed for the rapid and accurate estimation of 5-day biochemical oxygen demand (BOD5) in food processing wastewater. Immobilization of the natural microbial consortium that was collected from an aerobic compartment of a food processing wastewater treatment plant was simply performed by adhesion using a low-cost porous carrier. Pseudomonas aeruginosa, Bacillus cereus, and Streptomyces, whose salt-tolerance and ability to break down organic compounds have been widely reported, were found to be predominant. These microorganisms may cause an enhancement of the bioreactor response in the presence of sodium chloride. Consequently, a modified glucose-glutamic acid (GGA) calibration standard was proposed in which an appropriate amount of NaCl was added; this solution was found to be more effective in terms of accuracy and practicality than both conventional GGA and the synthetic wastewater recipe from the Organisation for Economic Cooperation and Development (OECD). The calibrated self-built packed-bed bioreactor exhibited good precision of 3% or less in predicting BOD5 in influent, which is similar to the performance of the most common commercial biochemical oxygen demand (BOD) bioreactors. There was a statistical agreement between the results obtained from this rapid BOD biosensor and the conventional methods, even when testing treated wastewater samples.

Potential of Food Processing Wastewater Treatment for Reuse

This study aimed to investigate the most effective treatment technique for the wastewater generated from food processing factory to be reused according to Egyptian standards. The discharged wastewater was highly polluted by organic load. As presented by average chemical oxygen demands (COD) value of 4950 mgO2L-1. Four treatment scenarios were investigated to select the most appropriate module for reuse of wastewater. Chemical coagulation-flocculation followed by adsorption onto granular activated carbon (GAC) achieved 84% of COD removal. The Fenton oxidation followed by adsorption onto GAC achieved COD removal of 91%.The Aerobic treatment followed by adsorption onto GAC reached to 92% COD removals. The quality of treated effluent using the previous modules was far less than the required values stated in Egyptian code for reuse in agriculture (Grade A). Integration of the studied different treatment modules in the form of sedimentation then chemical coagulation-flocculation followed by aerobic treatment then sandwich filter using adsorption/filtration (Sand/GAC/Sand) produced water quality complying with the Egyptian code for reuse in agriculture with COD removal of 99.8%.

Simultaneous bioenergy generation and carbon dioxide sequestration from food wastewater using algae microbial fuel cell

ABSTRACT Microbial fuel cell (MFC) provides a promising technology to handle two problems by decomposing organic waste and power generation which is economical and clean source of energy. However, use of platinum catalyst in the MFC is quite expensive and not economically suitable for real-time applications that needs to find an alternative. Hence, the main aim of the present research is to investigate the power generation and food processing wastewater treatment with two types of microalgae (Oscillatoria sp. and Scenedesmus sp.) as a biocathode in the MFC. The experimental results showed that the peak power density of 32.5 ± 0.5 and 28.5 ± 0.3 mW/m2 was obtained for Oscillatoria sp. and Scenedesmus sp., respectively. The MFC power generation was also investigated with respect to CO2 supply and light intensity, respectively. The results of this study indicated that the possibility of bioelectricity generation using algae as a biocatalyst for economic feasibility and allowing the development of energy efficient systems for wastewater treatment.

Food processing wastewater purification by microalgae cultivation associated with high value-added compounds production — A review

Abstract Microalgae have been considered as an efficient microorganism for wastewater treatment with simultaneously bioenergy and high value-added compounds production. However, the high energy cost associated with complicated biorefinery (e.g. microalgae cultivation, harvesting, drying, extraction, conversion, and purification) is a critical challenge that inhibits its large-scale application. Among different nutrition (e.g. carbon, nitrogen and phosphorous) sources, food processing wastewater is a relative safe and suitable one for microalgae cultivation due to its high organic content and low toxicity. In this review, the characteristic of different food wastewater is summarized and compared. The potential routes of value-added products (i.e. biofuel, pigment, polysaccharide, and amino acid) production along with wastewater purification are introduced. The existing challenges (e.g. biorefinery cost, efficiency and mechanism) of microalgal-based wastewater treatment are also discussed. The prospective of microalgae-based food processing wastewater treatment strategies (such as microalgae-bacteria consortium, poly-generation of bioenergy and value-added products) is forecasted. It can be observed that food wastewater treatment by microalgae could be a promising strategy to commercially realize waste source reduce, conversion and reutilization.

Antibacterial Properties of ZnO/Calcium Alginate Composite and Its Application in Wastewater Treatment.

In this study, the antibacterial activities of ZnO with various morphologies were evaluated. A possible mechanism of antibacterial activities of dumbbell like ZnO was proposed based on the microscopic studies of the interaction between bacterial and dumbbell like ZnO, and also based on the antibacterial activity of ZnO enveloped with semi permeable membrane. Monosodium glutamate (MSG) wastewater and soy sauce wastewater were treated by M. purpureus using ZnO/calcium alginate carrier. The attached and suspended biomass in MSG wastewater reached to 228 mg/g and 74 mg/g, while, the attached and suspended biomass in soy sauce wastewater was 130 mg/g and 66 mg/g, respectively. The levels of chemical oxide demand (COD), biological oxide demand (BOD5), SO4(2-) and NH3-N in the treated MSG wastewater were distinctive lower than those detected in the raw wastewater. This ZnO/calcium alginate carrier method could be utilized as an alternative to the traditional anaerobic/aerobic methods in the application of food processing wastewater treatment.

Settling of food-processing anaerobic sludge

This paper presents preliminary results of settling tests on anaerobic sludge from food-processing wastewater treatment, using 2, 4, and 8 L cylinders. A sedimentation model from the literature was applied to the sedimentation data. The specific settling velocities for the 2 and 4 L cylinders did not differ (t-test; P = 0.896), therefore the data were pooled. The specific settling velocity mean was nearly three times higher (P = 0.027) for the 8 L cylinder (21.03 × 10−4 ± 6.27 × 10−4 m/s) than the pooled smaller cylinder size (7.29 × 10−4 ± 2.32 × 10−4 m/s). Measurement challenges were encountered while working with the 8 L cylinder. Given that tests using a 1 L cylinder resulted in sludge compression, the results indicate that use of both 2 and 4 L cylinders is feasible for lab-scale measurement of sludge settling.

Application of Fenton’s Reaction for Food-processing Wastewater Treatment

AbstractDepending on the process type and raw materials involved, various types of wastewater are discharged from food industry. In the present study the feasibility of Fenton-based treatment, as a part of combined treatment schemes, to degrade high organic content, to eliminate suspended solids, and to improve the overall quality of food-processing plant wastewater was assessed. Fenton oxidation step used in treatment schemes improved significantly the quality of the effluent, enabling additional 62-79% and 53-69% reduction of chemical oxygen demand (COD) and dissolved organic carbon (DOC), respectively, when the H

Treatment of food processing wastewater in a full-scale jet biogas internal loop anaerobic fluidized bed reactor

A full-scale jet biogas internal loop anaerobic fluidized bed (JBILAFB) reactor, which requires low energy input and allows enhanced mass transfer, was constructed for the treatment of food processing wastewater. This reactor has an active volume of 798 m(3) and can treat 33.3 m(3) wastewater per hour. After pre-treating the raw wastewater by settling, oil separating and coagulation-air floating processes, the reactor was operated with a relatively shorter start-up time (55 days). Samples for the influent and effluent of the JBILAFB reactor were taken and analyzed daily for the whole process including both the start-up and stable running periods. When the volumetric COD loading fluctuated in the range of 1.6-5.6 kg COD m(-3) day(-1), the COD removal efficiency, the volatile fatty acid(VFA)/alkalinity ratio, the maximum biogas production and the content of CH(4) in total biogas of the reactor were found to be 80.1 ± 5%, 0.2-0.5, 348.5 m(3 )day(-1) and 94.5 ± 2.5%, respectively. Furthermore, the scanning electron microscope (SEM) results showed that anaerobic granular sludge and microorganism particles with biofilm coexisted in the reactor, and that the bacteria mainly in bacilli and cocci were observed as predominant species. All the data demonstrated that the enhanced mass transfer for gas, liquid and solid phases was achieved, and that the formation of microorganism granules and the removal of inhibitors increased the stability of the system.

Life Cycle Assessment of a Wastewater Treatment Plant Focused on Material and Energy Flows

Life cycle assessment (LCA) was applied to analyze a food-processing wastewater treatment plant and investigate the economic and environmental effects of the plant. With the long-term operational data of this plant, an inventory of relative inputs, e.g., flow rate, chemical oxygen demand (COD), and suspended solids, etc., and outputs of the plant, e.g., effluent COD and suspended solids, methane production, etc., was compiled. The potential environmental effects associated with those inputs and outputs were evaluated, and the results of the inventory analysis and impact assessment phases of the plant were interpreted. One feature of this study was the assessment of the treatment plant based on both energy and material flows. Another feature was the establishment of an assessment model with an integration of plant operating parameters, system recognition and grey relation. The analytical results are helpful for the design and operation of wastewater treatment plants.

The use constructed wetlands with horizontal sub-surface flow for various types of wastewater

Constructed wetlands with horizontal sub-surface flow (HF CWs) have been used for wastewater treatment for more than 30 years. Most HF CWs have been designed to treat municipal or domestic wastewater. Nowadays, municipal HF CWs focus not only on common pollutants but also on special parameters such as pharmaceuticals, endocrine disruptive chemicals or linear alkylbenzensulfonates (LAS). At present, HF CWs are used to treat many other types of wastewater. Industrial applications include wastewaters from oil refineries, chemical factories, pulp and paper production, tannery and textile industries, abattoir, distillery and winery industries. In particular, the use of HF CWs is becoming very common for treatment of food-processing wastewaters (e.g., production and processing of milk, cheese, potatoes, sugar). HF constructed wetlands are also successfully used to treat wastewaters from agriculture (e.g., pig and dairy farms, fish farm effluents) and various runoff waters (agriculture, airports, highway, greenhouses, plant nurseries). HF CWs have also effectively been used to treat landfill leachate. Besides the use as a single unit, HF CWs are also used in combination with other types of constructed wetlands in hybrid systems.