Dairy Industry Wastewater Research Articles

Environmental and Agronomical Aspects of Sludge Produced from Tannin-Based Coagulants in Dairy Industry Wastewater Treatment

A study was carried out of the environmental and agronomic features of the sludge generated by a dissolved air flotation process applying a tannin-based coagulant in a dairy factory. First, the chemical and physical characteristics of the sludge were examined. Subsequently, a solubilization test was performed to evaluate the potential of groundwater contamination after the application of sludge on soil. The data obtained were compared to the United States Environmental Protection Agency (US-EPA) criteria for evaluation and classification of solid residues for land application. The results show that the studied sludge is a non-hazardous waste, and all evaluated parameters are lower than the maximum reference values according to international criteria. Based on the set of parameters which were evaluated, no organic pollutants were found. Additionally, the agronomic characterization shows good potential for agricultural purposes. However, in the solubilization test, chemicals such as phenols, cyanide, nitrate and fluoride were solubilized from the studied residue. As a result, the water showed concentrations above the limits required by the international criteria for drinking water established by US-EPA and World Health Organization. In conclusion, although tannin-based coagulants produce sludge with the potential for agronomic applications, some limits have to be considered to avoid environmental impacts.

Optimization of nutrient stress using C. pyrenoidosa for lipid and biodiesel production in integration with remediation in dairy industry wastewater using response surface methodology.

The present study illustrates optimization and synergetic potential of alga Chlorella pyrenoidosa for lipid production and remediation of Dairy industry wastewater (DIWW) through response surface methodology (RSM). Maximum lipid productivity of 34.41% was obtained under 50% DIWW supplemented with 0mgL-1 nitrate (NO3-), and 50mgL-1 phosphate (PO4-3). While maximum biomass productivity (1.54gL-1) was obtained with 50% DIWW supplemented with 100mgL-1 NO3-, and 50mgL-1, PO4-3. Maximum removal of COD (43.47%), NO3- (99.80%) and PO4-3 (98.24%) was achieved with 8th run (75% DIWW, 150mgL-1 NO3-, 75mgL-1 PO4-3), 15th run (50% DIWW, 0mgL-1 NO3-, 50mgL-1, PO4- 3) followed by 1st run (25% DIWW, 50mgL-1 NO3-, and 25mgL-1, PO4-3), respectively. Lipid (bio-oil) obtained from 15th run of experiment was converted in biodiesel through base catalyze transesterification process. Fatty acid methyl ester (FAME) analysis of biodiesel confirmed the presence of major fatty acids in C. pyrenoidosa grown in DIWW were C11:0, C14:0, C16:0, C16:1, C18:1 and C18:2. Results of study clearly demonstrate enhanced growth and lipid accumulation by C. pyrenoidosa in surplus PO4-3 and limitation of NO3- sources with DIWW and its suitability as potential alternative for commercial utilization.

Degradation kinetics of organic matter in dairy industry wastewater by flotation/ozonation processes

This study evaluated the adjustment of four kinetic models and their respective parameters on data of dairy wastewater treatment by the physico-chemical process of flotation and ozonation. The experiment was implemented during the year 2014, with all the tests in triplicate. The treatments were carried out at different pH levels (3.6, 7.0 and 10.4), and flotation/ozonation was catalyzed by manganese (Mn2+) in neutral level (pH 7.0). Best removal efficiencies for chemical oxygen demand (COD) were obtained in acidic medium, with removals greater than 75% after 20 min of treatment. There was no significant difference with regards to addition of Mn2+on COD removal by the physico-chemical process. The kinetic models that best fit to the experimental data, for all treatments, were the asymptotic (residual) model and that of Chan and Chu. Treatment in acidic medium showed the highest values of the kinetic parameters for the adjusted model, obtaining a k coefficient equal to 0.2394 min-1for the asymptotic model and kinetic coefficient 1/ρ of 0.4816 min-1for the Chan and Chu model, both presenting a determination coefficient greater than 99%.

Hydraulic Retention Time Influence on Improving Flocculation in the Activated Sludge Processes Through Polyelectrolytes

Hydraulic retention time (HRT) influence improving sludge flocculation with adding the polyelectrolytes (non-ionic, anionic, and cationic) was studied on an activated sludge (AS) system fed with synthetic domestic wastewater (SDW), dairy industry wastewater (DIW), and caramel industry wastewater (CIW). The sludge volumetric index, food/microorganism ratio (F/M), and mixed liquor volatile suspended solids at different HRTs (6, 8 and 10 h) were monitored on an experimental model. Results showed that both SDW and IW had the best sludge flocculation conditions at 8 h and 100 mL of non-ionic polyelectrolyte (0.2 mg L−1). In addition, this phenomenon reached the organic matter removal efficiencies of 95.9, 95.7, and 94.2% for SDW, DIW, and CIW, respectively. Therefore, optimum HRT increased the organic matter removal efficiencies by 10%, sludge concentration by 37% (22–55%), and F/M ratio by 70%. Moreover, the polyelectrolytes used in AS improved the sludge flocculation by 2.9 times.

Design study of an AnSBBR for hydrogen production by co-digestion of whey with glycerin: Interaction effects of organic load, cycle time and feed strategy

An anaerobic sequencing batch biofilm reactor (AnSBBR) treating a mixture of dairy industry wastewater and biodiesel production wastewater (co-digestion of whey with glycerin) was applied to hydrogen production. The influence of fed-batch and batch mode, cycle time and interactions effects between influent concentration and cycle time (2, 3 and 4 h) over the organic loading rate were assessed in order to obtain a sensitivity analysis for important operational variables to the reactor. It was possible to find an optimal cycle time of 3 h with an influent concentration of 7000 mgCOD L−1 (molar productivity 129.0 molH2 m−3 d−1 and yield 5.4 molH2 kgCOD−1). Reactor operation in fed-batch mode allowed higher hydrogen production rates. Increasing the influent concentration (with a constant cycle time) was better for the hydrogen production process than decreasing the cycle length (with a constant influent concentration), which means that these two parameters have different weights in the organic loading rate. The best operational conditions produce hydrogen via acetic, butyric and valeric acids similarly. The system is able to produce 1.3 kJ per gram of COD applied.

Perspective of using biogas in Serbia in European context

ABSTRACTThe aim of this study is to analyze the possibility of achieving the goal related to share of biogas energy in the final energy consumption in Republic of Serbia up to 2030 which refers to reach of 2% of electricity produced from biogas, 1% of the final energy consumption in transport produced from biogas, and 1% of the final heat energy consumption from biogas in accordance with the recommendations of the European Biomass Association (AEBIOM). The analysis was performed on the basis of estimated biogas potential, where biogas was produced from energy crops dedicated to energy production, animal husbandry, municipal solid waste, waste from the meat industry and dairy industry wastewater as well as Serbian energy development strategy until 2030.

Sequential hydrogen and methane production with simultaneous treatment of dairy industry wastewater: Bioenergy profit approach

A sequential study for hydrogen and methane production with pollutants reduction from dairy industry wastewater (DIWW) was conducted using bacterial strain of Enterobacter aerogens and methanogenic bacteria of cow dung. Among the different selected concentrations of DIWW viz: 25%, 50%, 75% and 100%, the 75% concentration depicted the best feasibility for biomass growth rate (0.21 h−1) as well as hydrogen (105 ml H2/g-Chemical Oxygen Demand (COD) and 0.562 L-H2 L−1 DIWW) and methane (190 CH4 ml/g-COD and 0.59 L CH4 L−1-FDIWW) production with the selected substrate. Experimental results were tested with various kinetic models viz. (Monod, Moser, Hanes–woolf and Eadie–Hofestee) to observe substrate utilization and growth pattern of bacteria. Hanes equation (R2 = 0.95) was the best fitted model observed in the present study. Economic Assessment of produced energy (0.22$/m3 DIWW and 0.336$/m3-FDIWW) illustrates the selected pathway has the viability of the system for treatment simultaneous with bioenergy production.

Evaluation of a membrane bioreactor on dairy wastewater treatment and reuse in Uruguay

Eutrophication episodes have been recently observed in the Santa Lucia river basin (SLRB) in Uruguay, the main drinking water source for approximately 60% of the Uruguayan population. The local environmental authorities have been strengthening the discharge standards for that particular river basin. There are several industries currently discharging their wastewater directly into the SLRB; some of these industries are required to upgrade their current wastewater treatment systems to comply with the new regulations. This study evaluated the performance of a membrane bioreactor (MBR) on dairy wastewater as a potential treatment technology for fulfilling the new discharge standards. A pilot MBR was placed at the dairy industry wastewater treatment system at two different locations: (i) receiving the wastewater from the industrial process after passing through a grease removal pond (high load stream); and (ii) receiving the wastewater after passing through the grease removal pond and an anaerobic pond (low load stream). The pilot MBR was operated at the following conditions for approximately four months: total sludge retention, hydraulic retention time (HRT) of 25 h, an average influent flow rate of 1.3 m3 day−1, and at two different average chemical oxygen demand (COD) influent concentrations: 1300 mg L−1 (high load stream) and 385 mg L−1 (low load stream). The average reported removal efficiencies on COD, biological oxygen demand (BOD), and ammonium (NH4-N) were 94.1, 98.1, and 99.6%, respectively. In addition, it was observed that for a COD/N ratio above 10, total nitrogen (TN) and total phosphorous (TP) were well removed with average removal efficiencies of 93.1 and 91.0%, respectively. The MBR effluent met the new Uruguayan standards for discharging into the SLRB, and it can be further considered for water reuse at the industrial process. Moreover, a financial feasibility study was carried out for the implementation of a full scale MBR at the existing dairy facility. The results of the feasibility study suggested to accept the investment for the implementation of the MBR technology at the dairy industry. The results of the feasibility analysis considered the high impact of penalties and fines imposed by the local government to the industry when not complying with the effluent discharge standards, as well as the critical situation regarding eutrophication of the SLRB while being the most important source for drinking water in Uruguay.

Microalgal biomass generation by phycoremediation of dairy industry wastewater: An integrated approach towards sustainable biofuel production

Dairy wastewater collected from local dairy industry was used as a growth media (without any pre-treatment) for the cultivation of microalgae Acutodesmus dimorphus. The level of COD reduced over 90% (from 2593.33±277.37 to 215±7.07mg/L) after 4days of cultivation; whereas, ammoniacal nitrogen was consumed completely (277.4±10.75mg/L) after 6days of cultivation. Dry biomass of 840 and 790mg/L was observed after 4 and 8days of cultivation, respectively, which is about 5–6 times more than that of BG-11 grown culture (149mg/L after 8days). This biomass contains around 25% lipid and 30% carbohydrate, which can be further converted into biodiesel and bioethanol, respectively. Theoretical calculations based on the recently reported conversion yield suggest that 1kg biomass of A. dimorphus might produce around 195g of biodiesel and 78g of bioethanol, which sums up to 273g of biofuels.

Dairy wastewater treatment using a novel low cost tubular ceramic membrane and membrane fouling mechanism using pore blocking models

This study investigated the potential application of a novel low cost tubular ceramic membrane in treating wastewater generated by a local dairy industry. The low cost tubular membrane ($0.5) with 0.309μm pore size, 53% porosity and 5.93×10−7m3/m2skPa water permeability was fabricated from natural clay materials by extrusion technique. The capability of the membrane for treating real dairy industry wastewater was tested in tangential mode of microfiltration operation at different applied pressure (207–414kPa) and cross flow rate (5.55×10−7–2.22×10−6m3/s). An increase in applied pressure and cross flow rate on the microfiltration process resulted in a decrease in percentage removal of chemical oxygen demand (COD). The novel membrane achieved a maximum reduction in COD up to 91% (135mg/L) in the permeate stream with a flux of 2.59×10−6m3/m2s, which is well within the permissible limit for wastewater discharge into the environment. These investigations affirmed the potential suitability of the membrane in dairy wastewater treatment to attain acceptable limit (<200mg/L) of the permeate stream. Consequently, the membrane fouling mechanism was examined using conventional pore blocking models, viz. complete, standard, intermediate pore blocking and cake filtration model. The experimental results were well described by the cake filtration model. Additionally, the potential of the novel membrane was compared with other membranes reported in the literature for dairy wastewater treatment application.

Continuous flow electrocoagulation in the treatment of wastewater from dairy industries.

Dairy industry wastewater contains high levels of organic matter, consisting mainly of fat, protein and products of their partial microbial decomposition. In the present study, the use of continuous electrocoagulation is proposed for the primary treatment of dairy wastewater. The electrochemical treatment was carried out in a continuous flow cell with aluminum electrodes. The influence of the voltage, the distance between the electrodes and the hydraulic residence time (HRT) on the process performance was assessed, by measuring the removal of color, turbidity, total organic carbon (TOC) and chemical oxygen demand (COD). The optimum voltage, distance between the electrodes and HRT were 10 V, 1 cm and 90 min, respectively, yielding a current density of 13.3 A.m(-2). Under these conditions, removal of color, turbidity, TOC and COD were 94%, 93%, 65% and 69%, respectively, after a steady state was reached in the continuous flow reactor.

Hierarchical prioritization of innovative treatment systems for sustainable dairy wastewater management

Multiple criteria decision making is an effective approach that can be successfully used for revealing eco-innovative solutions in industrial wastewater treatment by prioritizing various promising technologies. Besides, eligible researches on emerging membrane processes viz., forward osmosis and membrane distillation are gaining widespread interest in scientific communities focused on reclamation, recovery and reuse of industrial wastewaters. In this study, the preferability of four innovative systems compared to a traditional system was hierarchically prioritized for environmentally benign treatment and utilization of dairy industry wastewater using the most common tool in multi-criteria decision making analysis, analytical hierarchy process. The analyses were attributed to the preferences classified with regard to the technical, economic and environmental aspects of the alternatives. Despite the existence of both greatest importance of energy consumption and higher energy requirements of novel solutions, major prominent features to be provided by real-scale applications of innovative systems were determined as more valuable multiple outcomes in environmental protection and economic profit. The sensitivity analysis to evaluate how the variations in the predefined weights of attributes influence the preference priorities indicated that the decision prioritization analysis on the novel technology selection was sufficiently sensitive to all the main evaluation criteria. This study proved that novel membrane technologies have more preferable features in dairy wastewater treatment by further whey utilization and waste minimization and more effective industrial water reuse, especially in case of waste heat usage in membrane distillation. Finally, sustainable dairy wastewater management in a more desirable manner than now could be accomplished by means of technically highly efficient, economically cost-effective and environmentally eco-innovative achievements.

Study of fat compost from dairy industry wastewater as a new substrate for pepper (Capsicum annuum L.) crop

The aim of this study was to analyze the impact of different doses of compost obtained from fats waste of dairy industry mixed with commercial peat-based substrate and with soil on pepper plants development. Furthermore, this investigation attempted to determine the effects of these mixtures on germination and composition of pepper fruits. Fat compost (FC) was obtained by aerobic composting from dairy industry wastewaters mixed with wood chips and green grass. FC extract resulted free of phytotoxicity for seed germination, obtained 99.71% the relative seed germination and 74.10% of germination index. Different growing media were prepared by mixing 0, 10, 20 and 40% of FC with commercial substrate (CS) or Soil in two different experiments. Results showed that the application of FC on CS and Soil respectively, increased plant dry matter. On pepper seedling FC 40 achieves 250mg plant−1 DM. Moreover, higher doses of FC improved yield and several characteristics of fruit as dry matter, diameter and concentrations of some carotenoids. The incorporation of FC did not increase the heavy metals concentration of pepper fruit. At leaves, the highest concentrations of N were reached shown on treatment with FC (Soil: 1.46%, FC 10: 1.92%, FC 20: 2.00%, FC 40: 2.09%). Application of FC for germination and development of pepper plants improved the seedlings, fruit yield and quality.

Heavy metal ions adsorption from dairy industrial wastewater using activated carbon from milk bush kernel shell

Activated carbons (MBK400 and MBK600), produced from milk bush kernel shells, were carbonized at 400 and 600°C, respectively, activated with H3PO4, and subsequently, employed to remove heavy metals (cadmium, lead, nickel, zinc, iron, and copper) in dairy industrial wastewater (DIWW). Effects of doses (1.0–3.0 g/L) and contact time (5–25 min) at constant agitation (120 rpm) on removal efficiencies and adsorption capacities of the agricultural precursors were investigated. Four types of Langmuir isotherm model were used to fit the adsorption of the heavy metals. The pH of the treated DIWW increased from 6.1 to a range of 6.7–6.9 and 6.8–6.9 with MBK400 and MBK600, respectively, while, there were slight increase in the conductivity of the treated DIWW, except with 3.0g of MBK400, which reduced the conductivity from 377 to 345 µS/cm. The maximum percentage of cadmium, iron, copper, lead, zinc and nickel removal were 90, 80, 91.7, 91.6, 87.18, and 73.62% with 2.0 g/L MBK400, 1.0 g/L MBK400, 3.0 g/L MBK600, 2.0 g/L MBK600, 3.0 g/L MBK600 and 1.0 g/L MBK600, respectively. The removal of lead ranked the highest, consistently, for all the doses of MBK400 and MBK600 used. The Langmuir Type-1 was the most suitable linearized Langmuir isotherm that described the adsorption of the heavy metals in the DIWW, based on coefficient of determination (R2). The adsorbents developed are suitable for the removal heavy metals, particularly lead, in a typical DIWW.

&lt;b&gt;Efficiency and operating cost of electrocoagulation system applied to the treatment of dairy industry wastewater

The objective of this study was to apply the technique of electrocoagulation (EC) in the treatment of dairy industry wastewater, using a system of bench. It was used a source of 10 amps and an electrode of iron containing six plates of 14x6 cm. Were made variation of pH (4.5 to 6), intensity of electric current (1 to 2A) and time of electrolysis (30 to 60 min.). The efficiency of the treatment was confirmed by analysis of turbidity, color and COD. The reduction of turbidity was greater than 98%, reaching a record 99.98%. The largest reduction in color was 94.90% and 11 of the 27 tests the efficiency was greater than 90%. The greatest reduction of COD was 96.36%. The treatment proved to be more efficient at pH 4.5, time 60 min. and current 1.5A. The estimated cost of operation was US$ 1.04 m 3 which demonstrates the viability of treatment of dairy industry wastewater.

Electrocoagulation Process Coupled with Advance Oxidation Techniques to Treatment of Dairy Industry Wastewater

Electrocoagulation Process Coupled with Advance Oxidation Techniques to Treatment of Dairy Industry Wastewater

The Effects of Temperature on the Performance of Anaerobic Sequencing Batch Reactor in the Treatment of Synthetic Dairy Wastewater

raw wastewater in the primary tank was heated to the desirable temperature and then three more heaters continuously produce the heat in the reactor to operate system at the constant operating temperature in each run. Data were analyzed by SPSS 16through Pearson's correlation coefficient to analyze the association between these parameters. Results: The maximum COD removal rate was 89.7% at the organic loading of 4.5 g/L per day in a 24-hour cycle condition with reaction time of 21 hours and 30 minutes. The maximum biochemical oxygen demand (BOD5) removal rate was 91% and occurred at the first run. The amount of COD removal efficiency was higher at the first run in comparison to the third cycle (27.5%). BOD5 removal efficiency decreased up to 24.4% due to the drop of temperature in the reactor. Pearson correlation analysis showed a significant association between the temperature and the removal efficiencies (P < 0.01). Conclusions: The results of this study indicated that any decrease in the temperature caused reduction in system efficiency of removing BOD5 and COD. Temperature of 35°C is optimal for the removal of high organic load wastewater. ASBR can be used as an effective tool to treat dairy industry wastewater.

Evaluation of dairy industry wastewater treatment and simultaneous bioelectricity generation in a catalyst-less and mediator-less membrane microbial fuel cell

Increased human activity and consumption of natural energy resources have led to decline in fossil fuel. These current methods of energy production are not compatible with the environment. In this study catalyst-less and mediator-less membrane microbial fuel cell (CAML-MMFC) represents a new method for simultaneous dairy industry wastewater treatment and bioelectricity generation. The CAML-MMFC used was designed as two chambered that included an anaerobic anode and aerobic cathode compartment and was separated from each other by a proton exchange membrane. The anode and cathode electrodes were made from graphite plate. Current intensity, power density and voltage produced from wastewater as fuel were measured and the effluent from the anode compartment was examined to evaluate pollutant decrease. The maximum current intensity and power density produced were respectively 3.74mA and 621.13mW/m2 on the anode surface, at OLR equal to 53.22kgCOD/m3d and at the external resistance of 1kΩ. The maximum voltage produced was 0.856V at OLR equal to 53.22kgCOD/m3d and at temperature 35oC. The maximum coulombic efficiency of 37.16% was achieved at OLR equal to 17.74kgCOD/m3d. The HRT was examined as a factor influencing the power generation and when it was 5 day, maximum voltage and power density were obtained. The maximum removal efficiency of COD, BOD5, NH3, NH4+, dissolved phosphorus, phosphorus in suspended solids, SO42−, TSS, and VSS was respectively achieved at 90.46%, 81.72%, 73.22%, 69.43%, 31.18%, 72.45%, 39.43%, 70.17% and 64.6%. The results showed that generating bioelectricity and dairy industry wastewater treatment by CAML-MMFC are a good alternative for producing energy and treating wastewater at the same time.

Treatment of dairy industry wastewater by oxygen injection: performance and outlay parameters from the full scale implementation

This work presents the application of a new system for wastewater treatment in the food industry, which is based in the injection of pure oxygen in the homogenization tank of a traditional physicochemical treatment. This system operates stably under a wide variety of both input chemical oxygen demand (COD) and total suspended solids (TSS). Compared with the previous physicochemical system, it has been proved that the new one is more efficient and implies important economic savings for the dairy. Compared with a traditional anaerobic treatment, it has been shown that the oxygen injection system avoids the relatively high costs associated to the initial investment and operating costs and is environmentally friendlier. In this work it is shown that oxygen injection may be an interesting option for the dairy industry wastewater treatment.

A review on fermentative hydrogen production from dairy industry wastewater

AbstractHydrogen (H2) is one of the most promising alternative fuel sources for satisfying future energy demand, and fermentative hydrogen production is advantageous over other processes. In recent decades, considerable research has been conducted on H2 production from carbohydrate‐rich materials since it is a cost‐effective approach and has the ability to generate intensive renewable energy from organic wastes. Dairy wastewater is a high volume industrial wastewater and with its immense carbohydrate content is an attractive candidate for sustainable fermentative H2 production. The present paper provides comprehensive evaluation of recent reports on fermentative H2 production from dairy wastewater. Important effective parameters and current bioreactor technologies for H2 production from dairy wastewater are discussed. © 2014 Society of Chemical Industry