Oil Grease Research Articles

Current-Voltage-Friction Characteristics of Grease in Electromechanically Loaded Sliding Contacts

Abstract Electromechanically loaded contacts which have relative motion between the contacting parts experience severe damage compared to mechanical-loaded contacts. Such electromechanical environment occurs in the bearings of traction motors through which different types of currents flow, due to the usage of electronic speed control devices. The passage of current through the contact depends on the voltage potential developed across the contact. Grease is frequently used as a lubricant, and degradation and evaporation of lubricant due to the joule heating effect is a concern in the electromechanical contacts. In this study, the current-voltage-friction characteristics of lithium mineral oil grease are reported using a ball-on-disk configuration under combined electrical and mechanical loading. The characteristics indicated a transition of the lubricated contact from a non-conducting state to a conducting state with an increase in applied voltage. Two critical voltages are identified: one where the friction is observed to rise and the other is where the current flow rapidly increases leading to accelerated damage to the lubricant by inducing a significantly high temperature. The study helps in identifying permissible voltage levels to operate bearings safely from the perspective of grease lubricant using simplified ball-on-disk simulated experiments.

Ecological risk assessment of oil & grease (OG) and heavy metals in the surface water of Naf River, Bangladesh

This study aims to fill the gap in our understanding of the distribution and ecological risk of oil and grease (OG) and toxic heavy metals in the surface water of the Naf River, a major transportation route connecting Teknaf to Saint Martin's Island in Bangladesh. Altogether, 6 sampling stations in this river were assessed for OG and heavy metal pollution, revealing the presence of both at each station. The OG concentration is found ranging from 3.6 to 23.6 mg/L and the average concentration is 8.13 mg/L. On the other hand, the contamination factor (Cf) of the toxic heavy metals follows the descending order of Pb (63.97) > Cd (23.94) > Mn (0.94) > Ni (0.64) > Zn (0.22) > Cr (0.09) > Cu (0.04) > As (0.04) in the water samples. Heavy metal pollution index (HPI), Heavy metal evaluation index (HEI), and Nemerow pollution index (PN) indicate that the surface water of the study area includes high levels of pollution category due to the elevated levels of Pb, Cd, and Ni concentrations. The mean values of the single factor pollution index (Pi) for Pi(Pb), Pi(Cd) and Pi(Ni) are found 45.69, 39.41, and 6.43, which exceed the threshold limit. The ecological risk index indicates that around 25 % of the total heavy metals show a very high ecological risk and 75 % exhibit a lower ecological risk. Notably, within the very high ecological risk, Cd is responsible for 53 % of this risk, while Pb contributes the remaining 47 %. Increased OG and heavy metal concentrations in the Naf River are likely due to human activities like waste discharge from municipalities, solar power plants, pesticide use, and fishing trawlers. This research offers insights into the current state of the Naf River and guides policymakers toward more effective initiatives.

Pemanfaatan Air Limbah Domestik PT. X Kota Surabaya sebagai Penyiraman Ruang Terbuka Hijau

PT. X’s activities, such as the consumption of clean water by workers, visitors, and building maintenance produce domestic liquid waste in the form of grey water. Domestic liquid waste originating form PT. X is used for watering the company’s green open space, that has an area of 2384,4 . The water treatment used is anaerobic and aerobic biofilter. The volume of liquid waste grey water is 70 of the liquid waste produced at 4,09/day, sp the water utilization effieciency is 70. The resulting domestic liquid waste contains the pollutant parameters BOD5, COD, TSS, -N, oil grease, and Total Coliform, so processing by WWTP is required to be below quality standards. The processing units used consist of an interceptor tank, equalization tank, initial settling tank, anaerobic, aerobic, sedimentation, and efflluent tank. After processing and fulfil the quality standards, which has been set, the resulting efflulent is used for at a dose of 0,002 m3/m2/day with a watering frequency of 2 times a day.

Research on Analysis and Suppression Methods of the Bearing Current for Electric Vehicle Motor Driven by SiC Inverter

The silicon carbide (SiC) inverter brings great advantages to the motor drive systems of new energy vehicles; however, severe challenges to the bearings also happen. The high dc bus voltage and switching frequency of SiC inverter can increase the discharge frequency and energy when the bearing grease film collapses. As a result, the bearing suffers severe electric corrosion, and the service life of the motor drive system can be shortened. In this paper, the characteristics of common-mode voltage and bearing voltage are analyzed, firstly under space vector pulse width modulation (SVPWM). After that, the common-mode equivalent circuit model of the motor drive system is established. The frequency characteristics of bearing voltage are revealed, and the safe working area is determined. Then, the frequency characteristics of bearing voltage and current are verified based on IGBT and SiC inverters in experiments. After that, by designing a common-mode filter, the bearing voltage and current are significantly attenuated. Furthermore, the active zero state PWM (AZSPWM) is adopted to reduce the common-mode voltage from the inverter. At the same time, combined with the common-mode filter, the bearing voltage and current are further reduced. The experimental results show that the switching frequency has a decisive effect on the amplitude of bearing voltage and current. The bearing voltage can be attenuated to around half of the reference bearing voltage by using the common-mode filter and AZSPWM strategy, respectively. The combination of the common-mode filter and AZSPWM strategy can reduce the bearing voltage to around one-fourth of the reference bearing voltage, which can effectively reduce the breakdown time and discharge energy of the grease oil film.

STUDY OF COMMUNAL BASIUNI IMRAN ISLAMIC BOARDING SCHOOL WASTEWATER TREATMENT PLANT (WWTP) IN SAMBAS REGENCY

Islamic Boarding School has a treatment capacity of 33 m3 and an area of 24 m2. Based on the results of initial wastewater quality tests on communal WWTP, the TSS, COD, and BOD parameters are above the quality standard threshold based on the Wastewater Quality Standard of the Minister of Environment Regulation Number 68 of 2016. This evaluation aims to determine the processing efficiency of communal WWTP and evaluate the processing unit in communal WWTP as well as alternative improvements that effectively reduce the parameters of pH, TSS, BOD, COD, and fatty oils. This research method is descriptive analytics, which analyses problems from data collected descriptively to find solutions to problems. The results of this evaluation show that the TSS, COD, and BOD parameters are above the quality standard threshold. The pH parameter increased by 3.6%, removal efficiency for BOD by 76.4%, COD by 71.9%, TSS by 84.3%, and oil grease by 91.9%. Alternative WWTP improvements are carried out by redesigning the Communal WWTP, which consists of calculating the equalization unit, precipitator I, anaerobic filter, Precipitator II, disinfection, and sludge thickener, Sludge digester, sludge drying bed and analysis of the Budget Plan Cost (RAB). The communal WWTP redesign requires a land area of 52.62 m2 with a processing capacity of 56.8 m3 and a cost budget plan of Rp.157,224,000.00. The redesign results of this evaluation can reduce environmental impacts due to domestic wastewater.

A Contact Characteristic of Roller Bearing with Palm Oil-based Grease Lubrication

Grease lubricants are widely used in rolling contact applications to reduce friction between two rolling surfaces. Improper lubrication may cause high contact stress and deformation to the bearings and lead to machine failure The purpose of this study is to investigate the coefficient of friction produced by newly developed palm oil-based grease and to investigate the contact characteristics in lubricated roller bearings. In this work, the coefficient of friction of new greases was evaluated experimentally and the values were compared with the conventional mineral oil-based grease to investigate the friction performance. The friction test was performed using a four-ball tester. The finite element model was developed based on the roller bearing geometry and the simulation was carried out the evaluate the contact characteristic. The experimental result shows that the palm oil grease formulation A had the least coefficient of friction, followed by palm oil grease formulation B, mineral grease and food grade grease. This indicates that palm oil-based grease has the potential to be applied in rolling contact applications due to low friction characteristics. Finite element analysis shows that the maximum von Mises stress and total deformation for frictional contact are higher than the frictionless contact. For the frictional contact analysis with various lubricant COF, similar values were obtained with von Mises stress at 400.69 MPa and 3.4033×10-4 mm deformation. The finding shows that the small difference in grease COF did not affect the rolling contact. The finding also shows that the newly developed biodegradable grease has a similar performance in terms of rolling contact friction and contact characteristic in a condition that the bearing is operating in normal condition.

Role of PGPR on the physiology of sunflower irrigated with produced water containing high total dissolved solids (TDS) and its residual effects on soil fertility

The present study was conducted to evaluate the bioremediation potential of plant growth-promoting rhizobacteria (PGPR) PGPR isolates from high total dissolved solids (TDS) bearing produced water on the water quality, soil physicochemical properties and growth and physiology of sunflower irrigated with high TDS bearing produced water having salinity level 130 times higher above seawater and also containing traces of oil and grease. Seeds of sunflower hybrid Parsun 3 were soaked for 3–4 h prior to sowing in 72 h old culture of PGPR strains W1 and W2 isolated from high TDS bearing polluted water. The control plants were irrigated with 90% diluted TDS water supplemented with 5 ml LB media. Whereas, the inoculated plants were irrigated with 90% diluted TDS water supplemented with 5 ml PGPR inocula.in LB media. The plants were grown under natural conditions. The 16S rRNA sequence analyses identified the isolate W1 bearing 100% similarity with the plant growth-promoting rhizobacteria (PGPR) Ralstonia pickettii and W2 bearing 99.7% similarity with Brevibacillus invocatus. Both the isolate were catalase and oxidase positive. The Ralstonia pickettii and Brevibacillus invocatus treatments decreased the EC and TDS values significantly such that the EC and TDS values of 90% diluted TDS water were 29 times and 19 times higher than tap water. Sodium adsorption ratio (SAR), organic matter, nitrogen, potassium, magnesium and carbon content were 1.96, 1.10, 2.28 1.20, 6.63 and 1.00 times greater than control in the rhizosphere soil of Ralstonia pickettii inoculated plants irrigated with high TDS bearing water There were significant increases in plant growth, sugar, flavonoids and phenolics, chlorophyll b, total chlorophyll, carotenoids content and activities of superoxide dismutase, catalase and peroxidase in plants inoculated with Ralstonia pickettii and Brevibacillus invocatus. The flavonoids, phenolics and proline contents were 0.54, 0.72 and 0.30 times higher in Ralstonia pickettii inoculated plants. Shoot/root dry weight ratio was about (50%) lower than control in Ralstonia pickettii and Brevibacillus invocatus treatments. Ralstonia pickettii was more effective than Brevibacillus invocatus to combat oxidative and osmotic stresses. It is inferred that the high TDS bearing produced water from oil factory harbor Plant growth-promoting rhizobacteria (PGPR) having the potential to combat high salinity stress in plants when used as bioinoculant. The broth culture containing the bacteria may be supplemented with the saline water used for irrigation as it provides nutrients for the growth and proliferation of bacteria present in the saline water and hence the synergistic action of bacterial inocula with the indigenous bacteria present in saline water may better alleviate osmotic and oxidative stresses of plants encountered under salinity stress. The residual effect of Ralstonia pickettii on organic matter and Ca, Mg, K and P content of the rhizosphere soil was notably higher for succeeding crops. Novelty statement This is the first report demonstrating that rhizobacteria can proliferate in water containing salinity higher above seawater in addition to oil grease and TSS. Their efficiency to reduce TDS can be augmented by an exogenous supply of LB broth culture of PGPR isolated from the polluted water. These indigenous rhizobacteria when used as bioinoculant on the plant can act as plant growth promoters as well as bioremediation of salinity effects.

The Application of Anaerobic Plastic Media Biofilter for Removal of Ammonia and Oil and Grease in Slaughterhouse Wastewater

Slaughterhouse wastewater generally contains organic substances, fatty oils and ammonia which can cause pollution to the environment. This study aims to analyze the removal efficiency of ammonia, oil and grease and pH of the slaughterhouse wastewater from Banda Aceh using an anaerobic biofilter. The bioreactor was acclimatized for 30 days to form a biofilm layer before being used as a biofilter. The results showed a decrease in the oil and grease content and pH of the slaughterhouse wastewater after given 6 days contacted time. Ammonia parameter increased by 2.02%, while the efficiency of oil and grease and pH also increased by 96.667% and 30.927%, respectively. It can be concluded that the anaerobic plastic media biofilter has been able to reduce the oil grease content and pH of slaughterhouse below the quality standard, except for ammonia which exceeds the quality standard of Environmental Government Regulation no. 5 of 2014.

Pyrolysis-Gas Chromatography/Mass Spectrometry Analysis of Oils from Different Sources

Regenerated gutter oil (i.e., waste oil) accounts for 10% of the edible oil market, which has caused serious food safety issues. Currently, there is no standard protocol for the identification of the gutter oil. In this study, the pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) method was employed to analyze eleven oil samples including edible vegetable oils (tea oil, corn oil, olive oil, sunflower oil, peanut oil and blend vegetable oil) and waste oils (used frying oil, lard, chicken fat, inferior oil and kitchen waste grease). Three factors of pyrolysis temperature, reaction time and sample volume were investigated to optimize the analytical parameters. The optimal pyrolysis conditions were determined to be 600°C, 1 min and an injection volume of 0.3 μL. Five characteristic components (tetradecane, z,z-9,12-octadecadienoic acid, decanoic acid-2-propenyl ester, 17-octadecenoic acid, and z-9-octadecenoic acid) were found in all oil samples. The existence of C11-C16 olefins in the pyrolytic products of the animal fats and the other low-quality oils could be utilized to distinguish vegetable oils from gutter oils.

Effects of feeding frequency and oil supplementation on feeding behavior, ruminal fermentation, digestibility, blood metabolites, and milk performance in late-lactation cows fed a high-forage diet

Many dairy producers are keen to feed low-producing late-lactation cows only once per day (1×) to reduce production costs. This study examined effects of feeding frequency (FF: thrice versus once daily) on behavioral patterns, ruminal fermentation, and milk production performance of cows and supplementation of yellow grease oil (YO) rich in 18:2n-6 as a potential strategy to alleviate the possible negative effects of 1× daily feeding. Twenty-four late-lactation Holstein cows (215 ± 53.8 DIM) housed in tiestalls were assigned to 4 treatments according to a 2 × 2 factorial arrangement with 2 FF [3 times daily (3×) at 0800, 1400, and 2000 h; or 1× at 0800 h] and 2 high-forage total mixed rations (TMR), without (CON) or with 25 g/kg of dry matter of YO (YGO), in a randomized complete block design. Treatments were applied for 21 d. Feeding behavior was recorded every 5 min over a 24-h period on d 19. Fresh TMR and orts were sampled (d 15 to 21) and separated using a 3-screen (19, 8, and 1.18 mm) Penn State Particle Separator for sorting activity. Ruminal fluid samples were collected using oral stomach tubing on d 21. Cows on 1×-CON spent more time eating during the first 6 h after feeding at 0800 h than did cows on 3×-CON or 1×-YGO. Decreasing FF increased meal length and tended to increase meal size for CON cows, but supplementing YO increased meal bouts and reduced meal length and size for cows fed 1×. Cows on 1×-CON had the greatest ruminating time between 2000 and 0800 h compared with other treatments. Total and daytime distribution of lying time did not vary by treatments. Sorting activity was higher for cows fed frequently, and the extent of sorting was increased by oil supplementation. In the morning ruminal fluid samples, pH was not different among treatments, but in the evening samples 1× daily feeding reduced ruminal pH compared with 3×. In the morning and evening samples, ratios of acetate to propionate were the lowest for 1×-CON cows compared with other treatments. Dry matter intake and milk yield were similar among the groups. Milk fat content and yield decreased with 1×-CON treatment, but supplementing YO numerically increased milk fat for cows fed 1×. These results suggest that decreasing FF from 3× to 1× daily increases meal length, particularly after feed delivery, in cows fed high-forage diets; but supplementation of plant oil changes feeding patterns and may improve ruminal pH and milk fat in cows fed once a day.

Grease oil humidity sensor by using metamaterial

Interaction between water and lubrication grease oil is not desirable, but it is not inevitable. The operational life of the machine component is influenced by humid grease oil. Metameterial-based transmission line sensor application is proposed and its operation is validated both numerically and experimentally by inserting grease oil samples in the sample holder. The proposed sensor structure is able to determine the humidity ratio of grease oil samples. The proposed structure shifts resonance frequency to react to the grease oil’s dielectric constant. The frequency shift of grease oil samples is monitored as about 300 MHz’s. Linearity characteristic between resonant frequency and dielectric constant value is validated. The novelty of this article is that no such study has been conducted by employing non-destructive methods which provide long-term stability of the sensor structure.

Effect of dietarySchizochytriumsp. oil as an n‐3 long‐chain polyunsaturated fatty acid source on growth performance, lipid metabolism and antioxidant status in juvenile grass carp (Ctenopharyngodon idellus): A comparative study with fish oil

Four isonitrogenous and isoenergetic semi-purified diets including control group (excluding n-3 long-chain polyunsaturated fatty acid [n-3LC PUFA]), fish oil group (FO), Schizochytrium sp.—stearin oil group (SO) and Schizochytrium sp.—wax grease oil group (WGO) (all three groups containing 0.52% n-3LC PUFA) were prepared to feed grass carp for 56 days. Compared with the control, dietary FO, SO and WGO significantly promoted growth performance, increased the level of n-3 LC PUFA which was preferentially deposited in polar lipids in muscle. FO, SO and WGO groups had the same effects on inhibiting the crude lipid content of whole fish, decreasing the size of adipocytes and up-regulated mRNA expression of adipose TAG lipase (ATGL) in the adipose tissue, as well as obviously down-regulated mRNA expression of glutamate dehydrogenase (GLDH) in muscle. Interestingly, the content of crude protein in muscle and whole body was increased in SO group rather than FO group compared with control, and the expression of GLDH in SO group was lower than that in FO group in muscle. These results may contribute to the effects of lipid-lowering, protein deposition increasing and growth improvement of SO group. Overall, SO group exhibited better growth performance than FO group.

Treatment of zinc plating wastewater by combination of electrocoagulation and ultrafiltration process.

In this study treatment of zinc plating wastewater by combination of electrocoagulation (EC) and ultrafiltration (UF) processes was investigated. The effect of operating parameters such as wastewater pH, flow rate and membrane pore size on zinc removal was investigated to optimize the EC-UF process. The results showed that zinc removal was pH dependent and optimum pH was 9.0. The zinc removal over 99% was achieved by the combined EC-UF process with both 50 and 100 kDa membranes at pH 9.0 and current density of 5 mA cm-2. Suspended solids and oil-grease were also removed completely by the combined EC-UF process. The EC-UF process proved to be a promising technology for the treatment and recycling of zinc plating wastewater.

Microstructural characterisation of reclaimed asphalt pavement with rejuvenators

ABSTRACT Reclaimed asphalt pavement (RAP) is the deteriorated pavement material, containing aged binder and aggregates. A rejuvenator is normally added to the mixture to reduce its stiffness, by blending with the aged binder and changing the properties of the mixture. Therefore, it is necessary to have an insight into the microstructure of the RAP and rejuvenated RAP. In this study, waste engine oil (WEO), waste vegetable oil (WVO) and waste grease (WG) are used as rejuvenators, at different dosages. The interaction between the rejuvenator and RAP is evaluated through microscopic analysis, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The microscopic analysis has provided the orientation and distribution of the aggregate, depicting the significant increase in coating of aged binder on the RAP with the increase in the rejuvenator dosage. The FTIR and XRD results have shown that rejuvenator has restored the asphaltenes and maltenes ratio and fluidity of the RAP. WG has comprehensively enhanced the asphaltenes and maltenes ratio, compared to the WEO and WVO. However, microscopic analysis suggests that the WG has high agglomeration. Overall, it is concluded that 6% WVO is a perfect dosage to enhance fluidity of the RAP.

Environmentally Friendly Lubricating Greases from Coconut Oils and Palm Oil

The purpose of this study is to compare the lubricating grease from coconut oils and palm oil as base oils. The consistency, dropping point, and tribological properties of lubricating greases were investigated and compared between coconut oils and palm oil. The consistency and dropping point were measured to investigate physical properties. Whereas, the pin on disc apparatus was used to investigate wear and coefficient of friction. The results indicate that the coconut oil greases show superior tribological properties when compare to the palm oil grease.

Low-cost yellow sticky traps against greenhouse whitefly Trialeurodes vaporariorum (westwood) in tomato under polyhouse

Eleven types of yellow sticky traps (15x30 cm) made up of different base and sticky materials were evaluated to determine their persistence and attractancy for greenhouse whitefly Trialeurodes vaporariorum (Westwood) in tomato under polyhouse during summer, rainy and winter cropping seasons. Base materials like yellow coloured thick paper and yellow painted galvanized iron sheet, and sticky materials like castor oil, mustard oil, linseed oil and white lithium grease were evaluated.The cumulative adult catches on traps evaluated remained significantly maximum (594.3 to 1118.0) during rainy season. Use of paper sheet smeared with different pasting materials resulted in significantly more trap catches, compared to the use of iron sheet. Irrespective of the base material, traps smeared with castor oil proved significantly superior followed by that of mustard oil, linseed oil and white lithium grease. The cost of traps ranged from Rs 165 to Rs 2025/cropping season of 140 days/250 m2 polyhouse; with the minimum and maximum being for the white lithium grease pasted on plastic sheet and commercial trap, respectively. The trap with castor oil pasted on paper sheet was good in efficacy but not cost effective. Trap with mustard oil pasted on paper sheet was one of the efficacious traps, and also cost effective.

Assessment of Dose Rate and Risk Due To the Clean-Up Activities of Depleted Uranium Workshop from the IFIN-HH VVR-S Research

The IFIN-HH VVR-S type Nuclear Research Reactor is currently in the decommissioning phase. During the operation period inside of the reactor building a workshop for mechanical processing of depleted uranium blocks was used. The purpose was containers manufacturing for biological shielding of Cs-137 and Co-60 sources. The dose rate and associated risk for workers performing clean-up and decontamination of the workshop was assessed using RESRAD Build 3.5 code. As a result of the workshop radiological characterization performed in 2007 it was revealed the presence of U-238 as dust particles embedded in the oil grease. The main risk for workers contamination was internal by aerosols inhalation as well as external by hand touching of the contaminated surfaces. The time for clean-up and decontamination operation was 2 weeks, and therefore the estimation was made for this period.

Effect of grease on bearing vibration performance caused by short-time high-temperature exposure

A short-time high-temperature environment is a common working condition in the use of bearings; it can occur as rapid heating before interference assembly of a bearing, or in a quick shutdown due to failure and heating of other parts of equipment. However, the current research mainly focuses on the influence of long-term high temperatures on bearing lubrication. In this paper, the 6204DDU ball bearing with lithium soap/mineral oil (paraffin base type) grease and fatty acid soap/mineral oil (refined white oil) grease (white grease) is investigated. The recovery performance of the two greases after a short-time high temperature is studied. It is found that a large number of fractures occur in the soap fibre of the white grease after 20 min exposure in 140 °C temperature environments, while lithium grease remains in a good working condition. The vibration velocity with white grease decreases during a temperature falls from 110 °C to the heated balanced temperature, while the vibration velocities with lithium grease is without significant fluctuations. Before and after heating, the vibration velocities in middle frequency band of rolling bearings with lithium grease and white grease increase with the increase in preload, but it is the opposite in the high frequency band except for white grease after heating condition. Infiltration with a small amount of water or oil can greatly affect the performance of white grease. Water can emulsify the white oil and accelerates the oxidation of white grease. The structure of the L-AN32 oil contaminant is different from that of white oil, resulting in uneven dispersion of saponified crystals and obvious flocculent agglomeration is presented.

Propagation behavior of hydraulic fracture across the coal-rock interface under different interfacial friction coefficients and a new prediction model

Indirect fracturing from rocks to coal is a promising technology of coalbed methane exploitation in soft and low-permeability coal seams. Central to this technology is the prediction of the propagation path of the fluid-driven fractures at the coal-rock interfaces, which requires a deep understanding of the role of the friction properties of coal-rock interfaces. In this paper, we performed hydraulic fracturing experiments using coal-rock blocks with interfaces that were not lubricated, lubricated by oil grease or Vaseline. The results show that the fracture behaviors at different interfaces depend mostly on the vertical stress and the interfacial friction coefficients. Only when the vertical stress reaches a certain threshold, can the fractures directly penetrate the interfaces, where the threshold value increases gradually as the interfacial friction coefficient decreases. Moreover, the abrupt change in the interfacial friction causes hydraulic fractures to deflect at the interface. The injection pressure evolution curves are significantly different due to different fractures behaviors at the interfaces. When hydraulic fractures penetrate the interface, the injection pressure evolution curve shows a significant secondary rise. A distinct prediction model of hydraulic fractures across the coal-rock interface that considers the interfacial friction, the stress state and the intersection angle between the hydraulic fracture and the coal-rock interface was established. This model shows high accuracy in predicting the propagation behavior of hydraulic fracture at different interfaces in hydraulic fracturing.

Treatment of carwash wastewater by electrocoagulation using Ti electrode: optimization of the operating parameters

Electrocoagulation process using Ti electrode was employed for carwash wastewater treatment. Taguchi experimental design method was applied to identify the optimized values of operating parameters for chemical oxygen demand, anionic surfactant and oil–grease removals. The effects of operating parameters on the removal of selected pollutants were investigated. The operating variables were selected as pH: 4–8; current density: 2.5–30 A/m2; stirring speed: 150–350 rpm. 84% chemical oxygen demand, 99.3% anionic surfactant and 82% oil–grease removal efficiencies were achieved under the optimized conditions. The operating cost was calculated as 9.67 $/m3 for these conditions. The analysis of variance results indicated that the current density had the greatest effect on the removals. EC sludge produced at the optimum conditions was analyzed using environmental scanning electron microscopy–energy-dispersive X–ray and Fourier transform infrared spectroscopy analyses. The results indicated that Taguchi design method was suitable to determine the optimum values of operating parameters for EC treatment of carwash effluents. High chemical oxygen demand, anionic surfactant and oil–grease removals showed that electrocoagulation process using Ti electrode can be used for the removal of organic matters from carwash effluents.