Industrial Oily Wastewater Research Articles

Performance evaluation of an oily industrial wastewater treatment system using the application of activated sludge model No. 3

AbstractThe purpose of the present study was to adapt the activated sludge model No. 3 (ASM3) to the characteristics of oily industrial wastewater, determining the utmost significant and appropriate kinetic as well as stoichiometric parameters. An oily industrial wastewater treatment system was simulated to assess ASM3 validation and perform sensitivity analysis using the STOAT program. The obtained results revealed that the ASM3 model, which was calibrated after adding the Arrhenius equation into consideration, provided strong correlations with the analytical results of chemical oxygen demand (COD), total suspended solids (TSS), mixed liquor volatile suspended solids (MLVSS) and total suspended solids in the return activated sludge flow (TSS in RAS) concentrations. The values of modelled effluent COD and TSS are very close to those corresponding real values of the treated wastewater by a difference of between 0.5% and 1.5%. Thus, this model becomes successful in representing oily industrial wastewater treatment as a new trend added to the traditional modelling of sewage treatment.

Preparation of cellulose/chitosan superoleophobic aerogel with cellular pores for oil/water separation

Nanofibrillated cellulose (NFC)/chitosan (CS) composite aerogel with underwater superoleophobicity was prepared by freeze-drying for oil/water separation. The soft-ice freezing technique was employed to construct cellular pores for improving the mechanical performance while enhancing mass transfer of freeze-drying. The dielectric-aided microwave heating was adopted to enhance heat transfer of freeze-drying. The results showed that the prepared NFC/CS aerogel exhibited an excellent mechanical property with a stress of 87.16 kPa at 80% strain, and underwater superoleophobicity with all oil contact angles above 150˚. The proposed drying method could save over 40% of drying time, achieving a simultaneous mass and heat transfer enhancement of freeze-drying. The prepared aerogel provided separation efficiencies of all above 99.96% and average permeate fluxes of 0.817 and 0.826 L·m−2·s−1 after 20 cycles for oil/water and oil/seawater separations. The research results are expected to provide an economical and sustainable solution for the industrial oily wastewater treatment.

Facile, green and scalable preparation of low-cost PET-PVDF felts for oil absorption and oil/water separation

3D felt materials with pore structures have the advantages of high absorption performance and recyclability in oily wastewater treatment and chemical leakage. However, most of them were fabricated using either toxic organic solvents or complicated procedures. Herein, we report a facile, green, and scalable route for the fabrication of 3D composite felts with large pore structures by sequentially stirring and heating polyethylene terephthalate (PET) fibers and polyvinylidene fluoride (PVDF). The resulting PET-PVDF felt exhibits high oil absorption capacity to a variety of oil and organic solvents with a maximum saturated absorption capacity of 32 g/g. Additionally, it can be used to separate oil/water mixtures with a separation efficiency of 99.9% and separation flux of 89570 L m−2 h−1. Moreover, this felt shows excellent mechanical durability and chemical stability under acid, base, salt solution, and other harsh environments. The current study provides a promising approach for large-scale industrial oily wastewater separation.

Glutaraldehyde functionalized modified chitosan and grafted on PVDF membrane to achieve oil-water separation

In recent years, there have been frequent offshore oil spills, and the discharge of industrial oily wastewater has not been properly solved, seriously affecting biological and water quality, and people's requirements for water quality are getting higher and higher, so it has become increasingly urgent to find green and efficient technologies and methods for separating oil-water mixtures. In this work, glutaraldehyde, a widely used crosslinker, is used to graft natural polysaccharide chitosan onto PVDF membrane, which greatly enhances the hydrophilicity of PVDF membrane, and the superhydrophilic superoleophobic CG-PVDF membrane prepared can be used to treat oily wastewater. The materials for preparing membranes are inexpensive, easy to obtain, and environmentally friendly, recyclable, and will not cause secondary pollution. Therefore, this green and simple membrane separation method for the treatment of oily wastewater is of great significance in sustainable development.

In-situ activation of Fe78Si9B13 metallic glasses for electro-Fenton degradation of industrial oily wastewater

Metallic glasses (MGs) with superior catalytic properties have attracted widespread attention towards organic wastewater remediation. However, the low degradation efficiency of industrial oily wastewater by the conventional ways and materials hinders practical applications. Herein, Fe78Si9B13 MGs as highly efficient electrodes exhibit excellent catalytic performance for electro-Fenton degradation of oily wastewater for the first time. The oil removal rate and chemical oxygen demand (COD) removal rate are as high as 81.8% and 77.3% within 120 min under optimum experimental parameters. Compared to other electrode materials, Fe78Si9B13 MG electrodes possess the more preferable catalytic capability. Additionally, two degradation processes related to direct oxidation of electrochemical action and mediated oxidation of activated radicals may be accurately certified. These findings will develop a functional material and provide a potential approach for environmental applications of purification of refractory organic contaminants.

Recent Advances in Superhydrophobic Papers for Oil/Water Separation: A Mini-Review.

The separation of oceanic spilled oils and industrial oily wastewaters becomes a great challenge, and it is highly desirable to develop efficient materials for oil/water separation. As abundant sustainable resources, superhydrophobic papers (SPs) have drawn much attention because of low-cost and efficient oil/water separation. Herein, this mini-review summarizes recent advances of SPs in terms of design, preparation, and properties. On the basis of the many excellent properties of SPs (i.e., self-cleaning, durability, chemical corrosion resistance, and reusability), the oil/water separation performances (i.e., separation efficiency, permeation flux, and recyclability) of SPs as well as the corresponding mechanisms are discussed. The efficient oil/water separation property and recyclability of SPs make them promising candidates in the field of oily wastewater treatment.

Facile preparation of hydrophilic PVDF membrane via tea polyphenols modification for efficient oil-water emulsion separation

Facile preparation of hydrophilic membranes is essential for achieving efficient separation of oil-water emulsion. In this paper, a hydrophilic PVDF@TP membrane was prepared by very simple direct modification using green tea (The main extract is tea polyphenols, TP). The PVDF@TP membrane exhibits good hydrophobicity in air and underwater superoleophilicity. The oil-water separation potential of this membrane was studied using several model oil-in-water emulsions. The resulting membrane exhibitd high separation efficiency (above 99 %) and separation fluxes (955–1672 L m−2 h−1 bar−1) for various oil-in-water emulsions. Additionally, separation efficiency of PVDF@TP membrane was still above 98 % even after 10 times continuous separation, demonstrating its good antifouling ability and stability. In addition, bending, ultrasonic and stirring treatments showed that the membrane has good mechanical durability. In view of the advantages of facile preparation, economy and high-performance, the hydrophilic PVDF@TP membrane has a very broad application potential in industrial oily wastewater and oil spill treatment.

Microbiological analysis and bioremediation bioassay for characterization of industrial effluent

This study aims to investigate bacteria for biodegradation of oil pollutants from oily industrial wastewater to be used as bioremediation tools and to determine the characterization of bioremediation bioassays. A screening bioassay was carried out using six exogenous environmental bacterial strains to degrade oily pollution, which indicated promising clearance of the oily wastewater. Two strains, namely Enterobacter cloacae 279-56 (R4) and Pseudomonas otitis MCC10330 (R19), could successfully eliminate oil content and reasonable removal of the organic load. Results showed that the two promising bacterial candidates (R4 and R19) were selected according to the preliminary screening of the six tested bacteria considered the most efficient for all the tested parameters. The highest Removal Efficiency (Removal Efficiency resulted in Residual levels of total dissolved solids (TDS), biochemical oxygen demand, chemical oxygen demand, and Oil content in the treated oily wastewater effluents are 1940, 171, 131, and 84 mg/l respectively where these results are not within safe discharge limits, except for TDS. Hence, the bioremediation assays were carried out using the mixed culture since it was the most efficient strain for degrading all tested parameters.

Application of combined granular media with opposite wettability for demulsification of oily wastewater by microchannel filter

Oil-water separation with high efficiency and low energy consumption is a tremendous challenge in the green treatment of oily wastewater. In this paper, a novel filtration method with combined granular media for collaborative removal emulsified oil and suspended solids (SS) was proposed, followed by the exploration of demulsification feasibility and oil removal mechanism. The effect of the operation and structural parameters of the filter bed on oil separation performance was thoroughly investigated, and its feasibility for raw oily wastewater treatment was also explored. A remarkable demulsification performance was observed with the combined granular media filter, and a balance of separation efficiency and pressure drop in the emulsified oily wastewater filtration was also achieved subsequently. Effective oil droplet capture and coalescence were observed with a high speed camera system, and pore clogging could be avoided in combined media. The optimal parameters of the combined media filter (CMF) were concluded to be a combined media ratio of 1:1, a superficial velocity of 0.20 m min−1, and a bed porosity of 58.1%. The average oil and suspended solids concentrations in raw oily wastewater was decreased to 8.4 mg/L and 23.3 mg/L during the pilot-scale operation, which indicated that the novel filter composed of combined media had better performance in collaboratively removing oil and SS, even in the period of fluctuating influent parameters. It is believed that a novel and efficient oil removal method, especially including of emulsified oil removal was provided, which also shows great potential and value for the green treatment of industrial oily wastewater.

Efficient oil-water emulsion treatment via novel composite membranes fabricated by CaCO3-based biomineralization and TA-Ti(IV) coating strategy

Continuous increasing discharge of industrial oily wastewater and frequent occurrence of oil spill accidents have taken heavy tolls on global environment and human health. Organic-inorganic modifications can fabricate superhydrophilic/submerged superoleophobic membranes for efficient oil-water separation/treatment though they still suffer from complex operation, non-environmental friendliness, expensive cost or uneven distribution. Herein, a new strategy regarding tannic acid (TA)-Ti(IV) coating and CaCO3-based biomineralization through simple inkjet printing processes was proposed to modify polyvinylidene fluoride (PVDF) membrane, endowing the membrane with high hydrophilicity (water contact angle (WCA) decreased from 86.01° to 14.94°) and underwater superoleophobicity (underwater contact angle (UOCA) > 155°). The optimized TA-Ti(IV)-CaCO3 modified membrane possessed perfect water permeation to various oil/water emulsions (e.g., 355.7 L·m−2·h−1 for gasoline emulsion) under gravity with superior separation efficiency (>98.8 %), leading the way in oil/water emulsion separation performance of PVDF membranes modified with polyphenolic surfaces to our knowledge. Moreover, the modified membrane displayed rather high flux recovery after eight cycles of filtration while maintaining the original excellent separation efficiency. The modification process proposed in this study is almost independent of the nature of the substrate, and meets the demand for simple, inexpensive, rapid preparation of highly hydrophilic antifouling membranes, showing abroad application prospect for oil-water emulsion separation/treatment.

Surface modification of porous polyvinylidene fluoride hollow fiber membrane by sulfonated poly(ether ether ketone) coating for membrane distillation of oily wastewater

AbstractHighly porous polyvinylidene fluoride hollow fiber membranes were fabricated by a non‐solvent induced phase separation process. The membranes were modified by coating an ultra‐thin hydrophilic layer of sulfonated poly(ether ether ketone) (sPEEK) onto the inner surface. An industrial oily wastewater treatment was performed through an air gap membrane distillation (AGMD) process. From field emission scanning electron microscopy, the modified membrane showed an open structure with a large finger‐like outer layer and sponge‐like inner layer. The thickness of the coated sPEEK layer on the inner surface was about 0.5 μm. The coated membrane presented mean pore size of 36 nm and overall porosity of 73%. The inner surface water contact angle decreased from about 82° to 57°. Using Langmuir adsorption experiment, minor oil adsorption on the modified membrane surface was confirmed. A stable water flux of about 12 kg m−2 h−1 and oil rejection of 99% were found during 72 h of the AGMD process for treating the oily wastewater of NGL‐900 (Gachsaran, Iran) plant. The high flux recovery ratio of about 98% was related to the improved anti‐oil‐fouling property. The modified membrane can be a potential candidate for oily wastewater treatment through the MD processes.

Highly durable and sustainable heterogeneous fabric using in-and-out fluorinated urethane coating for elimination of bacteria and oil–water separation

To address the poor oil–water separation efficiency and bactericidal properties of existing oil–water separation membranes for the treatment of industrial oily wastewater discharge, this study designed an in-and-out coating material for modifying the inner site and outer surface of porous activated carbon fabric (ACF) using urethane reactions. To this end, fluorinated polyurethane (F-PU) coating materials were synthesized using perfluoroalkyl alcohol, ethylene glycol (EG), and isophorone diisocyanate (IPDI). Subsequently, the inner and outer surface of the ACF were coated with F-PU via the urethane reaction of the hydroxyl groups (–OH) of the surface of ACF and the isocyanates of F-PU. The successfully fabricated in-and-out F-PU-coated heterogeneous fabric exhibited excellent hydrophobic properties, anti-scratch performance, oil–water separation performance, and bacterial penetration blocking efficiency (>99% for gram negative and gram positive bacteria). Furthermore, the in-and-out-coated ACF exhibited high durability, and retained its bacterial penetration blocking performance after scratch tests.

Intelligent Coatings with Controlled Wettability for Oil-Water Separation.

Intelligent surfaces with controlled wettability have caught much attention in industrial oily wastewater treatment. In this study, a hygro-responsive superhydrophilic/underwater superoleophobic coating was fabricated by the liquid-phase deposition of SiO2 grafted with perfluorooctanoic acid. The wettability of the surface could realize the transformation from superhydrophilicity/underwater superoleophobicity (SHI/USOB) to superhydrophobicity/superoleophilicity (SHB/SOI), both of which exhibited excellent separation performance towards different types of oil–water mixtures with the separation efficiency higher than 99%. Furthermore, the long-chain perfluoroakyl substances on the surface could be decomposed by mixing SiO2 with TiO2 nanoparticles under UV irradiation, which could reduce the pollution to human beings and environment. It is anticipated that the prepared coating with controlled wettability could provide a feasible solution for oil–water separation.

Review of Biological Processes in a Membrane Bioreactor (MBR): Effects of Wastewater Characteristics and Operational Parameters on Biodegradation Efficiency When Treating Industrial Oily Wastewater

Oily wastewater is generated from various sources within the petrochemical industry, including extraction, refining and processing, storage, and transportation. Over the years, large volumes of oily wastewater from this industry have made their way into the environment, negatively affecting the environment, human health, and the economy. The raw waters from the petrochemical industry can differ significantly and have complex features, making them difficult to treat. Membrane bioreactors (MBR) are a promising treatment option for complex wastewater; it is a combined physical and biological treatment. The biological component of the MBR is one of the main contributing factors to its success. It is important to know how to control the parameters within the bioreactor to promote the biodegradation of hydrocarbons to improve the treatment efficiency of the MBR. There have been many reviews on the effects of the biological factors of membrane fouling; however, none have discussed the biodegradation process in an MBR and its impact on effluent quality. This review paper investigates the hydrocarbon biodegradation process in an aerobic MBR system by gathering and analyzing the recent academic literature to determine how oily wastewater characteristics and operational parameters affect this process.

2D Nano-Mica Sheets Assembled Membranes for High-Efficiency Oil/Water Separation.

Oil-polluted water has become one of the most important environmental concerns nowadays due to the increasing industrial oily wastewater and frequent oil spill accidents. Herein, a novel two-dimensional (2D) nano-mica sheets assembled composite membrane with underwater super-oleophobic properties was developed for effective oil/water separation. A 2D nano-mica sheet was synthesized by a facile solvent-assisted ultrasonic exfoliation and then the obtained 2D nano-mica sheets were co-deposited with dopamine on polyvinylidene fluoride substrate to prepare nano-mica composite membranes (NCM). The NCM is hydrophilic in air and super-oleophobic underwater (the water contact angle in the air is 37.6°, and the oil contact angle in water is 151.4°). Furthermore, the prepared NCM provided outstanding stability in different acid–base environments (pH = 1–11). Noteworthily, the oil removal rate is higher than 99.5% as the sodium dodecyl sulfate SDS-stabilized oil (soya-bean oil, mineral oil and pump oil) -in-water emulsions. Meanwhile, the NCM showed excellent reusability, as the oil removal efficiency kept at 99.0% after ten soya-bean oil-in-water or mineral oil-in-water emulsion filtration cycles. The present work paved a new way for developing a low-cost and environmentally friendly strategy for oily wastewater treatment and developed a high-increment utilization application field for natural minerals.

Hierarchically structured biomimetic membrane with mechanically/chemically durability and special wettability for highly efficient oil–water separation

Membrane-based materials with selective superantiwetting/superwetting surfaces have been applied widely to tackle the concerns of the ever-growing discharge of industrial oily wastewater, as well as frequent oil spill accidents. However, conventional membrane-based separation technologies are inefficient and limited, either by insufficient robustness or by the inadequate anti-oil-fouling property. Herein, a biomimetic superhydrophobic membrane (BSM) with multiscale hierarchical structures (MHSs) was prepared through a method combing self-growth and spray coating. Remarkably, the BSM featured a static water contact angle of 153 ± 0.5°. Accordingly, the BSM possessed highly efficient oil–water separation capability (>95%). In addition, the anti-oil-fouling property and anti-drag capability in the oily seawater of BSM were systematically investigated. In fact, the repellent properties of BSM toward multiple mixtures were attributed to the synergistic effect of both physical structures (biomimetic MHSs) and hydrophobic chemical compositions. Moreover, the BSM demonstrated excellent mechanical robustness (the number of abrasion cycles reached 35) and chemical durability (maintain superhydrophobicity in pH 1–14) through abrasion and strong acid/alkali corrosion tests, respectively. The durability of BSM provided more possibilities for its practical applications. The findings in this work offer a facile yet effective strategy for designing superhydrophobic membranes with excellent physicochemical durability and suggest a great potential value for oil–water separation and drag reduction applications.

Electrospun Membrane with Ultrafine Fibers for Oil/Water Separation Application

Environmental pollution has become an urgent concern for both nature and human beings because of oily wastewater spills from industries and household appliances. Therefore, the filtration of industrial oily wastewater is now a major problem in the present world. Many types of experiments are being conducted to find a solution for this issue, and researchers are still looking for a cheaper and better solution. A promising response to this issue can be membrane-interfaced oil-water filtration. And the application of Electrospun membranes can successfully solve this matter. It is found that Polyvinylidene Fluoride-based membranes are being used for this process because of their resistance to chemicals and good mechanical strength. Also, Titanium Dioxide particles are a suitable choice because of their non-hazardous properties and solubility with polymer solutions. In this study, Titanium Dioxide nanoparticles were first synthesized by modifying their pH, and then Electrospun Nanofibrous membranes were produced by adding those modified particles with Polyvinylidene Fluoride. A unique preparation method was used to decrease the particle diameter with alkaline agents, which also results in decreased fiber diameter of membranes. The produced membranes showed improved oleophilic properties and hydrophobicity. Finally, membranes were applied and can be associated with the progress of Oil/Water separation purposes, which also can sustain the recycling process of hazardous chemicals and ensure the contribution to a safe environment.

Mussel-Inspired Durable TiO2/PDA-Based Superhydrophobic Paper with Excellent Self-Cleaning, High Chemical Stability, and Efficient Oil/Water Separation Properties.

Oceanic oil spill and the discharge of industrial oily wastewaters can cause significant threats to the ecological environment and human health. Herein, we design a durable TiO2/PDA-based superhydrophobic paper for efficient oil/water separation. Bioinspired from mussel adhesive proteins, the mechanical durability of the as-prepared superhydrophobic paper is enhanced by the deposition of polydopamine (PDA) onto cellulosic fibers via self-polymerization of dopamine. The TiO2/PDA-based superhydrophobic paper shows a high water contact angle of 168.2° and an oil contact angle of ∼0°, exhibiting excellent superhydrophobicity and superoleophilicity. Furthermore, the as-prepared superhydrophobic paper possesses excellent chemical stability, thermal stability, and mechanical durability in terms of being immersed in corrosive solutions and solvents and boiling water and being subjected to the sandpaper abrasion test, respectively. More importantly, the separation efficiency of the TiO2/PDA-based superhydrophobic paper for an oil/water mixture is 97.2%, and it maintains a separation efficiency above 94.3% even after 15 cyclic separation processes. Furthermore, the separation efficiency for water-in-oil emulsions is higher than 93.7% after 15 cyclic separation tests, showing its excellent recyclable stability for water-in-oil emulsions. Therefore, the rationally designed TiO2/PDA-based superhydrophobic paper shows great potential in the practical applications of self-cleaning, antifouling, and oil/water separation.

Preparation and research of Mn-TiO2/ Fe membrane with high efficiency light-oil/water emulsion separation

To control the water pollution caused by industrial oily wastewater, scientific research in the field of oil-water separation has begun all over the world, which has also attracted extensive attention to green advanced separation materials. Herein, we used stainless steel mesh as one of the reactants to load metal oxide particles formed by tetrabutyl titanate (TBT), and manganese acetate on cotton mesh under acidic conditions to prepare a membrane material with excellent oil-water separation. The results showed that the 0.1/0.3/0.5 Mn-TiO2/Fe membranes prepared by high-temperature hydrothermal reaction had an excellent separation effect in the light oil and water separation after 10 cycles, and its maximum oil-water separation efficiency was 89.87%, 92.65% and 96.96% respectively. At the same time, the membrane still had good hydrophobicity after acid, alkali and high temperature and low-temperature treatment. In the light oil and water separation experiment measured after 15 times of friction with sandpaper, the 0.5Mn-TiO2/Fe membrane showed good durability, and the average separation efficiency was 93.82% respectively. This diversified wettability and separation process of stainless steel mesh load on the membrane surface has a wide range of potential applications in environmental protection, energy utilization, industrial manufacturing and so on.

Preparation of high performance superhydrophobic PVDF-PbO2-ZrO2 composite electrode and its application in the degradation of paracetamol and industrial oily wastewater

• Super hydrophobic PVDF-PbO2-ZrO2 composite electrode was prepared by electrode position. • The degradation of paracetamol (APAP) by PVDF-PbO 2 -ZrO 2 composite electrode was studied, the optimum degradation conditions were discussed, and the possible degradation pathway of APAP was proposed combined with GC-MS. • Taking an industrial oily wastewater as an example, the practical application of the electrode is evaluated. Superhydrophobic PVDF-PbO 2 -ZrO 2 composite electrode was prepared by electrodeposition of polyvinylidene fluoride (PVDF) and zirconia (ZrO 2 ). The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) with EDS and water contact angle. The electrocatalytic degradation of paracetamol (APAP) by electrode was studied, the removal rate of APAP by electrode was 98.24% after 100 min, in addition, the degradation pathways include carboxylation of phenolic hydroxyl, C N bond breaking and benzene ring opening, then further oxidation to produce linear hydroxypropionic acid, and finally into CO 2 and H 2 O. Moreover, after 120 min degradation, the COD removal rate of the industrial oily wastewater reaches 83.33%. The oil content of the wastewater reduced from 148 to 4 ppm, which proves that the material possesses good practical application.