Demulsification techniques of water-in-oil and oil-in-water emulsions in petroleum industry

The difficulties associated with transportation and refining of crude oil emulsions and produced water discharge limitations are among the conspicuous clues that have led the oilfield researchers to probe into practical demulsification methods for many decades. Inconsistent research outcomes observed in the literature for a particular demulsification method of a typical emulsion (i.e., water-in-oil or oil-in-water) arise not only from the varied influential parameters associated (such as salinity, temperature, pH, dispersed phase content, emulsifier/demulsifier concentration, and droplet size) but also from the diverse types of emulsion constituents (namely oil, surfactant, salt, alkali, polymer, fine solids, and/or other chemicals/impurities). Being the main component in formation of stabilizing interfacial film surrounding the dispersed phase droplets, surfactant is the most predominant contributor to emulsion stability, extent of which depends on its nature (being ionic or nonionic, and its degree of hydrophilicity/lipophilicity), concentration, and interaction with other surface-active agents in the emulsion as well as on the salinity, temperature, and pH of the system. In this paper, it is endeavored to overview some of the most commonly exploited demulsification techniques (i.e., chemical, biological, membrane, electrical, and microwave irradiation) of both oilfield and synthetic emulsions, taking into account the emulsion-stabilizing and -destabilizing effects with regard to the dominant parameters plus the emulsion composition. Further, the variations occurring in interfacial properties of emulsions by demulsification process are discussed. Finally, the mechanism(s) involved in emulsions resolution achieved by each method is elucidated. Clearly, the most efficient demulsification approach is the one able to attain desirable separation efficiency while complying with the environmental regulations and imposing the least economic burden on the petroleum industry

Investigations of the effect of pore size of ceramic membranes on the pilot-scale removal of oil from oil-water emulsion

Oil-water emulsions are one of the most serious pollutants because of the large quantities produced by various industries, such as the petrochemical, oil and gas industries. One of the major methods to remove oil from wastewater is filtration using ceramic tubular microfiltration membranes. However, such membranes are vulnerable to fouling, which causes operational impairment. The aims of this work are to study the influence of membrane pore size on permeate flux and oil removal efficiency at different operating parameters and the reduction in fouling when used in combination with hybrid Coagulation/sand filter-MF pre-treatment process. The droplet size of the oil-water emulsion has an interaction with the pore size of the ceramic membrane. Therefore, each pore size may be optimal, depending upon the concentration of oil in the emulsion, and hence droplet size. Steady-state flux and oil removal efficiency were found to b highest for hybrid coagulation/sand filter –MF due to a reduction of membrane fouling by reducing the oil concentration in the inlet emulsion to the ceramic membrane

Desalination of Shale Gas Wastewater: Thermal and Membrane Applications for Zero-Liquid Discharge

Natural gas exploration from unconventional shale formations, known as “shale gas,” has recently arisen as an appealing energy supply to meet the increasing worldwide demand. During the last decade, development of horizontal drilling and hydraulic fracturing (“fracking”) technologies have allowed the cost-effective gas exploration from previously inaccessible shale deposits. In spite of optimistic expansion projections, natural gas production from tight shale formations has social and environmental implications mainly associated with the depletion of freshwater resources and polluting wastewater generation. In this context, the capability of desalination technologies to allow water recycling and/or water reuse is crucial for the shale gas industry. Advances in zero-liquid discharge (ZLD) desalination processes for treating hypersaline shale gas wastewater can play a key role in the mitigation of public health and environmental impacts, and in the improvement of overall process sustainability. This chapter outlines the most promising thermal- and membrane-based alternatives for ZLD desalination of shale gas wastewater.This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 640979

Liquid state bioconversion of sewage treatment plant sludge in batch fermenter and shake flask

A study on liquid state bioconversion of sewage treatment plant (STP) sludge was assisted to evaluate the performance of batch fermenter compared to shake flask in a laboratory. Bioconversion of STP sludge was highly influenced by the mixed fungal culture of Penicillium corylophilum and Aspergillus niger after 4 days of treatment. The results showed that about 24.9 g kg-1 dry sludge cake (DSC) was produced with enrichment of fungal biomass protein in fermenter while 20.1 g kg-1 in shake flask after 4 days of fungal treatment. The effective biodegradation of STP sludge was recorded in both fermenter and shake flask experiment compared to control (uninnoculated sample). The results presented in this study revealed that the overall performance of fermenter in terms of sludge cake (biosolids) accumulation and biodegradation of STP sludge was higher than the shake flask

Effect of agitation and aeration on bioconversion of domestic wastewater sludge in a batch fermenter

Effects of agitation and aeration rate on microbial treatment of domestic wastewater sludge were investigated in a batch fermenter using mixed culture of Penicillium corylophilum and Aspergillus niger. It was found that liquid state bioconversion (LSB) of wastewater sludge was highly influenced by the effects of agitation and aeration. The maximum production of sludge cake and reduction of organic substances in treated sludge were recorded at 150–200 rpm of agitation speed and 0.5 vvm of aeration rate after 72 h of treatment. No effective results were observed at higher rate of agitation (300 rpm) and aeration (1.5 vvm) as compared to optimum values. The results showed that the minimum level of air saturation (pO2) was adequate to maintain the bioconversion process

Effect of synthesis condition on the growth of SWCNTs via catalytic chemical vapor deposition

Single-walled carbon nanotubes (SWCNTs) were synthesized by catalytic chemical vapor deposition (CCVD) of ethanol (C2H5OH) over Fe-Mo-MgO catalyst by using argon as a carrier gas. The reaction conditions are important factors that influence the yield and quality of carbon nanotubes. The effects of temperature and flow rate of carrier gas were investigated to increase the yield of carbon nanotubes. The synthesized carbon nanotubes were characterized by scanning electron microscopy, transmission electron microscopy, X-Ray diffraction and thermo-gravimetric analysis. The results showed that the growth of carbon nanotubes wass effectively influenced by the reaction ambience and the synthesis condition. The temperature and flow rate of carrier gas played a key role in the yield and quality of synthesized CNTs. The estimated yield of synthesized carbon nanotubes was almost over 70%

Enhanced settleability and dewaterability of fungal treated domestic wastewater sludge by liquid state bioconversion process

A study was conducted to evaluate the settleability and dewaterability of fungal treated and untreated sludge using liquid state bioconversion process. The fungal mixed culture of Aspergillus niger and Penicillium corylophilum was used for fungal pretreatment of wastewater sludge. The fungal strains immobilized/entrapped on sludge particles with the formation of pellets and enhanced the separation process. The results presented in this study showed that the sludge particles (pellets) size of 2–5mm of diameter were formed with the microbial treatment of sludge after 2 days of fermentation that contained maximum 33.7% of total particles with 3–3.5mm of diameter. The settling rate (measured as total suspended solids (TSS) concentration, 130 mg/l) was faster in treated sludge than untreated sludge (TSS concentration, 440 mg/l) after 1 min of settling time. In 1 min of settling operation, 86.45% of TSS was settled in treated sludge while 4.35% of TSS settled in raw sludge. Lower turbidity was observed in treated sludge as compared to untreated sludge. The results to specific resistance to filtration (SRF) revealed that the fungal inoculumhad significant potentiality to reduce SRF by 99.8% and 98.7% for 1% w/w and 4% w/w of TSS sludge, respectively. The optimum fermentation period recorded was 3 days for 1% w/w sludge and 6 days for 4% w/w sludge, respectively, for dewaterability test

Use of fungi to improve bioconversion of activated sludge

TThe present study was designed to evaluate the potential of microbial adaptation and its affinity to biodegradation as well as bioconversion of soluble/insoluble (organic) substances of domestic wastewater treatment plant (DWTP) sludge(activated domestic sludge) under natural/non sterilized conditions. The two filamentous fungi, Penicillium corylophilum (WWZP1003) and Aspergillus niger (SCahmA103) were used to achieve the objectives. It was observed that P. corylophilum (WWZP1003) was the better strain compared to A. niger (SCahmA103) for the bioconversion of domestic activated sludge through adaptation. The visual observation in plate culture showed that about 95–98% of cultured microbes (P. corylophilum and A. niger) dominated in treated sludge after 2 days of treatment. In this study, it was also found that the P. corylophilum was capable of removing 94.40% of COD and 98.95% of turbidity of filtrate with minimum dose of inoculum of 10% v/v in DWTP sludge (1% w/w). The pH level was lower (acidic condition) in the fungal treatment and maximum reduction of COD and turbidity was observed (at lower pH). The results for specific resistance to filtration (SRF) showed that the fungi played a great role in enhancing the dewaterability and filterability. In particular, the strain Penicillium had a more significant capability (than A. niger) of reducing 93.20% of SRF compared to the uninoculated sample. Effective results were observed by using fungal inoculum after 2 days of treatment. The developed LSB process is a new biotechnological approach for sludge management strategy