Produced Water Filtration Treatment with Flat-Sheet Ultrafiltration Membrane Akolade Okunola *1, Hongbo Du1, Raghava R. Kommalapati1,2 1Center
for Energy & Environmental Sustainability (CEES) of Civil and Environmental Engineering Prairie View A&M University, Prairie View, TX 77429 2Department
Abstract
Objectives
Investigate the literature and identify ultrafiltration applications in PW treatment; Oil and gas extraction generates high volumes of wastewater from Characterize the organic matter content of PW using chemical fracturing and drilling. The Wastewater known as produced water oxygen demand (COD); (PW) contains both organic and inorganic contaminants. Due to strict Determine the effectiveness of ultrafiltration to treat PW. environmental regulations, it is important to treat PW before Methodology discharge to the environment or reuse. The goal of this current Determine COD of produced using HACH digestion colorimetric research is to improve the treatment process for PW using determination method 8000,with HACH DRB 200 reactor, and DR 3900 ultrafiltration which is a reliable process with high oil and suspended Spectrophotometer Instrument; solids removal rate. Suspended particles and residual oil present in Add distilled water to 2mL of PW sample A and B, stir; PW are removed with caustic soda softening , CO2 neutralization, and Use pipette to draw 2mL of diluted PW into each COD reagent Vials(A,B,C,D) for digestion; microfiltration . Then , PW is filtered using a flat-sheet Ultrafiltration Preheat the reactor to 150 oC, stir and clean the outside of the vials; membrane with a frequency drive for flow control. The membrane has Insert vials into the cell of the reactor and close the lid; a molecular weight cutoff of 100 Da. The UF system includes a CF042 After two hours , allow the vials to cool down for 20 minutes, stir and clean; test cell, a stainless-steel conical feed tank, a feed flow pump , a cell Safely take the reading using DR 3900 Spectrophotometer. platform containing system controls tubing , a chiller , a digital balance , and a computer to record data.PW before and after ultrafiltration is characterized by Chemical Oxygen Demand(COD).
Introduction
Produced water, by-product of shale oil & gas industry, contains high concentrations of salts, oil residues, fracking fluids and other chemicals; PW has very high hardness (more than 5000 mg/L commonly); According to American petroleum institute 206 million tons of PW was associated with a total crude oil production of 115.9 million tons;1 PW from oil and gas wells represents, by some estimates, the single largest source of waste generated in the United States;2 Ultrafiltration is a separation process using membranes with pore sizes in the range of 0.1 to 0.001 micron; Ultrafiltration is used for removal of high molecular-weight substances, colloidal materials, and organic and inorganic polymeric molecules.
Readings COD (PW after dilution) (mg/L) COD (PW) (mg/L)
Vial A
Vial B
Vial C
448
542
461
2240
2710
2305
Vial D 432 2160
Blanks 0 0
Figure 4. Produced water COD test vials color change.
Figure 2. Illusion of COD Test and Measurement
COD is one of very useful tools to measure PW characteristics; The literature shows that ultrafiltration can serve as an excellent process to pretreat shale oil & gas produced water.4
References
Figure 3. Color change after digestion
Results and Discussion
Figure 1. Ultrafiltration in produced water treatment.3
Table 1. Chemical Oxygen Demand of PW samples
1. United Kingdom Department of Trade and Industry, The Energy Report Oil and Gas Resources of the United Kingdom, 1997; 2. 2. Allen, D. T., & Rosselot, K. S. (1994). Pollution prevention at the macro scale: flows of wastes, industrial ecology and life cycle analyses. Waste Management, 14(3-4), 317-328. 3. Shang, W., Tiraferri, A., He, Q., Li, N., Chang, H., Liu, C., & Liu, B. (2019). Reuse of shale gas flowback and produced water: Effects of coagulation and adsorption on ultrafiltration, reverse osmosis combined process. Science of The Total Environment, 689, 47-56. 4. Chang, H., Li, T., Liu, B., Vidic, R. D., Elimelech, M., & Crittenden, J. C. (2019). Potential and implemented membrane-based technologies for the treatment and reuse of flowback and produced water from shale gas and oil plays: A review. Desalination, 455, 34-57.
The COD for PW sample was measured and it proved to be useful tool; The reagent chromate was reduced in proportion to the rate of organic water pollutant digestion; The sample color change from a light-yellowish brown to a darker Acknowledgements rust brown; R&I’s Office of Undergraduate Research (OUR) and Center for Energy The chromate was reduced and the organic matter in the PW were and Environmental Sustainability (CEES), Prairie View A&M University. oxidized.
This work is supported by the National Science Foundation (NSF) through the Center for Energy and Environmental Sustainability (CEES), an NSF CREST Center, Award #1036593.
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