Petrochemical Wastewater Treatment Project With CNPC
Thank you for your attention here, today we are going to share some data and information about a project we designed, constructed, and initialized operation in later 2024, and this team keep constant maintenance ever since, and hope that these datas will help you out when it comes to choosing the right technology for petrochemical wastewater treatment.
Wastewater Type: Petrochemical Wastewater
Operation: Dec. 2024
Treatment Goal: To realize on-site petrochemical wastewater treatment by removing the major content with complex compositions, especially highly concentrated organic pollutants, that the reducing the high COD, chemical oxygen demand value in the petrochemical wastewater generated within the petrochemical production process, that is to control CODcr, and restore the B/C ratio, to enable further treatment.
Refinery Petrochemical Wastewater Treatment Using Electrochemical Oxidation
1 Client Overview of Petrochemical Wastewater Treatment Project With CNPC
CNPC Shananxi is a branch of CNPC or China National Petroleum Corporation, located in Shaanxi Province, China, the CNPC Shananxi business operations covered the entire oil and gas value chain, that is start with oil exploration and production of finished products, natural gas, and crude oil refining and petrochemicals, engineering and marketing of the a wide variety of products.
CNPC Shananxi explores and develops oil and natural gas reserves in Ordos Basin, a highland sedimentary basin in parts of northernmost China which mainly covering Shaanxi, as well as Gansu, Ningxia, Inner Mongolia, and Shanxi province, that means exploration and extraction activities are basically conventional oil and natural gas sources instead of off-shore
Besides upstream crude oil and natural gas exploration in the Ordos Basin region, CNPC Shananxi also invloved in midstream and downstream operations such as, processing crude oil into finished products and manufactures a wide range of petrochemicals, and further marketing of finished products, petrochemicals, and non-oil products, as well as operating of gas stations which driectly serve domestic consumers.
Given its engineering and operation capability, CNPC Shananxi not only design and construct oil and natrual gas field facilities, but also build and operates pipelines and construction of storage facilities for both crude oil and finished oil products, erecting natrual gas pipelies and transportation facilities.
Staffs with CNPC Shananxi contacted Boromond team to seek technology solution for on-site petrochemical wastewater treatment as there are huge amount of petrochemical wastewater generated within growing exploration and petrochemical processing activities with the Shananxi branch and subsidiaries scatter in different locations.
Basic Information About CNPC Shananxi Petrochemical Wastewater Treatment Project
Industry: Petrochemical refinery (aromatic hydrocarbons)
Location: Shananxi, China
Flow: 4 m³/h (96 m³/day)
Composition Type: High-COD, biorefractory organics, phenols, benzene derivatives
2. The Challenge with CNPC Shananxi Petrochemical Wastewater Treatment Project
The CNPC Shananxi refinery’s existing biological treatment system was not able to degrade a wide range of organic pollutants, for instances, aromatic compounds like polynuclear aromatic hydrocarbons (PAHs), BTEX compounds (benzene, toluene, ethylbenzene, xylene), and phenolic compounds, these organic compounds are with high-molecular-weight and complex structures, causing:
COD levels >23000 mg/L in secondary effluent
Repeated failure to meet discharge limit COD < 300 mg/L
Odor complaints due to VOCs
High chemical cost for pre-treatment approach, for instance, Fenton
3. Project Objectives with CNPC Shananxi Petrochemical Wastewater Treatment Project
Reduce COD from a initial 23000 mg/L with the intaking effluents to less than 350 mg/L after further treatment and polishing
Break down recaltriant hydrocarbons and phenols
Downstream polishing and further treatment to reduce COD
Minimize chemical usage and sludge generation
4. Electro Oxidation Solution Implemented within CNPC Shananxi Petrochemical Wastewater Treatment Project
Technology: electrochemical oxidation was adopted as the main treatment technology since the project objectives are to reduce the COD by removing refractory organic pollutants, physical separation and filtration were arranged as pre-treatment prior to electrochemical oxidation processes to remove massive amount of oil and grease, suspended solids to prevent possible damage to the electrochemical oxidation reactors, followed by post-treatment such as adsorption and membrane separation for further polishing, to meet discharge compliances, and then water reuse.
Equipment: Electrochemical oxidation wastewater treatment modular unit Boromond MC175
Boromond engineering team managed to design a discontinuous cycle for this petrochemical wastewater treatment project after stimulating the treatment flow and analyzing data from the pre-treatment steps, the electrochemical oxidation wastewater treatment modular unit MC175 is modified to treat intermittent flow rate, and then the steps invloved filling of the single circular tank, and pumping into the core electrochemical oxidation reactor, electrochemical oxidation treating, settling after batch treatment, followed by discharging into the post-treatment processes, the last step was cleaning the electrochemical oxidation reactors, and resetting for the next batch.
Catalyst electrode material: boron doped diamond BDD electrode is adopted as anode within the electrochemical oxidation reactor , and this specific project were with boron doped diamond BDD anodes at surface area up to 42 square meters, all the BDD electrodes are fabricated, and tested by Boromond engineering team.
These modular electrochemical oxidation wastewater treatment units are designed to be erected vertically, which is a compact design to be installed in a limited area of 16 square meters, it’s out intention to minimize footprints as well as seeking possible expansion within existing treatment facilities, therefore realizing decentralized electrochemical oxidation solution with ease of operations, accomplishing treatment efficiency, and meeting treatment objectives, complying with environemtnal regulation.
Water Volume: designed to treatment intaking petrochemical wastewater from pre-electro oxidation processes at 4 m3 per hour, and a constant operation of 24 hours per day, which make the expected water volume up to 96 m3/d
Required Hydraulic Capacity: 4 m³/h
Contact Time within the electrochemical oxidation wastewater treatment system: 30–45 minutes total
Petrochemical wastewater treatment system design features:
Filter installed right after upstream effluents pumped into the electro oxidation system
Vertically installed electrolytic cells with advanced electrochemical oxidation module units
Automated controlling system
Automatic adjustment over major parameters
HMI-based real time monitoring and control system installed
5. Application of Electro Oxidation Wastewater Treatment Technology & Commissioning with CNPC Shananxi Petrochemical Wastewater Treatment Project
Skid-mounted electrochemical oxidation wastewater treatment modular unit installed without interrupting ongoing refinery operations
Integrated with existing equalization tank to hold effluents from upstream sedimentation, high performance filtration, and further treatment after electrochemical oxidation.
Start-up completed in 7 days
Optimization reduced chemical dosing by some 72%, chemicals added within the electro oxidation processes are Sodium sulfate/Na2SO4, Sodium chloride (NaCl), Sodium persulfate (Na2S2O8).
6. Results & Performance of Electro Oxidation with CNPC Shananxi Petrochemical Wastewater Treatment Project
Parameter Before Electro Oxidation After Electro Oxidation
COD 23,000 mg/L 16,100 mg/L
pH Value 3-5 – *no recording according to project logs
B/C Ratio <0.1 ≥0.25
Color Dark black Clearish
*this result is the result of the first electro oxidation wastewater treatment system within a customized sequential multiple electro oxidation systems, does not reflect the final results of the sequential electro oxidation treatment of several batches, actual results might be affected by real time current density, upstream effluent compositions, flow rate, treatment durations and etc, in this case, please contact Boromond team members to figure out how our electro oxidation wastewater treatment products, solutions and datas from previous projects help you out to tackle the challenges with your current and upcoming projects.
Additional Benefits of Electro Oxidation For Petrochemical Wastewater Treatment Project With CNPC
Biological treatment efficiency increased by 42%
This current electro oxidation are proven to improving the biodegradability of petrochemical wastewater to improving B/C ratio from a mere 0.1 to 0.25, by degrading complex, non-biodegradable organic compounds into smaller, less toxic, and more easily degradable organic compounds with smaller molecules, this team realized that there is a chance with introducing electro oxidaiton technology as a pre-treatment step to enhance the efficiency of subsequent biological treatment processes.
Electro oxdation can massively reduce a wide range of odors, odor-causing malodorous sulfur compounds like hydrogen sulfide and nitrogen compounds like ammonia, as shown in alteration of color of the blackish upstream effluents.
No or few sludge generate within the electro oxidation wastewater treatment processes, direct and indirect oxidation processes, that is direct mineralization or gradual degradation of complex organic compounds into less-complex organic compounds, and eventually inorganic matters, which means there is no bio-mass or masive sludge like traditional Fenton.
7. Client Testimonial of Electro Oxidation with CNPC Shananxi Petrochemical Wastewater Treatment Project
“We contacted Boromond team right afte we searched for new technology to treat petrochemical wastewater, and we told than that it’s better if all the systems can be installed within a limited space, as we had limited space for this current wastewater treatment plant, there were a lot of discussion and stimulation between our enineers and Boromond’s engineering team, and we are thrilled to know that they are capable of finish all the treatability and feasiblity studies, and then pilot testing with very limited time, and the electro oxidation was the first technology that consistently degraded our recalcitrant compounds from petrochemical wastewater. Compliance became predictable.” – JF Lee, Environmental Manager, CNPC SX
References, we are inspired by contents below, all the actional planning are down with enhancement of electro oxidation processes in mind:
Source 1: Nature, Application of electro oxidation process for treating wastewater from petrochemical with mixed metal oxide electrode
Source 2: ACS Electrochem. 2025, 1, 11, 2292–2316, view content on Electrochemical Advanced Oxidation Processes for Real Wastewater Remediation: Systems, Performance, and Generated Oxidants , from ACS Publications
