A New Approach to Coal Chemical Wastewater Treatment: From "End-of-Pipe Treatment" to "Full-Process Resource Utilization"

Coal chemical wastewater is complex in composition, highly polluting, and difficult to degrade. Traditional treatment approaches, aiming for "compliant discharge," face challenges such as high costs, high energy consumption, difficulties in handling mixed salts, and challenges in achieving sustainable compliance. Under the new circumstances, achieving green and low-carbon transformation and the goal of "zero emissions" requires breaking through traditional concepts and exploring new approaches to wastewater treatment that are comprehensive, resource-based, and intelligent.

I. Source Reduction and Process Control

Clean Production and Process Optimization

Optimize process parameters for coal gasification, washing, and cooling to reduce wastewater generation.

Promote closed-loop recycling and differentiated reuse to reduce fresh water consumption.

Graded Collection and Differentiated Treatment

Collect and treat wastewater according to its quality (high phenols, high ammonia nitrogen, high salinity, etc.) to improve treatment efficiency and reduce treatment difficulty.

Advantages: Reduces end-of-pipe treatment load, saves operating costs, and improves system resilience.

II. High-Efficiency Pretreatment and Toxicity Reduction

Enhanced Physicochemical Pretreatment

High-efficiency flotation and coagulation sedimentation to remove oil, suspended solids, and some colloids.

Advanced oxidation (ozone catalytic oxidation, Fenton oxidation, electrochemical oxidation, etc.) pretreatment to degrade toxicity and improve biodegradability.

Recovery of Valuable Substances such as Phenols and Ammonia

Recover phenols and ammonia nitrogen from wastewater through solvent extraction and stripping, turning waste into valuable resources and reducing subsequent treatment pressure.

Recovered products can be reused as chemical raw materials.

Advantages: Reduces the impact on subsequent biological treatment systems, improves overall treatment efficiency, and achieves resource recovery.

III. Innovation and Enhancement of Biological Treatment Technology

High-Efficiency Biological Treatment Processes

Utilizes toxic-resistant, salt-resistant, and highly efficient degrading bacteria, enhancing A/O, A²/O, SBR, and MBBR processes to improve COD and ammonia nitrogen removal efficiency.

Combined anaerobic-aerobic processes degrade macromolecular organic matter, generating biogas energy.

Biofortification and Microbial Agent Dosing

Addition of specialized, highly efficient degrading microbial agents enhances the system's ability to degrade recalcitrant organic matter (such as polycyclic aromatic hydrocarbons and heterocyclic compounds).

Advantages: Improves the biological system's resistance to shock loads, ensures stable operation, and reduces sludge production.

IV. Deep Treatment and Resource Reuse

Membrane Separation and Advanced Oxidation Deep Treatment

Ultrafiltration, reverse osmosis, and other membrane technologies for deep purification, achieving improved water quality.

Advanced oxidation technologies (ozone catalytic oxidation, photocatalytic oxidation, etc.) deeply remove recalcitrant organic matter, ensuring the quality of reclaimed water.

Salt Separation Crystallization and Resource Utilization of Impure Salts

Utilizing fractional crystallization and salt-separation crystallization technologies, inorganic salts in wastewater are separated into industrial-grade sodium chloride, sodium sulfate, and other products, achieving salt resource recovery.

This avoids the challenges of hazardous waste disposal of impure salts, generating economic benefits.

Zero Discharge of Wastewater and Water Reuse

The treated water is reused for circulating cooling, process water, etc., maximizing water resource reuse rates.

Advantages: Achieves zero discharge requirements, realizing dual recovery of water and salt resources.

V. Intelligent and Smart Operation and Maintenance

Intelligent Monitoring and Big Data Optimization

Utilizing IoT, online monitoring, big data, and artificial intelligence technologies, key water quality, equipment status, and operating parameters are monitored and intelligently controlled in real time.

This enables early warning, optimized chemical dosing, and energy-saving operation, improving management efficiency and system stability.

Remote Operation and Maintenance and Automated Management

Establishing a smart water management platform enables remote diagnosis and optimization, reducing labor and operation and maintenance costs.

Advantages: Improves system adaptability and operational reliability, reducing energy and chemical consumption.

VI. Circular Economy and Industrial Park Collaborative Governance

Enterprise-Industry-Regional Collaborative Governance

Collaborating with other enterprises in the park, centralized wastewater treatment and resource recovery are achieved, realizing cascaded energy utilization and co-processing of waste salt and sludge.

Wastewater Treatment and Carbon Reduction Synergy

Combining biogas power generation, energy-saving equipment, and green processes, low-carbon wastewater treatment is achieved, contributing to the "dual carbon" goal.

Advantages: Reduced treatment costs, achieving a win-win situation for environmental protection and economic benefits.

VII. Typical Cases and Achievements (Reference Information Combined)

• Guoneng Yulin Chemical: Salt separation and crystallization technology achieves resource recovery of mixed salts, "zero discharge" of wastewater, and reuse of produced water and industrial salt.

• Shaanxi Coal Group Project: Combining advanced oxidation + high-efficiency biochemical treatment + membrane separation to achieve stable compliance and reuse of high-COD and high-phenol wastewater.

• Smart Water Application: Big data platform optimizes operation, improves treatment efficiency, and reduces energy consumption and operation and maintenance costs.

VIII. Future Outlook

• Technological Innovation: Developing low-energy membranes, high-efficiency catalysts, intelligent equipment, etc., to improve treatment efficiency and resource recovery levels.

• Policy Guidance and Standards Improvement: Promote policies for wastewater resource utilization and zero discharge, and improve the standards system.

• Social Participation: Enterprises fulfill their responsibilities, the public participates in supervision, and jointly promotes green development.

Conclusion: The new approach to coal chemical wastewater treatment emphasizes source reduction, process control, toxicity reduction, resource recovery, intelligent operation and maintenance, and cyclical synergy, realizing the transformation of wastewater treatment from a "burden" to a "value creation." In the future, with technological advancements and updated concepts, coal chemical wastewater will no longer be an environmental burden, but a new driving force for enterprises' green transformation and sustainable development.