Fujian Nanping Desulfurization Wastewater Treatment Project

Project Background

Company Profile

Founded: 1958
Industry: Large state-owned enterprise integrating aluminum smelting and aluminum processing
Location: Nanping City, Fujian Province
Business Scope: Production, research and development, and deep processing of aluminum and aluminum alloy materials
Comprehensive Strength: At the forefront of China's aluminum industry
 

One of the top ten aluminum profile manufacturers in China
The only aluminum profile enterprise that simultaneously owns "China Famous Trademark", "China Famous Brand", "National Recognized Enterprise Technology Center", "National Torch Plan Key High-tech Enterprise", "National Innovative Enterprise" and other honors
Ministry of Industry and Information Technology's "Pilot Demonstration Enterprise for Integration of Informatization and Industrialization to Promote Energy Saving and Emission Reduction" and "Demonstration Enterprise for Industrial Brand Cultivation"
Second Prize of "Fujian Provincial Government Quality Award"
National "Quality Benchmark" enterprise

Production Scale

150,000 tons per year aluminum industry chain, covering prebaked anodes, electrolysis, casting (casting and rolling), processing (molds, aluminum profiles, aluminum plates and strips) and deep processing
Among them, the casting and processing capacities are both over 200,000 tons/year, and the main product is aluminum profiles
At present, the aluminum profile industry chain is at the forefront of the industry in terms of scale, brand building, technological innovation, standard setting, energy conservation and emission reduction, and management informatization

Company Status

One of the leaders in China's aluminum industry
With strong R&D capabilities, production capabilities and brand influence
Has made positive contributions to the development of China's aluminum industry

Challenges with Original Wastewater Treatment System

The original electrolytic aluminum flue gas desulfurization system was not equipped with a desulfurization wastewater treatment system. The desulfurization wastewater was fed into the sewage treatment system of the whole plant for comprehensive treatment and then discharged. Due to the high content of suspended matter and TDS in the desulfurization wastewater, it was difficult for the original sewage treatment of the whole plant. The system has a large impact. In order to meet the treatment requirements and reduce environmental risks, the company will build a desulfurization wastewater treatment system in the electrolytic aluminum flue gas desulfurization flue gas ultra-clean emission renovation project in 2022.

Project implementation

This project aimed to improve Fujian Nanping Aluminum's environmental protection by installing a new electrolytic flue gas desulfurization and purification system.

Project Highlights:

EPC Contractor: Yuanda Environmental Protection Engineering Co., Ltd. (State Power Investment Group)
Desulfurization Wastewater Treatment: Beijing Huade Chuangye Environmental Protection Equipment Co., Ltd. won the bid based on their expertise.
Project Timeline: Construction started in June 2022 and completed within 3 months (September 2022), meeting all design requirements.

Treatment Process:

• Raw Water Challenge: High fluoride content in the desulfurization wastewater.
• Emission Standard: The project aimed to meet the new standards (indirect emission limits) for fluoride content (≤5mg/L) as per Table 2 of GB25465-2010 "Aluminum Industry Pollutant Discharge Standards".
• Treatment System: A two-stage HDCY integrated desulfurization wastewater treatment system was designed by Beijing Huade Chuangye.

Stage 1:

1. Removes suspended solids (≤70ppm) using lime and integrated adsorption flocculant.
2. Pretreats fluoride (≤15mg/L).

Stage 2:

1. Removes fluoride further using fluoride removal agent and integrated adsorption flocculant.
2. Guarantees effluent fluoride content (≤5mg/L) and suspended solids (≤50mg/L).
3. Water Reuse: Treated clean water is reused in the factory or discharged externally.
4. Sludge Management: Sludge is dewatered and transported with desulfurized gypsum for comprehensive utilization.
5. This project demonstrates Fujian Nanping Aluminum's commitment to environmental protection by implementing advanced technology to meet stricter emission standards for fluoride in the desulfurization wastewater treatment process.

Process flow

HDCY system

The HDCY system is a two-stage process developed by Beijing Huade Chuangye Environmental Protection Equipment Co., Ltd. specifically for treating desulfurization wastewater.

Key Features:

• Integrates various water treatment technologies like coagulation, flocculation, and chelation sedimentation.
• Uses a single, specially formulated dry powder flocculant (dosage: 200ppm-300ppm) that simplifies the process and reduces costs.

Advantages of the flocculant:

• Neutral, inorganic, and environmentally friendly.
• Made from natural minerals with high adsorption capacity.
• Removes COD, total phosphorus, SS, fluoride, heavy metals, and other pollutants.
• Improves flocculation and sedimentation.
• Simplifies water quality control during process fluctuations.
• Renders settled heavy metals permanently harmless.

High-efficiency defluoridation agent:

• Composed of inorganic polymers with strong fluoride-chelating properties.
• Can be customized based on water quality.
• Utilizes electron cloud interaction to form strong bonds with fluoride ions.
• Achieves deep fluoride removal (below 1.0mg/L).

Overall Benefits:

1. Shorter reaction times due to single agent addition.
2. Faster settling and efficient rising water flow due to high-efficiency cyclone clarifier design.
3. Reduced power consumption and improved sludge dewatering efficiency.
4. Enhanced capture of fine particles in the clean water tank for stable effluent quality.
5. The HDCY system appears to be a robust and efficient solution for treating desulfurization wastewater, particularly when dealing with high fluoride content.

Core equipment list

Project Outcomes:

1. The operating conditions are stable and the impact resistance to fluctuations in suspended solids in the inlet water is strong. It can ensure that the inlet water SS is 0-100000mg/L, fluoride ≤200mg/L, and the outlet water SS≤50mg/L fluoride ≤50mg/L. Stable operation;
2. The quality of the effluent water is stable. After HDCY integrated desulfurization wastewater treatment, the overflow clean water stably meets the implementation requirements of the new standard (indirect emission limit) in Table 2 of GB25465-2010 "Aluminum Industry Pollutant Discharge Standard";
3. The pharmaceutical system is simple, the process is simplified, and the entire process runs automatically without human intervention;
4. The underflow sludge does not need to be treated separately and is directly pumped to the gypsum dehydration system to complete dehydration, simplifying the process and improving operation reliability.