Sodium Battery Wastewater Treatment: Efficient Solid - Liquid Separation System
Introduction
Sodium batteries are an emerging category of new-energy power sources. Their production process generates Alkaline Wastewater that requires efficient solid–liquid separation to meet discharge or reuse standards. This document outlines a complete sedimentation and filtration system designed for treating sodium battery manufacturing wastewater, with a treatment capacity of 10 m³/h.
The system integrates chemical coagulation, lamella clarification, Sludge Dewatering, and polishing filtration to achieve an effluent total suspended solids (TSS) concentration of < 10 mg/L, starting from an influent TSS of < 100 mg/L.
Process Description
The treatment train follows a fully continuous flow scheme:
Wastewater Lifting – Raw effluent is pumped by submersible pumps into the chemical reaction tank.
Coagulation & Flocculation – PAC (polyaluminium chloride) and PAM (polyacrylamide) are dosed simultaneously via metering pumps into the reaction tank. An dual-agitation system ensures thorough mixing of chemicals with the wastewater.
Lamella Clarification – The chemically conditioned water flows by gravity into a lamella clarifier. Here, enhanced gravitational settling occurs due to inclined plate packs. The clarified supernatant overflows from the top weir into a supernatant holding tank.
Polishing Filtration – From the holding tank, a centrifugal pump delivers the supernatant to a cartridge-type precision filter for final removal of fine particulates. (An emergency recirculation line is also provided to return off-spec water back to the raw wastewater tank for reprocessing.)
Sludge Dewatering – Settled high-concentration slurry at the bottom of the lamella clarifier is extracted by pneumatic diaphragm pumps and fed into a filter press for further mechanical dewatering. The filtrate from the press is returned to the supernatant holding tank, while the dewatered cake is bagged for off-site disposal.
Key Equipment Specifications
| Item. | Equipment | Specification | Qty | Remarks |
|---|---|---|---|---|
| 1 | Filter Press | Plate-and-frame type, 1.5 kW | 1 set | For final sludge dewatering |
| 2 | Lamella Clarifier | Carbon steel with FRP anti-corrosion lining (three layers of glass cloth + five coats of resin), outlet DN80 | 1 unit | Alkali-resistant construction |
| 3 | Chemical Dosing Tanks | Dual-compartment type | 2 sets | For PAC and PAM preparation |
| 4 | Metering Pumps | Variable-frequency drive | 4 units | 2 operating + 2 standby |
| 5 | Reaction Tank | Dual agitators, elevated configuration | 1 unit | Ensures complete floc formation |
| 6 | Supernatant Holding Tank | PE, 5,000 L, with level sensor and valves | 1 unit | Buffer for downstream filtration |
| 7 | Flowmeter | Electromagnetic type, DN32 | 1 unit | Inline monitoring |
| 8 | Control System | PLC with HMI (touchscreen), industrial-grade components | 1 system | Includes control software; capable of integrating an external customer-supplied pump |
| 9 | Pneumatic Diaphragm Pumps | Aluminum body, PTFE seats, triple-rubber diaphragms and balls | 2 units | 1 operating + 1 standby |
| 10 | Precision Filter | 304 stainless steel housing with replaceable PP filter cartridges | 1 unit | Polishing step for guaranteed effluent quality |
| 11 | Centrifugal Pumps | Stainless steel construction, 12.5 m³/h @ 50 m head, 5.5 kW | 2 units | 1 operating + 1 standby |
| 12 | Steel Structural Platforms | Custom-fabricated | 2 units | For equipment access and support |
| 13 | Automation Components | Pneumatic valves, level probes, pressure switches | 1 set | For integrated filter-press automation |
| 14 | Piping & Valves | Complete interconnecting pipework and fittings | 1 lot | Covers up to 200 m from site utility points; no explosion-proof or special anti-corrosion requirements |
| 15 | Pressure Gauges | For all pumps | 1 lot | Local indication |
Design Features
Treatment Performance – Inlet TSS ≤ 100 mg/L → outlet TSS ≤ 10 mg/L. The precision filter serves as a final safety barrier to ensure consistent compliance.
Alkali Resistance – Both the lamella clarifier and the reaction tank are protected with a FRP lining (three plies of glass fabric + five resin coats) to withstand the caustic nature of the wastewater.
High Reliability – All pumps (metering, centrifugal, and diaphragm types) are configured with 100% standby redundancy (1 operating + 1 standby) to minimize production downtime, meeting the customer’s stringent uptime requirements.
Sludge Management – The integrated filter press produces a low-moisture cake for easy disposal, while all filtrate is recycled back into the process stream, achieving zero liquid waste from the dewatering step.
Layout & Installation
The system is designed with a compact footprint, featuring elevated reaction tanks and strategically placed steel platforms for maintenance access. Interconnecting piping and electrical cabling are kept within 200 m of the site interface points. No special explosion-proof or acid-proof ratings are required for ancillary components, as the system operates under ambient, non-hazardous conditions.
Control & Automation
The central control panel incorporates a Siemens PLC and touchscreen HMI, with all electrical components meeting or exceeding industrial-grade standards. The system provides:
- Automatic dosing control based on flow pacing.
- Level monitoring in the holding tank with interlocked pump start/stop.
- Pressure and flow alarms for filter and pump protection.
- A dedicated input for interfacing with an external customer-supplied wastewater lift pump, enabling fully coordinated start-up and shutdown sequences.
Conclusion
The sedimentation and filtration system offers a robust, scalable, and highly reliable solution for sodium battery wastewater treatment. By combining chemical coagulation, lamella clarification, and dual-stage filtration with full sludge dewatering, it ensures:
- Stable effluent quality (TSS < 10 mg/L).
- Long-term operational durability in alkaline conditions.
- Maximum production uptime through comprehensive pump redundancy.
- Minimal manual intervention via advanced automation.