Wastewater from lithium battery production?-Hezhong Environment (Beijing) Co., Ltd. was established in 2003

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Wastewater from lithium battery production?

Published Time:

2023-05-17

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Lithium-ion batteries, as a burgeoning new energy industry, are developing rapidly. However, this rapid development has also led to a massive increase in wastewater discharge from their production. Although China's lithium-ion battery production ranks first in the world, there is a lack of mature and effective treatment processes for wastewater from this industry. The overall treatment effect of lithium-ion battery production wastewater is not ideal, resulting in varying degrees of pollution and damage to the surrounding aquatic ecosystems of many lithium-ion battery production enterprises.

Sources and Characteristics of Wastewater from Lithium-ion Battery Production

1.1 Wastewater from the lithium-ion battery industry mainly consists of cathode and anode cleaning wastewater. The main pollutants are N-methyl-2-pyrrolidone (NMP), lithium cobaltate, carbon powder, and colloidal substances. The composition is complex, and it is poorly biodegradable. The characteristic pollutant N-methyl-2-pyrrolidone is a nitrogen-containing heterocyclic compound with a highly stable structure, making it difficult to biodegrade and exhibiting strong biotoxicity. Many lithium-ion battery manufacturers collect cathode and anode wastewater separately, and the treatment processes used after collection also differ.

1.2 Properties of Wastewater from Lithium-ion Battery Production

1.2.1 Large Fluctuations in Water Quality and Quantity

Due to the variability of lithium-ion battery production, the complexity of raw materials, intermittent wastewater discharge, and semi-automated production processes, precise water volume control is difficult during lithium-ion battery production, leading to significant fluctuations in wastewater quality and quantity.

1.2.2 Complex Water Quality and Poor Biodegradability

Wastewater from lithium-ion battery production is characterized by high COD and SS content, very low BOD5 content, a high content of pollutants that are somewhat biotoxic and difficult to biodegrade, and significant fluctuations in water quality and quantity. The chemical oxygen demand (COD) of this type of wastewater is above 2000 mg/L (calculated as CODcr), and the BOD/COD value is generally below 0.1, indicating extremely poor biodegradability. Conventional treatment processes are insufficient to achieve discharge standards.

Introduction to Wastewater Treatment Processes for Lithium-ion Battery Production

Currently, the treatment of wastewater from the production of new lithium-ion battery materials typically employs chemical oxidation decomposition, electrolysis, activated carbon adsorption, and reverse osmosis. Due to the increasingly stringent discharge standards for battery industry wastewater, a single process is insufficient to meet these standards. Combined processes must be used to meet the special discharge limits for water pollutants in Table 3 of the "Discharge Standard for Pollutants from the Battery Industry" (GB30484-2013).

Currently, the main wastewater treatment process in the lithium-ion battery industry is "pretreatment + biological treatment." After biological treatment, further advanced treatment methods are needed to achieve wastewater reuse or ensure that the effluent consistently meets standards. Common advanced treatment methods include activated carbon adsorption, membrane separation, ion exchange, dual membrane, and evaporation concentration. Typical treatment processes include: pretreatment + UASB + A/O tank + secondary sedimentation tank + evaporation concentration, coagulation sedimentation + UASB anaerobic reactor + A/O + secondary sedimentation, electrocoagulation + AAO + MBR + denitrification + nitrification + ultrafiltration + reverse osmosis.