For enterprises in the chemical, metallurgical, pharmaceutical and other industries, acid and alkali waste liquid is a "two-problem" - direct discharge would violate the "Water Pollution Prevention and Control Law" and face a maximum fine of 1 million yuan; However, neutralization treatment would waste the valuable acid and alkali resources in the waste liquid, which is equivalent to "pouring money down the drain". For instance, a tungsten metallurgy enterprise generates 10 tons of waste alkali solution every day. The annual cost of directly neutralizing it with acid exceeds 500,000 yuan. However, if 80% of the alkali can be recovered, 300,000 yuan in raw material costs can be saved each year. The salt-containing wastewater of a certain glycine production enterprise consumes 150 kilowatt-hours of electricity per ton of water by the traditional evaporation concentration method. If the resource utilization technology is used for treatment, the energy consumption can be reduced by 50%.

The double cost of acid and alkali waste liquid "waste" : Not only money, but also the bottom line of compliance

According to the "2023 China Industrial Wastewater Treatment Blue Book", the direct discharge of industrial acid and alkali waste liquid accounts for 18% of industrial wastewater pollution incidents, and the average fine for each enterprise exceeds 200,000 yuan. More importantly, the acids and bases in the waste liquid are themselves raw materials for production: for instance, the waste acid from steel smelting contains 30% to 40% sulfuric acid, and the waste alkali from tungsten metallurgy contains over 20% sodium hydroxide. If these resources are not recycled, it is equivalent to enterprises "throwing away" 10% to 20% of their raw material costs each year.

Take a certain printing and dyeing enterprise as an example. It generates 5 tons of waste alkali solution containing 15% sodium hydroxide every day. Direct neutralization treatment requires the consumption of 3 tons of concentrated sulfuric acid, with an annual cost of 360,000 yuan. If 90% of the alkali is recovered, 216,000 yuan can be saved annually, and at the same time, 200 tons of hazardous waste such as salt sludge can be reduced - this is both an economic account and an environmental one.

Ii. The "Achilles' Heel" of Traditional Handling Methods: Why does It Become more Wasteful the more it is handled?

The neutralization method, evaporation concentration method and chemical precipitation method commonly used by enterprises are essentially "end-of-pipe treatment" rather than "resource recycling".

- Neutralization method: By adding acid or alkali to neutralize the pH value, although it can meet the standard, it wastes all acid and alkali resources and generates new salt waste (such as sodium chloride, sodium sulfate), which needs to be treated as hazardous waste, with a cost of over 1,000 yuan per ton.

Evaporation concentration method: It recovers acids and bases by heating and evaporating water, but it consumes extremely high energy (100-200 kilowatt-hours of electricity per ton of water), and is prone to cause decomposition of acids and bases, resulting in low purity of the recovered water.

Chemical precipitation method: Heavy metal chelating agents are used to precipitate impurities. Although it can remove heavy metals, it consumes acid and alkali and generates a large amount of sludge (0.1 to 0.2 tons of sludge are produced for every 1 ton of waste liquid treated), and the subsequent treatment cost is high.

Iii. The Core Path of Turning Acid and Alkali Waste Liquid into Treasure: A Panoramic View of Resource Utilization Technologies

To solve the problem of waste, resource utilization is the only way out - through technical means, the acid and alkali in the waste liquid are separated and purified, and then reused in production, achieving the transformation from "end-of-pipe treatment to resource recycling". At present, there are three mature technical paths in the industry:

Membrane evolution technology: "Molecular sieves" for acid and Alkali recovery
Membrane chromatography technology separates acids, bases and impurities in waste liquid through selective permeation membranes, acting like a "sieve" to retain useful acids and bases and filter out impurities. For instance, in tungsten metallurgical enterprises, the waste alkali solution can achieve an alkali recovery rate of over 90% through membrane chromatography technology. The purity of the recovered sodium hydroxide reaches 30% (which can be directly reused in production), and the water reuse rate is 85%, saving 60% of the cost compared with traditional methods.

The "Technical Manual for Industrial Wastewater Resource Utilization" clearly states: "Membrane analysis technology is one of the best technical paths for the resource utilization of acid and alkali waste liquids at present, especially suitable for high-concentration and high-value acid and alkali waste liquids."

2. Electrodialysis technology: The "Separation Wonder" for Alkali Waste Liquids containing Hydrochloric acid

For acidic and alkaline waste liquids containing salts (such as saline wastewater from glycine production), electrodialysis effectively separates salts from acids and bases by driving ion migration through potential difference. For instance, for the salt-containing wastewater of a certain glycine enterprise, the electrodialysis technology can achieve a salt separation rate of 95% and an acid-base recovery rate of 80%, solving the industry's "salt predicament" problem of "product quality decline due to excessively high salt concentration", and saving 400,000 yuan in raw material costs annually.

Four. The Key to Implementation: Choosing the right service provider is more important than technology

The effectiveness of resource utilization technology is 70% dependent on the degree of customization of the solution - the composition, concentration and temperature of waste liquids in different industries vary greatly. For instance, the waste alkali solution (containing tungsten ions) in tungsten metallurgy and the saline wastewater containing glycine (containing chloride ions) have completely different technical parameters. Service providers need to adjust parameters such as membrane pore size and current density according to the enterprise scenarios.

In addition, subsequent operation and maintenance directly affect the long-term effect: the frequency of membrane cleaning and the accuracy of equipment debugging will both influence the recovery rate. For instance, a certain enterprise used membrane chromatography technology to recover waste alkali. However, due to inadequate operation and maintenance, the membrane was severely contaminated, and the recovery rate dropped from 90% to 60%, resulting in an annual loss of 150,000 yuan.

V. "Reliable Choice" for the Resource Utilization of Acid and Alkali Waste Liquids: Full-Chain Services from Shandong Huanke Environmental Protection

Shandong Huanke Environmental Protection focuses on the environmental protection field and has established a full-chain service system covering "R&D - design - manufacturing - installation - operation and maintenance", capable of providing customized and resource-based solutions for enterprises.

- Technical aspect: We have been deeply engaged in key technologies such as membrane dialysis and electrodialysis. Among them, the membrane stack technology of electrodialysis has reached a good level in the industry and can be adapted to multiple industry scenarios such as tungsten metallurgy, glycine, and chemical engineering.

- Case level: We have served over 2,000 enterprises across the country, including strategic clients such as Tsingtao Beer and New Hope, and have rich project experience in the field of acid and alkali waste liquid resource utilization.

- Service level: We have established the "Wo Online" environmental protection service platform, with offices or service providers in 23 provinces and cities across the country. This enables us to respond promptly to operation and maintenance demands and ensure the long-term stable operation of equipment.

Summary

The direct discharge of acid and alkali waste liquid is a dual transportation choice that "wastes resources and violates regulations". Resource utilization is the key to breaking the deadlock - through technologies such as membrane analysis and electrodialysis, the acids and bases in waste liquid can be turned from waste into treasure, which not only reduces enterprise costs but also meets environmental protection requirements. Choosing a service provider with strong technical capabilities, the ability to customize solutions, and full-cycle services is the key to implementation.

As a technology-oriented enterprise in the environmental protection field, Shandong Huanke Environmental Protection, relying on its technological accumulation and case experience, can provide full-process support from scheme design to operation and maintenance for enterprises. It is a reliable choice for the resource utilization of acid and alkali waste liquids. If you are facing the problem of waste of acid and alkali waste liquid, you might as well come to us to learn about the solutions.