What are the types of industrial wastewater? How to effectively handle it?

Industrial wastewater refers to the wastewater, sewage, and waste liquid generated in the industrial production process, which contains industrial production materials, intermediate products, and products lost with water, as well as pollutants generated during the production process. With the rapid development of industry, the types and quantities of wastewater are rapidly increasing, and the pollution of water bodies is becoming increasingly widespread and serious, posing a threat to human health and safety. For environmental protection, the treatment of industrial wastewater is more important than the treatment of urban sewage. Beijing Elmes wastewater treatment experts suggest designing wastewater treatment plans based on different water quality categories and establishing a comprehensive industrial wastewater reuse system, which greatly saves labor and material losses, enabling industrial enterprises to achieve a green industry with zero emissions in the future.

Industrial wastewater classification

There are usually three types:

Classification is based on the products and processing objects of industrial enterprises, such as metal smelting wastewater, papermaking wastewater, tannery wastewater, metal pickling wastewater, paint spraying wastewater, coking gas wastewater, chemical fertilizer wastewater, textile printing and dyeing wastewater, printing and dyeing wastewater, pesticide wastewater, power plant wastewater, etc.

The second type is classified according to the chemical properties of the main pollutants contained in industrial wastewater. Inorganic wastewater is mainly composed of inorganic pollutants, while organic wastewater is mainly composed of organic pollutants. For example, electroplating wastewater and mineral processing wastewater are inorganic wastewater; Wastewater from food or petroleum processing is organic wastewater.

The third type is classified according to the main components of pollutants contained in wastewater, such as acidic wastewater, alkaline wastewater, cyanide wastewater, chromium wastewater, cadmium wastewater, mercury wastewater, phenol wastewater, aldehyde wastewater, oil containing wastewater, sulfur containing wastewater, organic phosphorus wastewater, and radioactive wastewater. The first two classification methods do not involve the main components of pollutants contained in wastewater, nor do they indicate the harmfulness of wastewater. The third classification method, which clearly identifies the main pollutants in wastewater, can indicate a certain degree of harm to the wastewater.

In addition, starting from the difficulty of wastewater treatment and the harm of wastewater, the main pollutants in wastewater are classified into three categories: waste heat, mainly from cooling water, which can be reused; The second category is conventional pollutants, which are substances that have no obvious toxicity but are easily biodegradable, including biodegradable organic matter, compounds that can be used as biological nutrients, and suspended solids; The third category is toxic pollutants, which contain substances that are toxic but not easily biodegradable, including heavy metals, toxic compounds, and organic compounds that are not easily biodegradable. Beijing Elmes Company distinguishes wastewater based on this type and designs wastewater treatment plans with different processes. (Click to enter the Industrial Purification System interface to learn more detailed wastewater treatment processes)

In fact, an industry can discharge several types of wastewater with different properties, and a type of wastewater will have different pollutants and pollution effects. For example, dye factories discharge both acidic and alkaline wastewater. Due to the differences between fabrics and dyes, the pollutants and pollution effects in textile printing and dyeing wastewater can vary greatly. Even the wastewater discharged from a production unit may contain several pollutants at the same time. The overhead oil vapor condensate of distillation, cracking, coking, stacking and other devices in oil refineries contains phenols, oils, and sulfides. In different industrial enterprises, although products, raw materials, and processing processes are completely different, wastewater with similar properties may also be discharged. Oily and phenolic wastewater may be discharged from refineries, chemical plants, and coking gas plants.

Handling principles

The effective treatment of industrial wastewater should follow the following principles:

① The fundamental goal is to reform the production process and eliminate the generation of toxic and harmful wastewater as much as possible during the production process. If non-toxic materials or products are used to replace toxic materials or products.

② In the production process of using toxic raw materials and producing toxic intermediate products and products, reasonable process flow and equipment should be adopted, and strict operation and supervision should be implemented to eliminate leakage and minimize the amount of loss.

③ Wastewater containing highly toxic substances, such as heavy metals, radioactive substances, high concentrations of phenols, cyanide, etc., should be separated from other wastewater to facilitate the treatment and recovery of useful substances.

④ Some wastewater with high flow rate and light pollution, such as cooling wastewater, should not be discharged into the sewer to avoid increasing the load on urban sewers and sewage treatment plants. This type of wastewater should be properly treated and reused in the factory.

⑤ Organic wastewater with components and properties similar to urban sewage, such as papermaking wastewater, sugar making wastewater, food processing wastewater, etc., can be discharged into urban sewage systems. Large sewage treatment plants should be built, including simple and feasible treatment facilities such as biological oxidation ponds, sewage reservoirs, and land treatment systems that are tailored to local conditions. Compared with small sewage treatment plants, large sewage treatment plants can significantly reduce basic construction and operating costs, while maintaining good operating conditions and treatment effects due to stable water volume and quality.

⑥ Some toxic wastewater that can be biodegradable, such as phenol and cyanide wastewater, can be treated in the factory and discharged into urban sewers according to allowable discharge standards, and further treated by the sewage treatment plant for biological oxidation and degradation.

⑦ Wastewater containing toxic pollutants that are difficult to biodegrade should not be discharged into urban sewers or transported to sewage treatment plants, but should be treated separately.

Development Trends

In the context of the increasing shortage of water and other resources and the urgent need for environmental pollution control, the development trend of industrial wastewater treatment is to recycle water and pollutants as useful resources and implement closed-loop circulation. This can be divided into comprehensive recycling of water and pollutants. Water and pollutants are recycled separately. Therefore, in the future, the water treatment industry must master the reaction principle of wastewater treatment, and must have rich chemical knowledge in order to thoroughly understand the operation status of wastewater treatment equipment, achieve effective utilization of materials instead of extravagance and waste, and achieve the possibility of zero discharge of wastewater.

The above is what Hongjie Water brings to everyone about "What are the types of industrial wastewater and how can they be effectively treated?" We hope it can help you!

Shenzhen Hongjie Water Technology Co., Ltd. is an integrated high-tech enterprise specializing in product research and development, production, sales, engineering design, installation and debugging, technical consulting, and sales of supporting materials in the fields of industrial water treatment and drinking water treatment. Our main products include the design, manufacturing, installation, debugging, and maintenance of water treatment equipment, including pure water equipment, ultra pure water equipment, reverse osmosis equipment, GMP purified water equipment, EDI deionized water equipment, domestic sewage equipment, industrial wastewater equipment, softened water equipment, and reclaimed water reuse equipment, all of which are integrated into an environmentally friendly high-tech manufacturer.