Produced by metal wastewater, metal surface treatment industries in industrial parks, mines, and plating companies

Hello, I'm Minhee Hwang from the public relations office of ARK. Recently, there was a controversy in the news about the unauthorized discharge of metal wastewater in Incheon Industrial Complex.

In addition, in Yanggam-myeon, Hwaseong-si, where ARK is located, there was an accident in which wastewater discharge from a factory fire contaminated the 7.4-kilometer Hwaseong-Pyeongtaek River.

While wastewater must be discharged through proper treatment facilities, it is also closely related to the safety of the factory, and the causes of wastewater are not limited to the management of equipment and processes.

Let's talk about metallic wastewater.

Industries that generate metallic wastewater

Metallic wastewater can be generated from the following categories. The main constituents of wastewater can vary from industry to industry, and may contain non-biodegradable substances in addition to heavy metals.

Therefore, practitioners should be familiar with the main components of metallic wastewater and categorize the type of wastewater to find the appropriate treatment method.

Knowing the types of metallic wastewater is key

Wastewater can be categorized into acid-alkaline / cyanide / chromium as shown below. After analyzing the raw water, it is necessary to identify which type it belongs to for proper treatment. After proper treatment according to the type of wastewater, high concentration wastewater liquids that cannot be treated are treated as industrial waste. The surface treatment industry can obtain various advantages that the raw materials, steel and aluminum, do not have by treating them. These include corrosion and heat resistance.

Surface treatment technologies include surface polishing, etching, coating, deposition, hot-dip coating, coating, and lining, and various chemicals used in degreasing and cleaning processes result in the following types of wastewater.

Processes and inclusions in the metal surface treatment industry

The surface treatment of metals is the process of treating the surface to achieve a superior finish, and to achieve a smooth surface, the first process is degreasing and the second is pickling.

The materials used in these two stages are as follows: raw steel and aluminum, which are processed through various treatments, and the processed metal is distributed to various industries, including machinery, construction, automobiles, electronics, and plants.

Key Points for Analyzing Metallic Wastewater Source Water for Metal Surface Processors

As mentioned earlier, the treatment process for the same metal wastewater varies depending on the ‘wastewater system'. The composition after analyzing the raw water is important, and most of the metal wastewater is acid-alkaline wastewater with about 50%.

For successful wastewater treatment, it is important to determine whether the wastewater is acid-alkaline, nitrate-containing, or cyanide-chromium-containing.

The main treatment methods are pH adjustment and flocculation.

The above treatment process diagram may vary depending on the design of the environmental facility contractor. The powdered activated carbon injection facility aims to remove soluble COD and TOC substances, and the inclined plate sedimentation tank aims to remove SS substances with excellent sedimentation efficiency.

Please note that metal wastewater can be generated in various places such as surface treatment industry, electroplating industry, and zinc production mines, and wastewater containing various heavy metals may be generated due to surface cleaning by degreasing and acid cleaning, and melt coating.

RK Centrifugal Dehydrator : View