General components of wastewater treatment system in Nanjing Wastewater Treatment Laboratory

A complete laboratory wastewater treatment system generally has 8 components:

1. Collection box

A liquid level automatic control system is set in the adjustment tank. When the amount of wastewater reaches a certain amount, the sewage treatment system will run automatically. At the same time, it can realize the self-neutralization of sewage with different properties in different time periods and reduce the use of acid-base neutralizing agents.

2. Acid-base neutralization system

Since the sewage contains acids, alkalis and inorganic salts, it is necessary to conduct acid-base neutralization treatment on the wastewater. The pH controller is used in the acid-base neutralization tank, and a certain amount of NaOH aqueous solution is accurately added using a metering pump to adjust the pH value to between 8 and 9. Under alkaline conditions, the acid in the wastewater is neutralized, iron, cadmium, copper , manganese, nickel, lead, chromium and other heavy metal ions react with OH- to form hydroxide precipitation.

3. Sedimentation tank

After the sewage is treated by the acid-base neutralization adjustment system, part of the dissolved substances will form precipitation, and the precipitation together with the original suspended substances in the sewage will realize the separation of mud and water in the sedimentation tank, fully realize the separation of mud and water, and ensure that the suspended solids index reaches the standard.

4. Disinfection and oxidation pool

Since the sewage of this project is generated during the detection process, the sewage contains a certain amount of pathogenic microorganisms. In this plan, an oxidation tank is set up and ozone is added to kill the pathogenic microorganisms in the water.

5. Active adsorption device

The sterilized wastewater then enters the active adsorption device, and some of the fine suspended solids, trace metals and a very small amount of organic matter that have not been removed are removed by physical and chemical actions such as adsorption and retention, and the other is attached to the adsorbent. The anaerobic, aerobic and facultative bacteria in the microbial membrane on the filter material are degraded and removed, and the activated carbon intercepts and adsorbs, and the process of microbial degradation and desorption is interspersed, alternated and circulated. So far, the wastewater can be discharged up to the standard.

6. Heavy metal capture system

The heavy metal capture system is a strong capture of heavy metal ions, because it can be in the normal temperature and a wide range of PH value conditions, and various heavy metal ions such as Cu2+, Cd2+, Hg2+, Pb2+, Mn2+, Ni2+, Zn2+, Cr3+ in wastewater. Carry out the capture reaction, and quickly remove heavy metal ions in a short time, so as to achieve the removal of heavy metal ions in water.

7. Low-voltage micro-electrolysis system

The low-voltage micro-electrolysis system uses the potential difference between the ions in the wastewater and the micro-electrolysis device to form countless tiny galvanic cells. These tiny batteries use low-potential iron as the anode and high-potential carbon as the cathode, and electrochemical reactions take place in an aqueous solution containing an acidic electrolyte. Nanjing wastewater comprehensive treatment equipment.

8. Photocatalytic reaction system

The photocatalytic reaction system utilizes the ionic reaction between light and the carrier. When the light with the photon energy higher than the absorption threshold of the semiconductor irradiates the semiconductor, the valence band electrons of the semiconductor undergo interband transitions, that is, from the valence band to the conduction band, resulting in Photogenerated electrons (e-) and holes (h+). At this time, the dissolved oxygen adsorbed on the surface of the nanoparticles captures electrons to form superoxide negative ions, while the holes oxidize the hydroxide ions and water adsorbed on the surface of the catalyst to hydroxyl radicals. The superoxide anion and hydroxyl radical have strong oxidizing properties, which can oxidize most organic substances to the final products CO2 and H2O, and even completely decompose some inorganic substances.