When it comes to heavy metals, everyone is quite familiar with them, such as iron, copper, silver and aluminium, which we often hear about. So where do heavy metal wastewater mainly come from? Why is it necessary to conduct 24-hour real-time monitoring of it? This chapter will explore together with everyone the issues related to the monitoring of various parameters of heavy metals in water.

There are many sources of heavy metal wastewater, such as the washing water of electroplated parts in electroplating factories, the drainage in mine pits, the acid washing drainage in steel mills, and the wastewater from paint and pigment production, all of which contain heavy metals. If a large amount of heavy metal wastewater is directly discharged into rivers, lakes, streams and other water sources without treatment and monitoring, it will cause water pollution. Common treatment methods for heavy metal wastewater include electrochemical methods, adsorption methods, and chemical precipitation methods, among others. After treatment, the heavy metal indicators in the water can be monitored in real time through a water quality detector to see if there is any over-standard situation. The purpose of conducting 24-hour real-time monitoring is to determine the changes in water quality through multiple data comparisons.

It should also be noted that in the sewage of our daily life, the designed indicators are for some conventional parameters such as low concentration COD (Chemical Oxygen Demand), ammonia nitrogen, BOD (Biological Oxygen Demand), total phosphorus, and total nitrogen. However, the treatment of total metal wastewater is rather complex and usually requires strong acid and strong alkali auxiliary monitoring, which will affect the pH value. So for domestic sewage, it is generally not considered to monitor the content of heavy metals in the water.