1、 Where does secondary pollution come from

Foam entrainment and material loss (most common)

The waste liquid contains surfactant, brightener, cutting fluid emulsified oil, and the vacuum environment is easy to bubble. The foam flows into the condenser with heavy metals and organic matter droplets, and the heavy metals and COD in the condensate exceed the standard. At the same time, it pollutes the vacuum pump, causing secondary pollution; The lack of a foam removal net and defoaming structure in the equipment can easily lead to this problem.

Volatile substances overflow

Waste liquid contains strong volatile acids and some VOCs. Low temperature cannot completely suppress volatilization, and it will enter the condensate or vacuum pump exhaust gas, bringing corrosion and exhaust gas risks.

Improper management of concentrated solution

Evaporation only concentrates pollutants and cannot eliminate heavy metals and salts. The concentrated solution is classified as hazardous waste; If stored and leaked, or dumped indiscriminately, it can cause serious secondary pollution.

Equipment corrosion and leakage

Choosing the wrong material for high chloride ion waste liquid leads to corrosion and perforation of the cavity and seals, resulting in waste liquid leakage and pollution.

✅ By doing three things well, secondary pollution can be avoided: front-end pretreatment, equipment equipped with high-efficiency foam removal devices, and concentrated liquid handed over to qualified units for disposal.

2、 Is it feasible to meet emission standards

Feasible, but with the premise, it is recommended to prioritize the reuse of the condensate water workshop and not directly discharge it outside.

1. Under ideal conditions: After pre-treatment and equipment foam removal, heavy metals and salts in the condensed water are intercepted, and the water quality is good, which can be reused in the cleaning process.

2. Want to directly discharge to the outside world:

The electroplating industry needs to meet the "Emission Standards for Electroplating Pollutants GB21900-2008", and cannot only rely on laboratory data from equipment manufacturers, but also on the condensate water detection report after actual waste liquid small-scale testing.

In some scenarios, the COD and pH of the condensate water still fluctuate, and it is necessary to add activated carbon and perform deep treatment with simple biochemistry in the backend to ensure stable and compliant discharge.

3、 Practical selection reminder

1. Oil containing and highly foaming waste liquids must be pre treated with oil separation and filtration;

2. It is necessary to confirm the equipment configuration for foam removal/gas-liquid separation structure, which is the key to preventing material leakage;

3. High chloride ion waste liquid, titanium material is selected for the heat exchange components of the chamber;

4. Concentrated liquid must be stored and outsourced for disposal in accordance with hazardous waste regulations;

5. Prioritize sampling for small-scale testing, obtain actual measurement indicators of condensed water, and then determine whether to reuse or discharge.