The laboratory wastewater treatment system is a core facility essential for ensuring the safe operation of laboratories and preventing environmental pollution. Its design and operation must strictly match the complexity of the composition and fluctuating water quality of laboratory wastewater, while also complying with national and local environmental protection emission standards (such as the Comprehensive Wastewater Emission Standard GB 8978-1996, and the Technical Specification for Laboratory Wastewater Treatment, etc.). The following provides a detailed explanation of the system's core elements, treatment process, key technologies, design principles, and maintenance points to help understand its functionality and application.

Core treatment process of laboratory wastewater treatment system

The system typically follows a four-level process of "pre-treatment → main treatment → deep treatment → compliant discharge/reuse," with different processes for various types of wastewater, with the core principle being "first, collect by quality, then treat by category."

1: Quality Separated Collection (Preliminary Processing Requirement)

Core Objective: Prevent secondary pollution from the mixing of different types of wastewater (such as the exothermic reaction from mixing strong acid with strong alkali, and the formation of highly toxic HCN gas from cyanide wastewater and acidic wastewater), while also reducing the difficulty of subsequent treatment.

Implementation Method:

Dedicated waste water collection drums/pipes for laboratory use, labeled by "inorganic/organic/biological" categories, no mixing allowed.

Hazardous wastewater containing heavy metals, cyanides, etc., must be collected separately. Use "small mouth sealed drums + corrosion-resistant materials (PP/PTFE)" to prevent leakage.

Biological wastewater must undergo disinfection pretreatment before being connected to the collection system to prevent the spread of microorganisms.

2: Pretreatment (Reducing Pollutant Load)

Preliminarily remove "high-risk pollutants" from various types of wastewater to alleviate the subsequent main treatment process.

Inorganic wastewater pretreatment:

Acid-Base Neutralization: Adjust pH to 6-9 by using an automatic dosing unit (e.g., adding NaOH to neutralize acidic wastewater, adding H₂SO₄ to neutralize alkaline wastewater).

Heavy Metal Sedimentation: Add sulfides (e.g., Na₂S) or hydroxides (e.g., Ca(OH)₂) to precipitate heavy metal ions (e.g., PbS, Hg(OH)₂) as insoluble precipitates, and then separate them through the sedimentation tank.

Organic wastewater pretreatment:

Solvent Recovery: For high-concentration organic solvents, recovery and reuse through distillation/extracting (reducing processing costs, minimizing waste).

Oxidation Decomposition: For refractory organic matter (such as phenols), add an oxidant (such as H₂O₂, NaClO) or use the "Fenton Oxidation" process (Fe²⁺ + H₂O₂) to decompose large molecular organic matter into small, easily degradable substances.

Biological wastewater pretreatment:

Sterilization and Disinfection: Utilize "Chemical Disinfection" (effective chlorine concentration ≥50mg/L) or "Physical Disinfection" (UV radiation, dose ≥20000μW・s/cm²) to eliminate pathogenic microorganisms, preventing microbial proliferation that could block pipelines during subsequent processing.

3: Main Treatment (Core Pollutant Removal)

Select targeted technology based on wastewater type to ensure pollutant concentrations are reduced to nearly meet discharge standards.