China's Current Environmental Protection Policies and Full Compliance Control Requirements for Injection Molding Production
Injection molding is a core segment of China’s plastic processing industry, generating volatile organic compounds (VOCs), production wastewater, plastic solid waste and equipment noise during melting, crushing and mold cleaning. All manufacturers must comply with a complete legal system, national mandatory standards and pollutant supervision rules issued by the Ministry of Ecology and Environment of China. Non-compliance will result in fines, production suspension or even criminal liability. This article systematically sorts out full-process environmental access rules, pollutant treatment standards and daily compliance management norms applicable to domestic injection molding plants.
1. Pre-production Access & Discharge Permit Policies
Newly-built, expanded or reconstructed injection molding production lines must complete environmental impact assessment (EIA) filing or approval before construction, implementing the “three-simultaneous” rule that pollution treatment facilities are designed, constructed and operated alongside main production equipment. Small-scale workshops using only virgin PP/PE pellets with annual output below 10,000 tons only need online pollution discharge registration. Factories producing over 10,000 tons annually, or processing ABS, PC, PVC and recycled plastics, must submit a formal EIA report and obtain official approval.
Under the Regulations on the Administration of Pollutant Discharge Permits, enterprises fall into two management categories. Large-scale molding factories adopt simplified permit management and must apply for official discharge permits, complying with specified emission limits and fixed monitoring frequencies. Small micro-factories only complete online registration but are still required to install complete pollution control equipment. All permit holders shall follow HJ1122-2020 technical specifications to maintain daily operation logs, conduct self-monitoring and submit annual compliance reports; incomplete file records will trigger official inspections and penalties.
2. Mandatory Control Standards for Waste Gas
VOCs and particulate matter from plastic melting and crushing are governed by GB31572-2015 (2024 Amendment) Emission Standard of Pollutants for Synthetic Resin Industry, and unorganized emission activities follow GB37822-2019 Standard for Unorganized Emission Control of Volatile Organic Compounds. The organized non-methane total hydrocarbon limit stands at 100mg/m³, with exhaust stacks no shorter than 15 meters; the boundary unorganized limit is 4.0mg/m³, while odor concentration complies with GB14554-93.
All injection machines, mixers and crushers must be fully sealed with closed gas collection hoods to avoid open-air production. Low-concentration waste gas applies bag dust removal plus two-stage activated carbon adsorption, with activated carbon iodine value no less than 800mg/g and gas residence time over 1.5 seconds. Large continuous-production factories adopt zeolite rotary wheel catalytic combustion with treatment efficiency above 90%. Spent activated carbon belongs to HW49 hazardous waste, stored in dedicated anti-seepage warehouses and transferred by qualified disposal companies with unified hazardous waste delivery forms.
3. Wastewater Separation & Discharge Specifications
All molding workshops implement strict rainwater and sewage separation. Production floors, raw material storage areas and hazardous waste warehouses are paved with anti-seepage concrete with independent drainage channels to prevent mixing of rainwater and polluted wastewater. Circulating cooling water from injection machines is recycled in cooling towers without external discharge. Oil-containing wastewater from mold cleaning and equipment wiping flows into oil separation sedimentation tanks to remove floating oil and suspended solids before entering municipal sewage pipelines, meeting Grade 3 limits of GB8978-1996 Integrated Wastewater Discharge Standard. Oil sludge cleaned from sedimentation tanks is classified as hazardous waste and forbidden to be disposed with domestic garbage.
4. Classified Management of Solid Waste
Sprues, leftover plastic scraps and qualified crushed materials belong to general industrial solid waste, stored in closed anti-dust zones on anti-seepage ground. Internal recycling is prioritized; external sales require complete transfer records and recycler qualification documents. Waste plastic packaging and ordinary wiping cloths are delivered to regular industrial waste recyclers instead of open-air stacking.
Waste hydraulic oil, mold cleaning solvent, oil-contaminated rags and spent activated carbon are defined as hazardous waste under the National Hazardous Waste Catalogue (2025 Edition). Independent anti-seepage hazardous waste warehouses with clear warning signs must be built, equipped with oil-absorbing felts and emergency collection barrels. Hazardous waste storage shall not exceed one year, and full transfer documents must be retained for at least five years.
5. Noise Control & Daily Compliance Supervision
Noise generated by injection machines, crushers and chillers must comply with GB12348-2008 Standard for Environmental Noise at Factory Boundaries. Equipment is installed in sound-insulated rooms with shock-absorbing pads and silencers. Factories located in industrial zones follow Category 3 limits (day ≤65dB, night ≤55dB), while plants adjacent to residential areas implement stricter Category 2 standards. High-noise crushing and debugging operations are restricted between 22:00 and 06:00 to avoid public complaints.
Enterprises must establish complete environmental management archives covering raw material consumption records, waste gas filter replacement logs, hazardous waste inbound and outbound forms, wastewater tank cleaning records and third-party testing reports. Ecological departments carry out regular random inspections; enterprises with excessive emissions, concealed discharge or incomplete archives will face heavy fines and ordered production rectification.
Conclusion
China’s environmental governance system for injection molding covers pre-production approval, end-of-pipe pollutant treatment, solid waste classification and long-term file supervision, with core national standards focusing on VOC closed collection, hazardous waste standardized storage and rain-sewage separation. Full compliance relies on source emission reduction, closed process control, efficient terminal treatment and complete traceable archives. Strictly implementing all above policies and standards helps molding factories eliminate compliance risks, reduce environmental penalties and realize green low-carbon manufacturing under China’s dual-carbon strategy.
