Key Parameters for Brewery Wastewater Discharge

The Chinese brewing industry is a major segment of the national food sector. On January 1, 2026, the new Discharge Standard of Water Pollutants for Fermented Alcohol and Alcoholic Manufacturing Industry (GB 19821-2025) officially came into effect, superseding the previous standards for beer, fermented alcohol and distilled spirits industries. 

Compared with the former regulations, the new standard has expanded its scope and adjusted control items. Understanding which parameters must be monitored is essential for compliance.

The Eight Core Monitoring Parameters

Under GB 19821-2025, brewing facilities are required to monitor eight conventional pollutant indicators. The first is Chemical Oxygen Demand (COD), the core indicator of total organic load. Brewery wastewater contains high levels of organic matter from grain fermentation, distillation, and cleaning processes. Second is Biochemical Oxygen Demand (BOD₅), which measures the portion of organics biodegradable by microorganisms. 

Brewery effluent has good biodegradability, so COD and BOD₅ are usually tested together. Third is ammonia-nitrogen, which originates from protein decomposition in raw materials. Its concentration directly affects the stability of biological treatment systems and the safety of receiving waters.

Suspended solids (SS) come from raw ingredient washing, fermentation residues, and solid waste discharge. SS levels fluctuate significantly and serve as a key indicator of solid-liquid separation efficiency. pH value must be controlled within the specified range because acidic or alkaline wastewater from the brewing process can corrode pipelines and disrupt biological treatment units if left untreated. Total nitrogen is a newly added control item for certain beverage categories. Nitrogen in brewery effluent mainly comes from decomposed proteins and fermentation by-products. Excess total nitrogen increases the risk of eutrophication in receiving waters.

Total phosphorus is another critical driver of eutrophication, primarily sourced from grain ingredients and detergent discharges. It must be incorporated into routine monitoring programs. Lastly, color is a newly added control indicator for certain beverage categories. Improperly treated effluent may negatively affect the visual appearance of receiving waters.

Two Discharge Routes and Their Distinct Requirements

Brewery effluent can be discharged directly into natural water bodies or indirectly into centralized municipal or industrial wastewater treatment plants. Approximately 17 percent of wastewater is discharged directly, while the majority is discharged indirectly. For indirect discharge, because brewery wastewater has good biodegradability, the standard allows a flexible negotiated mechanism. 

Provided that there is no corrosion or clogging of sewer networks and that the receiving plant’s design capacity and treatment performance are assured, the discharging facility and the downstream plant may mutually agree on a concentration limit for specific pollutants. Such agreed limits, once approved and formally recorded in the pollutant discharge permit, become the enforceable indirect discharge limit for that parameter. 

For all non-negotiated parameters, the standard’s default indirect discharge limits still apply. This flexible arrangement reduces treatment costs for enterprises and promotes carbon reduction synergies.