Monitoring Parameters for Ceramic Wastewater Discharge

Wastewater monitoring in the ceramic industry is not a matter of running a single generic test. The parameters that matter depend on the specific process, the raw materials, and where the water goes. China’s GB 25464-2010 provides the core framework, but a sensible monitoring programme must distinguish between conventional pollution and ceramic-specific concerns.

The conventional parameters are the baseline. These include pH, suspended solids (SS), chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD₅), ammonia nitrogen, total nitrogen, total phosphorus, petroleum substances, sulfide, and fluoride. 

Suspended solids are especially prominent because clay, glaze residues, and polishing fines generate high particulate loads in washing, pressing, and glazing streams. COD and BOD₅, meanwhile, reflect the organic contribution from additives and cleaning operations, although levels are often lower than in many other industrial sectors.

What sets ceramic wastewater apart, however, is its heavy-metal profile. The characteristic pollutants are total lead, total chromium, total nickel, total cobalt, total copper, total zinc, and also total barium and total cadmium. These originate from raw minerals, frits, and glaze formulations. 

Glaze-containing wastewater, in particular, warrants attention at the workshop level rather than only at the final outfall, because lead and other metals can be present in a concentrated stream that should be intercepted before dilution. Adsorbable organic halides (AOX) also appear in the standard and are monitored at the workshop or production-facility discharge point.

Monitoring location matters as much as the parameter list. Conventional indicators such as pH, COD, ammonia nitrogen, SS, and total phosphorus are typically tracked at the enterprise wastewater total discharge outlet. Metals and AOX, by contrast, are linked to workshop or production-facility outlets, so that treatment performance can be judged before mixing with cleaner streams. For key outlets, flow, pH, COD, and ammonia nitrogen may require automatic monitoring, while other parameters follow periodic manual testing according to the facility’s status and discharge mode.