CETP for Electroplating & Metal Finishing Clusters

Electroplating and metal finishing clusters concentrate hundreds of small enterprises operating chrome, nickel, copper, zinc, and cyanide gold/silver plating operations in shared industrial estates. Each unit generates small volumes of highly hazardous effluent — cyanide, hexavalent chromium, heavy metals, and acid/alkali rinse waters — that require specialist treatment beyond the financial and technical capability of individual MSMEs. CPCB mandates Common Effluent Treatment Plants for these clusters, with the CETP providing centralised heavy metal removal, biological treatment, and where directed, Zero Liquid Discharge — while individual units are responsible for upstream cyanide destruction and Cr⁶⁺ reduction before discharge to the common network. Learn more about our CETP and electroplating wastewater treatment capabilities.

The treatment sequence in an electroplating CETP begins after unit-level pre-treatment at each member unit (cyanide destruction by alkaline chlorination, Cr⁶⁺ reduction by sodium metabisulphite). The combined pre-treated effluent arrives at the CETP inlet with residual heavy metals — Total Cr 5–50 mg/L, Ni 5–30 mg/L, Cu 5–50 mg/L — that the CETP removes by alkaline precipitation at controlled pH 9–10.5, using lime or NaOH, followed by coagulation, flocculation, and inclined plate clarifier to settle the metal hydroxide sludge. The clarified effluent then proceeds to biological treatment for COD and BOD reduction, followed by sand filtration and discharge. For ZLD-mandated clusters, RO + MEE provides the final concentration and evaporation stage. See our heavy metal precipitation wastewater treatment page for detailed process information.

Spans Envirotech designs electroplating CETPs as integrated systems — unit-level pre-treatment protocols, CETP-level heavy metal precipitation, biological treatment, sludge management (hazardous waste classification, press filtration, TSDF dispatch), and ZLD where required. Our designs include member unit monitoring systems for cyanide and Cr⁶⁺ at the CETP inlet — essential to verify that units are complying with mandatory pre-treatment before discharge to the common network, and to protect the CETP's biological stage from cyanide or Cr⁶⁺ breakthrough.