Powdered Activated Carbon Treatment (PACT)

Powdered activated carbon treatment is a widely accepted wastewater treatment technology. In this treatment the powdered activated carbon is added to an aerobic or anaerobic treatment system. The physical adsorption property of the powdered activated carbon facilitates the removal of dangerous waste products. The carbon is used as a buffer against the consequences of toxic organics in the wastewater. Carbon is added to the wastewater after the primary clarification at a dosage rate based on the degree of treatment required. A small amount of liquid cationic polyelectrolytes is added before the final clarification to improve effluent clarity. In such systems, carbon adsorbtion and biological treatment are mixed into a single synergistic treatment step. This system provides major cost reduction when compared to granular carbon treatment and activated sludge options.


The powdered activated carbon has the adsorptive nature that helps it to remove many complex and high molecular weight organics that are hard to biodegrade in conventional activated sludge process. There are many organic toxins included in these compounds, priority pollutants, surfactants, and soluble dyes. The PACT process has been applied at various municipal treatment facilities and at many industrial plants that receive significant industrial loads.

Powdered activated carbon treatment is an innovative biological remediation process using activated sludge in association with powdered activated carbon. The compounds adsorbed to the activated carbon are usually recycled with the sludge so they have enough system retention time. Thus it allow a higher degree of biological degradation.

Features of PACT

• These systems use powdered activated carbon and coconut shell activated carbons, which provide optimum operation.
• The aerobic and anaerobic biological systems performance is improved by stabilizing them against upsets and shock loading.
• They are able to control color and odor.
• These systems provide less costs for disposing of residuals.
• They have no problem with pre-filtration or column plugging.

Benefits of PACT

• It helps in the removal of non-biodegradable organics.
• It reduces the emission of organic compounds to the environment specially during the period of acclimation.
• It provides better settling of the biomass or powdered activated carbon sludge.
• It offers protection of the microbial population from toxic shocks.
• The powdered activated carbon helps in reducing effluent concentrations of organics during the acclimation period.