Physical/Chemical Treatment

Treating Inorganic Liquid Wastes Chemically and Safely

The Physical/Chemical Treatment Plant (PCT) treats inorganic liquid waste such as acid, alkaline, chromate and cyanide. Generally, waste is detoxified through chemical processes like neutralisation, oxidation and reduction.

The recommended packaging for liquid inorganic waste is plastic drums with bunghole, pallet tanks or plastic pails.

Like other waste types arriving at the Waste Management Centre, samples are taken from all containers in each consignment and sent to the laboratory for analysis. Upon receiving the confirmation treatment results, the respective loads of waste are brought to the assigned treatment plant.

At the PCT Plant, the initial preparation to treat the consignment begins with the unloading of the waste into one of the five unloading stations. The five unloading stations segregate PCT waste into five categories:-

• Chromate waste
• Acid waste
• Miscellaneous waste
• Alkaline waste
• Cyanide waste

At the unloading station, the waste is pumped into an intermediate storage tank with a capacity of 4 m3 and in larger consignments; waste is further channelled into a 50-m3 tank. From the storage tank, the waste will be transferred into one of the two reactors at the PCT Plant where the actual treatment will take place.

Physical Treatment

The resulting residue from the various processes in the form of slurry is either used as a water source at the Solidification Plant or filtered in the filter press. The filter cake is further treated at the Solidification Plant before finally being disposed off in the Secured Landfill

Types of PCT Waste

Typical waste and their DOE code numbers treated at the PCT plant are:-