Siemens Energy has received a contract from Indonesia to deliver a Zimpro wet air oxidation system. The technology will be part of the new Gundih gas processing plant where it will treat wastewater contaminated during the gas production process. The contract was awarded by a consortium consisting of PT Inti Karya Persada Tehnik and PT Adhi Karya (Persero) Tbk. As general contractors, both companies are working together to build the gas processing plant for the end customer, the state-owned Indonesian oil and gas PT Pertamina EP.

The Gundih gas processing plant is under construction in Blora in Indonesia's Central Java province. The facility will have a daily gas production capacity of 50 million standard cubic feet (1.4 million standard cubic meters) after start-up at the end of 2013. Siemens' Zimpro wet air oxidation system will treat a mixture of alkaline wastewater and wastewater generated during sulfur recovery by destroying odorous and high COD (chemical oxygen demand) pollutants and generating an effluent that meets the Indonesian environmental regulations for discharge.

Wet oxidation is the oxidation of soluble or suspended components in an aqueous environment using oxygen as the oxidizing agent. When air is used as the source of oxygen, the process is referred to as wet air oxidation (WAO). The system will oxidize odorous reduced sulfur species such as sulfides and mercaptides, and will also break down complex organic contaminants, such as phenols, to either carbon dioxide and water, or biodegradable organics.