Treatment Process Meet Class 1A Standard

The Design Institutes' acceptance was based on recent results of a large-scale, pilot plant in the city of Tianjin. Siemens Water Technologies supplied the VertiCel process to Tianjin Capital Environmental Protection Co., Ltd. (TJCEP) for the retrofit of one of its five existing 90,000 cubic meters per day (CMD) wastewater treatment trains at the Xianyang Road Wastewater Treatment Plant. The full-scale pilot system demonstrated the process as a cost-effective solution for upgrade of existing wastewater treatment infrastructure to meet the new Class 1A standards, the most stringent wastewater discharge requirements for the country's regulatory agency.

In its existing design, the anoxic oxidation process at the Xianyang Road wastewater treatment plant was unable to meet the new Class 1A Total Nitrogen (TN) discharge standards of 15 mg/l. There were several critical requirements for the plant upgrade: timing was critical due to a tight construction schedule; space was limited, so existing infrastructure needed to be used; and normal plant performance was essential during the construction of the new plant. In view of these challenges, the technology upgrade needed to meet both the discharge standards and also be easily retrofitted into the existing plant.

The VertiCel biological nutrient removal system combines mechanical aeration in the anoxic tank with diffused aeration in the aerobic zones optimizing process efficiency. Since the aerated anoxic processes used in the VertiCel process nitrifies throughout the entire process, it can be easily retrofitted into the existing tanks. In addition, the VertiCel system design consumes on average 30% less power when compared to traditional aeration systems. The flexibility of the system design allowed the TJCEP to adopt the process to meet its specific needs, while meeting effluent standards.

The pilot demonstration was completed in June 2009. Siemens was awarded the contract to update the 450,000 CMD Xianyang Road Treatment Plant.