Siemens technology for major wastewater treatment project in China
26 Mar 2012
First commercial application of Siemens’ IPS composting system’s biodrying process
Shenyang, China – Guodian Northeast Environmental Protection Industry Group, Ltd. has selected Siemens Industry Automation to supply an IPS composting system using a new ‘mechanically enhanced biodrying’ (MEB) process for the Shenyang wastewater treatment plant sludge treatment project in China.
According to Siemens, this will be the largest IPS composting facility ever built, and one of the largest sludge treatment processes in the world using non-thermal processing. The IPS composting system is scheduled to be commissioned in the fall of 2012.
The IPS system for Guodian in Shenyang will be used in a new sludge treatment facility that will serve three existing wastewater treatment plants and one new plant. The plants have been landfilling or land applying wet (20% solids) sludge. China recently passed a law that sludge must be a minimum of 60% solids for land application and/or landfill disposal.
In the first commercial application of Siemens’ IPS composting system’s biodrying process, the Shenyang plant is designed to dewater 1,000 wet tonnes per day of wastewater sludge, from 20% solids to 65% solids without the need to add heat, as in a thermal process.
The MEB process is also said to eliminate the need to add a significant amount of carbon-rich amendment or bulking agent that is typically the case with most other sludge composting processes.
For this application, the design basis is to use less than or equal to 2% (by weight) corn waste as amendment. An accelerated processing time of 22 days, maximum, is expected, even in this cold weather application.
Siemens conducted a six-month pilot test of the MEB process in the US - at an existing IPS composting system facility in Merrimack, New Hampshire from fall 2009 to winter 2010. This, it said, showed that the process could dry and stabilise wastewater sludge that has a total solids content of 20% and a volatile solids content of 60% without the need to add any soil amendments.
The MEB process provides a significantly lower energy usage alternative to traditional sludge dryers for reducing the mass of sludge sent to the landfill; thus, it is environmentally beneficial and also lowers operating costs. The study demonstrated that the operating cost savings over thermal drying was approximately 30%.
