Industry requests for a versatile biosolids end-product that could be produced using less energy fueled Siemens Water Technologies to conduct a pilot study focusing on Mechanically Enhanced Biodrying (MEB) as a new application of the existing Siemens IPS composting technology.
The study illustrated how the IPS system serves a dual purpose by biodrying materials for fertilizer or fuel while using minimal energy expenditure, compared to conventional drying methods. It was determined that an automated, agitated bin composting technology could achieve 65 percent solids concentration (35 percent moisture) in biosolids by using only the finished dried product as the amendment.
In the pilot study, the IPS Composting System was found to consistently dry to 65 percent solids with an in-feed mixture of at least 40 percent solids, comprised of dewatered cake (of at least 20 percent solids) and recycled dried product discharged from the IPS system (of at least 60 percent). Overall, the solids concentration increased an average of approximately one percent per day and as much as two percent per day in the agitated bin system when minimum in-feed conditions were met. Summer and winter studies focused on such variables as ambient air temperature, feedstock properties, turning frequency, bin retention time, and process aeration cycles.
The MEB process uses the biosolids’ own biological characteristics to heat the material and, in doing so, to evaporate some of the moisture. Aeration and agitation from the IPS equipment further enhance the biological process drying. The IPS biodrying process is more cost effective and energy efficient than thermal drying, and the resultant end-product can be used as fertilizer or feedstock for incineration. Creating a biosolids fuel product with an energy-conservative process makes MEB an ideal companion for conversion technologies. It was also found that applying similar MEB principles to biosolids composting addresses the challenge confronting plants when wood waste and other carbon-rich amendments are in short supply. Further research is looking at also possibly using the process before gasification.
In the pilot study, the IPS Composting System was found to consistently dry to 65 percent solids with an in-feed mixture of at least 40 percent solids, comprised of dewatered cake (of at least 20 percent solids) and recycled dried product discharged from the IPS system (of at least 60 percent). Overall, the solids concentration increased an average of approximately one percent per day and as much as two percent per day in the agitated bin system when minimum in-feed conditions were met. Summer and winter studies focused on such variables as ambient air temperature, feedstock properties, turning frequency, bin retention time, and process aeration cycles.
The MEB process uses the biosolids’ own biological characteristics to heat the material and, in doing so, to evaporate some of the moisture. Aeration and agitation from the IPS equipment further enhance the biological process drying. The IPS biodrying process is more cost effective and energy efficient than thermal drying, and the resultant end-product can be used as fertilizer or feedstock for incineration. Creating a biosolids fuel product with an energy-conservative process makes MEB an ideal companion for conversion technologies. It was also found that applying similar MEB principles to biosolids composting addresses the challenge confronting plants when wood waste and other carbon-rich amendments are in short supply. Further research is looking at also possibly using the process before gasification.
Besides municipal WWTPs, the IPS system is also applicable to other industries: the UK Department of Environment, Food and Rural Affairs (DEFRA) recently approved the IPS system, to be considered a "closed reactor" under Regulation (EC) 1774/2002 to compost catering wastes. The United Kingdom has composting guidelines that are more stringent than most of the other EU countries because of concerns over swine vesicular disease, foot-and-mouth disease, and other animal-related infections.
Contact USA:
Ms. Karole Colangelo
Corporate Public Relations Manager
Siemens Water Technologies Corp.
Hoffman Estates, IL
847-713-8458 phone
E-mail address karole.colangelo@siemens.com
Contact USA:
Ms. Karole Colangelo
Corporate Public Relations Manager
Siemens Water Technologies Corp.
Hoffman Estates, IL
847-713-8458 phone
E-mail address karole.colangelo@siemens.com
