University of Massachusetts Amherst

Search Google Appliance


Park Awarded U.S. Patent for Method to Reduce Sludge Generation in Wastewater Treatment Plants

Chul Park

Chul Park

Dr. Chul Park, an Associate Professor in the Department of Civil and Environmental Engineering at the University of Massachusetts Amherst, and his former Ph.D. student Dr. Dong-Hyun Chon were recently awarded a U.S. Patent on their pioneering technology to decrease the production of sludge, the byproduct produced from wastewater treatment. See patent information »

“This invention uses a very small anaerobic reactor inserted into the side-stream of the conventional wastewater treatment systems,” says Park. “With this configuration, my team has demonstrated that we can decrease the production of sludge up to 70 percent, compared to conventional systems, and produce useful bioenergy methane from small anaerobic reactors.”

As the patent abstract explains: “The systems and methods described provide for reducing sludge generation, and thus sludge wasting and handling, by including an anaerobic completely stirred tank reactor (CSTR) as a bioreactor in a side-stream. The CSTR provides a significant simplification of side-stream treatment design, enhanced sludge minimization, and enhanced removal of nitrogen and phosphorous without the need to add organic carbon. The described systems and methods provide generation of biogas from the activated sludge system.”

Currently, wastewater treatment plants (WWTP) in the U.S., including those in the local areas near UMass Amherst, spend more than 50 percent of their operational budget to handle the sludge. While sludge itself is energetic material and presents the source of organic matter and nutrients for WWTPs, it is a nuisance material that must be removed on a daily basis.

As Professor Park says, “Currently, the treatment plants thicken and haul out the sludge, which will then be incinerated or landfilled. These ways of removing sludge are, thus, very costly and continue to face substantial regulatory and societal challenges due to their impacts on the environment.”

Dr. Park’s anaerobic side-stream reactor (ASSR) process can potentially turn today’s challenge on sludge and wastewater treatment into an opportunity. The ASSR-based wastewater treatment substantially reduces the production of sludge, while producing methane from small anaerobic digesters. The invention is developed based on Park’s research finding that sludge is actually much more degradable than previously thought but requires certain conditions for that degradation to happen.

Park is currently working with local WWTPs and municipalities in the Commonwealth of Massachusetts to apply the ASSR technology for full-scale wastewater treatment. He is also working with a private company in Mexico to disseminate this technology in Central and South American countries. Since operation of WWTPs is governed by environmental regulations, Park believes that successful demonstration of the ASSR process in full-scale settings is a crucial step for industrializing the technology. Park believes that collaboration with municipalities and private entities will enhance his efforts to industrialize the ASSR process for worldwide use.

Park, who has been at UMass Amherst since 2007, is very active and interested in transferring the technology to the industrial use. He has been awarded multiple research grants and honors that recognize his efforts to develop the technology that can potentially solve the current environmental problems. As examples showing his efforts at technology transfer, his recent research projects on oxygenic photo-granules for aeration-free wastewater treatment are supported by: NSF Grant Opportunities for Academic Liaison with Industry (with co-PIs Dr. Caitlyn Butler and Dr. Chris Wilson); Manning Proof of Concept Funds (UMass); and a MassCEC Catalyst Program Award. (April 2017)