Tuesday 1:00 PM

Room: Sapphire

Maximizing Wet Weather Flows in Biological Ammonia Oxidation and Nutrient Removal Facilities

Through a combination of state-of-the-art technologies, the boundaries of reliable wet weather treatment have been defined for facilities conducting ammonia oxidation and/or nutrient removal. This presentation will synthesize case studies where innovative technologies ranging from biologically active ballasted sedimentation to activated sludge inventory management and secondary clarifier optimization were used to allow an increase in wet weather flow treatment capacity. However, on the upper bound, we have identified the maximum flow that the state-of-the-art can treat, and thus the point where regulatory relief must be pursued. Thus the presentation will conclude with a methodology for developing the dataset neccesary to approach regulatory agencies to seek relief from short term permit requirements (daily and weekly) to offset protracted high flow/low temperature conditions.

Moderator:  Krishna Pagilla


Dimitri Katehis, PhD, PE - Greeley and Hansen

Having worked side by side with plant operators for more than 10 years Dr. Katehis has successfully deployed innovative technologies in the US, the Middle East and Australia. A specialist in whole plant integration, he has developed wet weather solutions for nutrient management facilities for plants ranging from 30 to greater than 300 mgd.  He is experienced in helping utilities navigate the deployment of new unit processes through technology transfer, training and upstream process.  A recognized industry expert in nutrient removal, Dr. Katehis is the author of new Sidestream Nutrient Treatment chapters in both the WEF/ASCE (Water Environment Federation/American Society of Civil Engineers) Manual of Practice No. 8 as well as WEF’s Nutrient Removal Manual of Practice 34. He has developed advanced  bioaugmentation and nitritation/anammox (deammonification) process configurations for plants in New York City, Philadelphia, and Washington DC among others. His work has been published in US and European journals and multiple conference proceedings.


Dave Hobbs, PE - Greeley and Hansen

Mr. Hobbs has over 38 years of engineering experience in water and wastewater design and construction. He is currently an Associate at Greeley and Hansen, a leading environmental consulting engineering firm dedicated to the water and wastewater industry. 

Mr. Hobbs has served as project manager for a wide variety of storm water, water, and wastewater engineering planning and design projects for public and private utilities and agencies. In addition to these activities, he was one of the authors of the "Water and Wastewater Treatment Plant Hydraulics” chapter in the Hydraulic Design Handbook.

Mr. Hobbs received a bachelor’s degree in Civil Engineering from the University of Illinois, and is a registered professional engineer in Illinois, Indiana, Oklahoma and Indiana.

S. Archana Kuchimanchi -Greeley and Hansen

Ms. Sai Archana Kuchimanchi has more than 5 years of engineering experience in wastewater design engineering and is a registered professional engineer. She is currently an engineer at Greeley and Hansen, a leading environmental consulting engineering firm dedicated to the water and wastewater industry. Ms. Kuchimanchi has a Masters in Environmental Engineering from Illinois Institute of Technology, Chicago and a Bachelors in Civil Engineering from India.

Prior to joining Greeley and Hansen in 2007, Ms. Kuchimanchi spent a year doing internships with the Illinois EPA and American Resource Solutions. As an IEPA intern, she performed hydraulic and environmental evaluations to study the performance of the existing wastewater treatment systems for a meat processing facility. During her internship with American Resource Solutions, she was overlooking the demolition at the OHare Modernization project, in collaboration with Tetra Tech.

She has been a member the Illinois Water Environment Federation since 2004 and has been actively involved in numerous Young Professional activities.  She is also currently the Chair of the IWEA Young Professional Committee.