Hilts, Brian

Mr. Hilts is an environmental engineer at CDM Smith with 25 years of experience in the water reclamation industry. In the last 15 years, he has focused his efforts on disinfection technologies, both mature and innovative, such as chlorination/dechlorination, UV disinfection, peracetic acid (PAA) and performic acid (PFA) in an effort to help utilities find the best solution to meet their financial, operational, maintenance, and regulatory needs. Mr. Hilts serves as CDM Smith's Water Reclamation Disinfection Discipline Leader, is the Chair of the WEF Disinfection and Public Health Community and is the Principal Investigator for WRF project 5274, Evaluating the Full-Scale Impacts of DAS on Disinfection Efficacy.

Titles from this speaker

Evaluating Full-Scale Impacts of Activated Sludge Densification on Disinfection Efficacy: A WRF Tailored Collaboration

Abstract

Background Water resource recovery facilities (WRRFs) around the world are constantly faced with significant challenges 1, 2. It is estimated that WRRFs are operating at an average of 81% of their design capacity, while 15% of systems are at or have exceeded that threshold3. As the most prevalent biological nutrient removal (BNR) process, any improvements to conventional activated sludge (CAS) processes are highly desirable in our industry4. However, upgrading CAS trains is costly and alternative technologies often tend to be more energy-intensive, expensive1, and time consuming to install, commission, and operate. Thus, the use of physical selectors (e.g., hydrocyclones) for biomass densification has emerged as a front-runner for increasing secondary clarifier capacity and improving nutrient removal. Objective and Approach Despite the many studies exploring the advantages of densified activated sludge (DAS) systems compared to CAS systems, DAS impacts on microbial communities and fecal indicator bacteria (FIB) are unknown2, 5. In 2023, the Water Research Foundation funded a tailored collaboration with the Metro Water Recovery (MWR) in Denver. The collaboration aimed to investigate FIB removal and disinfection kinetics. This study focused on CAS and DAS treatment trains at three North American full-scale operating WRRFs (Figure 1). The WRF project aims to: A) Compare E. coli concentrations over a 15-month period and investigate factors influencing differences (e.g., granulation size distribution, floc/granule mass fraction, floc/granule aSRT, microscopy, COD, Turbidity, TSS, NH3, pH, Temperature, Color, UV-254, TKN, TP, TOC). B) Determine how changes in Secondary Effluent (SE) properties between DAS and CAS affect disinfection efficacy using chlorine, peracetic acid (PAA), performic acid (PFA) and ultraviolet disinfection (UV) seasonally (n=12), with the same water quality parameters listed in Objective A. C) Assess impacts of operational variables on DAS and provide utilities with recommendations. These can include how to utilize modeling and statistics to improve performance using demand and decay values and mechanistic disinfection efficacy models D) Determine if additional analyses (e.g., protozoa counts, granule sieving analyses) provide operational value to utilities adopting DAS. Results Data collected for one year at the MWR Hite Treatment Facility highlights the statistically significant difference in E. coli concentrations between the CAS and the DAS trains (Figure 2). This could be explained by a variety of variables that have not yet been evaluated. FIB counts may be impacted by the predator protozoan community5, but this has yet to be supported by data (Figure 3). While percent mass fraction (Figure 4) and seasonality (Figure 5) have been hypothesized to impact DAS E. coli counts6, this has not been shown by the preliminary data collected, which highlights the importance of a more detailed study to explain the differences observed . Summary DAS is able to be implemented with low capital cost while increasing the capacity of CAS systems. However, there is little data on how SE from DAS systems impact downstream disinfection processes. This WRF project will evaluate the impact DAS systems have on disinfection processes compared to CAS systems. Data collection and testing for this project will begin in April 2024.

Densification has emerged as a cost-effective means to increase the capacity of conventional activated sludge (CAS) processes at WRRFs. While many studies have explored the advantages of densified activated sludge (DAS) systems, its impacts on disinfection are unknown. This project will compare the E. coli concentrations between full-scale CAS and DAS systems; will compare disinfectants by performing disinfection dose response testing; and will develop efficacy models based upon the results.

SpeakerHilts, Brian

Presentation time

14:30:00

15:00:00

Session time

13:30:00

15:00:00

SessionEvaluating Plantwide Impacts of AGS and DAS

Session number606

Session locationRoom 343

TopicIntermediate Level, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Hilts, Brian, Goldman, Josh, Maltos, Rudy, Maal-Bared, Rasha, Kaymak, Baris

Author(s)B.A. Hilts1, J. Goldman2, R. Maltos3, R. Maal-Bared4, B. Kaymak5

Author affiliation(s)1CDM Smith, UT, 2Metro Wastewater Recovery, 3Metro Water Recovery, 4CDM Smith, 5CDM Smith

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159717

Volume / Issue

Content sourceWEFTEC

Word count15

Description: Less is More: Using an Integrated CT Approach to Optimize the Chlorination System...

Less is More: Using an Integrated CT Approach to Optimize the Chlorination System for Miami-Dade

Abstract

In the face of aging infrastructure, tight capital improvement budgets, and more stringent regulatory requirements to protect public health and the environment, many utilities across the country continually try to do more with less. Utilities are looking for ways to optimize their treatment processes, including disinfection, to stretch limited funds available to address these competing demands. According to the disinfection survey conducted by the WEF Disinfection and Public Health committee in 2017, 58% of respondents disinfect with chlorine. One method to optimize chlorination processes, and possibly defer, reduce, or eliminate capital improvements and reduce operations cost, is to utilize an ICT approach to control chlorine addition. Miami-Dade WASD completed a bench-scale study at their SDWWTP in an effort to determine whether additional chlorine solution storage tanks were required. They found that by optimizing the chlorine dose, they can delay constructing additional storage tank capacity, and reduce annual O&M costs.

In the face of aging infrastructure, tight budgets, and more stringent regulatory requirements, many utilities across the country are looking for ways to optimize their treatment processes, including disinfection. One method to optimize chlorination processes, and possibly defer, reduce, or eliminate capital improvements and reduce operations cost, is to utilize an ICT based approach to control chlorine addition. Miami-Dade WASD completed a bench-scale study at their SDWWTP to determine whether additional chlorine solution storage tanks were required. They found that by optimizing the chlorine dose, they can delay constructing additional storage tank capacity, and reduce annual O&M costs.

SpeakerHilts, Brian

Presentation time

11:25:00

11:40:00

Session time

11:00:00

12:00:00

SessionAdvanced Controls for Disinfection and Potable Reuse

Session number211

TopicAdvanced Level, Disinfection and Public Health, Facility Operations and Maintenance, Intelligent Water, Water Reuse and Reclamation

Author(s)

Brian Hilts