Miller, Mark

Since 2006, Mark has served as Research Scientist for AquaShieldTM, Inc., a manufacturer of stormwater treatment systems headquartered in Chattanooga, Tennessee. He is responsible for product development, domestic and international regulatory affairs, and directs lab and field-testing programs. Mark is a member of the City of Chattanooga Stormwater Regulations Board. He holds an M.S. in Geology from Centenary College in Shreveport, Louisiana and a B.A. in Geology from the University of Tennessee, Knoxville.

Titles from this speaker

Evaluating Nitrogen Oxides Transformations at Low Dissolved Oxygen Concentrations

Abstract

This paper was presented at WEFTEC 2023 in Chicago, IL.

This study evaluates nitrogen oxides transformations at low-DO concentrations. Microbial community data coupled with biokinetics, and detailed process modeling facilitated an analysis of the fundamental mechanisms associated with SND and its interaction between biomass and intermediate nitrogen oxide species and readily biodegradable COD.

SpeakerJimenez, Jose

Presentation time

08:30:00

08:50:00

Session time

08:30:00

10:00:00

SessionLow Carbon BNR Fundamentals and Controls

Session locationRoom S502 - Level 5

TopicAdvanced Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Jimenez, Jose

Author(s)J. Jimenez 1; J. Boltz 2 ; M. Miller 3; K. Bauhs 5; B. Sturm 6; B. Rittmann 7; J. Jimenez 1;

Author affiliation(s)Brown and Caldwell 1; Woodard and Curran 2 ; Brown and Caldwell 3; Brown and Caldwell 5; University of Kansas 6; Arizona State University 7; Brown and Caldwell 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159062

Volume / Issue

Content sourceWEFTEC

Word count10

Description: Introducing a Series of New ASTM Standards Relating to Specifications and...

Introducing a Series of New ASTM Standards Relating to Specifications and Performance Protocols for Stormwater Control Measures

Abstract

ASTM Committee E64 on Stormwater Control Measures (SCMs) has published a series of new standards relating to specifications and performance protocols for manufactured water quality treatment devices (MTDs) including hydrodynamic separators (HDSs), media filters, and trash & debris capture technologies. These consensus-based ASTM standards have been developed to objectively measure the performance of these technologies to provide improved assurance on the efficacy of tested and verified technologies. This presentation will discuss the ASTM standards process and how it produces consistent quality procedures and products for the benefit of all stakeholders. An overview of these standards will be provided to gain insight into their rationale and essential elements. This presentation will also explore the potential benefits of using these standards as part of an SCM regulatory program; and what implementation of these standards within an authority having jurisdiction (AHJ) could look like. The prospect of a national validation process for ASTM standards via the Stormwater Testing and Evaluation of Products and Practices (STEPP) initiative will also be discussed. The overall intent of the ASTM standards process is to provide a high level of confidence to AHJs that the MTDs will provide long term and consistent treatment to meet water quality goals. Two E64 Subcommittees have been established to develop standards for both laboratory and field testing as E64.01 and E64.02, respectively. To date, laboratory standards include general specifications, standards applicable to HDSs, standards for media filtration, and a standard for trash & debris capture. General specifications address standard terminology for SCMs, silica-based test sediment and weighting factors for TSS removal on an annual basis. HDS standards and working items apply to TSS performance testing methods and data analysis, hydraulic characteristics and head loss, as well as scour testing to support online installations. Filtration standards and working items consider hydraulic characteristics, test sediment, performance testing and scour testing. The trash & debris capture standard is unique to laboratory protocols since it applies to manmade and natural materials >5 mm (5,000 microns) in two directions and uses a 'cafeteria style' approach for six testing elements. A standard for microplastics testing is also in progress. The first field-testing working standard addresses the use of autosamplers for the collection of paired influent and effluent flow-weighted composite samples. The development of new laboratory and field specifications and protocols is an ongoing effort with updates to existing standards occurring as the stormwater industry continues to advance MTD technologies and testing methodologies.

This paper was presented at the WEF Collection Systems and Stormwater Conference, April 9-12, 2024.

SpeakerMiller, Mark

Presentation time

14:30:00

15:00:00

Session time

13:30:00

15:00:00

SessionCollaborative Initiatives

Session number05

Session locationConnecticut Convention Center, Hartford, Connecticut

TopicConstruction, Funding, Green Infrastructure, Laboratory Methods And Analysis, Program Management, Public Utility, Rates, Stormwater Control Measure, TMDLs, Water Quality, Watershed Management

Author(s)

Miller, Mark

Author(s)M. Miller1

Author affiliation(s)AquaShield, Inc. 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Apr 2024

DOI10.2175/193864718825159336

Volume / Issue

Content sourceCollection Systems and Stormwater Conference

Word count18

More Than Just Energy Savings: Understanding the Benefits of Low DO Operation

Abstract

Introduction
Although advanced aeration controllers based on either ammonia (ABAC) or the ratio of ammonia to nitrate/nitrite (AvN) are becoming more common in WRRFs, the biological mechanisms of low DO operation are still not well documented. Low DO is generally referred to as operating below 0.5 mg/L but more specifically at a DO concentration that results in conditions that promote simultaneous nitrification and denitrification or SND, which can vary based on loading rates, process configuration, temperature, and floc morphology. Operating at low DO and achieving SND provides the opportunity for several process improvements in addition to achieving 10-30% aeration savings compared to conventional DO control. It can simplify operations and save additional energy by eliminating the need for multiple mixed liquor recycles and reduce supplemental carbon requirements. SND has also been shown to improve biological phosphorus removal. It is only when these mechanisms are understood can they be fully exploited to intensify treatment. This presentation will cover the current state of the industry as well as recent findings from an ongoing Water Research Foundation study (WRF 5083) investigating the benefits and mechanisms of low DO operation. The overarching research questions of this study that will be addressed are: 1. What setpoints represent low DO? 2. How are nitrification, denitrification, and phosphorus removal kinetics impacted by low DO operation? 3. What role does carbon cycling play in successful low DO BNR systems? 4. How do we maintain good settleability in low DO BNR systems?
Participating Facilities
The WRF study includes several participating facilities and pilot plants that are at different stages of planning, construction, or operation. The following facilities are either in operation or nearing the end of a demonstration phase. Rochester, MN: The Rochester WRF consists of a two-stage high purity oxygen plant and an activated sludge system operated in parallel. The activated sludge plant was operated in an A2O configuration and low DO operation was achieved by inputting low DO setpoints in the DO controllers and adjusting the DO setpoints as needed to prevent excessive ammonia bleed through. Hydrocyclone based wasting was also investigated to improve settling. City of Pueblo, CO: The James R. Dilorio WRF consists of a 19-MGD secondary facility using the Johannesburg BNR process. Aeration is controlled using a continuous AvN controller that results in an average low DO concentration of 0.2-0.5 mg/L. The facility has been achieving about 11 mg/L TIN and 0.6 mg/L TP with little chemical addition. Hydrocyclone based wasting is used at this facility to promote sludge densification. Operating at low DO has resulted in $150k/year in aeration savings and $300k/year in chemical savings. City of St. Petersburg, FL: The Southwest WRF is a 20-MGD A/O plant treating primary effluent. The plant operates at low DO concentrations and low SRT conditions to control nitrification and effluent N and P concentrations. Low DO operation has resulted to poor sludge settling affecting secondary clarifier capacity during the wet weather season. To improve the settling characteristics, hydrocyclone based wasting was recently implemented.
Results and Discussion
Using mixed liquor samples from the St. Petersburg facility, the specific denitrification rate was measured at different DO concentrations and the results are presented in Figure 1. As shown in this figure, denitrification was not measured until the DO concentration was less than 1 mg/L, but the rate was only approximately 20% of the maximum denitrification rate. It was not until the DO was lowered to 0.5 mg/L that the denitrification rate increased to about 70% of the maximum rate. Although denitrification at low DO was observed in the St. Petersburg batch tests and full-scale plant, at the Rochester WRF demonstration facility, SND was typically only observed in the first aerobic zone and not in the proceeding zones even though the DO was maintained at 0.3-0.4 mg/L as shown in profile in Figure 2. This was likely due to the type of substrate available after the first aerobic zone. An example of the impact of substrate type on denitrification is shown in Figure 3 where lower denitrification rates were measured after the readily biodegradable COD was consumed. These observations suggest that even lower DO concentrations are required in downstream zones that lack sufficient rbCOD and may rely on hydrolysis of slowly degradable COD. Testing at several facilities indicate that the maximum nitrification rates are not significantly reduced when adapted for low DO operation, but there is clear increase in the oxygen affinity. This results in higher nitrification rates at lower DO concentrations compared to conventional DO systems. The maximum nitrification rate is reduced by approximately 20-30% and apparent half saturation coefficient decreases to approximately 0.1 to 0.2 mg/L as shown in Figure 4 for the St. Petersburg facility. Overall, this only results in about 40% reduction of the nitrification rate at 0.2 mg/L DO. However, this rate can be increased by increasing the DO without losing a lot of overall nitrification capacity. Another observation in facilities operating at low DO concentrations is improved and more stable biological P removal. For example, the Rochester WRF had consistently lower OP concentrations as demonstrated in Figure 2. Lower nitrate in the RAS and more efficient use of influent carbon were obvious contributing factors, but higher P-uptake rates were also observed in low DO batch activity tests as shown in Figure 5. It is still unclear at this time what the mechanisms are, but it is hypothesized that low DO concentrations result in lower aerobic utilization rates of internally stored carbon that promotes higher P-uptake rates. These tests will be repeated at other facilities and the mechanisms investigated further in the pilot facilities. Poor settleability has often been associated with low DO operation, but these observations were from oxidation ditch plants that typically have poor settleability due to lack of proper selectors and plug flow conditions. As shown in Figure 6, if a process has well designed selectors that adequately reduce the influent rbCOD before the first low DO zone, the settleability remains good. Settling will be documented for the participating facilities.

Although advanced aeration controllers are becoming more common, the mechanisms of low DO operation are still not well documented. Operating at low DO provides the opportunity for several process improvements in addition to achieving 10-30% aeration savings. This paper elucidates the biological mechanisms of low DO operation based on observations at several WRRFs as part of an ongoing Water Research Foundation study (5083).

SpeakerMiller, Mark

Presentation time

13:35:00

13:50:00

Session time

13:30:00

15:00:00

TopicAdvanced Level, Energy Production, Conservation, and Management, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Miller, Mark

Author(s)Mark Miller1; Varun Srinivasan2; Ahmed Al-Omari3; Don Esping4; Pusker Regmi5; Kayla Bauhs6; Belinda Sturm7; Leon Downing8; Jose Jimenez9

Author affiliation(s)Brown and Caldwell, Charlotte, NC1; Brown and Caldwell, Boston, MA2; Brown and Caldwell, Alexandria, VA3; Brown and Caldwell, St. Paul, MN4; Brown and Caldwell, Beltsville, MD5; Brown and Caldwell, Nashville, TN6; University of Kansas, Lawrence, KS7; Black & Veatch, Madison, WI8; Brown and Caldwell, Maitland, FL9

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158603

Volume / Issue

Content sourceWEFTEC

Word count13

The Savings are in the Details: Fundamentals of ABAC Design

Abstract

The use of advanced aeration controls in WRRFs, particularly ammonia-based aeration control (ABAC), is becoming more widespread in North America. Compared to conventional dissolved oxygen (DO) control, ABAC utilizes all the available aeration tank capacity more efficiently by only nitrifying the influent ammonia necessary to obtain a desired effluent ammonia concentration. However, existing aeration systems are rarely capable of meeting equipment turndown requirements of ABAC since they were not originally designed to do so. This means that certain design parameters must be considered not only for existing systems but also for new facilities and aeration systems. The objective of this paper is to cover the fundamentals of designing around and implementing ABAC.

The following conference paper was presented at WEFTEC 2021, October 16-20, 2021. To read the full abstract, see "Abstract" tab below.

SpeakerMiller, Mark

Presentation time

16:00:00

16:15:00

Session time

16:00:00

17:30:00

SessionAmmonia-based Aeration Control: How to Make it Work

Session number313

TopicFacility Operations and Maintenance, Intelligent Water, Research and Innovation, Resilience, Disaster Planning and Recovery

Author(s)