Martin, Will, Martin

Martin, Will

Mr. Martin is an Associate in Hazen and Sawyer’s Twin Cities office. He has approximately 15 years of experience in design, operation, and construction of water and wastewater facilities and in compliance and regulatory reporting for industrial pretreatment facilities. Mr. Martin is experienced in the planning, design, and construction of wastewater treatment facilities. His experience includes hydraulic and process modeling, energy management, and design of improvements of wastewater treatment facilities. He is a member of Hazen’s CFD modeling group, and leads CFD modeling evaluations of primary and secondary clarifiers in the Midwest and across the US.

Titles from this speaker

Description: Combination of Metabolic, Kinetic and Physical Selection to Achieve Successful...

Combination of Metabolic, Kinetic and Physical Selection to Achieve Successful Full-Scale Continuous Flow Densification of Activated Sludge at Robert W. Hite Treatment Facility

Abstract

Abstract
â€“ In this work, we document successful densification of activated sludge at the Robert. W. Hite Treatment Facility utilizing continuous flow bioreactors and secondary clarifiers. Further, we discuss key factors that influence densification and nutrient removal performance.
#Introduction - The Metro Water Recovery (Metro) Robert W. Hite Treatment Facility (RWHTF) is a 220 million gallon per day (MGD) facility that currently achieves effluent total inorganic nitrogen (TIN) < 10 mg/L and total phosphorus (TP) < 1 mg/L. The RWHTF is faced with progressively tightening of effluent nutrient limits over the next 20 years. As part of facility planning, Metro proactively identified continuous flow densified activated sludge (DAS) as a technology that would help to address treatment requirements for the tightening nutrient standards. Metro commissioned a full-scale continuous flow DAS demonstration train in 2018 to: i) assess the feasibility of achieving densification, ii) inform treatment capacity rating and expected performance of full-scale DAS, and iii) gain insights into long term DAS operations. After several years of piloting with various operational configurations combined with physical selection the test train has demonstrated the ability to develop DAS. Once densified, SVI30 was maintained <115 mL/g (Figure 1), maximum solid loading rates capability increased from 30 to 60 (ppd/sf), and the RAS flow were reduced from 8.2 to 4 MGD providing additional secondary clarifier flexibility and eliminated the need for facility expansion. This work documents findings from the full-scale demonstration facility. Specifically, we will discuss: - Factors that have led to the development of DAS, - Insights from long term operation of DAS with physical selection. Although the pilot successfully densified, the impacts of densified solids across the entire facility must be considered before the technology is widely adapted. This study evaluates the impacts of densified sludge on various processes, including, thickening/rheology, E.coli removal, solid retention time, microbial community of AS, nutrient removal efficiency, and effluent suspended solids concentrations. A second paper will discuss how findings from the full-scale demonstration are being leveraged to maximize nutrient removal treatment capacity of the existing aeration basins (Abs) and secondary clarifiers (SCs) at RWHTF.
Methods
â€“ The full-scale DAS 'test' facility consisted of an isolated paired aeration basin (2.05 million gallons (MG)) and secondary clarifier (13,270 ft2) that was equipped with separate primary effluent pumping station designed to mimic full-scale diurnal flow patterns. The test facility was equipped with a hydrocyclone skid comprised of eight 10 m3/h hydrocyclones that was used for physical selective wasting. The test facility has been in operation since May 2018 and been used to test eight (8) distinct metabolic and kinetic selector configurations. Metro has also operated 'control' trains that do not have similar metabolic, kinetic and physical selection capabilities but represents current full-scale operation. Sampling and data collection of the test and control train occurred during densification start-up and continued into steady state operations.
Piloting, Sampling and Data Collection- Over the course of the demonstration operation, field sampling was performed at the facility to characterize performance as follows:
- Routine influent and effluent concentrations (COD, sCOD, NH4, PO4, TSS) within the test and control facilities,
- Profile sampling was performed across the test and control trains to characterize nutrients and organic carbon removal,
- Column settling tests and clarifier stress testing were performed to characterize performance under peak flow/load conditions
- DAS size distribution analyses was performed via particle size analyzer to determine how particle size changes over time in the MLSS, hydrocyclone overflow, hydrocyclone underflow, and secondary clarifier effluent.
- Microscopy analyses were performed to qualitatively characterize filaments and distribution of phosphorus and glycogen accumulating organisms
- Biomass activity testing was performed to identify changes to biomass function (e.g., nitrifier, phosphorus uptake)
- Weekly measurement of E. coli were taken. Grab samples were collected at both test and control secondary clarifier effluents. E.coli was quantified via the IDEXX method - Piloting of the centrifuge thickening system on densified stream. The system was operated with a variety of polymer doses and throughputs to evaluate effect on solids percentage and percent capture.
Results and Discussion
“ Key results from the demonstration are summarized below:
- The test train had significantly improved settling characteristics versus the control train (Figure 1). Observations suggested a 40% reduction in SVI30, and SVI5 for the test versus the control train. These results confirmed that the combination of metabolic, kinetic and physical selection employed in the test train allows for continuous flow densification.
- Size distribution analyses indicated that the test train MLSS frequently comprised larger particles that the control train (Figure 2). This can be partially attributed to the benefits of the hydrocyclones. Depending on the specific configuration tested and the degree of kinetic selection provided, the size distribution in the test train was also variable. In general, periods with more defined and stronger metabolic and kinetic selection resulted in the generation and retention of larger particles in the test train. Full discussion of these findings will be provided.
- Rheology testing confirmed that both DAS and CAS behaved as non-Newtonian fluids with pseudoplastic properties (Figure 3). Results suggested that there was limited different between DAS and CAS at MLSS concentrations less than 1%. DAS appeared to have a lower viscosity than CAS at solids concentrations between 1 and 2%. At 5% solids , DAS was observed to have a higher viscosity than CAS.
- Qualitative microscopic analyses indicated that both test and control trains had strong clusters of phosphorus accumulating organisms (PAOs; Figure 4). However, the test train was observed to have lower levels of filaments relative to the control train.
- Results also suggested that the test train had lower secondary effluent E. coli concentrations relative to the control train (Figure 5). Cumulatively, these results indicate combining metabolic, kinetic and physical selection could allow for stable densification in continuous flow applications at the RWHTF. The full scale plant evaluation indicates that densification continues to be a viable option to increase secondary clarifier capacity while delivering enhanced E. coli removal and minimal negative secondary impacts such as increased secondary clarifier effluent TSS. The test train operation is currently ongoing to verify performance through seasonal changes. An additional mixing evaluation is also currently being conducted to determine minimal mixing requirements to ensure even suspension of the densified AS in anaerobic and anoxic zones. The presentation and paper will contain updated data from all sampling performed.

In this work, we document findings from Metro Water Recovery (Metro) efforts to achieve densified activated sludge at the Robert. W. Hite Treatment Facility (RWHTF). Discussion of factors that were observed to influence densification is provided.

SpeakerMartin, Will

Presentation time

15:35:00

15:50:00

Session time

15:30:00

17:00:00

TopicFundamental Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Martin, Will

Author(s)Rudy Maltos1; Will Martin2; Alyssa Mayer3; Daniel Freedman4</sup, Wendell Khunjar5; Blair Wisdom6; Liam Cavanaugh7; Isaac Avila8; Ron Latimer9; Paul Pitt10; Alonso Griborio11

Author affiliation(s)Metro Water Recovery, Denver, CO1; Hazen and Sawyer, Minneapolis, MN2; Hazen and Sawyer, Cincinnati, OH3; Metro Water Recovery, Denver, CO4; Hazen and Sawyer, Fairfax, VA5; Metro Water Recovery, Denver, CO6; Metro Water Recovery, Denver, CO7; Black and Veatch, Blacksburg, VA8; Hazen and Sawyer, Atlanta, GA9; Hazen and Sawyer, San Francisco, CA10; Hazen and Sawyer, Hollywood, FL11

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158694

Volume / Issue

Content sourceWEFTEC

Word count24

Densification Specific Considerations for Secondary Clarifier Assessments

Abstract

Intensification is a major innovation for water resource recovery facilities (WRRFs) to realize cost-effective use and deployment of infrastructure. One of the promising technologies and approaches for process intensification is densified activated sludge (DAS). Secondary clarifiers are a key unit process to ensure retention of the solids inventory and permit compliance. The performance of clarifiers depends on several interrelated processes and factors including hydrodynamics, settling, turbulence, flocculation, sludge rheology, atmospheric conditions, tank geometry, internal features and loading conditions. Several tools and design “rules of thumb” are available from regulatory loading guidelines such as Ten State Standards, sludge specific assessment tools such as state point analysis, and calibrated, site-specific tools such as 2D and 3D computational fluid dynamics (CFD) modeling. These tools have been in use for decades with traditional sludge settling characteristics. However, the industry is still working through methods and procedures to assess the impacts of DAS settling characteristics on traditional secondary clarifier operations and loading guidelines. This paper will highlight the use of clarifier evaluation tools for DAS applications, including key considerations, observed performance, potential loading rates, and other relevant properties. Case studies are highlighted to demonstrate potential impacts at full-scale WRRF sites.

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

SpeakerMartin, Will

Presentation time

11:30:00

12:00:00

Session time

10:30:00

12:00:00

SessionSecondary Clarification Advancements

Session locationRoom S401d - Level 4

TopicAdvanced Level, Municipal Wastewater Treatment Design

Author(s)

Martin, William

Author(s)W. Martin 1; A. Griborio 2 ; R. Latimer 3; R. Vandermeulen 4; G. Ram Mohan 5; W. Martin 1;

Author affiliation(s)Hazen and Sawyer, St. Paul, MN 1; Hazen and Sawyer, Hollywood, FL 2 ; Hazen and Sawyer, Atlanta, GA 3; Hazen and Sawyer 4; Hazen and Sawyer 5; Hazen and Sawyer 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159196

Volume / Issue

Content sourceWEFTEC

Word count8