Drouhard, Bernadette

Bernadette Drouhard is a Water Process Specialist, EIT with Brown and Caldwell based in Atlanta, GA.

Titles from this speaker

Evaluating Phosphorus Recovery from Biosolids to Address Eutrophication in Florida

Abstract

The land application of biosolids has provided nutrients and organics to agricultural land for decades. More than half of the solids generated in the United States during water reclamation are stabilized and beneficially used as soil amendment. The use of biosolids reduces dependence on inorganic fertilizer, increases the organic content of the soil, provides a low-cost and locally produced fertilizer to the agricultural community, reduces greenhouse gas emissions and sequesters carbon. Historically, biosolids application rates have been calculated almost exclusively on the nitrogen (N) content in the biosolids and the manner in which the biosolids were managed, surface applied, or incorporated into the soil. Basing application rate on nitrogen alone can result in applying phosphorus (P) beyond the crop's agronomic requirements. Like all fertilizers without an adequate buffer to surface water and depth to groundwater, a portion of the phosphorus applied may enter the ground or surface water. In an effort to limit the over-application of phosphorus, a number of states, including Florida, are requiring the development of nutrient management plans. These plans require the determination of the agronomic phosphorus application rate along with the one for nitrogen. The plan is for the application rate to be controlled by the more stringent of the two. Some states require soil monitoring and calculating the total cumulative amount of P that can be applied based on the Cationic Exchange Capacity of the soil. Recent regulations in some States have begun to use the percent Water Extractable Phosphorus (WEP) in estimating the agronomic rate for phosphorus application. Some States use the monitored data. The State of Florida uses multiple methods of calculating the agronomic P application rate depending on the percent WEP, above or below 14.5% WEP. The St. Johns River Water Management District, supported by the State of Florida Department of Environmental Protection (FDEP), has initiated a project titled 'Resource Enhancement and Recovery of Domestic Wastewater Residuals'. The objective of this project is to identify and evaluate technologies to recover the phosphorus (P) in biosolids, reducing the amount in the beneficially used material. The project includes: 1. Evaluate existing technologies and assess regional needs. 2. Review empirical data from technology vendors to quantify expected P-recovery performance. 3. Compare feasible technologies based on cost, performance, and capacity. This project was conducted in three separate tasks. This presentation describes the overall project with a focus on the modeling and technology comparison tasks, which were Tasks B and C. Task B included the identification, screening and evaluation of proven and promising P-recovery technologies that may recover P and reduce the content in biosolids. Twenty P-recovery technologies were screened using criteria established by the project team and the District. Following the screening of the preliminary technologies, a total of four were selected for further evaluation. The task also reviewed the impact the composting and thermal drying have on phosphorus availability. Task C included the modeling of four P-recovery technologies at two Water Reclamation Facilities (WRF) in the State. Both facilities use biological nutrient removal processes for their liquid stream treatment. One WRF anaerobically digests the solids generated during treatment. The second uses aerobic holding, which provides a degree of aerobic stabilization. Each of the selected P-recovery technologies was modeled under both treatment and stabilization scenarios. The model output allowed the project team to estimate the comparative phosphorus recovery rates. Another objective of Task C was to understand the opportunities and challenges associated with implementing a P-recovery technology. This included a cost estimate to implement P-recovery at a set capacity and the impact the technologies could have on the phosphorus concentration in the facilities' biosolids. The evaluation also used non-monetary criteria to identify the technologies that can support a wide range of WRRFs throughout Florida. The project included the development of an educational document to inform policymakers and regulators in the State of Florida regarding the benefits of biosolids and the technologies available to support that use, including P-recovery technologies. This presentation provides a summary of the work performed as part of the project and the recommended steps in support of beneficial use of biosolids in the State of Florida.

This paper was presented at the WEF Residuals and Biosolids Conference, June 18-21, 2024.

SpeakerGuzman, Sarah

Presentation time

16:15:00

16:45:00

Session time

13:30:00

16:45:00

SessionResource Recovery and Sustainable Practices

Session number06

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicLand Application, Regulatory Requirements, Technology Comparison

Author(s)

Guzman, Sarah

Author(s)S. Guzman1, B. Drouhard1, M. Lang 1

Author affiliation(s)Black & Veatch 1; Black & Veatch 1; Black & Veatch 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159428

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count11

Life After Landfills: A Statewide View of Changing Biosolids Management in Georgia

Abstract

Introduction and Background Historically in Georgia, a large proportion of biosolids produced in the state has been disposed of in landfills. This proportion has grown over the last several decades because of the implementation of regulatory changes such as the sanitary sewage sludge incineration rules and landfilling costs have remained relatively flat compared to disposal and beneficial use alternatives. In recent years, landfill disposal of biosolids in Georgia has become much more challenging with landfills either significantly increasing tipping fees or not accepting biosolids. These challenges have been driven by increased regulatory focus on landfill disposal of biosolids following several slope failures that occurred in Georgia, including one at a major landfill in the metro Atlanta region in 2018. The Georgia Environmental Protection Division (EPD) has approved additional legislation (via changes to Georgia's Solid Waste Management Rule 391-3-4) that requires any landfill accepting more than 5 percent high moisture content waste (HMCW) to have a HMCW management plan in place to document mitigation measures for receiving this material. HMCW is classified as anything with a moisture content of greater than 40 percent by weight (i.e., less than 60 percent dry solids). Typical biosolids dewatering installations generate a product with a dry solids content between 15 percent and 25 percent, which is classified as HMCW. While facing challenges with respect to landfill disposal, there are also potential opportunities to make use of biosolids as a resource. Biosolids contain valuable nutrients and organics, presenting potential opportunities for beneficial use as fertilizers, soil amendments, or for energy recovery. Project Details and Outcomes Acknowledging biosolids challenges faced by Georgia wastewater utilities, the Georgia Environmental Finance Authority (GEFA) commissioned Black & Veatch to perform a study to evaluate the challenges and opportunities related to biosolids management in the state and provide recommendations regarding strategies and funding for biosolids management going forward. A summary of the study scope and objectives is provided in Table 1. This presentation will highlight the key project outcomes and opportunities to aid utilities in the State as they pivot towards diversifying biosolids management practices. Key project outcomes that will be presented are listed below. - Results of a statewide survey that captured 80% of the estimated wastewater flow in 2019 and informed the National Biosolids Data Project for Georgia. Survey respondents provided information regarding the costs of biosolids management and end use, interest in partnering with other organizations for regional solutions, and feedback regarding funding mechanisms. See Figures 1 and 2 for more detail. - A gap analysis of current and future biosolids production estimates compared to available landfill capacity to accept high moisture content waste and available outlets for beneficial reuse, e.g., agricultural land area suitable for biosolids land application. See Figure 3. - Opportunities and recommendations to assist utilities with alternative biosolids management strategies. This includes co-processing with municipal solid waste, modifications to GEFA funding initiatives and application criteria, and regional management strategies to capitalize on economies of scale. See Figure 4 listing opportunities and barriers to regionalization. The study produced a regionalization roadmap to guide utilities through potential avenues to regional solutions. Conclusion Although this study is specific to the State of Georgia, utilities across the U.S. may benefit from this presentation and subsequent conversations about biosolids management challenges like increased landfill and tipping fees, organics co-processing, or land application bans due to PFAS concerns. GEFA hopes to build upon the study's findings through programs and projects that are awarded funding soon. The 2022 Call for Projects opened on September 1, 2021.

This paper was presented at the WEF Residuals and Biosolids Conference in Columbus, Ohio, May 24-27, 2022.

SpeakerDrouhard, Bernadette

Presentation time

14:30:00

15:00:00

Session time

13:30:00

16:45:00

Session number13

Session locationGreater Columbus Convention Center, Columbus, Ohio

TopicBeneficial use, Landfill, Regionalization

Author(s)

B. Drouhard

Author(s)B. Drouhard1; A. Carroll2; G. Knight3; S. Simpson4; L. Moss5

Author affiliation(s)Residuals and Biosolids Speaker; 1Residuals and Biosolids Speaker; 2Residuals and Biosolids Speaker; 3Black & Veatch Corporation (HQ); 4Residuals and Biosolids Speaker; 5

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2022

DOI10.2175/193864718825158435

Volume / Issue

Content sourceResiduals and Biosolids

Word count13