Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

Session Overview
Session 17B: Leadership, Social Equity and Workforce Development: Workforce Development
Tuesday, 10/Sep/2019:
3:00pm - 4:30pm

Session Chair: Katie Dillon, HDR;
Location: F150

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3:00pm - 3:45pm

How do you Transfer 40 years of Outfall Design and Construction Expertise?

Kristen Jackson, Vince Rybel

Jacobs, United States of America; ,

Treated effluent from wastewater treatment plants (WWTP) is discharged into rivers, estuaries, and marine waters. Fortunately, outfall designs have improved since the early days of open pipes discharging from the shoreline. Today’s designs include buried outfall pipelines with diffusers, multiple risers and duckbill check valve ports in order to improve mixing, avoid impacts to the river water quality, and comply with water quality standards under all flow scenarios. Design considerations for outfall construction projects includes challenging in-water work windows, tight permit requirements during construction, working from a barge on underwater construction, and diver-friendly design details.

This presentation features a senior engineer with over 40 years’ experience in outfall design and construction and a young professional with a keen interest in learning from the best. This presentation will share how to work as a team to transfer experience and expertise from one generation to the next and feature two case studies of recently completed river outfall projects - one at Clackamas County Water Environment Services’ Kellogg Creek WRRF and one at the City of Wilsonville’s WWTP.

The Kellogg Creek WRRF Outfall Improvement included 167’ of 48” buried outfall pipeline and a 120’ diffuser with 7 ports, and was constructed during the in-water work window summer 2016. This improved outfall substantially improves dilutions to support elimination of ammonia limits in the NPDES permit. The outfall improvements design incorporated projected future effluent flows and chemical concentrations to enable the Kellogg Creek WRRF to comply with all Oregon water quality standards for decades.

The City of Wilsonville Outfall Replacement included 285’ of 42” buried outfall pipeline and a 60’ diffuser with 5 ports on vertical risers. The project originated with discovery in 2014 that the existing single port outfall was broken and leaking at the shoreline. A temporary outfall pipe was installed to repair the broken line until design and construction of a new multiport diffuser and outfall was completed in the summer of 2018. The replacement outfall design incorporated projected effluent flows and chemical concentrations to enable the Wilsonville WWTP to comply with all Oregon water quality standards for decades.

3:45pm - 4:30pm

STEPS to Improve Phosphorus Removal at the West Boise Water Renewal Facility

Allison Hornak1, Joshua Baker2

1HDR, United States of America; 2City of Boise, United States of America; ,

The City of Boise operates the West Boise Water Renewal Facility (WBWRF) which utilizes an enhanced biological phosphorus removal (EBPR) for phosphorus removal. In 2017, the City developed a Secondary Treatment Enhancement Project (STEP) intended to improve phosphorus removal at WBWRF. The WBWRF has the added challenge of dewatering biosolids from the Lander Street Water Renewal Facility and struvite harvesting of phosphorus. Side stream phosphorus sources provide challenges to the EBPR process. The City reviewed biological and chemical alternatives to augment their existing EBPR process and reduce effluent phosphorus and developed three viable alternatives to be implemented under the STEP program.

1. Installation of baffle walls in the South Plant aeration basin to reduce short-circuiting.

2. Chemical coagulant addition at select process locations to reduce phosphorus entering the EBPR system.

3. Heating of primary sludge fermenters to yield higher volatile acids to the EBPR system.

The City installed the baffle walls in December 2018 and plans to begin construction of chemical phosphorus removal facilities in August 2019. The fermenter heating improvements have been evaluated but postponed until the chemical phosphorus removal improvements have been completed and are operational.

Preliminary results show reduced effluent phosphorus which may be attributed in part to the new baffle walls. Operational data and the process for evaluating STEP project alternatives will be reviewed. The audience will gain an understanding of potential alternatives for enhancing an existing EBPR process as a result of attending the presentation.

Of note, the project was developed by a combination of young and senior staff from both the City and the City’s consultant. Some take-a-ways will be presented regarding Bridging of the Gap and knowledge transfer from senior to young staff.

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