Yilma, Eyasu

Eyasu Yilma is a registered professional engineer in Washington, DC, and a graduate of the University of Leuphana L&uuml;neburg in Germany....

Joined:

About Yilma, Eyasu

Eyasu Yilma is a registered professional engineer in Washington, DC, and a graduate of the University of Leuphana L&uuml;neburg in Germany. Eyasu has more than 20 years of experience in water and wastewater management, worked as a consultant for German consulting firms, DC Water, and the World Bank. He has authored several documents, including the Multi-Jurisdictional Use Facilities Cost Share and the Potomac Interceptor Renewal Procedure for DC Water, and the Cost-Effective Design Procedure for the World Bank. Eyasu is currently working for DC Water as the manager of the Potomac Interceptor Sewer Network, which conveys flow from Washington suburban jurisdictions to the Blue Plains Advanced Wastewater Treatment Plant.

Yilma, Eyasu

Titles from this speaker

Air Dispersion Model as part of Odor Mitigation Optimization: DC Water - Potomac Interceptor

Abstract

The Potomac Interceptor (PI) is one of the longest sewer systems that conveys flow from the Washington DC suburbs to the Blue Plains Advanced Wastewater Treatment Plant. It conveys approximately 20% of inflow to Blue Plains with an average flow of 55 mgd and peak flow of 150 mgd. This interceptor system starts from Dulles International Airport and flows cross-country until it nears the Potomac River. From there, it runs nearly parallel to the Potomac River and enters the Maryland/District boundary. The main trunk of the Potomac Interceptor is approximately 50-miles long. The Potomac Interceptor Service Area is so large that flow can take up to four days to reach Blue Plains. This long travel and time of sewage retention in the sewer system causes a strong rotten egg smell generated by H2S. It also causes a rotten cabbage smell generated by DMS, a Protein produced inside the sewer system. DC Water has built six odor control facilities-two in Virginia, two in Maryland, and one in DC-designed to remove foul air from the sewer system by passing it through activated carbon and permanganate reactors, releasing nearly odorless air to the atmosphere. These facilities are effective in removing air and creating negative pressure in the entire sewer system greatly reducing foul air releases in neighborhoods. However, the treated air dispersion at the odor control facilities is not ideally designed to direct air through their exhausts in a direction away from adjacent neighborhoods, parking lots, and restaurants. DC Water has developed several options to optimize air dispersion at the odor control facilities and further reduce the impact of odor in PI service areas. One of the options is to model the air movement and, based on the result, to determine the exhaust velocity by adjusting the diameter of the exhaust pipes at the odor control facilities. Another outcome would be to re-orient the exhaust angle in conjunction with the air dispersion model results to minimize impacts to adjacent neighborhoods. Air Dispersion Model DC Water performed an odor dispersion modeling analysis to determine odor impacts from the six odor control facilities along the PI to the surrounding communities. This analysis uses the EPA's latest standard for atmospheric dispersion modeling, AERMOD (v. 18081). Model Selection The AERMOD model (v. 18081) was used with options as recommended in the EPA's Guideline on Air Quality Models (EPA, 2005). The following supporting preprocessing programs for AERMOD were used:

* BPIP-Prime (v. 04274)

* AERMAP (v. 18081) This model is recommended for short-range (< 50 km) dispersion from the source. The model incorporates the Plume Rise Model Enhancement (PRIME) algorithm for modeling building downwash. AERMOD was run with the following options:

* Regulatory default options

* RURAL dispersion option

DC Water performed an odor dispersion modeling analysis to determine odor impacts from the odor control facilities along the Potomac Interceptor to the surrounding communities. The Odor modeling data were analyzed to determine the frequency of odor events above the target value at ambient receptors. The finding confirms the importance of timely media replacement and a program for anticipating breakthrough.

SpeakerYilma, Eyasu

Presentation time

09:00:00

09:20:00

Session time

08:30:00

10:00:00

SessionIntercepting Odors and Corrosion: Modeling, Mitigation, and Monitoring

Session number304

Session locationRoom 244

TopicAir Quality and Odor Management, Collection Systems, Facility Operations and Maintenance, Intermediate Level, Public Communication and Outreach

Author(s)

Yilma, Eyasu, Ward, Matthew, St Louis, Kenrick

Author(s)E. Yilma1, M. Ward2, K. St Louis3

Author affiliation(s)1DC Water, DC, 2The WATS Guys, Inc., NC, 3DC Water & Sewer Authority, DC

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159563

Volume / Issue

Content sourceWEFTEC

Word count15

Description: Potomac Interceptor Long-term Corrosion Prevention Program: DC Water Using...

Potomac Interceptor Long-term Corrosion Prevention Program: DC Water Using Innovative Tools to Support Strategy Development

Abstract

DC Water’s Potomac Interceptor system has suffered from corrosion for many years. According to recent CCTV inspection, approximately 95% of the Potomac Interceptor has shown signs of corrosion. Inputting field data to sewer process models that integrate ventilation resulted in recommendations focusing on the operation of existing forced ventilation odor control systems to support reduction in corrosion. These recommendations have been adopted in the PI operation protocol. In addition, DC Water developed a long-term corrosion prevention program implementing various corrosion mitigation measures identified in the case study.

This manuscript presents a case study of DC Water's Potomac Interceptor (PI) Corrosion Control Strategy using sewer process models with newly integrated ventilation modelling. These models were used to determine the best operational strategy to prevent odor emissions, reduce corrosion, and improve management of the existing forced ventilation facilities. In addition, DC Water developed a corrosion prevention program to implement various corrosion mitigation measures identified in the case study

SpeakerYilma, Eyasu

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionManaging the Third Effluent Part II

Session locationRoom S501d - Level 5

TopicCollection Systems, Facility Operations and Maintenance, Intermediate Level, Municipal Wastewater Treatment Design

Author(s)

Yilma, Eyasu

Author(s)E. Yilma 1; A. Satyadev 2 ; A. Romero 3; M. Ward 3; E. Yilma 1;

Author affiliation(s)DC Water 1; DC Water, Washington, DC 2 ; Jacobs 3; The WATS Guys 3; DC Water 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159223

Volume / Issue

Content sourceWEFTEC

Word count16

Remote Smart Monitors Bolster Sewer Odor Mitigation Program for District of Columbia Water and Sewer Authority

Abstract

INTRODUCTION: MAKING WATER & AIR A PRIORITY WITH SMART TECHNOLOGY DC Water distributes drinking water and collects and treats wastewater for more than 700,000 residents and 21.3 million annual visitors in the District of Columbia. DC Water also provides wholesale wastewater treatment services for 1.6 million people in Montgomery and Prince George's counties in Maryland, and Fairfax and Loudoun counties in Virginia. To collect wastewater, DC Water operates 1,900 miles of sanitary and combined sewers, 16 stormwater stations, 22 flow-metering stations, nine (9) wastewater pumping stations, and 75,000 catch basins and manholes. To treat wastewater, DC Water operates the Blue Plains Advanced Wastewater Treatment Plant, which is considered the largest advanced wastewater treatment facility in the world. On average, nearly 300 million gallons of raw sewage flows into the plant daily. THE CHALLENGE: A 'CATCH 22' LEADS TO A SMART DECISION The Potomac Interceptor (PI) is a 50-mile-long linear gravity sewer system that flows parallel to the Potomac River from Montgomery County, Loudoun County and Fairfax County to the District of Columbia (DC). Due to many drops in the system, high turbulence is created, causing massive corrosion. To prevent corrosion at high rates, forced ventilation of the headspace is needed, but that releases odorous sewer gas into the atmosphere. Six (6) odor control facilities (OCF) were constructed to provide long-term control of odors and to reduce Hydrogen Sulfide and Dimethyl Sulfide gasses that cause corrosion and odors. After construction of the OCF's, DC Water continued to focus on controlling the odor and corrosion in the system by implementing a multi-phase OCF Optimization Plan. Phase 1 of the Optimization successfully reduced odor complaints, however, DC Water still looked for a way to measure the gas release in smaller concentrations to help control odor across the 50 mile; preserve utility resources; and better manage utility personnel time. THE SOLUTION: H2S GAS MONITORING WITH SMART TECHNOLOGY Taking a more proactive approach, DC Water started a pilot odor control optimization program in 2022, which included smart technology to measure real-time H2S gas levels. The sensors gave DC Water constant visibility of the odorous gasses in the system and alerted them of a potential H2S spike near the OCFs. The sensors seamlessly operate with the hardware system, enabling reliable, real-time measurements of H2S levels in remote locations over extended periods of time by utilizing the iridium satellite network. A total of six (6) sensors were installed along the linear Potomac Interceptor at critical points. THE RESULT: MEASURABLE RETURN ON SMART INVESTMENT In addition to a better overall understanding of the PI, DC Water has been able to quickly identify and address problematic areas and be notified in real-time of a potential H2S spike. By setting high-level alarms, DC Water is notified of a potential change in operation at the OCF. The real-time data has allowed the utility to better allocate resources (staff and vehicle travel costs). The real-time data recorded from the sensors showed odor complaints decreased to 0. Along with eliminating odor complaints, DC Water increased efficiency of its operation. The utility was able to reduce inspection and travel time for crews, and it reduced overtime and fuel costs by having increased awareness of the sewer system to pinpoint issues across the 50-mile-long Potomac Interceptor before they occur. Additionally, DC Water has been able to prolong the use of its infrastructure by decreasing corrosion. DC Water continues to demonstrate how technology is preserving money, staff time and assets. The utility has garnered a positive return on its investment.

The District of Columbia Water and Sewer Authority (DC Water) uses smart sewer technology to monitor and reduce Hydrogen Sulfide (H2S) gas in its 50-mile-long Potomac Interceptor (PI). The H2S gas causes corrosion in the concrete sewer pipe and when the gas is released for ventilation, the odor provokes complaints from residents and business owners along the PI corridor, between the Washington Dulles International Airport and the nation's capital.

SpeakerSatyadev, Abhiram

Presentation time

09:30:00

09:50:00

Session time

08:30:00

10:00:00

SessionIntercepting Odors and Corrosion: Modeling, Mitigation, and Monitoring

Session number304

Session locationRoom 244

TopicAir Quality and Odor Management, Collection Systems, Facility Operations and Maintenance, Intermediate Level, Public Communication and Outreach

Author(s)

Yilma, Eyasu, Brenner, Phil, Satyadev, Abhiram

Author(s)E. Yilma1, P. Brenner2, A. Satyadev3

Author affiliation(s)1DC Water, DC, 2SmartCover, PA, 3DC Water & Sewer Authority, MD

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159737

Volume / Issue

Content sourceWEFTEC

Word count17

Base text size -

Yilma, Eyasu

About Yilma, Eyasu

My Recent Activity