I read your informative blog regarding recommendations for jet cleaning leachate collection pipes. I have a question.
QUESTION: Say a landfill only has access to one end of a leachate pipe. This would be a situation where a new cell was built, where the uphill side of the cell butts up against an existing, pre-subtitle D cell with no leachate collection pipe. In other words, the uphill side of the new leachate pipe simply terminates rather than tie into an existing pipe.
To add to the issue, no vertical cleanout/riser pipe was installed on the uphill end (as this may impede waste operations in the area). There are of course riser and cleanout pipes and a sump on the downhill side for normal leachate collection. I would imagine that pumping water from the accessible side would push out any solids through the perforations into the leachate aggregate bedding, and may cause clogging there.
Is it possible, or reasonable, to flush this new leachate line?
ANSWER: There is always a possibility that a portion of dislodged material from the interior walls of the pipe will pass through pipe perforations and enter the gravel bedding around the pipe. However, due to the pipe slope, the great majority of the separated material flows down the pipe to the lowest point where it can be removed using a vac-truck.
Keep in mind also that, it’s true that leachate can partially flow through the bedding gravel toward the sump, but the role of the gravel is primarily protecting the pipe against compressive loads of waste above. Partial clogging of gravel around the pipe should not be considered as a malfunction of the system. Partial clogging of gravel normally may occur near the bottom portion of the gravel pack, which still allows leachate flow through gravel to pipe perforations above any clogged zone below.
In several instances, when a portion of a leachate collection pipe was opened up after being in service for a while, it did not support the idea of a clogged zone in the gravel pack. What was observed, included discolored gravel due to fine particles settling (from filtered leachate through geotextile) on gravel particles and a bit of the same particles near the bottom of the gravel pack.
I’ve never observed severe clogging of the gravel pack.
Thanks for your interest in the subject, and please stay in touch with any other questions. SCS freely shares best practices and advice within our industry; email us at
About the Author: Ali Khatami, PhD, PE, LEP, CGC, is a Project Director and a Vice President of SCS Engineers. He is also our National Expert for Landfill Design and Construction Quality Assurance. He has over 40 years of research and professional experience in mechanical, structural, and civil engineering.
A recent article in Waste Advantage Magazine features a detailed and comprehensive operation, the Sussex County, NJ Municipal Utilities Authority (SCMUA). The SCMUA team continuously looks for innovative solutions that will not only make operations more efficient but also help them to ‘be a good neighbor ’and resource to the surrounding communities.
“We are self-sufficient. Right now, we can manage our own solid waste through 2066, depending on a number of factors—recycling rates, population growth and what the regulations are going to be in 20 years, etc.,” says John Hatzelis, SCMUA Administrator.
The SCMUA is headed by a nine-person Board of Commissioners, and employs about 70 people, including wastewater, solid waste and central services staff, and receives support from SCS Engineers.
According to Tom Varro, Executive Director and Chief Engineer, “Everyone who works here knows their job and does it well. With the amount of traffic, 20,000 customers per month, 240,000 per year, that is a lot of potential for complaints. Every once in a while, you get someone that wasn’t happy, but for the most part, we get a lot of positive feedback, like ‘I love this place’, ‘I go here every Saturday’, ‘The guys are helpful’, etc. That is part of what we do as a service to the county and I think we’ve worked hard to get the staff trained and motivated.”
Learn more about this landfill operation’s best practices and outreach program in Waste Advantage.
Solar Ready CCR Site Closures Help Energy Companies Move Toward a Sustainable Future
Electricity is the one big energy source that can be free of carbon emissions. You can make it from the sun. You can make it from the wind. Tap the heat of the Earth, hydropower. While all utilities are moving in a sustainable, environmentally friendly direction, Aliant Energy stands out for making progress and keeping rates reasonable for consumers.
At the recent USWAG Workshop on Decommissioning, Repurposing & Expansion of Utility Assets held October 2019, Eric Nelson presented on the opportunities for solar generation at closed CCR sites and provided an overview of civil and geotechnical considerations when redeveloping closed sites as solar generating assets. His presentation demonstrated these considerations through the use of a case study.
SCS Engineers has assisted Alliant Energy with the design and/or construction of multiple coal combustion residual (CCR) surface impoundment closures. Two of the completed closures are the former Rock River Generating Station in Beloit, Wisconsin, and the M.L. Kapp Generating Station in Clinton, Iowa.
Both sites were closed by incorporating Alliant Energy’s vision to create “solar ready” sites. The Rock River site is now home to just over 2 megawatts (MW) of solar photovoltaic (PV) generating capacity, which was developed on the footprint of the now-closed on-site landfill and ash ponds. Although no solar assets have been developed at the site, the M.L. Kapp ash pond closure represents another opportunity for Alliant Energy to repurpose a closed ash pond for clean power.
Two additional closure designs are in process that incorporates similar elements, making them available for future solar generating asset development.
For more information visit SCS Engineers
Eric J. Nelson, PE, is a Vice President of SCS Engineers and one of our National Experts for Electric Utilities. He is an experienced engineer and hydrogeologist.
We recommend reading this article series to stay abreast of relevant knowledge from Bryan Staley, president and CEO of the Environmental Research & Education Foundation (EREF); Anne Germain, vice president of technical and regulatory affairs for the National Waste & Recycling Association (NWRA); Viraj deSilva, SCS Engineers wastewater treatment director; and testing results from New Hanover County whose capital investment in landfill infrastructure has proven to successfully treat effluent water to meet higher standards.
In September the City of Bangor will formally move over to a new arrangement in which residents will throw all of their recycling in with their trash and leave the mixed waste to be picked up from the curbside every week, as now happens with trash.
Bangor will also close their local recycling station as part of the city’s switch to a new integrated waste conversion plant in Hampden developed by Coastal Resources of Maine with Fiberight technology. The new facility includes a materials recovery facility (MRF), organic processing, plastics processing, anaerobic digestion (AD) and wastewater treatment. The integrated technology is intended to increase recycling rates without the need for extensive outreach programs and is easier for customers to use. According to Coastal Resources of Maine, the benefits are:
The advanced technologies are undergoing final testing at the Hampden, Maine facility, and are already in use at automated material recovery facilities in the United States and in Europe. The end product is cleaner and provides more diverse types of materials that can then be reused to create new products.
The Hampden facility’s advanced MRF has a high degree of separation, recovery, and monetization of commodity products, and then employs additional processes for generating clean cellulose, engineered fuels, and biogas from traditionally non-recyclable materials. Hired for the firm’s technical expertise and experience planning large municipal solid waste and biogas programs and facilities, SCS provided an in-depth examination and analysis of the technologies, program sustainability, and potential economic impacts of the facility.
The facility will serve 116 municipalities and public entities represented by the Municipal Review Committee, a non-profit organization that currently manages the waste disposal activities in Eastern and Northern Maine. The facility is planning to start accepting waste from its municipal customers shortly.
“With the planning and cooperation of many, Fiberight’s providing a truly sustainable solution in Maine while solving several challenges when consumers separate their recyclable materials and eliminating contamination,” stated Bob Gardner, SCS Engineers Senior VP. “The facility is capable of reusing nearly 150,000 tons of what formerly went into a landfill, is processing more municipal solid waste into high-value commodities, and is helping local municipalities and private waste haulers offset the cost of recycling.”
This EREF Summit will bring together practicing engineers, academics, industry professionals, government personnel and policymakers to facilitate discussion and provide various perspectives on the management, issues, and policies related to PFAS.
Per- and polyfluoroalkyl substances (PFAS) are a group of compounds that are man-made and are commonly used in industrial processes and consumer products such as food packaging, fire-fighting foams, metal plating, outdoor gear, popcorn bags, food wrappers, facial moisturizers, mattresses, carpeting, and cookware. Despite the widespread use of PFAS in everyday products, there are still significant knowledge gaps associated with the management of these compounds.
SCS Engineers is a sponsor of this EREF Summit. Liquids Management at SCS Engineers
Forester University recently hosted Dr. Viraj deSilva P.E., BCEE of SCS Engineers in their well-received educational webinar “All About PFAS: Emerging Contaminants That Are Everywhere.”
Dr. deSilva teaches you all you need to know to protect yourself and your community from PFAS—from generation, formation, and environmental release to sampling and analysis.
He provides an in-depth overview of the treatment of PFAS in sources that do not currently have maximum containment levels, such as landfill leachate, wastewater, surface water, and groundwater.
This course covers nomenclature, chemistry, sources, exposure, and future concerns as well as discusses the current regulatory status of these contaminants.
Learning Objectives
We encourage our readers to see the webinar on Forester University’s website. Credits: 1 PDH / 0.1 CEU. Forester offers registration savings to groups. Register here.
Additional Resources with Links – click to read
SCS Engineers’ Associate Professional, Lindsey Carlson recently coordinated a cleanup on the Beaver Dam River in Wisconsin. The cleanup is a part of the mission of Living Lands and Waters to clean the nation’s major rivers and watersheds. The Adopt A River Mile program enables people to support the mission in their own communities. SCS Engineers joined other members of the SWANA Badger Chapter, the Associated Recyclers of Wisconsin, and five members of the Beaver Dam community. SCS’s Adam Gorski and Phil Gearing are shown removing a tractor tire and other debris here.
Phil called the experience “a great time and very fulfilling.”
While getting wet and muddy, the team picked up trash and debris that filled one 5’x8’ utility trailer plus two pickup truck beds – that’s about 8 cubic yards for those not in the waste management industry 😉
The trash included a tractor tire; about seven car tires; an aluminum truck topper; an office chair; two bicycles (one still ridable); a motorcycle helmet; at least 15 feet of culvert piping; about 10 trash bags full of plastic bottles and other lightweight garbage; and quite a few other miscellaneous items.
Lindsey served as a volunteer on Living Lands and Waters’ barges during a week-long cleanup in Memphis in 2017, and “that’s how I came to know and become passionate about their cause,” she says.
Contact Living Lands and Waters to clean up your mile of river. Every mile makes a difference to help watershed conservation efforts in your community. Imagine the impact thousands of volunteers of all ages, willing to roll up their sleeves and get dirty are making. Thank you!
You’re not just an employee at SCS; you’re an Employee-Owner which means as you grow professionally, you develop yourself, exponentially. We value our team members, so we offer them more.
Have student debt? Join the SCS team, and we’ll make a monthly payment toward your eligible student loans up to $10,000.
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Our Employee Stock Ownership Program – ESOP provides stock ownership and retirement savings over and above our 401k program.
Instead of non-industry investors making a profit, we provide more to our employees for a job well done.
College is an excellent start to your professional career, but there’s so much more to learn. SCS offers professional and people skills development, mentoring from the best in the industry, and an environment of continual growth.
Already an experienced professional? Consider joining a firm that puts your expertise to work, creating the most innovative environmental solutions, and helping municipalities and businesses meet some of the most challenging issues of our time. SCS offers you opportunities to share your knowledge with industry peers, in publications, and with our client community.
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In addition to medical, dental, vision, Life, AD&D, LTD, STD, Accident & Hospital Indemnity, we personalize the employee experience with service achievement awards, blog and social media shout-outs, industry association networking, and community service opportunities.
Be more, do more, grow more.
Why settle for being employee #10234 when you can experience a deep sense of personal satisfaction where your achievements have a positive impact on our environment. SCS Engineers, one of the most respected environmental companies in North America, has open positions now.
EPA announced today a final policy to enhance effective partnerships with states in civil enforcement and compliance assurance work. The memorandum from EPA’s Assistant Administrator for Enforcement and Compliance Assurance Susan Bodine articulates the final policy procedures and practices for effective coordination between EPA and states when carrying out shared responsibilities under environmental laws.
The final policy memorandum is divided into three sections. The first section details requirements for joint planning and regular communication between EPA and states to promote enhanced, shared accountability. The second section of the policy provides greater detail on EPA and state roles and responsibilities in implementing authorized programs. The third and last section of the policy provides a process for the elevation and resolution of issues.
The issuance of today’s final policy replaces the interim guidance memorandum on enhanced planning and communication between EPA regional offices and states issued by Susan Bodine on January 22, 2018.
If you have questions about the final policy, please contact your SCS Project Manager, or send an email to .
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