https://www.americancityandcounty.com/wp-content/themes/acc_child/assets/images/logo/footer-logo.png
  • Home
  • Co-op Solutions
  • Hybrid Work
  • Commentaries
  • News
  • In-Depth
  • Multimedia
    • Back
    • Podcast
  • Resources & Events
    • Back
    • Resources
    • Webinars
    • White Papers
    • IWCE 2022
    • How to Contribute
    • Municipal Cost Index – Archive
    • Equipment Watch Page
    • American City & County Awards
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Privacy Statement
    • Terms of Service
American City and County
  • NEWSLETTER
  • Home
  • Co-op Solutions
  • Hybrid Work
  • Commentaries
  • News
  • In-Depth
  • Multimedia
    • Back
    • Podcasts
  • Resources/Events
    • Back
    • Webinars
    • White Papers/eBooks
    • IWCE 2022
    • How to Contribute
    • American City & County Awards
    • Municipal Cost Index
    • Equipment Watch Page
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Cookie Policy
    • Privacy Stament
    • Terms of Service
  • newsletter
  • Administration
  • Economy & Finance
  • Procurement
  • Public Safety
  • Public Works & Utilities
  • Smart Cities & Technology
  • Magazine
acc.com


Sludge baggers work for small treatment plant

Sludge baggers work for small treatment plant

Not many wastewater plants have to deal with too little sludge. But, when attempting to justify the purchase of sludge dewatering equipment, the Granville
  • Written by Craig, Larry E.
  • 1st July 1995

Not many wastewater plants have to deal with too little sludge. But, when attempting to justify the purchase of sludge dewatering equipment, the Granville Township Wastewater Treatment Plant (WWTP), Pa., faced exactly that problem.

The WWTP treated an average of 130,000 gpd in 1992, using two se-quencing batch re-actors, two aerobic di-gesters and chlorine disinfection with discharge to the Juniata River. All of the sludge from the di-gesters was dewatered using drying beds.

Looking for an alternative to the labor-intensive beds, the Granville plant began to evaluate dewatering technologies, such as filter presses, centri-fuges, vacuum filters and thermal techniques. But even the smallest version of each of these conventional equipment alternatives was maintenance and energy intensive for a small plant and provided unneeded excess capacity.

After evaluating an alternative, Granville Township realized its answer was in the bag — literally. A sludge bagger system was the low-flow solution to the dewatering dilemma.

“The township procured the equipment by direct bid,” says plant Chief Operator Tim Tressler. “Plant personnel then erected a block building on the existing drying bed and installed everything themselves. The entire project, including the bagger, cost less than $50,000.”

The sludge bagger system is cost-effective because gravity does all the dewatering work. An influent slurry pump and a polymer feed system are the only energy-consuming components required.

After conditioning, the sludge is introduced into a gravity drainage plenum with an open top for easy cleaning and maintenance. The slurry is then continuously dewatered without mechanical shaking or auxiliary pressurization while it works its way into one of the bag chambers. As the bags begin to fill, water penetrates through the woven material and collects for return to the head of the plant. One worker can then remove full bags from the unit using a fork dolly.

The bags of dewatered sludge, typically 10 to 15 percent dry solids at this point, may then be disposed of or stacked on pallets for further dewatering. When the bags are stacked in an outdoor location, natural evaporation from within the bags may increase the solids content to as much as 40 to 60 percent.

The bags represent the largest single operating cost. The non-woven polypropylene bags originally selected for the Granville plant cost nearly $3 each. Assuming 60 bags are processed each week, that translates into an annual operating cost of $9,360. To reduce this cost, GTMA personnel switched to woven polypropylene bags that have the same capacity but cost about 50 percent less.

Ultimately, Granville landfills the bagged sludge. By allowing evaporation to reduce the weight of each bag to about 25 pounds, the GTMA is able to dispose of 80 bags per ton. This equates to 9,300 gallons of the original digester liquid sludge.

Bagger systems are available in 3-, 6- and 12-bag combinations, and each bag has a volume of approximately 22 gallons. Each operating cycle roughly consists of a 2-hour fill period, followed by two hours to four hours for additional drainage. The resulting processing capability is about 20 pounds of dry solids per bag per cycle.

Sludge bagger units are shop-wired and skid-mounted for easy installation. Operation is less labor intensive than drying beds, and bags are reusable in some cases.

Tags:

Most Recent


  • Bloomberg
    Three U.S. cities to adopt Bloomberg Philanthropies Mayors Challenge-winning project to combat climate change
    Bloomberg Philanthropies has announced that seven global cities, including three in the United States, will be adopting Stockholm’s Biochar Project, which turns plant waste from parks and homes into a charcoal-like substance that residents can use in their yards to help combat climate change. The project was the winner of the 2014 Bloomberg Philanthropies European […]
  • 10 cities ideal for hybrid or full-time telecommuters seeking an outdoor lifestyle
    When the pandemic was first realized, cities emptied out, highways were suddenly devoid of cars and storefronts shuttered overnight. The assumption in many communities was that it would last for a few months and then everything would return to normal—those who’d left would return to their office jobs and apartments.  But these two years later, […]
  • Sludge baggers work for small treatment plant
    Take American City & County's budgeting survey
    With the recently passed infrastructure-related legislation by the federal government, local administrators across the United States are poised to make historic investments into their communities.  Given the generational precedence of this action, we’re curious about the state of local budgets—what expense lines are increasing the fastest year-over-year? In what area has federal funding been the […]
  • Atlanta, Ga.
    Six cities and counties will take stock of underutilized assets in Rethinking Revenue incubator
    The Government Finance Officers Association in collaboration with various organizations including Urban3 and the Sorenson Impact Center has been spearheading a forward-looking approach to public financing, the Rethinking Revenue Project, an investigation of the foundational structure of government revenue and underutilized assets, for about a year now. A new initiative launched by the collaboration is […]

Leave a comment Cancel reply

-or-

Log in with your American City and County account

Alternatively, post a comment by completing the form below:

Your email address will not be published. Required fields are marked *

Related Content

  • NLC releases State of Cities 2021 report
  • How governments can keep employees safe as they return to work
  • Lessons from your friendly neighborhood public service employees
  • North Texas alliance partners with Marketplace.city on smart government solutions

White papers


How to Assemble a Rockstar Website Redesign Steering Committee

7th June 2022

Hand Hygiene: Compliance Matters

23rd May 2022

What it Takes to Build a Winning Esports Program

23rd May 2022
view all

Events


PODCAST


Young Leaders Episode 4 – Cyril Jefferson – City Councilman, High Point, North Carolina

13th October 2020

Young Leaders Episode 3 – Shannon Hardin – City Council President, Columbus, Ohio

27th July 2020

Young Leaders Episode 2 – Christian Williams – Development Services Planner, Goodyear, Ariz.

1st July 2020
view all

Twitter


AmerCityCounty

Three U.S. cities to adopt Bloomberg Philanthropies Mayors Challenge-winning project to combat climate change dlvr.it/ST4bjk

29th June 2022
AmerCityCounty

10 cities ideal for hybrid or full-time telecommuters seeking an outdoor lifestyle dlvr.it/ST4T5g

29th June 2022
AmerCityCounty

Take American City & County’s budgeting survey dlvr.it/ST0qQP

28th June 2022
AmerCityCounty

Six cities and counties will take stock of underutilized assets in Rethinking Revenue incubator dlvr.it/ST0ZVp

28th June 2022
AmerCityCounty

Seamless Cooperative Experience Saves Indiana City Exponentially in Time and Money dlvr.it/SSxp95

27th June 2022
AmerCityCounty

10 best large cities for fishing dlvr.it/SSxbSZ

27th June 2022
AmerCityCounty

Generational differences present an opportunity to reinvent public sector service delivery dlvr.it/SSxbN7

27th June 2022
AmerCityCounty

Report: Local and state governments are facing a retention crisis; the worst could be yet to come dlvr.it/SSnmS7

24th June 2022

Newsletters

Sign up for American City & County’s newsletters to receive regular news and information updates about local governments.

Resale Insights Dashboard

The Resale Insights Dashboard provides model-level data for the entire used equipment market to help you save time and money.

Municipal Cost Index

Updated monthly since 1978, our exclusive Municipal Cost Index shows the effects of inflation on the cost of providing municipal services

Media Kit and Advertising

Want to reach our digital audience? Learn more here.

DISCOVER MORE FROM INFORMA TECH

  • IWCE’s Urgent Communications
  • IWCE Expo

WORKING WITH US

  • About Us
  • Contact Us

FOLLOW American City and County ON SOCIAL

  • Privacy
  • CCPA: “Do Not Sell My Data”
  • Cookies Policy
  • Terms
Copyright © 2022 Informa PLC. Informa PLC is registered in England and Wales with company number 8860726 whose registered and Head office is 5 Howick Place, London, SW1P 1WG.
This website uses cookies, including third party ones, to allow for analysis of how people use our website in order to improve your experience and our services. By continuing to use our website, you agree to the use of such cookies. Click here for more information on our Cookie Policy and Privacy Policy.
X