Turning Manure into megawatts (Swine Farm Biogas Renewable Energy Project)

As I noted in my last post, Withers & Ravenel’s Swine Farm Biogas Renewable Energy Project, located in Bladensboro, North Carolina, is one of this year’s ACEC Excellence in Engineering Award winners.

I asked the folks at Withers & Ravenel to give share more about their project, how it was conceived, and how it was designed.

Why Swine Farms? What was the genesis of this Project?pig outline

North Carolina is “pork proud”, with approximately 9 million hogs on farms scattered throughout the eastern part of the State. These farms rely on open pit lagoons and land application for the treatment and disposal of animal waste.   However, open-air treatment lagoons have a poor reputation among some lawmakers, residents and environmentalists. They are accused of creating sickening odors, allowing methane to escape into the atmosphere, and contaminating groundwater and streams.

Because of environmental concerns, the State temporarily suspended permitting the construction and operation on any new swine farms utilizing lagoon treatment systems in 1997, and required new farms to meet “environmentally superior technology” (EST) standards.  Since the enactment of the suspension, there have been no new hog farms introduced in North Carolina.

Tax Credits, Legislation, and Funding

In 2007, the State passed Senate Bill 3, which pushes the use and development of renewable energy standards, the State took a big step toward encouraging innovative treatment technologies for swine waste by mandating utilities to purchase Renewable Energy Credits (REC) generated from swine waste. The Bill also provides a 35% State tax credit in addition to the Federal 30% tax credit.

Spurred by the availability of the NC Green Business Fund grants from the 2009 American Resource Recovery Act, Withers & Ravenel conceived the 600kW renewable energy project and assembled the project team, which included developer AgPower Partner, Withers & Ravenel engineers, and Barnhill General Contractors.

The project was able to receive over $2 million dollars in grants and tax credits, including a $500,000 grant from the NC Department of Energy and $1.5 million grant from the US Treasury. The Owner, Billy Storms, was able to finance the balance of the project cost through a loan with the Cape Fear Farm Credit Association.

Storms Farm Digester Site

Storms Farm Digester Site

Engineering a Plan for the System

In North Carolina, swine farms flush the houses with water in a closed system with a lagoon providing storage and treatment of waste which is then applied to crops. With this process, the waste is diluted to around 1-2% solids.  However, in order to reduce the water content for more efficient temperature control of the anaerobic digestion, the waste needs to be between 5-10% solids.

With the implementation of scraper technology, swine waste volume was significantly reduced by eliminating the added liquid from the flushing system.  This made the Storms Farm much less reliant on the volume required in the existing lagoons, reduced the required size of the anaerobic digester, providing benefits to both the waste handling concerns and to energy production.  The scraper system also reduced the amount of ammonia gas in the barns, which is beneficial to animal and human worker health.

Most digester systems for swine manure in North Carolina have relied on ambient covered lagoons. However, at Storms Farm, with the scale of a 600 acre farm and swine houses separated by as much as a mile, it was not cost-effective to build and cover a new lagoon to treat the waste using anaerobic digestion.  The distance between the 23 barn complex made it problematic to pump waste because of build-up in the pipe known to cause maintenance and failure problems.

After review of viable technologies, Withers & Ravenel recommended DVO Anaerobic Digesters to supply the digester technology for Storms Farm. DVO has an extensive tract record using their patented mixed plug-flow digester technology on dairy farms, but there was no comparable swine waste facilities using mesophilic digestion in the US.   Europe has a substantial number of facilities that use swine manure mixed with other substrates, but there was no reliable source of data for the gas yield using solely swine waste substrate.

As a result, Withers & Ravenel took multiple manure samples from local farms and had them tested to help estimate the biogas yield. Even with this data, there was very little information to collaborate the projected biogas yield. After all alternatives were evaluated, the most cost-effective, efficient option was to construct a heated mesophilic digester system with cogeneration and to convert the barns to scraper manure removal systems.

Receiving Pit and Generator Building

Receiving Pit and Generator Building

Construction Issues

Geotechnical borings were done and revealed the need to raise the digester above grade due to a high ground water table. This required sloping the backfill around the tank as insulation to maintain the needed 95 degree temperature in the mesophilic process.  The report also revealed the need to pre-load the site to avoid potential settling of the digester and cogeneration building.  This additional grading and site work was necessary from the original conceptual site plan.

The Digester Operation

The scraper system scraps the waste to a gravity collection system and storage tanks behind each barn. Two vacuum trucks and drivers empty each of the 23 tanks daily to collect the manure collected from each of the barns, drive to the digester facility and empty the manure into the influent pump station.

Manure is pumped into the  1.1 million gallon in-ground concrete digester where the temperatures are maintained above 95 degrees (mesophilic) and the natural occurring anaerobic bacteria destroy the volatile solids, produce the bio-gas containing 65% methane, kill pathogens, and produce a high quality inorganic waste product virtually pathogen and odor free for storage and, eventually, land application as fertilizer. At Storms Farms, about 60,000 gallons of swine waste is processed each day. The biogas is “scrubbed” of corrosive components and combusted in an 845 HP gas driven engine/generator integrated system provided by Martin Machinery, from Latham, Missouri.

The digester produces wastewater that is free of pathogens and odors and removes 90% of the phosphorus and 75%  of ammonia nitrogen.  The electricity – enough to power over 300 homes – is sold to North Carolina Electric Membership Corp.’s grid network.

Through this design, Withers & Ravenel was able to develop Storms Farm into the largest swine biogas renewable facility in North Carolina, generating 600kW of power with an operating capacity of 95%.

Generator Room

Generator Room

The volume reduction due to the implementation of the scraper system and digestion process has allowed the treated effluent to be returned to one of the existing lagoons, reducing the dependence on the original six lagoons on the site.

Future projects to remove the inorganic solids remaining in the effluent by dewatering and to treat for additional phosphorous and ammonia nitrogen removal are in the planning stages in order to meet the additional requirements of an EST standard farm.

What was the Owner’s involvement?

Billy Storms, owner of Storms Farms was instrumental in getting the Project off the ground, through financing the project, through the willingness to change the method of manure management and by accepting the technological challenge of running what is, essentially, a small wastewater treatment and power plant. He was a true partner in the project and was directly responsible for the selection and installation of the manure scraper system in all of the barns, implementing the operations of the truck collection system, the digester and generator systems as part of the farm operations.

Storms Swine Waste Ribbon Cutting

Billy Storms cuts ribbon at Opening Ceremony; team members look on

What can we learn from this project?

This project demonstrates a method to economically build new swine farms without total dependence on the historical open air lagoon treatment system, and flushing system collection methods, a conversion that is necessary to meet the State EST standards. The system also develops renewable energy meeting the goals in Senate Bill 3 requiring swine waste to be utilized in a percent of the production of renewable energy.

However, because of the cost, risk, and complexity of the project, its applicability may be limited to a handful of existing farms in North Carolina.  Larger farms, preferably more than 50,000 animals, are required in order to have the scale to produce the amount of energy to have an economical rate of return on investment.

Thanks, Withers & Ravenel, for the detailed project description. Your turn: Thoughts? Comments? Questions for the team?  Shoot me an email or post in the comments below.

Photos (c) Withers & Ravenel; Pig outline courtesy Pixabay.

Of Bridges, Biofuels, and Buildings (Engineering Excellence Awards)

As I noted earlier this week, the ACEC of North Carolina’s Engineering Excellence Awards gala was held last month. 13 amazing projects were awarded recognition, including projects involving environmental and coastal issues, higher education facilities, and government projects.

Each project was important, unique, or challenging in some manner. In my next post, I will highlight one of the most unusual– the Swine Farm Biogas project by Withers & Ravenel.  In the meantime, here are all of the winners, which I’ve loosely sorted into categories:

Mingo Creek Trail Bridge

Mingo Creek Trail Bridge

Coastal & Environmental projects

The Karen Beasley Sea Turtle Rescue and Rehabilitation Center, Surf City, NC (Cavanaugh & Associates)

Sea Bright to Manasquan Profile Survey, NJ (McKim & Creed)

American Tobacco Trail Pedestrian Bridge, Durham, NC (Parsons Brinckerhoff)

Mingo Creek Trail, Knightdale, NC (Stewart)

Town of Hillsborough Riverwalk, Hillsborough, NC (Summit Design and Engineering Services)

Swine Farms Biogas Renewable Energy Project, Bladenboro, NC (Withers & Ravenel)

 

Marsico Hall at UNC

Marsico Hall at UNC

Campus & Higher Education projects

South Halls Renovation, Penn State, University Park, PA (Clark Nexsen)

Science & Technology Building, Fayetteville State University, Fayetteville, NC (McKim & Creed)

Marsico Hall, University of North Carolina, Chapel Hill, NC (Mulkey Engineers & Consultants)

Military, Municipal, & Highway projects

Infantry Squad Battle Course, Marine Corps Base Camp Lejeune, Jacksonville, NC (Catlin Engineers and Scientists)

Carolina Field of Honor War Memorial, Kernersville, NC (Woolpert)

Broad Avenue Bus Terminal, High Point, NC (Mulkey Engineers & Consultants)

NC DOT Land Application of Concrete Byproducts, NC (S&ME)

The diversity of the award-winning projects was very clear, as even a cursory review of the projects demonstrates.  I recommend you follow the links to the specific projects to see some great photos and hear more about the projects in detail.

In the meantime, tell me what project you would have given the “best in show” award to if you were the judge.  Or, was a project left out of the awards that you thought superior to some of these?  Share your thoughts about both these projects, and any others that you think should have made the cut, in the comments section.

Photo credits:  Mingo Creek Bridge by James Willamor; Marsico Hall by Bbfd

Architects & Engineers – Liaising With Contractors (guest post)

Today’s guest post is by David Morrison.  David has worked on both sides of the construction site during his time in renovation.  Having stepped from the gravel pit into the office a few years ago, David currently now works with UK Tool Centre, liaising with the industry on their behalf.

Working as a site engineer or lead architect has many challenges and is undoubtedly one of the toughest roles, interwoven around effective communication skills with the clients as well as the site contractors, subcontractors and suppliers.

Since maintaining discipline and accountability is at the core of any successful venture, the same is true for a construction site also. The site engineer plays the “unwanted” role of implementing carrot and stick policy, awarding the effective contractor and dealing with the laggard.

carrot with club

 

For those beginning their engineering and architectural careers, or for those who still struggle to maintain a tight ship when dealing with contractors, there are a number of things to keep in mind.

a.)    Organizing Self - The way a site engineer organizes his work plays a very important role in meeting the final objective and let the workplace run as a team. The first and most important thing is to set an example by doing things in the same manner as you are requiring and expecting from the contractors.

b.)    Be Clear - A site engineer must ensure that the contractors have clear instructions, drawings and specifications related to their work. Otherwise the “garbage in; garbage out” rule shall be applicable to the final outcome.

c.)     Work Milestones - A site engineer should coordinate with the general contractor, who in turn should use professional project management tools, define work milestones and interact with the subcontractors to keep an eye on their timely completion. If any issues arise, they must be addressed quickly, so that the contractor or subcontractor’s work is not delayed.

d.)    Performance Appraisal - Informing  a contractor of his performance quality is only half the job; informing him in a timely manner is the remaining half. The site engineer should develop methods of regular assessment of work of each prime contractor, and should include this information in regular project meetings. This allows the site contractor to timely identify the gaps (both related to man and machine) in his work and to take action to complete the work successfully.

e.)    Teamwork, Motivation and Inspiration - To foster teamwork among various site contractors, a site engineer should know how to dig into his own experience of similar works. He should always work to motivate them by giving good and bad examples out of his experience. A well experienced site engineer always have lots of good advice from his earlier encounters to inspire the contractors and give them potential solutions to difficult tasks and situations.

f.)     Prompt Payments - A site engineer must always ensure that as per contractual terms with contractors the payment for the various milestones must be promptly processed and done without any delay. This is of utmost importance in getting the work done from contractors on a construction site.

g.)    Safety - A site engineer must always ensure that contractors shall never compromise on safety and security rules to expedite the work. A bad accident can be devastating, to the individuals involved and also to the project schedule.

h.)    Friendship, Philosophy and Guidance - A site engineer should know how to work as a friend-philosopher and guide to the contractors and must not always act as bully. After all, the contractor may have some genuine issues with the design team’s performance as well.

Advice for construction is ten to the dozen and there are a lot of potential misguiding mantras out there.  One of the most useful to take into account has always been: “It may take a lifetime to learn the ways to deal with contractors on-site, and still a lot will be left to learn.”

 Thanks David.  Now it’s your turn.  Thoughts, comments, questions?  Share in the comment section below.

Photo courtesy Teaching Underground.

 

When Running a Project, Don’t Think Like an Architect! (guest post)(Tue Tip)

Today, we welcome back Christopher G. Hill as guest author.  Chris is a LEED AP, Virginia Supreme Court certified mediator, lawyer and owner of the Richmond, VA firm, The Law Office of Christopher G. Hill, PC. Chris has been nominated and elected by his peers to Virginia’s Legal Elite in the Construction Law category on multiple occasions and is a member of the Virginia Super Lawyers “Rising Stars” for 2011 and 2012. He concentrates his practice on mechanic’s liens, contract review and consulting, occupational safety issues (VOSH and OSHA), and risk management for construction professionals.  

Chris authors the Construction Law Musings blog where he discusses legal and policy issues relevant to construction professionals. Additionally, Chris is active in the Associated General Contractors of Virginia and the Board of Governors of Construction Law and Public Contracts Section of the Virginia State Bar.  Most importantly, Chris’ blog was a personal inspiration to me as I set about my own blog back in 2009.  Welcome Chris!

Chris Hill
First and foremost, thanks to my pal Melissa for the opportunity to post here at her great blog.

Now that the formalities are out of the way, I will explain the title of this guest offering.  When Melissa first contacted me for my thoughts on poor project management from the contractor’s perspective, my first thought on how to avoid causing friction was “Don’t think like an architect.”

Before you flip the switch and head off for another post, possibly even another blog, hear me out.  Yes, I know that much of the audience for this piece is likely to be architects and other design professionals.  Yes, I know that all of you try hard.  But no, not all of you can run a job smoothly when acting as an Owner’s representative on a project (as opposed to designing a great building).  I’m here to help with my “musings” (see how I did that?) gained from years of representing the folks that you all seem to think are trying to ruin a project:  contractors and subcontractors.

The main thing that both “sides” of this equation need to remember is that you are all in this together.  Without your approval, the GC (and by extension the subcontractors and suppliers) on the project won’t get paid.  Without the GC and its cohorts, you, the architect, will have to listen to an Owner complain about the pace of the project and the fact that you aren’t running the project how that Owner wants it run.  See? All of us are in the same boat.

Failing to row in the same direction (to continue to beat this metaphor over the head) as the GC and seeing the GC as one that seeks to undermine your beautiful and artistic design sensibilities can only undermine those sensibilities.  GC’s and subcontractors, if asked nicely early on, can give you great insights into the scheduling, proper materials, and even the best and most efficient building design.

For example, an HVAC subcontractor can help you with the ductwork design in the beginning so that later on you aren’t barking at the GC because the subcontractor requested a change order (now waiting on your desk for approval) due to the fact that a load bearing wall would have to be moved in order for the ducts to go where you wanted them.  This minor bit of early discussion avoids the issue and keeps the GC and its subs happy, keeps the project on track and avoids messy things like liens and bond claims.

Failure to consult early and often, in a cooperative manner, leads to grumpy GC’s, ticked off subs, and a project that slows to a glacial pace.  This keeps everyone, including you, from being paid.

I could continue to rant, but you are smart folks.  You can do all of that engineering type math and all of that geometry and work with CAD that I decided was too hard so I went to law school.  You get the point: you and those that perform the construction at your project are not adversaries.  Yes, you represent the owner and want to make sure that the building is built right.  However, the best way to do this is to consult early and often.  Free information flow is the best way to keep everyone happy and everyone paid.

Thanks again to Melissa for letting me rant.

Thanks, Chris.  Ranting with a purpose is always welcome on my blog!  Readers, it is your turn.  Questions, comments, or rants for Chris or me?  Comment below.

Wind Energy Gets a Second Breath of Life (News Note)

wind trubines

Have you been following the “fiscal cliff” debacle?  Unless you spent the holiday season in a cave, the answer is probably YES.  One interesting detail tucked away in the recently passed compromise legislation is the renewal of the Renewable Energy Production Tax Credit (PTC) for wind power, now extended through 2013.

The PTC awards a 2.2 cents per kilowatt hour tax credit for wind, geothermal and closed-loop biomass and 1.1 cents per kilowatt hour for other renewable energy technologies. This lasts for 10 years for most technologies, including wind.  Alternatively, companies can request a lump-sum payment of 30% of the wind construction cost as a tax credit once the wind turbine starts producing power.

Also new for 2013, companies are allowed to claim the credit if construction begins before the end of this year.  Previously, the facility had to be placed in service (i.e., operating) before the end of the year.

According to the folks at Green-Buildings.com, the extension of the renewable energy credit should boost wind energy construction, at least for the first half of 2013.

What is your opinion of the tax incentives for wind energy?  Yeah or Nay? Share in the comment section, below.

Photo (c) berent

 

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