(Image: Courtesy Landia)
Landia’s GasMix state of the art biogas digester mixing technology has just been successfully installed at North State Rendering in Oroville, California for the best possible biogas yield. To achieve that, very thorough mixing of the bio-reactor is essential.
Only by achieving heterogenous mixing can the micro-organisms that produce biogas methane get at all the food they can extract from the substrate, and the GasMix system (which we have described previously here) is particularly ingenious in the way it achieves that.
The rendering industry is seldom publicized. What it does is not exactly glamorous and little usually happens in the industry to promote more general interest. However, at North State Rendering they now have something which is making them a star of the U.S. biogas industry.
Biogas Energy is the company that has been contracted to build an anaerobic digestion facility for North State Energy, where Landia's gas mixing equipment is helping to pay peak dividends.
They are now achieving uninterrupted biogas production, generating electricity 24/7, fuelling the rendering company's trucks, and creating heat to run their boilers. Plus, they have estimated that they will be able to reduce by 75% their diesel costs, by introducing a gas-cleaning skid to create a natural gas grid-ready quality biomethane, that is then compressed to become their own source of CNG fuel.
Rendering waste is a high energy producing substrate, so their bio-reactor produces a lot of energy. This means so that the economic benefit of this new plant is seriously cutting their business costs.
Not only that, at times when they do not need all the power to plant produces, they can further process and sell the spare energy, and the plant also provides a form of wastewater treatment ready for its discharge and use.
This has to be a notable first for the industry in North America!
Brian Gannon of Biogas Energy said recently that:
"For a rendering plant, biogas is a natural fit”.
“North State Rendering were looking for ways to cut costs, secure new waste supply contracts, and improve wastewater treatment, so creating their own on-site biogas facility was a wise move. Fuel and energy are a significant operational cost for the business, so investing in technology that eliminates electricity bills, slashes diesel costs and reduces natural gas imports all makes sense. Modifying the anaerobic digestion process to integrate with a rendering plant took some fine tuning, including a very positive modification to the digester’s mixing system, but now, we see how we got it right”.
Renderers commonly find that food waste from kitchens, grease trap waste, plus restaurant and food processing waste, can be expensive to render, and yet it is ideal for anaerobic digestion. The biogas plant allows them to divert such wastes from their existing and new waste disposal contracts, freeing up rendering capacity for rendering more suitable materials.
By configuring their waste reception facility flexibly they now divert their existing incoming materials to the most efficient type of process, either to the rendering plant or to the biogas plant.
The digester processes materials such as, food and yard waste and high-liquid content grease trap materials. Wastewater produced by the rendering process is also sent to the biogas plant, as is also any dead livestock tissue, after suitable preparation. This is particularly useful during hot weather, when rendering may become difficult due to the rapid degradation of this material.
Brian Gannon also said:
“We had been using submersible propeller mixers inside our main digester, but with our re-design of the tank, we switched to a new system that meets all of our needs. One of the main issues with submersible digester mixing systems is that the equipment is inside the tank, which from a maintenance point of view is a nightmare. The downtime caused by having to open the digester to lift the mixers out for repairs and maintenance caused serious process interruptions and safety issues."
“We now have a Landia digester mixing system, which is mounted externally, so maintenance is much easier. Even during commissioning when the AD biology was at a delicate stage, we were able to carry out some tweaks without any interruption whatsoever to the biogas production process. With submersible mixers we would have had to start over again, which would have been very expensive and used up a ton of manpower”.
Ease of maintenance is not the only benefit from the Landia GasMix system, Brian also explains that the Landia (patent-pending) system is able to agitate and mix into the entirety of the digester tank (even one as big as this - at 64 feet high!), whereas competing systems frequently fail to prevent a hard-pan (or "crust") from forming on the surface of the tank’s contents.
Brian also said that:
“The anaerobic digestion facility is designed to process a very wide range of feedstock”, he said, “so its pumps and mixers have to cope. The Landia chopper pumps, which form part of the GasMix system, are absolute troopers. They just keep on working. We wouldn’t be achieving what we are now without them”.
The GasMix system installed comprises, two 30-HP chopper pumps and a self-aspirating system. That, coupled to a clever sequencing control system ensures that the action of the meathnogenic micro-organisms is much more effective in reducing the volatile organic solids content to produce more methane, and does it in a much reduced time period.
Landia’s GasMix which is uniquely designed specifically for AD and biogas reactors, is simple to operate, and has a low energy requirement, because it only needs to run for up to 30% of the installed capacity of the equipment, in normal use.
Brian Gannon concluded:
“Renderers have a big head-start over other companies trying to develop new waste-to-energy facilities. Unlike newcomers, renderers already have the necessary permits in place to process waste material. They also have the trucks to collect waste, and the energy consumption that biogas facilities can help fuel."
“As energy and fuel prices climb and wastewater discharge fees escalate, waste processors can turn waste into an asset. For Biogas Energy, our experience at North State Rendering and the introduction of Landia’s GasMix digester mixing system means that we can help our clients generate renewable energy with a system that maximizes production while facilitating operations and maintenance”.
For more information contact:
T: +1 (919) 466 0603
Biogas Energy: www.biogas-energy.com
T: +1 (815) 301 3432