This is a somewhat complicated system. It took a lot of time and trial and error to make it what it is today.
This system handles the manure from Farms 2 and 3.
To explain the system properly we have to start in the barn with the cows.
When the cows are in the parlor being milked the alleys in the barn are scrapped (picture to the left) in to a holding pit at the end of the pen. (right picture)
We bed our barns with sand so the manure is full of sand when it enters the pit. Sand is the ultimate bedding from the standpoint of dairy cow health. Sand provides a healthy environment for the udder, keeps cows cleaner, and aids in cow traction on slick concrete. The sand is trucked to the farm from a gravel pit located near the farm.
Once the manure is in the pit at the end of the barn the sand needs to be taken out of it. For this process we use Sand-Manure Separators, from the McLanahan Corporation. Six separators total are used, four of the separators are located at farm 2 and there are two at farm 3.
Above is a sand separator from 3 different angles. The manure from the pit makes its way to the separator where recycled water is added in order to dilute the mixture, which gives the sand a chance to settle out. Once the sand it settled out of the manure it is augured out and stacked. At this point the manure is almost sand free. The separated sand that comes out of this process is stacked out of the way to drain and dry. In a couple months it will be ready to be reused under the heifers.
That leaves us with the manure. There are two options for the manure, haul it to the field for injection or it can be sent to the treatment plant. We have added another step in the treatment process with the addition of the methane digester. For more information on how the digester works please visit the methane digester page. After the digester the manure is pumped into our treatment plant. This part of our system is very similar to any Municipal Waste Facility that you would find in any larger city. As the manure enters the system ferric chloride is injected into it. Ferric chloride is used to bring the pH of the manure to 7.0, once the pH is neutralized a polymer is added. Polymer binds most of the nutrients and the fiber in the manure together, resulting in a gooey coagulation of solids (containing fibers and nutrients) and a tea colored water (the tea coloring comes from the ferric chloride). The next step is to separate the water from the solids by running it over and through a belt filter press.
Look at the wall of pipes in the picture above left. This is our solution to mixing the ferric chloride and polymer in the manure stream. With some help Craig came up with this idea of 90 degree turns after having trouble with an in-line mixer. The in-line mixer would plug up with cow hair, ear tags, or anything else that made it into the manure stream. The turns in the pipes cause turbulence with no restrictions.
(middle picture above) Demonstrates the manure with ferric chloride and polymer in it as it is starts into the belt press. You can see that the water is separated from the solids.
(above right) Side view of the belt press. Showing the rolls and belts that squeeze the water out of the solids.
(Left) What the manure looks like before it goes through the treatment plant. All the nutrients are still in it.
(Right) Clean water that comes out of the treatment plant. Remember that the color that is in the water is a stain that comes from the ferric chloride, which is a product of the iron industry. This is a nutrient free product.
(Below) The nutrients are now in the form of a fiber cake. (solids)
At this stage in the process we have 2 products, fiber cake and clear water. The clean water is recycled and sent back up to the front of the farm to flush the parlor floors and to clean the sand from the manure. All of the extra water is sent to the lagoon. Where it is collected until it is used to irrigate the crops. Our lagoon water is treated to reduce any smell that may be associated with it.
The fiber cake ends up in one of two places. It is either spread on the field as fertilizer or it is composted. Morgan Composting of Sears, MI is responsible for the composting end of our system. They are the ones that lay it out in rows, turn it, and sell it. If you are interested in compost please contact Morgan Composting, you can find their information on their website dairydoo.com
(Above left) Drop irrigation.
(Above Middle) Truck spreader that is being loaded with fiber that will be hauled to the field. The dense nature of the fiber makes it easy to haul long distances.
(Above Right) Compost being turned.