Liquid manure pit closure: guidelines for risk management
Animal waste facility closure can be tricky. Here is some guidance for a safe undertaking.
Farms and farm enterprises change over time. As your farm acquires property or shifts goals you may find that you have an unwanted liquid manure storage facility on your property. These facilities can be an unnecessary risk to people and the environment. Please note that this guidance to close these facilities and additional assistance isn’t exhaustive and should serve to help aid the process of closing these facilities but should not be your only source of assistance.
Communicate with farm staff where and when there will be earth moving activities. Also, communicate that the facility is not to be used for waste disposal in the future. Fence the area where there will be work and/or post warning signs. Be sure to use gas monitors during waste removal activities. Use appropriate lock-out-tag-out procedures during confined space entry while cleaning and closing the facility. According to the Occupational Safety and Health Administration (OSHA) lock-out-tag-out is a process used to “ensure that the machine or equipment is stopped, isolated from all potentially hazardous energy sources and locked out before employees perform any servicing or maintenance where the unexpected energization or start-up of the machine or equipment or release of stored energy could cause injury.”
Remove existing waste
Agitate and pump liquid and slurry waste. If the pit is lined with a membrane or earthen liner, be sure to use caution to ensure the liner is not damaged during agitation and waste removal. Remove the sludge with the same precautions to prevent liner damage. Transfer the waste to another storage facility, considering the impact on capacity the transferred waste would cause, or utilize all waste and soil removed from the facility in accordance with the Natural Resource Conservation Service (NRCS) Conservation Practice Standard(CPS) Nutrient Management (Code 590). This will require testing of the waste material at a laboratory.
Remove structural components
There are three options for decommissioning liquid waste storage ponds that are in the ground: breaching the embankment impoundments, backfilling excavated impoundments, or conversion to freshwater storage. You can find a detailed description if these processes in the NRCS Field Technical Guide.
Facilities that are fabricated, such as above or below ground manure storage tanks, should be demolished or disassembled. Temporarily store the disassembled materials in a safe way to prevent harm to humans or environment until disposal. Materials may be taken to a local or state approved offsite location such as a landfill or buried onsite following the guidance in the practice standard.
Permitted Concentrated Animal Feeding Operation (CAFO) farms
Contact EGLE and let them know you will be removing the facility. If your manure management plan contains the facility, you may need to edit your plan. The State of Michigan CAFO permit requires that waste storage facility closures utilize the guidance for closure techniques contained in NRCS Conservation Practice Standard No. 360, Waste Facility Closure.
If your manure management plan contains the facility, you may need to edit your plan. Be sure to calculate the storage capacity and manure to be produced. At this time, there do not appear to be regulations for non-CAFO farms regarding a required closure process. If your farm is Michigan Agriculture Environmental Assurance Program (MAEAP) verified or you desire to be, MAEAP standards require closure of liquid waste storage facilites according to NRCS standard No. 360 for Farmstead and Livestock verification.
A word of caution
Waste storage facilities that are unmaintained or abandoned at any farm pose the risk of leakage or breach, which can be detrimental to the environment as well as a liability to the producer. Producers may receive violations and/or be held liable for the costs of environmental remediation needed due to a discharge from an abandoned or improperly closed waste storage facility. Performing a formal waste storage facility closure is an excellent way to reduce environmental risk and liability on any farms that have waste storage facilities on site.