Decommissioning and/or Recommissioning Existing Nutrient Storage Facilities
Table of Contents
There are many nutrient (e.g., manure) storage facilities in Ontario. For a number of reasons if the facility is damaged, no longer required for the operation or if a livestock operation has changed hands or has been eliminated an operator may wish to decommission a nutrient storage facility temporarily or indefinitely (Figure 1).
The Nutrient Management Act, 2002 (NMA), does not regulate the decommissioning of nutrient storage facilities in Ontario. This Factsheet offers some guidance for dealing with unused solid and liquid nutrient storage facilities, providing suggestions for:
An improperly decommissioned nutrient storage facility can be a safety hazard. Children and adults are at risk of being hurt or even killed if the hazards are severe enough. Falling into the storage and drowning are very real possibilities. As well, the storage facility may cause an adverse environmental impact on surface or subsurface water sources.
Figure 1. This unused manure tank is no longer environmentally sound. The excavator is in the process of demolishing and burying the structural materials on-site.
When buying an existing farm, be aware that nutrient storage facilities may be hidden below the soil surface or covered with earth or a concrete pad. There have been cases in Ontario where large equipment driving over the top of a nutrient storage facility has caused the storage to collapse, creating a very hazardous situation.
Earthen manure storages may look like water ponds over time.
There is a good chance that a livestock operation includes a liquid and/or solid nutrient storage on site. For liquid storages, look for visible cues that indicate that a storage facility exists, such as access holes or old fences. It is important to ask questions of previous owners about the farm's operations. These hidden facilities can represent a serious safety hazard. Take extra care if children have access to the area.
There is no limitation on how long a nutrient storage facility can be temporarily taken out of operation, as long as it is maintained in a state of good repair.
A poorly maintained or decommissioned nutrient storage facility contains nutrients that can become pollutants if a structural failure or overflowing occurs. In addition, these facilities can be a human safety hazard, especially if they have poorly maintained safety fences or access points.
OMAF recommends a periodic inspection of all nutrient storage facilities, whether they are used or not. The purpose of the inspection is to determine if they are structurally sound, if enough capacity exists to prevent overflowing and if all safety components, such as hatches, railings and fences, are present and in good repair.
Solid Nutrient Storage Facilities
In general, the storage of solid nutrients presents fewer environmental risks than the storage of liquid nutrients. However, if liquids (e.g., seepage, washwater, precipitations) accumulate in a solid nutrient storage facility, or runoff is not properly managed, a solid nutrient storage facility may pose as high a risk as a liquid nutrient storage facility. Conduct regular inspections of these facilities to verify their integrity and ensure that they manage potential runoff adequately.
Consider alternative uses or permanent decommissioning of a solid nutrient storage facility after the clean-up process. In most cases, this involves emptying the storage facility of nutrient materials (e.g., manure) using normal handling equipment. Manage the nutrient material according to a nutrient management strategy or plan, if your farm is phased-in under the NMA, or following best management practices (BMPs) for managing nutrients on farm.
Liquid Nutrient Storage Facilities
Liquid nutrient storage facilities often present higher risks than solid nutrient storage facilities. To minimize the risks, consider the following recommendations, where applicable:
Before permanently decommissioning a nutrient storage facility, consider alternate uses. For example, a solid nutrient storage facility could serve as a foundation for a covered hay storage structure or a machinery storage structure. It could store non-agricultural source material (NASM), if it meets the requirements of the NMA or Environmental Protection Act (EPA). For more details on storing NASM, see the OMAF Factsheet, Storage of Non-Agricultural Source Materials (NASM) in a Permanent Storage Facility, Order No. 12-069. If no alternate uses are available, OMAF recommends that the storage be properly decommissioned.
Permanently decommissioning a facility can be necessary when it:
While there are no specific decommissioning requirements under the NMA, follow these general guidelines for solid and liquid nutrient storage facilities:
Steel or Concrete Facilities
There are no specific Ministry of the Environment (MOE) decommissioning requirements for concrete nutrient storages if the concrete facility is dismantled and buried on-site. However, consider hiring a qualified demolition company to dismantle the storage. Further, ensure that burial of the material does not result in an adverse impact to ground- or surface water. Recycle any storage-facility building materials taken off-site or dispose of them at an MOE-approved facility.
For on-site decommissioning of steel or concrete facilities:
Earthen Storage Facilities
For on-site decommissioning of earthen storage facilities:
Before returning an existing nutrient storage facility to use, inspect the inside and outside of the facility.
Beware of potential hazardous gas trapped in storages that have not been used for a period of time. Before entering or going down into a storage facility, take all necessary safety precautions. For more information on hazardous gases, see the OMAF Factsheet, Hazardous Gases, Order No. 13-025.
To complete a thorough inspection, empty the storage facility and follow any instructions from the builder or engineering firm. Observe the level of the water table in this area before performing this work. Do not undertake this work when the water table is higher than the floor of the facility, unless provisions are in place to reduce the chance of structural damage (e.g., foundation drains installed, engineering review completed).
During the inspection, check the inside and outside of the tank, any liners and transfer systems. Look for any signs of damage such as:
Where pipe sections go through a wall or floor, such as part of a transfer system, ensure that joints between the pipe and tank wall/floor are watertight. If a tank includes a liner, assess the liner's integrity.
A storage facility that has not been used for a period of time may have damage that cannot be identified during a visual inspection and may leak to an existing drainage system outside the storage. It is best to find any outside drainage systems and install an observation/shut-off catch basin into the outlet of the drainage lines. If this is not possible during the filling of the storage, especially a liquid nutrient storage facility, it is important to both monitor the levels of the storage to ensure the system continues to fill, and to monitor the expected outlet of any drainage system that could affect the storage. Take immediate steps to remedy any problems.
For more information on observation stations and shut-off valves, see the OMAF Factsheet, Siting Requirements for Permanent Nutrient Storage Facilities, Order No. 12-065.
If there are any concerns about the integrity of the facility or associated liner and transfer system, hire an engineer to obtain professional advice.
The purpose of this Factsheet is to create an awareness of safety issues and possibilities regarding the re-use and decommissioning of nutrient storage facilities.
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