Sampling methods and locations for GNF

A controller of an agricultural operation shall ensure when sampling GNF that the rules in this section are complied with.

3.1 GNF Sampling Equipment and Methods

When taking a sample from a permanent GNF storage facility, you must use the bucket toss method or the dipper method as described below in sections 3.1.1 and 3.1.2.

For sampling from permanent GNF storage facilities, take at least the number of sub-samples required by section 3.3 from different locations of the storage facility and combine these sub-samples into a larger container (composite) where they must be mixed thoroughly (homogenised). This composite sample must then be transferred to a clean sample bottle for shipment to the laboratory for analysis.

For sampling from GNF transfer systems, the sample must not be taken during the start-up or shut-down of the GNF transfer system. A number of sub samples must be taken and be combined together.

3.1.1 Bucket-Toss

Attach a rope to a small plastic bucket and then throw the bucket out into the facility, let it sink and then carefully pull the bucket back.

Swirl the bucket and then pour about 1 litre of the contents into a second clean plastic bucket. Repeat this from different locations around the perimeter of the facility until at least the required number of sub-samples under section 3.3 has been taken.

3.1.2 Dipper

Tape a clean plastic wide-mouth bottle (250-1000 ml capacity) securely to a pole that is long enough to reach over any scum collected at the edge of the facility. Remove, at least, the number of sub-samples required by section 3.3 and pour them into a clean plastic bucket. Once all of the sub-samples have been taken, mix the bucket contents and transfer to sample bottles for analysis.

3.2 Requirements for Agitation

If agitation is required by the Regulation it must be carried out using a mechanical mixing device, aeration device or using a hauling truck's pumping system. It must provide a well-mixed material for sampling.

3.3 Number of GNF Sub-Samples for Analysis

A minimum of five sub-samples must be collected and composited for each sample. The number of sub-samples required is based on the volume to be removed for land application. Table 1 sets out the minimum number of sub-samples required per composite sample. Where the volume of GNF removed for land application in Column 1 applies, the minimum number of sub-samples opposite it in Column 2 must be taken.

Composites must be well-mixed (homogenized) and transferred to properly labelled laboratory bottle(s). Information concerning the sample volume required, the type of sample bottles to be used and the appropriate preservative needed, based on the analytical test(s) required must be obtained from the person operating the laboratory.

Table 1. Minimum Number of GNF Sub-Samples per Composite for Different Land Application Volumes