Development and application of a quality control and assurance scheme for reusable soil
This paper describes the development of the market for reusable soil against the background of developing legislation. In the 1980s, the (re)use of lightly contaminated soil was prohibited in the Netherlands. The 1990s saw the advent of reuse policies at provincial level, where the concept of 'functionality' was embraced. Essentially, site-specific reuse standards were set, based on contaminant concentration levels. This propelled the establishment of soil-recycling facilities at a regional scale, which culminated in the establishment of the Dutch Association of Soil Recycling Facilities, now numbering 13.
The Dutch Building Materials Decree, which regulates the (re)use of primary and secondary materials, became fully effective in mid 1999. Technical procedures to assess soil quality, in terms of contaminant concentration and leachability, are strictly prescribed. The 2000s saw the advent of increased and formalised attention for quality control and assurance. For reusable soil, a certification scheme was developed incorporating the following elements:
- Input control and acceptance procedures, depending on soil quantity in the ranges < 100 tonnes, 100-2000 tonnes and 2000-50.000 tonnes.
- Sampling of the soil stockpiles, with quantity dependent strategies.
- Chemical analysis and leaching procedures.
- Soil qualification procedures.
- Soil certification and delivery to the customer.
All (including laboratory) procedures are audited on a regular basis by independent organisations. Typical (estimated) features of the reuse market for soil are collated in the Table below.
| ENTRY | DIMENSION | QUANTITY |
|---|---|---|
|
Reuse of untreated soil |
Mton/year |
9 |
|
Reuse according to certification scheme |
% |
30 |
|
Soil recycling facilities |
number |
30 |
|
Certified organisations |
number |
20 |
|
Total reuse costs |
Euro/ton |
2-7 |
|
Soil qualification costs (only) |
Euro/ton |
1-2 |
|
Certification costs (only) |
Euro/ton |
0.5 |
It is concluded that the use of a certification instrument allows for the reliable, sustainable and cost-effective reuse of soil. The use of the certification scheme has significantly enhanced customer confidence and compliance with legislation.