On 26 January, AquaMinerals signed the Green Deal Topsurf – the other signatories included the Province of South Holland, Rijnland District Water Control Board, the municipality of Alphen aan de Rijn and, of course, Topsurf itself. In this way, AquaMinerals is backing a pilot project to counter land subsidence in peat-meadow areas: a big problem that we want to tackle from a regional perspective, in an innovative and environmentally-friendly manner.
The land in the peat-meadow area near Hazerswoude is subsiding by no less than one centimetre every year. The water control board can no longer deal with this long-term rate of subsidence. The phenomenon of course has very detrimental implications for dairy farmers, but also for the recreational opportunities in this unique nature area in the middle of the Randstad conurbation.
Topsurf has been working on a product to stop the subsidence for many years. Following extensive research the effort succeeded through the use of a unique combination of local, and mostly endemic, residuals. Concretely, this involves a special mixture of dredging spoil, manure and green waste. The product’s application has many additional benefits. Apart from elevating the land, it also leads to higher (grass) yields, local use of local resources, new economic activity and an enormous reduction of greenhouse gas emissions.
Over the past few years AquaMinerals has worked with Topsurf to examine the extent to which drinking water sector residuals could contribute to meeting this challenge. We discovered that pulverised carbon (structural material), lime sludge (ph control) and iron hydroxide (phosphorus fixation) could all play a role.
The pilot project will get underway this summer. We will follow a strict monitoring programme to research whether the positive lab and practical test results can be replicated on a large scale and over the long term.