Developed by Dutch Plantin, the DP Optima double-layer coco slabs were found to require 10 to 20 percent less water and fertilizer feed than rock wool slabs of similar dimensions, while producing the same tomato yield during greenhouse trials carried out over the course of 2011. The slabs provide both financial and environmental benefits, as they can be disposed as low-cost compostable waste or used as fuel in bio-energy plants. Although water supply in North America is not usually an issue, less drainage means less water to be cleaned and decontaminated, resulting in smaller installations. It also means fewer waste nutrients seeping into the environment.