After the hydrothermal carbonisation process, the water-soluble nutrients, previously contained in the fresh processed material, are dissolved in the HTC process water. Nutrients can thus be concentrated and used as a basis to produce liquid complex fertilizer applicable for crops fertigation. In the case of the Ingelia plant operating in Valencia, the competent authorities have authorized the company to permanently use the process water for citrus groves fertigation. It is important to underline that the produced water is sterile, because the process temperature ranges between 180 and 200 °C.
The liquid fertilizer quality
The list below reports the tests results of the HTC water analysys, before any concentration and post treatment
|Dry Matter||% tot||2-4%|
|Organic Matter||% tot||1.7-3%|
|pH:||–||5.8 – 6.5|
|Tot N||% dry||3-4%|
|Conductivity||dS / m at 25 ºC||12-17|
|Na||% Dry||2 – 4|
|K||% Dry||4 – 9|
|Mg||% Dry||1.5 – 2.5|
|Ca||% Dry||5.7 – 9|
The produced water contains a valuable amount of potassium, calcium and Magnesium, suitable for agriculture application. In addition, the heavy metals content presents very low values, which ensure a large applicability of this product.