Percolation and Digestate


The on-site treatment of the percolate produced by municipal solid waste proves to be a more advantageous solution, from an economic point of view, than its transportation and disposal.

Landfill percolate is a contaminated liquid that can have varying chemical and physical qualities depending on the type of waste delivered and the characteristics of the landfill. Generally speaking, landfill leachate contains heavy metals, COD (in concentrations up to 30,000 mg / l), chlorides, sulphates and other pollutants including nitrogen, nitrates, ammonia and boron.

For the treatment of percolate BIOWASTE offers high energy efficiency systems, in particular machines that can use the biogas produced from waste or the cooling water of the cogeneration groups as energy source, usually in combination with membrane systems (osmosis inverse and ultrafiltration) and resin plants.


In addition to energy production, the biogas plant continuously produces large quantities of a by-product called digestate.

Digestate is a semi-solid material, containing variable quantities of dry matter, which has properties similar to an organic fertilizer given the amending properties and interesting contents of NPK /NPK stands for “nitrogen, phosphorus, and potassium,” the three nutrients that compose complete fertilizers. You may encounter these letters when reading the contents printed on bags of fertilizer.

For this reason, it is commonly distributed on agricultural soils, according to specific spreading plans. Digestate, compared to the raw material, is homogeneous, with a higher moisture content because part of the dry substance that has been biologically degraded, is demolished by bacteria for biogas production.

The organic substance that remains is more stable and contains elements of fertility, such as nitrogen, phosphorus and potassium, which can be usefully returned to the soil to provide nourishment to crops.

Enriched with fertility elements, such as nitrogen, phosphorus and potassium, the digestate is more homogeneous than the raw material on whose chemical composition it strictly depends.

After leaving the biogas installation, the digestate material is separated by screwpress. The solid fraction can be used faster than the manure in the field. A clarified fraction with ready nourishing effect for crops.