Cost-effectiveness for controlling emissions of Volatile Organic Compounds (VOC) in industrial waste gas depend on the characteristics of the gas emitted. SMEs affected by VOC emission Directive 99/13/EC (wood, printing, surface cleaning, dry cleaning, leather, vehicle refinishing) generate low and variable concentrations of several different VOCs in small volumes of waste air. This profile of VOC emissions is the focus of the new Industrial Emission Directive 2010/75/EU, but it shows the most techno-economic problems for VOC control.

GRABGAS uses rhizodegradation to treat small volumes of industrial waste air with low and variable concentrations of several different VOCs with a high removal efficiency to comply with directive emission limit values. Rhizodegradation uses plant roots, microorganisms and soil to biologically degrade VOC into CO2 and H2O. It can simultaneously degrade several VOC in very low concentrations or even when they are temporarily absent.

GRABGAS adapts to changing concentration of different pollutants, as well as to weekend and short holiday interruptions without losing removal efficiency. To make VOC mixtures more biodegradable, a solar photocatalytic pre-treatment using doped-TiO2 is applied before rhizodegradation. To support plant growth and solar photocatalysis with sunlight, GRABGAS is designed to be installed on industries’ roofs, following European green roof standards. Optimal air flow through the rhizofilter is be achieved by a substrate allowing root growth, high active surface for bacterial growth, permeability for air and VOC storage capacity. It keeps the internal temperature and moisture within constant ranges by appropriate sealing, insulation and drainage. With Green roofs, the top of buildings are covered by a layer of planted soil to improve the summer insulation of the building and thus improve energy efficiency.

GRABGAS is a special extensive green roof to cleans industrial waste gas thanks to the VOC rhizodegradation capacity of planted soil and photocatalysis.