For a wastewater plant, a biogas plant or a farm that has to get rid of difficult residue, that residue could become a fuel rather than only a cost. Jenja is designed to take difficult, ash-rich residues.
High-ash residues are a cost and a liability. Worldwide, an estimated 41% of waste is burned in the open.42 Fine particles from burning household waste in the open cause an estimated 270,000 premature adult deaths a year.43
In Germany, land spreading of sewage sludge from larger plants is being phased out. An operator facing that calendar needs a route that is not land spreading.
land application of sewage sludge ends in Germany for plants above 100,000 population equivalents, and from 1 Jan 2032 above 50,000.44
The residue could become fuel instead of a disposal cost. Its ash still has to be managed. How much the environment gains depends on what happens to the residue today.
Each residue has its own fate today, and its own possible route.
| Feedstock | Current fate | Jenja pathway | Potential impact |
|---|---|---|---|
| Digestate | Already broken down without air before it reaches us. Because most of its methane was already captured upstream, a large methane saving cannot be assumed for digestate. | The earlier X10 test unit turned digestate pellets into a fuel gas. | A route that is not land spreading. Site specific |
| Sewage sludge | Land spreading or incineration. In Germany, land spreading is ending for sludge from larger plants.45 | Not yet measured on Jenja. No sludge test on any test unit is documented. | Potentially a route that does not depend on land spreading. Requires its own ash and residue testing before any claim. Site specific |
| Straw | Rice residues, which include straw, are most often burned, because burning is simple and low-cost.46 | Straw causes severe slagging in many gasifiers.47 The earlier X5 test unit in Zittau ran straw tests. | A route other than open burning. Site specific |
On wet feedstock. Jenja can be supplied with a drying unit, which is the first step of the process: wet feedstocks are dried before gasification, and ready-made dry pellets do not need this step. Moisture still affects energy demand, throughput and the economics, and it is not free.
Less open burning. Residue that becomes fuel is residue that is not burned in the open, and its smoke never reaches the people nearby.
A route when the rules change. For sludge that can no longer go onto fields, Jenja could offer a route that does not depend on land spreading, once sludge has been tested on it.
The next step is a site with a difficult residue and a known current fate, where Jenja runs and what goes in and comes out is measured. That one measurement unlocks the rest of this pathway.
A possible next chapter. Germany's sewage sludge ordinance requires phosphorus recovery from 2029 for sludge above a set phosphorus content.48 Recovering phosphorus from Jenja's ash or solid residue is a possible future pathway. It has not yet been tested.