Industrial scale plant for sewage sludge treatment by hydrothermal carbonization in Jining, China and phosphate recovery by Terranova Ultra HTC process
Buttmann, M., Terranova Energy, Germany
(free)
Abstract:
In Jining/China 14.000 t of dewatered sewage sludge are treated by TerraNova® Ultra Hydrothermal
Carbonization (HTC) technology per year to generate a solid fuel for energy production.
The technology is economically attractive as the sewage sludge is considerably reduced in mass due
to the loss of dry matter (DM) during HTC and subsequent purely mechanical dewatering of up to 70%
DM.
Furthermore, TerraNova® Ultra enables the recovery of Phosphorous from sewage sludge. By
adjusting the pH level during the HTC process, Phosphorous is leached into the liquid phase and
transferred into the filtrate. By adding CSH minerals to the filtrate >80% of the Phosphorous is recovered
as fertilizer product. The moderate use of reagents and the one-step process allow for low specific cost.
In the lecture, the energy- and mass- balance of TerraNova® Ultra, the Phosphorous recycling process
and the fertilizer specification as well as typical project economics for an installation in Europe will be
presented.
Introduction:
The economic disposal of sewage sludge is an increasing challenge for municipalities due to the
increase of environmental standards and the closing down of traditional disposal paths. Mass
reduction by anaerobic treatment or thermal sludge drying are solutions widely seen but with some
disadvantages in terms of energy and cost efficiency.
The TerraNova® Ultra technology includes a thermo-chemical sludge conditioning followed by an
ultra-dewatering step for highly energy efficient mass reduction. The final product is sterilized with low
water content and can be used as CO2-neutral fuel for energy production or for agricultural
application.
Phosphorous can be recovered from sewage sludge within the TerraNova® Ultra process at little cost
in form of a Calcium-based recycling product.
