Starting status: three full scale one-stage digesters
2018 initiatives (€10M investment)
Two-stage digestion system
Thermal pressure hydrolysis (TPH) between the two stages
System for struvite precipitation
System for ammonium sulfate production
First stage
Substrates: sewage sludge and grease separator contents
Second stage
Additional substrate: primary sludge
Reuse of TPH heat for temperin
THP
Cell lysis
Higher availability of dissolved
carbon compounds
Higher methane yield in second digestion stage
Increase in dissolved phosphate and ammonium concentration
Within the project, the optimal mix of struvite and ammonium sulfate will be determined via ‘Communities of Prac ce’ to engage with local farmers.
Relevant Data
32.000
Population Equivalent
30 Ha
of Agriculture
Demo site:
Braunschweig WWTP
Relevant sectors
Industry
Agriculture
Chemistry industry
Key innovations & actions
Follow-up a full scale nutrient and energy recovery from sewage sludge combining thermal hydrolysis and two-stage digestion together with ammonia stripping and struvite precipitation from the WWTP. Investigation of quality and quantity of recyclates produced
Effcient energy (biogas and heat) management for hydrolysis and digestion including seasonal demand
Set up and optimise a new nutrient recycling scheme. Requirement definition of a targeted product (grain size, moisture, chemical composition, quality variance over the year, optimal mix of struvite and ammonia sulfate) in order to increase acceptance