Britt Nilsson of Kemira Kemi AB presented on using Kemira's BDP product to recover an unstable anaerobic digester. The digester was processing crops, maize, sugar beet, and animal feed residuals but became unstable due to a lack of nitrogen. Addition of BDP in a "kick-dose" rapidly reduced volatile fatty acid levels from 19,000 mg/L to 4,000 mg/L within a week and to 400 mg/L after two weeks, recovering the digester process. A case study showed how a single dose of BDP was able to restabilize an overloaded digester. BDP kick doses can recover overloaded digesters, stabilize performance, and

1. OPERATIONAL PERFORMANCE –
ADDITIVES AND PLANT STABILITY
#UKADBiogas @adbioresources
CHAIR:
DR HUGH BULSON, ORA
PANEL:
BRITT NILSSON, KEMIRA KEMI AB
JØRGEN FINK, XERGI
DR THOMAS FRITZ, SCHAUMANN BIOENERGY
DR STEPHEN TEMPLE, JF TEMPLE & SON

2. Kemira Biogas Program
Kick-dose of trace elements – a first
aid at digester instability
Britt Nilsson Sr Application Specialist
Kemira Kemi AB, Sweden
britt.nilsson@kemira.com

3. Kemira Biogas Program
1-2 JulyBiogas Program | UK AD & Biogas 2015 | Britt Nilsson 3
Substrate pre-treatment
Odor control
Foam control
Biogas Boosting
Digester optimization
• Kick-dose of BDP
• Continuous dosing of BDP
Digestate treatment
Dewatering & reject
treatment
Scale control
Foam control
Nitrogen treatment
Stripping
Scale control
Foam control

4. Kemira BDP product concept
• BDP products are a concept to improve
digestion performance based on the
combination of iron, acid and trace elements
• The technology is patented by Tekniska Verken
in Linköping, Sweden and licensed to Kemira
1-2 July 4Biogas Program | UK AD & Biogas 2015 | Britt Nilsson

5. Case study: Digester recovery
Mesophilic
Substrate Crops, maize, sugar beet, animal feed residuals
Substrate load 60 000 ton/ year
Biogas production 7 000 000 Nm3/year
Energy production 45 GWh
Energy utilization Vehicle fuel
Challenge Urgent instability & digester collapse due to lack of nitrogen
5
160 ton /day Bio-fertilizerFeeding
tank
Digester
Biogas to gas upgrading unit
for vehicle fuel production
Target: Recover the digester process
1-2 July
Post digester
Biogas Program | UK AD & Biogas 2015 | Britt Nilsson

6. Case study: Digester recovery
Solution
• Immediate actions when instability occurred: stop
feeding, addition of alkali and urea
– alkalinity went up but VFA still very high >19000 mg/l
– propionic acid >4000 mg/l
• Addition of one kick-dose BDP start-up
– Within a week VFA went down from 19 000 to 4 000 mg/l
– After 2 weeks VFA was down at 400 mg/l
Effects of Kemira treatment:
+ Addition of essential trace elements enables production of
enzyme and co-enzyme needed for degradation of
intermediate fatty acids
+ The digester performance was recovered within 2 weeks
6
Kick-dose of BDP start-up gives immediate
effect in digesters with urgent instability
1-2 July
BDP kick-dose
Biogas Program | UK AD & Biogas 2015 | Britt Nilsson

7. Take away
1-2 JulyBiogas Program | UK AD & Biogas 2015 | Britt Nilsson 7
BDP kick dose to household waste, maize silage and
manure based systems give the following effects:
• One time kick-dose of BDP recover overloaded digesters
• Stabilizes digester performance
• Recover biogas production
• Substrate loading can be restarted within a shorter time

9. OPERATIONAL PERFORMANCE –
ADDITIVES AND PLANT STABILITY
#UKADBiogas @adbioresources
CHAIR:
DR HUGH BULSON, ORA
PANEL:
BRITT NILSSON, KEMIRA KEMI AB
JØRGEN FINK, XERGI
DR THOMAS FRITZ, SCHAUMANN BIOENERGY
DR STEPHEN TEMPLE, JF TEMPLE & SON