Adding Value to Ash and Digestate (AVAnD):
Alfonso Lag Brotons, Rachel Marshall and Kirk T. Semple at Lancaster University
Ben Herbert and Lois Hurst at Stopford Energy and Environment
From the Glasshouse to the Field, Technical
Challenges and Commercial Opportunities
RESOURCE RECOVERY FROM WASTE ANNUAL
CONFERENCE 2017
Creating value from wastes in the bioeconomy
(Specialist Sessions and Discussions)
22 OF November 2017, Cloth Hall Court, Leeds
Resource Recovery from
Waste (RRfW)
https://rrfw.org.uk/
1- The AVAnD project
Overarching project aim:
Identification of a novel
nutrient-recycling pathway
to maximise soil quality and
crop productivity utilising
waste streams derived from
bioenergy production.
Work Package 1 Product formulation
1- AVAnD project overview
Work Package 2 Glasshouse trials
Work Package 3 Field trials
Work Package 4 Legislative requirementsProject end
Jan. 2018
Project start
Jan. 2015
Oct. 2015
Nov. 2016
ITERATIVE PROCESS
Throughout project
Characterisation of selected ash/digestate
and selection of blends for WP2
Assessment of ash, digestate & blend
impact on soil quality and crop growth
As for WP2, but with most promising
blends. Additionally, further ecosystems
impacts considered (i.e. GHG emissions).
Gathering evidences to permit application
to land/achieve product status
(e.g. “End of Waste”submission)
2- Policy background related to
AVAnD Fertilisers regulation (current) • Types-based categories
• Safe (no adverse effects)
• Effective (plant nutrition)
• Methodology available
• Specific requirements (e.g.
min./max. content
nutrients)
• Impairs circular economy (constraints innovative fert.)
• Lack of max. pollutant content
(e.g. heavy metals)
• Deters innovation (complex & length procedures)
• Non-mutual recognition
Source: Strubias kick off meeting
6/7 July 2016. Vicent Delvaux.
DG Grow. European commision
2- Policy background related to
AVAnD Fertilisers regulation (proposed)
Source: Strubias kick off meeting
6/7 July 2016. Vicent Delvaux.
DG Grow. European commision
AIMS To incentivize large scale fertilizer production from domestic sources, transforming waste
into nutrients for crops
To introduce harmonized Cd limits for P2O5 fertilisers
MAIN TRAITS Specific harmonized requirements on
Quality (e.g. min. content of organic matter)
Safety (limits for pollutants)
Labelling
CE marking
Introduction of recovery rules for biowaste
Potential for amendment (Annex I to IV)
Still not
adopted!!
Briefing EU legislation in progress – CE marked fertilising products. Didier Bourguignon. European Parlamentary research service
2- Policy background related to
AVAnD Fertilisers regulation (proposed)
2- Policy background related to
AVAnD Waste regulation (proposed)
Source: Strubias kick off meeting
6/7 July 2016. Vicent Delvaux.
DG Grow. European commision
Targets:
• Compost+digestate (EU level) – Materials Recycling (No energy recovery)
• Digestate (National level, UK) – Use in agriculture, forestry and
land restoration
2- Policy background related to
AVAnD End of Waste (EoW)
Source: End-of-waste criteria for biodegradable waste subjected to biological treatment (compost &
digestate): Technical proposals. Hans Saveyn & Peter Eder. EUR 26425 – Joint Research Centre –
Institute for Prospective Technological Studies. ISSN 1831-9424 (online)
Beneficial properties (for target)
Does not pose risk to environment
2- Policy background related to
AVAnD Nutrient Recovery Rules
Source: Strubias kick off meeting 6/7 July 2016. Vicent Delvaux. DG Grow. European commision
No specific regulation for wood ash use as material for fertiling products manufacture in
place.
Targets on Nutrient Recovery Rules for fertilisers production at EU (STRUBIAS draft)
and national (UK, Poultry Litter Ash Quality Protocol).
2- Policy background related to
AVAnD Nutrient Recovery Rules / EoW
Waste streams characterisation
o Waste streams screened down (2/6 selected)
o Whole digestate/ash fraction (no pre-
processing)
Blending
o Targeted 3:1 (total N:P ratios), resulting in
greater digestate proportion (liquid)
o Short mixing period before application
(consistent end point)
Dewaterability and nutrient fractionation
o Effect of ash addition done with AquaEnviro
o Optimum Polymer Dose approach –
Economically inviable (Polymer cost Vs
nutrients value)
Differential partition of nutrients (P, N
& K) in fibre and liqueour
3- AVAnD findings/ challenges/
opportunities Formulation
Stability !!!o Nitrogen loss enhanced by ash
Opportunity?
Ash added to enhance pathogen reduction and/or nitrogen loss in order to trap it later on?
Ash sterilizing effecto Ongoing research (JHI)
o Pathogen reduction due to ash
addition
Glasshouse experimental conditions
Wheat grown 6 weeks
2 soil types (Exp A – neutral loam soil;
Exp B – acid sandy)
Planted/Unplanted
Performance as good as conventional
inorganic fertilisers
Exp A – Nutritional effect
Exp B – Liming effect
Further variables assessed
Nutrient uptake
WUE
Soil fertility
Other experiments
Soil biota
C-cycling
3- AVAnD findings/ challenges/
opportunities Glasshouse trials
Field experimental conditions
Wheat (Nov16 – July 17)
Neutral loam soil (Exp A)
Well irrigated
Performance as good as
conventional inorganic fertilisers
Further variables assessed
Nutrient uptake
Microbial activity and community
GHG emissions
Plant nutrient availability
(cationic/anionic passive probes)
Currently growing ryegrass as 2nd
growing cycle.
3- AVAnD findings/ challenges/
opportunities Field trials (mesocosms)
Ash commercial Value
1) ASH/DIGESTATE blends (waste + product/waste)
Resulting blend = waste
Waste regulation applies
End use
Fertiliser - No specific EoW criteria = additional efforts/tools required
Soil amendment – waste framework (e.g. R10 Land treatment resulting in benefit
to agriculture or ecological improvement)
2) ASH/DIGESTATE blends (product+product)
Resulting blend = (likely) product
Requirements = compliance with EoW /Recovery Rules
No waste regulation route (EU fertilizer regulation)
3) ASH, DIGESTATE (product/waste + product/waste)
Target: one retained as product other enhances quality (e.g. ash / AD pathogens).
Value enhancement (e.g. “Nutritional Value”)
Additional implication (e.g. new waste generated)
3- AVAnD findings/ challenges/
opportunities Potential scenarios
4- Future directions on the AVAnD scope
Further research lines dependent on:
Regulatory framework (Still “in the air”!)
Scale (industrial or small)
End use (e.g. production of fertilisers; soil improver, liming agent)
Management scenarios (e.g. application to land, improvement of digestate
quality)
Essential to achieve stability and advisable to find ways to dewater the blends
Concerning fertilizer production, valuable to consider legislations/regulations
(EoW, revised fertilizer regulation) (once adopted?) for target composition
(nutrients/pollutants).
NEW RELATED RESEARCH• Formulation development - PhD (October 2016 – 2019)
• RECIRCULATE – GCRF: Growing research capability to meet the challenges
faced by developing countries (October 2017-2021)
• Bioenergy residues in sub-Saharan Africa - NERC IOF (November 2017 - 2019)
• AVAnD II – Innovate UK/BBSRC (January 18 – May 19)
Prof. Kirk T. Semple Prof. Nick OstleDr. Farid Aiouache
Dr. Ian Dodd Dr. Ben Surridge Prof. John
Quinton
Dr. Rachel Marshall
Dr. Alfonso José
Lag Brotons
Dr. Ben Herbert Lois Hurst
Dr. Marc Stutter Dr. Samia Richards
Dr. David Thompkins Andy Burguess
1- The AVAnD project Team
THANK YOU!!
QUESTIONS?