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?