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Digester operation and making the most of the digestate

Date TBC, 2019, Wakefield

There are now over 600 Anaerobic Digestion plants in the UK processing a range of feedstocks, from sewage sludge to crops to food waste to liquid effluent produced from manufacturing.  Operators and managers are faced with the challenges of increasing energy production whilst minimising the costs associated with digestate disposal/recycling.  The supporting assets around the digester are vitally important in meeting these challenges.

This course provides operators, managers, designers and engineers with real life examples of digestion of different materials, successes and failures.

Over the past decade our attendees have told us that they value this course because:

  • It is face-to-face learning with knowledgeable industry experts who are passionate about their subject
  • Course delivery is energetic and engaging
  • Worked examples provide attendees with the tools to make changes to their site
  • The trainers are available for questions on the day and afterwards
  • Presenters take care and attention in ensuring that the level is pitched correctly for the audience

Separate courses are available for specific topics in specific sectors – please contact

Day 1

The different phases of AD & key terms

An introduction to anaerobic digestion (AD) which covers the key biochemical pathways to methane production as well as concepts of reactor design, configuration and operation.

Digester design and biogas handling

Different digester configurations, feeding approaches, and gas management options.  This module covers continuous, semi-continuous, batch, plug-flow, up-flow anaerobic sludge blanket (UASB) and continuous stirred tank reactor (CSTR) configurations – together with gas quality and handling, CHP and has upgrading.


This module introduces the concept of hazard analysis and critical control points (HACCP) planning, shows how it is used in sludge and digestate quality management – and how it influences plant layout, design and equipment selection. Management.

Metrics for digester operation

Following the introductions to AD and digester design, this module expands on key operational metrics – why they are important and how that should be measured.  Organic loading rate, hydraulic retention time, volatile solids’ destruction, volatile fatty acids and alkalinity will all be explored.

Common operational problems & solutions

AD has been used for processing sewage sludges for well over a century, but this doesn’t mean that there are never problems.  More recent diversification in digester feedstocks (such as food waste and silage) means that more things can go wrong, as digester configuration suited to one feedstock are misapplied to others.  Foaming, mixer fouling, tank failure, ammonia inhibition, grit and other common problems are considered in this module.

Day 2

Overview: biosolids and digestates

Having considered digester design and operation on Day 1, the second day focusses more on the back end of the process, beginning with an introduction to different types of digestate / biosolids – their benefits, regulation and key issues.


This module takes a closer look at regulations and quality assurance – starting with the customer, and delivering fit-for-purpose material that meets their expectations.  Concepts of sludge, waste and product will be considered, together with the Biosolids Assurance Scheme (BAS) and Biofertiliser Certification Scheme – which includes PAS110.

Maximising biogas production and how this influences digestate dewaterability

De-watering is a key element of sludge management, but is not without challenges.  This module covers the principles of de-watering and importance of polymer selection before examining why there are often differences between expected and actual performance.  The impacts of liquor or digestate return and the relationship between feedstock and dewaterability are also explored.

Agricultural use of biosolids and digestate

In the UK, most biosolids and digestate are applied to agricultural land, but this process may be managed by a third party, disconnecting the producer from the end user.  This module provides an insight into nutrient planning and the regulatory context within which farmers have to operate – highlighting the importance of delivering a joined-up service to maximise digestate value.

Other options for digestate

While previous modules highlight the importance of the agricultural market, this is by no means the only option.  Sports turf, land restoration and horticulture are considered here, alongside other approaches that extract nutrients from digestates – set within the context of cost, value and regulation.

Open discussion

This training package covers a lot of ground in two days, but is paced to give time for group and one-to-one discussions.

Who should attend:

  1. Digester plant operators from water and organic waste digestion sites looking to optimize their plant, maximize gate fees, throughput and revenue from biogas.
  2. Plant managers seeking to minimize the costs of digestate recycling
  3. Investment teams evaluating the long term financial model for a site and future options to dewater digestate economically and produce high value products.
  4. Plant designers
  5. Farm managers and agronomists seeking to unlock the value of digestate


Trainer profiles:

Matthew Smyth, Associate Technical DirectorMatt Smyth smiley portrait crop

See Matt’s details below

M Smyth Digester training profile



Dr David Tompkins, Bioresources Development ManagerDavid Tompkins new pic

See David’s details below 

D Tompkins Digester training profile.


Dr Maryam Kabir, Senior Anaerobic Digestion Specialist  

See Maryam’s details below

Dr- Maryam Kabir- Digester-training-profile



ADDRESS:  9 Appleton Court, Calder Park, Wakefield, WF2 7AR

For more details please see the leaflet Aqua Enviro Events Suite Travel Information that you can download above on the left hand side.

TIMES:  Training will begin at 9.30 am with tea and coffee available from 9.00 am.  There will be two tea breaks and a break for lunch (which is provided), the day finishes around 5.00 pm or a little before.

Multiple Booking Discount:  Multiple booking discounts are applied on a sliding scale as to the number of delegates booked:

  • 2+ delegates would receive a 10% discount (£576 per head for 2-days)
  • 5+ delegates would receive a 15% discount (£544 per head for 2-days)
  • 10+ delegates would receive a 20% discount (£512 per head for 2-days)

If  you would like to make a bulk booking please email Clare Hunter ( with the following details:

  1. Names, job titles and email addresses of all delegates
  2. Number of days each delegate would like to register for
  3. Total amount payable
  4. PO number and invoicing details


Dates for the training will be confirmed shortly. If you would like to register your interest or be added to our mailing list please email
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