Optimising Anaerobic Digesters: Sewage Sludge 5/7/22

5 July 2022, VIRTUAL


Over 80% of sewage sludge produced in the UK is treated by anaerobic digesters. The biogas produced is a renewable energy source and can be used to generate electricity and heat or converted into biomethane for grid injection, whilst the biosolids produced are generally dewatered and applied to land.

Operators and managers are faced with the challenges of increasing energy production whilst minimising the costs associated with digestate disposal/recycling at anaerobic digester plants.  There are many factors that influence the financial balance.  With the advent of 2020 and a competitive bioresources market delivering upon innovation and efficiency, now more than ever it is vital to understand revenue and cost drivers at the site and business levels.

This anaerobic digester training course is beneficial for operators, optimisers, process scientists and managers in the wastewater/sewage sludge sector.  Also academics and post-grad students aiming to get practical insight.


Each one tonne of dry solids produced from wastewater contains 4-7 MWh of energy, the quantity recovered is a function of the digestion process, asset condition and quality of feedstock.  The digestate produced is both a cost to handle and an opportunity to recover nutrients and produce a compliant product.

This anaerobic digester training course is designed to help attendees understand and act upon the factors that influence biogas production, sludge dewaterability, biosolids compliance, cost and revenue generation.

Learning is delivered through a combination of lectures, case studies and worked examples.


  • The different phases of AD & key terms
  • Advanced anaerobic digestion – thermal and biological hydrolysis
  • Metrics for digester operation including VFA: alkalinity, hydraulic retention time, organic loading rate and rate of volatile solids destruction
  • Commissioning digesters and takeover testing
  • Common operational problems & solutions including foaming and inhibition
  • Dewatering digestate, chemical dosing techniques and technologies
  • Liquor Treatment – understanding the nitrogen cycle, technologies in the marketplace and optimisation
  • The Biosolids Assurance Scheme 

Who should attend?

This course covers the fundamentals of anaerobic digestion whilst drawing upon an array of practical case studies.  As such the course has wide appeal being highly relevant to operational teams, process scientists and managers looking to upskill and optimise, technology providers seeking to understand where products fit in the market, researchers and innovators wishing to understand the latest challenges facing the water industry and anyone interested in understanding the UK market and investment drivers.

Why invest in Anaerobic Digester Training?

  • Gain a full understanding of the different phases of anaerobic digestion and the tests employed to measure efficiency and stability in this tailored anaerobic digester training course.
  • Energy generation is a function of metric including hydraulic retention time and organic loading rate, but also a whole host of other factors including calorific value and type of feed, digester mixing, ammonium levels, temperature, volatile fatty acid and alkalinity levels, foam generation. You will understand these individually, but also how different factors are interrelated.
  • Understand why and when anaerobic digesters foam, the causes and the solutions.
  • Implications of digestate and liquor quality upon dewatering and liquor treatment processes.
  • Experience real world examples and case studies that cover a multitude of troubleshooting and optimisation experiences gained over 20+ years
  • Enhance the value of your conversations and meetings with colleagues across the business by using common language and terminology to define and agree solutions


This course will be delivered ONLINE from 9:30 am-16:30 pm (also available on 9th March, please book that course here)


£345 plus VAT for 1-person, (includes slides presented).  15% discount on total price if all three courses booked at the same time: Activated Sludge & Wastewater courses. NB: the fee is for 1 attendee (no one in the background peeking please).  Please get in touch to discuss discounts if you would like more than one place

Optional extras

  •  A 1-2-1 follow up with trainer Matthew Smyth to reinforce learning at £205 plus VAT (2 hours).
  • A 1-day course, tailored to your requirements, is a popular choice by water companies or contractors to have delivered on their sites to operational staff.  Please contact if you’d like to discuss this option.

Ready for the next level of training?

This training dovetails with our Wastewater Treatment and Activated Sludge courses.  To understand, evaluate and optimise any site we must be able to interrogate individual plant items and how the performance of each influences adjacent process units and the performance as a whole.  Wastewater treatment is quite literally a case of the toe bone being connected to the foot bone, to the heel bone, ankle, leg, knee, thigh, hip and everything else.

If you would like a 1-2-1 follow up with Matt to hone your learnings and reach the next level, this can also be ordered here.

Case studies and worked examples at the core of the training

Irrespective of whether you are working on a domestic wastewater treatment site or industrial effluent treatment plant, this joined up approach is valid.  Here are some case study examples:

  • Innovative approach to plant optimisation – a whole works approach
    • Water company seeking to stretch energy generation on sites to as high as possible, whilst achieving throughout targets.
    • Sludges can be ranked in terms energy content and energy availability, whilst few sites do this you will understand the importance and techniques to maximise sludge quality from an energy perspective.
    • Site data and sampling studies combined to produce calibrated Biowin models to demonstrate potential energy and throughout gains. The model can be used to highlights the benefits / opex associated with changes in plant operation at primary and secondary treatment plants, not just AD.
    • Model used to justify spend to save schemes including:
      • Reconfiguring pipework and storage tanks to improve sludge quality
      • Capturing energy embedded in liquors and reusing in cake rewetting process
      • Re-routing of specific imports to given sites faced with challenges of meeting ammonia consents
      • Greater focus on return liquor management

Scaling across multiple sites, driven by legislative change (Water Framework Directive)

        • Pipework, heat exchangers and digesters often suffer from scalant deposits.
        • Investigative analysis can be used to identify the components which are typically comprised of calcite, struvite, vivianite
        • This is a growing challenge on sites that either have new/tightened consents to discharge for phosphorus, or are receiving imports from sites that remove P.
        • Managing phosphorus and scalants is a huge challenge and one that is not easily resolved, but which can be understood. Investigations need to be site specific as it depends on the impact, be it increased maintenance, reduced digester throughout or a discharge consent challenge.
        • The biggest challenge is at sites employing biological phosphorus removal and at the same time processing iron rich (Chemical P) sludge imports. These P-rich sludges will release phosphorus in the digesters, in turn this adversely affects the dewatered cake dry solids that can be achieved, whilst bringing huge scaling challenges.
        • Investigations in this area are site specific, but you will leave armed with the tools to understand this complex, interrelated challenge, that is here to stay and with references to draw upon.

Do you have a challenge with your Anaerobic Digester right now?

Get in touch to see how we can help and embed learning in the process.  We have vastly experienced teams with in-depth knowledge that will cover all aspects of your challenge.


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Cost per person
£345 (ex. 20% VAT)

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