A practical guide by Steve Last, CEng, MICE, MCWIM
Make better-informed anaerobic digestion decisions—before costly problems become built in
Anaerobic Digestion: A Practical Guide to Feedstocks, Biogas, Digestate and Successful AD Plants explains how the biology, equipment, inputs and outputs must work together for a viable AD project.
Assess feedstocks, contamination and biological risks more realistically.
Understand the main digester systems and the decisions that shape performance.
Plan for biogas use and digestate outlets as essential parts of the project.
61-page illustrated PDF · approximately 20,000 words · immediate delivery through Gumroad
61 pagesClear, focused guidance
8 diagramsOriginal explanatory visuals
Practical toolsTables, checklists and worksheets
25+ yearsExperience behind the guide
AD is a system, not simply a tank
A promising feedstock and a proven digester do not automatically make a successful plant
Anaerobic digestion projects bring together biology, waste handling, mechanical equipment, energy production, regulation and nutrient management. A weakness in any one part can affect everything downstream.
An attractive gate fee can be wiped out by contamination or inhibition. High theoretical gas yield means little if the material cannot be handled reliably. Valuable digestate nutrients can become a liability when there is no secure, lawful outlet.
This guide helps you examine those connections before accepting assumptions, selecting equipment or committing money.
“Its success depends on matching the feedstock, process design, gas use and digestate outlet very specifically to the site and the available organic waste supply.”
What the guide covers
Follow the complete journey from incoming organic material to useful outputs
The guide is structured to help you see how each decision influences plant reliability, energy recovery and digestate management.
01
Feedstocks and acceptance
Evaluate composition, contamination, pumpability, ammonia risk, variability and security of supply—not gas yield alone.
02
The biological process
Understand the linked stages of digestion and why stable feeding, temperature and loading matter to the microbial community.
03
Digester selection
Compare important reactor distinctions and relate them to solids content, feed characteristics, retention and treatment objectives.
04
Mixing and pumping
Recognise why poor mixing, floating crusts, viscosity and unsuitable handling equipment can undermine otherwise sound biology.
05
Biogas and biomethane
Follow raw biogas through cleaning and use, including CHP, upgrading, methane control and the role of biogenic carbon dioxide.
06
Digestate and outlets
Treat digestate quality, storage, nutrients, contamination and end use as fundamental project requirements—not afterthoughts.
Look inside
Practical reference material you can return to
This is more than a continuous block of text. Diagrams, tables and checklists make the important relationships easier to review and discuss.
Appendices and practical reference content A practical roadmap for assessing an AD project Troubleshooting table and checklist examples
Use it to ask better questions
Strengthen the decisions made before and during plant development
The guide will help you recognise where a proposal needs better evidence, closer investigation or specialist advice.
Question optimistic feedstock and gas-yield assumptions.
Identify contamination and pre-treatment requirements.
Understand why feedstock and reactor selection belong together.
Recognise biological inhibition and instability risks.
Consider mixing, pumping and maintainability early.
Compare CHP and biomethane in the proper context.
Plan for methane leakage and gas safety.
Test whether every tonne of digestate has a credible outlet.
Review the whole system instead of isolated equipment.
Know when a feedstock or project should be refused.
Who this is for
Accessible to newcomers, useful to experienced decision-makers
This guide will be particularly useful to:
AD plant owners, operators and prospective developers
Farmers and waste producers considering digestion
Waste, wastewater and environmental professionals
Engineers, consultants, planners and investors
Students and researchers seeking an applied overview
Anyone reviewing an AD proposal or business case
What the guide does—and does not—do
It provides a clear, practical framework for understanding and evaluating AD projects. It is not a substitute for feedstock testing, site-specific engineering, regulatory advice, process guarantees or a detailed feasibility study.
Its purpose is to help you approach those specialist stages better informed and less likely to overlook a critical dependency.
Steve Last CEng, MICE, MCWIM
Over 25 years’ experience across anaerobic digestion, biogas, landfill gas and waste management.
Steve Last is a Chartered Engineer whose career has included waste engineering, landfill gas and anaerobic digestion projects. His experience has repeatedly reinforced one lesson: successful AD depends on how well the complete system fits its feedstock, site and intended outputs.
The guide combines accessible technical explanation with practical cautions about difficult feedstocks, mixing, equipment selection, gas utilisation and digestate planning.
Your reference guide
Keep the complete AD system in view
Use the guide while learning about the industry, reviewing an opportunity, preparing questions for suppliers or checking whether a proposal has addressed the essentials.
Clickable contents and source links make it easy to move between sections and continue your research.
Questions before purchasing
Frequently asked questions
Is the guide suitable for someone new to anaerobic digestion?
Yes. It explains the essential biology, plant components, feedstocks and outputs in accessible language. More experienced readers can use the tables, cautions and checklists as a practical reference.
Is it limited to the UK?
No. The scientific and engineering principles apply internationally. The guide uses British English and includes some UK context, but readers elsewhere can apply its decision-making framework while checking their own laws and standards.
Is this a detailed plant design manual?
No. It will help you understand plant selection and recognise important design dependencies, but it does not replace site-specific engineering, laboratory tests, safety assessments, permits or supplier guarantees.
What format will I receive?
You will receive the finished 61-page guide as a PDF suitable for reading on a computer or tablet and for personal reference printing.
How will the guide be delivered?
Payment and delivery are handled securely by Gumroad. After completing checkout, you will receive access to the downloadable PDF.
Can the guide tell me whether a particular AD project will succeed?
No publication can guarantee that. The guide helps you test assumptions and recognise the evidence a credible assessment needs. A real project still requires representative feedstock data, site investigation, commercial checks, regulatory review and competent professional advice.
Download the complete guide
A better AD decision starts with understanding the whole system
Get the practical framework for assessing feedstocks, plant selection, biogas, digestate and the dependencies that determine whether an anaerobic digestion project works in practice. £27 Get Instant Access
One-time payment · secure Gumroad checkout · immediate PDF delivery
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