Fundamentals of Activated Sludge and Anaerobic Digestion for Engineers


1-day course

CPD Credit: 7 hours, C1

Course Aim

A number of key concepts underpin the design, operation and optimization of both activated sludge and anaerobic digestion plants.This course will explain these, how and why engineers choose different hydraulic retention times, loading rates, sludge age and more.

By understanding key terms, the value of conversations between engineers and the resulting outputs are enhanced.

Course Overview

The activated sludge process was invented in 1914 and has since become the preferred process around the world to meet tight, wastewater discharge consents for larger works.It is the main energy consumer on treatment sites, as such can be optimised to achieve compliance at least cost.

The quantity of wastewater sludge produced in Ireland is projected to increase by 80% by 2040 to ~96,000 tonnes of dry solids.Thickening, dewatering and anaerobic digestion help to reduce the volumes that need to be transported and the associated costs. Maximising energy recovery from anaerobic digestion is a priority for local authorities and water companies.

This course will provide attendees with a comprehensive understanding of the activated sludge and anaerobic digestion process including terms used to describe health and efficiency, key performance indicators and case studies to demonstrate where improvements can be made, and challenges overcome.

Course Objectives

After the course participants should be able to:

  • Understand how and why activated sludge/anaerobic digestion plants are sized
  • Appreciate the key metrics that are used to control plant operation
  • Understand common operational problems and solutions
  • Approximate the operational costs of treatment and the revenue potential of anaerobic digestion


Activated sludge design and operating fundamentals – sludge age, hydraulic retention time, carbonaceous, nitrogen and phosphorus removal.

Achieving compliance at least cost.

Anaerobic digestion key performance metrics – hydraulic retention time, organic loading rate, methane yield, energy production, VFA: alkalinity

Maximizing biogas (energy) production and throughput from anaerobic digestion

Common operational problems and their solutions

Who Should Attend?

This course is aimed at engineers with an interest in or new to wastewater treatment.The course will focus on the activated sludge process for meeting discharge consents to water courses and recovering energy from sludges to generate renewable energy through anaerobic digestion.

Trainer’s Profile

Matthew SmythBSc, MRes, MBA, MCIWEM CSci CWEM

Technical Director, Aqua Enviro

Matt has been in wastewater and sludge for twenty years and works with water companies, industry and waste producers to develop and implement solutions.In the late 1990’s he began his career working on pilot and full-scale Sequencing Batch Reactors, developing, then commissioning carbonaceous and nitrification control strategies, that have been widely adopted plants at in the UK and Ireland.He has subsequently worked closely with many anaerobic and advanced anaerobic digestion facilities treating wastewater and food waste materials, dewatering the digestate and handling the liquors produced.He presents and publishes regularly at industry recognized conferences including Aqua Enviro’s European Biosolids & Organics and European Wastewater Management Conferences.He is a member of the CIWEM Wastewater Management Panel and the ADBA Training, Safety & Environment Working Group.Matt has delivered over 2000 training days on these topics (1 training day is when 1 person attends 1 course for 1 day).


Engineers Ireland supports the Sustainable Development Goals. This event contributes to Engineers Ireland's Sustainability Framework.

Please contact the Team for further information on scheduled course dates and In-Company options. You can reach us by phone: 01 665 1305 or email