Welcome to The Society of Environmental Engineers
Young Environmental Engineer of the Year Award 2012
Jamie Radford – Mott MacDonald Ltd
Jamie graduated with a First Class MEng in Civil & Environmental Engineering from the University of Cambridge in 2011. He joined the Water Division of Mott MacDonald as a Graduate Civil Engineer and has had varied experiences ranging from designing erosion protection works for irrigation canals in Afghanistan, to helping a major UK water company prepare for the 2014 Periodic Review. Jamie is currently working on developing an improved understanding of the mechanics of faecal sludge, through ongoing work at Mott MacDonald and the University of Cambridge, and recently presented at the International Faecal Sludge Management Conference FSM2 in Durban, South Africa. The focus of the work is to support the development of improved sanitation services and latrine emptying technologies, specifically for use in high density urban areas - something that will become increasingly important as the world's slum population is forecast to grow to almost 3 billion people by 2050.
Development of a device to physically characterise pit latrine sludge
A truly global problem
There are an estimated 2.5 billion people in the world without access to improved sanitation (WHO & UNICEF 2012) which contributes to an estimated 840,000 child deaths from diarrhoeal disease every year (UNICEF 2012). Unfortunately the situation is set to get worse, with dramatic urbanisation coupled to rapid population growth in developing countries producing an estimated two billion additional slum-dwellers by 2050 (UN-Habitat 2012). A glimpse into the future can been seen in places like Kibera, Nairobi, where housing is so dense that there is no space to dig new latrines. As a result residents resort to open defecation or 'flying toilets', where waste is wrapped in plastic or newspaper and thrown onto their neighbour's roof. When pits are emptied it is typically done manually, with someone paid as little as $20 to be immersed waist-deep in faecal sludge for six hours at a time. Manual pit emptiers are at risk of being crushed to death if the pit collapses, as well as being exposed to infectious diseases from handling sludge, and they often turn to alcohol to overcome the disgusting nature of their work (Sugden 2012).
This situation is clearly both unsustainable and unacceptable. While you are reading this paper approximately 15 children will die from diarrhoeal disease caused by poor sanitation. Overflowing latrines and open defecation pollute water sources that are an important resource to downstream users and the widespread environmental contamination caused by illegal dumping of untreated pit latrine sludge destroys natural ecosystems. Abandoning a full pit and building a new latrine, where there is space to do so, is ten to fifteen times more expensive than emptying, but despite this there are very few examples of safe and sustainable pit-emptying businesses serving the urban poor.
Overflowing latrines and manual emptiers dumping sludge into the environment
An enabling innovation
There is evidently a real need to develop improved pit-emptying services for urban areas. In recent years there have been widespread efforts to design low-cost pit emptying technologies that are affordable to entrepreneurs living in urban informal settlements. However this work is constrained by a lack of data on the physical properties of latrine sludge and the absence of a test to benchmark the performance of different machines. Currently comparisons are made on the basis of subjective assessments of the machines' performances, making it difficult to identify the most promising innovations and focus development efforts and resources accordingly.
As part of my Masters project at the University of Cambridge I developed a framework for the physical characterisation of pit latrine sludge, using undrained shear strength and bulk density as the critical parameters controlling whether sludge can be removed from a latrine. Laboratory tests using synthetic sludge demonstrated that a mini-ball penetrometer (Kuo 2011), typically used in the offshore drilling industry to test very weak marine muds, could produce the necessary precision to characterise pit latrine sludge.
The insides of the mini-ball penetrometer and synthetic sludge simulant in the laboratory
The development challenge
Having demonstrated the proof-of-concept for a device to characterise pit latrine sludge, I was set the challenge of developing a simple and man-portable version of the device for testing latrines. To provide some context, the original laboratory equipment required a three phase high voltage power supply, used two computers, had a footprint greater than 25m2 and cost tens of thousands of pounds. A comparable commercially-available system for ground investigations (vane shear tester) was quoted at £20,000 with a shipping weight approaching half a tonne – certainly not man-portable!
The conceptual and detailed design required my multidisciplinary understanding of geotechnical, mechanical, electronic, structural and software engineering, with support from experts at Mott MacDonald and the University of Cambridge. The main design constraint was that access to the pit for testing was limited to a 100mm diameter squat hole. This controlled the size of ball that could be used and therefore the maximum diameter of testing shaft and the minimum sensitivity for force measurement. The relatively small ball and weak sludge strengths made the standard practice of strain-gauging the shaft directly above the ball impossible. Instead the ball penetrometer and shaft are suspended from a load cell inside the machine. This has the additional advantage that the electronics, which are expensive and irreplaceable in the field, do not enter the latrine – the test shaft simply consists of a jointed aluminium tube with a plastic ball on the end. This proved a particularly sound decision when one of the joints came unscrewed during initial testing and the ball was lost at the bottom of a septic tank!
Prototype field testing
A prototype Portable Penetrometer was manufactured and tested in Kampala, Uganda, during April 2012 in partnership with Water for People. Thirty pits were characterised over the course of two weeks, with a continuous strength profile recorded for the undisturbed sludge through the top 2.5m depth of each pit. The results demonstrate that pit latrine sludge is highly variable, both within and between pits and is significantly stronger than previously reported in the literature. The effect of extraneous matter in the pit such as rubbish or rocks can also be identified as sudden peaks in the strength profile. The value of producing continuous strength profiles was highlighted by the fact that the sludge observed at the surface of the pit is often not representative of the overall pit volume, as demonstrated in the figure below. The Portable Penetrometer can also be used to break down the physical structure of the sludge and test the strength of the material once remoulded, which is indicative of the sludge after removal from the pit. The ratio of the undisturbed and remoulded strengths, the sludge sensitivity, was found to be greater than three. This indicates that there is significant potential to increase the solids content and volume of sludge that can be pumped, by first 'fluidising' it within the pit so that it is the remoulded, not undisturbed, strength that has to be overcome during emptying. A comprehensive analysis of the data is currently being prepared for submission to a peerreviewed journal.
In addition to the data gathered, the time spent within the community helped to raise awareness of pit emptying and generate demand for the service. Since my visit Water for People have helped a local entrepreneur to develop a business plan for the mechanised emptying of pit latrines, and their customer base continues to grow rapidly after the first two months.
Laboratory calibration of the Portable Penetrometer and my audience for field testing
Future developments
The field trials identified a number of areas for further development of the Portable Penetrometer, while also demonstrating its ability to rapidly collect high quality data on pit latrine sludge. This will enable the quantitative evaluation of the performance of different pit emptying technologies as well as making it possible to monitor the performance of different latrines over time. This is vital for investigating the factors that affect pit longevity – something that is currently very poorly understood, as well as providing a tool for wide ranging scientific experiments on pit function, such as testing the effect of modifications to the latrine design on sludge strength and fill up rates. The Portable Penetrometer therefore has the potential to facilitate wide-ranging social, economic and environmental improvements in the universal provision of sanitation by providing the missing data that is currently preventing effective scientific investigation into improved sanitation systems.
Acknowledgements
Funding for the project was received from UN-Habitat, the London School of Hygiene and Tropical Medicine and the Mott MacDonald Water and Environment Corporate Social Responsibility Committee. The work would not have been possible without the invaluable advice received from Dr. Richard Fenner, Manus Coffey, Steven Sugden, Prof. Malcolm Bolton and Dr. Matthew Kuo.
References
UNICEF & World Health Organisation (WHO) 2012 Progress on drinking water and sanitation: 2012 update.
WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation, New York
United Nations Human Settlements Program (UN-Habitat) 2012 State of the World's Cities 2012/13: Prosperity of cities. UN-Habitat, Nairobi
United Nations Childrens Fund (UNICEF) 2012 Pneumonia and diarrhoea: Tackling the deadliest diseases for the world's poorest children. UNICEF, New York
Kuo, M.Y. 2011 Deep ocean clay crusts: behaviour and biological origin. Ph.D. University of Cambridge
Sugden, S. 2012 Reflections on Business models and technology designs for pit emptying services International
Conference on Faecal Sludge Management, Durban, South Africa 29-31 October 2012
Coasts, Marine Structures and Breakwaters 2013
The SEE is supporting the Institution of Civil Engineers (ICE) Coasts, Marines Structures and Breakwaters 2013, event taking place on 17-20 September 2013 in Edinburgh.
‘From sea to shore – meeting the challenges of the sea’ is the tenth in this highly-regarded series of specialist conferences. Known for offering the best international forum for the discussion of the latest development as well as informed debate – every event in the ‘Breakwaters’ series has ensured that advances in coastal engineering are appropriately highlighted.
The conference will showcase up to 150 technical papers over three days covering all aspects of coastal engineering. For a full list of topics and themes please see the attached call for papers flyer.
Download pdf copy here: Download Flyer
Engineering Ethics in Practice
The Engineering Council is circulating and promoting a new document from The Royal Academy of Engineering on “Engineering Ethics in Practice: a guide to engineers. This document contains practical guidance”. This document including case studies and discussions on ethical situations a professional engineer may encounter. Anybody who is contemplating registration as CEng or IEng should consider this document to be essential reading as knowledge of Engineering Ethics is one of the competences that will be tested at the Professional Review. For existing registered engineers the document is a well written and useful guide. Moreover, reading this document would contribute towards your continued Professional Development (CPD).
Download pdf copy here: Engineering_ethics_in_practice
Guidance on Sustainability
This document has been issued by the Engineering Council to help Engineers carry out their role in a broad sustainability context that encompasses social, ethical, environmental and economic challenges.
Download a pdf copy here: Guidance on Sustainability.pdf
Chartered Environmentalist
The Society is a Constituent Body (CB) of the Society for the Environment (SocEnv). This means that we are able to enrol suitably qualified Members of the Society as Chartered Environmentalists (CEnv).
The Society for the Environment (SocEnv) (www.socenv.org.uk) is the leading co-ordinating body in environmental matters and is a champion of a sustainable environment.
SocEnv was formed in 2000 and granted a Royal Charter in 2004. The qualification of CEnv is a high level professional qualification available to environmental practitioners. It demonstrates high standards of professional practice, knowledge, competence and engagement, and is recognised by employers as the test of professionalism in sustainable and environmental management. Chartered Environmentalists work in many sectors and are leading in managing environmental assets and they are playing an important part in the goal of a sustainable world.
The following link will take you to the Chartered Environmentalist Specification.
Please contact the SEE Secretariat for more details and application form, email: office@environmental.org.uk Tel: +44 (0)1763 271209.
"CEN WS10 Expert Group 8 Final Report"
"CEN Workshop 10 - European Handbook for Defence Procurement - Expert Group 17 Dependability & Safety final report."
SEE Sponsors events with IMechE
IMechE are holding a number of events in the next few months where SEE are co-sponsors. Dates for your diaries are:
PROJECT TO USE WASTE CHIP FAT IN ASPHALT COMMENDED BY ENGINEERING INDUSTRY
Young engineer Helen Bailey has won a prestigious industry award for her pioneering work which could reduce the carbon footprint of Britain’s road building industry using waste chip fat.
Technical Forum – Current Hot Topic
Laser Vibrometry – A Practical Application
Chartered Environmentalist
The Society is a Constituent Body (CB) of the Society for the Environment (SocEnv). This means that we shall can enrol suitably qualified Members of the Society as Chartered Environmentalists (CEnv).
The BLOODHOUND Project.
New World Land Speed Record Attempt - 1000 mph
CITNEXUS - DISCOUNTED SOFTWARE
The Society has entered into an arrangement with Citnexus to make available heavily discounted software to Society Members
