Institution news
In June 2011, the Institution of Mechanical Engineers proposed that members of its Greater London Region Young Members Group would be involved in an outreach project. After some research, the group chose to work with Project Moz, a registered charity with experience in carrying out community projects in Mozambique.
Having overcome many technical obstacles, the team has now completed a concept design and carried out a 1:50 scale test on the innovative solution.
Project Manager Phil Ebner said: “We are far closer to providing an irrigation system which will allow the community to farm crops on their land in an efficient and sustainable manner.”
During development of the proposal for the system, the first step towards validating research into the best type of irrigation system was to test the soil and water in the area. The team found that the salinity level of the water basin below the proposed site of the irrigation system was equivalent to that of seawater: far too high for the purposes of farming. The team had to abandon all previous design work and start from scratch. A second range of options was analysed, taking into account desalination techniques that required no energy input other than solar.
The concept of the final proposal is for a seawater greenhouse scenario. This is based around saline water passing vertically by gravity through a filter pad which covers one entire surface of the greenhouse. The hot, dry air will pass across this wet salty ‘pad’ causing the water to evaporate and the air to increase in humidity. This results in a cooler air on the internal side of the filter. The leftover salt remains in the voids of the filter, increasing its lifespan to five or 10 years, depending on initial salt contents.
From early on in the project, the team has consulted with professionals working in water filtration, for advice on desalination. Being aware that the system will eventually have to be managed and maintained by the farming association in the community was instrumental in deciding on a suitable option. More traditional options, without maintenance requirements – such as the use of a greenhouse and evaporation techniques – were looked upon favourably.
The benefit of the seawater greenhouse design is that it is inspired by the natural water cycle, which means that it is not energy intensive. Also, the humid conditions created by the greenhouse itself enable greater yields, and a better quality of crop, and relies on less water than traditional irrigation systems.
In October 2013, Operations Lead Damy Balogun presented the seawater greenhouse option to water professionals at the Institution’s Water and Energy seminar. The proposal was well received. Since then, the team has constructed a prototype which has been tested against a variety of conditions, similar to ambient conditions in Mozambique.
To recreate this environment, air flow, water flow and humidity were altered using simple heaters, steam and dehumidifiers. The temperature and humidity were measured using data loggers at either side of the replica cooling pads. The results of the tests were positive, giving the group a mandate to validate further the findings within the wider engineering community, and progress with detailed design and procurement. In the meantime, the group will install a rainwater harvesting system which will be constructed on an existing orphanage building in the community.
However, further investigation is required in order to assess whether this concept will work in reality. Project Moz Irrigation is calling for young volunteers to help with this prestigious project, taking part from now, to the proposed build date in early 2015.
Please contact
MozIrrigation@engineersvolunteer.org for more information.
Project Moz Irrigation Challenge
Project Moz Irrigation is running a competition to develop a small-scale solution to turn saline water to drinking water for less than £100. Entrants must be current or recently graduated students of an engineering degree. Further information on the competition and prize for the winning solution will be available soon at www.engineersvolunteer.org or, for more information, please email MozIrrigation@engineersvolunteer.org