The WHO guidelines state that there must me not a single bacteria present in 100ml of water for it to be safe to drink - this is like finding and removing a garden pea from somewhere in London King's Cross Station. To be able to find and identify that single bacterium, we first need to remove other particulars in the water.
Like other current water quality systems on the market, we do this by using the conventional method of using a membrane to filter the water to isolate the bacteria, and adding nutrient media to an absorbent pad to allow bacteria to grow. Current methods (which are large and complex) do this manually, and the sample needs to be processed in the lab to be completed effectively.
Our system is automated, making it robust by minimising the propensity of contamination by human error. We use a specialised disposable cartridge which shrinks the process and removes the need for a laboratory (tests can be completed in the field) eliminating complex sterilisation steps and the use of dangerous chemicals. We use vacuum filtration to make the process simple and fast.
Our system is low-cost, light, easily transportable, and can be easily operated making it ideal for use in low and middle-income countries. Users do not need to be highly trained to use the system as the automation means that test results are guaranteed to be correct.
Once the sample has been collected in the cartridge it is incubated in our portable incubator to allow for bacterial growth. A microscope embedded within the system uses a Raspberry Pi and image recognition software to identify early bacterial growth. Automated counting and identification removes dependent skill sets of personnel making the test faster and more effective than current systems which use personnel to identify bacterial colonies by eye.
The system then visualises the results in a way that can be read by anyone, independent of skill set. Results are collected and stored internally irradiating dependancy on internet or connectivity. Once the system is in range of connection, data can be disseminated to a central hub for effective intervention.
The WaterScope system was designed and developed with the end user. Through our partnership with Oxfam, and guidance from their field workers in Tanzania, we iterated the design in a participatory feedback loop. With guidance from them, and colleagues in India, we have designed a system that is robust, effective and low-cost.