Why am I Building a Turbidity Sensor?


Why am I Building a Turbidity Sensor?

I just spent an entire month writing a grant proposal for a PhD project to develop my very own open-sourced, affordable, turbidity sensor.

Current available sensors cost around 10,000-100,000EUR. Monitoring turbidity in a river can give you information on the total suspended sediment in the water, but why else is this parameter important? In the following video, I go through and answer the following important questions:

What is turbidity?

Basically, it’s the cloudiness of a fluid caused by the presence of a large number of individual particles (usually naked to the human eye). These particles can be of various sizes. Big particles will settle to the bottom while small particles wont (because water is continuously agitating them).

Why is knowing the turbidity of freshwater important?

In 2014, WHO recommended an NTU < 1 for drinking water prior to disinfection. This low turbidity range is important because a high level increases the risk of gastrointestinal disease. This is especially important for immunocompromised people because viruses and bacteria attach themselves to suspended solids and the solids act as shields against chlorine disinfection and UV sterilization.

During natural disaster situations, the first thing people need is water. So you can see why this measurement is important.

Depending on the ecosystem, different turbidity levels are needed because different species thrive in different waters (ex. some waters need high turbidity levels to protect baby fish from predators which high turbidity levels in other water bodies are bad because it prevents light from reaching the bottom of the lake and inhibits growth of submerged aquatic plants and therefore, the species that depend on them).

So it’s not the amount of turbidity but the change in turbidity that is important for ecosystems.

What are the causes of varying turbidity?


These are small photosynthesizing organisms that inhabit the upper sunlit layer of almost all oceans and large freshwater bodies. They take dissolved CO2 from water and absorb energy from the sun via photosynthesis and then they release O2 into water and create organic compounds which sustain the food web.

It’s estimated that 50-85% of the world’s oxygen is produced via phytoplankton photosynthesis.

by human activity

Construction, mining, agriculture… These sediments enter the water during a rain storm. Also, erosion of pavement, such as roads, bridged, parking lots, in urban areas. Again, storm water transports this sediment into water.

Why if this a problem?

Because we go into different countries and construct dams and mines for our own energy benefits and this sediment trickles into the river and kills fish, leaving locals with dirty water and nothing to eat.

Thanks for making it this far, watch the video below to hear me explain this problem, again.