Make With Mouser IoT Design Contest

Title: Low-cost IoT-based Water Pollution Monitoring Device: Wireless Water Monitoring Station (WWMS)

Water pollution has become a serious problem worldwide and impacts negatively on the sustainability of drinking water resources. The degradation of water quality due to water pollution has also caused serious financial losses in the fish farming sector involving the cage system. Most water contamination incidents are due to the lack of policing of industry and business activities by the local authority due to the lack of water quality monitoring facility. To date, most of the developing countries do not have the proper water quality monitoring system for the lake and river to govern in water pollution due to the high operational cost and geographical issues. water quality monitoring system. For example, illegal dumping of chemical wastes into rivers is also hardly detected by the authorities especially at night time. In most cases, water pollution is only detected by the water treatment plant or when the fishes are dead.

Water pollution changed the water quality, which could be detected through the changes in pH, concentration of dissolved oxygen, conductivity, turbidity, and temperature of the water. All these water quality parameters can be measured using specific water sensors. The following descriptions explain the details of these parameters:

• Wastewater such as acid mine water can change the water's pH, which in turn can harm animals and plants in the water. Excessively high and low pHs can be detrimental to water usage.
• Dissolved oxygen (DO) is one of the most important indicators of water quality. DO is essential for the survival of fish and other aquatic organisms. The water contamination by sewage, organic-based chemicals, household waste, food waste, and eutrophication reduced the DO level in the water.
• Conductivity is a measure of the ability of water to pass an electrical current. Conductivity in water is affected by the presence of substances such as chloride, nitrate, sulfate, and phosphate ions. Sewage pollution would raise the conductivity because of the presence of chloride, phosphate, and nitrate ions. An oil spill would lower the conductivity.
• Turbidity is a measure of the amount of suspended material in the water. It describes the clarity of the water. Suspended materials in water, such as clay, silt, and algae, reduce water clarity and cause turbidity.
• Some human activities can affect water temperature. These activities include the discharge of cooling water or heated industrial effluents, agriculture and forest harvesting (due to effects on shading), urban development that alters the characteristics and path of stormwater runoff, and climate change.

To date, the commercially available Multiprobe is a multiparameter instrument that collects the data regarding water quality parameters using user-replaceable sensors such as temperature, dissolved oxygen, pH, conductivity, turbidity sensors. This instrument is often brought to the sampling sites by environmental scientists to record the water quality parameters during sampling. The major disadvantages of the commercially available multiprobes are (i) it only provides instantaneous data, (ii) unable to monitor and provides data illustrating temporal variability, and (iii) Not possible for long-distance monitoring, and (iv) expensive.

In this project, we built a low-cost IoT-based water pollution monitoring device. The developed water quality monitoring system can monitor dissolved oxygen, pH, conductivity, and turbidity of water (Figure 1). We have also associated the weather station with this system to monitor the temperature and humidity of the surrounding. We named this system as Wireless Water Monitoring Station (WWMS). Different from the commercially available multiprobe instrument, this system was built using a low-cost microcontroller, TTGO T-Call ESP32 with SIM800L GPRS Module. TTGO is equipped with the GSM module that enables the system to connect to the internet and send the reading of the measured parameters to Google sheet or Thingspeak. The user can access the data and monitor the changes in the water quality without a presence at sites. The cost of this water monitoring system is ~USD720, which is around 20-50 times lower than the commercially available multiprobe instrument.



Figure 1: Design of WWMS.

WWMS is power up using lithium-ion batteries. To ensure this system can be deployed in the areas without power supply, a solar panel is set up to recharge the lithium-ion batteries using solar power (Figure 2). Currently, WWMS was built in the laboratory using a breadboard for the electronic circuit, and 3D printed probes holder (Figure 3). This project is not yet completed. We are transferring the circuit to PCB. Onsite testing will be carried out when the PCB is ready. This prototype will be patented when it is ready.