MeteoMex Wastewater Treatment
Using domestic wastewater treatment, the consumption of clean, potable water for gardening can be drastically reduced. In combination with the solar production of electric energy (photovoltaic cells), the sustainability of a house can be further improved. The required energy for wastewater treatment depends on the volume and the charge of soluble solids which enters the plant, and the intensity and duration of aeration. Thus, observing the volume throughput and the quality of treated water support the optimization of the process and the planning of irrigation schemes.
The following flowchart shows the process of wastewater treatment, together with the solar energy supply and the connected irrigation. The MeteoMex unit sends data about the total suspended solids (TSS) of the treated water and the filling of the treated water tank.
Internet-of-Things integration
The following ThingsBoard dashboard shows the monitoring of turbidity and tank fill level.
Technical details
The sensors are connected via a custom Wemos D1 mini shield. Since the WiFi signal does not pass through the iron/ concrete construction of the plant, a Wemos D1 mini Pro with an external antenna is used. The power is supplied from the main control board of the wastewater treatment and the RainBird irrigation system. A reused plastic box is used to protect the circuit from humidity. The turbidity sensor is stuck into a piece of unicell, which allows it to float on the surface of the effluent. Both, the ultrasonic distance sensor and the turbidity sensor, produce noisy data. Therefore, the signals are produced filtered by a simple minimum filter and a Kalman filter, respectively.
Circuit design
For data processing and WiFi connections, a Wemos D1 Mini board is used.
The circuit was mounted on a custom board, which is similar to the MeteoMex terra PCB. However, the Ultrasonic sensor needs additional connections to digital Wemos pins.
The following sensors are used:
1) Jsn-sr04t waterproof ultrasonic sensor. The programming of this sensor is the same as for the popular SR04 sensor.
2) Analog Arduino sensor for total suspended solids (TSS). The sensor is connected to A0 as any analog sensor.
The example program is available from the MeteoMex GitHub repository.
Applications
- Monitoring and optimizing the performance of wastewater treatment in domestic and public plants.
- Optimization of energy use of wastewater treatment and irrigation.
- Monitoring of water use and availability in water tanks.