The presence of illicit discharges in sewerage systems generates an important impact in wastewater treatment plants and the ecosystem. In this paper, we present two prototypes for monitoring the presence of solids in wastewater and to study the effect of the water height. The prototypes are based on color and infrared LEDs and two photosensors located in the prototypes at 0° and 180° degrees. When the photosensor is located at 180°, all color LEDs present a good range of output voltage (approximately 5 V to 0 V) and good R2. However, for the typical concentration of solids in wastewater, the prototypes do not work correctly. When the photosensor is located in the prototypes the LEDs, yellow, red, and white have a good operation with voltage differences of 1.73 V, 1.76 V, and 1.13 V in P1 and 1.58 V, 1.84 V, and 1.35 V in P2, respectively. We calculate the mathematical model with the heights and solid concentration. The mathematical models which do not consider height present good R2. In conclusion, when the photosensor is located in the prototype, the height does not have an important effect and can detect the illicit discharge of solids. When the photosensor is located at 180°, it can be used for water with important changes in solid concentrations.

中文翻译：

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用于检测污水中非法排放的低成本传感器

污水处理系统中非法排放物的存在对废水处理厂和生态系统产生了重要影响。在本文中，我们提出了两个原型，用于监测废水中固体的存在并研究水位的影响。原型基于彩色和红外LED以及两个位于原型中0°和180°的光电传感器。当光电传感器位于180°时，所有彩色LED都具有良好的输出电压范围（大约5 V至0 V）和良好的R2。但是，对于废水中典型的固体浓度，原型无法正常工作。当将光电传感器放置在原型中时，黄色，红色和白色的LED可以很好地工作，P1中的电压差分别为1.73 V，1.76 V和1.13 V，P2中的电压差分别为1.58 V，1.84 V和1.35 V 。我们用高度和固体浓度计算数学模型。不考虑高度的数学模型给出了良好的R2。总之，当光电传感器位于原型中时，高度不会产生重要影响，并且可以检测到固体的非法排放。当光电传感器位于180°位置时，它可用于固体浓度发生重大变化的水中。