Floc sensor prototype tested in the municipal wastewater treatment plant

Figures & data

Table 1. Inlet and outlet wastewater quality parameters of Skiphelle WWTP during the experiments period

Variables	Mean	Min	Max	Standard deviation
Inlet flow, m^3/h	190.6	75.6	346.1	60.9
Inlet pH	7.4	7.3	7.9	0.1
Inlet turbidity, FNU	161.0	55.8	500.0	78.3
Ww temperature, °C	14.4	12.9	15.1	0.5
pH after coagulant dosage	6.9	6.6	7.2	0.1
Outlet turbidity, FNU	4.5	1.6	12.7	4.0
Coagulant dose, ml/s	5.8	2.4	7.3	0.9
Coagulant dose, ml/m^3	115.6	31.6	194.3	22.9
Coagulant dose, mmol Al/l	0.53	0.14	0.88	0.1

Figure 1. (a) Schematic representation of the installation; (b) a photograph of a part of the installation – Raspberry Pi camera and imaging cell with flocs.

Figure 2. Print screens of the developed program for the Raspberry Pi camera control: (a) main page with the menu; (b) camera parameters settings; (c) time laps settings.

Figure 3. Scores plot of PCA, PC1 vs. PC2 for: (a) data with 4 GLCM textural features of the images of flocs; (b) data containing wastewater quality parameters, GLCM textural features and the coagulant dosage.

Figure 4. Comparison of the predicted coagulant dosages by PLSR and reference dosages with corresponding them effluent turbidity measurements.

Figure 5. Comparison of the sample images corresponding to different outlet turbidity measurements and the ranges of their GLCM textural features.