Real-time optical monitoring of the wastewater treatment process

Abstract

One activated sludge process line was optically monitored in situ by a novel image analysis equipment. The results of the image analysis were studied to find out dependencies to the process variables of the wastewater treatment plant (WWTP) and to the quality of the treated wastewater. The quality parameter of the treated wastewater, suspended solids, was modelled using the image analysis results. The model can be used for evaluating the performance of the WWTP and for the better control for stable effluent quality. It was shown that the results of the online optical monitoring reveal useful information from the process and can be used in forecasting the quality of biologically treated wastewater. The optical monitoring method together with process measurements has an important role in keeping the process in stable operating conditions and avoiding environmental risks.

Predicting the effluent quality of an industrial wastewater treatment plant by way of optical monitoring

“…As the flow increases, the equivalent diameter of the objects decreases and when the temperature is higher, the roundness of measured flocs is higher. In the previous studies, a municipal ASP were studied with the similar imaging system and it was noticed that the increasing flow decreased temperature [7,8]. It was also discovered that the suspended solids and other quality parameters of treated wastewater had a positive correlation coefficient with the amount of filaments and number of small objects and negative correlation with roundness and fractal dimension among others.…”

“…Optical monitoring of floc morphological characteristics is a potential tool to be used as assistance in process control as it gives fast objective information about the quality of wastewater and the state of the treatment process, reveals some of the reason for settling problems and combined to a predictive modelling shows the quality of effluent in advance hours before it is noticed by traditional process measurements. [3,2,[4][5][6][7][8] In this study, the results of the automatic optical monitoring of wastewater samples taken from a fullscale industrial active sludge process during a period over one year were utilized to develop predictive models for the effluent quality parameters (suspended solids, biological oxygen demand, chemical oxygen demand, nitrogen and phosphorus). Five variable selection methods were used for selecting the optimal subsets of input variables for each developed model.…”

Monitoring a municipal wastewater treatment process using a trend analysis

“…The traditional analyses of sampled wastewater do not provide fundamental knowledge on the wastewater quality or the essential information about the reasons for the problems in the treatment process. On-line optical monitoring of floc morphological characteristics, on the other hand, gives fast objective information about the state of the wastewater treatment process and reveals some of the reasons for settling problems [3,18,19,20,21]. The optical monitoring data used in this study was collected by a small-scale optical monitoring device which was especially designed for in-situ use to replace the slow, irregular and subjective manual microscopic analysis of wastewater samples [16].…”

Recursive Dynamic Modelling in Changing Operating Conditions

“…The coefficients and variables of the model are the same in all operating conditions. The new measurements reported in (Tomperi et al, 2015) are included in the analysis.…”

“…Heikkinen et al (2008a) used models for predicting the chemical oxygen demand (COD) of the effluent in an industrial activated sludge plant. Image analysis has been studied in (Tomperi et al, 2015) to find out dependencies to the process variables of the plant and to the quality of the treated wastewater.…”