The need for automation and measurement technologies to detect the process state has been a driving force in the development of various measurements at wastewater treatment plants. While the number of applications of automation & measurement technologies to the field is increasing, there have only been a few cases where they have been applied to the area of sludge settling. It is not easy to develop an automated operation support system for the detection of sludge settleability due to its site-specific characteristics. To automate the human operator's daily test and diagnosis work on sludge settling, an on-line SV30 measurement was developed and an automated detection algorithm on settleability was developed that imitated heuristics to detect settleability faults. The automated SV30 measurement is based on automatic pumping with a predefined schedule, the image capture of the settling test with a digital camera, and an analysis of the images to detect the settled sludge height. To detect settleability faults such as deflocculation and bulking from these images, two feature extraction methods were used and their performance was evaluated.

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This study was conducted to investigate the characteristics of the stream current detector (SCD) and charge analyzing system (CAS), which are well known as the automatic coagulant dosage determination instruments. When the SCD system was used, the current charge value set at pH 9.3 could not be used as the coagulant dosage when the pH of the raw water decreased to 5.7, and the current charge value corresponding to pH 5.7 was required to be reset. In case of CAS system, polydadmac is stable as a cationic titrant when the pH of the raw water ranged 9.3 to 6.0. And it was effective to use polydadmac as a cationic titrant for high turbidity water. The current charge of polydadmac was almost constant between pH 5 and 11, however, the difference in charge of alum is six times in this pH range. Therefore, when the pH of the raw water was changed, it seems that the coagulant used in the actual water treatment plant was as a good cationic titrant.

Objectives:This study was conducted to evaluate the detection characteristics of Nakdong River basin (wastewater treatment plant (WWTP) effluents, tributaries and main streams) by selecting 18 kinds of pharmaceuticals which were detected frequently. It was intended to be used as basic data for advanced treatment of WWTP and securing safe water source.Methods:The selected 18 pharmaceuticals investigated in this study were acetaminophen, atenolol, carbamazepine, caffeine, diclofenac, iopromide, lincomycin, metoprolol, primidone, propranolol, sulfachloropyridazine, sulfamethazine, sulfamethoxazole, tetracycline, trimethoprim, chlorotetracycline, oxytetracycline and sulfathiazole. The residual pharmaceuticals was analyzed LC-MS/MS equipped with on-line solid phase extraction (SPE) system and the limit of quantifications (LOQ) of 18 residual pharmaceuticals were 1~5 ng/L. Sampling points were 27 from the upstream to the downstream, including mainstream, tributary, and WWTP effluents. Sampling was conducted four times in Feb., Jun., Aug. and Nov. 2018.Results and Discussion:The most frequently detected residual pharmaceutical in all WWTP effluents, tributaries and mainstream sites was caffeine, followed by carbamazepine, lincomycin, sulfamethoxazole and iopromide. In addition, iopromide was detected as the highest mean concentration of 44.9~985.4 ng/L followed by caffeine (63.2~337.1 ng/L) and carbamazepine (13.8~145.0 ng/L), sulfamethoxazole (12.3~114.8 ng/L) and diclofenac (3.1~144.1 ng/L). In particular, the proportion ratio of caffeine gradually decreased as going to the downstream, whereas iopromide gradually increased. However, the concentrations of caffeine in the sampling sites of the downstream were higher than those of the upstream sites. The total concentrations of detected residual pharmaceuticals gradually increased from the upstream to the middle stream, showed the highest detected concentration at the Goryeong area in the middle stream of the Nakdong River, and then gradually decreased due to the dilution effect. Residual pharmaceuticals in the Nakdong River basin, which could not be completely removed from the WWTPs, entered into the water system and contaminated source water of the downstream. This process is a typical contaminant pattern of the source water by the emerging micropollutants.Conclusions:The most frequently detected residual pharmaceutical in all WWTP effluents, tributaries and mainstream sites was caffeine, followed by carbamazepine, lincomycin, sulfamethoxazole and iopromide. In addition, iopromide was detected as 44.9~985.4 ng/L, showing the highest mean concentration at the sampling points, and caffeine (63.2~337.1 ng/L) and carbamazepine (13.8~145.0 ng/L), sulfamethoxazole (12.3~114.8 ng/L) and diclofenac (3.1~144.1 ng/L) in order. The total concentrations of detected residual pharmaceuticals gradually increased from the upstream to the middle stream, showed the highest concentration at the Goryeong area in the middle stream of the Nakdong River basin, and then gradually decreased due to the dilution effect.