Slow-releasing tablets combined with persulfate acting as an oxidant and ferrous iron acting as an activator were manufactured for in situ chemical oxidation. The trichloroethylene (TCE) removal efficiency according to the molar ratio of the oxidizer and activator in the 0, 0.5, 1, 1.5, 2, and 2.5 molar ratio (persulfate: ferrous iron) reactors were 15%, 89%, 90%, 82%, 71%, and 55%, respectively. In a batch reactor injected with an oxidation-activation combined tablet (OACT) and a liquid oxidizing/activator, the TCE removal efficiencies were 100% and 70%, respectively, showing that the tablet form had a high efficiency in contaminant removal. The evaluation of the dissolution characteristics and TCE removal efficiency of OACT 0.5 (tablet with a 1:0.5 molar ratio of persulfate to activator) and OACT 1.0 (tablet with a 1:1 molar ratio of persulfate to activator) under continuous flow conditions showed that the TCE removal efficiency of the OACT 1.0 column was approximately 1.4 times higher than that of OACT 0.5. The longevities of persulfate and ferrous iron of the OACT 1.0 tablet were 43.2 days and 41.7 days, respectively. Thus, OACT 1.0, which was manufactured effectively, was suitable for in situ slow-release chemical oxidation systems.

This study aimed to investigate the influencing factors and characteristics of granule morphology through approximately 500 d of long-term monitoring of two types of anaerobic–aerobic phosphorus-accumulating organism (PAO) and anaerobic–anoxic denitrifying PAO (DPAO) sequencing batch reactors (SBRs). The results show that granules were present in the DPAO SBR and PAO SBR after 200 d and 250 d of operation, respectively. The average diameters of the granules were 2.2 ± 0.7 mm in the DPAO SBR and 0.4 ± 0.3 mm in the PAO SBR, respectively. The DPAO granular sludge contained rod-shaped microorganisms, whereas the PAO granular sludge contained cocci-type microorganisms. A precipitated core consisting of hydroxyapatite was found in the DPAO granules. A comparative analysis conducted under various operating conditions revealed that the availability and type of the electron acceptors (EAs) may have a significant impact on granulation. This observation suggests that the presence and diversity of EAs are crucial factors for the development of different granule sizes and morphologies.

Urban stormwater runoff, particularly during first-flush events, carries high loads of fine suspended solids and phosphorus that are difficult to remove with conventional best management practices (BMPs). This study developed and evaluated a laboratory-scale high-efficiency up-flow filtration system with Internet of Things (IoT)-based autonomous control. The system employed 20 mm fiber-ball media in a modular dual-stage up-flow configuration with optimized coagulant dosing to target fine particles ( 1000 mg/L, TP ~1.6 mg/L), the system maintained >90% SS and ~58% TP removal with stable head loss (~8 cm) and no manual intervention. Turbidity correlated strongly with SS (R² ≈ 0.94) and TP (R² ≈ 0.87), validating its use as a surrogate control parameter. Compared with conventional BMPs, the developed filter demonstrated superior solids capture, competitive phosphorus removal, and the novel capability of real-time autonomous operation, providing proof-of-concept for next-generation smart BMPs capable of meeting regulatory standards while reducing maintenance.