CHERTS is a compact, prefabricated domestic wastewater treatment system designed for decentralized and off-grid applications. It is specifically engineered to be installed downstream of existing septic tanks to provide advanced secondary treatment. With a treatment capacity of 500–1500 gal/d, it serves approximately 10–40 people and delivers effluent that meets NSF/ANSI 40 and 245 requirements while minimizing operational complexity. Maintenance is straightforward, requiring only two quick 20-minute checkups per year, with sludge removal needed once every two years. Its underground installation requires minimal surface space, allowing CHERTS to integrate discreetly into residential environments while offering a durable, efficient, and user-friendly wastewater treatment solution.