The document discusses Decentralized Wastewater Treatment Systems (DEWATS), which convey, treat, and reuse or dispose of wastewater from small communities and buildings in remote areas. DEWATS provide a sustainable way to treat wastewater locally without external energy inputs using modular treatment methods. They typically include settlers to separate solids, baffled tanks for primary treatment, anaerobic filters, planted gravel filters, and polishing ponds for final treatment before reuse or discharge. DEWATS provide efficient wastewater treatment for flows up to 1000m3/day with low maintenance costs but require significant land area.