The NG-SEPCLEAN is a decentralized sewage treating septic tank developed to provide safe sanitation through treated wastewater, developed by Emergy Enviro Pvt. Ltd. The design is applicable where traditional septic tanks are unsuitable such as lack of space for a drain field, high water tables, proximity to wells or other bodies of water, and inadequate percolation. The NG-SEPCLEAN is designed for a high rate of digestion, low footprint, and reuse of treated wastewater.
Distributors / Implementing Organizations
Flow rate (L/min)
Flow rate dependant on site specifications.
0.219-0.729 L/min (Households)
1.458-21.875 L/min (Public toilets)
Power Supply Type
No power required
Sedimentation, Flocculation, Anaerobic, Aerobic, Filtration
BOD Removal Efficiency
COD removal efficiency
NH4-N Removal Efficiency
TSS removal efficiency
Total Phosphorus Removal Efficiency
Fecal Coliform Removal Efficiency
The NG-SEPCLEAN requires less land space compared to traditional septic tanks. The principle components and functions include:
- Inlet: Wastewater enters the system
- Primary treatment: sedimentation and flocculation in the Settler Unit
- Secondary treatment: aerobic and anaerobic treatment in the Digester Unit
- Tertiary treatment: disinfection and filtration through the Filtration and Disinfection unit
Provided by the manufacturer.
Manufacturer Specified Performance Parameters
The manufacturer specifies the following as performance targets:
- Improved performance compared to traditional septic tanks by 30-35%
- Retention time of 24 hours
- Low space requirements
- Solid removal efficiency (~85%)
- Organic removal efficiency (~85%)
- No operation costs
- No odour
- Lower frequency for cleaning and maintenance
Vetted Performance Status
The average removal efficiencies of the Decentralised Wastewater Treatment System (DEWATS) in Nepal is 96% TSS, 90% BOD5, 90% COD, 70% NH4–N, 26% TP and 98% FC.
Wastewater must be handled, treated and disposed of in accordance with hygiene and environmental standards.
Complementary Technical Systems
The effluent from these digesters can be further treated through Phytorid technology as a polishing step and then dispose into the river.
Academic Research and References
Singh, S., et al., 2009, “Performance of an anaerobic baffled reactor and hybrid constructed wetland treating high-strength wastewater in Nepal – A model for DEWATS“, Ecological Engineering, 35, pp. 654-660.
Kerstens, S. M., et al., 2012, “Evaluation of DEWATS in Java, Indonesia“, Journal of Water, Sanitation and Hygiene for Development, 2, pp. 254-265.
Reynaud, N., Buckley, C., 2015, “Field-data on parameters relevant for design, operation and monitoring of communal decentralzed wastewater treatment systems (DEWATS)“, Water Practice and Technology, 10, pp. 787-798.
Compliance with regulations
Design and construction in compliance with IS 2470-2 (1985): Code of practice for installation of septic tanks, Part II: Secondary treatment and disposal of septic tank effluent.
Enlisted in the Ministry of Drinking Water and Sanitation innovative products list.