Simple sand-and-gravel bed systems used to dewater and dry sludge through drainage and evaporation.
Sludge drying beds integrated with plants that aid dewatering and further treatment through root-zone filtration.
Working Principle:
Planted Drying Bed (PDB) is a shallow, rectangular bed consisting of multiple layers—coarse gravel at the bottom, a sand filtration layer in the middle, and a top layer planted with specific wetland vegetation such as Canna indica or Phragmites australis. The bed is open to the atmosphere and equipped with a drainage system at the base to collect leachate or percolate. Sludge is applied uniformly over the sand surface, and water percolates downward through the filter media by gravity. The leachate is collected by an underdrain system and directed to a liquid treatment facility for further treatment.
The vegetation plays a critical role in enhancing treatment performance. Plants promote drying through evapotranspiration, improve infiltration through root channel formation, and facilitate aerobic microbial activity that aids in sludge stabilization. Nutrient uptake by plants also contributes to improved leachate quality,
Suitability:
Suitable for locations with limited human resources where frequent sludge removal is not feasible
Suitable for small to medium towns with moderate sludge generation.
Performs well in tropical/subtropical climates with adequate sunlight.
Ideal where better sludge stabilization and odor control are required.
Useful in locations with high organic sludge content, requiring improved stabilization.
Pros/Cons:
Pros: Faster and more efficient drying due to plant-assisted evapotranspiration, improved sludge stabilization and reduced odor, lower risk of clogging due to root channels, reduced sludge handling frequency, contributes to a greener, nature-based solution
Cons: Slightly higher land and construction requirements, requires periodic plant harvesting and care, may require more time to establish (plant growth phase), performance may vary with plant health and season
O&M requirement:
Sludge removal every 1 to 3 years depending on design, sludge loading and drying time.
- Regular harvesting or pruning of plants to maintain root health and effective evapotranspiration.
- Monitoring plant health, replanting if mortality occurs.
- Occasional de-weeding to avoid invasive growth
- Maintenance of Sand layer
- Check and maintain leachate drainage system.
|
Parameter |
Design Value |
Unit |
|---|---|---|
|
Planted Drying Bed |
||
|
Total Solids (TS) |
30 |
Kg/cum |
|
FS loading rate on beds |
300 |
kg/m²/year |
|
Days of application in a week |
5 |
Days |
|
Factor of safety (in total area) |
10 |
% |
|
Number of beds (Total) |
10 |
Nos |
|
Number of beds operational and standby |
5 + 5 |
Nos |
|
Sludge feeding frequency per bed |
8 |
Once in Days |
|
Leachate/percolate from PDB |
||
|
BOD |
200 |
mg/l |
|
COD |
400 |
mg/l |
|
Hydraulic retention time |
2 |
Hours |
|
Peak hours |
4 |
Hours |
|
SS/COD ratio |
0.45 |
- |
|
De-sludging interval in Settler |
18 |
Months |
The following will be the treated sewage characteristics:
|
Parameter |
At PGF Outlet |
At ACF+PSF Outlet |
Unit |
|---|---|---|---|
|
Effluent Characteristics |
|||
|
BOD |
< 30 |
< 10 |
mg/l |
|
COD |
< 100 |
< 50 |
mg/l |
• There is vehicular access available to the site.
• The site is fairly level ground, free of any structures, large trees requiring cutting permission, any kind of underground or overhead utilities, etc. except for small shrub's, vegetation, etc.
• The site is with original soil profile, without deep filling or overburden.
• The soil profile of the site involves earth work excavation in soil only, excavation involving rock blasting is not necessary.
• The site is not a low-lying area or marshy land or sewage farm, etc.
India’s rural sanitation sector has witnessed significant progress under the Swachh Bharat Mission Grameen (SBM-G), with increasing emphasis on sustaining Open Defecation Free (ODF) outcomes and strengthening Solid and Liquid Waste Management (SLWM) systems across villages. As rural communities continue to evolve and generate higher volumes of greywater and wastewater, there is a growing need for decentralized, cost-effective, and sustainable rural used water management solutions that are technically sound and easy to implement.
Despite the availability of various treatment technologies and management approaches, Gram Panchayats, Rural Development Departments, and implementation agencies often face challenges in selecting appropriate technologies, preparing technical designs, estimating costs, and planning site-specific interventions. The lack of standardized technical resources and easy access to implementation-ready designs further slows down the execution of rural sanitation infrastructure.
To address these challenges and support the effective implementation of rural used water management systems, WASH Institute has developed this dedicated web-based Rural Used Water Management Portal. The portal is envisioned as a comprehensive technical decision-support platform to assist states, districts, blocks, Gram Panchayats, and practitioners in planning and implementing sustainable rural sanitation infrastructure.
The portal provides a curated repository of commonly adopted rural treatment technologies and management systems, including soak pits, leach pits, waste stabilization ponds, DEWATS, drain-end treatment systems, co-treatment models, FSTPs and other decentralized greywater management solutions suitable for rural contexts. Each technology package includes standard design drawings, technical specifications, implementation guidance, and quantity estimates (BoQs) that can be readily adapted for field implementation.
The technical resources available on the portal have been prepared by experienced sector experts in alignment with CPHEEO guidelines, SBM-G operational guidelines, and established field practices. The technologies featured on the portal have been successfully implemented across multiple villages and states, ensuring their practicality, scalability, and suitability for diverse rural conditions.
By making standardized designs and implementation resources easily accessible, the portal aims to strengthen planning capacities, reduce duplication of technical efforts, improve the quality of infrastructure implementation, and accelerate the adoption of safe and sustainable rural used water management systems across India.
Importantly, the portal is designed as a dynamic and evolving knowledge platform rather than a static repository. It will continue to expand through contributions from sector practitioners, government departments, and technical institutions. Future enhancements will include state-specific schedule of rates, GIS-based planning support, case studies, operation and maintenance guidance, and real-time cost estimation tools to further support rural sanitation planning and implementation.
Local governments follow staged planning for grey water management projects — planning and project formulation, DPR preparation, tendering, construction, and operation & maintenance. This portal supports the tendering stage by providing standardized technical drawings and cost estimates.
The designs, drawings, and bills of quantities (BoQs) provided on this portal are intended for reference purposes only and cannot be used directly for construction. Validate design assumptions, adopt locally applicable Schedule of Rates, and ensure compliance with applicable national or state-level standards.