Climate Resilient structures of the Faecal Sludge Treatment Plant (FSTP) in the context of Assam and North-east Region

 Overview of Climate Resilient Structures of FSTP

Climate plays an important role and is considered one of the main designing aspects and challenges to Urban Faecal Sludge and Septage Management (FSSM). The processes occurring in the operations of a Faecal Sludge Treatment Plant (FSTP) are subsequently affected by climate. Hence, a sustainable design plan or a climate resilient plan of the FSTP will help protect from the impact of climate change.

The design and maintenance of the FSTP should have climate-resilient features to ensure preventive measures are included to mitigate any potential impacts of extreme weather events. The design and construction of the FSTP should be assessed with the best available climate data and historical weather data. A general description of the infrastructure like the method used for the treatment processes, location, historic climate, and other relevant factors should be identified and documented. 

It considers the following points for the design, construction and maintenance of FSTP:

·       Assam is situated in northeast India with a high precipitation rate and is always vulnerable to floods. Considering the extreme weather conditions, the site selection should incorporate structures that are elevated above the High Flood Levels (HFL),

·       The placement of the treatment module should follow the ground slope of the site to ensure the gravity flow of sludge/septage, wherever possible,

·       The site and the treatment plant area should be accessible in different weather conditions,

·       The design aspects should ensure the reliability of water sources and sanitation services throughout the year even during extreme weather events like floods and drought.

·       Civil structural designs should consider the impact and protection of Seismic Zone 5 activities.

·       Sustainable operation and maintenance plan of FSTP even during extreme weather events like floods and drought.

·       Usage of renewable energy sources wherever possible to help reduce greenhouse gas emissions.

·       Disposal mechanisms of waste, treated water, residue compost or sludge should be as per the regulatory framework of governing bodies like the Pollution Control Board (PCB), Central Ground Water Board (CGWB) and related Environmental Acts.

We have provided a Resilient Design Strategies Matrix (for FSTP site development) that may be referred.

     A. Design for Flooding:

1. Structures to be elevated above the High Flood Levels (HFLs)

• Also consider free board (safe distance from high flood level to bottom of the structure) as a factor of safety to compensate for unknown factors.

2. Protect electro-mechanical equipment from flooding. Need to cover with plastic box, use the insulated sheet on the floor while using equipment. Keep the fire extinguisher ready.

3. Install sewer backflow preventers, wherever possible.

4. Improve drainage control and any intrusion into occupied spaces.

5. Use open space areas to improve the detention and infiltration of excess stormwater that may result from flooding.

6. Make Design for storm water infiltration.

7. Usage of permeable pavement structures wherever possible to allow run-off water to percolate during heavy rains.

8. Protect critical assets with barriers.

9. Incorporate green infrastructure and construct the excess water management structures.

B. Design for Extreme Heat:

1. Cool or reflective roofs.

2. Plant trees to provide shade to dwellings and control dust.

3. Provide adequate ventilation.

4. Provide shaded outdoor gathering space or working space.

5. Plant trees to provide shade and control dust.

6. The composition of road surfaces should be adapted for any impact of deformation during high temperatures.

C. Design for Heavy Rainfall and wind:

1. Structural design to provide protection from hailstorms and strong winds.             In case of hails storms and strong winds. Height of roof should be less, and           material should be used as per Indian standards codes.

   Design of the structures should be done as per following guidelines of seismic     zone 5 as Assam comes under this zone. Provide Toe wall to prevent the land     slide and soil erosion during rainfall.

2. The inlet and outlet point of constructed/natural drain system should maintain adequate channel size for unrestricted water flow.

3. Plant trees and set up the green belt to improve infiltration of stormwater and follow the guidelines of pollution control board and NGT.

4. Structural design to provide protection from hailstorms and strong winds.

5. Foundation of the structure should be connected into the wall and also should consider the IS code 456:2000 for the designing of RCC structures.

6. Green belt area should be developed by less height and deep root plantation should be used.

D. Design for Power Outrages:

1. Design for natural daylighting

2. Critical loads are to be provided on separate electric circuits.

3. Usage of solar-powered equipment like solar panel and on-grid metering connection for energy reduction.

4. Solar lights to be provided, wherever possible.

E. Operation & Maintenance Strategies:

1. Train O&M staff on specific resilience aspects of their work, as needed.

2. Ensuring the agency on board considers ease of cleaning and maintenance of FSTP at the designing step

3. Clear signage must be maintained, and damaged or missing signs should be replaced, as needed. Signage should highlight the features, functions and benefits.

F. Other Strategies:

1. Usage of potable water in construction to be minimized

2. Usage of sensors to be advocated for minimization of water usage or promotion of water conservation.

3. Any non-biodegradable waste is to be handed over to authorized recyclers only.

4. The construction site should incorporate dust, smoke and debris prevention measures.

Plastic/tarpaulin sheet covers to be used by vehicles bringing in sand and material to the construction site.