Construction of 318 MLD (70 MGD) wastewater treatment plant at Coronation Pillar, Delhi  Featured

L&T Construction delivered Coronation Pillar, a new wastewater treatment plant in New Delhi, treating 318 million liters of sewage a day, while reducing annual carbon emissions by approximately 14,450 tons.

By using a dynamic 3D modeling and structural analysis approach through STAAD, they achieved land savings of 17.8% and reinforced cement concrete material savings of 5%, reducing both the project’s physical and carbon footprints. Their new approach, using Bentley’s application, now serves as a benchmark, resulting in significant added value across other L&T Construction projects as it allowed them to quickly analyze different structural designs, reduce the time and arrive at an optimal solution by 75%, compared to manual design approaches.

Project Scope

The project required multiple structures to be designed and constructed within a confined site amid liquefaction and seismic risks. These are briefly summarized below:

• Sequential batch reactor
• Membrane bio reactor
• Activated sludge process
• Fixed bed activated sludge process
• Extended aeration
• Moving bed biological reactor
• Tertiary treatment with ultra filtration and reverse osmosis

Project Challenges and Bentley’s STAAD Use

Due to restricted space and the intricate form of the tank and the framed components, the project faced major obstacles. Some of the major challenges include the complex geometry, the usage of manual spreadsheets, the exact behavior of the combined structures and posed risks of liquefaction and excessive settlement due to earthquake vibrations. The resolution included switching over to STAAD.Pro software from manual spreadsheets. In other words, Finite Element Modeling (FEM) and Finite Element Analysis (FEA) adopted for integrated modeling of frame and tank structure while structural sizing optimization was based on iterations. Here, it should be mentioned that 17,800 vibro stone columns were installed as GI technique while it is also outlined that Bentley’s use in the project was crucial in all steps. Bentley’s contribution mainly concerned the primary treatment unit, the integrated centrifuge and digested sludge storage tank and the anaerobic sludge digestor.

Learn more about STAAD

Project Outcomes

Significant outcomes of the project are pointed out in this subsection. Initially, the exact behavior of all integrated structures with accurate load distribution and accurate results obtained from STAAD which in turn benefited in easy approvals. Furthermore, a 10% reduction in design manhours for 75 units and 492nos deliverables and a 5% reduction in civil quantities was succeeded. Regarding the land space, 18% savings in land space due to optimized design was obtained and a reduced plot area of 32400Sqm led to around 1 billion saving. Finally, the digital transformation encompassed aspects such as quantity extraction and the integration of virtual reality within the Building Information Modeling (BIM) lab, another point of special interest that is included in the project’s outcomes.

Environmental and Social Sustainability

Environmental and social sustainability can be encompassed through five key points. The primary pillars of environmental sustainability involve sewage treatment, carbon emission reduction, material wastage minimization, along with the generation of biogas power. The remaining two dimensions focus on manhours and land saving, as previously discussed. The first aims to serve a population of 3 million by adhering to NGT guidelines for sewage treatment and subsequent release into the river Yamuna. Additionally, there is a reduction of 14,450 tons of CO₂ emissions and a 10% decrease in material wastage, specifically in rebar and shuttering. On-site biogas power generation of 70 MW/day is implemented to decrease the Sewage Treatment Plant's dependency on the power grid. In all, the project has successfully achieved 4.52 million safe manhours and a notable 18% reduction in land usage, only in the Delphi area.

The project was presented at the The Year in Infrastructure and Going Digital Awards (YII 2023) as a finalist in the Structural Engineering category.