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Bethnal Green, Marian Place

The client:St William Homes (Berkeley Group)
Services:Contamination remediation, gasholder decommissioning, obstruction removal, earthworks, materials management, drainage installation, canal wall construction

The Challenge:

Cognition Land & Water Limited was contracted by St William Homes (Berkeley Group) to undertake gasholder remediation and enabling works at Marian Place, Bethnal Green, London.


Marian Place Gasholder site is a 4.53-acre (1.83 ha) brownfield site, located in Bethnal Green, within the London Borough of Tower Hamlets (LBTH). The site comprised 4 gasholder voids, a Pressure Reduction Station (PRS), substation and associated structures, and hardstanding. Two of the above ground gasholder guide frames, to the north, remain in-situ. The northern part of the site, including the gasholders no.2 and no.5, are located within the Regents Canal Conservation Area.


The project includes the enabling works and contamination remediation required to facilitate the redevelopment for a mixed-use development comprising 565 homes. Cognition’ scope included:

·       Site & vegetation clearance

·       Service disconnections and removal of redundant utilities

·       Demolition of ancillary buildings, removal of basements, foundations, slabs, and obstructions

·       Gasholder demolition (dumplings) below ground level

·       Soil remediation including processing, segregation, and classification

·       Asbestos removal

·       Sheet piled canal wall construction

·       Drainage installation, including attenuation tank construction

·       Environmental monitoring, sampling, testing, and verification

·       Backfill and compaction, utilising site won material

·       Construction of piling platforms including UXO clearance, probing and piling attendance

·       Sheet piled canal wall construction

·       Installation of site wide drainage infrastructure

·       Validation & Verification reporting

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The Approach

Our approach to the remediation was to retain as much of the soil on site as possible minimising disposal, which was more sustainable and cost efficient for the project. Through extensive sampling and testing of site won materials and pre-treatment of waste via in-situ stabilisation, we were able to re-categorise approximately 500m3 of Hazardous waste into Non-Hazardous, saving significant disposal costs. Soil and demolition arisings were reused on-site through application of DoWCoP and the EA Quality Protocol.

Environmental Monitoring in sensitive location

Due to the proximity of the site to existing housing on all sides of the site, we carried out extensive qualitative and quantitative monitoring at the perimeter of the site during the remediation works. The eight Environmental Monitoring Points (EMP) provided real time data for the project team to manage the environmental impact of the works.

Monitoring included:

•         Dust

•         Noise

•         Odour/Vapours/VOCs

•         Asbestos air monitoring

Detailed Logistics Planning

The heavily constrained site, with no storage or laydown area, meant we needed to adapt our method and sequence of operations. A carefully choreographed material management plan was enacted for excavating, segregating/treating, and moving materials from one area to another, whilst avoiding disposal off site as much as possible.

Stakeholder Engagement

We liaised extensively with the Canals and Rivers Trust on the replacement canal wall, to ensure that it was designed, planned, approved, and constructed by Cognition in a manner that ensured works did not impact on the conservation area.

The Outcome

The works were delivered to the client on time and to budget, with no complaints from neighbours, and positive feedback from regulators. The works on the canal wall were completed efficiently and in compliance with all permit conditions, with minimal disruption to the operation of the canal throughout.

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