Location: England
Crossness Sewage Treatment Works is one of the UK’s largest and oldest waste
water treatment facilities, with concrete assets that have been in service for over 150 years. McFarland Consulting Ltd were appointed to undertake a series of investigations to deteriorating reinforced concrete structures to support remedial decision-making and long-term asset management.
MCL were appointed initially to investigate deteriorated walls within a preliminary treatment channel, with the scope subsequently expanding to include nine locations across the works over a two-year period. The investigations comprised detailed visual inspections, hammer tap surveys, covermeter and GPR surveys, durability testing and laboratory analysis of extracted samples, including chloride, sulphate and petrographic testing.
A significant proportion of the investigations were undertaken within complex medium-risk confined space environments. Access arrangements varied widely and included rope access, underground scaffolding systems, crane-mounted man baskets and confined space entry, all of which were carefully planned and coordinated to maintain safe working conditions within an operational treatment works.
The interpretative reporting provided the Client with a clear understanding of the extent, severity and causes of deterioration affecting the concrete assets. MCL’s recommendations enabled targeted remedial interventions to be developed, supporting the restoration of structural integrity and extending the service life of these historically significant structures.