July Developments Part II

The concrete pours in the 2 day area were completed on July 20th involving Scarlet, one of the B&V subcontrators for this project.

In the 21 day area, design of the connections was reconsidered with a manhole incorporated. Complex existing services below the ground were also found, presenting a temporary logistical nightmare which was later dealt with.

The handover certificate for the manholes in order to begin work on the thickener building were handed to B&V from Yorkshire Water and it may be noted that to ensure quality, all man holes were dug by hand so as to prevent any potential risk that may have ensued from the use of an excavator.

Particular focus was given to meeting programme timescales

"Quality is never an accident; it is always the result of high intention, sincere effort, intelligent direction and skillful execution, it represents the wise choice of many alternatives"

- William A Foster

July Developments

Fill to the 2 day area is substantially completed with trimming of the 2 bases to be undertaken when the valve chamber contruction is complete.

In the 21 day area, the pipelines are progressing with the bulk of the excavation works completed.

With regards to health and safety, the roadways are marked up with requirements to paths and access to be implemented with a fully developed traffic management plan by the end of the month

"Nothing great was ever achieved without enthusiasm."

-Ralph Waldo Emerson

Use of Recycled Imported Material

Use of recycled imported material and reuse of in situ excavated material:

Knostrop is the main Waste Water treatment Works serving the city of Leeds and the scheme is valued at circa £10m and programmed for completion over an 18 month period ending June 2008.

The scheme is to design and build a new sludge management and odour control process including associated new structures to provide sludge storage, sludge thickening facilities and all the necessary activities to fully integrate the new process into the existing operations on site.

During the initial excavation stages of the scheme, unforeseen previously buried demolition waste was discovered comprising large concrete slabs and brickwork to a total quantity of circa 30,000 cu metres. It was a requirement of the design that all demolition waste discovered would be removed and replaced with suitable engineering fill.

A decision was made by the site management team to bring a licensed mobile concrete crusher on to site to crush the discovered demolition material. This produced approximately 20,000 cu metres of graded fill material suitable as backfill for the new sludge storage tank facility that was being constructed. The crusher waste product was of a very fine grading and used for landscaping around new works (10,000 cu metres).

There was still a shortfall of suitable backfill material needed for the new structures so rather than source new "virgin" aggregates it was decided to try to source some local and suitable recycled material. Enquiries led to two likely sources from:

• Another contractor on the Knostrop site who was producing surplus material (concrete and masonry) from their capital works (1000 cu m)


• From an approved Waste Transfer Station situated in the immediate vacinity of the works who was also B&V's appointed waste contractor for the scheme (3000 cu m).

It was necessary to have the material from both these sources suitably processed/ crushed and graded to the specified quality. Furthermore in order to be allowed the import of this material to the B&V site it was necessary to obtain the Environment Agency approval for a Waste Management Regulations 1994 Exemption (schedule 3, paragraph 19a - "arisings from demolition or construction work... suitable for use for purposes of relevant work.."). This approval was successfully obtained prior to imports commencing.

Any additional material used on the project was a recycled demolition waste graded fill sourced from a local supplier therefore all backfill used on the scheme was provided either from reuse of exisiting material on site or from locally imported recycled material after suitable processing.

- John Thornton

June Developments

June represented a real turning point with regards to health and safety in order to set the standard for increasing activities on the site.
We also focused on the reduction of our carbon footprint by excavating the existing poor ground and hiring a crusher to recycle the results to use for the fill in the 2 day area. This also minimised pollution by having less vehicles bringing imported materials.
In the 21 day area major diversions were put into place including the critical final effluent main serving the incinerator and processed sludge mains.
Most of the sub contractors were also put into place during this month e.g. Lintott, Monsal and A Consult for the tank walls.

"Knowing is not enough; we must apply.Willing is not enough; we must do."

-Johann Wolfgang von Goethe