IWJS makes big savings for Anglian Water at Cliff Quay

Cliff Quay Screener

IWJS made significant savings recently for client Anglian Water and main contractor Morrisons at Cliff Quay in Ipswich. This was achieved through the use of the portable screening units employed by IWJS on the site that effectively reduced the original volume of water to an absolute minimum for the client.

Details of the Works

The waste was thought to contain approx. 30% rag 25% grit with the remainder being sludge. Man entry into the tank was not possible so all works had to be done via the roof access and then the side hatch later on; entry was made once no more waste could be removed using this method.

The Resources Employed

  • 1 x Air movement Flex vac deep suction unit
  • 2 x Dewatering Screening Units (1 x course screen 1 x fine screen)
  • 2 x 6 “sludge pumps, 1 x 4” Washwater/Supply Pump
  • All associated equipment/ACoP personnel for Entry work

Method Adopted to Achieve Significant Savings

Historically, traditional methods would use a tanker to transport the entire waste volume to licensed disposal which, in this case would cost approx. £120k for the tankering & disposal alone. With access being limited and the tank filled with old heavy ragged sludge and grits a standard suction combination unit would not be able to extract the waste. IWJS deployed a Flexvac air movement unit which has 4x the suction power. To deal with the large volume of waste IWJS proposed to dewater and separate the waste using a screening method. This simple treatment would significantly reduce the amount of waste for disposal and give more options. IWJS deployed 2 CDE MSU:10 screening units, one fitted with a 6mm course screen bed and the other a 75 micron unit. This set up delivers a three-way split for the waste, rag, grits and liquids.

These screening units are bespoke to the waste water industry and are built using heavy duty quarry technology parts. They are also very compact, taking up the space of a skip. High pressure water wash bars help to clean the waste and the large screening beds vibrate at high speed to facilitate the dewatering treatment.

Impressive Results

The waste was reduced from 1200m3 down to approx. 60m3. The final split between grits and rag was 50/50 with the screened/washed grits staying on site and put through AWS composting facility. This left just 30m3 going for off- site landfill disposal which equates to just 2.5%. This equates to a massive saving of more than 97% on the original volume of waste water. Commenting on the significant savings made for Anglian Water, Peter Maasz, Business Development Director at IWJS said:

“Apart from the significant cost savings for Anglian, it’s the dramatic saving in the original volume of waste to landfill that’s particularly impressive, more than 97%. The actual solids were reduced down to a mere fraction and naturally, this had a major impact on the amount of tankering that was finally needed on the job with major benefits to the environment.”

 

deep sewer CCTV survey

UUTS Manchester University Sewer Survey

Project:                     Manchester University Build Over

Client:                       United Utilities Total Solutions Ltd:

End Customer:        Manchester University

Location:                   Materials Science Centre Upper Brook Street, Manchester

CCTV sewer survey

CCTV sewer survey

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Project Background:

Manchester University want to construct a new building over a deep United Utilities combined major trunk sewer.

The sewer is a 3.8 diameter Trunk Main located directly beneath the build over site, the precise location needed to be determined prior to any piling and construction works and to ensure the asset was safe from the construction activities.   The sewer is constructed in rock with a brick lining and is up to 18 metres below ground level.    To assist with the build over design a pre-condition survey was required so that UU could approve the design and sanction the construction.    On completion of the build a post construction survey is also required.

Access to the sewer was problematic due to limited access points, depth, multi landings, high flows and side entries.   The sheer size and flow levels also meant conventional crawler mounted CCTV and Man Entry surveys were ruled out.

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Stage 1

A recce of all located chambers was undertaken to determine equipment access issues, rescue techniques and the survey method.   Detailed surveys were undertaken of all manholes and landings supported by diagrams and photographs which enabled the RAMS to be prepared and access permits granted.

Stage 2

Following several site meetings with representatives from the University, the construction Design Consultants, United Utilities operational and management staff and IWJS Managers and Supervisors an acceptable method was proposed and eventually accepted once it was vigorously checked by the relevant health and safety departments of all concerned .

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Stage 3

Using a high volume combination unit as a winch device we towed an inflatable raft complete with a CCTV platform and location probe from a number of limited access points over a period of three night shifts.   A four man, high risk confined space entry team were required to position the equipment and inflate the raft below ground using protective sheets to avoid puncturing the floatation device when installing and retrieving it.  The whole project was supported by a six man IWJS Rescue Team complete with BA equipment in case of safety alerts or in sewer incident.

During the survey an above ground mapping team was engaged to locate the sewer using a transmitting sond attached to the raft which was picked up on the surface with an RD7000 radio detection device.   All points marked on the surface were then surveyed using a GPS unit which accurately pin pointed all signals received to enable the sewer route to be created on a CAD drawing.

All works were in accordance with:

  • Confined Spaces Regulations 1997
  • The Management of Health and Safety at work regulations 1999
  • Water Industry act 1991
  • Water Act 2003
  • Flood and Water Act 2010.

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Stage 4

Provision of survey report including:

  • Summary of findings
  • Details of all points of interest
  • CCTV recording on DVD

CAD drawing of survey results showing:

  • Points of damage and extent (if known)
  • Points of erosion and extent (if known)
  • Other areas of interest
  • Depth and level recordings

Relining expertise at IWJS

The Task
What to do when you are faced with having to reline a 38m section of 750mm storm drain in a very demanding environment?

The site conditions meant that access to one end of the drain was on rough ground that suited 4×4 vehicles, the other end in tight residential roads a further 30 m on from the end of the relining section. In between, the drain running under houses and other structures.

When a major Water Utility company was faced with this particular set of problems, DSS Environmental Ltd demonstrated they had the capabilities and won the contract to undertake the works.

What we did

The three day project started by digging down to reveal the storm drain, cut through the top to gain access and build a tower to take the relining equipment.

Following a CCTV survey to finely assess and measure the problem section, a combination jet/vac unit was used to clean the drain followed by remote guided cutting equipment to remove tree roots.

A further CCTV survey confirmed the section was clean, clear and ready to take the liner.

The 2 ½ tonne pre-wetted (resin impregnated) liner that arrived in refrigerated transport on day two was winched through the access point and carefully positioned using the CCTV crawler as the underground eyes.

The next part of the process involved inserting a calibration liner inside the resin liner and using water to fill the ‘cali’ to press the resin liner to the sides of the drain ready for the curing process.

Using 3m BTU of heating capacity, the water in the calibration liner was heated to 80oC and kept at temperature for 8 hours to ensure the resin liner was properly cured.

Day three saw the safe removal of the equipment, a final CCTV survey to ensure the liner was fully functional and the making good of the site.

Safety is always paramount on this type of operation and the weather was constantly monitored. ‘Packers’ were used to temporarily stop the water flow throughout the three days and a Flexline tanker was on site 24/7 to over pump any rainwater if the weather turned. After all, that is the purpose of storm drains.

 The outcome

With a written report (including a CCTV survey DVD) sent to the client confirming a successful operation, IWJS have again demonstrated their expertise in the sewer relining and sewer repair sector.

Basildon Sewer Treatment Works

The Task

IWJS Ltd were contracted by ELS on behalf of Anglian Water to clean out three large storm tanks, each capable of holding 1.5 million litres of waste water, at the Basildon Sewer Treatment Works.
The storm tanks, designed to store overflow waste in times of heavy rain, had 15 years of accumulated debris to be cleared.

What we did

A phased approach was required as the treatment works had to remain operational throughout the process. Consideration also had to be taken regarding weather conditions to ensure the safety of the IWJS staff.

With the volume of debris and waste water present IWJS provided dedicated large scale vacuum pumping, high pressure jetting and screening units as well as experienced operators to ensure continuous operations.

Each storm tank took five days to clear with an additional three days work to clear the surrounding weirs and connecting culverts.

The collected solids, up to a metre thick along the bottom of the 58m long tanks, were separated from the waste water for safe disposal.

The screening of the waste as well as the recycling of the waste water during the high pressure jetting operations was an important factor in reducing the environmental impact of the operations.

The outcome

IWJS left each tank in a ‘as new’ condition to the delight of the works management team. The IWJS operators were praised for providing a very high level of service within the allocated time scales.

Pocklington Beck

The Task

Aquajet GB Limited was contracted by the Environment Agency to clear debris build up from Pocklington Beck. The activity was part of an on-going flood risk strategy following major floods in 2003 and 2007 and was subject to intense public scrutiny.

What we did

Around 350 tonnes of mainly rubble were removed. Following the clearance of the rubble and debris the beck is now free flowing and the flooding risk has been significantly reduced. However during the course of the works both native white and American crayfish were discovered in the beck.

Aquajet undertook to solve this issue with the Environment Agency. Detailed planning was required across multiple agencies. Aquajet staff caught and segregated the two species whilst recording the level of activity. The native species were released downstream away from the predatory American crayfish.

The outcome

Apart from the free flowing beck and significantly lower risk of flooding Aquajet received many plaudits for the way in which the environmental works were handled professionally and in a sensitive manner. Aquajet are a preferred supplier to the Environment Agency for clearing, CCTV surveys and other drainage services. With such dedicated staff you can see why Aquajet are thought so highly of.

Whittle Brook

The Task

Aquajet(GB) Ltd were engaged by the Environment Agency to carry out a full cleanse of this drainage asset. The condition of this asset was in particularly poor condition. In addition the work was to be carried out under tidal conditions and in a remote location.

What we did

A significant amount of debris was removed from the drain. As the site was remote, tidal and adjacent to a live railway and canal Aquajet(GB) Ltd coordinated with several other contractors to ensure that both their works and the other contractors works could be carried out in a safe and timely manner. To this end Aquajet had a Manager on site throughout the operation.

Specialist equipment was deployed during the works and man entry techniques were required supported by our own rescue team on site at all times. These teams are fully trained to a level that the Environment Agency allow them to work unassisted in the field to an acceptable safety level. Significant groundwork was required to return the asset to the required condition including landscaping, fencing and re-seeding the area.

The outcome

Another successful operation by Aquajet reducing flood risk for the Environment Agency.

Aquajet are a preferred supplier to the Environment Agency for clearing, CCTV surveys and other drainage services. With such dedicated staff you can see why Aquajet are thought so highly of.