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.
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.”