Case Study: Tough Sewer Clearance for Thames Water in London SE1

A Lateral Approach from IWJS Achieved a Solution for Thames Water


Thames Water was presented with what seemed to be an insurmountable and potentially extremely expensive sewer clearance problem. However a solution was found to be at hand, courtesy of IWJS, when they took over this new challenge for major client Thames.

The serviceability of the sewer located at Waterloo in London had become severely affected by 8 cubic metres of C40 high strength, heavy construction grade cement. This challenging situation seemed a thorny problem that could have presented enormous civil engineering costs potentially for the client and caused major disruption. Especially as the sewer was located within a highly busy central London urban area, therefore it was difficult to rectify the problem without affecting traffic flows adversely for prolonged periods.

IWJS was therefore tasked by Thames to come up with a more creative, cost effective solution, without resorting to a radical and hugely expensive civil engineering intervention. Following a comprehensive survey of the sewer initially by IWJS, to ascertain the full extent of the problem, a full sewer clean was then scheduled. This would follow after the careful removal of the concrete and silt from the 1.2 metres elliptical profile sewer approximately 160 metres in total length.

The Challenge Ahead

Presented with the task, IWJS examined the problem thoroughly from an open perspective that required lateral thought and ingenuity to arrive at a workable solution. A uniquely creative approach was proposed by IWJS, working collaboratively with civil engineering partners, as this was found to be the best way forward, to achieve a cost effective solution. Thames Water therefore commissioned IWJS to head up and carry out the project.

IWJS acted as the principal contractor working alongside First Intervention Team (F.I.T) and major civil engineering partners Amey and McAllister.

Early planning meetings took place to orchestrate the smooth delivery of the project and minimalise any disruption to the area.  With essential traffic management being arranged to provide a temporary bus stop suspension and pavement closure within 2 metres of the curbside. Due to the busy central urban area, much night working had to be employed to deliver the project with as little impact as possible.

The adopted plan was for the McAllister crews to enter in the upstream manhole outside a public house. There inserting bungs to stop the flow, enabling the Amey mining crew to enter at the downstream manhole to drill out the offending concrete from the line. IWJS positioned a tanker adjacent to the upstream manhole strategically, to control the flows safely around the clock, enabling the work to continue unimpeded for the teams working below in the sewer.

Obstacles to Overcome

However, upon closer inspection the McAllister teams were unable to insert the bungs, due to excessive silt constricting the line.  IWJS then carried out a line clean of approximately 130 metres downstream to remove the silt effectively, thus allowing this essential operation to proceed smoothly as planned.

The McAllister team was then able to enter the manhole to insert the bungs and inflate them. Once these were in position and inflated, the Amey mining team was then able to enter the manhole downstream to commence drilling and secure removal of the concrete. With the rescue team (F.I.T.) on hand for all entries into the manholes to ensure maximum safety at all times.

A Positive Outcome

The safe removal of the highly tough concrete proved to be a laboriously slow process. However, once all of the concrete had been removed from the sewer successfully, IWJS was then able to carry out a full clean and provided a further monitoring survey to ensure the line was completely free. The end result of this challenging project, to restore the compromised sewer back to a free flowing line, was achieved effectively. Thames Water was highly delighted with the outstanding results attained, with minimal cost and disruption to their services and the area.

With the mission being fully accomplished, Thames gratefully acknowledged IWJS for their professionalism and skill in managing such a challenging and difficult project.



40th Anniversary Celebration vehicles

As part of their 40th year anniversary celebrations, IWJS are having every new vehicle delivered this year with specially designed livery. The vehicles will be a mix of JHL and Muller build with most of them coming in special edition black with gold and silver livery. The first black vehicle arrived this week and we think it looks great! IWJS pride themselves on exemplary service levels and absolute commitment to exceed customer expectation. Please contact us for more details.


New IWJS Screeners Make Big Saving for Thames Water


IWJS has taken delivery of 2 new CD Enviro portable screeners for its main Southern fleet operations.

 The MSU-10 screener has been purpose designed to facilitate efficient liquid and solids separation for a variety of applications. The design of the MSU-10 into a single unit allows for transportation by a standard skip loader vehicle for easier site access. Obviating the need for crane lifts and associated risk assessments and method statements, reduced transportation costs and ensures a rapid set up on site.

Commenting on the savings that the new screeners can make for its clients when used in suitable applications, Peter Maasz, Business Development Director, for IWJS Ltd said:

“On their first outing to a Thames Water site they reduced 900m3 (over 1,000 tonnes) of heavy grit and rag to just 48 tonnes, which gave a massive saving to the client. Obviously this means we can offer similar savings to our other major clients in the water utilities and also to customers in associated industries. In addition these new screeners also offer significant environmental benefits by reducing tanker movements to a minimum.”

The units ensure operating costs are kept to a minimum with a generator of no more than 40Kva to run the unit. The unit is pre-wired and fitted with its own custom designed control panel, isolator and electrical sockets for easy connection to power sources available on site.

The benefits to IWJS customers include increased speed and operational flexibility when responding to particular needs at a given site. Resulting in much more efficient screening of waste water solids to achieve a highly significant reduction in excess bulk water when tankering away from locations to reduce costs.

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IWJS pledges £50,000 to help Macmillan support local people affected by Cancer


Local company Industrial Water Jetting Systems have pledged to raise £50,000 for Macmillan Cancer Support. Following both Grandparents of Managing Director Christopher Stewart being diagnosed with cancer and the invaluable care Macmillan gave in looking after them, IWJS is proud to support the Charity.

The Company is pledged to raise £50,000 for Macmillan Cancer support, which could help Macmillan pay for a Macmillan nurse for a year and will go in to helping make sure that ‘No One Faces Cancer Alone’. Christopher Stewart, Managing Director of IWJS said:

“Macmillan have been very supportive to my family during many tough days, their commitment, understanding and absolute kindness was overwhelmingly appreciated by my family. We are very proud to be working as a partner to Macmillan and we are looking forward to raising as much money and awareness as we can”.


IWJS will be raising the money through a mixture of payroll giving by every first £1 being matched by IWJS, employee fundraising such as bike runs, Macmillan coffee mornings and they will be donating £5 to Macmillan for every job undertaken by their Macmillan branded vehicles. A total of 4 vehicles have been specially branded with both the IWJS and Macmillan logos by Colchester company Premier Signs. Three of the four vehicles are combined jetting tankers and one is a support unit. Helping to support Macmillan nationwide. Macmillan Fundraising Manager said:

“It is so wonderful to be able to work with a company as passionate as IWJS. They are truly behind the Macmillan cause in making sure that ‘No One Faces Cancer Alone’ and are working with us to not only support their employees, but also to inspire others they come into contact with to get Macmillan’s support”


Macmillan London Marathon