confined space team
Sewer cleaning is something Hydro Cleansing are the go to guys for. Cleaning a London mainline sewer requires some complex logistics and expert engineers. From cranes, to penstocks, to 500m of jetting hose, this one required a specialist approach.
The sewer had to be cleared of silt in order to allow an inspection of the sewer to take place. The line was 20% full of waste and a risk assessment had established that the risk was significant enough to require all of the silt to be removed before the inspection was undertaken.
The sewer water was diverted by lowering the penstock which sent the flow of water through an alternative sewer. This penstock didn’t keep all of the water out and so the remaining storm water had to be continuously pumped away from the chamber where the engineers were working. This was 45m deep! A crane was supplied by the client to lower in the pumps and hoses.
From there our engineers could remove the silt and MEGATRON, the largest vacuum tanker in Europe, vacuumed it up the 45m into bulk tankers for disposal. MEGA REEL, the longest jetting reel available at 500m allowed the confined space engineers to jet as far into the sewer as they were required to. This loosened the silt and meant it could be sucked up the hoses at astounding speed!
The sewer cleaning was carried out during the night as the flow of waste water is lower. Without the awesome power of Megatron, the specialist hose of Mega Reel of the expertise and commitment of our engineers, this job would have taken weeks. It was completed in a few nights!
As London smoothly continued its business, Hydro Cleansing moved into the dirty underworld of a pump station in West London. After a free site survey HCL established that four screens within it were on the verge of becoming blocked.
Four vast 4m high screens were located within a 20m deep shaft. This would be an overwhelming job for most companies. Megatron’s force was the only answer!
To accompany the beast, HCL sent an articulated bulk tanker to hold the waste and a five man confined space team. The team comprised of one topman, a two man working team and a two man rescue team. With extendible hand lances, the engineers were winched into the large space to blast the rag off even the highest parts of the massive screens. Not only vacuuming the silt and rag 20m vertically, Megatron’s phenomenal jetting force was required to cut the rag loose. A hydrant near the pump station provided a good water flow which was then blasted though the beast’s powerful hoses. These screens were fixed in place. Our confined space team worked using the jetting equipment and crow bars to chop through the rag. Lights powered by Megatron’s generator and the lights on the engineer’s hardhats lit the gloomy space.
The screens are in the pump station to act as grates to filter the solid waste, allowing the liquid waste through. Having not been cleaned for a number of years, the silt was almost at dangerous levels. Rag and solid waste caked the giant grates. Clearing them efficiently was essential. The silt that had built up behind it had to be removed and disposed of immediately. The utility company, who we were working on behalf of, closed the sewer’s pen stocks (large gates that act as valves regulating the flow of the sewer) temporarily which allowed the work to go ahead. A storm hit after the first day. The sewer had to be allowed to flow. Our team returned after the storm’s flow had abated and finished the remaining screens.
The engineers had compressed air breathing equipment on site in case it became necessary. Our confined space engineers were winched down into the space. They were equipped with masks and air bottles in case of gas emergencies and we had supplies of compressed air and hose with us in case it was necessary. The team could wear masks and have air pumped from above. Thankfully, this turned out not to be necessary.
Before, during and after cleaning the pump station screens:
We were delighted to complete this job for one of the South East’s largest utility companies. Our engineers’ hard work and the almighty force of Megatron allowed them to complete the job in three days!