Johannesburg Water sewer teams cleared over a million sewer blockages on a jetting preventative programme across City of Johannesburg.
Environment and Infrastructure MMC Nico de Jager said it is with a total of 147 182 of sewer blockages occurring in the Midrand or Ivory Park. Jager said he spent some time with the community of Ivory Park along Nkosi Street, where continuous sewage bursts are experienced.
“Jetting truck was used to unblock the sewage blockage and a large jacket was found as a cause of the sewer blockage. Community members should assist Johannesburg Water to protect City’s infrastructure. When community reports problems to Johannesburg Water, we can attend it immediately”, he said.
In 2003, the entity procured three of the current fleet of 9 hydro jetting vehicles used to clean the sewer network. The past year, the programme has led to more blockages being cleared since its inception and addition to the fleet.
Jager said sizes of the vehicles are differentiated from the smallest with a jetting tank of 4000 litres to the largest with a jetting tank of 12 000 litres.
“The jetting vehicles operate using a high-pressure water pump which is able to generate up to 120 bars of water pressure, at a flow rate of 300l per minute. Different jetting nozzles are used depending on the nature of blockage or the general condition of the network. Jetting nozzle is designed to propel nozzle into the sewer pipe, using rear facing water jets and have water jets in front as well as to clear any blockages”, he said.
Places where tree roots have grown into the sewer, root cutting nozzles are used and are rotated by the force of water. Then mechanically cut the tree roots from the inside of the sewer. Jager added that the actual cause of blockage is either then removed from the sewer by vacuum or manually removed with a catch that is placed in the downstream manhole.
“The blockage record is analysed to determine areas or suburbs with a high blockage rate annually. It is also based on the information the jetting truck will be deployed to those areas. The blockage rate decrease where preventative jetting has been done”, said Jager.
Though there is a lot of vandalism and misuse of sewer system like where car tyres, vehicle engine locks, and solid refuse are dumped into sewer system, the blockage rate does not necessarily remain low.
Jager encouraged residents to take care of their sewer infrastructure by not flushing or inserting foreign objects into the sewer network. He added that ultimately the sewer network belongs to the community.
