Over a million sewer blockages were cleared by the Johannesburg Water sewer teams on a jetting preventative programme across the city in the last financial year (2017/18) with a total of 147 182 of these sewer blockages occurring in the Midrand/Ivory Park area.
I spent yesterday morning with the community of Ivory Park along Nkosi Street where continuous sewage bursts are experienced.
A jetting truck was used to unblock the sewage blockage and a large jacket was found to be the cause of the sewer blockage.
I urge community members to assist Johannesburg Water to protect the City’s infrastructure. When the community reports problems to Johannesburg Water we can attend to it timeously.
In 2003 the entity procured three of the current fleet of 9 hydro jetting vehicles that are used to clean the sewer network. In the past year the programme has led to more blockages being cleared since its inception and addition to the fleet.
The sizes of the jetting vehicles vary from the smallest with a jetting tank of 4000 litres to the largest with a jetting tank of 12000 litres. The jetting vehicles operate using a high-pressure water pump, able to generate up to 120 bars of water pressure at a flow rate of 300l/minute. Depending on the nature of the blockage or the general condition of the network, different jetting nozzles are used.
The jetting nozzle is designed to propel the nozzle into the sewer pipe using rear facing water jets and have water jets in front as well to clear any blockages.
In areas where tree roots have grown into the sewer, root cutting nozzles are used which are rotated by the force of the water and then mechanically cut the tree roots from the inside of the sewer. The actual cause of the blockage is either then removed from the sewer by vacuum, or manually removed with a catch that is placed in the downstream manhole.
Annually, the blockage record is analyzed to determine areas/suburbs with a high blockage rate and based on that information the jetting truck will be deployed to those areas.
In the past where the preventative jetting has been done, the blockage rate would decrease.
But because there is a lot of vandalism and misuse of the sewer system, like where car tyres, vehicle engine locks, solid refuse, etc. are dumped into the sewer system, the blockage rate does not necessarily remain low.
Residents are encouraged to take care of their sewer infrastructure by not flushing or inserting foreign objects into the sewer network, which is ultimately their sewer network.
Cllr Nico de Jager
MMC for Environment and Infrastructure Services
City of Johannesburg
Media enquiries:
Cllr Nico de Jager
MMC: Environment and Infrastructure Services Department
083 899 2127
