Hartbeespoort Dam, South Africa

The Hartbeespoort Dam is located 37 km west of South Africa's capital city, Pretoria and is surrounded by a number of very affluent residential areas.  It is classified as hypertrophic and is heavily loaded with nutrients which have entered the dam due to runoff from fertilized fields and the inflow of sewage plant effluents from the northern suburbs of Johannesburg.  For most of the year, the dam is dominated by dense populations of cyanobacteria, or blue green algae.

One of the earliest Phoslock trials was undertaken on a 2.5 hectare man-made bay at K'shani Lake Lodge, a housing development on the western side of the dam.  The site had an average depth of 3m and was connected to the main dam through an opening of 8m.  This was blocked off with floating logs and a tarpaulin weighed down with chains.  A further area was blocked off in a similar manner within the test site to serve as an untreated control area.

Six tonnes of Phoslock were applied to the bay in January 2006 by the South African licensees and the treated and control sites were monitored over the following 12 months by the University of Pretoria.  The trial resulted in a clear and sustained reduction in filterable reactive phosphorus in the treated area over the course of the 12 months in comparison to the control area.  Full details of the trial are available in the downloadable report.

Seperating from main dam by screenApplication equipment at HartbeespoortPhoslock application at Hartbeespoort

Downloadable documents

Report December 2006 (pdf icon English 287Kb)