2012-01-25: City launch solarbees and new bio-remediation on Bruma lake
25 January 2012
THE City of Johannesburg is rolling out some immediate steps to bring some immediate relief for hotels and other businesses located on Bruma Lake today.
These measures include the improvement of the aeration and the launch of three SolarBee circulators on 25 January 2012. This will assist the water’s natural ability to deal with the inflow of Biochemical Oxygen Demand.
The SolarBee is a unique floating solar powered, high flow circulator used in situations requiring improved oxygenation and circulation to address water quality problems. The circulators have been used in various dams across the USA with much success. This technology has also been installed with much success at Rietvlei Dam which is also suffering from sewage and other pollution flows into the dam.
The SolarBee draws up water and spreads it radially across the distribution dish in a near laminar and non-turbulent manner. It creates both horizontal and vertical mixing patterns and helps to eliminate thermal stratification and stagnation. It also assists with water quality by achieving increase in Dissolve Oxygen levels and improved sludge digestion. It has also been shown to be effective in reducing algae and odours by creating a slow but continuous movement of water.
The SolarBee requires no infrastructural changes, and can be operated day and night with a low voltage motor and on-board battery system for continuous, energy-efficient water quality improvement.
It is well established that circulation of lake water can have significant beneficial effects on the quality of the water.
Circulation of the water in Bruma Lake will not solve the pollution or odour problem, but it will go a long way towards temporarily alleviating it until the permanent remedial works can be implemented.
The SolarBees will also assist in bringing about more aerobic conditions which will support the current bio-remediation programme.
The City has also embarked on a new bio-remediation programme using a product called Eco-tabs to treat the lake. The dosing began at the end of December, with repeat dosing at regular intervals. Early indications are that the new product appears to be making an impact on the lake, with water clarity improved, reduced odours, and the sludge layer beginning to show signs of reduction in certain areas where it was previously exposed.
The City is also implementing various upstream measures to assist with treating the water before it enters the lake. One such measure is the reinstatement of the Queens wetland upstream of the lake, to enable it to perform its natural function as a bio-filter. The litter trap upstream in Bezuidenhout Park continues to trap approximately 60 tons of waste and debris per annum. This is being supplemented by other litter trapping devices such as litter baskets which will shortly be installed at key storm water outlets, and litter booms to prevent litter from washing over the lake.
The City of Johannesburg has undertaken various interventions to address the problems of silt, litter and pollution as well as to develop a plan for sustainable restoration and rehabilitation of the lake.
The long term plan includes the re-shaping of the lake basin and the reclamation and reinstatement of a grassed channel with parkland on either side of the lake, returning the area to a normal watercourse and reconnecting the upstream and downstream river reaches.
ENDS
For more information contact:
Nthatisi Modingoane
Deputy Director Communications Unit
City of Johannesburg Public Liaison Department
Tel: (011) 407 – 7354
Cell: 082 467 9228
E-mail: nthatisem@joburg.org.za
