Clearedge is a specialist biological wastewater treatment company based in Durban, South Africa. Our expertise extends beyond sewage package plants, to potable water treatment and industrial water treatment.
We are registered with the South African Council of Natural Scientific Professions (SACNASP) as well as the Water Institute of Southern Africa.
We offer proven, low-maintenance sewage package plants to treat wastewater to acceptable standards, and filtration systems to treat potable water to Class 0/Blue standard. Using patented technology, our sewage treatment plants remove harmful organics from the waste, neutralising Ammonia and reducing Biological Oxygen Demand levels to acceptable environmental standards. Our systems are designed and signed-off by registered process engineers so you have the peace of mind that the system will work as intended.
At the heart of all biological treatment systems is the aeration system and this is where Clearedge has the 'edge' over other systems. Our patented, zero-maintenance Whale Tooth™ aerators offer superior dissolution of oxygen into water compared to conventional blower & diffuser systems. Read more about the Whale Tooth™ advantage here.
Our Water Security solutions provide our clients with reliable access to good quality water . Clean, sterile drinking water can be achieved from alternative sources - rain water, boreholes, rivers and dams - using our compact water filtration systems. Read more about Water Security here.
The company was established in 2000 by Mat Carlisle who has over 25 years industry experience. Mat is still actively involved in system design and the day-to-day operations.
Our core offering is Wastewater Treatment, although we offer a range of services from System Design, Consulting, Manufacturing & Installation, to Maintenance Contracts. Our experienced design team will customise each system to meet the specific discharge standard required.
OUR STP PROCESS
Clearedge's Sewage Treatment Plant (STP) system utilises Anaerobic and Aerobic processes. Our Aerobic section makes use of Fixed-film Aeration (as opposed to Activated Sludge).
Read more about Fixed-Film Aeration vs. Activated Sludge here.
Our system is comprised of 4 sections:
1. PRE-TREATMENT / ANAEROBIC SECTION
The pre-treatment section is comprised of a septic tank. The sections of the tanks are connected with pipes configured in such a way as to prevent solids from flowing between the sections. The Anaerobic section has a minimum retention time of 24 hours. A minimum of 30% reduction in Chemical Oxygen Demand (COD) is achieved in this section. Effluent is transferred via gravity or submersible pumps (depending on the site) into the first bioreactor.
2. AEROBIC SECTION
The Aerobic section is comprised of bioreactors. These are made up tanks (or chambers) containing a fixed-film media together with the aeration system which makes use of Clearedge’s patented Whaletooth™ technology. COD is further reduced by 90% in this section.
3. SLUDGE MANAGEMENT
Our fixed film system produces very little sludge – this is a feature of fixed film systems but is also dependent on correct loading and good aeration. Sludge collects in the clarifier from where it is returned to the head of the septic tank for decomposition. This function is automated. It may be necessary to de-sludge the head of the septic tank from time to time (every 3 – 5 years in our experience). A honey sucker can be used for this and the sludge buried, dried in sludge bags, or taken to the local sewage treatment works for disposal.
Disinfection is by Chlorine which is dispensed between the clarifier and the Contact Tank. There are various dispensing options available depending on the requirements. Treated effluent is discharged out of the contact tank into the environment.