Jun 20
waste treatment


Dolphin Bay has held a highly constructive meeting with the relevant hazardous waste disposal authority, to ensure that CCA waste disposal methods are affordable and achievable for our customers.

This follows the authority’s rejection of some of our customers’ waste samples for allegedly containing unacceptably high levels of sulphates. As a result, the waste would need encapsulation.

Encapsulation would be prohibitively expensive, difficult and, we believe, unnecessary. Dolphin Bay approached the authority in question to set up a meeting. We believed these sulphates had been introduced during the neutralisation process, as CCA itself does not contain such high sulphates levels. CCA is normally treated with ferro-sulphate and only this could be the source of the high levels.

“It was a very constructive meeting, conducted in an atmosphere of co-operation,” said Braam Rust, who attended on behalf of Dolphin Bay. “The authority took trouble to help us and come up with solutions.”


“Our industry might need to find a new way, other than ferro-sulphate, to treat CCA waste samples.” 


It was proposed that instead of encapsulation, CCA waste containing high leachate levels could be made into bricks using a cement mixture.

Further CCA waste samples will be taken from those customers whose waste reportedly contained high sulphate levels. These samples will be submitted to a third-party laboratory for testing before any treatment takes place at the disposal site. This third-party laboratory will determine whether the CCA samples contained sulphates before being submitted, or whether they were introduced during treatment at the disposal site.

Hazardous waste has come under increasing scrutiny by the authorities in the past year as the government enforces the principles of “reduce, re-use and recycle”. These days only CCA samples with marginal allowances of leachable concentrates are passing the tests required for disposal.

The waste disposal organisation conducts a series of tests on each waste sample submitted and has rejected many samples of CCA waste this year. The cases of waste reportedly containing sulphates is the most recent of such development.

Lime and ferro-sulphate have long been used in our industry, and by the waste disposal authorities, to stabilise the active components in CCA waste. “However, it is evident that the use of ferro-sulphates is becoming an obstacle in the process of waste disposal,” observed Bertus. “Our industry might need to find a new way, other than ferro-sulphate, to treat CCA waste samples.

“We are taking a proactive approach and, as a first step, we are conducting the same leach tests in our laboratory, using the same criteria as those conducted by the authorities. We have built equipment to do this, according to the relevant SANS requirements.

“The reportedly high sulphate levels are yet another indication of the growing complexity of the CCA waste disposal process,” Bertus added. “We strongly advise all our customers to be aware of the challenges faced by our industry with regards to contaminated waste, and to do what is possible to reduce waste.

“At the same time, our laboratory is investigating new processes to treat CCA waste. We will keep our customers informed about our progress.”