Black Smoke Emissions and Soot Deposits From Nestlé in Mossel Bay explained

Community members lodged their concerns on Facebook regarding black smoke emissions and soot deposits emanating from Nestle, Mossel Bay.

The Garden Route District Municipality has become aware of these complaints via the Mossel Bay Municipality. In terms of current Air Quality legislation, we are responsible for Industrial Listed Activities (large industries such as PetroSA) and Controlled Emitters (boilers between 10MW and 50 MW heat input). One of the Nestle boilers is within the ambit of a controlled emitter, namely one of their coal-fired boilers. We arranged a site visit at Nestle on Wednesday 20 March 2019 and invited the air quality officers of Mossel Bay Municipality to join the site inspection.

The photo taken of the boiler stack (as posted on social media) has no reference to the precise date and time captured, therefore making it difficult to pinpoint a specific plant upset.  It must be noted that soot blowing must be done as routine maintenance on any coal-fired boiler. Soot blowing is a process whereby steam is blown under high pressure on the internal furnace tubes of a boiler during combustion to prevent plugging of the gas passes and maintain boiler efficiency. Air Quality legislation allows for this process, for normally 10-14 minutes within an 8-hour production cycle.  Black smoke emissions during small boiler start-up are also permitted but limited to a period of twenty (20) minutes during the start-up process (as per Nestlé’s controlled emitter authorization). Therefore it will happen about 3 times within 24 hours. It might, therefore, happen that visible smoke is eminent during these soot blowing episodes. It may however not a period exceed longer than 10-14 minutes. Nestle commissioned 3 multi-cyclone grid arrestors on their boilers to the value of R7million. A Multi cyclone grid arrestor is a mitigation device to capture the particulates in a gas stream before it is emitted through the stack. Since these grid arrestors were installed recently, the visible emissions from the Nestle stacks have improved significantly.

The grid arrestors will also ensure that the emissions are within the minimum emissions standards set for coal-fired boilers. We requested Nestle to independently test their boiler emissions in order for us to determine compliance with their Controlled Emitter Registration. The milk powder incident that was mentioned took place during June/ July 2018. Since then, no milk powder blow-out took place again. Nestle wants to prevent such blowouts at all cost as this is actually a loss of product to the value of R50/ kg. We also requested them to inform the authorities on any plant upsets, so that we at least can inform the public if such events took place.

We are also going to conduct ambient particulate matter monitoring at the Nestle site, and we will be communicating to the affected parties in order to place our monitor at their respective sites as well. This will give us a clear indication if the South African ambient limits for particulate matter are indeed exceeded. It must, however, be noted that there are more industries that could give rise to dust emissions in the same location as the Nestle plant. It is also noteworthy that there is a permanent ambient emissions monitoring station in Mossel Bay and that the results of the station are well within the SA ambient emissions standards. That said, we will definitely intervene if exceedances occur.

The public is also welcome to contact the District Air Quality office for any applicable air quality complaint under our jurisdiction. The office number is 044-693 0006 during normal office hours.

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