Waste not only often smells bad, sometimes its bioaerosols can even be dangerous. With the innovative CLEAN Option filter system, ZÖLLER-KIPPER has averted this risk.

Waste has always stunk. It smells of butyric acid and rotten vegetables, of rotten eggs, ammonia and acetic acid, sweetly of decomposition and musty when mould is also involved. In short: everything that bacteria and organic chemistry can produce in the absence of air. An olfactory explosive gas mixture… No wonder that waste disposal has never been one of the most popular jobs.
A large proportion of the so-called bioaerosols, as the gas mixture is technically known, simply smells unpleasant. However, the situation is different for the fine dust, mould spores or microorganisms such as viruses that it may contain. Inhaled in high concentrations, these can actually make you ill.

Decades of research
As early as 1994, the German Social Accident Insurance Institution for the public sector in North Rhine-Westphalia and its predecessor institutions carried out extensive investigations and measurements to determine the exposure of refuse workers to mould fungi and ways of reducing it. The impetus for this was a case of respiratory disease in a refuse worker, which was thought to have been caused by his job – a case that caused considerable concern among experts and the general public alike. Many investigations and measurements followed to determine the exposure to mould fungi and ways to reduce it. The results of the investigations and the recommendations derived from them were incorporated into the TRBA 213 ‘Waste Collection – Protective Measures’ in 2005. However, follow-up investigations in 2013 and 2014 showed that there is still plenty of room for improvement in terms of clean air.

Innovation: an air curtain protects against pollutants
In 2015, the Closed Substance Cycle Waste Management Act followed, according to which biowaste is to be collected separately. And it was also in 2015 that the large number of studies and papers on the subject encouraged the engineers at ZÖLLER-KIPPER to take a closer look at the topic. ‘In the past, there were odour control spray systems at the rear to ‘drown out’ odours and spray mist systems to bind dust. Furthermore, there were also simple extraction systems,’ explains Sascha Wucher, Product Manager at ZÖLLER-KIPPER.
But only a combination of an air curtain and a 3-stage filtration proved to be really effective. The engineers spent about a year working on it, repeatedly simulating the spread of bioaerosols in the air using theatrical fog. This resulted in scenes reminiscent of a movie, with thick plumes of fog billowing out of the back of the waste refuse vehicle, spreading and eventually enveloping everything…

Effective with the DEKRA seal of quality
‘The tests were very informative in helping us to understand the interaction between the extraction system and the air curtain,’ says Sascha Wucher. ’After a year of development, we were able to present the first prototype at IFAT in 2016.’
This is how the system works: ‘At the rear of the vehicle, the environment is practically sealed off to the rear, because CLEAN Option works like an air curtain that counteracts the escape of bioaerosols from the vehicle. CLEAN Option consists of filter elements for coarse and fine dust, as well as an activated carbon element to eliminate odours. A radial fan blows outside air at an air pressure of up to 800 Pascals into the rear part of the vehicle, creating a slight vacuum here, i.e. directly in the refuse collector’s working area. Before being released into the environment, the extracted air is cleaned by a cyclone pre-filter to separate coarse dust and an integrated element made of fine dust filter with activated carbon. The system’s functionality was verified in extensive tests. The result is a significant reduction of harmful air in the garbage collectors‘ workspace.’ In a 16-page report, DEKRA also certifies the effectiveness of the air filter. Since then, garbage collectors and passers-by alike can breathe a sigh of relief.