Image: European Cleaning Journal

Chemical-free cleaning is becoming more popular all the time as customers increasingly seek sustainable solutions, writes Ann Laffeaty. But are there still some situations in which only a chemical will do?

Chemical-free cleaning is a growing trend. An increasing number of companies are offering systems that use alternatives such as steam, deionised water, UV light, microfibre or water at high pressure in place of detergents or disinfectants.

The aim is to reduce the impact of cleaning on public health and the environment. But are there any cases in which a chemical-free solution would simply not be up to the job?

Car cleaning is one task where chemicals usually provide a better performance according to Nilfisk product management director Andrew Caddick. “Traffic pollution can be very sticky,” he said. “Chemical products also tend to be required for cleaning surfaces and units in the food industry and in the agricultural sector.”

The company is currently carrying out research into the optimal way of removing substances such as grease and oils from surfaces using a mixture of high pressure and chemicals. “During this process we have discovered cold water combined with chemicals can be just as effective as using hot water at high pressure,” he said.

Alternatives to chemicals are becoming increasingly popular in some sectors, according to Caddick. “Steam is becoming widely used in hospitals, for example, as well as in general cleaning,” he said. “I
also I know of an airline meals supplier that uses steam to clean its food preparation surfaces.

“But while steam will kill the bacteria, you also need to physically remove it – and this requires some vacuum action. And although steam works well in relatively small areas it would take days to clean, say, a large bottling plant in this way.”

Caddick recently visited a large brewery in Switzerland to observe the company’s cleaning techniques. “Despite the fairly draconian laws relating to chemical use in Switzerland, the brewery was using a mixture of detergents and high pressure to clean its bottling equipment,” he said. “There is still a huge requirement for chemicals in many sectors – particularly for disinfectant purposes. And there are also many applications where a detergent has to be a factor. Think about when you need to clean a substance such as egg or engine oil from your hands, for example: you will find that soap and a sponge works much more effectively than hot water alone.”

He adds that chemicals will penetrate beneath biofilms and break up the soiling. “Otherwise you would need to use hot water plus some mechanical action.

“I don’t think we have come up with a better solution than chemicals and at Nilfisk our detergent sales have remained constant. So the general aim is to make chemicals as efficient as possible in order to reduce consumption while also keeping up with legislation.”

Stricter legilsation

And legislation is becoming stricter all the time, says Caddick. “We need to look ahead and assess how the position is likely to change in the future,” he said. “In Europe there are particularly strict rules on what you can and can’t put into detergents. So it is up to the chemical manufacturers to come up with the best possible solutions – and it is up to us to put them into our product ranges.”

Kärcher trainer Sebastian Nann believes the majority of cleaning challenges can be tackled without the use of chemicals. “Most of the type of soiling found in administrative and office buildings is water soluble which means it can be removed without adding a cleaning agent,” he points out.

“To a certain degree, too, even oily and greasy stains may be removed using a high pressure washer or a steam cleaner operated at sufficiently high temperatures. This will also help to reduce the quantity of germs.

“However chemicals must be used instead when mineral-based stains are encountered or where a complete disinfection is required.”

He says the four factors crucial to cleaning success are mechanical effect, temperature, cleaning agent and time. “Generally it can be said that when a particularly high level of mechanical intervention is required – either due to the type of soiling or its concentration – the operation itself would cause damage to the surface or material to be cleaned,” he said. “So the use of cleaning agents would be recommended in these cases.”

According to Nann, customers are becoming increasingly environmentally-aware and this has been one of the driving factors behind a general reduction in the use of chemicals. “Of course there are other negative factors associated with the use of cleaning agents such as safety, cost and the complicated removal of dirt residues,” he said.

Healthcare environmental hygiene specialist Michael Rollins agrees there are some situations in which a chemical intervention is essential. “In healthcare for example, high-level disinfection is required on the type of reusable instruments that come into direct contact with the patient,” he said.

“Areas that have been contaminated by a known or suspected infection also require thorough chemical cleaning and disinfection.

“And in emergency situations where infectious outbreaks occur, any cleaning programme needs to include chemical decontamination. Here a hydrogen peroxide vapour is specified to eliminate residual environmental contamination of surfaces and the air.”

He says high level chemical disinfection is required in laboratories and in the pharmaceutical industry. “In the food industry too, regular surface cleaning and disinfection are essential to prevent the contamination of food,” he adds.

According to Rollins the trend towards chemical-free cleaning has become more pronounced over the past decade. “However, in the healthcare sector this trend is regularly interrupted by high-profile outbreaks of infections or viruses,” he said. “This leads to a return to safety and the intense chemical disinfection of all surfaces regardless of whether or not this process is needed.”

Neutralising odours

Chemical intervention is usually the best solution in closed environments and on less accessible surfaces such as sink drains and waste pipes, he says. “The biofilm build-up here will require aggressive chemical action to ‘dissolve’ or emulsify the residue in order to allow flush-cleaning,” said Rollins. “Biofilms are particularly challenging since mature biofilms will disperse bacteria to spread and contaminate the accessible environment.”

Neutralising odours is another example of the type of task that can be difficult to tackle without any chemical intervention, he says. “Again, odour is caused by bacteria that have been allowed to build up due to the porosity of the surface or the inaccessibility within drains and pipes,” he said.

“Also, certain microorganisms in spore form such as Clostridium difficile may be dispersed over a wide area via direct contact or via droplets in the air and will remain viable in the environment for extended periods of time. The standard procedure here would involve a robust cleaning programme of all exposed areas using chlorine at 1000 ppm.”

However, chemical use also has its drawbacks, he adds. “For example, it can negatively impact the short and long-term safety of the user and cause damage to surfaces, sensitivity to odour and potentially lead to antimicrobial resistance,” he said.

According to Rollins, one French healthcare facility has dramatically reduced its use of chemicals in response to all these negative factors. Toulon University Hospital has adopted a programme of microfibre cleaning using water alone in most parts of the building while chemical use is restricted to those areas where a suspected or confirmed infection has occurred.

“Research has evidenced satisfactory surface decontamination using water alone in its various forms such as dry steam vapour, ultrasonic immersion or in conjunction with a microfibre cloth,” he adds.

Chemicals are the only viable option for oil removal according to AM Services operations director Chris Condliff. “Extracting oil from stone or concrete surfaces always requires the use of chemicals to achieve a high quality finish,” he said. “And if the oil has been allowed to soak in, biochemical cleaning is required to attempt to draw the oil to the surface.”

The use of steam or water at high pressure might go some way towards removing the oil from the surface as well as from the pores of the stone, concedes Condliff. “However, this would leave unsightly residual staining,” he said. “Oil is quick to penetrate porous surfaces and where this has occurred it usually needs to be chemically dissolved so that the source of the stain can be drawn back out.”

Despite the limitations of non-chemical solutions, a growing number of customers are turning to them according to Condliff. “Some are worried about introducing new chemicals because – quite rightly – there is an obligation to monitor what is going down the drains and what is being used on site,” he said. “There has also been a decline in the number of customer requests for the use of substances such as hydrochloric acid over the past 10 years.

“People are now looking more towards bio-remedial products that are safer to use and cause less harm to the environment. However, while these chemicals may reduce the risk factor they are also more expensive to use. So in my opinion, there will always be a need for the use of certain chemicals.”

Michael Rollins agrees with this view, particularly where healthcare is concerned. “As new pathogens are detected we are reminded that we live in a global world where microorganisms can emerge and cause unexpected and severe outbreaks,” he said. “This typically results in a conservative approach to decontamination and a greater reliance on chemical disinfection.”

And Nilfisk’s Andrew Caddick concurs. “You can’t really get around it – detergents are part of the cleaning cycle,” he said.