LCA study and environmental benefits for low temperature disinfection process in commercial laundry

Background, Aims and Scope. This study aims to compare the energy requirements and potential environmental impacts associated with three different commercial laundry processes for washing microbiologically contaminated hospital and care home laundry. Thermal disinfection relies mainly on a 90 degrees C washing temperature and hydrogen peroxide, while the chernothermal disinfection uses a combination of chemicals (mainly peracetic acid) and 70 degrees C washing temperature. The chemical disinfection process relies on a combination of chemicals used at 40 degrees C. Currently, chernothermal processes are the most commonly used in professional laundries. Traditional chemical processes are uncommon due to drawbacks of longer residence time and high chemical requirements. However, the innovative Sterisan chemical process based on plithalimidoperoxyhexanoic acid (PAP) which is the key subject of this Life Cycle Assessment - was designed to overcome these technical limitations. Methods. This study is based on a screening Life Cycle Assessment (LCA) prepared in 2002 by Oko-Institut (Germany), which was carried out following the requirements of the ISO 14040 series standards. It includes energy resource consumption, water resource consumption, climate change, eutrophication and acidification potential as relevant environmental indicators. In 2004/2005, the study was further updated and broadened to include the aquatic eco-toxicity potential, photochemical oxidant formation and ozone depletion potential in order to represent the environmental burdens associated with the chemicals used. Based on available data, the system boundaries include detergent manufacturing, the professional wash process, waste water treatment, but excluding the laundry finishing process. The selected functional unit was 1 kg washed hygiene laundry. Results and Discussion. The LCA indicates that the Sterisan chemical process has a lower potential environmental impact than thermal or chernothermal treatment for six out of seven key indicators. This includes a 55% lower energy and a 46% lower water consumption. The global warming potential and acidification potential are approximately halved, while the photochemical oxidant formation potential and eutrophication potential are almost reduced to one third. By contrast, for the aquatic eco-toxicity, the thermal- and chernothermal processes have an approximately 17-fold lower impact. The worse aquatic toxicity score for the Sterisan process is mainly caused by a solvent component in the formulation. Conclusion. The comparison of the thermal, chernothermal and Sterisan commercial laundry processes shows that the Sterisan process allows for very substantial reductions in energy and water consumption, as well as significant reductions in climate change, photochemical oxidant formation potential, air acidification potential and eutrophication potential. Yet, Sterisan has a clear disadvantage with regards to aquatic eco-toxicity potential. Recommendation and Perspective. Based on a current hygiene laundry volume of approx. 584,000 tons of linen washed per year by commercial laundries in Germany, a full substitution of the market to the Sterisan process could potentially allow a primary energy saving of similar to 750,000 GJ/year (roughly equivalent to the residential primary energy consumption of 23,500 German citizens or the overall energy demand of approx. 6,000 German citizens). In terms of improvements to the respective processes, the chernothermal and thermal process could benefit from a reduction of water volume, and change of detergent composition to reduce the eutrophication potential. As the washing temperature is an essential factor, only slight improvements for the energy consumption indicator can be obtained, e.g. by choosing green electricity and reducing the amount of water to be heated. The Sterisan process could be improved by lowering the solvent use, although for perspective, the current aquatic eco-toxicity score of the Sterisan process is still lower than that of a typical domestic laundry product.