Abstract: The technical feasibility of central processing of home laundry is discussed. Prime locations for application of this concept would be large urban centers in both developed and developing regions of the world. The sustainability of such a process is dependent on reduction of water, chemical, and energy usage as compared to levels used in conventional laundering while maintaining cleaning performance for a wide and variable range of soils and stains. In this regard, results are reported for long-term pilot-scale studies in which consumer clothing was cleaned as individual loads using a commercial washing machine and a commercial heavy-duty liquid detergent. Pre-softened wash and rinse water were recycled using an optimized microfiltration process system. Reductions in water and detergent usage of 75% and 25%, respectively, were routinely achieved without negative effects on cleaning levels. The microfiltration process was key to effectively removing contaminants from water while allowing some reuse of detergent ingredients. A control system utilizing dynamic surface tension measurement was used to automatically adjust detergent dosage during the tests. Also, important secondary effects of water recycle were examined including dye transfer, bacteria removal, fabric strength, and the fate of bleach and fluorescent whitening agents. No negative secondary effects were observed despite the rather closed recycle loop. In general, microfiltration was found to be a useful technology for improving the economic and environmental viability of central processing of home laundry.
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