Ideal treatment of laundry wastewater with ultrafiltration installations
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Scientific Article Ideal treatment of laundry wastewater with ultrafiltration installations published in "WRP" 07-08/2006 Treatment of very dirty work clothing also produces heavily polluted, oily/greasy wastewater. It is the aim of laundry wastewater treatment to reduce fresh water consumption and to minimise the volume of residuals. At the same time, adherence to the limit values according to appendix 55 of the General provisions on hydrocarbon, heavy metal and AOX contamination in wastewater must be guaranteed. For the treatment of laundry wastewater with a high percentage of blue cloth and footmats, EnviroChemie has developed a low-cost, easy-to-operate and robust technology, used in the standardised, modular Envopur Ufi NA ultrafiltration installations. An advantage of these ultrafiltration installations is their small footprint and low operating costs. The filtrate produced by the ultrafiltration installation can be directly used for prewash programmes or for mat wash, thus decreasing the specific fresh water consumption. The ultrafiltration installation is the first stage of a wastewater recycling plant within a recycling concept. Through expansion by a second membrane stage, an Envopur NFI NA nanofiltration stage, the wastewater can be recycled in a way that makes it suitable for use in the entire washing process. The modular addition of a nanofiltration installation is possible any time. As an option, a wastewater disinfection stage with ozone, UV, hydrogen peroxide or combinations thereof can be installed. An optional concentrate treatment stage from the Envopur product family facilitates an additional reduction of the volume of residuals by 50%. An advantage of the system solution presented is its modular construction, allowing any combination of the components according to the requirements. Wastewater treatment in laundries for working clothes The laundry wastewater load can vary considerably depending on the percentage of blue or white laundry and of mats. Below you can see the typical composition of wastewater coming from a laundry with high percentage of blue clothing and mats. Further you can see the accessible wastewater concentration values in the filtrate of the ultrafiltration installation and in the filtrate of a downstream nanofiltration installation. Laundry wastewater load Filtrate from Filtrate from Parameter Unit Raw water ultrafiltration nanofiltration Conduct. pS/cm approx. 3,000 approx. 3,500 500-1,000 Znmg/l<J0< 0.5< 0.01 Envopur wastewater treatment plant The wastewater from the washing process in the working clothes laundry is carried from the washing machines to a pump sump. There, special wastewater feed pumps are mounted, that use level control to carry the water to the wastewater stacking tanks via a sieving machine for lint removal.

A dynamic partnership - ENVKROWORLD The filtrate capacity of each module can be determined with a flow meter. The filtrate still contains large amounts of the tenside components that have not been consumed during the washing process and is carried into the recycling water storage tank or into the interim storage tank. Part of the filtrate can be reused for prewash or mat wash programmes. The other part undergoes a final control and is carried via a heat exchanger to the drain. If reuse of the wastewater as main washing water is desired, the wastewater must be further treated with...