In situ cleaning system for fouled membranes
US5403479A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1993 |
| Grant date | Apr 4, 1995 |
| Priority date | — |
| Expiry date | Dec 20, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2321/168
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method and cleaning system is disclosed for cleaning the outer surface of a fouled microfiltration (MF) or ultrafiltration (UF) semipermeable hollow fiber membrane after its initial stable transmembrane flux has been decreased to an unacceptably low level. The method is specifically applicable to any fiber used to withdraw purified water from dirty water, particularly water containing organic matter including beneficial bacteria and/or undesirable inorganic salts, where the viability of the bacteria population is to be maintained. The membrane is cleaned by flowing a cleaning fluid, preferably a biocidal oxidative electrolyte having an oxidizing anion and an associated cation through the clean, permeate-side of the membrane, at low pressure no more than the bubble pressure breakthrough, usually <300 kPa (30 psig) for a MF or UF fiber. Such low pressure is sufficient to diffuse the electrolyte through both, the pores of the membrane and a fouling film which typically includes a biofilm accumulated on the fibers' outer surface, but not enough electrolyte flows through the membrane to kill numerically more than 20% of the living bacteria in the dirty water. This limitation can be me…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.