Wednesday 26 September 2012

Sewage Treatment Problems: Non-flushable wipes

Robert Villee , Executive Director of Plainfield Area Regional Sewerage and Chairman of the Water Environment Federation Collection Systems Committee highlighted the problems created by non-flushables in waste water collection and pumping stations. Any wipe not dispersing quickly and completely should not be regarded as flushable.  Those that don’t disperse do clog pumping stations and check valves and these blockages are happening increasingly often.  Solutions are being sought on several levels:

  • ·         Fit bar-screens to remove debris before pumping
  • ·         Encourage wipe manufacturers to improve labeling of non flushables
  • ·         Educate consumers who seem to feel that anything disposable is flushable
  • ·         Encourage the pump manufacturers to develop better pumps.
  •           A product labeled “Flushable” should disperse, like 2-ply toilet paper, in under 2 minutes and should be fully dispersed before it leaves the household pipes.  

    However a field study at Portland Maine obtained results from the visual sorting of screen-blocking  waste that suggested nonwoven wipes were not the main culprit:
  • ·         42% of the screened waste was paper towel from public washrooms (ladies use them to cover seats).
  • ·         25% were baby-wipes
  • ·         17% were sanitary protection products
  • ·         8% were flushable wipes.
So 92% of the problem should not have entered the toilet system in the first place. 

In a second field test, an attempt was made to block the pump by feeding baby wipes into inlet.  The pump refused to clog.

The paper towel problem should be addressed by removing them from ladies washrooms (use hot air driers), and these washrooms should also have a bin for the safe disposal of sanitary protection.  Baby Wipes should all be flushable but recognizing that this would be costly they should at least be labeled non-flushable much more prominently than at present. Consumer education should start in the maternity ward where non-flushable wipes are often presented to new mothers without their non-flushability being communicated.  Retailer’s displays of baby wipes should emphasize the “Don’t Flush” message.  Keep it as simple as possible: “If it’s not toilet tissue, don’t flush it”

(from a paper given at the INDA WOW Conference, Chicago, June 2012)

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