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Sewer System Bears the Cost of Flushed Wipes

 

 
The desire for greater convenience in our lives has made nonwoven wipes a multi-billion dollar industry. Wipes are available for just about any bathroom cleaning task – wiping, removing makeup, changing a baby, washing the counter or cleaning the floor. The industry continues to grow and so do the problems in our sewer system as more of these wipes make their way down the toilet.
 
“Nonwoven wipes are changing the characteristics of the waste stream,” explains Wendy Barrott, the Detroit Water and Sewerage Department’s (DWSD) Wastewater Treatment Plant General Manager. “The equipment in our sewer system and at the treatment plant was not designed to handle this.”
 
The very characteristic that makes wipes so attractive from a cleaning standpoint – wet strength – makes them a nightmare to clean up in the sewer system. Wipes retain their strength, attach to other wipes and catch on equipment in ropy chains. Wipes also form clumps that grow into hard masses creating blockages and damaging equipment. Sewers need to be cleaned with high pressure water jet equipment to break apart these obstructions, and pumps have to be pulled so messy clumps can be detangled and cut away.
 
Communities throughout the country are becoming increasingly frustrated as wipes create havoc in their sewer pipes, pumping and lift stations and wastewater treatment plants (WWTPs). Maintenance costs are rising due to increased labor to remove the wipes. Some communities are switching to different style pumps but the wipes just travel further downstream and eventually have to be dealt with at the WWTP. Awareness and publicity around the problem has prompted clean water professionals and wipe manufacturers to come together to try and address the problem through voluntary and ISO (International Standards Organization) standards. Change is needed on many fronts.
 
Toilets or Trash Cans?
Baby wipes have been on the market since the late 1970s but people didn’t start flushing these and other wipes until “flushables” hit the shelves. Personal cleaning wipes have grown into a big adult market changing consumer flushing habits.
 
Field studies undertaken by associations for clean water professionals and the nonwoven industry in 2011 and 2012 revealed that 40% of materials trapped on pump station inlet screens were nonwoven wipes. Baby wipes represented the largest percentage at 18%, followed by household wipes at 14% and flushable wipes at 8%.
 
“We need to look at both the design and use of wipes in addressing this problem,” explains Rob Villée, an expert on the US Technical Advisory to develop ISO standards for flushable wipes and a leader with the Water Environment Federation advocating for member utilities throughout the country. “Many wipes not designed as ‘flushable’ are being flushed. Point of sale data shows that 40% to 50% of customers who buy baby wipes don’t have babies. If a wipe becomes contaminated by use, it is likely to be flushed.”
 
A variety of jar and slosh tests have revealed that most of these wipes do not break apart. While some manufacturers are developing new technology that breaks apart, today’s definition of “flushable” does not mean it is safe for the sewer system.
 
Better plumbing has also impacted our flushing habits. “Low flow toilets are more powerful and capable of flushing more than older models,” continues Villée. “Wipes easily make it out of the house and consumers don’t understand where they go.”
 

 
Nonwoven wipes are creating problems throughout the collection system tributary to the Detroit WWTP as well as at the plant itself. Wipes make their way through screens and get caught in individual treatment trains requiring extra cleaning by plant staff.
 
 
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