Page 339 - Fair, Geyer, and Okun's Water and wastewater engineering : water supply and wastewater removal

JWCL344_ch09_297-332.qxd 8/2/10 9:54 PM Page 299

9.2 Public Health Significance of Cross-Connections 299
Investigation revealed that the funeral home had been using a hydraulic aspirator to drain
fluids from the bodies of human “remains” as part of the embalming process. The aspirator
connected directly to the water supply system at a faucet located on a sink in the “prepara-
tion” (embalming) room. Water flow through the aspirator created suction that was utilized to
draw body fluids through a hose and needle attached to the suction side of the aspirator.
The contamination of the funeral home potable water supply was caused by a combi-
nation of low water pressure in conjunction with the simultaneous use of the aspirator.
Instead of the body fluids flowing into the sanitary drain, they were drawn in the opposite
direction—into the potable water supply of the funeral home (see Fig. 9.1).

9.2.2 Sodium Hydroxide in the Water Main
A resident of a small town in Alabama jumped in the shower at 5 a.m. one morning, and
when he got out his body was covered with tiny blisters. “The more I rubbed it, the worse
it got,” the 60-year-old resident said. “It looked like someone took a blow torch and
singed me.”
He and several other residents received medical treatment at the emergency room of
the local hospital after the public water system was contaminated with sodium hydroxide,
a strong caustic solution.

Normal operation Open
positive supply pressure potable water

Closed

Cold

Negative supply Open Hot
pressure
Closed

“Hydro”
Cold aspirator

Hot

Reverse flow through
aspirator due to Body fluids
back siphonage

Figure 9.1 Reverse Flow through Aspirator Due to Backsiphonage