Treatment of Waste

1
Treatment of Waste
2
Mary Mallon
3
The Walkerton E. coli outbreak in Drinking Water
Supply
May 12, 2000 Torrential downpour washes
bacteria from cattle manure into shallow town
well. May 30, 2000 Seven children dead.
1/2 of the town is sickened March 27,
2001. According to the court settlement, the
Province pays 15 mln for fixing towns water.
Commission to investigate the causes is
formed.
4
Lessons

• Walkerton not an exception.
• Lack of knowledge, complacent attitudes lead to
  serious problems
• Factors which contribute to outbreaks
• Multiple barrier failures. Source, treatment,
  distribution, monitoring and response
• Source
• Weather monitoring is important to predict
  potential problems. Heavy rainfall precedes most
  outbreaks.
• Water wells positioned next to potential sources
  of contamination.
• Poor geological conditions (shallow production
  zone)

Adapted from Hrudey et al., 2003. Water Science
and Technology 477-14
5
Lessons

• Walkerton not an exception.
• Lack of knowledge, complacent attitudes lead to
  serious problems
• Factors which contribute to outbreaks
• Multiple barrier failures. Source, treatment,
  distribution, monitoring and response
• Source
• Weather monitoring is important to predict
  potential problems. Heavy rainfall precedes most
  outbreaks.
• Water wells positioned next to potential sources
  of contamination.
• Poor geological conditions (shallow production
  zone)
• Treatment
• Balance between microbiological safety and health
  effects of decontamination byproducts
• Protozoan pathogens are resistance to chlorine
  disinfection
• UV disinfection may not be sufficient, especially
  without filtration

Adapted from Hrudey et al., 2003. Water Science
and Technology 477-14
6
Lessons (contd)

• Factors which contributed to the tragedy (contd)
• Distribution
• Main breaks and repair, fire events and
  depressurization,
• Cross contamination at connected private wells
  and cisterns
• Surface flooding and point-source contamination

Adapted from Hrudey et al., 2003. Water Science
and Technology 477-14
7
Lessons (contd)

• Factors which contributed to the tragedy (contd)
• Distribution
• Main breaks and repair, fire events and
  depressurization,
• Cross contamination at connected private wells
  and cisterns
• Surface flooding and point-source contamination
• Monitoring
• Limited number of samples (less than required
  13/mo)
• Sloppy sample processing. Treated water not
  routinely tested
• Chlorine residuals not measured daily as required

Adapted from Hrudey et al., 2003. Water Science
and Technology 477-14
8
Lessons (contd)

• Factors which contributed to the tragedy (contd)
• Distribution
• Main breaks and repair, fire events and
  depressurization,
• Cross contamination at connected private wells
  and cisterns
• Surface flooding and point-source contamination
• Monitoring
• Limited number of samples (less than required
  13/mo)
• Sloppy sample processing. Treated water not
  routinely tested
• Chlorine residuals not measured daily as required
• Response
• None
• Consumers continued to drink un-boiled water even
  after the advisory

Adapted from Hrudey et al., 2003. Water Science
and Technology 477-14
9
Waste Water Treatment

• Black water vs gray water
• Estimates of Organic Carbon
• Total organic carbon (TOC)
• Biochemical oxygen demand (BOD)
• Chemical oxygen demand (COD)
• BOD5 assay
• Amount of oxygen consumed by a mixed population
  of heterotrophic bacteria in the dark at 20C in 5
  days

10

• Why is it important to reduce bioavailable C?
• Is a coliform test a valid uniform predictor of
  the remaining pathogens? Why?

11
Waste Water Treatment
12
Composting and Pathogens
Average temperatures of properly composted wastes
A, B, C, D different of green/wet/dry waste
Vinneras et al., 2003
Lemunier et al., 2005
13
Survival of Pathogens in Composts
A, B, C, D different of green/wet/dry waste
Lemunier et al., 2005
14
Competition in compost?
Growth of L. monocytogenes (), E. coli (?), and
Salmonella serovar Enteritidis () in sterilized
mature compost (12 weeks of composting) from
pilot reactor D during storage at 25?C.
Lemunier et al., 2005
15
Drowning in disinfection bi-products?

• Microbiological safety vs DBP (disinfection
  by-products)
• Children swimmers have increased asthma instances
• 1.6-2 fold increase of bladder cancer in those
  swimming, showering in chlorinated water.
  Controls for other lifestyle factors?

Zwiener et al., 2007