Victoria Bight: Mother Nature's Sewage Treatment Plant?

Edward E. IshiguroDepartment of Biochemistry &

MicrobiologyUniversity of Victoria

My Goals

• What are the objectives of conventional sewage treatment and how are these objectives achieved?

• What is known for sure about the Victoria process?

• Why should we treat our sewage?

The Victoria sewage treatment system

The Victoria sewage treatment system

What is sewage?• Includes everything that goes down all of the drains in your

home

• What you can see in sewage is not all that is really there

– i.e., perhaps as much as 70% of the organic matter gets past the screening process (soluble material and small particles, much of which is not visible)

The main objectives of conventional sewage

treatment

• Eliminate fecal-borne microbial pathogens (e.g., chlorination)

• Decompose all complex organic matter to simpler chemicals (composting)

Conventional sewage treatment

Summary

• Secondary sewage treatment is the minimum requirement for satisfying the two main objectives of sewage treatment

• The claim is that the Victoria treatment is as good as any conventional secondary treatment system.

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What is known for sure about the Victoria process: more take-home lessons• We release large amounts of

organic matter into the ocean.

• Contrary to claims, there are no data that directly demonstrate the quick and effective decomposition of this matter because there are no methods for obtaining such data.

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Scenario 1: our sewage treatment is not working

• Cold temperature may have negative effect on metabolic rate of bacteria

• If true, then where is the undigested organic material in sewage accumulating?

Scenario 2: it is working well

• Then, how much fertilizer can the ocean take?

• Too much may be harmful

150 'dead zones' counted in oceans

U.N. report warns of nitrogen runoff killing fisheries

MSNBC staff and news service reportsUpdated: 1:12 p.m. ET March 29, 2004

----------------------------------------------------------------• Lifeless, oxygen-depleted regions

• Caused by release of excessive nutrients, e.g., from farm fertilizer, sewage, etc.

• U.N.’s top emerging ecological challenge

– Total of 150 zones covering 27,000 square miles

Sewage treatment: a characteristic associated with

civilization• United Nations estimates 2.4 billion people

lack access to basic sanitation, including sewage treatment

– We are not included in this number!

• United Nations Millennium Declaration (2000) proposes to cut this number by half by 2015