William Angliss Institute

Certificate IV in Food Technology

 

Lesson Two

Waste Water Treatment

 

Solids

Plastics, Metals, sand, clay

Wood; Plant mater, cars, bodies etc.

Biodegradable Soluble material

Carbohydrates

Petroleum

Other organic compounds

Non- Biodegradable soluble material

Recalcitrant molecules

Detergents

Dioxans

Heavy Metals

Anions

Treatment Processes

Read about sewage treatmet systems on the Seven Trent Web page

http://www.severn-trent.com/schools/sewage.htm

Primary Treatment

 

 

Secondary Treatment

PRODUCING INOCUOUS PRODUCTS

CO2, H2O, NO2-, SO4=

Producing smelly products

Ammonia, H2S, CH4

 

Eg:

 

 

Large diesel/gas engines burn mainly methane and drive generators

It si possible to make enough electricity to supply all the needs of the treatment plants and still have enough left over to sell to the grid.

If all the sewage and solid waste from a city was digested anaerobically there would be enough methane to generate all the electrical needs of the city. The burning of the methane produces CO2, which is a green house gas. But the total CO2 produced is no more than any other method of waste disposal. All organic mater ends up as CO2 wether it is digested under ground, under sea, or in an aerated tank or lagoon.

If waste were used to generate electricity we would not need to burn the fossil fuels like coal and oil that we now use. This means wed could halve the present production of CO2 from power and waste treatment.

 

Home Work:

Read the following hyperlink about treating wastewater:
Small town sewage treatment

Outline over all process of wastewater treatment

Examine the Yarra Valley Water Web Page by clicking on the hyperlink below. When finished return here by clicking on your "Back Button"

Yarra Valley Water http://www.yvw.com.au/corporate/infopubs/sewage/sewageTreatment.html

 

Can you describe the changes that occur during Primary, Secondary and Tertiary Treatment of sewage?

Consider the option of "direct chemical oxidation" to reduce B.O.D. by reading the next hyperlink:

The Direct Chemical Oxidation Option

 Is this Secondary or tertiary?

 Go to Lesson One

 Go to Lesson Three

Go to Lesson List

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Prepared by Barry Brazier

 


William Angliss Institute

Nutrition Australia

Australian Nutrition Foundation

AIFST

Hospitality Association

Barry Brazier

Hospitality Network

About Melbourne