Sewage Wastes

Question 1

What does sewage waste comprise of? (8)

Answer 1

Complex Addition
Industrial / Human wastes
Suspended Solids
Pathogens
Heavy metals
Nutrients
Endocrine disrupting systems
Oxygen Demand

Question 2

What are the four ways in which sewage can reach the coastal enviroment?

Answer 2

Coastal Outfalls
Combined sewer outflows
cruise ships
recreations vessels

Question 3

What issues are caused because of sewage?

Answer 3

Direct environmental effects
destruction of habitat
aesthetic pollution
risks to human health
socioeconomic

Question 4

Explain the effects of aesthetic pollution

Answer 4

The can have large effect on the tourism industry as no one wants to be swimming where there is poop, sewage debris can also be washed back inland and be caught on the swash / backwash cycle causing an issue for surfers (surfers against sewage)

Question 5

What is the BOD

Answer 5

This is the breaking down of organic compounds by bacteria, which use dissolved oxygen in the process, thus taking oxygen out of the marine system

Question 6

What occurs at the BOD increases (on a graph)

Answer 6

The dissolved oxygen content decreases, it is the direct opposite curve of the BOD increase.

Question 7

Give an example of an Acute Pollution event and some facts

Answer 7

Thames 2005 - There were 125 days where DO was less that 30%. Then during 2011 there was a major release of pollutants and 3000 fish died :(

Question 8

What is the impact of chronic pollution on the marine environment

Answer 8

If the area becomes grossly polluted the it is unsuitable for all macro fauna organisms and can only be occupied by a small number of species. It goes from= Gross Poll - Poll - Transitional - Normal

Question 9

What is the effect on Coral reefs

Answer 9

As nutrient concentration in the reef rises then eutropfication can occur which means the % cover decreases

Question 10

How much of global sewage is treated?

Answer 10

<10%

Question 11

What are the five stages in sewage treatment works (including the pre and post stages)

Answer 11

1. Screening
2. Primary
3. Secondary
4. Tertiary
5. UV / Chorlification

Question 12

What occurs in the screening process?

Answer 12

This is the removal of large objects and grit, to allow the rest of the plant to function and prevent blockage

Question 13

What occurs in primary treatment

Answer 13

Settlement tanks, removal of fine solids (some bacteria) to form sludge

Question 14

What occurs in secondary treatment

Answer 14

Biochemical degradation, through air-rating the tanks and introducing “good bacteria” which remove viruses, dissolved organics, and nutrients phosphate and nitrogen

Question 15

What happens in tertiary treatment

Answer 15

further settlement and removal of sludge, removal of more bacteria.

Question 16

What can be the last stage in sewage treatment

Answer 16

UV light which kills anything living left, or that addition of chemicals such as chlorine, but these can be just as bad for the final receptor

Question 17

What is sewage sludge?

Answer 17

semi-solid material that is left over from sewage treatment works

Question 18

What was the former practice for sewage sludge disposal

Answer 18

Offshore dumping, UK had 15 registered sites. But in 1999 UK, 1988 US bans came into place to prevent dumping

Question 19

How is sludge disposed of now?

Answer 19

Landfill

Incineration (for bio-gas production)

Question 20

What is sludge reused nowadays?

Answer 20

Agriculture
forestry
land reclamation

Question 21

Long vs short outflows, BOSTON example, talk through it

Answer 21

The new longer outfall will mean there is a % percent effluence seen closer insure, where as the current one the % seen is higher. Even in summer when its a lot worse

Question 22

Give three examples of new sea outfalls with their lengths

Answer 22

Brighton - 2.5 km
Sussex - unknown
Newport - 2.5 km

Question 23

Talk through the Lodz example

Answer 23

This is an example of a sustainable sewage management and treatment, the sludge is used in the formation of willow plantations, which is then converted to biofuel, and wetland construction occurs from purified sewage which then protects from storm events

Question 24

What may be public concerns with regards to sewage efflence

Answer 24

Surfers against sewage
Health protection authority
Blue flags / tourism industry
Beach watch

Question 25

Early EU legislation

Answer 25

Bathing waters direction (beach profiling)

Shelfish water directive

Question 26

Give some details about the Severn estuary

Answer 26

It only has two sites in which part of these sites fall into the fail category set by Bathing waters directive.