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Flashcards in Sanitary Sewage Deck (30):
1

Sanitary Sewage

wastewater from households, institute and commercial establishment
threat to human health
E.Coli-> monitored for using fecal coliform tests

2

A. Problems ass w Direct Release of Sanitary Sewage

1) Release of Disease-Causing Agents (virus...)
2) Eutrophication: +N, P in water -> increase in V of aquatic plants

3

D. I & II sludge

-Dewatering to decrease V
-Anaerobic digester to generate heat + kill bac
-Digested sludge to go Sheppard LF
-go to CALGRO to further process
-applied to agriculture land

4

CALGRO

-Biosolid-to-land Program started 1983 btw the city and province
-Beneficiaries: provides Local farmers w fertilizers from biosolids
-I & II sludge taken from WWTP converted to biosolids, taken to Shepard Lagoons and Sheppard landfill

5

Rules and Regs for biosolids

crop restrictions
minimum N/P/ metal ratios
max application rates
agricultural Land pH requirements (6.5)
seasonal restrictions on land application

6

septic tank & tile beds

h2o well shouid be upgradient
min distance 25-35m

7

design of septic tank

2 basic layers
-septic tank
-drainage field (Absorption field)

8

septic tank

undergrd tank, used to separate liquids from solids
anaerobic digestion

9

drainage field

consists of a series of perforated pipes located below the soil surface
release the WW contains Suspended organic, mineral matter

10

soil type for DF

k soil
good percolation of the ww thru soil

11

depth to water table

in unsaturated zone
lots of O2 available for digestion of WW
5m below the base of DF

12

Depth of the Bed rx

>1.2 m below drainage field

13

topography

surface slope <150
shallow enough so WW doesn't run quickly off-site

14

anaerobic digestion of the organics

produces CO2, CH4, NH4
tank leaks can release large V of pathogens into the soil
be careful of bleaches + drainage cleaners - destroy the anaerobic system

15

evolution of the waste stream

1.anaerobic digestion of the organics
2.aerobic oxidation of the organic matter and NH4
3.anaerobic denitrification

16

aerobic oxidation of the OM and amonia

OM -> CO2(g) (oxidation)
NH4 -> NO3- + H+ -> by product + CaCO3 -> buffer the acids

17

anaerobic denitrification

rare
NO3 -> N2 (reduction)

18

contaminant Ass w Septic tank

CH4, NH4, CO2, trace meals

19

contaminant ass w DF

NO3-, Ca2+, CO2

20

aerobic spray system

3 tank system
-tank1: solids settle out
-tank2: air pumping to promote the aerobic digestion
-tank3: the water treated with chlorine
tank4:sprinkler system: discharge water onto surface

21

Sewage disposal options

Ocean dumping
Landfilling
Land application
Incineration
WWT facility

22

Municipal WWT facilities

Purpose: removal of SS & pathogens from water
Accomplished by: primary, secondary & tertiary treatments

23

Primary

Physical
Remove Large particles
Screen &gravitational settling tech
Solid from screen -> LF
Solid is primary sludge

24

Secondary

Biological
Remove suspended OM
Accomplished: trickling filter, activated sludge processes & BPNR bioreactors

25

Trickling filters

WW + aerated Rx bed + aerobic microbes = consumed OM

26

Activated Sludge Processes

Digested particles settle down @ bottom
Remove OM but dissolved contaminants N,P + Pathogens

27

BPNR bioreactor

3 steps process that utilizes anaerobic, anoxic & aerobic
Remove soluble N, P, OM

28

BPNR pros

Green solutions that used natural bacteria
Less sludge produced

29

BPNR cons

High skill level-worker
Expensive labs to monitor & analysis
Need a standby chem facility

30

Tertiary

Chemical
Removal of Dissolved minerals, heavy metals, pathogens
Accomplished: Cl2, UV disinfection, BPNR, chem removal of P