SPECIALIZED ENGLISH – SEMESTER 5DEPARTMENT OF ENVIRONMENTAL TECHNOLOGY AND MANAGEMENT Chapter 3 FUNDAMENTALS OF BIOLOGICAL Dr.. 2011 VAN LANG UNIVERSITY DENTEMA SOLID WASTE TREATMENT C
Trang 1SPECIALIZED ENGLISH – SEMESTER 5
DEPARTMENT OF ENVIRONMENTAL TECHNOLOGY AND
MANAGEMENT
Chapter 3 FUNDAMENTALS OF BIOLOGICAL
Dr Tran Thi My Dieu
Sep 2011
VAN LANG UNIVERSITY DENTEMA
SOLID WASTE TREATMENT
COMPOSTING
CONTENTS
Why composting Compost quality
Process factor Process technology
WHY COMPOSTING
Advantages
Simple system Emissions
Disadvantages Landfilling
Easy operation
Versatile
Cheap
Landscape decline Odour hindrance Difficult to plan Loss of resource
WHY COMPOSTING
Transforms waste in to compost
WASTE COMPOSTING
LANDFILL
COMPOSTING
GARDENING
?
Wastes in to compost chain is feasible only if Compost quality meet farmers demand
COMPOST QUALITY
Contaminants
Nutrients
Pathogens
Stability & organic matter
Product quality 1= free of contaminants
Non-compostables Glass
COMPOST QUALITY
Chemicals Heavy metals
Stones Plastic
Chemical waste Pesticide residues
Trang 2Management of contaminants
Waste separation
at source
h h ld
COMPOST QUALITY
Mechanical Separation
sieves
household
markets
Industry
sieves
magnetic
density
Product quality 2 = nutrients
COMPOST QUALITY
Desired Level depends on Application
Product quality 3 = free of pathogens
H man animal & plant all of concern
COMPOST QUALITY
Free = sufficient low level to prevent
contamination
Human, animal & plant all of concern
Sanitation is effect of:
Temperature
Moisture
Oxygen
Product quality 4 = stability
Stability = sufficient low level of aerobic activity under standardized conditions of
Temperature
COMPOST QUALITY
p Moisture Oxygen
Stability < or = to standard
Odour
Regrowth of pathogens
Plant disease Supression
A i f f i
WHY STABILITY
Attraction of flies
Prevention of oxygen depletion
in growing media
Structural stability in growing
media
Damage to the root is damage to the plant
COMPOSTING
COMPOSTING PROCESS
PRE-TREATMENT POST-TREATMENT
COMPOST AIR
Trang 3Composting: basic representation
OM + O 2 -> CO 2 +H 2 O + heat
Microbial Reaction
O i l P
COMPOSTING PROCESS
Optimal Process ==>
Optimal Conditions for Microbes
Process conditions
C/N ~ 25/1
T ~ 45-55 oC optimum
O ~ > 5%
COMPOSTING PROCESS
O2 ~ > 5%
H2O ~ 40-60%
Bulk Density ~ 450-600 kg/m3
Process conditions
COMPOSTING PROCESS
FUNCTION pre-treatment
Optimize material conditions for composting
COMPOSTING PROCESS
Dry matter
Windrow aeration
COMPOSTING PROCESS
Air
Seattle Tilth Composting Demonstration Site
Trang 4Aerated static pile
Air
COMPOSTING PROCESS
Air
Blower
Composting process COMPOSTING PROCESS
Composting process
Odor control critical
Environmental influence
COMPOSTING PROCESS
Lower investment
Average rate needed
Low maintenance
Low skills
Aeration Cycle: OFF 10 minutes; ON 5 minutes
20 25
55 60 65 70
Blower OFF
Oxygen
Temperature feedback control COMPOSTING PROCESS
Minutes
0 5 10 15
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
15 20 25 30 35 40 45 50
Blower ON Pile
Temperature
24
Source: Phil Leege
Trang 5Agitated-bed strategy
COMPOSTING PROCESS
Manure
In
Compost Out
Air
In
COMPOSTING PROCESS
Air photo composting plant Open heap composting
COMPOSTING PROCESS
Box/container composting Drum, with artificial aeration system
Trang 6VAN LANG UNIVERSITY DENTEMA
FUNCTION post-treatment
Particle size Removal unwanted components
COMPOSTING PROCESS
(stone, glass, plastics) Mixing with other materials (manure, peat)