Briefing on Solid Treatment
CWRP Process Schematic
Liquid Treatment Process
Effluent Junction
Chamber
Fine Screens
Primary Sedimentation tanks
Bioreactor tanks
Secondary
Sedimentation tanks
DTSS Tunnel
Pumping
Station
Thickening
Centrifuge
Digester
Gas storage tank
Sludge
Dryer
Storage
Silo
Dewatering
Centrifuge
Solids Treatment Process
2
Solids Treatment Building
|
|
3
Solids Building
(Main Solids Treatment Facilities)
Dried Sludge
Tanks
Dewatering
Centrifuges
Sludge Drying
|
|
System
Thickening
Centrifuges Dewatered
Sludge Tanks
Sludge Tanks
4
– in the absence of oxygen.
• Acetogenesis:
– fermentation products → cetate, H2,and
Anaerobic Digestion Process
• Hydrolysis :
– Complex organic matter → simple soluble organic molecules,
– By water
• Fermentation or Acidogenesis:
– chemical decomposition of carbohydrates,
– by enzymes, bacteria, yeasts, or molds
|
|
CO2
– by acetogenic bacteria.
• Methanogenesis:
– acetate and H2 /CO→ CH4
– by methanogenic bacteria.
6
Anaerotic Digesters at CWRP
|
|
•
Constructed by SembCorp Engineers and Constructors
•5 digesters, each with a capacity of 16,800 m3
• Digester operational data
|
HRT
|
:
|
21 days
|
|
VMR
|
:
|
40-50%
|
Gas Yield: 0.77 m3/kg VM destroyed
•Digester mixing by sludge pumping
7
View of cone shaped bottom of digester
|
|
Cone Shape Digester in CWRP
•Semi Egg Shape
•Lower construction fee
8
CONSTRUCTION PROGRESS
03 NOV 02
|
|
9
CONSTRUCTION PROGRESS
04 Dec 02
|
|
10
CONSTRUCTION PROGRESS
26 Mar 03
|
|
11
CONSTRUCTION PROGRESS
03 May 03
|
|
12
CONSTRUCTION PROGRESS
03 June 03
|
|
13
CONSTRUCTION PROGRESS
04 Aug 03
|
|
14
Aerial View of Digesters
03 Sep 08
|
|
15
DECANTING & CENTRIFUGING – Process Basics
• Separation of solid or liquid particles of different densities by rapidly rotating the material
• Example of centrifuging: Spin-drying of washing machine
• Centrifuging is used to achieve good separation of two mutually insoluble liquids
|
|
• Intermediate chemicals in pharmaceutical and dyestuff
production are often filtered by centrifuging.
17
DECANTING & CENTRIFUGING – Process Basics
Solids transport in decanter centrifuges
From Sediment basin to the decanter centrifuge
Sediment basin filled with product
|
|
Sedimentation by gravity
Decanting
DECANTING & CENTRIFUGING – Process Basics
Speration by gravity
|
|
Speration by
centrifugal force
19
DECANTING & CENTRIFUGING – Process Basics
Solids transport in decanter centrifuges
Hydraulic retention time be varied by adjusting pond depth
|
|
DECANTING & CENTRIFUGING – Process Basics - Solids transport by scroll
|
|
21
Thickening Centrifuge
Thickening
Centrifuges
@1ST storey
|
|
Supplier Westfalia Separator, Germany
Total Nos 20units (18 duty, 2 standby) Current utilization rate 6 out of 20
Capacity 204.3 m3/hr
Sludge feed conc 0.5-0.8% Min output sludge conc 6%
Min Recovery 95%
Max dry polymer dosage 5.6kg/ ton of dry sludge
Max speed 2150rmp (optimal speed 1200-1500rpm) Dia. of bowl 1050mm
22
Dewatering Centrifuges
Dewatering
Centrifuges
@6th storey
Supplier Westfalia Separator, Germany
|
|
Total Nos 10units (6 duty, 4 standby)
Currentutilization rate 2 out of 10
Capacity 140 m3/hr
Sludge feed conc 3-4 % Min dewatered sludge solid content 25% Min recovery 95%
Max dry polymer dosage 12.5 kg/ ton of dry sludge
Max speed 1850rmp
Dia. of bowl 1050mm
23
Sludge Drying Systems at CWRP
|
|
25
Sludge Drying Systems at CWRP
|
|
•
Supplied by Andritz
• 5 drying system trains -using Direct Convective Drum Drying
System
• Exhaust from Rotary drum to be treated by RTO before emission.
• Max 3 in operation (Ph 1: 800,000 CMD),
(spare capacity to handle up to 1,200,000 CMD)
26
Sludge Drying Systems at CWRP
•• UUssee BBiioo--ggaass aass ffuueell
EEnneerrggyy rreeccoovveerryy rraattee:: 22..44kkwwhh//mm33 bbiioo--ggaass
•• CCaappaacciittyy ooff eeaacchh ddrryyeerr:: 9900..77 ttoonnnneess ddrryy ssoolliidd ppeerr ddaayy ooff
ddeewwaatteerreedd sslluuddggee..
•• DDrryy pprroodduucctt:: ggrraannuullaattee ooff 11 -- 44 mmmm ppaarrttiiccllee ssiizzee
9922%% –– 9966%% ddrryynneessss
|
|
•
Disposal Method future : Incineration
• Overall: 75% (3/4) reduction in weight
67% (2/3) reduction in volume
27
Fuel
Air
Sludge drying process flow schematic
Dewatered Sludge
G2,G3
25-28% DS water Air to RTO
for emission
control
Moisture Evaporation rate: 11,210 kg/h
|
|
Thermal energy input:
3,600 kJ per kg water evaporated
50oC
Cooling Water plus condensate
Dry product
92 -96% DS
28
Sludge drying process flow schematic
Dewatered Sludge
G2,G3
25-28% DS water Air to RTO
for emission
control
Return (inert) air hot water +
O2<8% water
vapour >
Recycled material 11,210 kg/h
|
|
60 – 65 %DS 95oC
50oC
Fuel
Air
FURNACE
480oC
DRYER DRUM
35oC
Cooling Water
plus condensate
Dry product
92 -96% DS
29
Sludge drying process flow schematic
|
|
be dried
The drying system used in the Changi water reclamation plant is a
direct convective drum drying system
Direct the source of heat is in contact with the material to be dried
(no heat exchangers).
Convective the material to be dried is in contact with a gaseous fluid that is hot and dry.
Beginni
Các bài viết khác
Video
| |
