Treatment and Energy Recovery of Waste in China

Treatment and energy
recovery of waste in China
——A paradox for municipal solid
waste incineration in China
Prof. Dr. Zhao Youcai
Tongji University
zhaoyoucai@tongji.edu.cn

Contents
l Municipal solid wastes incineration
l Food wastes anaerobic digestions for methane and
hydrogen production
l Sewage sludge anaerobic digestions for methane
production
l Biomass to energy by pyrolysis

Municipal solid wastes in China 2010
l Refuse quantity is huge in China, 170-200 M t/a
collected in 661cities, and over 50 M t/a for rural areas
without collection
l Incineration is an option in terms of resource
regeneration and energy recovery, with over 190
plants in operation in China, over 30 M t/a being
incinerated, 30％of total MSW

Municipal solid wastes in China 2013
l Over 700 sanitary landfills, 100 M t/a being
landfilled, as a cost-effective method and storage
venue of resource
l 7 composting plants, 1 M t/a being treated, with
limited way to go for the products due to its multi-components
l 76 “integrated treatment plants”, with mechanical
separation and landfill together

Incineration styles
Both fluidized bed and stoke grate
predominate, with a percentage of
40% and 51%, respectively and
the priority of stoke grate
incinerator

Stock grate incinerator suppliers
l Overseas suppliers:
– Noell-KRC Corporation (Germany), Steinmuller
Corporation (Germany), Basic Corporation (USA),
Alstom Corporation (France), Seghers Corporation
(Belgium), VonRoll (Swizerland), Missubishi Heavy
Industries (Japan), Takuma Co. Ltd (Japan), Hitach
Zosen Corporation (Japan)
l Domestic suppliers:
– Weiming Group (WenZhou), New Century Energy
(HangZhou), San Feng (ChongQing)

Location of the incinerators
l Most of incineration
plants located in the
East and South East
China
l Zhejiang Province and
Guandong Province are
the predominated area
The distribution of incineration plants
in mainland, China 2008

Motivation driven for incineration
l Variation of waste composition
l The promotion activity of incineration plants
– a power-for-money deal situation
– a leading technology -“the face-saving project” or
“achievement Project
l The policy of tax preference, electricity price
policies and compensation for refuse treatment:
0.5-0.7 Yuan RMB/kwh, higher than that of 0.25
Yuan RMB/kwh from coal power plant

Motivation driven for incineration
l Dominated companies” pushing” and
“low cost” concepts, with over-negative
towards to landfill
l Technological superiority
— Volumn reduction: reduction rate 80%~90%
— End-of-pipe disposal：850℃~900℃,
disinfection in high temperature
— Waste-to-energy：generating capacity
300~350kwh per ton refuse ,amount to
120~140kg standard coal

Paradox of incineration plant
Cost and health worry
l Very expensive, complicated to operate,
wasteful of resources and the release of some
by-products
l One survey cited by China Daily:
– 92% of residents thought the incinerator would
harm their health, and 97% were opposed to its
construction

DCihoxainllse nge - Dioxin
l a high-level pollutant, and are listed by the
International Agency for Research on Cancer as a level
one carcinogen
l China new standard and EU DIRECTIVE 2000/76/EC
about 0.1 ng-TEQ/Nm3
l Survey on 19 incineration plants
– PCDD/Fs from 16 MSW incinerators were below the MEP
regulation level of 1.0 ng -TEQ Nm3
– only 6 systems were below the limit in EU Directive 2000/76/
EC of 0.1 ng I-TEQ Nm3

DCihoxainllse nge - Dioxin
l Low treatment fee from the local government:
5 US$, 8 US$, 10 US$, per ton waste!
l Use of little active carbon for dioxin
absorption, and even use of a few lime for flue
gas treatment
l Delay of the treatment fee payment from the
authorities concerned

MCohiastluleren ogfe w -a sDteios xin
l 60% moisture in the wastes
l Compression and bio-dewater for 5-7 days storage to
convert the moisture to leachate
l 30% leachate of the wastes generated in the summer,
with 20% in average yearly
l High cost for leachate treatment, leading to reduction
of the profit
l The potential risk of explosion: CH4 accumulating in
leachate regulating pool

The potential risk of explosion: CH4 accumulating
in leachate regulating pool
Anxi Chuangguan
Incineration Plant(600t/d):
3 killed and 2 wounded.
Concentrates of CH4、
H2、 H2S reach to
explosion limit
Shanghai Jiangqiao
Incineration Plant（1500t/
d）:
3 killed and 4 wounded, A
direct economic loss of
16.393 million yuan RMB.

The potential risk of explosion: CH4 accumulating
in leachate regulating pool

TChhea alrleean ogfe in -c iDneioraxtiionn plant should
be large enough
The area of most incineration plant is
too small
Leachate pool must be far from the
workshops and office at the plant,
e.g. 500 m away

PCohllaultlaenntsg ien f-l uDei goaxsi n- R egulation limits
l only 10% in the flue gases to be limited to “standard”
l 90% pollutants discharged into the air, even EU limit
l A huge CO2 generated
l Environmental capacity load increase. In terms of
environmental management , how many incineration
plants does a city need? How to plan site selection and
layout?

l 2000 t/d MSW incineration plant pollutant discharge
400,000m3/h x 24h x 365d x concentrations of
limit
PollutantsUnits China
GB18485-2001
lim it
EU
Total
1992 limitsdischarge t/a
Dust mg/Nm 3 8 0 3 0 100-300
HC l mg/Nm 3 7 5 5 0 140-280
SO2 mg/Nm 3 26 0 30 0 300-350
NO X mg/Nm 3 40 0 －500-600
C O mg/Nm 3 15 0 10 0 200-250
Dioxins ngTEQ/Nm 3 1 .0 0 .1
CO2 300 – 350k

FClyh aaslhl enge - Dioxin
l Promise to treat by the local government when
signing the contract, but where to go?
l Scare landfills for the fly ash
l Melting for the fly ash? Too costly
l Dumping for fly ash in many incinerators!
l Mixing with the bottom ash and dumping at the
MSW landfills

Conflict: the public VS incineration partners
l Local governments un-doing
not seriously listening to local residents’ ideas and
opinions before setting up a project of incineration plants
l Concerned community/residents health worry
afraid of the potential harm of their health and living
environment and the devaluation of their properties
l Real estate developer depreciation for the land and
properties
worry about that their properties of building will stop
appreciating after the site selection.

Nanjing Jiangbei Incineration Plant
(1200 t/d)
Guangdong Panyu
Incineration Plant (2000 t/d)
Guangzhou Huadu Incineration
Plant (1500 t/d)
Shanghai Jiangqiao
Incineration Plant (1500 t/d)
Against
refuse
incinera
-tion !

Solution for the obstacles
SCohuarclel erendguceti o-n D ait ohoxmine and on site
l Extremely difficult, practiced for over 20 years
l Many scavengers and poor people as well as
real estate keepers acted as the separators on
sites
l Nothing valuables in the wastes to be landfilled
and incinerated, and MUST be landfilled or
incinerated

DCehwaatlelerinngg oef th- eD wiaosxteisn
l Separate collection of water melon and other
high moisture wastes – seemingly difficult?
l Good cover for the garbage collection and
storage bins - seemingly difficult?
l Modification for the incineration furnace to
improve the high moisture wastes burning

SCithtiangll enge - Dioxin
l 300 m away for the inhabitants dewelling from
the incinerators for the new standard (draft)
proposed, possible? Impossible!
l At least 3000 m, enough? Where to sit?
l Extremely difficult for sitting of new
incinerators, with slow step for the incineration
increase in recent 2 years

l Application of MSW sorting in the
whole MSW management process
– Source sorting-Something difficult
– waste pickers -organized
– Mechanical separation process-applied as
pretreatment process
100
95
90
85
80
75
70
65
60
7 8 9 10 11
Separation efficiency (%)
air speed (m/s)
100
98
96
94
92
90
88
86
84
82
80
2 3 4 5 6 7 8 9 10
Separation efficiency(%)
angle(°)
v/V=0.33
v/V=0.51
v/V=0.60
v/V=0.73
v/V=0.84
v/V=0.91

Off-shore MSW Incineration Program
Yangtze Delta, Zhujiang Delta and Beijing-
Tianjian-Tangshan Delta Incineration
Plants, with 40,000 ton daily，13 million
kwh daily
All the facilities on land can be
released!

Shanghai Incineration Plant Sitting Proposal
Sitting 1 Sitting 2 Sitting 3 Sitting 4

Shanghai Incineration Plant Sitting Proposal
4（fry mountain
and fill）
Incineration
Plant
210m
600m
1
2
3
uninhabited
island
Yanshan Deep
Seaport
Jinshan Wharf
10km
Haihu
village
32km
Zhejiang
Province
Daishan
County
Daishan
County35km
Da Bai Shan
Valley Island
Use for 40,00 t/d
incineration plant
Fly ash to be landfilled
Bottom ash to be used
for land making

Yangtze River Delta
Served region: Yangtze River Delta

有机废物厌氧发酵
Food wastes anaerobic digestion

有机废物厌氧发酵 anaerobic digestion
• 厌氧发酵选择性高效产氢与产甲烷hydrogen and methane
generation
• 高速、低温厌氧发酵accelerated and low temperature
digestion
• 高温强化水解、碱预处理high temperature hydrolysis and
alkaline treatment
• 生物质干法厌氧发酵dry digestion
• 沼液微生物浓缩回用bioliquid concentration and reuse

生物质热解气化技术
Pyrolysis or gasification of
biomass

l Pyrolysis is suitable for single biomass or wastes
l Incineration is suitable for the complex wastes such as
MSW
l For MSW, 330 kwh/t waste can be got, in comparison
with a little net energy of pyrolysis in form of
combustible gas and liquid and low heating value of
the solids

回转炉热解反应器Rotational
Reactor
废物
wastes!
燃烧室!
蒸馏容器!
烧嘴
burning !
g a s
燃!
烧!
气!
体!
锅炉 t o
boiler!
残渣卸出slag!
燃料气体再循环
recycling of gas!

Sewage sludge digestion
l Silt and sand present in the sludge
l Low organic contents

Refuse Incineration Technology
Development for China
Prof. Dr. Zhao Youcai
Tongji University

Objective：
Development of refuse
incineration technology
complying with low
heating value, high
moisture, high inorganic
matters in Chinese wastes

1. Dewatering of refuse
l After 10 d storage,
moisture decreases from
72％ to 53％
l After 5 d storage, the
lower heating value
increase around 30－40％
0 2 4 6 8 10 12
Dewatering through stroage
75
70
65
60
55
50
Lower heating value vs storage time
含水率（%）
时间（d)
Biological dewatering

120
100
80
60
40
20
0
03.11-12
4
8
12
4
8
12
4
8
12
4
8
12
4
8
时间(月)
垃圾减量率(％)
Weight loss at the incineration plant storage tank
30 % moisture lost
Mechanical dewatering
WeightResults of filter pressing
Before filter
pressing
After filter
pressingWaterRate of filter
pressing
Results4330 kg 3885 kg 455 kg 10.3％
Mechanical compression, with 10.3% leachate seeping out

l Over 34％ moisture can be removed from the refuse
after 5 d storage and mechanical compression in the
holding cell in the incineration plant
l The lower heating value increases from 3800 kJ/kg
for the fresh refuse to 7200 kJ/kg for the dewatered
refuse

Air distribution layout
l Conventional air distribution:
Phase I (drying) 15%, Phase II
(combustion) 75%, Phase III (final
incineration) 10%, with high
organic matters content in the
bottom ash (5%)
l New air distribution: Phase I
(drying) 25%, Phase II
(combustion) 65%, Phase III (final
incineration) 10%, with low
organic matters content in the
bottom ash (3%)
Correlation between state of refuse incineration
and air volume through the first stage grate
25%
65%
10%
2. Air staged incineration

Hot air incineration
Conventionally, room temperature air is injected into
the furnace, resulting to a poor incineration
Our design uses the air with 280℃ in the Phase I air
Also, the length of the furnace extended from 11 m to
14.43 m (250 ton/d for each furnace)

“Water/Dilute NaOH solution/lime injection
+bag house dust collection interchange process
The flue gases in Shanghai Jiangqiao Incineration Plant
Pollutants Unit China
GB18485-2001 EU 1992 Set Discharge
Dust mg/Nm3 80 30 4
HCl mg/Nm3 75 50 30
SO2 mg/Nm3 260 300 150
NOX mg/Nm3 400 －200
CO mg/Nm3 150 100 80
Dioxins ngTEQ/Nm3 1.0 0.1 0.02
Cold water is used to wash the flue ags; NaOH solution
is used if necessary, as the pollutants are slightly over
the limits

3. Incineration improvement
Quantity of fly ash
3
2.5
2
1.5
1
0.5
0
飞灰比例(%)
03.11-12
4
8
12
4
8
12
4
8
12
4
8
12
4
8
时间(月)
Time (month)
Fly ash ratios as the refuse incinerated
Fly
ash
ratio
%
Fly ash is 1.5% of the refuse to be incinerated, in comparison with 3-5% for
the original design
The organic matters may be less 3% in the bottom ash, sometimes 1%

4. Leachate
Characteristics
Characteristics of refuse incineration leachate
Items Leachate
Fresh 1.2um 0.45um 10000Da 2000Da
pH 4.7 4.68 4.65 4.64 4.62
NH3-N(mg/l) 760.03 749.99 744.97 737.44 729.9
CODCr(mg/l) 56898 54791 52564 52166 50934
TOC(mg/l) 22300 21260 21200 20240 20040
TN(mg/l) 2108 2028 2022 2002 1940.2
Turbidity 1306.7 278 145 56 38
TP(mg/l) 181.6 173.8 170.9 118.5 108.8
Cl-(mg/l) 4398.6 4383.6 4268.7 4173.7 4148.7
SO4
2-(mg/l) 1920.3 1797 1668.3 1653.3 1671.4
TC(mg/l) 22420 21380 21360 20380 20200

Anaerobic digestion
Hydraulic retention time 8 d
COD load 5.8 kg COD/(m3·d)
Gas yield 2.885 L/(L·d)
The gas injected into the furnace so
that 1-2% more electricity can be
obtained
anaerobic
reactor

MBR
Leachate at Jiangqiao Incineration Plant
No. Item CODcr (mg/
L) BOD5(mg/L) NH4-N(mg/L) SS(mg/L)
1 leachate 48000-71000 25000-30000 380-1500 3000-20000
4 Centrifugation 38000 20000 1500 2000
5 MBR removal
(%) 98 99 99 90
6 MBR effluent 760 200 15 200
7 Set limit 1000 600 25 400

5. Fly ash and bottom ash
Diameters
Ø Partical size: 4-100μm ，
Average particle size: 19μm ，
62 μm : 90%
Ø Larger activity
Figure of SEM(1000 times) Figure of EDS

Chemical stabilization of fly ash
Mixing with Na2S, 1% may be OK
Number1 2 3 4 5 6
Na2S·9H2O（g）0.1795 0.5 1 2 4 6
S2+（mol）0.00075 0.00208 0.00416 0.00833 0.01665 0.02498
[Zn2++Pb2++…]（mol）1.0301×10-4
S2+/[Zn2++Pb2++…] 7.3 20 40 81 161 243
Leach liquor
concentration（m
g/kg）
Pb 72.65 27.37 12.65 7.3712 1.2579 1.0112
Cd 1.2342 1.0659 0.95372 0.89752 0.53296 0.44881
Mixing with organic S chemicals, 0.5% may be OK
Number1 2 3 4 5 6
Thiourea（g）0.0460 0.0760 0.1649 0.3928 0.7950 1.5345
Thiourea（mol）0.00060 0.00100 0.00217 0.00516 0.01044 0.02016
C＝[Zn2++Pb2++…]
（mol）1.0301×10-4
Thiourea/C 5.8 9.7 21 50 101 196
Leach liquor
concentration（m
g/kg）
Pb 35.72 12.56 9.798 5.589 0.9182 0.8782
Cd 1.1220 1.0220 0.84152 0.67321 0.39271 0.25245
Landfilled after
stabilization

Bottom ash
100
80
60
40
20
0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
累积百分含量（％）
平均粒度（mm）
炉渣a 炉渣b
About 60% of bottom ash（ash a:60.3%，ash
b:58.3%）consist of particles greater than
4mm. These particles are easy to be screened
and washed. Secondary building materials .
Bottom ash of refuse incineration plant
（a）raw ash（b）plastics and metals sorting
from raw ash
(a)
(b)

Resource utilization of bottom ash
100
90
80
70
60
50
40
30
20
10
0
14
12
10
8
6
4
2
0
除磷量去除率
0 200 400 600 800 1000 1200
去除率（％）
除磷量（mg/g）
初始浓度（mg/L）
Removal of P using bottom ash
COD removals from livestock wastewaters using bottom ash
Continue
water
distribution
time/h
wet/dry
weight
ratio
Influent in
run cycle/L
Influent
concentration
/mg/L
Effluent
concentration/
mg/L
Removal
ratio/%
4
1:11 4 712 53 92.5
1:8 4 687 66 90.4
1:5 4 692 86 87.5
6
1:11 6 734 72 90.2
1:8 6 703 95 86.5
1:5 6 721 131 81.8
8
1:11 8 702 74 89.4
1:8 8 694 119 82.9
1:5 8 741 176 76.3
Bottom ash containing soluble Ca, Mg, Fe, etc, and useful for the removals of P
and COD in the wastewaters

6. Incineration effects
Moisture effects
Simulative incinerator under
laboratory conditions
Impact of moisture to volatilization of
Pb, Zn and Cu oxidation state
As moisture increases, the volatility of oxides of Cu
decreases, while increases for its chloride and elemental
states, but decreases for the chlorides and elemental
states of Pb and Zn

0.00 0.18 0.36 0.54 0.72 0.90
90
80
70
60
50
40
30
20
10
0
Zn
Pb
Cr
Cu
挥发率 (%)
Cl/Sludge(摩尔/质量) (10-3mol/g)
Volatility of Zn
increases by 13.0% ,
Pb by 6.5%, Cr by
6.2% and Cu by 4.5%
Presence of CaCl2

0.00 0.18 0.36 0.54 0.72 0.90
100
90
80
70
60
50
40
30
20
10
0
Zn
Pb
Cr
Cu
挥发率(%)
Cl/Sludge(摩尔/质量) (10-3mol/g)
Presence of PVC
The volatility of Zn,
Pb and Cu
increase bu 11.2%,
18.4%，12.0%，
higher than the
presence of CaCl2，
NaCl and FeCl3; Cr
volatility increases
slightly

Treatment and Energy Recovery of Waste in China

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