국내 하수슬러지 처리현황

일일 발생량 (79개 하수처리장) : 3,495 ton-ws/day (1996년도)

처분방법

1996년 2000년 이후(예상)

매 립 76 % 15 %

해양투기 20 % 0 %

퇴 비 화 3.5 % 5 %

소 각 0.5 % 80 %

Sewage Sludge Treatment System

Wastewater

Primarysettling Aeration

Secondarysettling Effluent

Thickening Conditioning Dewatering

Composting Land utilization

DryingLand utilizationor LandfillEnergy utilization

Incineration Landfill

Energy utilization

Gas utilization MeltingCons t ruc t i onmaterial

Digestion Conditioning DewateringLand utilizationor Landfill

Multi-effectdrying Sludge fuel

Wetoxidation Dewatering Landfill

Sewage Sludge : Its Discharge Rate and Treatment Method

CountrySludge Discharge

Rate(103ton-DS/year)

Land Utilization(103ton-DS/year)

Landfill (103ton-DS/year)

Incineration(103ton-DS/year)

Ocean Dumping(103ton-DS/year)

Miscellaneous(103ton-DS/year)

Belgium 29 7.09 (27) 14.82 (51) 6.27 (22) 0 0

Denmark 150 67.50 (45) 67.50 (45) 15 (10) 0 0

France 850 233.0 (27) 446.3 (53) 170.0 (20) 0 0

German 2,180 697.6 (32) 1,286.2 (59) 196.2 (9) 0 0

Greece 15 0.4 ( 3) 15 (97) 0 0 0

Ireland 24 7.05 (29) 5.64 (24) 0 11.02 (46) 0.3 (1)

Italy 800 278 (34) 440 (55) 50 (11) 0 0

Luxemburg 15 12.1 (81) 2.76 (19) 0 0 0

Holland 202 127.2 (63) 55 (27) 6.3 (3) 11.2 (6) 2(1)

Spain 281 173.2 (62) 28.1 (10) 0 79.5 (28) 0

England 1,018 451.1 (45) 214.4 (21) 34.59 (3) 306.7 (30) 7.27(1)

USA 7,000 - (10) - (38) - (44) - (5) - (3)

Japan 1,920 384 (20) 887 (46) - 40 (2) 236 (12)

Korea 1,276 44.9 (3.5) 967.8 (76) 0.3 (0.024) 258.8 (20) 4 (0.3)

( ) : percent

Heavy Metal Content in Sludges

(㎎/㎏ of DS)

MetalKorea USA

Primary Waste-activated Digested Range Range

Fe

Pb

Cu

T-Cr

Zn

Cd

As

Hg

3419～30853

ND～304

281～546

62～204

542～1184

0.8～5.4

-

-

4805～28723

ND～193

334～831

46～266

737～1438

0.7～4.6

-

-

1243～30113

ND～164

321～638

94～209

822～1581

0.8～4.2

0.8～3.1

ND～1.7

3419～30853

ND～304

281～638

62～266

542～1581

0.8～5.4

0.8～3.1

ND～1.7

1000～154000

13～26000

84～17000

10～99000

101～4900

1～3410

1.1～230

0.6～56

Composition and Heat Content of Domestic Sludges

Sample Analysis S1 S2 S3 S4

Proximate

(wt %-DS)

Moisture 0.65 3.93 6.24 5.57

Volatiles 38.81 50.56 47.18 46.70

Fixed Carbon 6.45 7.61 7.02 3.38

Ash 54.10 37.90 39.57 44.36

Ultimate

(wt %-DS)

C 24.20 30.22 27.59 25.91

H 3.26 4.83 4.91 4.31

N 7.74 3.65 4.21 3.38

S 1.31 1.84 2.06 2.61

Heating Value (kcal/kg-DS) 2,369 3,530 3,200 3,040

Moisture Contents (wt %) 80.1 86.1 85.3 82.2

Leaching Characteristics of Sludges and Sludge Ashes

Ashsample

Ash, %a) Dewatered sludge, %a)

As Cd Cr Ni Pb As Cd Cr Ni Pb

1 17.5 0.4 0.1 0.4 0.3 15.7 3.9 1.13 13.7 0.4

2 1.7 2.4 0.4 85.6 0.2 10.0 4.7 0.05 15.1 0.6

3 14.5 1.0 0.1 0.8 0.2 4.0 1.8 0.8 3.7 0.2

4 13.5 1.1 0.01 0.3 0.2 20.0 2.1 0.2 27.3 0.04

5 1.6 13.8 0.9 79.0 0.2 5.2 33.8 0.3 78.1 0.04

6 2.3 17.5 6.4 59.1 4.5 0.5 51.0 1.9 30.0 0.7

7 15.0 5.0 0.03 51.5 0.8 9.8 6.7 0.1 15.5 1.0

8 3.9 5.0 1.3 12.1 0.1 1.5 26.5 2.8 44.9 0.1

9 1.5 2.5 0.1 80.2 0.1 5.0 6.4 0.3 54.0 0.2

10 2.8 0.6 0.01 1.6 0.1 7.5 2.1 0.1 51.6 0.3

Average 7.4 4.9 0.9 37.1 0.7 7.9 13.9 0.8 33.4 0.4

a) Computed as a percentage of total concentration.

Chemical Analysis of Sludge Ashes

Sourceof ash

Composition, % Loss onignition,%SiO2 Al2O3 Fe2O3 MgO CaO Free

CaO Na2O K2O Ba P2O5 SO3

Pusan 49.60 18.37 6.71 1.30 5.43 - 1.15 2.14 - 14.30 0.17 1.0

Pontiac 32.54 9.60 9.47 2.07 36.92 1.12 0.41 0.66 0.015 7.01 0.01 1.0

St. Paul 24.87 13.48 10.81 2.61 33.35 1.06 0.26 0.12 0.006 9.88 2.71 1.62

Kansas City 57.67 15.00 8.50 0.85 8.64 0.03 0.45 0.35 0.02 4.43 3.42 0.31

Saginaw 28.18 4.63 8.68 2.20 29.86 1.62 0.32 0.07 0.01 3.86 2.87 15.13

South Tahoe23.85 16.34 3.44 2.12 29.76 1.16 0.73 0.14 0.02 6.87 2.79 2.59

23.72 22.10 2.65 2.17 24.47 1.37 0.35 0.11 0.02 15.35 2.84 2.24

Cromwell 14.39 4.73 24.40 1.35 26.39 0.26 0.13 0.07 0.01 8.63 1.68 14.67

Cuyahoga 28.85 10.20 14.37 2.13 26.37 0.29 0.18 0.25 0.01 9.22 5.04 1.94

Expression for Determining the Softening Temperature : T(℃)＝19(% Al2O3)＋15(% SiO2＋% TiO2) ＋10(% CaO＋% MgO)＋6(% Fe2O3＋% Na2O＋% K2O)

Effect of Particle Diameter on Fluidization Velocity

Effect of Fluid Bed Particle Distribution

To Achieve Complete Combustion

Temperature : 820～870℃ (USA)

> 980℃ for thermal refractory compounds such as chlorinated compounds

850℃ (Korea)

freeboard-to-bed differential : < 250～300℉(140～170℃)

< 200℉(110℃) target

Turbulence : intimate mixing between combustion air and the fuel at low excess air (30～50%)

Time : 5 ～ 8 sec at 840 ～ 900 ℃

SSV : 2.5 ～ 3.0 ft/s ( 0.8 ～ 0.9 m/s )

Freeboard Height : 15 ～ 18 ft ( 5 ～ 6 m )

Current Research Topics on Fluidized Bed Incineration of Sewage Sludges

Basic Research

Behavior of Heavy metals during Incineration

Sulfur Capture by Addition of Limestone

Leaching Characteristics / Stabilization of Heavy metals

NO / N2O Formation and Reduction

Etc.

Field Research

Economic Evaluation of Fluidized Bed Incinerator

Utilization of Sludge Ash

Etc.

40

36

32

28

24

20

24 20 16 12 8 4 0 4 8 12

Slud

ge C

ake

, % T

S50

0 B

tu/lb

wet

600

700

800

900

1000

Btu

/lb w

et11

0012

0013

0014

0015

00 B

tu/lb

wet

1600

1700

1800

1900

2000

Btu

/lb w

et21

0022

0023

0024

0025

00 B

tu/lb

wet 30

00 3500

0 20% 35% 50% Excess Air

No. 2 Fuel Oil, gal/wet ton at 0% Excess Air Fuel, gal/wet ton at X% Excess Air

Cake Solids Concentration

- Auxiliary Fuel Requirement

Cake Solids Concentration

- Advantages of upgrading the dewatering system for a FBC operation

ParameterDewatering equipment

Existing Upgraded

TS, % 20 26

Volatiles, % 75 75

Heat content(HHV), Btu/lb of cake 1500 1950

Exhaust temperature, ℉ 1500 1500

Excess air, % 40 40

Preheated air, ℉ 1000 1000

Fuel consumption, gal/ton DS 44.0 1.9

Solids capacity, lb TS/hr 2200 3000

Power, kWh/ton DS 260 190

Scrubber water, gpm/ton DS 500 370

Operation, hr/d 18.2 13.3

The FBC is 16ft(5m) ID and operates at 20 ton/d(18Mg/d) of dry solids. Heat Content of Wet Sludge = (Calorific Value of Dry Sludge)×(%TS)×(%Volatiles)

Excess Air

Reactor Capacity, lb TS/hr/sq ft2 4 6 8 10 12 14 16 18 20

Feed

Sol

ids,

% T

S

16

20

24

28

32

36

40

W/O Preheat

Preheated Air at 1000oF

Air Preheating

Cake Solids Concentration

- Simplified determination of fuel consumption

FBR FBR MHF

Feed cake

Solids, % 22 22 22 Volatiles, % 70 70 70 Heat content, Btu/lb VS 10300 10300 10300 Cake HHV, Btu/lb wet 1586 1586 1586

Furnace operation

Exhaust temperatue, ℉ 1500 1500 1500 Excess air, % 40 40 40 Radiation, etc., % 5 5 5 Preheat temperature, ℉ 60 1000 60

Fuel requirements 2.12 2.13 2.14

Stoichiometric, gal/wet ton 13.0 4.5 - Excess air, gal/wet ton 6.6 2.2 -Total, gal/wet ton 19.6 6.7 29.0Total, gal/dry ton 44.5 15.2 132.0

Fig. 1 Flow Diagram of the Sludge Melting System with Swirling Flow Melting Furnace.

Sludge Melting System with Swirling Flow Melting Furnace

Sludge Melting System with Surface Melting Furnace

Sludge Melting System with Coke-bed Melting Furnace

Heavy Metal Recovering and Scrubbing Efficiency

mg/kg (mg/m3)

Component Sludge content

Volatiliza-tion, %

Untreated gas

Scrubber outlet

WESP outlet

Component recovered, %

Scrubber+WESP efficiency,

%

Arsenic 7.19 5 1.08(0.114)

0.164(0.0173)

0.00060(0.00038) 99.95 99.67

Cadmium 163.1 38 73.40(7.748)

21.75(2.296)

0.2530(0.0267) 99.85 99.66

Chromium 546.3 3 71.02(7.496)

0.493(0.052)

0.0167(0.00176) 99.997 99.98

Lead 220.5 18 59.54(6.284)

3.115(0.3288)

0.0402(0.00424) 99.98 99.93

Nickel 652.0 3 84.76(8.947)

0.139(0.0147)

0.0205(0.00216) 99.997 99.98

Particulates 270×103 73 27.000(2.850)

271.3(28.64)

10.61(1.12) 99.996 99.96

Vapor Pressures of Metals at Temperatures

Metal 400℉(mm Hg)

1000℉(mm Hg)

1700℉(mm Hg)

Mercury 20 10000 High

Cadmium 6.0×10-4 29 4300

Zinc 1.6×10-5 3.3 940

Lead Low 8.8×10-5 0.51