17.WM-RC Landfill Leachate

8/19/2019 17.WM-RC Landfill Leachate

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UniPD17.1

MSc “Environmental Engineering” - Waste Management Course

17. LandfillLandfill

leachateleachate

managementmanagement


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UniPD17.2

Leachate is a wastewater produced by the infiltration of water in the

landfill.

The water percolating through the waste removes organic compounds,

metals and salts.

The QUALT! of the leachate depends by the "uality and type of the

waste #$%&, ndustrial waste, bottom ashes', it depends by the

conditions of the degradation of waste in the landfill #anaerobiccondition, aerobic conditions, semi(aerobic condtions' and finally it

depends by the age of the landfill #new landfill or old landfill'.

The QUA)TT! of leachate depends by*

+ haracteristics of the site

+ limatic - meteorological conditions of the site

+ Physical characteristics of the waste

+ haracteristics of the barrier systems

What is leachate?What is leachate?


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UniPD17.3

ydrological balance of a landfill / &ater 0udget of a landfill

LcLi

L ∆Ubio

∆Uw%

1

232

P 4T / 4

Pe

∆Us

Pi

%urface

water

1roundwater

source


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UniPD17.4

% * infiltration from the surface water sources

23 * 2un off from surroundings to the landfill

2 * 2un off from the landfill to surroundings

P * Precipitation /rainfall

4T * 4vaporation - Transpiration

Pe * Precititation entered in the landfill body

Pi * Precipitation nfiltrated in the top cover


%ymbols

4 * 4vaporation #only'

1 * infiltration from the groundwater sources


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UniPD17.5

L * Total produced leachate

Li * Uncontrolled infiltrated leachate

∆Us* $oisture variation of top cover

Lc * ollected leachate

∆Ubio * &ater consumpion or production by

biological activity

∆Uw * $oisture variation of waste


%ymbols


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UniPD17.6

% * infiltration from the surface water sources

23 * 2un off from surroundings to the landfill

2 * 2un off from the landfill to surroundings

P * Precipitation / rainfall

4T * 4vaporation - Transpiration

Pe * Precititation entered in the landfill body

Pi * Precipitation nfiltrated in the top cover


%ymbols

4 * 4vaporation #only'

1 * infiltration from the groundwater sources

Uncontrollable

ontrollable

Avoidable

ontrollable/Uncontrollable

Avoidable


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17.7

L * Total leachate produced

Li * Uncontrolled leachate escape

5Us* $oisture variation of top cover

Lr *Leachate recovered

5Ubio * &ater consumpion or production due to biological activity

5Uw * $oisture variation of waste


%ymbols

Avoidable

Uncontrollable/

ontrollable

6

%hould be e"ual


8/33UniPD

17.


Lr Li

L ∆Ubio

∆Uw%

1

232

P 4T / 4

Pe

∆Us

Pi

%urface

water

source

1roundwater

source

!

!

!!


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UniPD17.!


Lr

L ∆Ubio

∆Uw

2

P 4T / 4

Pe

∆Us

Pi


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UniPD17.1"

L 7 Pi 8 % 8 1 9 ∆Us 9 ∆Uw 9 ∆Ubio

Pi 7 P 8 23 ( 2 : 4T

Lr 7 L : Li

onsidering that some terms are e"ual to

;ero the e"uation becomes the following*

Lr 7 L 7 P ( 2 : 4T 9 ∆Us 9 ∆Uw 9 ∆Ubio


4"uations


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UniPD17.11

#reci$itation % &ain'all * should be evaluated by

pluviometers as much close as possible to the site of thelandfill

Sur'ace runo'' * can be calculated using the followingformula

2 7 . P2 7 surface runoff #mm/d'

7 runoff coefficient

P 7 rainfall #mm/d'

7 a.bi

a : depends on the presence of the final cover, on the


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UniPD17.12

4mpirical values of =bi> for taly

4mpirical values for =a>

2U)?@@ ?4@@4)T 7 a.bi


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UniPD17.13

4vaporation - 4vaporation and Transpiration #4 / 4T'

4vaporation 7 no plants or grass on the top cover

4vaporation - Transpiration 7 plants and grass on the top

cover

Potential 4T #P4i'* $aimal 4T from surface covered with a

homogeneous,green crop with optimal water supply

1overning factors*

: $eteorological factors* &ind, Temperature, 2elativehumidity

: %oil and plant factors* Type/state of crop, %oil type


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UniPD17.14

Potential 4vapotranspiration

PE 16(

10T

I ) Cii

T

a

i= ⋅

P4i 7 potential evapotranspiration of the i(month #mm/month'

Ti 7 monthly average temperature #B'

1,51412

i01

i T )

5

T(I ∑= 7 annual thermal inde

a = 6,75 10-7 IT3 - 7,71 10-5 IT

2 + 1,7 10-2 IT + 0,423

i 7 depends on hours of sunlight and on latitude

Thorntwaite @ormula*


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UniPD17.15

i values depending on month #sunlight' and on latitude


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UniPD17.16

ow to manage the Potential 4vapotranspiration values

During the =wet> season where P : 2 C P4, 4T 7 P4 can be

assumed

During the =dry> season where P : 2 P4, it is more difficult

to evaluate the value of the 4T.

A suggestion can be the following*

4T 7 P4 . U / @

U * actual moisture content of the ground

@ * field capacity

4ven in this case an evaluation or an estimation of the U - @

values should be done.


17/33

UniPD 17.17

4vaporation

Turc @ormula*

L

a P

a P E

++

+=

1

4 7 evaporation in EF days #mm/EF days' GGG

P 7 average precipitation in EF days #mm/EFdays' GGG

a 7 amount of water that can evaporate in EF days withoutprecipitation 7 EF : F.FE3tF.H

t 7 time since the last precipitation #in seconds'

L 7 heliothermic factor


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UniPD 17.1

eliothermic factor

g I T L )2(

16

1+=

T 7 average temperature #B'

I g 7 F#F.EI 8 F.JK n/)' solar radiation

F 7 theoretica maimum solar radiation #cal/cmK/d' #see page KF'

) 7 theoretical maimum hours of incoming solar radiation #seepage KE'

n 7 effective hours of incoming solar radiation


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UniPD 17.1!

F theoretical maimum solar radiation #cal/cmK/d'

values depending on month and on latitude

) th ti l i h f i i l di ti


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UniPD 17.2"

) theoretical maimum hours of incoming solar radiation

depending on month and on latitude


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UniPD 17.21

nfiltration

nfiltration through a low permeability layer* Darcy law

Q 7 3%3i MmN/sO

* Permeability of the layer #m/s'% * Area of the layer #mK'

* ydraulic gradient #m/m'

Q * @low rate of water

&ater can permeate #infiltrate' though a porous medium only

after reaching saturation #@4LD APAT!, @'

@ definition* The volume of water which is the maximum that

a soil can hold in its pores after excess water has been drained

away; the state of a soil in this condition, when the only water

that remains is water retained by the soil particles through

surface tension.


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UniPD 17.22

nfiltration

igh permeable soils or waste can be manage at the same

way to model the infiltration.

t can be considered that due to hydraulic short circuits

through the medium, the percolation of water can appear after

the saturation of HF of the @.

W

W FC +

−=

453555.06.0

@ * @ield apacity # of dry matter'

& * &eight of E mN of waste at the average depth of thelandfill #g'

As example: MS with a density of !."# t$m%, with a moisture

content of %#&, has a '( of "!&


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UniPD 17.23

Assignment

1iven the data below and the information available in the previous slides,

calculate the leachate production of a landfill for untreated municipal

solid waste.

The following informations are available*

E' )o top cover during operation of the landfill

K' Temporary top cover realised by sandy material until the EHB year after

closure with a slope of H(EFN' @inal top cover realised by clayey material since EHB year after closure

with a slope of H

' EF meters of depth of the landfill

H' Population served* E.FFF.FFF people

J' The landfill is composed by NF sectors, each sector is completed in onesemester.

Any other re"uired data should be reasonable assumed

(he use o' E)cel is recommen*e* 'or calculations


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UniPD 17.24

Quality


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UniPD 17.25

Leachate omposition

average values acetogenic phase

average values methanogenic phase

4hrig, ERIR ruse, ERR 4hrig, ERIR ruse, ERR

p ( J,E S, I,F S,J

0?DH mg/l ENFFF JNFF EIF KNF

?D mg/l KKFFF RHFF NFFF KHFF

0?DH /?D ( F,HI F,FJ

%ulphate mg/l HFF KFF IF KF

a mg/l EKFF JHF JF KFF

$g mg/l SF KIH EIF EHF

@e mg/l SIF ENH EH KH$n mg/l KH EE F,S K

n mg/l H K,K F,J F,J

%r mg/l S E

A? Vg/l EJS KFF EFF ESKH

Average concentrations of biochemical influenced leachate components


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UniPD 17.26

Average concentrations of non biochemical influenced leachate components

4hrig, ERIR ruse, ERR

T) Mmg / lO EKHF RKF

)() Mmg / lO SF SF

ges. P / total ) Mmg / lO J J,I

hlorid Mmg / lO KEFF KEHF

)a Mmg / lO ENHF EEHF Mmg / lO EEFF IIF

As MVg / lO EJF KH,H

Pb MVg / lO RF EJF

d MVg / lO J NS,H

r MVg / lO NFF EHH

o MVg / lO HH

u MVg / lO IF RF)i MVg / lO KFF ERF

g MVg / lO E,H

T) 7 total Weldal nitrogen

Leachate omposition


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UniPD 17.27

Leachate management options

+ A. n situ * recirculation+ 0. ?n site* leachate treatment plant

+ . ?ff site* co(treatment at eternal

facilities #industrial or domestic'

+ ,

C


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UniPD 17.2

*everse +smosis

Leachate treatment options

Biological Treatment

Adsorption

+xidation

+one - /

'locculation$)recipitation - 0eutralisation

1iological Treatment

Adsorption

2vaporation

3esiccation

Leachate

cleaned

Leachate


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UniPD 17.2!

%election criteria for treatment

!oung $edium ?ld

?D #mg/l' C EF.FFF HFF(EF.FFF HFF?D/T? K,S K,F(K,S K,F

0?DH/?D C F, F,E(F, F,E

0iological treatment

hemical precipitation

?;one

2everse osmosis

Activated carbonon echange

good good4fair fair fair4poor poor


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UniPD 17.3"

e issues in leachate treatment

+ )X? in acid phase leachate is easy to degrade #X@As6'but )X? in methanogenic phase leachate is hard todegrade* t is difficult to obtain low effluent concentrationsby biological methods alone

+ Ammonia can be treated by three approaches*( 0iologically by nitrification* )8 → )?K( → )?N(

( 0iologically by nitrification(denitrification* )8 → )?K( → )?N(aerobic/anaerobic )?N( → )K⇑

( Air stripping* ncrease p #p C pa 7 R.N' and air inWection )8 → )N ⇑


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UniPD 17.31

Aerobic treatment* nfluent and effluent concentrations

!g"l


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UniPD 17.32

Activated %ludge Tan<

)itrification, Denitrification

0iological leachate treatment


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UniPD

Leachate treatment plant

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17.WM-RC Landfill Leachate