Note: Descriptions are shown in the official language in which they were submitted.
lV79876
This invention relates to landfill operations, and
in particular to a method of recovering and treating
the leachate there~rom be~ore discharge.
Nearly 90 per cent of the solid waste generated in
Canada is disposed of in a land~ill of one sort or ànother.
The ban on open burning at the~e site~ has led to the
contamination of underground and surface waters by water~
draining from these fills. Referred to as leachate, this
contaminated water ~s presumed to result from the perc-
olat~on of precipitation through the landfill and or bythe dixect interception of the water table with the buried
refuse.
When municipalities dump their garbage they often over-
loo~ the hydrogeology of an area, yet they may have known
for years that when waste i~ disposed o beneath the soil,
dissolv~d sollds, bacteria and viruses can enter and travel
in the groundwater.
Part of the problem has been that the old-~tyle garbage
dump n~ver appeared to cause a haalth Problem. It was also
Xept fairly acceptable by open burning, and was usually
in an out of the way location. Thu~ the public had little
r~ason to complain.
Groundwater i~ the basic water source for many million3
0~ Canadians- Leachate from solid waste fills i8 gaining
recognition as a mounting threat to groundwater purity.
It i~ estimat~d that, leachate, mainly consisting of rain
and the contamination it soaks up as it percola~es through
the reus~ fill, contain~ about as much BOV as the nation's
entire discharge of untreated raw sewage.
"'
.
. .
107~876
-2-
Soil and water are said to be polluted when the
health of humans or animals i8 impaired by consumlng
the food grown on the 80il or by drinking the water
that had contact with the soil.
When wastes are applied to a ~oil, our expertise in
protecting groundwater from landfill leachate must take
into eonsideration the development of by-products or
derivatives from the leaehate that may be toxic or that
may accumulate and threaten our food chain.
A waste applied to a ~oil should only be considered
safely disposed of when-
a) The BOD has been lowered to aeceptable limits~
in the order of 4 ppm for liquid effluents~
.,
b) Water ~lowing over or through the 80il meets
the r quired standards as to ehemical purity,
taste, eolour and odour~
.
c) Soil and water have not been polluted and it
has been d~monstrated that the waste, or its
by-products, are not building up to toxic
levels in soil and water.
Apparently, few basic studies relat~d to gaining an
understanding of th- basie eharaeteristics o~ leachates
have been reported. Some studies done on the Pacifie
Coast, indieate that ~leachate quantity and eharacter
18 dependent upon the amount o moisture traveling through
the system a~ well as the time and placement of the
material in the land~ill.
~ ~ '
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- ~ . - . . . . ..
. . . . . . . . . . . . . . . .
- . ~ . . . . .
1079876
.
An analysi~ of leachate from two landfill ~ites have
be~n carried out in cooperation with th~ inventor, the
re~ults of these measurement~ are shown in th- following
Tables 1 and 2
T~ble 1
Range of Concentration - Sanltary Landfill Leachates
Concentration - mg/litro
Ion Range
Iron 200 - 1700
~inc 1 - 135
Phosphate 5 - 130
Sulf~to 25 - 500
Chloride 100 - 2400
Sodlum 100 - 3800
Nltrogen 20 - 500
Hardne s (as CaC03) 200 - 52S0
Ch _ lcal Oxyg-n Demand100 - 51,000
Total Rs idue 1000 - 45,000
Nickel 0 01 - 0 8
Copp-r 0 10 - 9.0
PH 4.00 - 8 5
An analysi~ o~ ths inorganic ions pr~ent in leachate
emanaeing from the two converted land~ill dispo~al ~ites
~: i8 given below me first slte i~ located on basaltic
: ~ :
bedroc~ thereby allowing littlo penetration of run-of~
wat-r lnto the underground water table. The results of
analy~io of a selected number of inorganic ions in the
lt-~leaehate i- as follows
~ ~ .
'
. - ,- -. ' ',' ... . ' ' :
~07~376
-4-
Compound Parts per Million pH :
~mmonia 55.5 7.8 to 8.0
Copper 0-05
Chromium O.oz
Chloride 400
Calcium 132
Fluoride 0.42
Iron 1.72
Manganese 0.10
10 Nitrate 14
Phosphate 0.65
Silica 22.5
& lfate 10.0 Zinc 0.05
At the second site, the upper and lower limit~ of the
concentration of variou~ inorganic ions were analysed
during the su~mer months. The results are given below.
Compound Parts per Million PH
Iron 2.0 to 5.8 6.6 to 7.4
Phosphate (ortho) 0-04 to 0.68
Calclum 160 to 240
Magnesium 80 to 150
Nitrogen
~Nitrate ~ Nitrite) 12 to 24
Sulfate 50 to 225
- Silica 36 to 60
Chloride 75 to 80
Both ~ulfate and iron o~cur in concentrations exce~d-
ing the limits sQt by Public Health Authoritie~
, ~ .
- 1~)798'76
--5--
Con~iderable data aPPlicable to the decontamination
of leachate i~ available ~ince the treatment of contam-
inated w~ter r~presents a problem of great concern to a
major portion of industrial and public ~nterPrise~ and
the problem has been studied extensively Conventional
prlmary and secondary treatm~nt processe6 may not provide
the requir~d degree of cons~stency, nor do they provide
sufficient treatment for the protection of natural waters
from a v~riety of organic and inorganic pollutants~ mat-
rials wh~ch contribute to the chemical OXygQn d~mand, the~io ~chemical oxygen demand, colour, tastQ~ odour~ ~8
well a~ certain pathogen-
Re earch and d~velopmQnt on advanc d physioche~icalproc-~se- for waste water treatment has beon centered
prlmarily on tertiary troatment proce~ses for wa~te al-
r-ady sub~ect-d to conv-ntional econdary b~ologic~l treat-
ment The addition of tertiary-level physiochemical proc-
e-se- to conventional secondary treatm-nt incurs signif-
icant addition~l exp~nses o~t-n without providing a comp-
letely sati~factory r~ult
Clearly, a low cost, highly offective method of r~mov-
ing contaminant~ from water would repre~ent ~ significant
contribution to th~ solution of one of mankind~'~ most
pre~-ing environ~ental probl~ms
~ .
A variety of approaches to wast- water treatment have
been propos~d and experimented with in rocent year~ ~
: '
1079876
-6-
Several important developments have given a new impetus
to the use of activated carbon for large scale water treat-
ment application. Activated carbon filtration constitutes
a step in the tertiary treatment at the South Tahoe, U.S,
sewage treatment facility. Other inve~tigations of proc-
essing raw sewage by a two step process of clarification
and carbon adsorption have dramatically demonstrated the
potential of the technique. These investigation~ have
demonstrated the economic and practical advantage of using
carbon in the water treatment process. The cost of act-
ivated carbon is, however, a large factor in the economic
viability of adsorption techniques~ regeneration of the
carbon when spent, is an important factor in most presently
commercial scheme~.
At present, activated carbon is one of the most prom-
l~ing solid adsorbent~ owing to its commercial availab-
ility, high adsorptive capacity and affinity for a broad
sprectrum of ch~mical compounds. Organic compounds that
can be removed from aqueous solution by active carbon
include phenol~, cresols, alkylbenzen-sulfonates, nitroch-
lorobenzenss, chlorinated paraffins, butadiene as well
as certain synthetic dyes, insecticides and fungicides.
As an additional benefit, further removal of contam-
inants ha~ been observed as a reault of biological act-
ivity in carbon filter beds. It is thought that the highly
adsorbent carbon surface actually enhances the growth of
biological organisms because of its large surface area
and its capacity to hold nutrients.
'., .''' .' , '
1079876 ~
_,_
Within reeent years, a large naturally oceurring dep-
osit of earbon possessing properties similar to aetivated
earbon ha~ been located. As a result of thousan~s of
chemical tests and praetieal application in the field
the result~ ~eem to indieate that the natural active car-
bon may be as effective as the synthetically produced
aetivated earbon in waste water purification of both
organie and inorganie contaminants. If 80, b-eause the
earbon may be produced at a fraetion of the eost of high
qrade aetivated carbon, the dramatic eost reduction will
allow many new uses in water purifieation needs, prev-
iously found eeonomieally unfeasible.
Unlike ~ynthetie aetivated earbons the test results
elearly demon~trate a significant adsorption eapaeity of
the natural form of aetive earbon!for most cations and
~everal anions. The test~ also sugge t adsorption capac-
itie~ eomparable with th- best aetivated earbons in the
ease of phenols.
The following table sho~s the value of the natural
earbons in the treatment of eontaminants-
Inorganie Ion Adsorption
-- . :
One of the unusual properties of the natural aetive
earbon is its aPParent ability to adsorb a variety of
inorganie ion~. The proeedure followed in testing the
ad-orption properties of the earbon involves (1) prePar-
ation o~ ~tandard solution~ (2) sievin~ of the earbon to
a V 4~ to 1/16H partiele 8ize~ (3) three different washing
proeedures involving ~a) a distill~d ~-
.
. .
..
:
~07~
, . . .
-8-
~ater wash, (b) a HCl acid wash, (c) a NaOH base wash,
(d) a base then acid wash-
(ppm)Neutral Açid ~ase Base then Contact
Initial Wash Wash Wa h AcidTime Hrs
concentration
Zinc 300~6 1-0
Zinc 300-3 3.0
Barium 30022 1-0
Barium 3005 2-0
Copper 100-08 4-5 6-5 1-1
Iron 10 51 3-7 1-1 1-7 1-5
Manganese 114 6-30 81.0 6~3 43.0 1-0
Chromate105-00 .2 1 1 1-0
Chromate10025 18-0
Sulfate 200250.00120.0 150.0 1-0
Phosphate 50 37-50 33-8 13-1 1-0
Phosphate 50 6-0 11-1 3-0
Chloride 30 32-50
Nitrate 200 249-00115.090.0 5.0
Nitrite 109 105-00 1-5
Cyanide 70 10-00 1-0
Cyanide 70 8.00 2.0
Cyanide 70 1-10 20.0
Ammonium 30 5.00 1-0
A~monium 30 2-8 4.0
1~79876
_g_
The results shown heretofore, clearly indicate a strong
adsorption tendency toward~ most cations and thR anion~>
CNr, CrO~ and to some extent PO~ Both nitrate and phos-
phate have been ~ignificantly removed by th- earbon ~hen
a biological community is developed. The acid and base
treated carbons appear to have ~nhanced ability to adsorb
nltrates, pho~phates and sulfates. It should be point~d
out that longer eontact times will probably lead to inc-
rea~ed ad-orption since oquilibriu~ aPPear~ to require
e~-ral hour~ g., ee chromate r- ults) in some case~
Organic Adsorption
m~ following tudios have been earried out using phenol
and nitrob-nzenQ. Ten gra~ of neutral washed carbon wa~
treat d wlth ten gr~m~ o~ pure nitrobenzen~ and ten gra~s
of 90X ~queou- olution of phenol for one hour By weigh-
ln~ th- earbon b-fore and after xpo~ure to the organie
the followlng r~ ult- wer- obtalned~
g of organie ad~orbed/g of carbon
.
Phenol 0.19
.
~ 20~NltrDb nz~ne 0.16
~, :
,
_ re~ult- eo~pare favorably with the result- o~
a tudy in ~hieh phenol and nitrobenzene wcre adsorb d on
a~larg- ar-a eo~er¢lal ~eeiv,ated earbon. Thi~ activated
earbon, ~hieh~po---s-ed~a~Ju~aee area of 1200 m2~g, ad-
eorbed 0.094 gram~ of p enol/gra~ of carbon and 0.22 grams
of nitrob-nz-n~/gram of carbon.
Th-~- r ult~how ehat th- natural earbon adJorpt$on
of~th~e~t~o~organic- 1- ~qu-l to that of a high grade
ntb~tic;~actlvaeed~carbon
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1079876
--10--
The following tests were done to determine the treat-
ment effectiveness of the natural carbon in which a biol-
ogical community has built up~ and which had been in use
in the treatment of meat-packing house wastes for a period
of 26 months without regeneration or replacement.
Contaminant Removals- Before Treatment After treatment.
_
Phosphate (ortho) 65.0 ppm .08 ppm
Pho~phate ~total) 85.0 ppm 2.1 ppm
Biological Oxygen Demand 750 ppm lO ppm
''"'
mi8 invention relates in part to Canadian Patent App-
lication No. 228,069 Pil~d May 29, 1975.
I have outlined heretofore the disadvantagQs associated
with the collection and treatment of solid wa4t and the
loachat~s issuing therefrom, in both controlled and uncont-
rolled landflll operations, and have outlined herein by
laboritory te~t~ the benefits to be gained from the use
of adsorbent natural carbons for ~uch landfill leachate
treatment-
,
It i~ an object of the invention to provide a ne~ and
improved proceQs for the collection and treatment of land-
fill leach~tes issulng from both controlled and uncontrolled
landfill operations, that will effectively remove a variety
o~ contaminant- from the leachate.
.
An important objective i8 to remove the greater percent- -
age o BOD and COD from the leachates.
Another object i8 to remove from leachates the heavy
metals therein.
.
A prime obje~tive of the invention i8 to provide an
~07~376
--11--
adsorptive curtain wall of carbon to surround old land-
fill operations, 80 placed as to intercept and treat the
horizontal flo~ of leachate originating from the refuse
therein.
An additional object of the invention i8 to provide a
ProCe8~ for treating landfill leachate~ which will remove
offenoive odours therefrom.
A still further ob~ect of the invention i8 to provide
a procees for remo~ing harmful bacteria~ pathogens and
0 VirUBe~ from the l~ndfill leachates to prevent th~m from
passing into the groundwaters.
Still other objects and advantages will become appar-
ent hereinafter
I have found that the a~orementioned disadvantages may
be o rco-e and the ob~ective~ achieved by Providing
treatment for the landfill leachatea as is shown and desc-
ribod in the ~ollowing numbered drawings and description.
In accordance with the present invention, therefor, the
landflll leachatea are treated with~n a prepared land~ill
site compris1ng a drained impervious base, which i8 over-
laid with an impervious liner, covered by layer~ of ad-
~orbent carbon A plurality of interconnected perforated
flcKible pipe4 are laid ~ithin the carbon, and serve to
gath-r and conduct the leachate to the collecting ~ump- ~-
, whi d ~xt-nd vertically to the surface of the land-
fill me refuse 1B placed upon the carben, and in use the
eachat-~pa~Qg~through the refuse and i~ conducted
through the perforated pipe to the collecting well
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.. - - . :. . : . :
7~76
-12-
and then pumped to a plurality of separat$on bed~, biO-
logical treatment beds, and tertiary treatment beds for
treatment.
Referring now to Drawing l of Sheet 1. indicated at
10 is surface water $nto which landfill leachates from
a typical uncontrolled land~ill operation may be seeping.
Indicated at 11 i~ a vertical curtain wall designed to
stop the horizontal flow of groundwater carrying leach-
ates therein indicated at 13. The curtain wall ll comp-
rising two vertical wall sections, an inner ~all indic-
ated at B formed by perviou~ polyvinal chloride (PVC)
heavy sheating on the landfill ~ide, and an outer wall
~onmed by impervious polyvinal chloride (PVC) heavy
sheet~ng indicatod at 9 Indicated at 7 i8 shown an inner
core of granular solscted adsorbent coal. Within the lnner
core ~ection 7 leachate recovery well~ indic~tod at 12
are rqcessed into the base thereof. In practice the laach-
ate-groundwat-r indicated at 13 i85ue8 from the land~ill
area~ indicated at 14 and passe~s into the curt~in wall
ind$cated at ll thro~gh the per~ibus^l~all indic~ted at 8
~he lcachate i8 prevented ~ro~ pa~ing into the sur~ace
~ater indicated at 10 by the imperviou~ outer wall of the
curtain wall indicat~d at 9, and i8 coll~ct~d therein for
r~moval by ~ean~ of pumping the leachate from the well8 12
Re~erring now to Drawing 2 of Sheet 1, indicated at 16
i8 ~ well crosa section Indicated at 19 i8 land~111 refu~e
wlthin which a ~ell 12 may be ~ited out~ide the curtain
wall 11 ~he re~u e leacha~e 22 pa~s~a through
the rigid p~rvious wall 21 to b~o~ the leachate 23
At 24 is the ~ump s2ction o~ the well and indic-
~079876
-13-
ated at 20 is bedrock or base of the landfill area
within the well. me leachate 23 i8 withdrawn from the
well 16 through the pipe indicated at 15, at the bottom
end of pipe 15 is a standard waterwell screen indicated
at 18. The withdrawal pipe 15 is made of stiff black ~-
plastic PVC indicated at 17.
Referring now to Drawing 3 of Sheet 2, indicated at :
25 i8 a controlled type of landfill operation- Indicated
at 26 i8 a solid base of undisturbed earth, into which
a groundwater coll~ction trap i8 recessed, the trap is
lndic~tl~d~ at 3Q. The walls of the trap 30 are ~ade of
pervious material 31. within the traP is laid perforated
groundwater collection pipes which are indicated at 27-
Enclo~ed within the trap and forming a surround for the
perforated pipe 27 are selected adsorbent natural coal
material~ indicated at 29. On either side of the trap 30
i- plac~d optionally a layer of perviou~ ~and or natur-
ad~orbent active carbon 29 to the top of the trap 30.
Overlying the ~olid base 26, trap 30 and level fill ind-
ieae d at 28 comprising either perviou~ sand or naturalcarbon 29 i~ a thick impervious sheet of polyvinal chloride
PVC) indicated at 31. A ~ix inch base cover o~ sQlected
29 naturally active adoorbent coal iJ laid over the entire
landflll ~lte, into which leachate traps 32 are rece~sed
at lntervals across the refuse disposal area 25. Perforated
coll-ction pipes indicated at 33 are laid within the
leachate ~rap 32 with a surround o~ selected naturally
w tlve adsorbent coal 29. A solid layer of clayey oil
18 placed ov-r the entire working area of
,
''"''
, . . ! , , , ' ~ ' ' ' '
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1079~6
. ~
-14-
the landfill as indicated at 34. At suitable ~paced
intervals perpendicular well piping indicated at 35 i8
joined together with the leachate collection pipe 33
and sump 22 from which the leachate and sludge may be
pumped- Indicated at 36 is the refuse of the landf$11
operation.
Referring now to Drawing 4 of Sheet 2, indicated at 37
i8 an uncontrolled landfill operation, the greater maj-
ority of this type of refuse disposal have limited if any
controls governing their operations- If site plans are
avallable for thi~ type of landfill it is best to sink
leachate recovery well~ at low points indicated on the
plan. Since water does not always flow downhill because
of certain geological and impermeable strata it will likely
be found that almost any well drilled into an old garbage
dump Wlll draw the~water to it, even up hill. Indicated
at 38 are well~ for the removal of leachates for treatment.
Referring now to Drawing 5 o~ Sheet 3, indicated a~ 40
is a landfill area, indicated at 41 is the leachate cQll-
ection and recovery well. The leachate i8 pumped from thewell by pump indicated at 42 and is Passed into the line
indicated at 43 through which i8 received the leachate
to be treated. ~ the leachate is carrying large amounts
of ea-lly ~ettled solids, it is pre~erably pa~sed through
a ettling tank, indicated at 44, to permit such solid~ to
~ettle out. Optionally the leachate effluent is treated
~with a poIyelectrolyte pr~or to the passage of the leachate
lnto a biological treatment bed comprising a smaller
: ~ :
~ sa*d sQction indlcated a~ 45
: ~ ~ .'.': '
.~
1079~76
-15-
and a larger filter s~ction indicated at 46. The first
treatment bed is shown as a dual media bed as i~ indic-
ated at 47, having a first smaller section of relatively
fine f~lter material and a larger filter section of rel-
atively coarse filter media. The difference in the part-
icle sizings of the media may vary according to the nature
of the leachate~ and the type and amount of pollutants
therein. Pre~erably the particles in the longer section 46
are of materials of lower density than that o~ the smaller
section 45 particles. The difference in the den~ity helps
to maintain ~aparation between the sections particularly
during backwashing operations. While th desirab}e size
range of the filter media may vary as aforementioned, the
particles of the coarse section 46 should be sub~tantially
larger in diameter than those particles of the finer
media in sQction 45- The coarse Particles may range, for
~xample, from about 1/8 inch to about 3/4 inch. me
coarse section 46 should preferably have a depth o~ not
more than about 12 inches and the level of the effluant
in the treatment bed should not be above about 8 inches
as measured from the bottom of the bed to provide odour
control therein.
The section 45 i8 preferably formed of a relatively
den~e material such as silica sand. The particle size
~hould be subatantially smaller than the particle size
o~ the coarse media in section 46. The sand may range
in size from about 0-04 to 0-Ol inch- The section 45
should have a depth of at least 6 inches and preferably
a depth of between abou~ 6 to 12 inches.
: -
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,
10'7~8~6
-16-
After a period of about a month or when a backpressure
develop~ which tends to restrict the free flow of the eff-
luent through the treatment beds, a cleaning procedure in-
volving the backwashing of the beds to remove normal degrad-
ation materials and windblown debris therefrom is carried out.
This is done by passing a reverse flow of water through the
beds indicated at 47. Clean water from any available source
iB pumped into and through the treatment beds in a reverse
flow Pattern to dislodge and remove the effluent degradation
materials and windblown debris from the adsorbent coal treat-
ment media in the bed~ as an effluent sludge, and then the
backwash water and effluent sludge is discharged from the
treatment beds indicated at 47 and carried through the carry-
ing line indicated at 48 and returned to the se~tling tank
indicated at 44 for gettling. me effluent from settling tank
ind~cated at 44 i8 then passed into the biological treatment bed
47 ~n the direction through the ~maller sand filter section
indicated at 45, to ramove any ~olid~ therefrom and then
through the longer ~ilter section containing ~elected adsorb-
ent natural coal c~rbon in coarse particle ~izings therein. Ablological community i~ d~eloped naturally within the bed
and i~ enhanced by returning part of bacteria laden outflow
from the bed to the inflow of the longer bed ~ection 46 for
th~ purpose o~ inoculation. The removal of BOD and COD prod-
uclng ingredients is carried out in the first bed~ indicated at
47 without the production of any odours therefrom by maintain-
ing the effluent level within the beds below that of the ~op
of the carbon indicated at 49 therein. As i~ indicated in a
following table the bacterial content of total colifonm and
30 faecal coliform are r~moved by the selected natural carbon ~-
1~7~8
-17-
in contact therewith. Provision i3 made ~or the removal
of phosphate containing substances in the effluents by
providing in the plurality of treatment beds a bed or
a section of a bed which will contain a ~elected natural
adsorbent carbon having an affinity for phoæphates in
the effluents to remove it therefrom. The effluent flow
is indicated at 53 and the backwash flow is indicated at
54. The effluent from bed indicated at 47 is passed through
a second biological treatment bed 47 or a plurality of
such bad9~ and i8 then passed into a plurality of treatment
beds by means of carrier line indicated at 55, wherein
tertiary treatment is provided the leachate effluent~ to
remove any remaining pollutants therefrom. The tertiary
treatment beds indicated at 48 contain a selected natural
adsorbent carbon having an affinity for tertiary type poll-
utants which may remain in the leachate effluents, to
remove them there~rom. The treated leachate effluents are
then discharged from the treatment bed of the treatment
sy6tem by m~ans of discharge pipe indicated at 56 for
discharge to surfaoe waters indicated at 52 or to be
re-cycled to the landfill operation indicated at at 51.
The aforementioned water discharged from the final treat-
ment bed will be of a standard of quality suitable and
acceptable to pollutlon control agencies for such disch-
arges. The backwashing of the system is carried out by
means of the pump indicated at 50 and the water carriage
lines indicated at 55.
-18-
An idea of the treatment effectiveness of a selected
naturally adsorbent carbon in the removal of harmful
bacteria from wa~tewater after such treatment may be
seen from the following reportO
Excerpt~ from a letter (on file) concerning tests made
by the B-C- Pollution Control ~ranch, as reported to the
Chief Health Inspector, Capital Regional District, Vict-
oria, B.C. Dated January 22, 1975-
"Attached are the results of tests on the coal system of
9ewage treatment"...We ran the te~ts for our own inform-
ation as to how the material worked on domestic sewage,
however, we thought you migh~ be interested in the results-"
"Re~ Treatment of Domestic Sewage with Pulverized Coal.
.. .. . .. . . ... . .
A high degree of reduction has been achieved for some
parameters including total and faecal coliform levels-
"---The degree of treatment provided by this system is
better than level "A" of the "Minimum Requirements for
disposal of Municipal and domestic wastewaters to sur-
face waters"-
"--July 3, 1974-
T- Coliform Infl- 9-2x106 Eff- 9-2x104 Red- 99X
F- Coliform " 4-9xlO " 7 xlO ~ 99%
In summary the process of the invention involves the
~tep~ oft
1. Providing a suitable way of coll~cting and remov-
ing leachates from both controlled and uncontrolled
landfill operations-
~798~6
--19--
2. Collecting leachate originating within a controlledlandfill operation by conducting the leachate by means
of perforated piping laid within adsorbent coarsely
sized coal, to recessed filter trap~ containing therein
the coarsely siz~d adsorbent coal.
3. Providing a means of settling out solid~ ~rom the
leachates by forming well sections extendin~ to the
surface of the refu~e from the recessed filter trap
where the well has a lower sludge sump and an upper
effluent section.
4. Collecting the leachate within the well which origin-
ates from the perforated piping, the filter traps and
through the pervious wall of the Well8-
5. Removing the collected leachate from the wells in bothcontrolled and uncontrolled landfill operations by
means of pumps and conducting it to a settling tank.
6. Removing any remaining effluent 601ids in the leachate
by the addition to the leachate of an adsorbent powd-
ered coal flocculating agent with agitation, and then
- op~ionally adding as r~quired a polyelectrolyte sett-
ling agent.
7. when found necessary removing the settled sludge from
the well sumps and f~rom the settling tanX~and inter-
mixing the sludge with a further addition of powdered
adsorbent coal and recyling the coal sludge mixture
back to the landfill operation.
~,;
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1~79~76
-20-
8. Passing the ef~luent from the settling tank into a
dual media filter comprising firstly a smaller sand
section wherein the sand particle~ have a sizlng
ranging in 6ize from about 0.04 to 0.01 and i8 placed
within the filter to a depth of between 6 inches and
12 inches.
9. The effluent i9 then pa~sed into a longer filter-
section conta$ning therein coarse sizings of selected
adsorbent coal having a range of sizings ranging from
about 1/8 inch to about 3/4 inch, wherein the leach-
ate organlc matter i8 oxidized by biological w tivity,
and where the biological activity may be enhanced by
re-inoculating the biological community in th~ treat-
ment bed by re-cycling the outgoing effluent ~rom the
bed back to the ~ir~t ~ection of the coal filter media.
,
10- Maintaining odour control within tha treatment bed~
by keeping tho ~f~luent level in the bed below that
o~ the top o~ the coal treatment media.
11. Sel~ctively r~moving the total coliform, faecal col-
iform and pathogenic bacteria from the landfill . .
leachate by treatment with the ~elected adsorbent
coal materials. `
12- ~oving BOD and COD causing pollutants from th~ :
landfill leachates by trea~nt with ~elect~d adsor-
bent coal material~-
.
.
~Lo7~6
13. Providing tertiary treatment a~ a final polishing
sta~e of leachate treatment to remove any remaining
pollutant~ ~herein.
14. Discharging after treatment an effluent having a
water quality Of acceptable standard suitable for
discharge to surface waters or for re-cycling back
to the landfill operation.
15. Providing a plurality of biological and tertiary
treatment beds using a plurality of differing selected
adsorbent coal material~, for use in removing poll-
utants from landill leachates.
16. Determining the pollutant content and concentration
thereof by analysing the landfill leachates.
17. Selecting the most suitable adsorbent coal3 for u8e
in the treatment of landfill leachates chosen ~rom
the group of coals consisting of most ranks of coal
and coal wastes excepting anthracite coal~ In deter-
mining the coal suitable for use in the leachate
treatment procedure thin sections of coal are exam-
ined by microphotograph ~tudy to determine the phys-
ical characteristics, the content of surface chemic-
als and crystals thereon, and the adsorptivity of
the coal to remove the polluting leachate contamin-
ants as found by aforementioned analysis.
18. Cru~hing, pulverizing and sizing the selected coals
to provide treatment sizings which may range from
3 inche~ down through -200 screen mesh Bize-
:
`` 10798~76
-22-
19. Improving the adsorptive affinity of the selected
coal by a proces~ which involves artif$cial weath-
ering which comprise~ boiling the coal particles
in water for from about 5 to 30 minutes, or sub-
jecting the coal Particles to a ~team bath, or
washing the coal particles with solvent solutions
chosenfrom hot or cold water, an HCl acid wash,
a NaOh base wash, or a base then acid wash. Then
optionally drying the coal particles at a temper-
ature of from about 100C to 200C for a sufficient
period of time to effe~t the removal of the moist-
ure and/ or easily volatilized subetances or gases
therein, or from about 1 to 10 hours.
20. Providing selected adsorbent coal in si~e ranges
~uitable for use ~or the purpo~e intended of the
invention wherein a sizing of ~rom about 3/4 inch
up to about 3 inches may be used in the filter
traps, a~ a cover for the landfill base, and for
a coal surround for the perforated collection
pipes within the controll~d land~ill operation.
And wharein a powdered sizing of the adsorbent
coal is used in the treatment of the leachate
effluent passing into the settling tank for use
as a flocculating agent~ this powdered sizing
includes all those pulverized adsorbent coal
materials in which the maximum ~ize i8 that
pa~ing a standard 200 mesh size screen- And
wherein the sizing of the ad60rbent granular coal
materials used in the biological treatment beds
and the tertiary treatment beds as well as the
curtain wall is preferably of from about 1/8 inch
to 3/4 inch or ~elected sizings within that range.
'. . . ..
-23-
21. ~ further additional step is the conversion of an
uncontrolled landfill operation to a controlled
landfill operation wherein a vertical lmpervious
curtain wall i9 provided to surround or cut-off the
horizontal flow of leachate iæsuing from the landfill
operation, within which a second vertical wall of
pervious construction i9 placed, and wherein the
pervious vertical wall and the impervious vertical
walls are separated one from the other by an inner
core comprising adsorbent granular coal in predet-
ermined sizings. Leachate recovery wells are recessed
~nto the base of the landfill and the aforesaid inner
core section ~eparating the two wall sections. The
wells consisting of a lower sump section for the
collection of settleable solid~ ~rom the leachate,
and an upper section for the coll~ction of the sett-
ling leachate e~fluent. The wells, extending vertic-
ally from the recessed sump area through the landfill
refuse and adsorbent coal treatment media to the
landfill surface, are formed from rigid perviou~
non-degradable material. The leachate from the solid
refuse percolates through the inner pervious vertical
wall and thence through the inner core ~ection of
adsorbent ~ranular coal and is then passed through
the parviou~ rigid wall of the collection well, and,
when the ~olids are settled therefrom the ~ettled eff-
luent i8 then pumped from the well to a settling tank
and i8 then treated by the aforementioned leachate
proce~8 outlined heretofora.
: ' . . :. . .: ................... . '
.
79!~6
-24-
22. Backwashing the biological treatment beds and the
tertiary treatment bed~ when a backpressure is
found building up within the beds which restricts
the free flow of the leachate effluent therethrough
and conducting the wash-debris from the beds back
into the settling tank.
Having illustrated and de~cribed a preferred embod-
iment of the invention, it should be apparent to those
skilled in the art that the invention permits of modif-
ication in arrangement and detail. I claim as my inven-
tion all such modifications as come within the true
spirit and scope of th~ appended claims.
