CA1054728A - Coal-base landfill, leachate treatment - Google Patents

Abstract

AN ABSTRACT OF THE DISCLOSURE

The present invention concerns the use of selected and improved adsorbent coal materials to provide a high degree of treatment for landfill leachates, in a simple, effective and economical manner. The process involves a unique way of collecting leachates from either a newer controlled type of landfill operation or the conversion of an uncontrolled type, and again the process may be used to upgrade older covered fills of refuse to correct potential leachate prob-lems therefrom. According to the invention the land-fill leachates are collected, removed and treated to an acceptable standard suitable for discharge to surface waters or re-cycling to the landfill operation.

Description

Thi8 invention relates to landfill op rations, and in particular to a method of recovering and treating thQ leachate~ therefrom before discharge.

~ early 90 per cent of the solid ~aste generated in Canada is disposed of in a landfill of on sort or another. The ban on op~n burning at these site- has led to the contamination of underground and ~urface ~aters by ~aters draining from the~e fills. Referred to a~ leachate, this contaminat~d ~ater is presu~ed to result from thc percolation of precipitation through the landfill and or by the direct interception of the ~ater table ~ith the buried refuse.

When municipalitie~ dump their garbage thcy oft-n o~erlook the hydrogeology of an area, yet~they may have kno~n for years that ~hen ~a~te i- di~posed of beneath the the ~oil, dissolvcd solids, bacteria and viruse~ can nter and tra w l in the ground~ater.

Part of the problem has been that the old--tyl-garbage dump never app ared to cau-e a hQalth problem-It ~a~ al~o kept fairly acceptable by op~n burning, and~a- usually in an out of the ~ay location. m us the publi~ had little reason to complain.

Ground~ater i~ the ba~ic ~ater source for ~any millions of CanQdian~. Leachate from solid ~aste fills is gaininq recognition aJ a ~ounting threat to ground-~at-r purity. It is eJtimated that, leachate, mainly consi-ting of rain and the contamination it 80a~8 up a~ it percolates through the refuse fill, contains about as much BOD a8 the nation's ntire di~charge of untreated ra~ sevage.

-2- 10547Z8 Soil and water are said to be polluted ~hen the health of humans or animals i8 ~mpaired b~ consuming the ~ood gro~n on the soil or by drinking the ~ater that had contact ~lth the 80il.

Wh-n ~a-te- are applied to a 80il, our exp~rtis~
in protecting ground~at-r from landfill leachate mu-t take into con-ideration the develop~ent of by-product~ or derivatives from th- leachate that may ~Q toxic or that may accumulate and threaten our food chain.

A ~a~te applied to a soil should only be consid-sred safely di-posed of ~hen a) m. EOD ha~ been lo~sred to acceptable limlt-~
in the order of 4 pp~ for liquid effluent-~

b) ~ater flo~ing over or through ths oil ~ t-th rsquired tandard~ a- to che~ical parity ta~t-, colour and odour~

c) Soil and ~ater hav- nnt been polluted and it has ~esn demonstrated that the ~aste, or its b~-products, are not building up to to~ic levels in ~oil or ~ater.

Apparently, few ba~ic studie~ related to gaining an understanding of the basic characteristics of leachates hav~ ~een reported. So~e studies done on the Pacific coast, indicate that ~leach te quantity and character i8 dependent upon the amount of moisture traveling through the ~ystem aa ~ell as the time and place~ent of the material in the landfill

-3~ 10547Z8 An analysi- of leachat- froa t~o la~df$11 sit-~hav~ been carr$ed out in coop ration ~ith the in-vantor, the results of the-e ~ea-ur ment- are sho~n in the follo~ing TableJ 1 and 2.

Table 1 Rang_ of Concentration - Sanitary Landfill Leachat-Concentration - ng/litre ~on Range Iron 200 - 1700 ~0 Zinc 1 - 13S
Pho-phat~ 5 - 130 Sulfat- 25 - 500 Chlorld~ 100 - 2400 Sodiu~ 100 - 3800 Nitrog n 20 - S00 Hardn--- (a- CaC03) 200 - S250 Che~lcal oxyg n D mand 100 - 51,000 ~ota~ R~-idu 1000 - 45,000 Nick~l 0.0~ - 0.8 Copp~r -0.10 - 9 0 pH 4.00 - 8 5 An analyois o~ the ~norganic iono pre~-nt in leachat- omanating fro~ the t~o conv-rted landfill di-po-al it~ given belo~. m e firot ~it~ $-i8 locat-d on ba~altic b drock thoreby ~llo~ing littl penetration of run off ~ater into the underground ~at-r table me r -ult- of analy~i- of a elected nu~ber of inorganic ion~ in the ~ite leachate i-a- follo~

4- 10547Z8 Compound Parts per Million pH
Ammonia 55 5 7 8 to 8 0 Copper 0.05 Chromiun 0 02 Chlorid~ 400 Caleium 132 ~luoride 0.42 Iron 1.72 Mhnganeae 0.10 10 Nitrate 14 Pho-phat- 0 65 Siliea 22 5 Sulfate 10.0 Zinc 0.05 At the seeond ~ite, th~ upper and lo~er li~it-of the coneentration of v~riou- inorganie ions ~re analy- d during the u mer ~onth~. ~h- results are glv-n b~lo~.

Co~pQ~g~ PartJ per Million pH
Iron 2.0 to 5.8 6.6 to 7.4 Fho8phat- (Ortho) 0.04 to 0 68 Caleium 160 to 240 Nagnesiu~ 80 to 150 Nitrog n (nitrate ~ Nitrite) 12 to 24 Sulfate 50 to 225 Siliea 36 to 60 Chloride 75 to 80 ~oth sulfate and iron oeeur in eoneentrations ex-e-eding the limits set by Publie Health Authorities

-5- lOS4728 Con~iderable data applieablo to the deconta~in-ation of l-aehate i8 available inee the treatm nt of eonta~$nat-d ~ater represont~ a problo~ of great eon¢ern to a ma~or portion of industrial and public ent-rpri-e~ and th- proble~ ha- been ~tudied ~xten-lvely. Conventional prlmary and aoeondary tr~atm~ntproe-a-e- ~ay not provid- the roquir d degro~ of eonri-t-ney, nor do they provide suffiei-nt tr at~ent for the proteetion of natural ~at-rs fro~ a vari-ty of organie and inorganic pollutanta, mat-rial~ ~hieh eontribute to th- ehemieal oxygen d mand, tha bio-eh-~ieal oxygen d ~and, colour, ta-te, odour~ aa ~ 11 a~ e-rtain pathogens.

R-~-areh and dev~lop~ent on advanced physioch-mieal proe -se~ for ~a-te ~ater treat~ nt ha- b -n centorod primarily on tertiary treatment proe~--e- for ~a-te alr ady ub~ et-d to convantional ~ocondary biolog-ieal tr atm-nt m. addition of t~rtiary-le~ l p ys-ioeh-~ieal process-~ to eonv~ntional eondary tr at-nent ineurs ~ignifieant additional oxpenso- ofton ~ith-out providing a eo~plet-ly atiafaetory re-ult Cl-arly, a lo~ cost, highly effoetive ~ethod ofr ~oving eontaminant~ fro~ ~ater ~ould represent a ~ignificant eontribution to the ~olution of one of ~ankind's ~oat pro-aing environmental problema A variety of approachos to ~aste ~ater treat~ent have b~ n proposed and e~p~ri~ent-d ~ith in rec-nt yoars.

-6- 1054728 Sever~l important develop~ents have giv~n a ne~
impetus to the use of activated carbon for larg-~cal- ~at~r treatment application, Activated carbon filtration constitutes a step in the t-rtiary tr at-ment proceso at the South Tahoe~ U.S., se~age treat-Dent facllity. Other inv~stigations of proces~ing ra~ ~e~ag by a t~o-step proc -- of clarification Dnd carbon ad~orption have dramatically demonstrated the potential of the techniqu- m e~e investigations have demonstrated the econoDic and practical advantage of u-ing carbon in the ~ater tr atment pr~ce~-. m-co-t of activated carbon i-, ho~ever, a large factor in the economic viability of adsorption technigue-~regeneration of the carbon when pent, is an import-ant factor in most presently co~ercial sch-m--.

A~ pr -ent, activat-d carbon i- one of th- no-t pro~i-ing olid adsorb nts o~ing to its comnercial availability, high adsorptive cap city and affinity for a broad p~ctru of ch-Dical compound-. Organic compounds that can be re~oved from aqu-ou~ solution by active carbon include phenol~, cre-ol~, alkylbenz-n-sulfonates, nitrochlorob nzenes, chlorinat-d paraffins, butadiene as ~ell a~ certain ~ynthetic d~e~, insectic-ides, and fungicides.

A~ an additional benefit, further r moval of cont-aminants has been observed as a re~ult of biological activity in carbon filter beds. It i~ thought that the highly adsorb~nt carbon surface actually enhance- the gro~th of biological organisD- because of its large surface area and it~ capacity to hold nutrient~.

lOS47Z8 With$n recent years, a large naturally occurring depDsit of carbon posse~sing propertie- ~imilar to act-ivated carbon has been located A- a re-ult of thou~ands of ch ~ical tests and practical application in th fi-ld the r ~ult- e-~ to indicate that the n tural active carbon may be as effective as the ~ynthetic-ally produeed aetivated carbon in ~a~te ~ater p~rif-ication of both organic and inorganie eonta~inant~.
If 80~ becau~e the carbon ~ay be produced at a fraction of the eo~t of high grade aetivat-d carbon, th- dr m-atic cost r duction ~ill allo~ many ne~ uses in ~at-r~
purification n eds, pr viously found economically unfea~ible.

Unlike synthetic acti~ated carbons the t--t results clearly de~on~trate a ~ignificant ad~orption capacity of th natural ~Q~ 0 activ~ carb~n for ~o-t cations and -varal anions The tests alJO suggeJt adsorption capaciti-~ comparable ~ith the best aetivated earbon-in the ea-- of phenols.

me follo~ing table ho~s the valu- of the natural carbonJ ln the treatment of conta~inant-.

Inorganic Ion Adsorption One of the unusual properties of the natural active earbon i8 its apparent ability to adsorb a variety of inorganic ions me proeedure ~ollo~ed in testing the ad~orption properties of the carbon in~ol~es (1) preparation of standard solution~ (2) s~ving of the earbon to a 1/4~ to 1/16" particle oize~ (3) three dlfferent ~ashing procedures invol~ing (a) a di~tilled ~ater ~ash, (b) a HCl acid ~ash, (c) a N~OH base ~ash, (d) a base then acid ~ash.

(PPM)Neutral Acid Ea~e Ea3e then Contact Initial Wash ~a~h Wash acid tl~e Hr~.
concentr tion zinc 30 0.6 1.0 Zinc 30 0.3 3.0 Eariu~300 22 1.0 Eariun300 5 2.0 Copper 10 0.08 4.5 6.5 1.1 Iron 10 .51 3.7 1.1 1.7 1.5 Mangane~o 1146.30 81.0 6.3 43.0 1.0 Chromate105.00 .2 .1 .1 1.0 Chromate10.025 18.0 Sulfat-2002SO.00 120.0 150.0 1.0 Ph08ph~t~ 50 37.50 33.8 1301 . 1.0 Fh08ph~t~ 50 6.0 11.1 3.0 Chloride 30 32.50 Nitrate200249.00 115.0 90.0 5.0 Nitrite109105.00 1.5 Cyanide7010.00 1.0 Cyanide70 8.00 2.0 Cyanide70 1.10 20.0 A~monium 30 5.0 1.0 A~monium 30 2.8 4.0 _9 1054728 m e results shown heretofore, clearly indicate a strong adsorption tendency to~ard mo~t cations and the anion-, CN-, Cro~ and to some extent P04 Both nitrate and phosphate have been ~igi~cantly removed by thc car~on ~hen a biological community $- devel-oped. The acid and base treated carbons appear to hav~ onhanced ability to adsorb nitrates, phos p ates, and sulfates. It should be pointed out that longer contact times ~ill pro~ably l~ad to increased adsorpt-ion since equilibrium appear to require -veral hour~ (-.g., 8ee chromate results) in oome cases.

95~3!~ k~ ption m e follo~ing ~tud$es hav~ been carried out using ph~nol and nitrobenzene Ten grans of neutral ~ashed carbon ~a- treated ~ith ten grams of pure nitrob nzene and t-n gramJ of 90X aqueou- solution of ph~nol for one hour. By ~eighing the carbon before and after xpo~ur~ to the organic the follo~ing result~ ~ere obtained~ i g of organic adsorbeq/g of carbon Phenol 0.19 Nitroben~ene 0.16 The~e results compare favorably ~ith the reJult-of a study in ~hich phenol and nitrobenzene ~ere ~d-~orbed on a larg~ ar a commercial activated carbon.
mi8 activat-d carbon, ~hich posses~ed a surface ar a of 1200 m /g, adsorb~d 0.094 grams of phonol/gram of carbon and 0.22 grams of n$trobenz~ne/gram of carbon.
m e~e re~ults sho~ that the natural carbon adsorption of the8e t~o organics i8 equal to that of a high grade ~ynthetic activated carbon.

-lo- 1054728 The following tests were done to determine the treat-ment effectiveneso of the natural carbon in which a biol-ogical community ha~ 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 Phosphate (total) 85.0 ppm 2.1 ppm Biological Oxygen Demand 750 ppm 10 ppm This invention relates in Part to Canadian Patent Appl-ication NO. 228,069 Filed May 29, 1975.

I have outlin~d heretofore the disadvantages assoc-iated with the collection and treatment of solid wastes and the leachates issuing therefrom, in both controlled and uncontrolled landfill operations, and have outlined herein by laboritory tests the benefits to be gain~d from the use of ad~orbent natural carbons for such landfill leachate treatment.

It is an object o~ the invention to provide a n~w and improved process for the collection and treatment of land-fill leachates i~suing from both controlled and uncontrolled landfill operations, that ~ill effectively ramove a variety of contaminants from the leachate.

An important objective is to remove the greater percent-age of BOD and COD from the leachates.

Another object is to remove from leachates the heavy metals therein.

A prime objective of the invention is to provide an ~`, OS47z8 adsorptive curtain wall of carbon to surround old land-- fill operations, 90 placed as to intercept and treat the horizontal flow of leachate originating from the refuse therein.

An additional object of the invention i8 to provide a process for treating landfill leachates which will re-move offensive odours therefrom.

A still further object of the invention is to provide a process for removing harmful bacteria, pathogens and vuruaes from the landfill leachates to prevent them from passing into the groundwater~-Still other objects and advantages will become appar-ent hereinafter.

I have found that the aforementioned disadvantages may be overcome and the objectives achieved by providing treat-ment for the landfill leachates as i8 shown and described in the following numbered drawings and description-In accordance with the present invention, therefore, thelandfill leachates are treated within a prepared landfill site comprising a drained impervious base, which is over-laid with an impervious liner, covered by layers of ad-sorbent carbon. A plurality of intarconnected perforated flexible pipes are laid within the carbon, and serve to gather and conduct the leachate to the collecting sump-wells, which extend vertically to the surface of the land-fill. m e refuse is placed upon the carbon, and in use the leachate passes through the refuse and is conducted through the perforated pipe to the col1Qcting well `~ `

and then pump~d to a plurality of ~eparation bed~, bio-logieal treatmant bed~, and tertiary treat~ent bed-for treat~ nt Referring no~ to Dra~ing 1 of Sheet 1, indieated at 10 i- aurface ~atcr into ~hich landfill leaehates from a typieal uncontrolled landfill op~ration ~ay ba -eping. Indieated at 11 i- a v~rtieal curtain ~all d-~igned to top the hori~ontal flo~ of ground~at-r earr~ing leaehat-~ th-r in indicat-d at 13. The eurtain ~all 11 eomprising t~o vertieal ~all eetiona, an inn r ~all indieated at 8 formed by pQrviou- polyvinal chlor-ide (P~C) heavy h~eting on the landfill ~ide, and an outer ~all for~ed by i~perviou- polyvinal ehlorid-(P~C) heavy sh--ting indieated at 9 Indicated at ~
is ho~n an inner eore of granular ~eleeted ad-orbent Coal. within the inner eore -etion 7 leaehate reeov~ry 118 lndieat-d at 12 ara r ee-~-d into tha ~a~e th-r~-of. In pr etiea th- l-aehat--ground~ater indieat-d at 13 i8-U-8 fro~ th- landf~ll ar a~ indleated at 14 and Pa---- lnto the curtain wall indieat~d at 11 through th- pervioua ~all indieated at 8. Th- l-aehat- i~ pre-vent d from pa~-ing into the ~urfae- ~at-r indieat d at 10 by the imp~rviou~ outer ~all of th- eurtain ~all indicated ~t 9, and i~ eolleeted therein for r~moval by ~ean~ of pu~plng the leaehate fro~ the ~ell~ 12.
Referrlng no~ to Dra~ing 2 of Sheet 1, indicat-d at 16 i~ a ~ell croJ~-section. Indicated at 19 i8 land-fill refus- ~ithin ~hich a ~ell 12 ~ay be ~it~d outside the eurtain ~all 11 ~he refus- leaehate 22 pass-- thr-ough the rigld p~rviou~ ~a~ 21 to b come the leachat- 23 At 24 is the 8ump section of th- ~ell and indic-_13_ 1054728 ated at 20 i8 bodrock or ~ase of the landfill aroauithin the ~oll m e leaehate 23 i- ~ithdra~n fro~
th- ~ 11 16 through th- pipe indieated at 15, at th- botto~ nd of pipe 15 i~ a ~tandard ~at-r~ell cr -n indicated at 18. The ~ithdra~al pipo 15 i~
~ad of stiff black plastie PVC indicat-d at 17.

R-ferring no~ to Dra~ing 3 of Sh -t 2, indieated at 25 i~ a controlled typ~ o~ landfill operation. Indie-at-d at 26 i- a Olid ba-e of undi~turbsd sarth, into ~hich a ground~ater eollection trap i- r~ea-~-d,th trap i- indicated at 30~ The ~all- of the trap 30 ar made of p~rviou~ ~aterial 31 within the tr~p i- laid p rforat-d ground~ater eolleetion pips- ~hieh ara indieat d at 270 ~nclooed ~ithin th- trap and forming a urround for the p rforated pipe 27 ara eleet-d ad~orb nt natural eoal ~atorials indieat d at 29. On oith-r id- of th trap 30 i~ paaced optionally a layer of p r~iou~ and or naturally adsorb-nt aeti~e earbon 29 to tbo top of the trap 30. Ov~rl~in~ th 201 ~olid ba~- 26, trap 30 and l-v-l fill indieat-d at 28 ! eo~prising ith-r perviou~ ~and or natural earbon 29 i~ a thiek icp~rvious sh-et of poly~inal ehlorid ~PVC) indieat-d at 31. A 8iX inch ba~- co~er of ~ et-d 29 naturally aetive ad-orbent coal i~ laid o~r the ntire landfill ite, into ~bieh l-aebat- trap~ 32 ar r~e~ d at interval~ acros- the refus- d~sp~-al araa 25. P-rf-orated eoll-ct~on p~pss iddieat d at 33 are laid ~itbin tho l~achate- traps 32 ~itb a surround of -l~ct-d naturall~ active ad~orbent coal 29. A solid layer of clayey 80il i8 plac~d over the entire ~or~ing aroa of the landfill as indicated at 34. At ~uitable spaced intervals perpendicular well piping indicated at 35 i8 ~oined to gether w$th the leachate collection pip~s 33 and sump 22 from which the leachate and ~ludge ~ay be pumped. Indicated at 36 i8 the refuse of the landfill operat~on.

Referring now to Drawing ~ of Sheet 2, indicated at 37 18 an uncontrolled landfill operation, the greater major-ity of this type of refuse disposal have limited if any controls governing their operations. If site plans are available for this type of landfill it is best to sink leachate recovery wells at low points indicated on the plan- Since water doe~ not always flow downhill becau~e of certain geological and impen~eable strata, it will likely be found that almost any well drilled into an old garbage dump will draw water to it, even up hill. Indicated at 38 are w 118 for the removal of leachates for treatment.

Referring now to Drawing 5 of Sheek 3, indlcat d at 40 i8 a landfill area. Indicated at 41 is the l~achate coll-ction and recovery well. The leachate i8 pumped from thewell by pump indicated at 42 and iB pa ~ed into the line indicated at 43 through ~hich i8 received the leachate to be treated. If th- leachate iB carrying large amounts of easily settled solids, it is preferably pa~ed through a settling tank, indicat d at 44, to Permit such solids to settle out. Optionally the leachate ~fflu~nt is treated with a polyelectrolyte prior to the passage of the leachate into a biological treatment bed comprising a smaller sand section indicated at 45 -15- 1054~Z8 and a larger filter section indicated at 46. The flrst treatment bed i9 shown as a dual media bed as i8 indic-ated at 47, having a first smaller section of relatively fine filter material and a larger filter section o~ rel-atively coarse filter medla. m e difference in the part-icle sizings of the media may vary according to the nature of the leachates and the type and amount of pollutants therein. Preferably the particles in the longer sQction 46 are of materials of lower density than that of the smaller section 45 Particle6. The di~ference in the density helps to maintain separation between the sections particularly during bacXwashing operations. While the desirable size range of the filter media may vary as afOrementiOnQd~ the particles o~ the coarse section 46 should be substant-ially larger in diameter than those Particles of the finer media in section 45. The coarse particles may range, for ~xa~ple, from about 1/8 inch to about 3/4 inch- m e coarse sectlon 46 should pre~erably have a depth of not more than about 12 inches and tho level of the ef~luent in the treatment bed should not be above about 8 inches as me~Jured from the bottom of the bed to provide odour control therein.

The section 45 i8 Preferably ~onmed of a relatively dense material such as silic~ sand. m e particle size should be substantially small~r than the Particle size of the coarse media in section 46. The and may range in size from about 0.04 to 0.01 inch. m e rection 4S
~hould have a depth of at least 6 inche and preferably a depth of between about 6 to 12 inches.

. .
~ "~^

-16- lOS4728 After a period of about a month or when a backpressure develops which tends to restrict the free flow of the eff-luent through the treatment beds, a cleaning procedure in-volvlng the backwashing of the beds to remove normal degrad-ation materials and windblown debris therefrom is carried out.
m is is done by passing a reverse flow of water through the beds indicated at 47. Clean water from any available source is pumped into and through the treatment beds in a reverse flow pattern to dislodge and remove the effluent degradation material8 and windblown debris from the adsorbent coal treat-ment media in the beds 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 settling tank indicated at 44 for settling. The effluent from settling tank indicated at 44 is then passed into the biological treatment bed 47 in the direction through the smaller sand filter sect-ion indicated at 45, to remove any solids there~rom and then through the longer filter section containing selected adsorbent natural coal carbon in coarse particle sizing~ therein. A
biological community is developed naturally within the bed and is enhanced by returning part of the bacteria laden out-flow from the bed to the inflow of the longer bed section 46 for the purPose of inoculation. The removal of BOD and COD
producing ingredients is carried out in the first beds indic-ated at 47 without the production of any odours therefrom by maintaining the effluent level within the beds below that of the top of the carbon indicated at 49 therein. As is indicated in a following table the bacterial content of total coliform and ~0 faecal coliform are removed by the selected natural carbon ~.

in contact therewit~ Provision is made for the removal of phosphate containing ubJtance- in the effluents by providing in the plurality of treatment beds a bed or a ~ection of a bed ~hich ~ill contain a selected natural ad~orbent carbon h~ing an affinity for po~-phatea in the effluent to renove it therefrom. me ef~lu-nt flo~ is indicated at 53 and the bacX~a~h flo~
i~ indicated at 54 me effluent from bad indicated at 47 is pa~-ed through second biological treat~ent bed 47 or a plurality of such bsds, and i~ then pa~-ed into a plurality of treatment bad~ by means of carrier line indicated at 55, ~herein tertiary treat~ent is prov-ided the leachate effluents to remove any remaining pollutant- therefrom me tertiary treatment beds indicated at 48 contain a selected natural adsorbent carbon having an affinity for tertiary type pollutant~
~hich may r main in the l-achate ~ffluents to r move thom ther~from The traated leachate e~fluent~ are then di-charged from the treatment bed of the treat~ent y-tem by means of di~charge pipe indicated at 56 for discharge to urface ~aters indicated at S2 or to be re-cyclad to the landfill operation indicated at 51.
me aforementioned ~ater discharged from the final troatment bed ~ill be of a standard of quality suitable and acceptable to pollution control agencie~ for uch discharg-s me back~as~ing of the syste~ is carried out by means of the pu~p indicated at 50 and tha ~ater carriage lines indicated at 55 -lB- 10547Z8 An idea of the treatment effect~veness of a Jelected naturally adsorbent carbon in the removal of harmful bacteria from ~a-tenater after such tr~atment ~ay be seen from the follo~ing report.

~ xc-rpt- from a letter ~on file) concerning test~
Dade by the B.C. Pollution Control Branch, a~ r ported to the Chief Health In pector, Capital Ragional Dist-rict, Victorla, B.C Dated January 22, 19~5.

~Attached are the re~ult- of test~ on th~ coal -y-tem of ~age treatment~ e ran the t-~t~ for our o~n information a~ to ho~ the material ~orked on doJe-tic e~age, ho~ever, ~e thought you might bQ intere-t-d in the r sults.~

~Ret Tr atment of Dome-tic Se~ag ~ith Pulveri~ed Coal.
A high degree o~ reduction has b~en achiev d for om p~ra~tor- includlng total and faecal colifor~ level8-h- m d-gr e of tr at~ nt prbvided by thi- ~yst-~ll better than l-vel ~A~ of the ~Mini~u~ R-quir ~ent~
for di-po~al of Municipal and do~ -tic ~astenater to Jur~ace ~ater-~.

~...JUly 3, 1974.
T. Coliform Infl. 9.2x106Eff. 9.2x104 Red. 99X
F. Colifor~ ~ 4.9x105~ 7 x103 ~ 99X

-In 8U_ ry the proce~ of the inv-ntion involve-th~ step4 of 1. Providing a suitable ~ay of collecting and rcm-oving leachates ~rom both controlled and uncont-rolled land~ill operations.

-19- ~0547Z8 2. Collecting leachate oriqinating within a controlled landf$11 operation by conducting the leachate by means of perforated piping laid within adsorbent coarsely sized coal, to recessed filter traps containing there-in the coarsely sized adsorbent coal.

3. Providing a means of settling out solid6 from the leachates by forming well sections extending to the surface of the refuse from the reces~ed 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 wells.

5. Removing the collected leachate from the wells in both controlled and uncontrolled landfill operations by means of pumps and conducting it to a settling tank.

6. Removing any r~aining effluent solids in the leachate by the addition to the leachate of an adsorbent powd-ered coal flocculating agent with agitation, and then optionally adding as required a polyelectrolyte sett- -ling agent.

7. When found necessary removing the settled sludge from the well sumps and from the settling tank and inter-mixing the sludge with - further addition of powdered adsorbent coal and recycling the coal sludge mixture back to the landfill operation.

8. Passing the effluent from the settling tank into a dual media filter comprising firstly a smaller sand section wherein the ~and particl~s have a sizing ranging in size 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 is then passed into a longer filter B
section containing therein coarse sizings of sel-ect~d adsorbent coal having a range of sizings ranging from about 1/8 inch to about 3/4 inch, whe-rein the leachate organic matter is oxidized by biological activity, and where the biological act-ivity may be enhanced by re-inoculating the biolog-ical community in the treatment bed by r~-cycling the outgoing effluent from the bed back to the first section of the coal filter m d ia.

10. Maintaining odour control within the treatment beds by keeping the effluent level in the bed below that of the top of the coal treatment media.

11. Selectively removing the total coliform, faecal col-iform and pathogenic bacteria from the landfill leachate by treatment with the selected adsorbent coal materials-

12. Removing BOD and COD causin~ pollutants ~rom thelandfill leachate~ by treatment with selected adsor-bent coal materials.

13. Providing tertiary treatment a8 a final polishing stage of leachate treatment to remove any remaining pollutants therein.

14. Di~charging after treatmQnt an effluent having a water quality of acceptable standard suitable for discharge to surface waters or for re-cycling back to the landfill operation.

lS- Provid~ng a plurality of biological and tertiary treatment beds using a plurality of differing select~d adsorb-nt coal mat-rials, for use in rem-oving pollutants from landfill leachat~s.

16. Determining the pollutant content and concsntration thereof by analysing the landfill leachates.

17. Selecting the most suitable adsorbent coals for u-e in the tr-atment o~ landfill leaehaees cho~en from the group of coals consisting of most ranks of coal and coal waste~ exeepting anthracite coal. In deter-mining the coal suitable for use in the l-achate treatment procedure thin seetions of coal are exam-ined by microphotograph study to deter~ine the phy~-ieal characteristie~, the content of surface chem-icals ~nd crystals thereon, and the adsorptivity of the eoal to remove the polluting leachat- contam-inants as found by afor~entioned analy is.

18. Crushing, pulv-rizing and sizing the selected co~ls to provid2 treatment sizings which may rang-from 3 in~hes down through -200 screen mesh size.

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-22- 10547~

19. Improving the adsorptive affinity of the selec~ted coal by a proce~ ~hich involves artificial weath-ring ~hich comprioes boiling the coal particlesin watQr for from about S to 30 minutes, or ub-~ecting the coal particle- to a steam bath, or wa-hing the coal particles ~ith ~olvent eolutions chosQn from hot or cold ~ater, an HCl acid waah, a NaOh base ~aoh, or a base then acid ~aeh. m n optionally drying the coal particle- at a temp~r-ature of from about 100C to 200C for a sufficient p~riod of time to effect the removal of the moist-urs and or ea~ily volatilized ~ub tances or gases therein, or from about 1 to 10 houro.

20. Providing selected adsorbent coal in size range-~uitable for u-e for the purpo-e intended of the invention ~herein a sizng of from about 3/4 iach up to about 3 inche- may be u-ed in the filter trap-, ao a cover for th- landfill ba~e, and for a coal ~urround for the perforated coll ction pip~- ~ithin the controlled land~ill operation.
And ~herein a powdered ~izing of the adsorbent coal i- used in the treatment of the leachate effluent passing into the settling tank for uee a~ a flocculating agent, this po~dered ~izing includes all those pulverized ad-orbent coal ~at-riala in ~hich the maxi~um size i8 that pa---ing a standard 200 mesh size ~creen. And ~herein the sizing o~ the ad~orbent granular coal mater-ials used in the biologi~al treat~ent bede and the - tertiary treatment beds a~ well a~ the curtain wRll i8 preferably of from about 1/8 inch to 3/4 inch or selected sizings ~ithin that range.

21. A further additional step is the conversion of an uncontrolled landfill operation to a control~ed landfill operation wherein a vertical impervious curtain wall is provided to surround or cut-o~f the horizontal flow of leachate is6uing from the landfill operation, within which a second vertical wall of pervious construction is placed, and wherein the pervious vertical wall and the impervious vert-ical walls are separated one from the other by an inner core comprising adsorbent granular coal in predetermined sizlngs. Leachate recovery w-lls are recessed into the base of the landfill and the aforesaid inner core section separating the two wall sRCtions. The wells consisting of a lower sump sect-ion for the collection of settleable solids from the leachate, and an upper section for the collection of the ~ettling lea~hate effluent. m e wells, ext-tending vertically from the recessed sump area through the land~ill refuse and adsorbent coal treatment m~dia to the landfill surface, are formed from rigid pervious non-degradable material. The leachate from the solid refuse percolates through the inner perv-ious vertical wall and thence through the inner core ~ection of adsorbent granular coal and is then passed through the pervious rigid wall of the collection well, and ~hen the solids are settl~d therefrom the settled effluent is then pumped from the well to a settling tank and i8 then treated by the aforement-ioned leachate process outlined heretofore.
22. Backwashing the biological treatment beds and the tert-iary treatment beds when a backpressure i9 found build-ing up within the beds which restricts the free flow of the leachate effluent therethrough and conducting the wash-debris back into the settling tank.

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-24- 10547~

22. Backwashing the biological treatment bsds and ths tertiary treatmsnt beds when a backprsssure is found building up within the beds which restricts the free flow of the leachate effluent thersthrough and cond-ucting the wash-debris from ths beds back into the ~ettling tank.

Having illustrated and described a pr~ferr-d embod-imsnt of the invention, it should be apparent to those skill~d in th~ art that the invsntion penmit~ of modific-ation in arrang~ment and detail. I claim aa my inv~ntionall such modifications as come within the true spirit and scope of the appsnded clains.

~3 .

Claims (4)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A landfill-leachate collection and treatment process including the steps of:
(a) providing a means of collecting and treating leachates from controlled and uncontrolled landfill operations, by (b) collecting leachate originating from within controlled landfill operations in perforated piping, laid within sorptive coarsely granular coal, said perforated piping laid horizontally and placed at predetermined spaced intervals with connections therebetween across the base of the entire landfill site, and leading therefrom to recessed filter traps containing said sorptive coarsely granular coal there-in, and across said landfill base, then (c) forming well sections extending upwards from said filter trap, said filter trap having a lower sump section and an upper effluent storage section, wherein said well sections are used in combination with said filter traps in said controlled landfill operations and as leachate collection and removal wells in said uncontrolled landfill operations, said wells also having pervious walls, then (d) collecting the leachates within the collection, pipes, filter-traps and wells and holding the said leachates therewithin for a sufficient period of time for the solids to settle out to form a sludge in said sump of said well, then (e) removing the leachate effluent from said wells by means of pumps and conducting the effluent to a settling tank, then (f) adding a sorptive powdered coal to the influent leachate to the settling tank as a flocculating agent with agitation and then optionally adding a polyelectrolyte settling agent to the coal-effluent mixture to form a further sludge, then (g) removing as required said settled sludge from said sumps of said wells and said settled sludge from said settling tank then intermixing said sludges with a further addition of said sorptive powdered coal and re-cycling the said coal-sludge mixture back to the said landfill operation, then if the settled leachate effluent is to be dis-charged to groundwater (h) conducting the settled leachate effluent to a dual media treatment bed comprising a first section of dense silica-sand filter media of fine particle sizings, and a second section comprising coarsely granular sorptive coal of a larger diameter sizing than that of the finer sand particles, wherein the said sand filter media is placed to a depth of at least 6 inches and preferably to a depth of between about 6 to 12 inches in said bed, then (i) removing any remaining suspended solids in the leachate effluent by passing the said effluent through the smaller filter section containing replaceable sand filter media therein, and then passing the said effluent into the larger filter section comprising adsorbent coarsely granular coal of said larger diameter sizing than the finer sand sizings, then developing a biological comm-unity within the said coal filter media and oxid-izing the organic matter in said leachate influent and re-inoculating the bed with bacteria as found necessary by re-cycling effluent leachate water from the discharge point of the said treatment bed and returning it to the influent point, then (j) maintaining odour control within the treatment beds by keeping the effluent level within the said treat-ment beds below that of the top of the adsorbent granular coal in the beds, and (k) removing all the total coliform, the faecal col-iform and pathogens from landfill leachates by passing said landfill leachates through selected adsorbent granular coal having a selective aff-inity for said total coliform, faecal coliform and pathogenic bacteria in said landfill leach-ates to remove them therefrom, and (1) removing BOD and COD causing pollutants from the said landfill leachates in contact with selected adsorbent granular coal having a selective affin-ity for such pollutants in said leachates to remove them therefrom, and (m) conducting the effluent from the said biological treatment beds to the tertiary treatment beds comprising selected adsorbent granular coal having an affinity for tertiary type pollutants including heavy metals, pesticides, herbicides, fungicides, miticides and rodenticides as well as colour prod-ucing substances, tastes, odours, acids, oils and greases, fertilizer substances detergents, chlor-inated hydrocarbons, phenols and nitrobenzene, and sewage to remove the therefrom, (n) discharging from said treatment beds an odour-free water which meets acceptable water quality standards for such discharged treated effluents for discharge to surface waters, or for re-cycling to the said landfill operation, and (o) providing a plurality of both biological and tert-iary treatment beds using a plurality of differing type of adsorbent coal treatment media, and anal-ysing the landfill leachate, prior to treatment with said adsorbent coal materials, to determine the variety of the pollutants carried thereby and the range of concentration therein, then (p) providing suitable adsorbent coals chosen from the group consisting of Bituminous Coal, Subbit-uminous Coal, Brown Coal and Lignite Coal having an adsorptive affinity for known pollutants in in the landfill leachates as determined by actual coal-pollutant test, to remove said pollutants therefrom, then (q) improving the said adsorptive affinity of said selected adsorbent coals for said pollutants in said landfill leachates by subjecting the coals to a Process involving an artificial weathering procedure, after the crushing, pulverizing and sizing of the said adsorbent coal materials, and (r) placing the said adsorbent coal on, in, and within or adding thereto the said adsorbent coal to each of the aforementioned applicational points of the said controlled and uncontrolled landfill oper-ations, in either granular or powdered sizings as may be desirable, and then (s) backwashing the said filter beds when a back-pressure is found to build up which restricts the free flow of effluent through the said beds, this is done by reversing the flow pattern and passing fresh water back through the said beds to dislodge the filter and wash debris from said adsorbent coal media in said beds and discharging it into the aforementioned settling tank.

2. The method of Claim 1, wherein the landfill leachates are held in contact with the sorptive coals within the leachate collection and treatment areas and devices to settle out solids therefrom prior to being conducted to a settling tank for treatment with a flocculating agent.

3. The method of Claim 1 wherein sorptive powdered coal flocculating agents are also mixed with incoming land-fill leachates in the settling tank prior to said treat-ment with a poly-electrolyte.

4. The method of Claim 1 wherein sorptive Powdered coal is added to said settled leachate solids pumped from said landfill collection wells and said settled solids from said settling tank in amounts of from between about .02 to 2 lbs per gallon of said sludge solids prior to said disposal in said landfill.