BRUNNER, Willi (Attikerstrasse 10, Wiesendangen, CH-8452, CH)
| CLAIMS 1 An artificial aquifer for decreasing the contents of metals metalloids nitrate nitrite pesticides and organic micro contaminants in natural groundwater, artificial fi infiltrated ground water from surface water and comprising a basin (1 ) of filling material creating a reaction zone (5), a feeding line (3) one oi more satellite wells (4), at least one main well (6) and at least one pumping well (7), characterized in that the feeding line (3) is applied in the upper outer periphery of the basin ( 1 ) and wherein the main well (6) is connected to a pumping well ( 7) via a bottom outflow ] 0 provided with a regulating valve (13) to maintain a given level of water in the aquifer 2 An artificial aquifer according to claim 1 wherein the artificial aquifer has a shape selected from a group of shapes consisting of circulai oval hexagonal octagonal I ^ and a shape dictated by the surrounding tei rain 3 An artificial aquifei accoi ding to claim 1 whei ein the satellite wells (A ) are ai t anged in a circular pattern inside the feeding line (3) ]{) A An artificial aquifer according to claim 1 whei ein the feeding line (3) is placed at a distance from the outer peπphei y of the basin that is less than 1 /40th of the diametei of the aquifer prefei ably less than 1 /bθ" of the diametei paiticulai ly less than 1 /60"' of the diametei and more pi efei ably less than 1 /100" of the diametei .2 ^ b An artificial aquifci accoi ding to claim 1 whei ein the bottom of said basin is covoi ed with an impermeable sheet to i educe loss of watei from the basin 6 An artificial aquifer according to claim 1 wherein said basin is filled with natui al washed or unwashed material which is commonly used foi the pui ification of ground M) watei 7 An artificial aquifei according to claim 1 wherein said feeding line (3) consists of a perforated tube through which the watei to be pi ocessed is fed and pei meates through into the reaction zone 8 An artificial aquifei accoiding to claim 1 wheiein said main well is a vertical main well which vertical main well comprising a oeifotated tube holding the filling material of the aquifer out but allowing water to penetrate into the well S 9 An artificial aquifei according to claim 1 wherein an airtight lid is provided at top of said main well 10 An artificial aquifer according to claim 1 whetein an impeimeable geomembrane is applied as a cover on top of said aquifei K) 11 A method foi decreasing the contents of metals metalloids nitrate nitrite fluoride pesticides and organic micio contaminants in natural giound water or artificial infiltrated giound watei from suiface watei using an artificial aquifei wheieby the watei to be processed is infiltiated into a basin (1) of filling mateiial cieating a I ^ ieaction zone (b) thiough a feeding line (3) piocessed in one oi moie satellite wells (4) and passed to at least one main well (6) and a pumping well (7) wheieby the feeding line (3) is applied in the uppei outei penpheiy of the basin (1) theieby avoiding so called dead /ones in the aquifei and providing foi a highei degree of puiification and wheieby watoi having been puiified is withdiawn fioni the aquifei "M) via the main well (6) which is connected to a pumping well (7) via a bottom outflow provided with a regulating valve to maintain a given level oi watei in the aquifei λ? A method accoiding to claim 11 wheiein the main well (6) is brought in contact with the sutiounding atmospheio theieby avoiding any negative piessuie in the aqunei 13 A method as claimed in claim 11 wheiein watei \^ Hushed out from said satellite wells into said ieaction zone in a ciiculai pattern to allow the ieaction zone to lecovei inteimittently and to cieate a balanced woiking piessuie on the miciooiganisms acting in said /one 10 }-> |
GROUND WATER PURIFICATION PLANT BASED ON BIOLOGICAL OXIDATION AND
REDUCTION PROCESSES
S DESCRIPTION
Field of the Invention
The piesent invention i elates to an artificial built aquifer foi the purification of raw water and in particular foi cteating at least one reaction zone in the artificial aquifei foi circulating and put ifying giound and ιaw water in paiticulai for drinking watei use which artificial 10 aquifei comprises seveial satellite wells and at least one extraction well
Background of the invention and Prior Art
Purification of water becomes more and moie impoitant due to contaminations obtained in ground water leseivons so called as natuidl aquifeis
1 - Ϊ
Commonly puiification of watei takes place by having watei pnmaiily icactod with diffeient oxidation agents then having it penettated thiouqh specially anangod layeis of giavel sand and othei mateuals and then tianspoiting the watei thus puufied via a pipeline system optionally piovided with piessuie ιικ leasing pumping stations and/oi watei toweis
0 O to the consumei
Giound watei and ιaw watei which aic used foi drinking oi tap watei pioduction often contain high amounts of iion manganese aisenic fluoiide and othei tiace elements High levels of above mentioned tiacc elements have to be i educed befoic the watei can be
" ^ used foi tap watc i (dunking pψpυ°e) H ue f c health and taste ι°ason c HP Λ 0 160 n Λ desciibes the use of a zone foi oxidation and pteπpitation of it on and manganese where watei containing oxygen oi oxygen pioducing compounds inteimittent aie added to the zone via satellite wells ananged aiound exti action wells lleieby water is fed only to a few satellite wells and simultaneously watei is extiacted fiom adjacently situated satellite wells
^O 1 he watei punched with oxygen and fiee of any an bubbles is foiced clown the satellite wells The addition of dissolved Oxygen cieates a suitable giowth enviionment foi microoiganisms piesent in the giound which miciooiganisms togethei with chemical and/oι biochemical piocesses piovide foi piecipitation of ii on and manganese in the zone/giound layei which will setve as a leactive filtei foi the removal of aisenic fluoride i"i and othei tiace elements lion oxidizing bacteua assists in the oxidation of feπous it on of the untieated watet This action is iepeated at specific inteivals to obtain puie watei I towevei it is not only it on and manganese that aie a ptoblem but other metals metalloids nitrate nitrite pesticides and oiganic sourced micro contaminants need to be eliminated to produce a healthy water particularly when consideiing tap watei quality
"> In earlier patent (US 475304) another method to impiove the above process was used which included woikinq with three so called mainwells which were placed with linear distances of 600 metei to 1000 meter fi om each well Groundwater was pumped up from one well and part of this water was enriched with oxygen and iecharghed into the othei two wells The circular auangement of oxygenated water aiound the recharghed wells allowed I 0 to withdraw a limited amount of purified water before again a recharge had to occur 1 his system showed seveial disadvantages in the operation energy consumption and lemoving of other trace elements than Iron hurthei on this was not an artificial aquifei but was built in the natuial aquifei
1 ~> IIP A 0154105 desei ibes i eduction of nitiate in giound water by means of denitiitication in a i eduction zone cieated between injection/satellite wells also aπanged aiound one oi more extraction wells
Accoiding to the method and system as disc losed in f P A 016410b a diffeiont method of creating oxidation and i eduction /ones was peiceved and achieved An oxygen 0 eniichment system is placed above giound in the satellite wells to covei thus oxygenating the pumped up watei befoie flowing back into the satellite wells In these wells a separator was pic sent in each well which divided the well into an uppei and a lowei pait Inflow of compiessed an is achieved through a first pipe into ihe upper half of the well and thiough a second pipe into the lowei hah of the well Water may be pumped tiom the uppei half of ^ the well fo> 3 ccitain time dui ition aftei whic h it may be pumped from the lowei half oτ the well foi the remaining time duiation In the disclosuie the feeding of watei ι ι iestiicted to some wells to cieate a deniti ification zone Theieby all the aquifei is not used foi denitrification puιpo c e O It is pieviously known to cieate ieartion zones in aquifers to obtain an oxidation and a pieripitation /one oi a ieduction zone between a number of injection oi satellite wells auanged aiound one oi nioie extraction wells in such reaction zones wheieby the zone desned is cieated inleimiUently oi continuously between each pan of adjacent situated injection wells Py introducing oxygen oxygen containing gas or oxygen releasing
11 compounds in the watei of the two injection wells when one cieates an oxidation and piecipitation zone oi introduce an oxygen consuming compound in the injection wells to obtain a i eduction /one and whereby one pumps the watei of one of the satellite wells into the neighbouring satellite well so that a circulation circuit is created in the aquifer between the two satellite wells
-> However in ceitain areas of the globe the natural layers have been destroyed by contaminants or theie is a lack of natural uniform layeis with suitable material compositions Foi that reason artificial aquifers have been proposed wheieby the artificial aquifer consists of a basin normally covered with an impermeable cloth or sheet to provide a defined volume The basin is then filled with gravel and sand and is provided with K) tubings and wells to a) add giound watei oi any other raw watei to the basin b) create the demanded reactive zone foi the precipitation and c) to remove the water having been treated in the basin
The piesent invention is based on the known in situ process with the name Vyiedox oi
1 ^ Nitiedox 1 he ai tificially built plant will be opeiated uridci the same conditions as cieated in the natuial in situ planis I he bottom of the present plant is tightened up with a impei meable membiane to isolate the plant fiom ihe natuial giound aquifei and to piovide foi the possibility to u ^ c special natuial denved Wcishcd oi unwashed filling matonals to cteate ideal conditions foi the spiead out of ihe activated reactive /one as quick as
H ) possible as well as to maintain the appiopnate flow and hydiologic al conditions
P 1416469 i elated to a ceitain constitution of satellite well pipes also discloses the use. oi artificial aquifeis whciein the supply tubing is placed midway down in the icaction zone o( gi WPI and sand
Io oveicome the pioblems aiising due to clogging of tie eailiei embodiment 0 system as discussed in patent [P 14364G9 and method was denved Piessuie inlet pipes were introduced in the uppci half as well as the lowei hah of the wells Ihe uppei half and lowei half were defined by intioduction of a balloon body which acted as a sepaiatoi Conduits
• >() suppoited the piessuie inlet pipes in each half A ciiculation vessel was provided above the giound ovei each well Initially an /watei was supplied to the uppei half of the well and watei was pumped upwardly into the circulation vessel foi being de aeiated The watei flowed then by giavity into the lowei half of the well below the balloon body This pioceduie was earned out for a certain time duiation in one oi more satellite wells In
^ anothei satellite well or foi the iemainmg time duration an was piessun/ed into the lowei half of the well below the balloon body The upflow of water was directed into the aeration and de-bubbling vessel This de-bubbled watei flows back into the top half of the well before it passes out of through the well screen into the ground
WO 2006/014126 discloses another artificial aquifer working under a negative pressuie S and therefore using a complete water and air tight enclosure Also in this case the supply tubing is placed midway down in the aquifer and the satellite wells are special designed
Fuithei enhancements in WO 2006/014126 patent application included placing a pluiality of satellite wells in a circular oi iectangular way, as well as one extraction well in then
K) centre 1 he infiltiation system was arranged close to the satellite wells An oxygen eniichment system was placed above ground These wells and infiltiation system weie placed in aitificial aquifers developed by placing filter material to define a manmade basin of the aquifei beneath the ground There was a need to hermetically seal all these wells and all covei ing Due to this specific assembly, dead zones weie created at the sides of the
I^ aitificial aquifei The dead/ones weie cieated due to non-ciiculation of water in those /ones In its typical wot king watei enteied the satellite wells thiough its peimeable sci eons befoie being diiected out to the oxygen eniichment system Oxygenated water ie enteis the satellite wells and theiefoie the whole of the aquifei 1 he main flow of watei is thus established that μunfied watei enters the exti action well in the centre and can be
"1 O pumped out foi use fhe hermetic sealing of the aquifei is needed foi the pioposed opeiation under negative piossuie The inhomogeneity between the activated /ones and the dead /ones provides seveie issues Woiking undei negative piessuie is veiy energy consuming and lequnes a veiy high technological sealing to be acquned Thus it is high energy and cost requiiing
I hus in these known constructions dead zones will be cieated in par ticulai over the supply tubing which dead /ones will distuib the activity in the reaction /one as the environmental differences between the dead zones and the ieaction /one aie too gieat
K) A further pioblem solved is to maintain the growth environment of the miciooiganisms cai lying out the purification of the watei in the aquifei Thus the aquifei may not be dried out ie emptied completely changing the hydrology around the miciooiganisms
Summary of the invention
IS The piesent invention i elates to an artificial aquifer having eliminated dead zones The ptesent invention thus relates to a method foi deci easing the contents of metals metalloids nitiate nitrite pesticides and oiganir micio contaminants in natural giound watei aitifiπal infiltrated giound water from suiface water according to the appending claims In a further aspect the present invention ielates to an apparatus for cariying out the method
According to this invention there is provided an artificial aquifer for decreasing the contents of metals metalloids nitrate nitrite pesticides and organic micio contaminants in natural gioundwater artificial infiltiated ground water from surface watei and compiising a basin of filling material creating a reaction zone a feeding line one or mote satellite wells at K) least one main well and a pumping well chaiacteuzed in that the feeding line is applied in the upper outei pet iphery of the basin and wheioin the main well is connected to a pumping well via a bottom outflow piovided with a regulating valve to maintain a given level of watei in the aquifer
1 -> 1 ypit ally the satellite wells may be arianged in a circular pattei n inside the feeding line
Typically the feeding line may be placed at a distance fi ini the outei penμheiy of the basin that is le L o than 1/4O 1 of the diamctei of the aquifei picfeiably less than I/'^O" of the diametei preferably less than 1/60" of the diametei and moie ptefei ably less than 1/100" 1 O of the diametei
Iypically the bottom of said basin may be coveied with an impermeable sheet to ieduce loss of watei horn the basin
" * Typically aid basin is filled with natuial w ) c hed oi unwa s hed mateinl which s common'y used foi the pui ideation of giound watei
Iypically said satellite wells aie ananged veitical into the mateual used foi filling said basin
fypically said feeding line may consist of a perforated tube thiough which the watei to be piocessed is fed and piessed out into the ieaction zone
Iypically said main well is a veitical main well which veitical main well being located l~i substantially in the middle of said aquifei Typically said main well is a vertical main well which veitical main well consisting of a perforated tube holding the filling material of the aquifer out but allowing water to penetrate into the well
~> Typically an outflow tubing is provided for establishing communication between said main well and said pumping well foi pumping water out of said main well
Typically a non closing lid covers the top of said main well
10 Typically an impermeable geomembranc may be applied as a covei on top of said aquifei
Typically a process contiol unit is connected for controlling the feeding in of water in said aquifer
1 Λ Typically a piocess control unit is connected foi conti oiling the feeding out of watei fiorn said main well
Λc coi ding to this invention there is piovidod a method foi decicasinq the contents of metals metalloids nitiaie nitiito fluoiidc pesticides and oiganic micio contaminants in O natuial giound watoi ot aitificidlly infiltiated giound watci fiom sulfate watei using an artificial aquifei wheieby the watei to be piocessed is infiltiated into a basin of filling material ci eating a ieaction /one though a feeding line piocessed in one oi moie satellite wells and pa c sed to at least one main well and i pumpinq well whereby the feeding line is 3ppl ec 1 ir tl e ippei outei penphery o f the hi c 1 I t h et^b > " "voiding so called dead zone*- in ^ ihc at) u if c i and pioviding foi a hiqhei clegiec of puiific ation ind wheieby water having been puiifiod is withdrawn fiom the aquifei vn the main well which is connected to a pumping well via a bottom outflow μiovided with a iegulating valve to maintain a given level of water in the aquifei
iO Typically the main well is hi ought in contact with the sunoundinq atmosphere theioby avoiding any negative piessuie in the aquifei
typically watei is flushed out from said satellite wells into said ioaction zone in a ciiculai pattern to allow the ieaction zone to lecovei intermittently and to cieate a balanced working i^ pressure on the miciooiganisms acting in said /one Detailed description of the invention
I n particular the present invention relates to an artificial aquifer for decreasing the contents of metals, metalloids, nitrate, nitrite pesticides and organic micro contaminants in natural
5 ground water artificial infiltrated ground water from surface water and comprising a basin of filling material creating a reaction zone, a feeding line, one or more satellite wells at least one main well and a pumping well, characterized in that the feeding line is applied in the upper outer periphery of the basin and wherein the main well is connected to a pumping well via a bottom outflow provided with a regulating valve to maintain a given level
K) of water in the aquifer
The satellite wells may be arranged preferably in a circular pattern inside the feeding line
Typically raw untreated water ot untreated natural groundwater is now injected into the 1 5 plant, through its periphery thus creating a circular pool of watei in line with the circular arrangement of the satellite wells of the plant in the aquifer Also a number of satellite wells are used to keep the reaction zone in a habitable form foi optimal environmental living conditions foi the relevant microoi ganisms
?( ) A furthei aspect of the invention i elates to a method foi decreasing the contents of metals metalloids niti ate nitrite pesticides and oi ganic micr o contaminants in natural ground watei Ot artificial infiltrated gr ound watei ti om suiface watei using an artif icial aquifei whereby the watei to be pi ocessed is infilti ated into a basin of filling material ci eating a i eaction /one thi ough a feeding line pi ocessed in one or more satellite wells and passed
} ^ to at least one main well and a pumping well whoi eby the feeding line is applied in the upper outei peπphei y of the basin thei eby avoiding so called dead zones in the aquifer and pi oviding for a higher degree of purification and wheieby watei having been puufied is withdrawn from the aquifei via the main well which is connected to a pumping well via a bottom outflow pi ovided with a i egulating valve to maintain a given level of water in the iθ aquifer
The main well may be bi ought in contact with the sui i ounding atmosphere thereby avoiding any negative pr essure in the aquifer
"1 O The present invention will be described moi e in detail in the following with reference to the attached drawing showing a preferred embodiment of the invention wherein FIG 1 shows a cioss sectional view of an aquifer of the invention
FIG 2 shows a view fiom above of the aquifer according to FIG 1 and
FIG 3 shows a detail of the main well and the pumping well
S Thus the present invention relates to an artificially created basin completely filled with natuial washed oi unwashed matenal which is used foi the purification of giound watet The purification results in a decrease of the content of metals metalloids nitrate nitrite pesticides and oiganic sourced micio contaminations For the purification process ιaw ground water is fed into the basin thiough a peripheral infiltration line The raw giound
IO water passes on this way to the main well the so called reactive zone whereby oxygen oxygen ieleasing substances or natuial oiganic substances will be present This reactive zone provides the optimal envnonment for chemical and metabolic reactions by the natut ally occumng microorganisms The optimal environment in the reactive /one is maintained with the opeiation of the satellite wells The outflow of the purified watei from
I i the main well at the bottom to the pumping well allows to keep the aquifei always full with watoi named as can aitificial confined aquifei and no negative piessuie is ever piesent aiound the main well The invention i elates to an appaiatus foi canying out the method undei c onfined aquifoi conditions and seveial satellite wells and the combination of at lea^t one main well and foi at least one pumping woll
20
I he aquifer of the piesent invention consists of a basin 1 which is noimally dug into the giound and heie having a αiculai design seen fiom above and foiming a tiuncated cone seen in a cioss section theieof fhc- bottom of the basin is coveied with an impermeable sheet 2 to reduce loss of wntei fiom the basin Λ citculai initiation line 3 seiving as a
0 ^ feeding lino is jiiangod in close v ι inity to the outer and upper pet iphei y of the ba'-in 1 1 he basin 1 is filled with natuial washed oi unwashed material which is commonly used foi the puiification of giound watei Such matenal is noimally sand and giavel and forms the ieaction /one ' ■ > of the aquifei On the inside of the feeding tube line 3 satellite wolls 4 foiminq a ciiculai pattern aie ananged at a substantially equal distance from each othei
■ >{) The satellite wells A aie ananged voitical into the matenal The feeding line 3 consists of a perfoiated tube thiough which the watei to be processed is fed and piessed out into the ieaction /one
In the middle of the aquifer a vertical main well 6 is ananged which well b consists ot a
^-> perfoiated tube holding the filling material of the aquifei otrt but allowing water to penetiate into the well The main well is emptied via a pumping well 7 which communicates with the main well 6 via an outflow tubing 8 (seen in FIG 3) 1 he opening of the bottom outlet of the main well 6 to the pumping well 7 is controlled by a regulating valve 13 accordingly to maintain always a high level of water in the aquifer to optimize the growth conditions of the miciooiganisms The top of the main well 6 is covered with a non closing lid 9 which i allows the surrounding atmospheiic pressure to act on the watei level in the main well 6 theieby avoiding any negative pressure in the system
In the pumping well 7 one oi moie pumps (not shown) are aπanged to feed a transporting line (not shown) connected to the consumers housings industry facilities etc
K)
On the top of the aquifei an impermeable geomembrane 10 is applied or othei covei in older to avoid contaminations fiom above into the reaction zone of filling materials Any such contaminations may seriously disturb the activity in the ieaction zone if they should contain compounds that afflict the giowth of the microoiganism floia used to reduce oi
I "i oxidi/e the pioducts to get lid off A layei 11 of soil gravel or sand is then applied on top of the geomembiane 10 to keep that in place
A pιoces c eontiol unit (PCU) 12 is connected to the system to confiol the feeding in and out of waiei the intioduction of watei fiom ihe satellite wells A into the ieaction /one by
20 one oi moie neaiby satellite wells in a conti oiled mannei Noimally the intioduction is can ied out in a ciirulai pattern to allow ihe teaction /one to lecovei intei mitter illy and to cieate a balanced wotking piessuie on the miciooiganisms acting in the said /one the P( U \2 fuithei contiols the outflow of watei fiom the main well 6 via the pumping well 7 to the di&ti ibuiion line IT should be understood that the PCU 1? is placed in contact with the g ound watei supply
The artificial aquifei shown in the di awing may contain a volume of moie than 5000 cubic meteis having a iadius of moie than 30 meteis and a depth of 8 meteis oi moie Such an aquifei will IaJ foi many yeais and seive the population and industry aiound The capacity M) of the aquifoi pei 2Λ his is calculated to about 2500 cubic metei of puie watei ba c ed on a noimally used particle size of the filling matenal The capacity is calculated to last foi 100 yeais
Depending on the diameter of the aitificial aquifer which may vaiy Irom 5 to / meteis up to "} " • > 50 meteis in diametei oi mote the capacity will iange fiom 100ιn° 5000nτ7day Moie than one tawwatei well (withdrawing lhe ιawwateι from the aquifei/ aquifeis) can be used to withdiaw the water from the natural aquifer/ aquifers and supplying the watei into the feeding line into the artificial aquifei
^ More than one main well and pumping well (pioduction well) can be used to pump up the purified watei fiom the artificial aquifer
The raw giound watei passes on this way to the main well 6 the so called leactive zone 5 whereby oxygen oxygen-releasing substances oi natural organic substances will be
K) present theiein This reactive zone provides the optimal enviionment foi chemical and metabolic ieactions by the natut ally occuiπng micioorganisms The optimal environment in the reactive zone is maintained with the operation of the satellite wells A The outflow of the purified water fiom the main well at the bottom theieof to the pumping well allows to keep the aitificial aquifei always full with watet named as an artificial confined aquifei and no
1 -> negative piessure is evei piesent aiound the main well
The opeiation of the plant is that that ιaw untreated natuial gioundwatei oi aitificially infiltiated giound watei fiom suiface watei is mlϊltiatcd into the plant ihiough the hou/ontally aiianqed tubing just in the penpheiy of the plant to avoid /one c of non moving
'() watei (so called dead /ones) fhe tubing is heie ananged at a distance of less than 1 metei from the veiy outei penpheiy in an aquifei having a diamotei of 3b to 40 motets In case the atiific ial aquifei has a smallei diametei the tubing will bo c losei than 1 motei fiom the penphety such as Ob metei oi less to avoid any dead volume in the aquifei In a second innei paiallol aiiangement a numbei of satellite wells will be placed which aie used
^ to Ce ate the optima! envnonmenta! living condition^ foi he lelevant i"icιooιqanι c m in the centei of the plant is the main well situated which is used as a collecting well and without the use of any pump the watei is diiected to the adjacent pumping well / by the opening at the bottom of the main well I his enable the opeiatoi to maintain the aquifei in a confined status and no negative piessuie will evei occui and due to this all mateiidl within the i() aquifei is full soaked in watei lhe opening of the bottom outlet to the pumping well / is conti oiled by a regulating valve accoidingly to maintain always a high level in the aquifei The main level is coveied by an impeimeable geomembiane oi othei matenal and the top of the well is open to atmospheiic changes and therefoie the aquifei is not completely tight oi the lemoval of paitic les such as in dusty aieas an aiitiltet can be placed in the top
I^ construction of the main well The pumping well is equipped with a pump and a level contiol device Thus the feeding line 3 is placed at a distance from the oulei periphery that is less than 1 /40 th of the diameter of the aquifer, preferably less than 1 /50 th of the diameter preferably less than 1 /60 lh of the diameter, and more preferably less than 1 /100 1 ' 1 of the diameter 5
The main claims of this invention is that the plant is operating avoiding any so called dead zones does not need a hermetically sealing on the top due to controlled outflow which keeps the aquifer always as a confined aquifer in operation and that we will not apply any negative pressure around the main well The arrangement of the aquifer can be in any 1 0 form
The design of the artificial aquifer above has been shown as a circulai basin while it is apparent that any form can be used, sometimes the form is predicted by the natural surroundings and what they will allow Thus the artificial aquifer may be circulai oval 1 5 hexagonal octagonal or take any form dictated by the surrounding terrain
Advantages
1 No negative pi essure means The system disclosed in accoi dance with the cui tent invention does not have any drawdown of watei which pi ovides a bettei use of the filling
20 material and a lowei and more constant entrance velocity of the watei into the main well which reduces the risks of blocking the main well with small gi ains di astically
2 No dead /ones means T he system disclosed in accordance with the cui i ent invention does not have zones whei e watei is always standing and unconti olled baotei ial gi owth can happen which would destroy the water quality
J 1 ") 3 No hci mctic closing is needed to avoid negative pi essui o ai ound the main well
A The use of a main well together with a so called pumping well in accoi dance with the system disclosed in the current invention secures during the opei ational time of the ai tificial aquifei always the same water velocity and therefore a much bettei peifoi mance in teuns of filtr ation and genei al cleaning effects