FI128716B

FI128716B - Apparatus for remediation of subterranean substrate, related system and method

Info

Publication number: FI128716B
Application number: FI20185618A
Authority: FI
Inventors: Mikko Myllymäki; Petri Koikkalainen
Original assignee: Doranova Oy; Geomachine Oy
Priority date: 2018-07-04
Filing date: 2018-07-04
Publication date: 2020-10-30
Also published as: FI20185618A1

Abstract

A direct push injection apparatus (10) for remediation treatment of contaminated subterranean substrate is provided, said apparatus comprising a dual drill rod arrangement, wherein an inner drill rod (2), disposed within an outer drill rod (1), comprises a drill bit (12) with a substantially blind leading end incorporating a number of injection nozzles (14) and cutting elements (13). The apparatus allows for injection of fluids into substrate directly during drilling a wellbore, thereby replacement of a bore drill bit by an injection grout is avoided. Related direct push injection system and a remediation method are further provided.

Description

APPARATUS FOR REMEDIATION OF SUBTERRANEAN SUBSTRATE, RELATED SYSTEM AND METHOD

FIELD OF THE INVENTION The present invention generally relates to drilling- and injection equipment for on-site restoration of polluted subterranean substrates. In particular, the present invention concerns a direct push injection technology based apparatus and system for delivering remediation reagents into the subsurface, and a related method.

BACKGROUND Cleanup and restoration of polluted subterranean substrates, such as soil and groundwater, isa well-recognized necessity at present and in coming decades. A plentiful of harmful products that are intentionally or accidentally poured into soil and potentially penetrated into groundwater includes volatile and semi-volatile organic compounds, petroleum hydrocarbons, pesticides, corrosives, inorganic compounds such as lead, chromium, cadmium, arsenic, mercury, and radioactive compounds, such as radon and/or tritium, for example. A particular challenge and concern arises from cleaning up polluted areas unsuitable for restoration by excavation and physical transfer of soil bulk away from the contaminated site. In fact, sites of special concern include a vast majority of urban, industrial and farmland areas, such as factories, related stockpiles and holding areas, landfills and waste disposal sites, refueling stations, highways, urban parking lots, heavy traffic spots, airports, household sites, animal rearing facilities, and the like. In order to effectively deal with the above identified problem a variety of site-specific (in- situ) procedures has been developed. Conventional in-situ methods include pre- S establishing a number of fixed vertical wells for injection and for monitoring / extraction N 25 and optionally a number of horizontally interconnected lines disposed underground. 3 Delivery of remediation reagents and chemicals into such wells is implemented by means N of injection pumps and other appropriate installations. In many instances such installations z are permanent or at least not readily dismountable. a 00 Still further branch of subterranean remediation technologies, applicable, among others, for O 30 on-site restoration, is based on so called Direct Push (DP) injection methods, in which > drilling and injection of remediation chemicals into soil are integrated. Conventional DP installations utilize injection tools configured as probe rods with injection ports at a leading end. Injection tool is typically associated with a hydraulically operated machine for driving the probe rod into soil.

After the probe rod has been pushed into the subsurface, injection is completed through the ports.

Known DP probe systems include pressure-activated injection tools and retractable sleeve injection tools.

In pressure-activated systems the probes incorporate an internal check valve to prevent clogging otherwise uncovered ports; thereby the ports are shut while the probe rod is pushed to depth.

Retractable sleeve systems are designed such as to keeps the ports inside the injection tool upon pushing; thereafter the upper part of the tool is retracted upwards thus exposing an internal injection port section.

As a rule, conventional DP injection tools are provided with a solid tapered tip.

However, existing DP installations have only proved effective in reclamation of soft, sandy or clayey lands substantially void of rocks.

In moraine lands, for example, use of conventional DP equipment is impossible.

Moreover, use of said conventional DP devices on deteriorated rocky areas is precluded.

In an event when the above described DP injection tool hits the rock, the entire system normally halts; however, in most severe instances irreparable damaging of the probe may occur.

Thus, existing DP solutions are not applicable in Finland, for example, because of lands being predominantly rocky and/or of moraine origin.

It is clear that removing rocks from the subsurface within an entire reclaimable area is far from being labour- and cost-effective.

US 2015/0314344 (Perpezat et al) discloses an apparatus for treating portions of soil to improve some of its mechanical, physical and chemical characteristics.

The apparatus comprises an inner rotary shaft with a drilling tool at its end, such as a three-blade drilling bit, for example, and an outer tubular element.

The outer tubular element advances in the soil by virtue of being linked to the inner drilling tool and forms a protective case for the inner drilling tool.

US 4,074,779 (Cheung et al) discloses a hydraulic borehole mining device configured as o 25 an elongate body with jet nozzles for injecting high-pressure liquids into the substrate and S a drill bit for reduction of over-sized substrate particles.

S US 5,069,725 (Fischer et al) discloses an apparatus for cleaning underground substrate by N (direct) injecting cleaning liquid into said substrate.

The apparatus comprises a drilling E tube that comprises an inner tube provided with a drill bit and an at least one nozzle.

The © 30 inner tube is surrounded by an outer tube.

Mentioned inner and outer tubes are sealed off o relative to one another. 00 > WO 2017/219792 A1 (Yang et al) discloses an in-situ injection system for remediation of soil and ground.

The system comprises a high-pressure jet drill pipe with an inner tube and an outer tube, and a drill bit mounted with the drill pipe.

Additionally, CN 102671932 A

(Yang et al) provides for in-situ remediation method, in which injection fluid is hot-air. The method utilizes a hot air jet pipe integrated inside a drill pipe with a drill bit. Although providing a drill bit with a number of injection nozzles is a conventional technique in injection devices which remediate contaminated subterranean substrate, none of the abovementioned documents teaches or suggests provision of the drill rods as entities with independent drilling functions. For the above identified reasons said conventional DP solutions are unsuitable for use on the industrial / manufacturing sites having rocks and concrete blocks in their foundation / an artificial landfill, as well as in the areas laid with pavement (e.g. asphalted), such as airports, highways or refill stations. Additionally, DP injection tools and associated installations currently available on the market, such as GeoProbe solutions, for example, are rather costly due to specifically tailored design thereof, with an average price of 300 Keur per installation. In this regard, update on the field of the Direct Push injection technology and its use in remediation of contaminated lands is still desirable, in view of addressing the problem of cleaning up very dense, rough and/or rocky lands and/or subterrains within industrial- and urban areas.

SUMMARY OF THE INVENTION An objective of the present invention is to solve or at least mitigate each of the problems arising from the limitations and disadvantages of the related art. The objective is achieved by various embodiments of an injection apparatus for remediation treatment of contaminated subterranean substrate, related system and method. Thereby, in one aspect of N the invention an injection apparatus is provided, according to what is defined in the N 25 independent claim 1. 3 N In one preferred embodiment the injection apparatus comprises an outer drill rod r configured as an elongated tubular body with a drill bit mounted at a forefront thereof, said E drill bit having an open leading end, and an inner drill rod configured as an elongated 2 tubular body with a drill bit mounted at a forefront thereof, said drill bit having an O 30 essentially blind leading end provided with a number of injection nozzles, wherein the > inner drill rod is disposed within the outer drill rod.

In some embodiments, the injection apparatus is configured such, that the inner drill rod further comprises a fluid supply line to convey fluid therethrough towards the related drill bit. Each drill bit is preferably configured detachable from the corresponding drill rod. In further embodiments, the drill bit mounted at a forefront of the inner drill rod further comprises a plurality of cutting elements at the leading end thereof. It is preferred that each drill rod provided within the injection apparatus is regulated independently from one another. In some embodiments the injection apparatus further comprises a suction appliance, thereby substrate obtained upon drilling is conveyed upwards through a gap formed between an inner surface of the outer drill rod and an outer surface of the inner drill rod. In some embodiments, the injection apparatus is configured such that the drill rods are each configured to establish a hammering percussion motion or a rotary-percussion motion upon advancement into substrate. In another aspect of the invention an injection system is provided according to what is defined in the independent claim 8. In preferred embodiment the system comprises the apparatus according to the previous aspect and a mobile drilling platform comprising a carrier vehicle and a telescopic drilling mast. In some embodiments, the system further comprises a hydraulic engine configured to drive the drill rods of the apparatus into the substrate and out of the substrate. In some other embodiments, the system further comprises an injection unit configured as a S cart connectable to the mobile drilling platform. & o In some embodiments, the system is configured to deliver fluid from the injection unit to

O N the fluid supply line provided within the inner drill rod of the injection apparatus. E 25 In a further aspect of the invention a method for remediation treatment of contaminated © subterranean substrate is provided according to what is defined in the independent claim o 12. The method preferably comprises: (a) provision of an injection system comprising the © injection apparatus according to some previous aspect, a mobile drilling platform and an

O N injection unit; (b) establishing a motion of the inner drill rod and/or the outer drill rod into substrate, thereupon a first fluid is conveyed into substrate through the inner drill rod and the related drill bit; (c) upon reaching a desired depth, terminating said motion and said fluid supply; and (d) establishing supply of a second fluid into substrate through the inner drill rod and the related drill bit, wherein said second fluid is a remediation reagent. The said first fluid is preferably water or air. In some embodiments, said first fluid and/or said second fluid are conveyed under pressure.

5 In some embodiments, the method comprises conveying the substrate obtained upon drilling upwards through a gap formed between an inner surface of the outer drill rod and an outer surface of the inner drill rod of the apparatus into a collection reservoir provided within the mobile drilling platform.

In further embodiments, the method comprises, in between items (c) and (d), provision of a — first sealing arrangement around the outer drill rod on a ground surface and provision of a second sealing arrangement in the gap formed between the outer- and inner drill rods. In still further aspect of the invention, use of the injection apparatus, according to one of the previous aspects, is provided for remediation treatment of contaminated subterranean substrate within a predetermined area, wherein said substrate is an essentially rocky substrate and/or said substrate is laid with pavement. The utility of the present invention arises from a variety of reasons depending on each particular embodiment thereof. At first, the invention provides for a simple, in terms of required machinery, and cost- effective direct push injection solution for restoration of contaminated sites regardless of substrate (soil) type thereof. In particular, the invention allows for efficient restoration of coarse rocky substrates, such as moraines. Innovative dual rod design of the direct push injection tool, the present invention provides for, enables drilling wellbores even through o the rock and allows for subsequent injecting remediation reagents into substrate without O changing a drill bit, otherwise used for boring, for an injection probe. In an event a site to o 25 be restored consists of essentially loose, e.g. sandy, substrate, the apparatus provided = hereby enables conversion of the dual rod arrangement to a single rod arrangement, N thereby drilling and injection can be accomplished by means of a merely inner drill rod. E Still, flexible design of the apparatus enables mounting of the outer drill rod onto a related © drill chuck arrangement directly on-site, which is particularly useful when the site to be O 30 restored combines both sandy/clayey and rocky soil substrates. S Moreover, the apparatus of the invention provides for successful restoration of subterranean substrates disposed at sites occupied by buildings and/or open areas laid with pavement. By means of the apparatus and the system provided hereby, injection of remediation reagents under the subsurface can be performed on-site without tearing off the pavement. This enable remediation treatment of substrates disposed under a variety of otherwise difficult-to-reach objects, such as highways, airports and/or refill stations, for example.

Due to its compact size, an entire direct push injection system, provided hereby, can be further driven inside the building, such as a factory facility, for example; placed in a backyard of a private household, or in a farmyard. Moreover, the system can be exploited for injecting remediation reagents into already existing wells, such as monitoring wells established for conventional in-situ remediation procedures, for example.

The invention further provides for a mobile injection unit, provided within the system and embodied as a wheeled cart towable by a conventional motor vehicle, for example. Said injection unit is fully autonomous and contains, among other things, means for generating power, injection pump(s), and means for preparation and mixing of remediation reagents. In this regard, the invention provides for a mobile, self-contained entity for restoration of contaminated subterranean substrates, which leaves no noticeable traces during the treatment and thereafter, which requires no additional transportation means within the area to be remediated, and whose operational performance can be adjusted directly on-site, thereby no permanently fixed installation(s) is required.

The expression “a number of” is used in the context of the present document to indicate any positive integer starting from one (1). The expression “a plurality of? refers hereby to any positive integer starting from two (2), e.g. to two, three, or four.

The expression “remediation treatment” is used hereby to indicate a set of actions directed to any of removal, breakdown and/or neutralization of contaminants present in S environmental] media and generally having negative impact on human health and N 25 environment. The expression “subterranean substrate” is utilized hereby to indicate any 2 kind of substrate or medium, e.g. solid or fluidic, occurring beneath the ground surface. The term “drilling” is used hereby to indicate a process of material removal from the E subsurface upon creating a wellbore in the (ground) substrate. The term “drilling” is used © in the present discloser as an equivalent to the term “boring”. © o 30 Different embodiments of the present invention will become apparent by consideration of S the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 schematically illustrates an injection apparatus 10, according to some embodiments. Fig. 2 illustrates drill bits for an inner- and outer drill rods provided within the injection apparatus 10, according to some embodiments. Fig. 3 schematically illustrates an injection system, according to some embodiments. Fig 4 illustrates an injection unit for the injection system, according to some embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS Detailed embodiments of the present invention are disclosed herein with the reference to accompanying drawings. The same reference characters are used throughout the drawings to refer to same members. Following citations are used for the members: 10 — an injection apparatus, 1 — an outer drill rod, 2 — an inner drill rod, 3, 3A — sealing arrangements, 4 — a gap formed between the drill rods 1, 2, 5 — a fluid supply line within the inner drill rod 2, 5A — fluid supply channels within the drill bit 12, 11, 11A — an outer drill bit and a crown thereof, 12, 12A — an inner drill bit and a crown thereof, 13 — cutting elements, 14 — injection nozzles, 20 — a mobile drilling platform, 21 — a carrier vehicle, 22 — a drilling mast, 23 — a hydraulic engine, < 25 24 — a collection reservoir, O K . N 30 — an injection unit, 3 31 — an injection pump, N 32 — storage and/or mixing reservoir, N 33 — a mixing arrangement, I . g 30 34 — a power generator / a machine aggregate, © 40 — ground surface, o 41 — rock, © 42 — subterranean contamination, S 43 — waste substrate, 51,52 — first- and second injection fluids, accordingly.

Fig. 1 schematically illustrates a concept underlying different embodiments of an injection apparatus 10 for remediation treatment of contaminated subterranean substrate (hereafter, “substrate”). Subterranean contamination that occurs under the ground surface 40 is schematically indicated on Fig. 1 by a reference numeral 42.

The apparatus 10 is configured as a direct push injection apparatus. Direct push injection technology, in the present disclosure, is defined as a process associated with inserting a fluid injection tool into the subsurface directly upon drilling a wellbore.

The apparatus 10 is provided with a dual drill rod arrangement 1, 2, comprising an outer drill rod 1 and an inner drill rod 2, wherein the inner drill rod 2 is disposed within the outer drill rod 1 such that an empty space or a gap 4 is established between an inner surface of the outer drill rod 1 and an outer surface of the inner drill rod 2. Provision of the inner rod 2 within an interior of the outer rod 1 is such that the dual rod arrangement forms, at its’ cross-section, a round O-ring. Each drill rod 1, 2 is configured as a hollow, elongated, tubular body with a cylindrically shaped housing. At a forefront of each drill rod a drill bit (a drill head) is further mounted. Said drill bits are configured detachable from the corresponding rods 1, 2 to enable replacement of the individual drill bit in case of its wearing out or damage. At its rear (hereby, an uppermost part of the drill rod), each drill rod 1, 2 is provided with appropriate connectors or adaptors, preferably (male) thread connectors / adaptors, to engage with a chuck of a drill mast, as described further below. In terms of length, each drill rod 1, 2 is preferably provided within a range of about 40 — 250 cm; however provision of rods whose length exceeds said 250 cm is not excluded. In terms of diameter, parameters for the outer drill rod 1 constitute about 10 — 30 cm, and for o the inner drill rod about 5 — 20 cm. N 25 With reference to Fig. 2, the outer drill rod 1 is eguipped with a so called core drill bit 11 2 configured as an essentially barrel-shaped, hollow, open-ended member with a shaft and a N profiled flange 11A (a “crown”), which constitutes a leading end of the drill bit. The drill I bit 11 advantageously comprises a plurality of cutting elements physically embedded- or - mounted onto the crown. In some configurations the crown 11A can incorporate a single = 30 “cascade” of cutting elements forming a cutting edge of said crown. In some alternative 0 configurations the cutting edge can be formed by a number of cascades established by a > corresponding number of (circular) flanges with cutting elements arranged thereon. An outermost flange of such cascaded cutting edge is the largest in terms of the diameter, whereas an innermost flange is the smallest. The drill bit 11 for the outer rod is configured as a merely drilling bit with an open-end leading end; therefore, an overall design and associated materials of said bit largely depend on the characteristics of excavated substrate.

The inner drill rod 2 is, in turn, equipped with a drill bit 12 comprising a shank and a crown 12A.

The crown 12A is configured such, as to form an essentially blind leading end of the drill bit 2. At its crown, the drill bit 12 further incorporates a number of injection nozzles 14 (Fig. 2). Configured of the drill bit 2 is such, as to allow its’ unobstructed movement through the outer rod 1 and through the related drill bit 11. It is preferred that the drill bit 12 comprises two or more injection nozzles 14. In a latter case the injection nozzles are preferably evenly distributed through the entire surface area of the crown 12A to allow for uniform injection rates into surrounding substrate.

The drill bit 12 further comprises a number of channels SA, optionally arranged into a network, to convey fluid therethrough towards the injection nozzles 14. In preferred configurations the injection nozzles 14 are provided as essentially circular or tapered recesses (ports) on the surface of the crown 12A integrally connected to the internal channel network SA.

Still, any other feasible configuration can be alternatively utilized.

In terms of functionality, the injection nozzles can be configured as spray nozzles or jet nozzles, for example.

The latter configuration is particularly suitable for injecting pressurized fluids into subterranean substrate; thereby fluid penetration distance can be markedly improved.

The drill bit 12 further comprises a plurality of cutting elements 13 physically embedded or mounted onto the crown 12A (Fig. 2). Said cutting elements are advantageously provided as prominent profiles including, but not limited to: cones, truncated cones, solid and staged S pyramids, and (hemi)spheres.

An exemplary embodiment of the drill bit 12 shown on Fig.

N 25 1 should not be understood as limiting; instead, the present disclosure is meant to 2 encompass a variety of plausible combinations with regard to an extent of the cutting N elements 13 and the injection nozzles 14, and arrangement thereof on the crown 12A.

E The drill bit 12 can be further provided with a number of sensor devices (not shown) for © monitoring a variety of apparatus- and substrate-related parameters, such as temperature, O 30 pressure, resistance, drilling speed, soil acidity and pH; as well as for detecting and S monitoring the presence of individual contaminants in the substrate.

Provision of the apparatus 10 is such that advancement of the dual rod arrangement into substrate is accompanied by injection of fluid into said substrate via the injection nozzles

14 provided within the interior drill bit 12. Fluid injection can be continuous or in pulses.

The apparatus 10 thus comprises, within the inner drill rod 2, an at least one fluid supply line 5 (Fig. 1), to convey fluid therethrough toward the related drill bit 12. Said fluid supply line 5 establishes direct fluid communication with the channels SA provided within the related drill bit 12, thus allowing for unobstructed delivery of fluid(s) into substrate.

Said fluid supply line is advantageously embodied as a channel or a pipe suitable for conveying fluids under pressure.

In the apparatus 10, each drill rod 1, 2 is preferably regulated independently from one another.

Individually regulated parameters thus include, but are not limited to: drilling speed and/or rotary speed, thrust, torque, and percussion frequency.

Additionally, reciprocal motion of the rods 1, 2 (into the substrate and out of the substrate) can be implemented simultaneously or separately.

In some instances, it is advantageous that advancement of the drill rods 1, 2 into substrate is synchronized at least in terms of speed.

In preferred configurations, advancement of the drill rods 1, 2 into substrate and out of the substrate is mediated by a hydraulic engine provided within an injection system described further below.

In preferred embodiments, the apparatus 10 is configured such that the drill rods 1, 2 provided within the dual rod arrangement are each configured to establish, upon advancement into substrate, a hammering percussion motion or a rotary-percussion motion.

Hereby, both drill rods can be configured to advance into substrate by series of hitting (hammering) movements causing “pushing” of said rods into the subsurface.

The apparatus 10 can be further configured such that the inner drill rod 2 advances into substrate by establishing said hammering percussion motion or a rotary-percussion motion; whereas the outer drill rod 1 establishes a merely rotary motion.

N 25 An overall design of the apparatus 10, in terms of selecting appropriate configurations for N each of the drill rods 1, 2 and related drill bits 11, 12, largely depends on a number of <Q external parameters.

Decisive factors, include, inter alia, nature of the site to be remediated N (i.e. industrial facility, farmland, private household, etc.), landscape of said site, type of the E deteriorated substrate (rock, silt, sand, etc.), and/or provision of groundwater or aguifers in © 30 the substrate subject to remediation treatment. he The apparatus 10 further comprises a suction appliance (not shown) to convey outflowing > (“waste”) substrate 43, obtained upon drilling a wellbore, in an upward direction outside the wellbore (i.e. onto the ground surface). Such waste substrate is conveyed through a gap 4 formed between an inner surface of the outer driving rod 1 and an outer surface of the inner drill rod 2. In an alternative embodiment, said suction appliance may be provided within an injection system, described herein below.

Fig. 3 schematically illustrates exemplary embodiments of an injection system, according to another aspect of the invention.

The system is configured as a direct push injection system, accordingly.

The system advantageously comprises the apparatus 10 according to the previous aspect, and a mobile drilling platform 20 comprising a carrier vehicle 21 and a drilling mast 22 mounted onto said carrier vehicle.

The mobile drilling platform is preferably realized on the basis of continuous track vehicle, such as a small-sized excavator (10 — 18 tons) or a mid-sized excavator 20 — 35 tons). In some instances, utilization of a heavier machinery (exceeding 35 tons) is not excluded.

In some other instances the drilling platform may be realized on the basis of a wheeled vehicle.

The carrier vehicle 21 thus carries the drilling mast 22 preferably realized as a telescopic mast.

The telescopic drilling mast is preferably collapsible such that in a fully folded position (transportation position) it rests horizontally on the carrier vehicle.

To mediate folding, the telescopic mast is equipped with an at least one articulated joint.

Provision of the mast on the carrier vehicle can be implemented on a permanent or a temporary manner.

When the mast is in a vertical position (operating position), it is preferred that an angle of inclination thereof does not exceed 10 degrees.

Connection between the drilling mast 22 and the apparatus 10, in particular, the dual rod arrangement 1, 2 thereof, is established by a drill chuck or a mandrel (not shown), by means of appropriate connectors.

In exemplary embodiments the drill chuck equipped with a (female) thread connector(s) is configured to receive the drill rods 1 and 2 each equipped with a male thread connector / adapter, accordingly (not shown). An engine 23, preferably a hydraulic engine, is further provided on the mobile drilling N 25 platform 20 in connection with the drilling mast 22. By means of said engine the drill rods N 1, 2 are driven into the substrate, thereupon a wellbore is drilled, and out of the substrate. <Q The hydraulic engine provides mechanical force to mediate reciprocating movement of the N drill rods 1, 2 and mediates independent movement of each said rod into the subsurface, as E described herein above.

In some configurations, independent motion of the rods 1, 2 is © 30 mediated by a number of hydraulic flow control appliances, such as flow control valve(s) o and/or pressure relief valve(s). 00 > It is further advantageous to dispose a number of collection reservoirs 24 on the mobile drilling platform 20 for collecting outflowing substrate 43 delivered on the ground surface from the wellbore during advancement of the drill rods 1, 2 into the subsurface.

Such

“waste” substrate obtained upon drilling is conveyed upwards through a gap 4 formed between the rods 1, 2 by means of the suction appliance provided at the apparatus 10 or within the mobile drilling platform 20. In some instances an additional T-junction or Y- junction element can be provided (now shown) to enable and/or to facilitate simultaneous distribution of outflowing substrate 43 into a number of collection reservoirs 24. In preferred configurations, the system further includes an injection unit 30 configured as a cart physically and functionally connectable to the mobile drilling platform 20 (Fig. 4). The cart 30 is preferably a wheeled cart implemented on the basis of a standard trailer van (about 6 m in length and weight within a range of 700 — 3500 kg) configured to be towed by a conventional motor vehicle. In Europe, for example, such trailer van can be driven by a holder of BE driving license.

Once the injection system is delivered to the remediation site, the injection unit 30 is preferably towed by the carrier vehicle 21 provided within the mobile drilling platform 20. The injection unit 30 is fully autonomous; in some particular embodiments functionality thereof is maintained by a standalone power generator or a machine aggregate 34. Said injection unit is further adapted for wintertime use, by provision of appropriate insulation and/or heating means therein. In preferred embodiments, the injection unit 30 comprises, among others, an injection pump 31, a number of storage- and/or mixing reservoirs 32, an at least one mixing arrangement 33, and a control unit (not shown).

The reservoirs 32 are preferably configured for storage, dilution and/or mixing of a variety of remediation reagents including, but not limited to: hydrogen-release compounds (HRC), oxidants, nutrients, biostimulants, and/or other additives.

An injection pump 31 is preferably configured as a high-pressure pump applicable for S injecting a variety of fluids into wellbores. In some exemplary embodiments, maximum N 25 pressure capacity of the injection pump is about 10 MPa (100 bar). By means of said 2 injection pump functional connection is established between the injection unit 30 and the N apparatus 10, thereby fluid is delivered from the injection unit 30 (e.g. from any one of the I reservoirs 32) to the fluid supply line 5 provided within the inner drill rod 2 of the - apparatus 10 for further propagation into substrate via injection nozzles 14 provided on the = 30 drill bit 12. Said functional connection is schematically indicated, on Fig. 3, by a double- o head arrow.

N In some instances, said injection pump 31 is exploited for high-pressure hydrofracturing of substrate. Hydrofracturing is particularly helpful in processing rough substrates (e.g. silts or coarse clays) and/or rocky substrates.

The process involves the high-pressure injection of fluid (typically water) into substrate during drilling wellbores.

The injection unit 30 further comprises a control unit (not shown) configured for monitoring and regulating a variety of parameters related to injection and, optionally, drilling.

The control unit is thus configured to regulate functionality of the injection pump 31, thereby such parameters, as amount of remediation reagent(s) in relation to pressure, fluid flow velocity, can be adjusted.

The control unit can be further configured to at least partially regulate functionality of the hydraulic engine provided within the mobile drilling platform 20 and the drilling mast 22, and/or the independent reciprocal movement of the drill rods 1, 2. A method for remediation treatment of contaminated subterranean substrate, according to another aspect of the invention is described next.

The method starts at provision of an injection system comprising the apparatus 10, a mobile drilling platform 20 and an injection unit 30. The injection unit 30 (embodied as a cart or a van) towed by the carrier — vehicle 21 is thus driven to a predetermined location within a remediation site.

Locations for establishing wellbores for direct push injection are advantageously determined during preliminary landscaping of potentially contaminated area and creating a 3D model thereof.

Once the injection system has been delivered to the predetermined location, and the drilling platform 20 has been firmly installed on the ground surface 40, the method continues by establishing a motion of the inner drill rod 2 and/or the outer drill rod 1 provided within the dual rod arrangement of the apparatus 10, into substrate.

Advancement of the drilling rod(s) into the subsurface is accompanied by conveying fluid into substrate through the inner drill rod 2 and the related drill bit 12. Clogging of injection nozzles 14 is thus prevented by continuous injection of fluid during drilling and/or by provision of the > 25 outer drill rod 1 that acts, in some instances, as a protective shield for the inner rod 2. a Upon advancement of said dual rod arrangement into substrate (thereby a wellbore is <Q formed) it is preferred that a first fluid 51 is supplied into the subsurface (Fig. 1). Said first N fluid is preferably water, however, in some instances said first fluid may be air, preferably E compressed air.

In some instances, such as during hydrofracturing of rocks 41, for © 30 examples, water is also delivered under subsurface under high pressure. he Once the desired depth has been reached (based on data obtained from a preliminary 3D > modeling study of a potentially contaminated site, for example), the dual rod arrangement is set still and supply of the first liquid 51 is terminated.

At this point the wellbore is prepared and the dual rod arrangement is disposed inside said wellbore ready for injecting remediation reagent(s). Since the apparatus 10 combines, within the inner drill rod 2, drilling- and injection functionalities, the process described herein does not require replacement of a drilling bit (i.e. a bit solely designed for boring wellbores) by an injection grout. Withdrawal of any one of the drill rods 1, 2 out of the wellbore is also avoided. In most instances it is, however, advantageous that the outer drill rod is driven 10 — 50 cm upwards, as shown on Fig. 1, to expose the crown 12A of the “inner” drill bit 12 containing injection nozzles 14 thus facilitating injection of remediation reagent(s) to the surrounding medium (aka contaminated substrate 42).

Prior to initiating injection of remediation reagents, it is desirable to safeguard the entire installation from leaking out. Hence, a first sealing arrangement 3 is provided around the outer drill rod 1 on the ground surface 40, and a second sealing arrangement 3A is provided in the gap 4 between the outer- and inner drill rods 1, 2 (Fig. 1). The first sealing arrangement 3 is preferably an insulation plate, such as a metal plate, for example, and it is preferably installed prior to initiating drilling of the wellbore. The second sealing arrangement 3A is installed inside the gap 4 after the predetermined depth has been reached by the drill rods 1, 2 and prior to initiating injection of remediation reagent(s). During advancement of the drill rod(s) into the subsurface the gap 4 remains sealing-free to allow unobstructed removal of outflowing substrate 43 from the wellbore.

The second sealing arrangement 3A may be configured as a conventional annular seal, for example, that prevents remediation chemical(s) from leaking out. In some alternative embodiments, the second sealing arrangement may comprise a hydraulic sealing element or elements commonly utilized in hydraulic cylinders. Sealing arrangement 3A may be further selected such as to enable movement of the inner drill rod 2 while the outer drill rod 1 is set still. By provision of the sealing arrangements 3, 3A within the apparatus 10, S leakage of remediation reagent(s) (injected under pressure) onto the ground surface is S avoided.

3 N The method continues hereafter at establishing supply of a second fluid 52 into substrate N through the inner drill rod 2 and the related drill but 12, wherein said second fluid 52 is E 30 advantageously a remediation reagent. The expression “remediation reagent” is used in the © present disclosure in its broadest sense; thereby it should be understood as incorporating O any kind of chemical or biological reagent generally utilized in remediation treatments, or S a mixture of said reagents, said reagent or a mixture thereof being optionally diluted in an N appropriate solvent.

In preferred embodiments, the second fluid 52 is conveyed into the subsurface under pressure. Preparation of said fluid 52 (a remediation reagent), in terms of diluting and/or mixing thereof, is performed in the injection unit 30, in at least one of the reservoirs 32; therefrom said second fluid is guided to the apparatus 10 via the injection pump 31 and appropriate pipelines or hoses. Such pipelines and hoses utilized for connecting fluid reservoirs within the injection unit 30 with the fluid supply line provided within the inner drill rod 2 of the apparatus 10, are implementable based on installations generally known in the art; thereby their further description is omitted.

In some embodiments, the method further comprises conveying substrate 43 obtained upon — drilling upwards through a gap 4 formed between an inner surface of the outer drill rod 1 and an outer surface of the inner drill rod 2 of the apparatus 10 into a collection reservoir 24, provided within the mobile drilling platform 20. Removal of such outflowing substrate from the wellbore is thus implemented by means of the suction appliance (not shown).

The direct push injection apparatus 10 and the related system described hereinabove can be advantageously utilized for performing on-site restoration of subterranean substrates within contaminated areas of any kind regardless of the substrate (soil) type. Nevertheless, the apparatus 10 and the related system are particularly suitable for use in areas with essentially rocky substrate and/or in the areas, in which said substrate is laid with pavement.

Impact area of the direct push injection apparatus 10 constitutes 3 — 15 meters therearound. Comparatively small impact area (e.g. in comparison with conventional in-situ arrangements, whose impact area may exceed 100 m), is compensated by simplicity of installation and possibility for reaching potentially contaminated areas unreachable by conventional in-site and/or direct push methods and associated equipment. One of the most o 25 prominent advantages of the apparatus and system disclosed hereby is compactness and | unobtrusiveness, which allowing for restoration of contaminated subterrain in industrial 2 and densely inhabited areas in an almost untraceable manner.

N It is clear to a person skilled in the art that with the advancement of technology the basic E ideas of the present invention are intended to cover various modifications and eguivalent © 30 arrangements generally encompassed within the present disclosure. The invention and its o embodiments are thus not limited to the examples described above; instead they may = generally vary within the scope of the appended claims.

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Claims

1. An injection apparatus (10) for remediation treatment of contaminated subterranean substrate, the apparatus comprising: - an outer drill rod (1) configured as an elongated tubular body with a drill bit (11) mounted at a forefront thereof, said drill bit (11) having an open leading end, and - an inner drill rod (2) configured as an elongated tubular body with a drill bit (12) mounted at a forefront thereof, said drill bit (12) having an essentially blind leading end provided with a number of injection nozzles (14), wherein the inner drill rod (2) is disposed within the outer drill rod (1), and wherein the movement of each drill rod (1, 2) in the subterranean substrate is independent on one another.

2. The apparatus of claim 1, wherein the inner drill rod (2) further comprises a fluid supply line (5) to convey fluid therethrough towards the related drill bit (12).

3. The apparatus of any preceding claim, wherein each drill bit (11, 12) is configured detachable from the related rod (1, 2).

4. The apparatus of any preceding claim, wherein the drill bit (12) mounted at a forefront of the inner drill rod (2) further comprises a plurality of cutting elements (13) at the leading end thereof.

5. The apparatus of any preceding claim, wherein each drill rod (1, 2) is regulated independently from one another.

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6. The apparatus of any preceding claim, further comprising a suction appliance, thereby D substrate (43) obtained upon drilling is conveyed upwards through a gap (4) formed

N N between an inner surface of the outer drill rod (1) and an outer surface of the inner ? 30 drill rod (2).

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7. Theapparatus of any preceding claim, wherein the drill rods (1, 2) are each configured © to establish a hammering percussion motion or a rotary-percussion motion upon O advancement into substrate.

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8. An injection system, comprising the apparatus (10) as defined in any one of claims 1- 7, and a mobile drilling platform (20) comprising a carrier vehicle (21) and a telescopic drilling mast (22).

9. The system of claim 8, further comprising a hydraulic engine configured to drive the drill rods (1, 2) of the apparatus (10) into the substrate and out of the substrate.

10. The system of any one of claims 8 or 9, further comprising an injection unit (30) configured as a cart connectable to the mobile drilling platform (20).

11. The system of any preceding claim 8-10, configured to deliver fluid from the injection unit (30) to the fluid supply line (5) provided within the inner drill rod (2) of the apparatus (10).

12. A method for remediation treatment of contaminated subterranean substrate, comprising: a) provision of an injection system comprising the apparatus (10) as defined in any one of claims 1-8, a mobile drilling platform (20) and an injection unit (30), b) establishing a motion of the inner drill rod (2) and/or the outer drill rod (1) into substrate, thereupon a first fluid is conveyed into substrate through the inner drill rod (2) and the injection nozzles (14) provided on the related drill bit (12), c) upon reaching a desired depth, terminating the motion and fluid supply defined at (b), d) establishing supply of a second fluid into substrate through the inner drill rod (2) and the injection nozzles (14) provided on the related drill bit (12), wherein said second fluid is a remediation reagent, and O wherein the movement of each drill rod (1, 2) in the subterranean substrate is N independent on one another.

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13. The method of claim 12, wherein said first fluid is water or air.

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14. The method of any one of claims 12 or 13, wherein said first fluid and/or said second = fluid are conveyed under pressure. © > 35

15. The method of any one of claims 12-14, wherein substrate (43) obtained upon drilling is conveyed upwards through a gap (4) formed between an inner surface of the outer drill rod (1) and an outer surface of the inner drill rod (2) of the apparatus (10) into a collection reservoir (24) provided within the mobile drilling platform (20).

16. The method of any one of claims 12-15, further comprising, in between items (c) and (d), provision of a first sealing arrangement (3) around the outer drill rod (1) on a ground surface (40) and provision of a second sealing arrangement (3A) in the gap (4) formed between the outer- and inner drill rods.

17. Use of the apparatus (10) as defined in any one of claims 1-7 for remediation treatment of contaminated subterranean substrate within a predetermined area, wherein said substrate is an essentially rocky substrate and/or said substrate is laid with pavement. oO

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