AU6081601A - Decontamination plant and procedures - Google Patents

Description

WO 01/83127 PCT/NZO1/00068 DECONTAMINATION PLANT AND PROCEDURES BACKGROUND The present invention relates to a method of decontaminating a site. The present invention is directed to a method of decontaminating a site where a site matrix (topsoil, clay, etc.) has been contaminated with a halo-organic contaminant such as one or more of the DDT isomers, dieldrin, PCBs, etc. The present invention relates to a methodology applicable in a procedure that involves a method of dehalogenation as disclosed in our New Zealand Patent Specification No. 504341 or in the Patent Specification filed simultaneously herewith in the PCT claiming the same priority dates (the details of which are included by reference). The present invention recognises an advantage can be derived by realising just where the contamination largely is in a site and to stream the materials based upon a selection and/or screening procedure such that only part of the material necessarily must be subjected to dehalogenation. A preferred dehalogenation procedure is that which we have developed and which is disclosed in the aforesaid Patent Specification and the Patent Specifications being filed simultaneously herewith. Alternative methodologies for a dehalogenation procedure include that of BIRKE (PCT/DE98/02787) or that of Technological Resources Pty Ltd (AU 9456892) the full content of which are here included by way of reference. STATEMENT OF INVENTION In a first aspect the invention consists in a method of dehalogenating a halo-organic contaminated site which comprises or includes excavating the contaminated site to derive the contaminated media, subjecting the excavated contaminated media to particle size separation to provide at least two streams, namely at least one stream of finer particle sizes ("fine stream(s)") and at least one stream of larger particle sizes ("large stream(s)"), subjecting the fine stream(s) to a dehalogenation procedure, (optionally) subjecting the large stream(s) to a particle reduction procedure, subjecting the fine stream(s) post the dehalogenation procedure and the (optionally particle size reduced) large stream(s) to a blending procedure, and at least one of: (i) site reinstatement with (a) that blend and/or WO 01/83127 PCT/NZO1/00068 -2 (b) other fill, (ii) disposal of that blend. Preferably that blend is used for site reinstatement or disposing of the blend. Preferably there is a single fine stream (eg; s:10 mm) and preferably two large streams (eg; 10 mm - 20 mm and greater than 20 mm). Where (and this is not preferred) the blend is disposed of, other site reinstatement fill may be used. Preferably there is a particle size reduction procedure applied to at least one stream of the larger particle material. Preferably the excavation can isolate clay from topsoil etc. and where clay layers are excavated such clay layers are dried and thereafter are treated as part of the fine stream. Preferably said excavation identifies fine materials for the fine stream by one or both of a) screening and/or b) identification as clay and each is preferably subjected to drying prior to onfeed into the dehalogenation procedure. Preferably clay layers are subjected to solar drying, preferably also along with any fines from a particle size reduction procedure for at least one larger particle stream of said large stream(s). Preferably only the fine layer(s) are subject to the dehalogenation process. Preferably the dehalogenation process is a reactive milling process; ideally in a ball mill. Preferably the milling involves either iron sands or steel makers slag, preferably in the presence of urea, and optionally in the presence of acetic acid. In a further aspect the present invention consists in a blended material produced in a process as aforesaid. In still a further aspect the present invention consists in a material of blended particle streams, the fines stream or streams (unlike the non fines stream or streams) having been subjected to a dehalogenation procedure. Preferably said material is of a kind as results from a methodology as previously stated. In yet a further aspect the present invention consists in a method substantially as herein described with reference to any one or more of the accompanying drawings. In still a further aspect the invention consists in plant or site apparatus substantially as herein described with or without reference to any one or more of the accompanying drawings. This invention may also be said broadly to consist in the parts, elements and features WO 01/83127 PCT/NZO1/00068 -3 referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. Preferred forms of the present invention will now be described with reference to the accompanying drawings in which Figure 1 is a flow diagram showing three streams, one of which is the fine stream (0 to 10 mm particle size) and two of them large particle size streams (say 11 to 20 mm particle stream and a s 20 mm particle stream), the flow diagram showing how the fine stream is subjected to dehalogenation whilst the larger streams are preferably subject to particle size reduction (but not to the fineness of the dehalogenated material post reactor) prior to blending to provide a more stable site reinstatement blend of material than would be the case were the fine stream alone used for site reinstatement post dehalogenation, Figure 2 is a more detailed description of the procedure of Figure 1 showing on site separation of clay materials from top soil materials and how it is that the clay is dealt with in relation to the remainder of the process and additionally showing more detail in a treatment site for positioning at or adjacent a site to be decontaminated, Figure 3 is a plan diagram of a readily created site to treat soils et al adjacent thereto, details of transportable units being given, Figure 4 is a perspective view of a site layout as shown in Figure 3, Figure 5 is a similar view to that of Figure 4 but showing with the added "enclosures" the areas to preferably be subjected to dust control, Figure 6 shows again by "enclosures" those regions preferably to be subject to a measure of noise control (eg; the control office to protect it from ambient noise and the ball mill based reactor to reduce noise dissemination), and Figure 7 is a diagrammatic view of a preferred reactor in accordance with the present invention. The preferred dehalogenation procedure is preferably one that in a mobile ball mill (preferably with balls of less than 30 mm diameter (more preferably about 20 mm diameter)) is energised by its own dedicated prime mover and is adapted to be fed by portable plant the appropriate reactant stream to be milled with the fine stream of preferably 0 to 10 mm topsoil particles plus any dried clay materials that may warrant feeding through the dehalogenation procedure (see Figure 2).

WO 01/83127 PCT/NZO1/00068 -4 In the preferred form of the present invention preferably the dehalogenation involves milling with either iron sands or steel makers slag preferably in the presence of urea and optionally also the presence of an organic acid (such as acetic acid, eg; white vinegar). In the preferred form of the present invention preferably steel makers slag and urea and also (if DDE is involved) white vinegar is used as the reagents. In this respect see our New Zealand Patent Application filed simultaneously herewith the full content of which is hereby here included by way of reference as is also the aforementioned NZ Patent Specification No. 504341. The solid stream is preferably subjected to crushing but there are options here of not crushing the smaller of one or more larger particle streams and/or subjecting one or other of the larger particle streams to washing etc. in case there is a desire to apply any dehalogenation procedure to the slurry to be forthcoming from any such washing. Preferably however washing is unnecessary. Preferably the blending is in any appropriate mixer such as those frequently used for mixing concrete. The apparatus that might be utilised is preferably shown in Figures 3 through 6. Figure 7 preferably discloses a preferred reactor in accordance with the present invention. Preferably however the apparatus shown in Figure 7 is a two chamber KHD Humboldt Wedag AG Palla 65U unit driven by a direct drive (1:1) clutched drive. Whilst an overcentre clutch with a twin disc is preferably used instead the drive could be through a torque convertor. Preferably the empowerment of the drive is with a diesel engine rated from a minimum 400 bhp upwards. We have found most preferably with such a unit that about a 600 bhp GM Detroit Diesel 8V71 is ideal since it provides in conjunction with such a power out (600 bhp) a torque of about 3500 NM. We have found that the KHD Humboldt Wedag AG Palla 65U unit operates well on the 1:1 ratio at 12 rpm at which the GM Detroit Diesel 8V71 is most economical. There is sufficient torque to turn the stationary ball mill over (approximately 3396 nn needed for this purpose) and sufficient torque in excess of that figure to meet the maximum torque requirement of the mill which occurs at approximately 150 rpm after which it drops back thus enabling the engine to operate at 1200 rpm (the engine has maximum torque at 1500 rpm). With respect to Figures 3 through 6 we now describe the plant by reference to the reference numerals. Description/Containers/Primary Function: 0 Rotary Trommel - Product Sizing WO 01/83127 PCT/NZO1/00068 - 1 qty 20ft ISO @ Rotary Drier - Product Drying - 1 qty 40ft ISO @ Blending Plant - Mixing of product with reagents - 1 qty 40ft ISO - 2 qty 20ft ISO 0 Reactor - - Processing - 1 qty 40ft ISO 0 Product Out-feed Discharge System with wet dosing/ammonia removal. - 1 qty 40ft ISO @ Control Office - Process management - 1 qty unit, loose Associated Augers - N/A - 6 qty General Description of each Section, Function and Approximate Weight: 0 Rotary Trommel: The rotary trommel accepts product <20mm, and discharges product >10mm to a washing plant, with the <10mm product being transferred by auger/conveyor (to be determined) to the rotary drier. The supply of product to the rotary trommel (to be done by others - the product rate is to be advised in both tonnage, cubic metres and specific gravity). It is assumed that the >20mm/m may be washed and the sediment will be subject of a solar treatment process to be operated on site, the materials handling and subsequent feeding to the blending plant to be determined. Oversize product is moved to the post process blender to restore our GEOTECHTM standards to sub micro processed product. Energy Requirements:.................................... Approximately 15kW Anticipated Noise Level:................................ 70dba WO 01/83127 PCT/NZO1/00068 -6 Production Capacity:...................................... 5 tonnes/hour of <10mm product D im ensions:.................................................... 20ft ISO Anticipated W eight:....................................... 6000kg (gross) @ Rotary Drier: The rotary drier accepts from an auger feed, through the centre of the rotary drier, <10mm product with moisture contents varying from 30% to 5%. The requirement will be to produce product dried to <2%, with the drying chamber not to exceed 70'C. It is envisaged that both continuous and batch operations can be operated, depending on moisture content, and production flow at the main plant. Principle of operation, is central loading with a recirculating airflow system, with the heat provided by diesel fired burner nozzles, similar to those used in bitumen plants. The drier rotation speed approximately 10rpm, with the discharge occurring via a external circular dome of mesh, of approximately <10mm, (can be varied depending upon project and process size). Throughput rate is difficult to determine because of the unknown moisture content. Discharge either continuous or batch is achieved via hydraulic actuated cylinders altering the angle of the rotating drum frame. Air discharge is connected to the bag house in the reactor cell, with twin drop boxes in the ducting. It would be preferable that the drier be operated on a timer depending on requirements so that daily product is dried for the next day's production. Energy Requirements:......................... Fanl5kW, Drive Drum 15kW Anticipated Noise Level:.................... 65dba Production Capacity:........................... 5 tonnes/hour of <10mm product Dimensions:......................................... Drum 8m long, 2.5m wide, mounted on 40ft ISO Anticipated W eight:............................. 11,000kg @ Blending Plant Three load hoppers are sited at ground level, low enough for front-end loader to feed product. Product is screw fed from the bottom of each hopper and fed to an elevator to deliver it into various bulk hopper containers. The bulk hopper is a "mass flow design" and is complete with a vibratory feeder mounted to the base. High and low sensors are fitted to the bulk hopper with a visual warning for the operator to fill the hopper. From the outlet of the hopper, an actuated valve is used to control the product dump into WO 01/83127 PCT/NZO1/00068 -7 a loss and weight feeder. This fills the feeder to present limits. The loss and weight feeder is complete with an accurate weight system, which continuously monitors the flow rate from the feeder and automatically adjusts as required. The product enters a continuous mixer, and once thoroughly mixed with the appropriate reagents is transferred to the reactor at a controlled rate, via vertical auger. The product can be fed at variable production speeds from 2 tonnes/hour to 12 tonnes/hour. The relationship of main product to reagents can be varied from 2% to 12%. Reagent silos are designed to accommodate approximately one week's production so they can be bulk loaded. The main product silo is designed to handle a minimum of 1.5 days production. The stop/start of the entire plant and blending ratios is controlled via a PLC in the control room. The mixing auger is a loose item as is the vertical screw conveyor. Energy Requirements:............... Full operational, 50kW via 14 various kW electric drives Anticipated Noise Level:............................ 75dba Production Capacity:.................................. Fed at variable speeds from 2 tonnes/hour to 12 tonnes/hour Dimensions:............................................... 1 qty 40ft ISO on site, tipped vertically with leg stands, carries main product silo 2 qty 20ft ISO, with each carrying a reagent and the associated auger equipment Anticipated Weight:................................... Approximately 15,000kg (gross) 0 Reactor: The Reactor preferably as shown in Figure 7 accepts dried product of <2% moisture content, which has been blended to the required percentages with the appropriate reagents, depending on contamination levels. The product enters the upper chamber nd proceeds along the upper chamber, via natural displacement, discharging to the lower chamber in a series configuration, via a pre-set retention-timing valve. Product continues along the outer chamber, and discharges, to the product out-feed screw conveyor to the wet dosing plant. The reactor is driven once by a rotating diesel engine producing about 475bhp. The entire plant is encased in an acoustic airtight container, with an in-built bag house and air emission extractor fan system. Energy Requirements:..................................... Air extraction fan 11.5kW, engine requires 60 litres/hour. Anticipated Noise Level:................................ 95dba full operational WO 01/83127 PCT/NZO1/00068 Production Capacity:....................................... Production rates depending on contamination levels can vary from 5 tonnes/hour to 20 tonnes/hour Dim ensions:.................................................... 1 qty 40ft ISO container Anticipated W eight:........................................ 5000kg loaded As can be seen preferably the rotary trommel 1 (is a 20ft ISO) transportable unit, the rotary drier 2 a 40ft ISO transportable unit, the reactor 4 a 40ft ISO transportable unit, the blending plant 3 a readily transportable unit, the outfeed discharger a 40ft ISO unit, the bins by their very nature readily transportable, eg; 30m 2 bins, and the control office itself preferably being a readily transportable building structure. In Figure 7 there is shown a heavy chassis 7 from which static pedestals 8 project. It is on these pedestals 8 that flexible pads 9 are positioned which in turn support the ball mill 29 by virtue of it lateral extensions 10 thereof. This confinement between banks of pedestals 8 of the preferred ball mill (for example, a KHD Humboldt Wedag AG Palla 65U twin chamber ball mill) is such as to minimise the vibrating mass to be stabilised by the "static" counterweight mass of the engine, etc. and the chassis, pedestals, etc. There is an infeed 11 into a preferred first and upper chamber 12 of the ball mill and from thence a feed via 13 down into the second chamber 14 having an outlet 15. The direct drive at 16 to the eccentric(s) [not shown] is via a clutch 17 (preferably an overcentre twin disc clutch) from the engine 18. As previously stated the engine preferably is a GM Detroit Diesel 8V71 capable of producing approximately 600 bhp and a torque output of 3500NM. Preferably the mill operates at 1200RPM of shaft 16 and thus the engine after having overcome the peak torque requirement on shaft 16 of about 3396NM at 150RPM. Preferably a braking mechanism 19 is also provided such that the rotation of the drive 16 can be halted to damp excessive fibrations during wind down. The unit preferably to a 40ft ISO transportable unit size preferably includes an extractor fan 19 and filters 20. @ Product Out-feed Discharge System with Wet Dosing/Ammonia Removal and Geotech Blender: WO 01/83127 PCT/NZO1/00068 -9 Product enters into the side of the 40ft ISO container approximately 2m - 3m from the end. A belt conveyor introduces it. Once in the container, the product is spent evenly over a 2.2m width continuous belt conveyor to form a blanket of 10mm thick, to fall within the width of the belt. During the belt conveying distance of 7.7m running along the base of the container, water spray is introduced overhead to saturate the conveyed product. The volume of water will depend on the conveyor speed, in turn depending on the reactor output. Crushed aggregate is mixed during this process to restore GeotechTM qualities. The product exits the container after arriving approximately 1.5m at the end of the conveyor for a pile to form. Product being discharged can be discharged into 25/30m 3 rear container hook type bins, where the bins can be analytically sampled prior to being uplifted by articulated dump truck and returned to the excavated site. A simple baffle type wet scrubber installed in the rear of the container achieves the emissions of odours from this process. This extracted air passes through a saw-tooth baffle, which creates a whitewash scrubber action, similar to a Venturi scrubber. There is no water pump required to achieve this progress. The extraction fan with its high volume capabilities will extract the water through the baffles alone. The extracted air, which is entering the scrubber, has originated from the opposite end of the container. A baffle forms an air gap between the exit point of the conveyor and the baffle. This provides an extraction rate of 6.6m/sec through the slot. This will maintain the dry airborne dust within the prolonging saturated period. A slow cross draught down the length of the container will exist at approximately 0.3m/sec. This will carry a small percentage of sub-micron particles, along with water vapour within the container. There will be emissions from the scrubber of the smaller deposits. The fan would exhaust vertically at a rate of 18m/sec to assist in the dilution of odour emissions. The complete system with the exception of the conveyor between the reactor and the scrubber container will be housed inside a 40ft ISO. All manufactured panels, fans, and scrubbers are of stainless steel. Energy Requirements:.................................... 31kW - being 11kW for the extraction fan, and 20kW for conveyor drives Anticipated Noise Level:................................ 60dba Production Capacity:....................................... 5 to 10 tonnes/hour Dim ensions:.................................................... 40ft ISO container Anticipated W eight:........................................ 5,000kg @ ControlOffie: WO 01/83127 PCT/NZO1/00068 -10 The entire plant can be operated from a remote control office connected by umbilical cords. This means that the starting of the rotary trommel for the particle separation, the rotary drier, all blending plant and ratios, and the stop/start of the reactor and the out feed product conveyors are all separate stop/start switches. The control office will be air conditioned, and will be video linked to all of the associated modules. Total Anticipated Plant Weight:................................ 90 tonnes. Total Plant Electrical Requirement on Site Fully Operational:.................... 100kW (approx) Total Number of Containers and Ancillary:............. - 4 qty 40ft ISO - 3 qty 20ft ISO - Site Office - Loose feeder - Conveyors - Augers Dehalogenation Procedures As discussed in here the preferred dehalogenation procedures are preferably milling procedures preferably using a milling procedure which has a higher energy than a rod mill procedure. As used herein however the term "ball" milling includes within its ambit alternatives to a strict ball form which nonetheless has an energy approaching that of ball milling. Whilst the preferred dehalogenation procedure will hereafter be described other procedures are capable of being used including: - catalytic reductive dehalogenation - reductive dehalogenation - solvent extracting - biological dehalogenation - reactive milling. Other such procedures for dehalogenation are also possible for use with the invention, as are known within the art. In respect of the reactive milling procedure which is preferred we now describe our preferences.

WO 01/83127 PCT/NZO1/00068 - 11 They may employ "iron sands", and/or "steel makers slag". Reference herein to "iron sand" includes any appropriate iron sand for the procedure. All such iron sands are preferably titanoferromagnetite sands. One such sand is that of, for example, BIP New Zealand Steel Limited having a content substantially as set out in Table 1 (being an analytical report of two samples). Reference hereto to "steel makers slag" includes any suitable slag with iron or titanium values but preferably is a slag with both iron and titanium values such as that of BHP New Zealand Steel Limited. The slag such as that set out in Table 2 is preferably post-crushing, and magnestic extraction of any zero oxidation state values initially present prior to oxidation thereof. Table 2 is an example of BHP New Zealand Steel Gap 10 slag. TABLE 1: Iron Sands ANALYTICAL REPORT SAMPLE SAMPLE FCA 5480 FCB 5481 Total Fe 59.1 59.1 values % CaO % 0.40 0.38 SiO 2 % 2.52 2.42 TiO 2 % 8.07 8.02 A1 2 0 3 % 3.87 3.88 MgO % 2.93 2.82 P % 0.034 0.032 V20 3 % 0.47 0.52 MnO % 0.64 0.64 S % 0.007 0.006

NA

2 0 % <0.100 <0.100 K20 % 0.050 0.051 Cu % <0.007 <0.007 Cr % 0.035 0.032 Zn % 0.068 0.068 The Fe values are present in other than the zero oxidation state.

WO 01/83127 PCT/NZO1/00068 -12 TABLE 2: Steel Makers Slag Si0 2 11.32% w/w TiO 2 31.34% MgO 12.76% CaO 15.98% Total Fe values 8.45% A1 2 0 3 16.88% MnO 0.88%

V

2 0 3 6:50 S 0.18% The Fe values are present as oxides or other than zero oxidation state values. Examples Example 1: Soil (7 kg) contaminated with DDT (390 mg/kg dry weight) and dieldrin (71.4 mg/kg dry weight) was mixed with acetic acid (250 g, 99.7% purity), water (380 g) and iron sand (1.40 kg). The 7 kg soil sample was undried and had a moisture content of 9.3% prior to the addition of any reagents or additional water. This mixture was then placed in a vibratory ball mill and milled for 30 minutes. The mill was then discharged, and urea (1.05 kg) and iron sand (700 g) were mixed into the soil. The mill was reloaded, and the mixture milled for a further 30 minutes. The mill temperature was above 70 0 C for the entire procedure. GC-ECD analysis showed a 99% reduction in DDT levels, and a 99.7% reduction in dieldrin levels. No other halo-organic substances were detected. Example 2: Soil (7 kg) contaminated with DDT (390 mg/kg dry weight) and dieldrin (71.4 mg/kg dry weight) was mixed with vinegar (630 g) and cast iron filings (1.40 kg). The soil was undried and had a moisture content of 9.3% prior to the addition of vinegar. This mixture was placed in a vibratory ball mill and milled for 30 minutes. The mill was then discharged, and urea (1.05 kg) and iron sand (700 g) were mixed into the soil. The mill was reloaded, and the mixture was ground for a further 30 minutes. The mill was discharged again, an additional batch of urea (1.05 h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 - 13 kg) and cast iron (700 g) was mixed into the soil, and the mixture was milled for a further 30 minutes. The mill temperature was above 90 C for the entire process. GC-ECD analysis showed a 98.4% reduction in DDT levels, and a 99.7% reduction in dieldrin levels. No other halo-organic substances were detected. Example 3: Soil (7 kg) contaminated with DDT (390 mg/kg dry weight) and dieldrin (71.4 mg/kg dry weight) was mixed with vinegar (630 g) and cast iron filings (1.40 kg). The soil was undried and had a moisture content of 9.3% prior to the addition of vinegar. This mixture was placed in a vibratory ball mill and milled for 20 minutes. The mill was then discharged, and urea (700 g) and iron sand (700 g) were mixed into the soil. The mill was reloaded, and the mixture was ground for a further 20 minutes. The mill was discharged again, an additional batch of urea (700 g) and cast iron (700 g) was mixed into the soil, and the mixture was milled for a further 20 minutes. The mill temperature was above 85 C for the entire process. GC-ECD analysis showed a 97.9% reduction in DDT levels, and a 99.0% reduction in dieldrin levels. No other halo-organic substances were detected. Example 4: Soil (7 kg) contaminated with DDT (390 mg/kg dry weight) and dieldrin (71.4 mg/kg dry weight) was mixed with iron sand (1.40 kg), calcium sulphate (700g) and urea (700g). The soil was undried and had a moisture content of 9.3%. This mixture was placed in a vibratory ball mill and milled for 30 minutes. The mill was then discharged, and urea (350 g) and iron sand (350 g) were mixed into the soil. The mill was reloaded, and the mixture was ground for 15 minutes. The mill was then discharged again, and an additional batch of urea (350 g) and iron sand (350 g) was mixed into the soil. This mixture was milled for 15 minutes. The mill temperature was above 70'C for the entire process. GC-ECD analysis showed a 96.9% reduction in DDT levels, and a 98% reduction in dieldrin levels. No other halo-organic substances were detected. Example 5: Soil (7 kg) contaminated with DDT (390 mg/kg dry weight) and dieldrin (71.4 mg/kg dry weight) was mixed with iron sand (1.40 kg) and urea (700g). The soil was oven-dried at 60"C h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -14 prior to use. This mixture was fed through an open vibratory ball mill. The residence time in the mill was 6 minutes. Additional urea (350 g) and iron sand (700 g) was mixed into the soil, and the mixture was fed through an open mill. The mill took 9 minutes to discharge. A final batch of urea (350 g) and iron sand (700 g) was mixed into the soil, and the soil was once again fed through an open vibratory bore mill. The time taken for total mill discharge was 14 minutes. This mixture was milled for 15 minutes. The mill temperature was above 70'C for the entire process. GC-ECD analysis showed a 95.1% reduction in DDT levels, and a 90.9% reduction in dieldrin levels. No other halo-organic substances were detected. Example 6: Soil (6.62 kg, oven-dried and pre-milled) contaminated with DDT (720 mg/kg dry weight) and dieldrin (64 mg/kg dry weight) was mixed with iron sand (1.24 kg) and urea (1.24 kg). This mixture was placed in a vibratory ball mill and milled for 30 minutes. The top of the mill was then opened, and urea (662 g) was poured in on top of the soil. The mixture was then milled for a further 30 minutes. GC-ECD analysis showed a >99% reduction in DDT levels, and a >97% reduction in dieldrin levels. No other halo-organic substances were detected. Example 7A and 7B: Soil (3.2 kg, oven-dried) contaminated with DDT (868 mg/kg) and dieldrin (64 mg/kg) was mixed with magnesium filings (160 g) and milled for 10 minutes. Butylamine (160 g) was then added and the mixture was milled for a further 10 minutes. GC-ECD analysis showed this trial (Example 7A) a 65.7% reduction in DDT levels, and a 46.9% reduction in dieldrin levels. It should be noted that DDT isomers were replaced by DDE, i.e. a significant increase in DDE isomers was observed. It appears that this process as disclosed in PCT/DE98/02787 is not effective for treating DDE isomers. This trial has a shorter time in the mill and lower reagent percentages than the more successful. A repeat (Example 7B) with the same conditions save using urea instead of butylamine resulted in 93.5% DDT reduction and 68.8% dieldrin reduction. Example 8 To test mechanical/chemical effects on changing ball diameter from 30mm to 20mm in a h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 - 15 steel ball mill. Sample: 0 15kg uncontaminated soil dried. O Spiked with 150g DDT concentrate 20%, and 150g dieldrin concentrate 4% (both liquid), hand mixed, then mixed for 30 minutes in concrete mixer. O Sample A taken. Milled with 30mm halls: @ Mill warmed and cleaned with 7kg DDT/Dieldrin spiked soil (as in Sample A) and 10% urea. @ Spiked with 5% urea and 5% iron sand @ Mill run for 20 minutes and then discharged for 15 minutes. @ Sample B taken. Milled with 20mm balls: @ Mill warmed and cleaned with 7kg DDT/Dieldrin spiked soil (as in Sample A) and 10% urea. @ Spiked with 5% urea and 5% iron sand. @ Mill run for 20 minutes and then discharged for 15 minutes. @ Sample C taken. TABLE 3 - Example 8 Results: Sample DDT (ppm) Dieldrin (ppm) A (not milled) 4490 750 B 30mm balls 2320 335 C 20mm balls 138 18 Example 9 Rod Milling Verses Ball Milling: Contaminated Mapua soil (7kg), iron sand (10%) and urea (5%) were mixed and milled for 10 minutes (sample (I)). h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -16 An additional 5% urea was mixed in, and the mixture milled with ferrous rods (not balls) for an additional 10 minutes (sample (II)). The rods were replaced with ferrous balls of substantially similar mass, and another 5% of urea was added to sample (II), and it was milled for a further 20 minutes. Sample (III) was taken at the beginning of the discharge, sample (IV) was taken at the end of the discharge. At a later date, a further 5% of urea was added to sample (IV), and it was milled for a further 30 minutes (sample (V)). At a still later date, a further 5% portion of urea was added to sample (V), and it was milled for a further 60 minutes (sample (VI)). All milling were as a similar energy input. TABLE 4 - Example 9 Results: I II Ill IV V VI (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) Dieldrin 73.3 71.0 5.3 0.6 1.3 0.8 2,4'-DDE 2.5 2.2 1.5 0.7 0.5 0.5 2,4'-DDD 9.1 7.7 4.6 0.9 0.8 0.6 2,4'-DDT 67.6 73.0 <0.1 <0.4 0.8 0.3 4,4'-DDE 19.7 15.5 12.6 5.8 3.0 2.0 4,4'-DDD 38.3 29.2 2.5 0.2 0.8 0.4 4,4'-DDT 257 324 <0.1 <0.1 2.2 0.4 Total DDT 394 452 21.1 7.6 8.1 4.1 isomers Dehalogenation does not occur as effectively when balls inside the mill were substituted with rods. Example 10 Sydney clay (6.13 kg), iron sand (613g, 10%) and urea (307g, 5%) were mixed well and milled for 10 minutes (sample (i)). Another 5% of urea was mixed in, and the mixture milled for a further 10 minutes (sample (ii)). NB: the mill was filled with ferrous rods, not ferrous balls for samples (i) and (ii). The rods were replaced with ferrous balls, and the mixture was milled for a further 20 h:\1ibrary\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -17 minutes (sample (iii)). 5% iron sand and 5% urea (307 g of each) was then mixed in, and the mixture milled for 10 minutes (sample (iv)). Acetic acid (200 g) was then added, and the mixture milled for 10 minutes (sample (v)). Another 5% urea was added to the soil, and this mixture was milled for a further 20 minutes (sample (vi)). TABLE 5 - Example 10 Results Original (i) (ii) (iii) (iv) (v) (vi) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) Dieldrin 4.0 9.6 10.9 14.0 14.1 2.2 1.5 2,4'-DDE 0.3 2.0 2.0 2.2 2.0 1.9 1.0 2,4'-DDD 7.0 5.4 4.6 6.3 5.2 2.4 1.6 2,4'-DDT 9.8 8.3 10.3 5.5 1.8 <0.1 <0.1 4,4'-DDE 2.1 5.0 6.4 9.6 13.9 10.9 5.6 4,4'-DDD 20.9 17.8 14.0 25.5 15.1 2.6 1.4 4,4'-DDT 47.1 32.4 40.7 22.2 6.4 <0.1 <0.1 Total DDT 87.1 71 78 71.3 44.4 17.8 9.6 isomers Clearly ball milling is a preference over rods even for contaminated clays. Example 11 Sydney clay (3 kg) (as used in Example 10) had iron sand (10%) and acetic acid (3%) added to it. The mixture was run through ball mill, and samples were taken after 40 min (Sample (A)). At a later date, another 10% urea was added to the mixture, and it was milled 2 x 30 minutes (sample (B)). TABLE 6 - Example 11 Results Sample (A) (B) (mg/kg dry weight) (mg/kg dry weight) Dieldrin 2.2 0.6 h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 - 18 Sample (A) (B) (mg/kg dry weight) (mg/kg dry weight) 2,4'-DDE 1.5 0.8 2,4'-DDD 1.6 0.1 2,4'-DDT 0.2 <0.1 4,4'-DDE 9.5 6.2 4,4'-DDD 1.8 <0.1 4,4'-DDT 0.3 0.1 Total DDT 14.9 7.4 isomers Example 12 Mapua soil with a mean contamination content in a less than 5 mm screened fraction of 71.9 mg/kg of dry weight Dieldrin and of 412 mg/kg of dry weight total of DDT isomers was then subjected to a milling procedure. Soil Preparation Contaminated soil as excavated was spread out on a tarpaulin and mixed well. Soil was then sieved through a 5mm sieve. The < 5mm fraction was collected and dried overnight in an oven kept at 50'C prior to use in the milling trials. The > 5mm fraction was used in soil washing trials. Approximately 43% of stockpile was < 5mm, and approximately 57% was > 5mm. Initial Concentrations of DDT and dieldrin in <5mm Soil Fraction: Portions of the <5mm fraction were oven-dried at 50'C overnight, ground in the mill and analysed for DDT and dieldrin. Results are presented in Table 7. TABLE 7 - Initial DDT (which may included the related DDE, DDD) and Dieldrin Concentrations h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -19 RunA Run B Run C (mg/kg dry weight) (mg/kg dry weight) (mg/kg dry weight) Dieldrin 71.4 73.3 71.0 2,4'-DDE 0.5 2.5 2.2 2,4'-DDD 7.8 9.1 7.7 2,4'-DDT 77.3 67.6 73.0 4,4'-DDE 3.7 19.7 15.5 4,4'-DDD 14.6 38.3 29.2 4,4'-DDT 286 257 324 Total DDT isomers 390 394 452 Mechanochemical Dehalogenation Process (MCD) Trial carried out in triplicate Procedure: Soil (4kg of the oven-dried <5mm fraction) was mixed with iron sand (200g, 5%) and acetic acid (2%). This mixture was introduced into the ball mill and milled for 30 minutes. The mill was the discharged, and a soil sample (150g) was taken. The milled soil was then mixed well with urea (400g, 10%) and iron sand (200g, 5%). This mixture was milled for a further 30 minutes. The mill was then discharged, and the soil was re-introduced into the mill (no extra reagent addition), and milled for another 30 minutes. A sample (150g) was taken for analysis. The above trial was carried out in triplicate (Runs A, B and C). Results are shown in Table 8. TABLE 8 - Results from Trial Carried Out in Triplicate (Runs A, B & C): RunA Run B Run C (mg/kg dry weight) (mg/kg dry weight) (mg/kg dry weight) Dieldrin 0.73 0.3 0.5 2,4'-DDE 0.22 0.4 0.5 2,4'-DDD 0.37 0.1 0.3 2,4'-DDT 0.02 <0.1 <0.1 4,4'-DDE 2.54 4.5 4.4 4,4'-DDD 0.41 0.2 0.4 4,4'-DDT 0.02 <0.1 <0.1 Total DDT isomers 3.57 5.3 5.6 TABLE 9 - Statistical Analysis of Treated Soil (Triplicate Trials) h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -20 Mean Treated UCL (95%) LCL (95%) % Soil (mg/kg dry Treated Soil Treated Soil Reduction weight) (mg/kg dry (mglkg dry weight) weight Dieldrin 0.5 0.7 0.3 99.3% Total DDT isomers 4.8 5.9 3.7 98.8% From these results it can be seen that an initial concentration of 71.9 (+/- 2.2) ppm dieldrin in our source has been reduced to 0.5 (+/- 0.2) ppm. Likewise, an initial concentration 412 (+/ 35) ppm DDT in our source has been reduced to (4.8 +/- 1.1) ppm. It should be noted that these results are for the highly contaminated < 5mm fraction. Recombination of this soils with the washed > 5mm fraction will further decrease both DDT and dieldrin concentrations. Soil Washing Trial Two runs with the same soil source were carried out in order the determine the effectiveness of washing the > 5mm fraction from our source. Soil was washed in a cement mixer that had 5mm holes around the edge. Results are presented in Table 10. TABLE 10 - Results from Soil Washing Trials of Larger than 5 mm Fraction. Run1 Run2 (mg/kg dry weight) (mg/kg dry weight) Dieldrin 0.2 0.3 2,4'-DDE <0.1 <0.1 2,4'-DDD 0.2 <0.1 2,4'-DDT 0.2 0.1 4,4'-DDE <0.1 <0.1 4,4'-DDD 0.6 0.4 4,4'-DDT 0.3 0.2 Total DDT isomers 1.3 <0.8 Application of The Process Range of Contaminants and Waste Material Expected. Our pilot plant trials conclude that initial pesticide reductions, using the process of h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -21 concentrations where the variations of DDT from 850 mg/kg to 320 mg/kg has little impact in the first stage of the process. This means the process has little problem in quickly achieving reductions of DDT down to 50 mg/kg. In respect of dieldrin, the same can be said, where initial concentrations have varied from 80 mg/kg to 70 mg/kg. First stage results generally are down to the region of 10 mg/kg. Example 13: We have tested the MCD Process on clay from a different site, and found that it works effectively on clay as well as on soil. We expect the MCD Process to dehalogenate all halogenated contaminants present. This includes PCBs. Substances such as heavy metals or sulphur should not affect the MCD Process, however, it should be noted that the MCD Process does not eliminate heavy metals, and if these are present above acceptable levels, those portions of soil may have to be landfilled. Example 14: Trial: To test process with each of SR3-BHP New Zealand Slag and Gap 10 slag of BHP New Zealand Steel Limited. - The general chemical composition of SR3-BHP New Zealand Slag is more akin to "pig iron" - The general chemical composition of the BHP New Zealand Gap 10 slag is as follows: - SiO 2 - 11.32% - TiO2 -31.34% - MgO - 12.76% - CaO - 15.98% - Total Fe values - 8.45% - A1 2 0 3 - 16.88% - V 2 0 3 - 0.28% - MnO - 0.88% - S-0.18% - 15kg of dried sand slag (screened to particle size less than 7 mm) was mixed with 100g DDT (12.5% concentrate) pellets and 75g dieldrin (4% concentrate) liquid. - The product was mixed for 10 minutes in the mixer. - The Control Sample was extracted. h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -22 Run 1: - 5kg of material identical to the control sample was extracted from the mixer, - The material was mixed with 10% of the SR3 slag, 5% of unfiltered white vinegar (10% concentrate) and 5% urea. - The mill was operated for 20 minutes. - The Run 1 sample was extracted. Run 2: - 5kg of the material identical to the control sample was extracted from the mixer. - The material was mixed with 10% unscreened slag sand, 5% unfiltered white vinegar (10% concentrate) and 5% urea. - The mill was operated for 20 minutes. - The Run 2 sample was extracted. Run 3: - 5kg of material identical to the control sample was extracted from the mixer. - The material was mixed with 10% of Gap 10 slag (ie, screened to particle size less than 10 mm), unfiltered white vinegar (10% concentrate) and 5% urea. - The mill was operated for 20 minutes. - Run 3 sample was extracted. TABLE 11 - Results: Sample DDT % Reduction Dieldrin % Reduction Control (Not Run) 1430 - 328 Run 1 (SR3) 580 59.4% 177 46% Run 2 (Slag sand) 202 86% 110 66% Run 3 (Gap 10 slag) 33 97.6% 6.1 98.1% Example 15: Trial: To test the Process in Respect to PCBs. - 5kg of dried Gap 7 BHP New Zealand slag (screened to particle size less than 7mm) to simulate soil was mixed with 32 grams of liquid PCB. h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 - 23 - Control Sample extracted. - Material identical to the Control Sample was mixed with 10% by weight of the Gap 10 sand (ie slag screened to particle size less than 10 mm), 5% of dry untreated vinegar (10% concentrate) and 5% urea. - Run 1 sample extracted. TABLE 12 - Results: (ppm) Sample PCB % Reduction Control (Not Run) 2750 Run I (Gap 10 slag) 660 76% Example 16: Trial: To Check DDT/Dieldrin Reaction with Lower Ratios of Some Reagents - 5kg of the same dried slag sand (screened to particle size less than 7 mm) to simulate slag was mixed with 33g of DDT and 26g dieldrin (similar ratios as Example 14). - Control sample extracted. - Material with content as in the control was mixed with 10% by weight of GAP 10 slag but 2.5% white vinegar (10% concentrate) and 2.5% urea. - The mill was run for 20 minutes. - Run 1 sample extracted. TABLE 13 - Results: Sample DDT % Reduction Dieldrin % Reduction Control (Not Run) 1430 - 328 Run 1 30 98% 10 97% Example 17: A Full Scale Trial: - 2 cubic metres of aggregate (screened to particle size less than 7mm), solar dried and having a specific gravity of 1558 kg/m 3 was mixed with 10% by weight BHiP New Zealand steelmakers slag (screened to less than 10mm and having had any iron present removed magnetically) and 10% by weight urea. - The material spiked with 4 kg of 50% concentrate DDT in powder form and thoroughly h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 - 24- - ;Ut mixed. - It was then further mixed with 7.5 kg of 4% concentrate dieldrin pellets. - Mixing was done using a mini-excavator for a period of three hours. - The mixed product was sampled to provide the spiked sample. - Product was then loaded into the reactor and the discharge was collected. TABLE 14 - Results: Untreated Calculation of Post Process % Reductions Spiked Sample Samples Achieved (mg/kg dry weight) 2 Dieldrin 96.3 ppm <0.5 ppm >99.5% Total DDT 642 ppm <3 ppm >99.5% isomers Proposed Methodology in Practice See enclosed Figures 1 to 5 hereof and our patent applications filed simultaneously herewith. Excavation of Contaminated Material Material will be excavated from agreed contamination zones, to designated depths by a tracked excavator, having a wide bucket, with a sharp cutting edge. Visual Product Selection (i) Majority of Excavated Product (Excluding Clay Seams) Post excavation transport, product is fed on to a primary screen where the oversize rock (> 100mm) will be stockpiled. Subject to further analysis (this has not been done because the representative sample was screened to <50mm), if contamination levels require remediation, this sized product can be either washed, or crushed and run through the dehalogenation plant. If this product meets a satisfactory standard, subject to client specifications, it can be crushed and used as fill or placed as base course. The process diagram incorporates a washing system, and if needed a simple trommel is used. Product screened to < 50mm will is placed in a dry trommel, and screened to < 5mm, prior to loading into the MCD Plant. Product > 5mm is washed in a wet trommel, where the extracted sediment is rotary dried and joins the < 5mm particle sizing. The> 5mm washed product, is crushed to client preference, sizing and also replaced on site as base fill and/or be part of the end product homogenized mix. h:\library\patents\djj\specs\440937.wpd WO 01/83127 PCT/NZO1/00068 -25 (ii) Clay Identifying specific clay seams, during excavation is important. Physical clay seam separation during excavation for separate drying reduces processing costs. Pre-drying would be of a passive type, in a dedicated fully enclosed shed, constructed on site, similar to a commercial vegetable growers hothouse. An air extraction/dust collection system will be installed. (iii) Quantities of Additives Additives, used in the pilot plant, which might be introduced in a full scale plant are - Additive A - Iron Sand or Steel makers Slag (10% - by product dry weight) - Additive B - Acetic Acid (2% - by product dry weight) [eg; as white vinegar]. - Additive C - Urea (10% - by product dry weight)

Claims (24)

1. A method of dehalogenating a halo-organic contaminated site which comprises or 5 includes: - excavating the contaminated site to derive the contaminated media, - subjecting the excavated contaminated media to particle size separation to provide at least two streams, namely at least one stream of finer particle sizes ("fine stream(s)") and at least one stream of larger particle sizes ("large stream(s)"), 10 - subjecting the fine stream(s) to a dehalogenation procedure, - subjecting the fine stream(s) post the dehalogenation procedure and the large stream(s) to a blending procedure, and -at least one of: -(i) site reinstatement with 15 (a) that blend, and/or (b) other fill, -(ii) disposal of that blend.

2. A method as claimed in claim 1 wherein the site is reinstated at least with that blend. 20

3. A method as claimed in claims 1 or 2 wherein there is a single fine stream and two large streams.

4. A method as claimed in any one of the preceding claims wherein said fine stream has an 25 average particle size of substantially 10mm or less.

5. A method as claimed in claim 4 wherein the fine stream has an average particle size smaller than or equal to substantially 10 mm, and a first large stream having an average particle size substantially in the range 10 mm - 20 mm, and a second large stream having an average 30 particle size greater than or equal to substantially 20 mm.

6. A method as claimed in in any one of the preceding claims wherein the large stream (when there is a single large stream) or at least one of the large streams (when there is more than -27- PCT/NZQI 00 0 6 0 one large stream) is subjected to a particle reduction procedure prior to the blending procedure.

7. A method as claimed in claim 6 wherein the excavation isolates clay from topsoil etc. and, 5 where clay layers are excavated, such clay layers are dried and thereafter are treated as part of the fine stream.

8. A method as claimed in any one of the preceding claims wherein the excavation identifies fine materials for the fine stream by one or both of 10 a) screening and/or b) identification as clay.

9. A method as claimed in claim 8 wherein a) and or b) is subjected to drying prior to onfeed into the dehalogenation procedure. 15

10. A method as claimed in claims 9 wherein where clay layers exist they are subjected to solar drying.

11. A method as claimed in claim10 wherein the clay layers are subjected to solar drying along 20 with any fines from a particle size reduction procedure for at least one larger particle stream of said large stream(s).

12. A method as claimed in any one of the preceding claims wherein only the fine stream(s) are subject to the dehalogenation process. 25

13. A method as claimed in any one of the preceding claims wherein the dehalogenation is via one of more of the following processes: - catalytic reductive dehalogenation - reductive dehalogenation 30 - solvent extracting - biological dehalogenation - reactive milling. PCT/NZ01/ 0 0 6 8 -28

14. A method as claimed in any one of the preceding claims wherein the dehalogenation is a reactive milling process.

15. A method as claimed in claim 14 wherein the milling process takes place in a ball mill. 5

16. A method as claimed in claim 15 wherein the milling process involves milling with either: a) iron sands, or b) steel makers slag. 10

17. A method as claimed in claims 16 wherein the milling is in the presence or urea.

18. A method as claimed in claim 17 wherein the milling is further in the presence of acetic acid. 15

19. A method as claimed in any one of the preceding claims wherein when the blend is disposed of, any other site reinstatement fill is used.

20. A blended material produced in a process as aforesaid. 20

21. A material of blended particle streams, the fines stream or streams (unlike the non-fines stream or streams) having been subjected to a dehalogenation procedure.

22. A material as claimed in claim 21 wherein the material is of a kind as results from a methodology as previously described. 25

23. A method substantially as herein described with reference to any one or more of the accompanying drawings.

24. Plant or site apparatus substantially as herein described with or without reference to any 30 one or more of the accompanying drawings.