WO1995001230A1 - Method and device for sediment detoxification - Google Patents

Abstract

A method and apparatus for the treatment of sediment. The apparatus (30) provides a plurality of injection sites (38, 58) for injecting a biochemical oxidant into the sediment. The oxidant is useful for oxidizing a bacterial growth inhibitor to a non-inhibiting form thus permitting bacterial growth and thus greater numbers for sediment detoxification.

Description

METHOD AND DEVICE FOR SEDIMENT DETOXIFICATION

The present invention is directed to a method and apparatus for enhancing natural microbial biodegradation of organic compounds present in contaminated sediment.

BACKGROUND OF THE INVENTION

Bioremediation of groundwater and soils is a growing industry. As long as the treatment is preceded by an analysis of the treatability and toxicity of the site, it is a promising remedial option. Some toxins cannot be treated by biodegradation, but the cost of assessment is justifiable in that a detailed preassessment is substantially less expensive than excavation and chemical or physical treatment.

Bubbling the water column with oxygen has been proposed as a method of oxygenating the sediment. Some lake aeration treatments in Germany successfully oxygenated sediments but treatment with pure oxygen of some lakes in Switzerland did not oxygenate sediments. The engineering techniques are not completely developed, the treatment time may be long, and recovery difficult to predict accurately.

There exists a need for a sludge treatment process capable of being performed in-situ without stirring up the sediment into the water column and which permits a relatively large area to be treated quickly.

SUMMARY OF THE INVENTION

One object of the embodiment of the present invention is to provide an improved method for treating

SUBSTITUTESHEET sludge and an improved apparatus for effecting the method.

Another object of one embodiment of the present invention provides, a method of effecting natural microbial biodegradation of polynuclear aromatic hydrocarbons and petroleum hydrocarbons in sediment containing microbes and polynuclear aromatic hydrocarbons, and petroleum hydrocarbons characterized in that the method comprises the steps of: providing a biochemical oxidant for detoxifying a microbial toxin produced during microbial biodegradation of the polynuclear aromatic hydrocarbons and petroleum hydrocarbons; contacting the sediment with the oxidant to detoxify the toxin; and effecting microbial biodegradation of the polynuclear aromatic hydrocarbons and petroleum hydrocarbons.

The process of microbial decay results in the production of hydrogen sulphide. The presence of this compound generally impedes the biodegradation of the compound. The addition of a biochemical oxidant e.g. a bivalent alkaline earth chloride or nitrate or monovalent nitrate have been found useful.

By oxidation of the inhibitor, substantial success was realized in the reduction of toxins in the sediment. The successful results were compounded by the fact that the sediment was contacted at a plurality of locations. The overall process is continuous such that the treatment of the sludge can be effected quickly over a large area.

Nutrients may be added with oxidant concurrently or conterminously. Further, the addition of emulsifier surfactants, or other suitable treatment aids may be employed. Depending on the specific site variables, a pretreatment may be desirable in order to increase the efficiency of the procedure.

Apparatus suitable for facilitating maximum exposure of the oxidant to the sediment includes a dispensing arrangement therefor for dispensing the oxidant into the sediment in at least two locations simultaneously.

Thus, according to a further object of the present invention there is provided an apparatus suitable for treating sediment in a water body, the sediment containing chemical pollutants, comprising: a first dispensing means adapted for dispensing a treatment compound into contact with the sediment to be treated at a first level; a second dispensing means level adapted for dispensing the treatment compound within the sediment at a second level; each of the dispensing means having means for connection with a supply of the treatment compound; and support means for supporting the first dispensing means and the second dispensing means.

In accordance with one object of one embodiment of the present invention there is provided a method of effecting compaction of sediment containing microbes, polynuclear aromatic hydrocarbons and petroleum hydrocarbons, comprising: providing a biochemical oxidant for detoxifying a microbial toxin produced during microbial degradation of the polynuclear aromatic hydrocarbons and petroleum hydrocarbons; providing a fermentation by-product organic amendment; contacting the sediment with the oxidant and the fungal organic amendment; effecting microbial degradation of said polynuclear aromatic hydrocarbons and petroleum hydrocarbons; and compacting said sediment by evolution of gaseous by¬ products evolved from contact of said oxidant and amendment with said sediment.

In accordance with a further embodiment of the present invention there is provided a method of effecting natural microbial biodegradation of polynuclear aromatic hydrocarbons and petroleum hydrocarbons in sediment containing microbes and polynuclear aromatic hydrocarbons and petroleum hydrocarbons, comprising the steps of: providing a biochemical oxidant for detoxifying a microbial toxin produced during microbial biodegradation of the polynuclear aromatic hydrocarbon and petroleum hydrocarbons; providing a fermentation by-product organic amendment; contacting the sediment with the oxidant and the organic amendment; and effecting microbial degradation of the polynuclear aromatic hydrocarbons and petroleum hydrocarbons.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of one embodiment of the apparatus of the present invention; Figure 2 is an enlarged perspective view of one embodiment of the sediment treatment apparatus;

Figure 3 is a section along line 3-3 of Figure 2;

Figure 4 is an enlarged view of the mounting and fluid distribution for the sediment treatment apparatus;

Figure 4A is a plan view of the sediment treatment apparatus support;

Figure 4B is a schematic illustration of the apparatus in use;

Figure 5 is a series of graphs illustrating the concentrations of various contaminants;

Figure 6 is a schematic illustration of the test area;

Figure 7 is a graphic illustration of the redox potential of St. Marys River sediment cores;

Figure 8 is a histogram illustrating the effect of ferric chloride on sediment hydrogen sulphide for the St. Marys River treatment;

Figure 9 is a histogram illustrating the ATP-TOX results from Sault Ste. Marie for the first ferric chloride sediment injection; Figure 10 is a series of histograms illustrating the sediment toxicity of photobacterium phosphoreum bioassay for data gathered at St. Marys River;

Figure 11 is a histogram illustrating the Daphnia magna bioassay results illustrating the average percent survival;

Figure 12 is a graph illustrating the percent mortality for the DMSO/methanol sediment extract;

Figure 13 is a histogram illustrating the average percent survival for Daphnia magna bioassay results for the Hamilton Harbour Stelco Hotspot site #1;

Figure 14 is a histogram illustrating the average percent survival for Daphnia magna bioassay results for the Hamilton Harbour Stelco Hotspot site #2;

Figure 15 is a histogram illustrating the average percent survival for Daphnia magna bioassay results for the Hamilton Harbour Stelco Hotspot site #3;

Figure 16 is a histogram illustrating the results of Figures 13, 14 and 15;

Figure 17 is an illustration of the toxicity severity of Hamilton Harbour;

Figure 18 is an illustration of the toxicity of Hamilton Harbour sediments for photobacterium;

Figure 19 is an illustration of the Hamilton Harbour sediment injection site; Figure 20 illustrates data generated in denitrification experiments for bottle incubations;

Figure 21 illustrates data generated in denitrification experiments for 250 ml bottle incubations;

Figure 22 illustrates data generated in denitrification experiments for 2 L bottle incubations;

Figure 23 illustrates data generated in denitrification experiments for 250 ml bottle incubations;

Figure 24 illustrates data generated in denitrification experiments for 2 L bottle incubations;

Figure 25 illustrates the biodegradation of the sixteen priority pollutant polynuclear aromatic hydrocarbons;

Figure 26 illustrates the denitrification data comparing Hamilton Harbour Deep Basin, Stelco Hotspot and St. Marys River;

Figure 27 illustrates the effect of the nitrate treatment on the Photobacterium;

Figure 28 illustrates headspace GC/MS analysis for a variety of organic compounds for a control and for data gathered after nitrate treatment; and Figure 29 illustrates the biodegradation of volatile toxins in the Dofasco boatslip before and after treatment.

Figure 30 is a graphical representation of gas production based on 1992 compiled data with reactors having sediments from St. Marys River, Red Rock and Deep Basin of Hamilton Harbour in the absence of any organic amendment treatment;

Figure 31 is a graphical representation of volume of gas produced versus elapsed time in days for the St. Marys River reactor;

Figure 32 is a graphical representation of volume of gas produced versus elapsed time in days for the Toronto Harbour reactor;

Figure 33 is a graphical representation illustrating the effect of sediment treatment on sediment oxygen demand for the Spadina Avenue Boatslip and St. Marys River sediments;

Figure 34 is a graphical representation of the total petroleum hydrocarbons biodegraded in reactors with sediments from the Spadina Avenue Boatslip;

Figure 35 is a graphical representation of the concentrations of a variety of polynuclear aromatic hydrocarbons for the Spadina Boatslip;

Figure 36 is a graphical representation of the total petroleum hydrocarbon biodegradation in sediments from Embayment A Toronto reactor; Figure 37 is a graphical representation of the polynuclear aromatic hydrocarbon biodegradation in reactors with sediments from Embayment A Toronto;

Figure 38 is a graphical representation of polynuclear aromatic hydrocarbon biodegradation reactors with sediments from Embayment A Toronto illustrating the priority pollutant polynuclear aromatic hydrocarbons;

Figure 39 is a graphical representation of total petroleum hydrocarbon biodegradation in reactors with sediments from Dofasco Boatslip;

Figure 40 is a graphical representation of petroleum aromatic hydrocarbon biodegradation in reactors with sediments from Dofasco Boatslip;

Figure 41 is a graphical representation of the concentration of fifteen priority pollutant polyaromatic hydrocarbons for the Dofasco Boatslip;

Figure 42 is a graphical representation of the naphthalene concentrations for the Dofasco Boatslip; and

Figure 43 is a graphical representation of applied nitrate dose and methane and sulphate fluxes.

INDUSTRIAL APPLICABILITY

The present invention has applicability in the sediment remediation field.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 illustrates a first embodiment of the present invention situated on a carrier vessel. The apparatus includes rotatable lifting apparatus 10 having a main support platform 12 mounted to the carrier vessel 14 in a known manner. Load bearing masts 16, 18 are connected to the platform 12. A winch cable system 20 includes winches 22 and extends over pulleys 24 on masts 16 and 18. One of the winch cables 20 include a connecting member 26 suitable for connection with the sediment treatment apparatus, generally denoted by numeral 30. A support system is provided for supporting and assisting in the positioning of the treatment apparatus 30, (discussed hereinafter) .

Treatment apparatus, best illustrated in Figures 2 and 3, includes an elongate hollow spray bar 32 having opposed ends 34 (Figure 1) and 36. Spray bar 32 includes a plurality of nozzles 38 distributed along the length of bar 32 in a spaced and aligned relation. Nozzles 38 are inclined downwardly relative to a horizontal plane. A second set of nozzles 40 are distributed along bar 32 in spaced and aligned relation radially spaced from nozzles 38. Both nozzles 38 and 40 are in fluid communication with spray bar 32.

As illustrated, the treatment apparatus 30 comprises of a plurality of similar units and accordingly the description will be limited to one such unit.

Spaced above bar 32 is a mounting member 42 comprising a metal tube having opposed ends 44 (Figure 1) and 46. A plurality of members 42 are connected in end- to-end relation by suitable fasteners. Each remote or terminal end as well as the end connection between mounting members 42 includes a spacer member 48, which spaces members 42 from spray bar 32, and serves to impart support to the spray bar 32. Connection of spacer members 48 to member 42 and bar 32 is achieved by suitable fasteners, welding etc.

Each mounting member 42 includes a plurality of arcuate fingers 50 each connected thereto by bolts 52. Fingers 50 are arranged in longitudinally aligned and spaced relation. Each finger 50 has a generally sinusoidal configuration and is composed of rigid metal bent into shape. The shape of each finger 50 permits resilient flexibility. A free end 54 of each finger 50 is laterally and vertically spaced from the spray bar 32.

Each finger 50 includes, spaced from end 54 thereof, a nozzle mounting 56 for mounting a nozzle 58. A conduit 60 extends between and connects, nozzle 58 with nozzle 40 such that fluid communication is established.

Treatment fluid is distributed to each spray bar 32 by conduit 62 connected to each spray bar 32 inwardly of the end thereof by a swivel type connector 64. Each conduit 62 terminates for fluid connection with a main feeder conduit 66 (Figure 1) . Conduit 66 is connected to a fluid treatment supply drum 68 centrally located on the carrier vessel to act as ballast. A pump (not shown) may be positioned intermediate of drum 68 and feeder conduit 66 or the fluid may be distributed by negative pressure.

Treatment fluid travelling through each spray bar 32 will be dispensed through nozzles 38 and nozzles 40.

At least the spray bars 32 adjacent the terminal sections thereof further include frame mounts 70 for releasably coupling the treatment apparatus 30 to a frame 72.

Figure 4 illustrates an enlarged view of the attachment of the end of frame member 74 to spray bar 32 (removed for clarity) as is generally illustrated in Figure 1. Fastener 76 links a flange 78 on member 74 to frame mount 70. The frame 72 may include a plurality of members 74 which converge, and the member thereof will vary depending on the size of the treatment apparatus. The frame 72 permits easy manipulation of the apparatus from a submerged position to a storage position, the latter position being illustrated. Frame 72 includes a connection site 80 for connection with connecting member 26 on winch cable 20.

Figure 4A illustrates the hangar assembly 90 for positioning the assembly 30 into the sediment at the desired position.

The assembly 90 includes a main load bearing member 92 which terminates at a horizontally disposed bracket 94 for connection with spray bar 32 (not shown) . Connection to spray bar 32 may be by any suitable means, e.g. clamps, bolts etc.

Bracket 94 and member 92 are further reinforced by braces 96 extending therebetween.

In order to permit treatment of sediment in a variety of situations where the depth requirement varies, load bearing member 92 may include a plurality of telescopic sections of tube 98 or may be extended by progressive manual connection of further lengths of tubing sections 98.

Load bearing member 92 may be pivotally connected to the load bearing masts 16 and 18, described herein previously, or may be connected directly to platform 12 for easy manipulations of member 92. The specific mounting position of member 92 will depend upon the specific parameters in the treatment area, e.g. water depth etc.

Generally, the tubing sections 98 may comprise rigid aluminum material or other suitable corrosion resistant materials. This material provision is additionally applicable to the overall assembly 90 and frame 72.

In operation, the treatment apparatus 30 is moved from the storage position shown in Figure 1 to the use position shown in Figure 4B where the apparatus is submerged below the surface of the water, W, to contact within the sediment bed, S.

In this position, both the spray bars 32 and the fingers 50 contact the sediment, S. Fingers 50 permit deeper penetration of the nozzles 58 and more specifically the treatment material dispensed therethrough, into contact with the sediment. Nozzles 38 dispense the treatment material in a second position spaced from that of the treatment supplied by nozzles 58. This two-point injection system has a dramatic effect on the sediment detoxification as well be evinced by the data discussed hereinafter. Apparatus 30 is dragged along the sediment bed as the carrier vessel travels the area to be treated. Fingers 50 are unaffected by irregular bed topography, small debris etc. and when encountered fingers 50 simply flex and return to a normal disposition as the apparatus continues to be advanced along the sediment bed.

In preferred form, the overall length of the apparatus is eight (8) metres with the spacing between nozzles 38 and 58 being between 10 and about 20 centimetres. Such spacing permits uniform dispersion within the sediment as opposed to localized areas of treatment.

Treatment fluid injection rate into the sediment may be timed with the carrier vessel speed. In an alternate embodiment, the apparatus 30 and ancillary equipment (winch, loud bearing masts etc.) as well as the submerging procedure may be effected by robotics controlled from the shore or at a point distant from the treatment area to reduce the exposure of human workers to hazardous sediment material.

The use of monitoring means e.g. sonar equipment, cameras, ultrasonic equipment etc. are all envisioned for use with the apparatus in order to monitor gross sediment topography irregularities or obstacles with which the apparatus 30 cannot contend.

Still further, the connection points between spray bars 32 and between mounting members 42 may be hinged to permit folding of the apparatus 30. In addition, the apparatus may be telescopic. The examples illustrated teach a two-point treatment injection system and it will be clearly understood that a multiplicity of injection points may be provided simply by, for example, the addition of a further series of fingers having a greater length than the previous series.

GENERAL EXAMPLE 1 - FERRIC CHLORIDE INJECTION

Earlier laboratory trials with Hamilton Harbour sediments indicated that the addition of iron reduced toxicity to Photobacterium phosphoreum, Daphnia magna. Salmo gairdneri, Pi ephales promelas, and Hexagenia limbata. The seasonal change in sediment toxicity also seemed related to a change in redox, albeit the relationship was not firmly established. Also there was a correlation between the toxicity of the sediments to Daphnia magna and the chemical oxygen demand of the sediments. The most appropriate hypothesis to explain these observations is that much of the acute toxicity of the sediments of Hamilton Harbour was caused by reduced chemicals, probably hydrogen sulphide.

Hydrogen sulphide is very toxic. The LC₅₀ for various species are: Assellus 1.07 mg/L, Crangonvx 0.84 mg/L, Gammarus 0.059 mg/L, Baetis 0.020 mg/L, Ephemera 0.361 mg/L, and Hexagenia 0.111 mg/L. Chronic analysis indicates that no-effect levels are about 10% of the LC₅₀.

Samples were collected on several trips to St. Marys River and several trips to Hamilton Harbour with Ponar (Sault) or Shipek (Hamilton) grab samplers, TechOps corers, and sediment traps. The sediment traps were deployed a metre about the sediments to determine if the sediment injection equipment resuspended sediments. In the St. Marys River, four traps were set at one upstream site and four traps were set at one site downstream of the treatment area.

All St. Marys River samples were stored in a cold room and processed for shipping on ice, i.e., cores were extruded there at 1 cm intervals. Hamilton Harbour samples were brought back to the institute within hours of sample collection. All samples were chilled and processed quickly, i.e., all bioassays were processed within days of sample collection. Sediment samples were subsampled; half was freeze dried for metal analysis and half was frozen and retained for organic analysis.

The ATP-TOX method of Xu and Dutka (1987) was used oh 10% DSMO 10% methanol elutriates. Equal volumes of sediment and DMSO were mixed together and shaken vigorously by hand for 2 minutes. The homogenized slurry was centrifuged for 20 minutes at 10000 rpm. This system uses the measurement of ATP as indication of microbial growth. If when compared to a control, a sample inhibits ATP production (i.e., growth) , a toxic effect is assumed.

Daphnia magna bioassays were done on aqueous elutriates. Within two weeks of collection all samples were extracted with equal volumes of distilled water on an end-over-end shaker for 16 h. After extraction, sediment extracts were centrifuged for 20 min at 1000 g. Elutriates were centrifuged, not filtered. Filtration can remove colloidal material that would not settle from disrupted sediment and that may contain toxic metallic or organic contaminants. Ten Daphnia less than 24 h old were introduced to 25 mL of test medium and placed in a 25°C incubator for 48 h. A 16 h light and 8 h dark photoperiod was used. Prior to all experiments, pH and dissolved oxygen were measured and if the oxygen concentration was less than 8 mg/L, the sediment extracts were bubbled with purified air for 16 h. If more than 10% of the control Daphnia died within 48 h, the experiment was repeated.

Photobacterium bioassays were run on whole sediments (Brouwer et al. 1990). Dilutions for LC₅₀ analysis were done with clean sediments from an organic rich sediment from a marsh near Long Point, Lake Erie.

Table 1

PAH Concentrations in Surficial Sediment of Bellvue Marine Park Area

Sample Range (ng/g)

Naphthalene 3137 - 6878

Acenaphthylene 152 - 318

Acenaphthene 169 - 360

Fluorene 356 - 540

Anthracene 1913 - 3425

Phenanthrene 478 - 1227

Fluoranthene 2599 - 6831

Pyrene 2021 - 5485

Chrysene 1068 - 3269

Benzo (a) anthracene 1353 - 3680

Benzo (b) fluoranthene 2004 - 2223

Benzo (k) fluoranthene 1512 - 2202

Benzo (a) pyrene 964 - 3114

Dibenzo (a,h) anthracene 275 - 1040

Indeno (1,2,3-cd) pyrene 130 - 411

Benzo (ghi) perylene 370 - 1214

Total PAHs 16989 - 42019

Table 2

PCB Concentrations in Surficial Sediment of Bellevue Marine Park Area

Sample Range

(ngg)

PCB 18 ND -0.66

PCB 52 ND -5.13

PCB 49 ND -5.43

PCB 44 ND -3.69

PCB 101 2.48 -5.77

PCB 151 ND - 9.23

PCB 118+149 2.29 - 15.57

PCB 105 ND - 1.92

PCB 138 2.91 -6.36

PCB 183 ND -0.85

PCB 194 ND -0.85

Total PCB 80.43 -299.28

SUBSTITUTE SHEET t Table 3

Organic Contaminant Concentrations in Surficial Sediment of Bellevue Marine Park Area

Sample Range Sample Range

(ng/g) (ng/g)

1,3 DCB ND Aldrin ND

1,4 DCB ND CCS ND

1,2 DCB ND g Chlordane ND

HCE ND o, p DDE ND

1,3,5 TCB ND a Endosulfan ND

1.2,4 TCB ND a Chlordane ND

1,2,3 TCB ND t Nonachlor ND

1,2,3,5 TECB ND Dieldrin ND

1,2,4,5 TECB ND p,p' DDE 1.97-3.17

1.2,3,4 TECB ND o-p'DDD ND

PECB ND Endrin ND

2,3,4,6 TECB ND β Endosulfan ND

A BHC 1.66-4.14 p.p' DDD 1.22-3.32

HCB ND o,p' DDD ND

PECA ND Methoxychlor ND

Lindane ND Mirεx ND

Heptachlor ND

SUBSTITUTE SHEET >.

Table 4: PAHs in Hamilton Harbour surface sediments (0-1 cm) collected in 1991

Murphy HAMILTON HARBOUR PAHs cone, uq/q Sediment Samples Summer 1991 pg. 1 of 3 proc.blk site 41 site 80 site 47 site 76 site 74 site 9 site 2

NAPHTHALENE <0.01 0.61 0.24 3.86 0.11 0.15 1.14 0.15

ACENΛPHTHYLENE ND 0.12 0.02 1.27 0.02 0.04 0.20 0.03

<Λ ΛCENΛPHTHENE ND 0.05 0.02 1.53 0.03 0.04 0.25 0.06

__*_» FLUORENE ND 0.14 0.04 2.72 0.05 0.09 0.29 0.06

PHENANTHRENE <0.01 1.32 0.37 22.59 0.42 0.86 1.66 0.51

ANTHRACENE ND 0.20 0.03 5.01 0.07 0.18 0.41 0.08 I rπ FLUORANTHENE <0.01 3.38 0.86 50.36 0.85 1.86 4.33 1.02 ro rji PYRENE <0.01 3.01 0.76 41.07 0.74 1.61 4.04 0.88

BENZ(a)ΛNTHRACENE <0.01 1.66 0.39 33.54 0.47 0.82 2.56 0.40

CI IRYSENE <0.01 2.16 0.56 4.36 0.61 1.05 3.00 0.62

BENZO(B)FLUORANTHENE <0.01 6.27 0.05 57.34 0.76 1.83 0.20 0.34

BENZO(K)FLUORΛNTHENE <0.01 0.77 0.57 41.60 0.55 0.68 3.26 0.49

BENZO(A)PYRENE <0.01 2.40 ND 89.29 0.31 0.23 3.75 0.15

INDENO(1.2,3-cd)PYRENE ND 0.51 ND 179.22 0.17 ND 0.42 0.05

DIBENZ(a,h)ΛNTHRACENE ND 0.60 ND 16.85 0.13 ND 0.40 0.02

BENZO(qhi)PERYLENE ND 1.05 0.07 111.47 0.31 0.05 1.42 0.13

TOTALS <0.01 24.25 3.98 662.10 5.60 9.48 27.35 4.98

Table 4 cont: PAHs in Hamilton Harbour surface sediments (0-1 cm) collected in 1991

Murphy HAMILTON HARBOUR PAHs cone uq/q Sediment Samples Summer 1991 pq. 2 of 3 sile 25 sile 15 sile 45 site 9R site 57 sile 28 site 19 sile 55

NAPHTHALENE 2.39 0.31 1.43 0.68 0.46 0.71 0.04 0.09

ACENAPHTHYLENE

CO 0.76 0.11 0.46 0.14 0.22 0.24 0.01 0.02

ΛCENΛPHTHENE 0.26 0.11 0.54 0.17 0.14 0.18 <0.01 0.01

FLUORENE 0.76 0.14 0.96 0.20 0.28 0.36 0.01 0.02

PHENANTHRENE 4.18 0.95 8.12 1.19 2.56 2.93 0.07 0.15 O ANTHRACENE 1.06 0.19 2.21 0.24 0.16 0.18 0.01 0.05 re FLUORANTHENE 17.26 2.07 11.53 3.11 4.86 5.22 0.17 0.39

PYRENE 17.41 1.85 9.10 2.80 4.11 4.44 0.15 0.35

BENZ(a)ANTHRACENE 15.79 1.14 4.85 1.65 2.03 2.52 0.07 0.16 r r

CHRYSENE 16.15 1.37 5.33 2.04 2.53 2.77 0.09 0.22

BENZO(B)FLUORANTHENE 17.75 0.02 0.34 0.03 0.41 2.84 0.22 0.13

BENZO(K)FLUORANTHENE 17.57 0.99 4.69 1.89 1.73 1.48 0.08 0.17

BENZO(A)PYRENE 26.62 0.80 6.77 2.05 5.42 0.25 0.08 0.19

INDENOd ,2,3-cd)PYRENE 6.18 0.05 0.64 0.70 0.40 ND ND 0.01

DIBENZ(a,h)ANTHRACENE 3.03 0.01 0.31 0.12 0.05 ND <0.01 ND

BENZO(qhi)PERYLENE 12.44 0.16 2.19 0.65 0.30 0.12 ND <0.01

TOTALS 159.60 10.26 59.47 17.67 25.64 24.26 0.98 1.96

Table 4 cont: PAHs in Hamilton Harbour surface sediments (0-1 cm) collected in 1991

Murphy HAMILTON HARBOUR PAHs cone yg/q Sediment Samples Summer 1991 pq. 3 of 3 site 36 site 28R site 48 sile 29 site 53 site 37 site 61 site 61 R

NAPHTHALENE 0.83 1.00 84.82 0.41 0.36 1.17 0.65 0.84

ACENAPHTHYLENE 0.25 0.36 2.31 0.14 0.08 0.28 0.07 0.09

ACENAPHTHENE 0.17 0.20 14.24 0.10 0.06 0.18 0.16 0.21

FLUORENE 0.44 0.39 21.14 0.21 0.12 0.38 0.27 0.37

PHENΛNTHRENE 3.56 3.13 154.48 2.07 1.16 3.44 2.25 3.23

ANTHRACENE 1.10 1.00 56.41 0.52 0.27 0.87 0.38 0.55

FLUORANTHENE 6.76 5.79 167.90 3.77 2.21 6.28 3.20 4.72

PYRENE 5.68 4.90 139.67 3.21 1.91 5.37 2.70 3.95

BENZ(a)ANTHRACENE 3.05 3.21 90.37 1.85 0.98 3.07 1.44 2.10 ro

CHRYSENE 3.56 3.38 80.68 2.22 1.26 3.72 1.95 2.70

BENZO(B)FLUORANTHENE 1.07 3.70 154.33 3.30 1.66 6.11 5.06 4.71

BENZO(K)FLUORANTHENE 1.76 3.25 89.25 2.33 1.08 3.69 1.51 2.33

BENZO(A)PYRENE 2.62 3.99 133.00 2.42 0.93 4.34 2.03 3.11

INDENO(1 ,2,3-cd)PYRENE ND 5.97 304.70 0.92 0.21 1.24 1.16 2.92

DIBENZ(a,h)ANTHRACENE ND 0.74 37.94 0.30 0.07 0.38 0.36 0.70

BENZO(qhi)PERYLENE 0.00 2.19 135.42 1.12 0.35 1.82 1.17 2.41

TOTALS 30.91 43.19 1666.67 24.91 12.70 42.34 24.37 34.96

Table 5 PAHs in Ekman Dredge Samples - Steico Hotspot

February 1990 October 1990

Compound Dredge Dredge Dredge Dredge ^*Core Site #1 Site #2 Site #3 Site #1 Site #1

NAPHTHALENE 2718.9 2042.1 10263.5 5457.8 2925.7

ACENAPHTHYLENE 13.5 19.2 16.4 8.3 14.7

ACENAPHTHENE 19.9 6.0 60.0 27.9 3.3

FLUORENE 8.6 19.0 13.3 27.1 15.5

PHENANTHRENE 79.6 64.7 179.0 72.8 48.5

ANTHRACENE 24.8 22.9 53.6 25.7 17.7

FLUORANTHENE 78.1 54.7 139.1 59.1 38.2

PYRENE 42.9 29.2 76.3 42.6 27.6

BENZOaANTHRACENE 41.1 24.6 59.4 20.0 12.3

CHRYSENE 40.3 23.1 55.0 20.1 12.5

BbFLUORANTHENE 42.0 21.0 58.1 14.5 7.2

BkFLUORANTHENE 26.4 15.7 30.1 9.5 4.9

BaPYRENE 38.9 20.7 49.7 12.9 6.4

INDENOPYRENE 24.3 13.1 30.5 8.6 4.3

DIBENZOANTHRACENE 4.6 3.1 5.9 2.5 1.6

BENZOPERYLENE 22.0 11.1 27.6 8.1 3.6

TOTAL (ug/g) 3225.7 2390.1 11117.6 5817.5 3143.9

'Combined

SUBSTITUTE SHEET SEDIMENTS AT THE BELLEVUE PARK SITE, ST. MARYS RIVER

Unlike Hamilton Harbour, metals (Figure 5) and the 16 priority pollutant polynuclear aromatic hydrocarbons (PAHs, Table 1) are comparatively dilute at the Bellevue Park test site in the St. Marys River (Figure 6) . However, sediment samples from near Bellevue Park have high concentrations of oil and grease (1.4%, 1.6% and 2.4%) and wood fibres.

A high concentration of a complex PAH (retene, 2 g/g) was found in the St. Marys River sediments. Retene can occur naturally from degradation of conifers but it can also be associated with pulp and paper manufacturing. The concentrations of many of the priority pollutant chlorinated organic compounds is near or at background levels (Tables 2 and 3).

Decay of the wood fibre and other wastes results in a reducing environment as indicated by the black colour, high ammonia (1.5-2.3 mg/L), and low redox (Figure 7). Note that the deeper sediments are more oxic. This observation reflects the relatively recent discharge of labile organic wastes over older more oxic sediments. Also note that the redox of the sediments changes seasonally. By November the surface sediments have become oxygenated (Figure 7) . It is a fortunate situation in that oxidation treatment of the surface sediments could not be compromised by diffusion of reduced materials such as hydrogen sulphide from deeper sediments. Also the required depth of treatment is only 15 cm. Table 6

Summary of Sediment Trap Data -St. Marys River Chemical Treatments

July 8 , 1991 Oct. 10, 1991

Upstream Downstream Upstream Downstream

0.122 0.182 0.066 0.049

0.140 0.169 0.064 0.029

0.154 0.144 0.047 0.074

0.081 0.158 0.048 0.081

0.124 0.163 Average 0.056 0.058

All data are in grams of dry sediment. No significant differences between upstream and downstream.

SUBSTITUTE SHEET The highest observed concentration of hydrogen sulphide in the sediment was in June (Figure 8) . By the end of August most of the hydrogen sulphide had been oxidized. The sediment treatment with ferric chloride greatly reduced the concentration of hydrogen sulphide.

The ATP-TOX bioassay indicated a seasonal change in toxicity (Figure 9) that closely matched that of the hydrogen sulphide concentration. Also, the ferric chloride treatment reduced the toxicity of the ATP-TOX bioassays in tandem with the hydrogen sulphide complexation. Photobacterium phosphoreum bioassays also indicated a seasonal change in toxicity but they were not done as intensively as the ATP-TOX bioassays (Figure 10) . Daphnia magna bioassays with aqueous extracts indicated no toxicity (Figure 11 but some DMSO extracts with Daphnia could measure toxicity (Figure 12).

Two other bioassays indicated little or no toxicity. Dilution bioassays with Hexagenia (mayfly nymphs) from four field trips in 1991 (February, June, July, and August) indicated no toxicity. Bioassays with Lactuca sativa (lettuce) detected little toxicity. These latter bioassays are not sensitive to hydrogen sulphide toxicity.

Three sets of Daphnia toxicity dilution experiments in Hamilton Harbour also observed a seasonal change in sediment toxicity (Figures 13, 14 and 15). Some variation exists and the trends are more obvious by looking at the average toxicity (Figure 16) . In winter, these sediments have little toxicity. However, if these winter samples are purged with nitrogen, then sealed for a month to go anoxic, then bubbled with air for 2-3 h to oxygenate them, they are highly toxic. This length of oxygenation provides oxygen saturation but it is less than the half life of hydrogen sulphide oxidation (19 h) .

By late fall, the sediment samples from the Stelco Hotspot were still highly toxic. These observations differ from the St. Marys River sediments where hydrogen sulphide toxicity was almost gone by late August. The differences in extremes of hydrogen sulphide concentrations support the hypothesis that the Stelco Hotspot with 100 mg/L of hydrogen sulphide will stay toxic for much longer than the St. Marys River sediments with 4 mg/L hydrogen sulphide.

New toxicity maps with Daphnia magna (Figure 17) and Photobacterium phosphoreum (Figure 18) indicate much less toxicity than earlier maps. The new maps are done from analyses of surface sediment (0-1 cm) , whereas the old maps were done from analyses of Ek an dredge samples (0- 15 cm) . In part, the surface sediments have less contaminants, but the deeper sediments have less access to oxygen and anoxic decay produces hydrogen sulphide.

If the acute toxicity is controlled by hydrogen sulphide, then no biodegradation occurs in the deeper sediments and some occurs at a suppressed rate in the most recent sediments. The proof of this last hypothesis is found in the PAH data. The surface sediments have much less naphthalene than the deeper sediments (Tables 4 and 5) .

Two sediment injection trials were conducted in the St. Marys River near Bellevue Park. The first trial was relatively successful but modifications were made to improve efficiency before the second injection trial. The system, described previously, for injecting iron into sediments was built and tested for the first time in the St. Marys River on July 10, 1991.

Sediments were not resuspended into the water column. A pressure wave proceeding the injection bar raised the sediments about 20 cm, but they fell back with minimal resuspension to the upper waters. Sediment trap analysis confirms that no sediment moved to the water surface (Table 6) . A large amount of gas reached the surface and small patches of oily film formed. Some macrophytes (primarily Elodea canadensis. were broken by the injection bar, but most remained intact. The sediments ATP-TOX bioassay indicated a reduction in acute toxicity after the ferric chloride treatment (Figure 9) .

A second ferric chloride injection was done north of the first site to an area 200 m by 36 m. Smaller nozzles (0.031 inch diameter orifice) were used to maintain a high back pressure in the injection manifold and a constant flow through all the nozzles. Visual observations indicated that the surface 15 cm of sediments were treated.

EXAMPLE 2 - CALCIUM NITRATE INJECTION

The following reaction is mediated by bacteria:

5CH0₂O + 4N0₃ ^" = 2N₂ + 4HCO-^" + C0₂ + 3H₂0.

Surface sediments (1-50 cm) from the St. Marys River were collected near Bellevue Park as illustrated in Figure 6. Surface sediments (0-15 cm) were collected from the deep basin of Hamilton Harbour as illustrated in •Figure 19. Sediments were collected with either a Shipek dredge, or a TechOps corer. Samples were placed in either a fridge or 12°C incubator. In Sault Ste. Marie, samples were quickly placed in a cooler and stored in a fridge. Sediment cores were subdivided within 24 h. Sediment samples were placed in clean pails with lids and enough sediment was added to exclude air. Sample processing for bioassays included homogenization with larger mixer and subsequent handling in a glove box in a fu ehood. Sampling of reactors was done in a glovebox after purging it with nitrogen.

The microbial metabolism incubations were run using 300 mL BOD bottles with and without 100 mg N/L of calcium nitrate. Both 155 mL and 250 mL septum fitted bottles were used in subsequent trials for incubations with 500 mg/L N-N0₃. Biodegradation experiments were run in 155 mL glass bottles with serum caps and a 20 mL nitrogen headspace, with and without 500 mg/L N calcium nitrate. The nitrogen headspace was sampled with gas tight syringes after relatively short-term incubations (2-6 weeks) .

For all incubations, the sediments from the St. Marys River were mixed with deoxygenated water from St. Marys River and the Hamilton Harbour sediments were mixed with dechlorinated deoxygenated water to form a 50% slurry. The sediments were shaken continuously on an end-over-end shaker. In one trial to measure the production of ammonia, 2 L jars were used for incubations with 500 mg/L N-NO-; these sediments were shaken once a day. Sediment slurry was centrifuged and the supernatant was filtered and processed using an ion chromatograph to determine nitrate and sulphate concentrations. The pH of samples was measured with a pH meter. Ammonia was analyzed by colori etric analysis.

Volatile organic compounds in the headspace were measured by GC/MS. Each assay was processed with five replicate bottle incubations and the headspace subsamples were combined. Sediment samples for hydrogen sulphide analyses were frozen and then were purged with helium without any pH treatment; the hydrogen sulphide was trapped in a cold trap and injected for analysis into a GC/MS.

Sodium sulphate was used to dry the samples. Dichloromethane was used to extract the samples with 10 cycles/h in a Soxhlet extractor for 8 h with a water bath at 25°C.

Photobacterium bioassays were run on whole sediments. Dilutions for LC₅₀ analysis were done with clean sediments.

Results

Enhancement of Microbial Metabolism

St. Marys River Sediments.

Laboratory reactor experiments were successful in stimulating microbial metabolism in St. Marys River sediments with calcium nitrate. The microbial denitrification of nitrate was coupled to the rapid production of sulphate, (Figures 20 and 21) . The production of sulphate reflects the microbial oxidation of organic sulphur, hydrogen sulphide, and perhaps elemental sulphur. The 100 mg/L N-NO- dose was completely denitrified (Fig. 20) . The next experiment with 500 mg/L N-N0₃ resulted in incomplete denitrification of the added nitrate (Fig. 21) .

After two weeks of incubation, sediments treated with 500 mg/L N-N0₃ were bioassayed. They were toxic to Hexagenia. Based upon results from the second experiment (Fig. 22) , these sediments had a high concentration of nitrate (>300 mg/L N-NO-) .

Using larger containers (2 L) without continuous shaking, the utilization of nitrate was slightly slower than in Figs. 21 and 22) . Since these incubations used 50% slurries, these incubations indicate that the optimal in situ does is about 350 mg/L N-N0₃. Very little ammonia was produced during these incubations (Figs. 23- 24) . Other trials indicated that phosphorus was not limiting microbial denitrification, that addition of iron did not suppress denitrification, and that the pH did not decrease significantly.

In one year long incubations with sediments from the St. Marys River, nitrate treatment resulted in biodegradation of about 60% of the polynuclear aromatic hydrocarbons (PAHs, Figure 25) . The numbers in Figure 25 refer to the molecular weight of the 16 priority pollutant polynuclear aromatic hydrocarbons.

Hamilton Harbour

The rate of denitrification in a sediment sample from the deep basin of Hamilton Harbour was slightly slower than in a sample from the St. Marys River (Bellevue site) , and much slower than in a sample from the Stelco Hotspot (Fig. 26) . In the sample from the deep basin of Hamilton Harbour, the denitrification resulted in the complete elimination of toxicity to Photobacterium (Fig. 27) .

Another simple physical change also occurs during treatments. The control samples are very flocculant and these sediments stay in suspension for days. The treated sediments are not flocculant; these sediments precipitate within three hours after shaking. The treatments must polymerize negatively charged organic colloids. This flocculation could be very useful.

The PAH data from headspace analysis is complex but highly encouraging. Headspace analysis of some samples indicates biodegradation of butenes, chlorobenzenes, toluene, benzene, and naphthalene at rates consistent with other studies. Other analyses indicate production of several compounds, indicating cleavage of smaller molecular weight compounds from larger compounds. There are about 30 analyses as complex as Figure 28.

Table 7 PAHs in solids after chemical treatment

Hamilton Harbour and Sault Ste. Marie Biodegradation Study Fall 1991

Hamilton Hamilton Hamilton Sault Sault Sault SEDIMENT ug/g Harbour Harbour Harbour Ste. Marie Ste. Marie Ste. Marie

Control FeCI3 N03 Control FeCI3 N03

NAPHTHALENE 0.77 0.96 0.90 4.14 2.37 4.51

ACENAPHTHYLENE 0.19 0.27 0.23 0.26 0.18 0.23

ACENAPHTHENE 0.21 0.26 0.25 0.41 0.28 0.37

FLUORENE 0.50 0.67 0.52 0.64 0.45 0.56

PHENANTHRENE 3.36 4.59 4.24 4.45 3.09 4.00

ANTHRACENE 0.70 1.00 1.01 1.31 0.93 1.08

FLUORANTHENE 5.84 7.85 7.25 10.13 7.17 9.46

PYRENE 4.05 6.70 6.24 8.44 5.97 7.90

BENZ(a)ANTHRACENE 2.90 1.52 3.50 5.60 4.23 5.38

CHRYSENE 4.39 5.78 5.28 7.89 5.60 7.66

BENZO(b)FLUORANTHENE 4.92 6.05 2.77 6.38 3.76 6.68

BENZO(k)FLUORANTHENE 4.00 4.93 4.19 5.17 3.71 5.43

BENZO(a)PYRENE 1.00 5.60 7.43 7.02 6.45 7.30

INDENOd ,2,3-cd)PYRENE 3.31 1.85 0.22 2.44 0.74 3.13

DIBENZ.a,h)ANTHRACENE 1.38 1.25 0.17 1.04 0.14 1.55

BENZO(α.h,i)PERYLENE 3.23 2.15 0.96 2.64 0.88 3.22

TOTAL 40.75 51.43 45.16 67.94 45.95 68.47

RETENE 0.20 0.12 0.15 24.79 18.96 23.32

SUBSTITUTE SHEET Table 8 PAHs in water after chemical treatments

Hamilton Harbour and Sault Ste. Marie Biodegradation Study Fall 1991

Hamilton Hamilton Hamilton Sault Sault Sault SUPERNATANT ng/l Harbour Harbour Harbour Ste. Marie Ste. Marie Ste. Marie Procedura

Control FeCI3 N03 Control FeCI3 N03 Blank

NAPHTHALENE 410.70 205.29 43.20 178.65 2076.06 1963.06 0.0

ACENAPHTHYLENE 145.07 79.12 8.40 20.00 35.76 33.89 ND

ACENAPHTHENE 247.89 71.76 ND 252.16 210.61 305.28 ND

FLUORENE 301.13 155.29 28.00 178.11 274.55 256.39 ND

PHENANTHRENE 1415.49 659.71 344.40 616.22 814.30 848.31 0.03

ANTHRACENE 58.28 617.26 ND 52.43 52.91 76.11 ND

FLUORANTHENE 790.99 365.88 434.08 635.57 719.52 854.81 0.02

PYRENE 444.79 99.12 109.64 413.78 332.48 467.81 0.01

BENZ(a)ANTHRACENE 45.92 16.76 22.00 78.57 45.03 85.53 0.01

CHRYSENE 108.73 61.21 84.48 147.22 93.70 164.53 0.01

BENZO(b) FLUOR ANTH EN E 113.49 69.68 56.56 88.54 87.97 141.50 0.02

BENZO(k)FLUORANTHENE 44.76 27.47 29.76 64.95 34.70 55.81 0.01

BENZO(a)PYRENE 70.14 48.53 19.72 17.30 69.42 55.28 0.01

INDENO(1 ,2,3-cd PYRENE 44.25 ND 51.32 ND 36.52 11.81 ND

DIBENZ(a,h)ANTHRACENE 28.68 ND 7.40 ND 11.00 ND ND

BENZO(q,h,i PERYLENE 41.69 ND 22.00 ND 10.18 15.00 ND

TOTAL 4312.00 2477.09 1260.96 2743.49 4904.70 5335.08 0.16

RETENE 69.30 ND 0.92 582.43 267.27 85.64 0.13

SUBSTITUTE S The PAH analysis of solids remaining after six weeks incubation with or without calcium nitrate indicated no significant biodegradation of naphthalene or other PAHs (Table 7) . Analytically, the discrepancy with headspace analysis is possible in that the headspace represents only a small fraction of the total PAHs. The headspace is in equilibrium with free, unbound, bioavailable compounds, but the particulate PAH analysis is done on samples extracted vigorously with dichloromethane in a Soxhlet apparatus.

Only a fraction of the total PAHs are analyzed in the routine 16 priority PAHs, no analytical techniques exist for very large molecular weight PAHs. Also for both sites there must be some PAHs locked in coal dust or other biologically inactive matrices. The interpretation would also vary between sites. For example, the proportion of PAHs in the aqueous phase in the St. Marys River incubations indicates enhanced production of naphthalene from larger compounds after the treatments (Table 8) . In the aqueous phase of Hamilton Harbour incubations, the treatments appear to enhance biodegradation of naphthalene (Table 8) . The uncertainties of PAH biodegradation have been resolved with longer incubations, and incubations with ¹⁴C- radioactively labelled naphthalene.

The addition of calcium nitrate to the sediments of the Dofasco Boatslip in 1992 resulted in the biodegradation of several organic compounds (mean of three samples, reductions as follows; toluene 80%, ethylbenzene 86%, m/p-xylene 76%, 3/4-ethyltoluene 89%, and dichloromethane 65%) (Figure 29) . Analysis indicates that 25% of the petroleum hydrocarbons were biodegraded in the Dofasco treatment.

The biodegradation of the PAHs (polynuclear aromatic hydrocarbons) , in the Dofasco boatslip was more complex. About 15% of 15 PAHs were biodegraded and the naphthalene content increased 196% .

Table 9

STELCO HOTSPOT SEDIMENT ANALYSIS BY PURGE AND TRAP GC/MS

PARAMETER ng/ml

1 ,1 -dichloroethylene 659.2 dichloromethane 14.3 trans-1 ,2 -dichloroethylene 11.3

1 ,1 -dichloroethane 97.2 cis-1 ,2-dichloroethylene 0.0 chloroform 13.0

1 ,1 ,1-trichloroethane 0.0 tetrachloromethane 0.0

1 ,2-dichloroethane 18.1 benzene 831.2 trichloroethylene 0.0

1 ,2-dichloropropane 0.0 dibromomethane 0.0 bromodichioromethane 0.0 toluene 596.8

1,1 ,2-trichloroethane 0.0 tetrachloroethylene 21.6 chlorodibromomethane 0.0

1 ,2-dibromoethane 0.0 chlorobenzene 0.0 ethylbenzene 1348.8 m/p-xylene 3002.0 o-xylene 1225.2 styrene 274.3 cumene (isopropylbenzene) 119.3 bromoform 0.0

1,1 ,2,2-tetrachloroethane 5.9 propylbenzene 112.9

1 ,3,5-trimethylbenzene 150.8

1 ,2,4-trimethylbenzene 14.1

3-ethyltoluene 1050.0

4-ethyltoluene 1247.2

2-ethyltoluene 1598.0

1 ,3-dichlorobenzene 10.3

1 ,4-dichlorobenzene 0.0

1 ,2-dichlorobenzene 0.0

1 ,4-diethylbenzene 191.7

1 ,2-diethylbenzene 9.3

1 ,3-diethylbenzene 191.7 naphthalene 35920.0 hydrogen sulphide 100000.0

SUBSTITUTE SHEET At first the ability of microbes to biodegrade organic wastes seemed less probable in Hamilton Harbour sediments than in sediments from the St. Marys River. Hamilton Harbour sediments have 10-100 times the concentration of metals. However, the rate of headspace naphthalene biodegradation is similar in sediments from Hamilton Harbour, St. Marys River, and samples from other sites. Rates of denitrification in the St. Marys River sediments, Hamilton Harbour, and other sites in Germany are similar. At these sites, metals do not appear to suppress microbial biodegradation; many of the volatile organic compounds that were detected in the Hamilton Harbour Hotspot (Table 9) are biodegradable.

COMPARISON WITH FERRIC CHLORIDE TREATMENT Ferric chloride is a weaker oxidant than calcium nitrate. To achieve the equivalent oxidation potential of a 0.5% solution of calcium nitrate would require that the sediments become a 10% ferric chloride solution.

Chlorinated Phenols in St. Marys River Sediment Core - Julv 8, 1991

Sample ID (core Depth - cm) 0-1 6-7 12-14 14-16 16-18 22-24

Chlorinate Phenols

(μg/kg dry weight) ND ND ND ND ND ND

2,6-chloro-phenol ND ND ND ND ND ND

2,4-chloro-phenol ND ND ND ND ND ND

3,5-chloro-phenol ND ND ND ND ND ND

2,3-chloro-phenol ND ND ND ND ND ND

3,4-chloro-phenol ND ND ND ND ND ND

2,4,6-chloro-phenol ND ND ND ND ND ND

2,3,6-chloro-phenol ND ND ND ND ND ND

2,4,5-chloro-phenol ND ND ND ND ND ND

3,4,5-chloro-phenol ND ND ND ND ND ND

2,3,5,6-chloro-phenol ND ND ND ND ND ND

2,3,4,5-chloro-pheπol ND ND ND ND ND ND

Penta-chloro-phenol ND ND ND ND ND ND

4,6-chloro-guaiacol ND ND ND ND ND ND

4,5-chloro-guaiacol ND ND ND ND ND ND

3,4,5-chloro-guaiacol ND ND ND ND ND ND

4,5,6-chloro-guaiacol ND ND ND ND ND ND

3,4,5,6-chloro-guaiacol ND ND ND ND ND ND

3 ,5-chloro-catechol* * ND ND ND ND ND ND

2,3,4,6-chlorophenol** ND ND ND ND ND ND

4,5-chloro-catechol ND ND ND ND ND ND

3,4,5-chloro-catechol ND ND ND ND ND ND

3,4,5,6-chloro-catechol ND ND ND ND ND ND

6-chloro-vanillin ND ND ND ND ND ND

5,6-chloro-vanillin ND ND ND ND ND ND

Tri-chloro-syringol ND ND ND ND ND ND

4,5 Dichloro-veratrole ND ND ND ND ND ND

3,4,5 Dichloro-veratrole ND ND ND ND ND ND

Tetra-chloro-veratrole ND ND ND ND ND ND

** these compounds coelute ND not detected

SUBSTITUTE SHEET Acute toxicity is caused by hydrogen sulphide and it is readily oxidized by denitrification of added calcium nitrate. The oxidized sediments produce no toxicity to Daphnia magna, Hexagenia limbata, Escherichia coli, or Lactuca sativa. Many chlorinated compounds often associated with pulpmill wastes were not detected (Table 10) .

The concentration of PAHs is relatively low (Table 3. The high concentration of organic matter found in the sediments f the St. Marys River could reduce the bioavailability of PAHs as has been found at other sites.

St. Marys River

The St. Marys River contains large quantities of contaminated sediments. Oil and grease contamination appears responsible for the absence of Hexagenia in parts of the St. Marys River. The remedial action plan for the St. Marys River describes floating mats of sediments that are formed by the production of gases produced by anoxic decay. The St. Marys River received effluents with a high biological oxygen demand from the Algoma Steel mill, poorly treated sewage and large quantities of wood fibre (1968 suspended solids' loadings from St. Mary's Paper 23,800 kg/d, St. Marys River RAP 1992). It is likely that much of the toxicity of the sediments of the St. Marys River is caused by a low redox potential and products of anoxic decay, such as hydrogen sulphide. Furthermore, the anoxia will stabilize some organic contaminants.

Toronto

Two sites were sampled from Toronto Harbour: The more contaminated site was the Spadina Boatslip and the second was part of Tommy Thompson Park. The park is made up to three sections; the eastern headlands, the northern peninsulas and the diked areas. The northern peninsulas form four embayments (A to D) . Embayment A was formed in 1973 from the deposition of dredged material by the Toronto Harbour Commission. The material consists mainly of dredgate from both the inner and outer harbours. It has a surface area of about 7.0 hectares with a maximum water depth of 4.6 m (as of 1973). The embayment has a 95 m opening to the main channel, a maximum length of 350 m and a maximum width of 230 m. The sediments in Embayment A are moderately contaminated with oil and grease, PAHs, and some metals.

1992 Field Treatments

About 5000 m² of sediments at the south west corner of the Dofasco Boatslip were treated in 1992. On July 28, and September 15-17, 3.6 tonnes and 3.89 tonnes, respectively, of farm grade calcium nitrate were injected near Randle Reef (Stelco Boatslip) in about 10,000 m² of sediment July 15-17. A small area in the deep basin of Hamilton Harbour (21 m deep, 3,200 m²) , was treated with 0.38 tonnes and 2.16 tonnes of calcium nitrate on May 20 and July 30, respectively (Fig. 31) .

1993 Field Treatments

On April 27, 1993, 6 tonnes of calcium nitrate was injected into the sediments of the Dofasco Boatslip. On September 22, 1993, 5 tonnes of calcium nitrate and 8 tonnes of organic amendment were injected again at this site. On July 28, and July 30, 11.9 tonnes of calcium nitrate were injected at a site north of Randle Reef, Hamilton, Harbour. On June 23, 10.3 tonnes of calcium nitrate were injected at the Bellevue Park site, St. Marys River.

Surface sediments (0-15 cm) were collected with either a Shipek grab sampler, or a modified KB corer (Mudroch and MacKnight 1991) . Samples were returned to N RI, subdivided, and either placed in a fridge or freezer within 24 h. Bulk samples (10.4 L polypropylene buckets) were screened through 2 mm mesh and mixed with an electric mixer prior to separation. Samples for chemical analysis were frozen immediately. Control reference sediments consisted of samples collected from the treatment zone before treatment and samples collected from untreated areas next to treatment sites collected on the same day as those from the treated zone.

Volatile organic compounds were measured by GC/MS. A sample of 0.5-1.0 wet sediment was weighed and diluted with 5.0 mL of distilled water. The internal standards and surrogates were added. This volume was heated to 40°C and purged for approximately 10 minutes with helium gas. The sample was trapped on a Tenax-charcoal trap, run through a DB624 30 m column and analyzed on a GC/MS.

A 20 g sample of wet sediment was extracted with 80 mL dichloromethane for 5 hours on a shaker table. The extract was first dried by filtration through sodium sulphate and then concentrated by evaporation through a Snyder column. A GC was used to analyze the concentrate.

Liquid-liquid extraction was used to prepare sediment samples containing a high percentage of moisture (Dofasco boatslip) . A 20 mL sediment sample was diluted with 500 L of distilled water and extracted with dichloromethane. A Soxhlet extraction was used for sediment samples with relatively lower moisture contents (Stelco boatslip) . The sample was spiked with surrogate PAHs (6 deuterium isotopes) and extracted in a Soxhlet apparatus with an acetone-hexane mixture. The organic extract was base-partitioned. The aqueous medium was back-extracted with hexane and the organic fractions were combined. The combined extract was dried through sodium sulphate and concentrated. A GC/MS was used to analyze the concentrates. Recovery of the six deuterium labelled PAHs varied from 66% to 100% (mean 77%) .

Sediment samples for acid volatile sulphide (AVS) analyses were either processed the day of sample collection or were frozen and processed within two weeks. Wet- sediment (1.0 mL) was added to 5 mL of N-,-purged distilled water in a 15x125 mm test tube fitted with a two-hole rubber stopper containing a 6 mm o.d. gas delivery tube going to the bottom of the test tube, an outlet tube connected to the trap solution, and a syringe needle. The hydrogen sulphide trap solution was prepared by adding 3.5 L of sulphide anti-oxidant buffer (SAOB) stock solution (2 M NaOH, 0.1 M ascorbic acid and 0.1 m EDTA) to 10.0 mL of de-aerated distilled water. The apparatus was purged for about 5 in. with oxygen-free nitrogen gas after with 2.5 mL of 6 M HC1 was slowly added through a syringe needle inserted through the rubber stopper. Purging was continued for an additional hour at a flow rate of about 20 mL/min. To determine the sulphide concentration in the trap solution, the EMF was measured using a sulphide ion (ISE) (Orion 94-16) , a double junction reference electrode (Orion 90-02) , and a Corning Model 240 pH meter. Standard sulphide ion solution were used to prepare the calibration curve. The free or dissolved hydrogen sulphide in the sediment was determined without acid but the analysis was similar to the AVS. Wet sediment (30 mL) was added to 70 mL de-aerated distilled water in a 125 L polyethylene bottle. The sediment was kept in suspension using a magnetic stirrer for the duration of the purging process (1 hour) . Hydrogen sulphide in the nitrogen stream was trapped in SAOB solution (3.5 mL stock SAOB and 10.0 mL de-aerated water) and the resulting sulphide ion concentration was measured with the ISE.

Sediment samples were weighed into 50 mL polypropylene test tubes and deionized distilled water was added on an equal wet weight to volume basis. The tubes were capped, shook vigorously, placed on an end over end shaker for two hours. Subsequently, the tubes were centrifuged at 4000 rpm for 25 minutes. The supernatant was collected and filtered through a GF/F filter. Samples were spiked with sodium carbonate and sodium bicarbonate so that the final concentration of these salts was 0.03%. They were stored at 4°C for up to 48 h until analyzed on the Dionex model 2010i ion chromatograph.

Incubations were done in 250 mL brown glass bottles fitted with neoprene or butyl rubber stoppers. A #18 syringe needle was inserted through the stopper; a three- way stopcock attached to the needle permitted sampling of the gas and measurement of the gas produced. Samples were initially flushed with nitrogen or argon to maintain anoxic metabolism. All incubations were run in triplicate. Samples were enriched with various concentrations of calcium nitrate and an organic amendment to determine the optimal conditions for bioremediation. Samples were shaken once a week before measuring the gas produced. Gas samples were collected once a week as a signal of bacterial metabolic activity. The data on gas volume is shown as means; the error bars are smaller than the symbols. To measure gas samples, a syringe was used to connect the headspace of the glass bottle to a manometer. At times, the composition of the gas was analyzed in a gas chromatograph to measure the percent C0₂, CH₄, N₂, and 0₂.

Sediment oxygen demand in the reactors was calculated by adding the moles of oxygen present in the C0₂ and potential 0₂ consumption from the measured production of CH₄. We assumed methane would be oxidized in the following reaction:

5CH₄ + 80₂ = 2(CH₂0) + 3C0₂ + 8 H₂0

Bench-Scale Reactor Results

In the first set of reactors in 1991 and 1992, the optimal dose of nitrate was determined and that denitrification was the major oxidation reaction, that nitrites were not a significant byproduct and that ammonia concentrations did not increase. The first rates of biodegradation of coal tar were slow so we set out to determine what was controlling the rates of biodegradation in order to optimize the process. In a comparison of rates of gas production in reactors from Hamilton, the St. Marys River and Red Rock, the addition of nitrate greatly suppressed the production of gas from Red Rock sediments and slightly suppressed gas production from sediments from the St. Marys River (Fig. 30) . Although the Red Rock sediments were oxygenated by the nitrate, the rates of biodegradation were slow. Minimal effect in 6 weeks. It is believed that the calcium was inactivating phosphorus. The loading of phosphorus at these three sites matched the gas data. Hamilton has the highest phosphorus loading and seems unaffected by calcium addition. The St. Marys sediments indicate an intermediate suppression of gas production and the St. Marys River phosphorus loading is intermediate between Hamilton Harbour and Red Rock. The concentration of soluble reactive phosphorus in the porewater of sediments of Hamilton Harbour and Red Rock are about 2 mg/L and 0.005 mg/L, respectively. Inactivation of phosphorus by calcium has been observed in other bioremediation treatments. Some success was achieved with sediments from Red Rock with the addition of an organic formulation containing phosphorus (B-glycerophosphate disodium hexahydrate) ; about 46% biodegradation of TPSs in 198 days (none in control) .

The best organic amendments are exemplified by the by-products of fermentation, examples of which include soya products, fungal amendments, such as brewers yeast, etc. Others will be apparent to those skilled in the art. Brewers yeast, and more specifically, (1% spent brewers yeast) resulted initially in about 5-10 times as much gas production as the control treatments (Fig. 31 and 32) . The addition of yeast cell walls was also stimulatory (Figure 31) . The stimulation seems only partially related to organic nutrient availability; surfaces for adsorption of phosphorus may also be important. Dry yeast was as effective as wet yeast; thus, residual alcohol in the wet brewers yeast was not critical control; this difference continued for several months. The nitrate was utilized within the first seven weeks and the most rapid metabolic rates could not be maintained with a strong electron acceptor.

The composition of the gas provided further insights. Addition of nitrate without the organic amendment blocked methane production. The SOD was reduced by 90-95% (Fig. 33) . When sediments are treated just with nitrate, biodegradation is slow; thus, the suppression of SOD is not caused just by a lack of organic nutrients. It seems that the demonstrated inactivation of phosphorus is partly responsible for the suppression of SOD. When the organic amendment was added with nitrate, initially little methane was produced (>2% of C0₂ production) , but after 7-20 days, the production of both methane and carbon dioxide was stimulated.

Yeast amendment with nitrate greatly stimulated biodegradation of organic contaminants. In an earlier reactor from the St. Marys River, the biodegradation of TPHs and PAHs was relatively slow; about 60% biodegraded in a year (TPH data not shown, Fig. 25) . With two other sites, it was discovered that an organic amendment stimulated biodegradation of TPHs and PAHs about 10-fold. In laboratory incubations with sediments from two sites in Toronto, most of the PAHs biodegraded (Spadina Boatslip 44 day incubation, 90% and 82% of TPHs and PAHs biodegraded, respectively, Fig. 34 and 35; Embayment A, 150 day incubation, 78% of both TPHs and PAHs biodegraded, Fig. 36, 37 and 38) . Figures 34 and 36 illustrate that addition of heat-killed yeast (autoclaved) was an effective as addition of fresh yeast; thus, the yeast was not directly biodegrading contaminants. Laboratory incubations with sediments from the Dofasco Boatslip biodegraded about 78% and 68% of the oil (TPHs) and PAHs, respectively in 44 days (Fig. 39 and 40) . These Dofasco sediments were the most contaminated that we have worked with (PAH concentration of >2000 g/g) • Fortunately, the biodegradation of high molecular weight PAHs was as rapid as the biodegradation of low molecular weight PAHs. Phosphorus concentrations in Hamilton Harbour sediments are high from discharge of sewage and phosphoric acid.

Table 11

Properties of sediments obtained from Dofasco boatslip (Hamilton Harbour) and Spadina Ave. Boatslip (Toronto Harbour)

Property¹ Dofasco Boatslip MOEE SEL^* Spadina Ave. Boatslip

AVS (as mg H₂S/g) 8.0 0.30

HVS (as μg H₂S/g) 60 24

Total Sulphur (%) 1.8 0.33

Fe (mg/g) 278 40 27

Mn (mg/g) 6.3 1.1 0.39

Pb (mg/g) 3.15 0.25 0.57

Cu (mg/g) 0.20 0.11 0.18

Cd (μg/g) 62 10 7

Zn (mg/g) 22.3 0.82 0.64

TPH (mg/g) 11.8 1.5 23.8

PAH (μg/g) 450 1000* 133

Chromium (μg/g) 303 110

Organic C (%) 13.4 15.7

'All measurements are based on dry mass and are means of triplicate samples.

"Ontario Ministry of Environment and Energy, Severe Effects Level

'Denotes a tentative guideline (1993), calculation corrects for organic C content. This PAH concentration is much higher than recent proposed guidelines in the USA (45 μg/g, Long et al.

1994).

SUBSTITUTE SHEET Dofasco sediments were black with strong hydrocarbon odour. The extremely high concentration of acid volatile sulphide (AVS, 8 mg/g) confirmed redox measurements that these sediments were highly reduced. Some samples contained as much as 2.0% AVS (dry weight) and the mean concentration in the boatslip was 0.8%. These AVS concentrations were unusually high relative to other sites with anoxic sediments. Total sulfur concentration in boatslip was also higher than the two other areas of the harbour studied (Table 12) . Initially the nitrate treatment had no effect upon the concentration of AVS (data not shown) . However, the concentration of free H₂S was quickly reduced by the nitrate treatment. The concentration of H₂S in the pretreatment sediments (Table 13, mean 293 μg/L) would be very toxic to many organisms; the means concentration of hydrogen sulphide in the posttreatment samples (53 μg/L) would not be toxic to Hexagenia. Sediments in Hamilton Harbour and the St. Marys River indicate that sediments are more toxic when sulphur is reduced. In the St. Marys River, the addition of iron complexed hydrogen sulphide and reduced the sediment toxicity to E. Coli.

Table 12 Total Sulphur Content (mg/g dry weight.

Dofasco Deep Stelco Boatslip Basin Boatslip mean 18.07 5.20 3.97 standard deviation 6.87 .80 1.09 number of samples 9 12 12 Table 13 Free H₌S in Deep Basin Sediment (Nov. 25/92.* Site H₂S

Pretreatment Posttreatment

(μg/g⁾ (μg/L) (μg/g) (μg/L)

S-l 00..4444 110000 0.21 50

S-2 22..2255 449900 0.09 20

S-3 11..3399 229900 0.35 90

Mean 11..3366 229933 0.22 53

*Results of surface sediments (0-10 cm) expressed per unit dry weight (μg/g) or per volume of wet sediments

(μg/L) . By comparison, species sensitive to H₂S, like

Hexagenia limbata have acute (96 h) LC₅₀ of 165 μg/L

(Oseid and Smith 1975) .

The nitrate injection was most efficient at the Stelco site and deep basin site. With respect to the Dofasco boatslip, the first two nitrate injection treatments on July 28 were only 20% as efficient and the second set of treatments on Sept. 15-17 were about 50% as efficient as treatments at other sites.

The nitrate injection resulted in a rapid (within two weeks) increase of redox of about 100 mV units. The addition of nitrate results in the oxidation of reduced sulphur to sulphate.

1993 Profiles

The time sequence of sampling of the St. Marys River and Hamilton Harbour again illustrates that the nitrate falls through the sediments. For example, shortly after treatment of the Dofasco Boatslip the sulphate produced by the treatment was found near the subsurface but months later, the sulphate was about 30 cm deeper. In Hamilton Harbour, the sediments are enriched with metals (Table 11) , but the metals do not interfere with the biodegradation of the organic contaminants.

Sediment dialysis experiments were conducted after sediment treatment with nitrate in the deep basin of Hamilton Harbour. The oxidation of the sediments decreased the iron concentration of the porewater from 50 mg/L to 1 mg/1 in the top 15 cm of sediments. The iron precipitation results in significant precipitation of barium, cadmium, cobalt, chromium, copper, lithium and nickel. The concentrations of manganese, lead and zinc were unchanged (Table 14) . Stontium increased in the treated porewater, but it appears to be an innocuous, impurity in the calcium nitrate. The precipitation of iron resulted in precipitation of phosphorus from about 1.5 mg/L to 0.5 mg/L. The precipitation of phosphorus would be beneficial in treatment of lakes for eutrophication, but in some sites it might slow microbial biodegradation.

The in situ diffusion chamber (peepers) studies of 1992 in Hamilton Harbour were continued with laboratory dialysis studies. With sediments from Embayment A, Toronto, nitrate treatment resulted in the precipitation of iron in the porewater from 30 mg/L to 1 mg/L. There was no significant change in the concentration of lead or other trace metals. Metals at this site do not appear to limit the bioremediation. Metals are not dissolved by sulphide oxidation. Table 14

PORE WATER ANALYSIS

Hamilton Harbour Deep Basin Sediment Injection Site

October 20, 1992

CO Treated Sediments (Average ol top 15 1 cm sediment samples) c

CD Al lot Ba-tot Bθ-tot Cd-tol Co-tot Cr-tot Cu-tot Fe-tot u-tot- Mn-tot Mo-tot Ni-tot Pb-tot Sr-tot V-tot Zπ-tot

CO (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) H

H AVERAGE 0.04 0.06 0.00 0.00 0.00 0.00 0.00 10.53 0.01 5.86 0.00 0.01 0.04 0.61 0.00 0.02

C STD. DEV. 0.00 0.04 0.00 0.00 0.00 0.00 0.00 14.98 0.00 6.33 0.00 0.01 0.03 0.36 0.00 0.01 H m

CO Control Sediments (Average ol lop 15 1 cm sediment samples)

X m AVERAGE <.04 0.166 <1 0.009 0.003 0.007 0.004 40.296 0.006 6.301 0.002 0.004 0.005 0.443 0.004 0.018

STD. DEV. 0 0.051 0 0.003 0.001 0.001 0.000 17.138 0.001 2.106 0.001 0.000 0.002 0.045 0.001 0.003

The in place treatments in 1992 resulted in excellent biodegradation of several organic compounds (mean of three samples, reductions as follows; toluene 80%, ethylbenzene 86%, m/p-xylene 76%, 3/4-ethyltoluene 89%, and dichloromethane 65%) (Fig. 29) .

In 1992, analysis of three samples indicates that 25% of the petroleum hydrocarbons were biodegraded in the Dofasco boatslip treatment. About 40% of the oil and grease biodegraded in the 1992 treatment neat Stelco. By the end of 1993 about 57% of the TPH biodegraded in the Dofasco Boatslip (Fig. 39) .

The biodegradation of the PAHs (polynuclear aromatic hydrocarbons) is more complex. In 1992, about 15% (450 μg/g to 383 μg/g,mean of 3 samples) of 15 PAHs were biodegraded and in the process the naphthalene content increased 196% (280 μg/g to 549 μg/g) , mean of 3 samples (Fig. 41) . The imbalance in the concentration of naphthalene suggests that other higher molecular weight compounds not measured in the standard priority pollutant PAH analysis are decomposing to produce naphthalene. Approximately 50% of the PAHs in coal tar pitch contain more than seven rings; we are capable of measuring leas than 50% of the PAHs.

Two field treatments were conducted in the Dofasco Boatslip, once with calcium nitrate (6 tonnes) and once with calcium nitrate and yeast (13 tonnes) . The high concentrations of naphthalene observed in 1992 were biodegraded (Fig. 42) . The naphthalene concentration in the fall of 1993 was 40 μg/g (280 μg/g in spring of 1992, 549 μg/g in fall of 1992) . The coefficient of variation of the total PAHs was high (43) , in part because the treatment of the east slope was less effective. The flat area was treated better (as shown by nitrate data) and hence the PAH concentration was reduced by 49% (from initial) .

In April of 1994, the concentration of 15 PAHs (not naphthalene) had decreased to 200 μg/g (Fig. 14, mean of 5 samples, 48% of initial) . This decrease of PAHs was much more rapid than observed in earlier treatments. In spite of the winter temperatures which can inhibit some bacteria, the yeast amendment stimulated biodegradation.

The iron treatment in 1991 has resulted in a greater bio ass of macrophytes. In September 1993, in the control area, Elodea was less than 0.6 m tall while in the iron treated area they were >1.5 m tall. The decrease in organic contamination is confounded by the general recovery of the sediments in this part of the bay. When we started, the oil and grease concentration exceeded 2%; now it is about 0.2%. The sediment contamination here is shallow (<15 cm) .

The sediment treatments with nitrate in 1992 were not as successful as the iron treatment. This treatment was done further to the east where the sediment contamination is deeper. At first we did not realize the depth of contamination and we thought it would be possible to produce a surface cap of bioremediated sediments. This is similar to the common idea of letting clean freshly weathered material deposit a cap over contaminated sediments. We discovered in Hamilton Harbour that diffusion of substances in porewater is much faster then anticipated. The surface 20-25 cm of sediment equilibrates within 4-6 weeks. The treatments were designed to treat the top 10 cm (1992) and top 25 cm (1993) of sediment, but in the 1992/93 sites in the St. Marys River, the contamination is >250 cm deep.

Sediment Compaction/Consolidation Results

The lack of sediment resuspension is partly caused by the flocculation of colloids by the added calcium. No significant difference between the concentration of suspended solids in the water column was measured upstream and downstream of the site on the St. Marys River (Table 15) . In the laboratory, agitated sediments that were pretreated with calcium nitrate settle within several minutes but agitated untreated sediments stay turbid for hours. Also, the water content of the sediments collected at two treated sites near Stelco in Hamilton Harbour was reduced by 16%. This reduction in water content was presumably achieved by flocculation of colloids resulting in less separation of the particles.

The compaction of the sediments in the St. Marys River sediments was more dramatic than in Hamilton Harbour, in part because the clear riverwater allowed us to see the 25 cm collapse of the sediments after treatment. This collapse was only partly a reflection of flocculation reactions. There was a large release of gas from the sediments during the injection. To verify that the collapse was caused largely by gas release, we sampled gas in treated and untreated sediments (mean of 77+9 and 120+43 liters/m², respectively) . The differences between control and treated areas was compromised by the diver mediated collection of the gas; his actions released gases from deeper untreated sediments. At this site, the contaminated sediments are more than 2.5 m deep; the sediment injection equipment penetrated about 25 cm. The drop of sediment height corresponds to a 50% compaction.

Table 15

Summary of Sediment Trap Data-St. Marys River Chemical

Treatments

July 8, 1991 Oct. 10, 1991

Upstream Downstream Upstream Downstream

0.122 0.182 0.066 0.049

0.140 0.169 0.064 0.029

0.154 0.144 0.047 0.074

0.081 0.158 0.048 0.081

0.124 0.163 Average 0.056 0.058

Data in grams of dry sediment. No significant differences between upstream and downstream.

The composition of sediments of 16%-50% by in situ treatment would represent a significant increase in the efficiency of a clamshell dredge. More mud would be removed in each cycle of the dredge and less water would have to be removed from the dredged sediments prior to transportation and storage.

The release of methane gas is also important to the bioremediation. Figure 43 illustrates methane oxidant demand at the St. Marys River site. Initial efforts at bioremediation were unsuccessful at this site because of the flux of methane from these deep sediments (2.5 m depth used for calculation) .

GENERAL CONCLUSIONS

^"Biodegradation of TPHs and PAHs was relatively fast in reactor experiments from sediments from five series. At four of these sites an organic amendment increased microbial metabolic activity by 5-10 fold. The requirement for the organic amendment appears related to the inactivation of phosphorus by calcium. For treatment of eutrophic lakes, calcium nitrate without an organic nutrient amendment should be highly effective, albeit some sites might require additional amendments like lime or iron. For in situ treatment of biodegradation of organic contaminants like oil and coal tar,yeast amendment with nitrate is the preferred treatment. Waste brewers yeast is inexpensive, especially compared to the cost of culturing a special strain of bacteria (or fungus) .

Claims

WE CLAIM :

1. A method of effecting natural microbial biodegradation of polynuclear aromatic hydrocarbons and petroleum hydrocarbons in sediment containing microbes and polynuclear aromatic hydrocarbons and petroleum hydrocarbons, characterized in that the method comprises the steps of: providing a biochemical oxidant for detoxifying a microbial toxin produced during microbial biodegradation of said polynuclear aromatic hydrocarbons and petroleum hydrocarbons; contacting said sediment with said oxidant to detoxify said toxin; and effecting microbial biodegradation of said polynuclear aromatic hydrocarbons and petroleum hydrocarbons.

2. The method as defined in claim 1, characterized in that the contacting step is a reaction step.

3. The method as defined in claim 1, characterized in that said oxidant comprises an alkaline earth nitrate.

4. The method as defined in claim 1, characterized in that said alkaline earth nitrate comprises calcium nitrate.

5. The method as defined in claim 1, further including the step of nutrifying said microbes with nutrients.

6. The method as defined in claim 1, characterized in that said method is a continuous method.

7. The method as defined in claim 1, characterized in that the step of contacting said sediment with said oxidant to detoxify said toxin includes contacting said sediment in a first contacting step with said oxidant at a first level therein.

8. The method as defined in claim 7, characterized in that said step further includes the step of contacting said sediment in a second contacting step with said oxidant at least at a second level in said sediment, said second level being different from said first level and effecting said natural microbial biodegradation of said polynuclear aromatic hydrocarbons and petroleum hydrocarbons.

9. An apparatus suitable for treating sediment in a water body, said sediment containing chemical pollutants, characterized in that said apparatus comprises: a first dispensing means adapted for dispensing a treatment compound into contact with said sediment to be treated at a first level; a second dispensing means adapted for dispensing said treatment compound within said sediment at a second level; each of said dispensing means having means for connection with a supply of said treatment compound; and support means for supporting said first dispensing means and said second dispensing means.

10. The apparatus as claimed in claim 9, characterized in that said apparatus further includes mounting means for mounting said apparatus to a carrier vessel.

11. The apparatus as claimed in claim 10, characterized in that said apparatus further includes a carrier vessel for receiving said mounting means.

12. The apparatus as claimed in claim 11, characterized in that said carrier vessel includes a rotatable platform for permitting rotation of said apparatus.

13. The apparatus as claimed in claim 9, characterized in that said first dispensing means comprises a plurality of connected spray bars for spraying said treatment into said sediment.

14. The apparatus as claimed in claim 13, characterized in that said second dispensing means includes a plurality of finger means for supporting said second dispensing means.

15. The apparatus as claimed in claim 14, characterized in that said finger means comprise arcuately shaped members for penetrating said sediment.

16. The apparatus as claimed in claim 15, characterized in that said dispensing means comprises nozzles.

17. A method of effecting compaction of sediment containing microbes, polynuclear aromatic hydrocarbons and petroleum hydrocarbons, characterized in that said method comprises the steps of: providing a biochemical oxidant for detoxifying a microbial toxin produced during microbial degradation of said polynuclear aromatic hydrocarbons and petroleum hydrocarbons; providing a fermentation by-product organic amendment; contacting said sediment with said oxidant and said fungal organic amendment; effecting microbial degradation of said polynuclear aromatic hydrocarbons and petroleum hydrocarbons; and compacting said sediment by evolution of gaseous by¬ products evolved from contact of said oxidant and amendment with said sediment.

18. The method as defined in claim 17, characterized in that said fermentation by-product amendment comprises a fungal organic amendment.

19. The method as defined in claim 17, characterized in that contact of said sediment with said oxidant is an oxidation step.

20. The method as defined in claim 17, characterized in that said oxidant comprises an alkali earth nitrate.

21. The method as defined in claim 20, characterized in that said alkali earth nitrate comprises calcium nitrate.

22. The method as defined in claim 20, characterized in that said fungal organic amendment comprises yeast.

23. The method as defined in claim 22, characterized in that said yeast is a viable yeast culture.

24. The method as defined in claim 22, characterized in that said yeast is a non-viable yeast culture.

25. The method as defined in claim 22, characterized in that said yeast comprises brewers yeast.

26. The method as defined in claim 25, characterized in that said yeast has a moisture content.

27. The method as defined in claim 17, characterized in that said gaseous by-products at least include methane.

28. A method of effecting natural microbial biodegradation of polynuclear aromatic hydrocarbons and petroleum hydrocarbons in sediment containing microbes and polynuclear aromatic hydrocarbons and petroleum hydrocarbons, characterized in that said method comprises the steps of: providing a biochemical oxidant for detoxifying a microbial toxin produced during microbial biodegradation of said polynuclear aromatic hydrocarbon and petroleum hydrocarbons; providing a fermentation byproduct organic amendment; contacting said sediment with said oxidant and said organic amendment; and effecting microbial degradation of said polynuclear aromatic hydrocarbons and petroleum hydrocarbons.

29. The method as defined in claim 28, characterized in that said organic amendment comprises a fungal organic amendment.

30. The method as defined in claim 2₉, characterized in that said fungal organic amendment comprises yeast.

31. The method as defined in claim ₃₀, characterized said yeast is a viable yeast culture.

32. The method as defined in claim 28, characterized said biochemical oxidant comprises an alkali earth nitrate.