1 Use of ochre from an abandoned metal mine in the south east of Ireland for
2 phosphorus sequestration from dairy dirty water.
3
4 O. Fenton
1
, M.G. Healy
2
, and M. Rodgers
2
5
6
1
Teagasc, Johnstown Castle, Environmental Research Centre, Co Wexford, Rep. of
7 Ireland
8 E-mail: owen.fenton@teagasc.ie
9
2
Dept. of Civil Engineering, National University of Ireland, Galway, Rep. of Ireland
10
11 Abstract
12
13 Ochre found at coal mine drainage sites in the U.K. shows a high P retention capacity,
14 with little mobilisation of metals. This indicates that ochre has the potential to adsorb
15 phosphorus (P) from agricultural wastewaters for possible use as a fertiliser. To date,
16 little research has focused on the ability of metal mine ochre to sequester P in an
17 environmentally sustainable way. Untreated acid mine drainage (AMD) from an
18 abandoned copper- sulphur (Cu-S) mine in the Avoca-Avonmore catchment in the
19 south east of Ireland results in extensive low-value ochre deposition. In this study, P-
20 amended water (50 ml) was mixed with this ochre (2.5 g) in batch experiments and a
21 maximum P adsorption capacity, calculated from the Langmuir equation, of between
22 16 and 21 g P kg
-1
was calculated. However, mobilisation of heavy metals from Avoca
23 ochre in distilled, surface and dirty water batch experiments was observed. This
1

24 mobilisation may inhibit the ochre’s use in P removal from wastewaters.
25
26 Keywords: dirty water; acid mine drainage; ochre; phosphorus; dissolution.
27
28 1. Introduction
29
30 The EU Water Framework Directive (WFD), 2000/60/EC (EC, 2000), aims to achieve
31
‘at least’ good status of all waterbodies by 2015. It requires each member state to
32 address deficiencies in existing controls governing: wastewater and industrial
33 discharges; landfills, quarries, mines and contaminated lands; wastewater from un-
34 sewered properties; forestry; usage and discharge of dangerous substances; and
35 agriculture. In Ireland, the agricultural sector is governed by the Good Agricultural
36 Practice for the Protection of Water Regulations 2006 (S.I. No. 378 of 2006). These
37 Regulations divide Ireland into three zones. Each zone has different rules about the
38 storage capacity of organic fertiliser, as well as specified dates where the
39 landspreading of organic and chemical fertiliser is prohibited.
40
41 Dirty water is generated from dairy parlour water and machine washings, precipitation
42 and water from concreted holding yards. Much research is now focused on remediation
43 of dirty water (Fenton et al., 2008). Using a material with a high phosphorus (P)
44 adsorption capacity, P could be sequestered from dirty water and made available for
45 farm uses. In their review of remediation and control systems for agricultural
46 wastewater in Ireland, Fenton et al. (2008) identified ochre as a potential material.
2

47 However, to date, the use of ochre for this purpose has not been extensively examined
48 (Dobbie et al., 2005).
49
50 Ochre has site-specific physical and chemical characteristics, which are dependent on:
51 iron (Fe) mineralogy, water content of sediments, degree and rate of oxidation, age of
52 deposits, pH, Fe supply, and concentrations of alkali and sulphate (SO
4
) associated
53 cations (Singh et al., 1999). Saturated ochre from two mine water treatment plants
54 (MWTPs) in the UK - Polkemmet, West Lothian and Minto, Central Scotland - showed
55 maximum P retention capacities of 26 g P kg
-1
and 30.5 g kg
-1
, respectively (Bozika,
56 2001; Heal et al., 2003). Comparatively, Heal et al. (2003) gave maximum P
57 absorbencies of other materials: Danish sands, 0.02-0.13 g kg
-1
; blast furnace slag,
58 0.05-0.65 g kg
-1
; steel furnace slag, 1.4 g kg
-1
; zeolite, 2.2 g kg
-1
, laterite, 0.75 g kg
-1
;
59 lagoon fly ash, 3.1 g kg
-1
; iron oxide tailings, 8.6 g kg
-1
; and precipitator fly ash, 14 g
60 kg
-1
.
61
62 Dobbie et al. (2005) investigated an end use for P-saturated ochre as a slow release
63 fertilizer. P-saturated ochre was added at four rates – 20, 40, 80 and 200 t ha
-1
– in one
64 application to a soil/sand mixture in 5 L pots planted with either grass or barley. At the
65 end of the 4-month study, on average, 4% of the measured P in ochre was immediately
66 plant-available and no significant difference was noted in soil total aluminium (Al),
67 chromium (Cr), nickel (Ni), or zinc (Zn) between the treatments. Soil Fe and
68 manganese (Mn) increased as the ochre additions to the soil increased, but all metals –
69 with the exception of Ni, which was also high in the study control – were within
3

70 guideline limits.
71
72 The ability of ochre to adsorb P can be assessed using Freundlich and Langmuir
73 isotherms (Poots et al., 1976; Froelich, 1988); the Langmuir model can be used to
74 provide an estimate of the maximum mass of P adsorbed per mass of the ochre
75 (Sharpley, 2000). One form of the Langmuir isotherm equation is (McBride, 2000):
76
77
C e x m

1 ab

C e b
(1)
78
79 where C e
is the concentration of P in solution at equilibrium (mg L
-1
), x/m is the mass
80 of P adsorbed per unit mass of ochre (g kg
-1
) at C e
, a is a constant related to the
81 binding strength of molecules onto the ochre, and b is the theoretical amount of P
82 adsorbed to form a complete monolayer on the surface, thus providing an estimate of
83 the maximum adsorption capacity of the ochre (g kg
-1
). A more accurate maximum
84 adsorption capacity may be achieved by saturation experiments (Arias et al., 2001).
85
86 In the Avoca–Avonmore river catchment, Co. Wicklow, in the south east of Ireland,
87 untreated acid mine drainage (AMD) from an abandoned Cu-S mine discharges to the
88 Avoca River, resulting in ochre deposition and pronounced metal contamination of the
89 receiving waters (Toner et al., 2005). If remediation is carried out in the Avoca-
90 Avonmore catchment, large quantities of low-value ochre will require regulated
91 disposal unless alternative uses can be found. This paper aims to establish if the ochre
4

92 is suitable for sustainable use as a P adsorbent by: (1) characterising the ochre from
93 this catchment; (2) estimating its maximum P adsorption capacity using P-amended
94 water and dairy dirty water; and (3) measuring the mobilisation of metals from the
95 ochre through agitation in distilled water.
96
97 2. Materials and Methods
98
99 2.1 Site description
100
101 The Cu-S drainage adit site is located at White Bridge, Avoca. Ochre is deposited for
102 approximately 300 m along a tributary that leads to the Avoca River (Figure1).
103 Sulphide minerals, such as pyrite, chalcopyrite, sphalerite and galena, are present on
104 site. The sulphide mineral deposits, classified as volcanogenic massive sulphide, were
105 hosted in the local Ordovician volcanic rocks.
106
107 Ochre settling pits were used during the mining processes of the 1940s (Gallagher and
108
O’Connor, 1999). Upstream of the confluence of the Cu-S adit tributary and the Avoca
109 River, Yau and Gray (2005) measured Zn, Cu, Fe and Pb concentrations in the Avoca
110 River sediments of 336±34 μg Zn L
-1 , 221±101 μg Cu L -1 , 5.39±0.17 Fe μg L -1
, and
111
334±21 μg Pb L -1
(Figure 1). Downstream of the confluence, these sediment
112 concentrations were 5640±329 μg Zn L
-1 , 455±22 μg Cu L -1 , 8.08±0.23 μg Fe L -1
, and
113
500±194 μg Pb L -1
, indicating a contamination source input to the main river between
114 these two sampling points (Figure 1).
115
5

116 2.2 Sample collection and ochre physical parameters
117
118 In Spring 2007, 81.5 mm-diameter and 60 mm-deep ochre cores were collected from
119 ochre beds and from the adjacent forest floor. The forest floor samples were present
120 due to flooding events in the lower reaches of the Avoca–Avonmore catchment. The
121 ochre was examined for dry bulk density and particle density (after Blake and Hartge,
122 1986), total porosity (after Brady and Weil, 1996), aggregate stability (wet sieving
123 method, BS 1377), undisturbed saturated hydraulic conductivity ( K s
) (falling head
124 method, BS 1377), particle size distribution (sieving and pipette method, BS 1796).
125 Ochre from the forest floor was analysed for total metals, nutrients, mineralogy and
126 was used in all batch experiments. Tributary stream water was also collected and
127 analysed for total metals, nutrients, sulphate (SO
4
-), pH and redox potential (Eh).
128 Stream sediment was also analysed for metals. Water samples were filtered through a
129
0.45 μm filter membrane. The nutrients were determined using a Thermo Konelab 20
130 analyser (Technical Laboratory Services, Ontario, Canada) and the metal content was
131 determined using an ICP VISTA-MPX (Varian, California). Total metal determination
132 of ochre sediment and tributary surface water samples were measured by aqua regia
133 digestion using a Gerhard Block digestion system (Cottenie and Kiekens, 1984). To
134 analyse the metals, a 2 g sample of dry sediment material was loaded into a Gerhardt
135 reflux tube and 5 ml of deionised water was added to make up a slurry. Then, 16 ml of
136 aqua regia was added (4 ml of hydrogen nitrate (HNO
3
) + 12 ml of hydrochloric acid
137 (HCl)). The samples were left to stand overnight and then were placed on a Gerhard
138 reflux system for 2 hr (40 ºC and left to cool). A 100 ml volume sample was made up
6

139 with 2 ml HNO
3
. The solution was then filtered and analysed for Cu, Zn, Mn, Fe, Ni,
140 Cr, cadmium (Cd), arsenic (As), Pb, P, magnesium (Mg), sodium (Na), and potassium
141 (K) using the ICP VISTA-MPX. For quality control, two reference soil samples, of
142 known metal concentration, from the Wageningen International Soil-Exchange
143 Program, were analysed.
144
145 2.3 Batch experiments
146
147 All the batch experiments were conducted with ochre from the ochre beds.
148
149 3.2.1 P-amended water
150
151 In preparation for the P adsorption isotherm tests, the forest floor ochre was air dried,
152 ground, and sieved to less than 2 mm. P solutions were made up using dissolved
153 potassium phosphate (KH
2
PO
4
) in distilled water (pH 6.9). In a set of 104 tests using
154 graduated capped tubes, 2.5 g samples of washed ochre were overlain with 50 ml of
155 PO
4
-P solutions ranging in concentration from 24.3 mg PO
4
-P L
-1
to 1137 mg PO
4
-P L
-
156
1
. These samples were not shaken. After 24 hrs, the supernatant was extracted,
157 centrifuged for 15 mins, filtered through a 0.45 μm filter membrane and analysed for P
158 on the Thermo Konelab 20 analyser. This experiment was repeated with another set of
159 104 ochre samples that were shaken for 24 hours using an end-over-end shaker.
160
161 2.3.2 Dirty water
7

162
163 During July and August, 2007, 55 dirty water samples were collected from a 120-cow
164 dairy farm (Teagasc, Johnstown Castle, Wexford) and analysed for Cl, PO
4
-P, total P
165 (TP), total nitrogen (TN), total oxidized nitrogen (TON), ammonium-N (NH
4
–N) and
166 nitrite-N (NO
2
-N). Four random samples of dirty water were collected from the dairy
167 yard storage tank and 198 shaken and unshaken experiments were repeated using 2.5 g
168 of ochre overlain with dirty water (50 ml) at three dilutions: 1:20, 1:10 and 1:5. After
169 24 hrs, the supernatant was analysed for TP.
170
171 2.4 Ochre saturation and desorption
172
173 For the evaluation of the saturation capacity of the ochre, 5 g samples of forest floor
174 ochre, which were air dried and sieved to less than 2 mm, were placed in five sintered
175 glass funnels and overlain with P-amended water of known concentration (100 mg L
-1
)
176 and volume (100 ml).
The supernatant water was allowed to filter through the ochre
177 sample into a collection flask. Each day, when drainage was complete, a sub-sample of
178 10 ml was collected from the flask and analysed for PO
4
-P. This experiment was
179 repeated until the influent and drainage waters had the same PO
4
-P concentration i.e.
180 until ochre saturation had occurred. This procedure was repeated using dirty water.
181 Desorption of adsorbed P was carried out by taking a 2.5 g sample of the saturated
182 ochre from the sintered funnel experiment. This was shaken with 50 ml of distilled
183 water in an end-over-end shaker for 24 hrs. At the end of this experiment, the
184 supernatant was centrifuged and analysed for PO
4
-P.
8

185
186 2.5 Kinetic experiments
187
188 Four P solutions with concentrations of 26.4, 52.3, 108.7 and 188.5 mg PO
4
-P L
-1
were
189 prepared. Volumes (50 ml) of each solution were poured into 6 graduated tubes with
190 2.5 g of forest floor ochre – 24 tubes in all. The tubes were shaken in an end-over-end
191 shaker and the supernatant water was sampled, centrifuged, filtered and analysed for
192 PO
4
-P after 1, 5, 14, 30, 60 and 120 mins.
193
194 2.6 Ochre mobilisation
195
196 The mobilisation of heavy metals from ochre into solution was examined by
197 overlaying 5 g of forest floor ochre, which was air dried and sieved to less than 2 mm
198 size, with distilled water, surface lake water and dirty water. The experiment was
199 replicated 5 times for both shaken and unshaken samples. After 24 hours, the
200 supernatant was analysed for trace metals.
201
202 2.7 X-ray diffraction analysis of Avoca ochre
203
204 An oven-dried sample and an air-dried sample of forest floor Avoca ochre were
205 compared using XRD analysis. The dry sample was prepared as a standard bulk XRD
206
207 specimen in a side fill holder. The specimen was examined using the Siemens D5000
Diffractometer D6 with Cu K

radiation, a variable divergence of 12 mm, primary
9

208 sollers, 0.2 mm receiving slit, and an energy-dispersive detector. The following
209 standard operation practices were used to examine the specimen: SOP/XRD/8 V3
210 standard procedure for specimen preparation for XRD; SOP/XRD/64 V1 general
211 method for data collection on the Siemens D5000 diffractometer D6 using Bruker
212 AXS Diffrac and Basic Measurement Centre XRD Commander 2.4 Software; and
213 SOP/XRD54 V5 general method for phase identification using a Bruker AXS Diffrac
214 and “EVA” XRD evaluation software.
215
216
217 3. Results
218
219 3.1 Ochre physical and chemical parameters
220
221 Physical soil parameters for the in situ Avoca ochre from the ochre beds are presented
222 in Table 1. The ochre is fine-grained with the following constituency: coarse sand
223 (21.6 % by mass), fine sand (19.5 % by mass), silt (22.3 % by mass), and clay (30.9%
224 by mass). The particle density of the ochre is low at 2.30 g mL
-1
, which facilitates
225 entrainment and transportation in overland flow during flood events. Avoca ochre has
226 some similar physical characteristics to other ochre found at coal mine sites (Table 2).
227
228 The forest floor ochre collected from Avoca showed higher concentrations of
229 potentially toxic elements such as Pb, Cu and As in comparison with ochre from the
230 Polkemmet site in the UK (Table 3). Background concentrations and quality objectives
10

231 for heavy metals in surface sediments (including ochre) of freshwater ecosystems in
232 the Avoca Avonmore catchment are: Pb, 22 mg kg
-1
and Cu, 23mg kg
-1
(Yau et al.,
233 2005). These concentrations are considerably higher than the maximum allowable
234 concentrations for contaminated land (86/278/EEC; EEC, 1986). Therefore, Avoca
235 ochre would not be suitable for land application after P saturation.
236
237 Metal concentrations in the tributary ochre sediment were: Cu, 23 mg kg
-1
; Fe, 44 g kg
-
238
1
; Pb, 22 mg kg
-1
; and Zn, 69 mg kg
-1 indicating increased metal accumulation in ochre
239 sediment outside the tributary. The elevated metal concentrations in the Avoca River
240 downstream from the adit are directly related to the AMD, as documented by Yau and
241 Gray (2005). In this earlier study, the tributary water had a pH range of 4-6 and a
242 positive Eh (450 mV) indicating an oxidising environment. This may yield a rapid
243 precipitation of Fe through oxidation and hydrolysis reactions. During this study the
244 pH of the AMD ranged from 2.9±0.6 (SO
4
-
- 1108 mg L
-1
) at the drainage adit to
245
4.8±0.6 (SO
4
-
- 22 mg L
-1
) upon entering the main river. Redox potential ranged from
246
415±1.7 mV to 100±4 mV at the same locations.
247
248 3.2 P-amended and dirty water batch experiments
249
250 The adsorption experiments showed that shaking in the end-over-end shaker improved
251 the P adsorption capacity of the P-amended water when high initial PO
4
-P
252 concentrations were used. For an initial PO
4
-P concentration of, say, 200 mg L
-1 in
253 solution, approximately 4 g kg
-1
is adsorbed – 39% more than an unshaken sample at
254 the same initial concentration (Figure 2a). However, this difference was less
11

255 pronounced at lower initial PO
4
-P concentrations e.g., at an initial PO
4
-P concentration
256 of 25 mg L
-1
, 0.50 g kg
-1
and 0.43 g kg
-1
were adsorbed for shaken and unshaken batch
257 experiments, respectively. There appeared to be no significant difference between the
258 TP concentrations when the experiment was repeated with shaken and unshaken dirty
259 water samples (Figure 2b). This suggests that shaking may only be necessary in P-
260 amended and dirty water when the initial P concentration is high.
261
262 Using a Langmuir isotherm, it was estimated that ochre had a maximum adsorption
263 capacity of approximately 21 g PO
4
-P kg
-1
when mixed with P-amended distilled water
264 (Figure 3). It was not possible to fit a Langmuir isotherm for the dirty water samples as
265 almost all the P was adsorbed by the ochre within the study period. Since the dairy
266 farm produced approximately 9500 L of dirty water daily with a mean TP
267 concentration of 20.1 mg L
-1
(Table 4), it would have taken approximately 9 kg of
268 ochre to sequester all the P in the daily dirty water, based on the Langmuir isotherm
269 maximum adsorption capacity of the synthetic P solutions.
270
271 Ochre in the sintered funnel experiments reached a mean saturation concentration of
272 16.3±2.3 g PO
4
-P kg
-1
. This compares well with the maximum P-retention capacity of
273 21 g PO
4
-P kg
-1
estimated by the Langmuir isotherm. Desorption experiments showed
274 < 1% of PO
4
-P was released from the ochre within 24 hrs. Using the saturated range
275 for P retention capacity 10-12 kg of ochre would be needed to sequester the daily dirty
276 water on the farm.
277
278 3.3 Kinetic experiments
12

279
280 P removal by Avoca ochre is rapid. Within 5 minutes of shaking, the supernatant PO
4
-P
281 concentration decreased by in excess of 97% (Figure 4). This was due to the ochre
282 chemical composition and the large surface area available for P adsorption associated
283 with Avoca ochre mineralogy.
284
285 3.4 Ochre metal mobilisation
286
287 Mobilisation of trace metals during batch experiments was evident in all tests and
288 agitation increased mobilisation (Table 5). The increase in concentration of all metal
289 parameters followed the same trend as the results of Yau and Gray (2005), who found
290 that mobilised metal concentration increased following mixing of the Cu-S adit
291 tributary with the Avoca River. Zn had the highest % increase – greater than 99% in all
292 cases - after mixing with distilled water, dirty water and surface water; this increase
293 was of the same order as the increase measured by Yau and Gray (2005). Of the
294 parameters tested, all the parameters regulated by the EU Directive 75/440/EEC (EEC,
295 1975) governing waters intended for the abstraction of drinking water – Fe, Cu, Mg
296 and Zn – were above the mandatory concentrations allowable (Table 5). Kinetic tests
297 indicated that most of the metal mobilisation occurred within 1 minute of mixing P
298 solutions with the ochre.
299
300 3.5 X-ray diffraction
301
13

302 Results from XRD analysis showed no apparent phase changes on drying. The X-ray
303 scatter from the water was reduced and lower intensity peaks became more apparent.
304 The ochre contained amorphous material and the pattern was complex with multiple
305 and overlapping peaks of varying widths. The X-ray diffraction pattern was dominated
306 by common soil minerals characteristic of the AMD site: quartz, albite and nimite.
307 Trace phases of clay type minerals were tentatively identified: clinochlore (Mg-rich
308 chlorite) type shown by the ICDD reference diffraction pattern of (Mg, Al,
309 Fe)
6
(SiAl)
4
O
10
(OH)
8
and muscovite-type, shown by the ICDD reference pattern for
310 KAl
2
.9Si
3
.1O
10
(OH)
2
.
311
312 Fe mineralogy includes well crystallised goethite, jarosite and hydronium jarosite.
313 Also present were lepidicrocite and ferrihydrite. Ferrihydrite was present in the form of
314 nano-crystalline material. Goethite and Ferrihydrite dominated the sediment. Goethite
315 crystalline size ranged from 8-10 nm in all samples. Ferrihydrite crystalline size ranged
316 from 3-6 nm.
317
318 4. Discussion
319
320 The P adsorption capacity of Avoca ochre was comparable with ochre tested in the UK
321 but its characteristics are site-specific (Fenton et al., 2007). High adsorption capacity
322 due to Fe mineralogy, combined with slow release once saturated, suggests ochre may
323 be used in the treatment of water to sequester P from solution. Fe minerals, such as
324 goethite, jarosite, hydronium jarosite, lepidicrocite and ferrihydrite, were found in the
14

325 Avoca ochre, and P may adsorb to their surfaces. P adsorption to goethite involves
326 rapid ligand exchange with surface hydroxide (OH
-
) groups at reactive sites and the
327 formation of a binuclear-bridging complex between a phosphate group and two surface
328 Fe atoms. This is followed by a weaker ligand exchange. Very little desorption occurs.
329
330 The in situ K s
is sufficient to indicate that ochre could be used in P sorption filters but
331 experiments should be carried out to make sure that the P sorption process does not
332 induce clogging. However, the high concentration of metals found in the Avoca ochre
333 and high levels of mobilisation in distilled, surface and dirty water may limit its use in
334 P sequestration technologies. Even without agitation, the mobilised metals exceeded
335 EU limit concentrations.
336
337 5 Conclusions
338
339 The following conclusions can be drawn from this study:
340 a. Batch experiments showed that ochre had a maximum estimated sorption capacity of
341 16 to 21 g PO
4
-P kg
-1
.
342 b. In the shaken batch experiments, the ochre adsorbed up to 97% of the P in the first 5
343 minutes of the experiment.
344 c. Mobilisation of heavy metals occurred in distilled, surface and dirty water samples
345 using ochre from a metal mine source. This may hinder its use in P sequestration
346 technologies.
347 d. The use of ochre from metal mine origin as a P sequestration amendment in
15

363
364
365
366
367
368
369
370
348 conjunction with another environmental technology (e.g. wetland) should be
349 examined.
350
351 Acknowledgements
352
353 The authors would like to thank Prof. Nicolas Gray, Trinity College Dublin; Con
354 Dowdal, Denis Brennan, Maria Radford and Nicola Rochford, Teagasc, Johnstown
355 Castle, for assistance during the project.
356
357
358
359
360
361
362
16

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453
454 Toner, P., Bowman, J., Clabby, K., Lucey, J., McGarrigle, M., Concannon, C.,
455 Clenaghan, C., Cunningham, P., Delaney, J., O’Boyle, S., MacGarthaigh, M., Craig,
456 M., Quinn, R. 2005. Water quality in Ireland. Environmental Protection Agency, Co.
457 Wexford, Ireland.
458
459 Yau, H., Gray, N.F. 2005. Riverine sediment metal concentrations of the Avoca –
460 Avonmore Catchment, South East, Ireland: A baseline assessment. Biology and
461 Environment: Proceedings of the Royal Irish Academy ,105B, 95 – 106.
462
20

463 Table 1. Selected Avoca ochre parameters from three sampling locations – riverine
464 deposits, ochre beds and adjacent forest floor.
474
475
476
477
478
479
480
481
Mean
Std. deviation
Particle density Total porosity Air filled pores Moisture content MWD g mL -1 % % % mm *
2.30
0.53
82.70
7.63
65.70
7.22
465 *Aggregate stability: wet sieving method - Mean Weight Diameter
466
467
67.20
2.48
0.71
0.02
468
469
470
471
472
473
21

496
497
498
499
500
501
502
482 Table 2. Comparison of physical parameters from a Cu-S mine (Avoca ochre) and two
483 mine water treatment plants in the UK (Polkemmet and Minto).
Parameter Avoca ochre
1
Polkemmet ochre
2
Minto ochre
2
Dry bulk density (g cm
3
)
K s
(m d
-1
)
0.80
0.90-4.80
1.80
26-32
0.80
0.70-1.70
484
485
486
487
1 Obtained from 3 sampling locations at the study site – riverine deposits, ochre beds and adjacent forest floor.
2 Adapted from Bozika (2001).
488
489
490
491
492
493
494
495
22

503 Table 3. Phosphorus and metal concentrations of P saturated forest floor Avoca ochre
504 (Cu-S metal mine origin) and Polkemmet ochre (coal mine origin).
Parameter
Concentration (±std.dev.) in ochre
Polkemmet Limit values 2 Avoca
3 pH 8.7 5-5.5 5.5-6 6-7 g kg
-1
dry wt.
Total phosphorus 16.3(2.3) 22.78(0.12)
Available phosphorus 0.91(0.01) 0.94(0.07)
>7
Aluminium
Iron
4.8(0.04)
246.59(0.02)
10.97(0.38)
271.99(4.76)
Manganese 0.53(0.01) 1.08(0.01) mg kg -1 dry wt.
Arsenic
Cadmium
Chromium
Copper
162.2(18.37)
3.29(0.33)
0.1
<1.5 3
3.19(1.87) 177.5(12.7) 400
80 100 135
Lead
Nickel
2087(75.38)
1.77(0.93)
7.5(1.8)
84.0(7.6)
300
50 60 75 110
Zinc 250.7(19.88) 99.4(1.3)
505
1
After Dobbie et al. (2005).
200 250 300
506
507
2 Sewage sludge directive 86/278/EEC (EEC, 1986). Values indicate maximum permissible concentrations of heavy metals in soils after application of sewage sludge.
508
509
450
23
200

510 Table 4. Mean
(± std. deviation)
dairy dirty water (n=55) nutrient concentrations from
511 July to August 2007.
512
513
TP PO
4
-P TN TON NH
4
-N NO
2
-N mg L
-1
Mean (± std. deviation) 20.1 14.0 170.0 30.4 89.7 18.1
±6.9 ±9.2 ±33.2 ±39.2 ±35.3 ±27.5
24

514
515
516
517
518
Table 5. Average mobilisation (±standard deviation) of metals into solution after 24 hr.
Parameter Units Initial Concentration
Distilled Dirty Water Surface water Distilled water
Cl
Cu
Fe
K
Mg
Mn
Na
Zn mg L ppb ppb mg L -1 122.52 mg L -1 0 ppb mg L -1 ppb
-1 0
0
81.86
1.91
0
26.94
5.72
23.13
26.69
20.96
1.54
57.98
2.87
95.65
41.68(4.38)
0.35(0.89)
220.41(107.11)
3.64(0.91)
8.13(0.40)
Shaken
10.29(0.86)
14,044(290)
1,892(109)
Unshaken
4.80(0.42)
Concentration after 24 hr
Dirty water
Shaken
17.85(0.97)
Surface water Limit 1
Unshaken Shaken Unshaken
10.45(0.65) 55.38(0.88) 45.43(8.24) 200
12.24(4.36) 323.05(30.47) 161.36(18.26) 354.85(37.28) 4.15(0.32)
21.25(1.32) 2.90(0.26) 1.78(0.12) 5.47(0.33) 4.15(0.32)
1.25(10.23)
123(1.60)
1.78(0.22)
6,866(982) 8,358(1,051) 5,059(1,841) 4,580(795) 1,089(1,022)
1,013(294) 1,331(152) 487(45) 608.9(207.6) 86.07(20.92) 300
124.32(1.07) 21.53(5.46)
0.91(0.08) 3.23(0.24)
19.44(2.04)
2.29(0.15)
4.30(0.08)
9.85(0.06)
26.64(0.18)
26.64(0.18)
3.43(0.73)
9.10(0.63)
22.62(3.91)
22.62(3.91)
0.05
18,034(795) 10,132(1,115) 17,016(1,015) 10,159(1,822) 10,560(537) 5,940(1,946) 3000
1 All values tabulated (except Mn and Cl – guide values) represent mandatory values required of surface water intended for the abstraction of drinking water (75/440/EEC,
EEC, 1975).
1

519 Figure 1. The study site location in Avoca, south east Ireland, and Cu-S adit position.
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
1

537 Figure 2. Phosphorus removal in a) P-amended and b) dirty water in shaken and
538 unshaken batch experiments.
539
540
541
542
543
2

544 Figure 3. Langmuir isotherm fitted to actual shaken P-amended water data.
545
546
547
548
549
550
551
552
553
554
555
6000
5000
4000
3000
2000
1000
0
0 shaken
20 y = 48.187x + 60.137
R
2
= 0.9998
40 60
Ce (mg L
-1
)
80 100 120
3

556 Figure 4. Kinetics of phosphorus removal.
557
558
559
560
561
4