MINING EFFLUENT VALORISATION: HOW A PROBLEM BECOMES A VALUE RESOURCE

Estanislao Martínez Martínez CEO AGQ Labs & Technological Services

Manuel José García Gómez CEO AGQ Mining & Bioenergy

MINING

Geological Exploration, Mining and Metallurgy Analytical Characterization

Metallurgical Tests Assays

Environmental Solutions: feasibility, diagnosis, monitoring and rehabilitation studies

BIOENERGY

Biomass production, with an environmental or energetic purposes, employing effluents and/or contaminated lands.

Based on a great knowledge of agronomic process and by application of advance techniques for water and soils treatment, an environmental concern can be solved and also goods production achieve. It can be a biomass fuel production, or a landscaping or an environmental

HUELVA

RIOTINTO MINING AREA BETWEENRIVERS TINTO AND ODIEL

Tarthessus original habitants

Phoenicians

Romans

Visigothic

Moorish

British / French

Spanish

Differents Civilizations involved in Mining Operations since ancients times

Cu and Ag

Pyrite (sulphuric acid)

Pyrite, Cu, Au,…

A HUGE LANSCAPE ALTERATION

ORIGIN OF THE PROBLEM

ACID MINE DRAINAGES

NATURAL ORIGN (RiverTinto)

LIQUIDS WASTE AND EFFLUENTS OF METALLURGICAL PROCESSES

ConcentrationRiver Tinto37º40´21”N 6º32´29”W

River Odiel37º35´45”N 6º50´37”W Units

pH 2.57 2.90 Ud

C.E. 3208 1518 microS/cm

As 0.295 0.005 mg/L

Cd 0.528 0.043 mg/L

Cu 19.12 2.58 mg/L

Fe 324.5 6.3 mg/L

Mn 16.17 119 mg/L

Ni 0.277 0.106 mg/L

Pb 0.078 0.015 mg/L

Zn 21.7 11.3 mg/L

SO4 2118 503 mg/L

Typical River Odiel and River Tinto quality comparison, in the proximity abandoned of mining operations and in the coordinates given

CHEMICAL WATER TREATMENT

ACID MINE DRAINAGE

Neutralization with alkaline hydroxides

Separation of colloids and precipitates

Acidification to pH=6.5

FERTILIZATIONTREATMENT

Ammonium salts

Potassium salts

REAL FERTILIZER SOLUTION

FROM ACID WATERS TO REAL FERTILIZER SOLUTIONS

Treated acid mine waters

Concentration UnitspH 6.50 udC.E. 3150 microS/cmSO4 1440 mg/LCl- 130 mg/LNO3

- 30 mg/LPO4H2

- 70 mg/LCa2+ 440 mg/LMg2+ 122 mg/LNa+ 40 mg/LK+ 0.3 mg/LCu2+ 0.5 mg/LZn2+ 0.8 mg/LB- 0.2 mg/L

TESTING SITE

The research area was located in Burguillos (Sevilla, SW Spain), 37º35´41”N 5º58´55”W.Soils are very calcareous, alkalines (pH: 8 - 8.4), with low organic matter content (<1.5%).

The research plot area was of 1 Ha with a planting density of 3330 plants for Ha.

Each line was equipped with a series of irrigation emitters with a designed flow of 1.6 L/h and spaced 1 m apart (Total irrigation flow of 10.6 m3/h/ Ha).

Eucalyptus globulus and Eucalyptus camaldulensis

* Monitoring and control of crops under technified irrigation

* Optimization of fertilizer solution use and water requirements

* Optimization of the leaching fraction (Minimize environmental impact)

Focus

Controlled Production

Differential

Objective

QUALITY

TECHNIFIED CROPS WITH AN AGRONOMIC CONTROL

SOIL-PLANT-WATER SYSTEM

The roots absorb soluble ions from soil solution

Samples CE pH PO4H2- Cl- SO42- NO3

- NH4+ Ca2+ Mg2+ Na+ K+

mS/cm25ºC (ppm) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L)

Real Fertilizer Solution 3050 6.7 68.1 3.86 28.86 4.86 2.27 21.87 10.45 1.80 1.83

S.Probe at 20 cm 3332 7.6 28.9 4.98 24.52 3.43 0.66 24.33 11.50 2.21 1.08

S.Probe at 40 cm 3550 7.8 17.9 7.20 24.91 2.21 <0.14 25.43 11.25 3.96 0.71

S.Probe at 60 cm 3890 8.2 8.2 10.81 24.98 0.53 <0.14 28.30 11.30 6.28 0.22

Sampling Program Results in May 2010

Samples CE pH PO4H2- Cl- SO42- NO3

- NH4+ Ca2+ Mg2+ Na+ K+

mS/cm25ºC (ppm) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L) (meq/L)

Real Fertilizer Solution 3250 6.4 70.1 3.86 31.22 6.54 3.67 20.45 11.21 1.80 2.25

S.Probe at 20 cm 3112 7.5 38.9 4.78 30.12 4.53 0.45 23.42 10.30 2.11 1.12

S.Probe at 40 cm 3093 7.5 27.9 5.20 29.91 1.75 <0.14 24.56 10.98 2.87 0.54

S.Probe at 60 cm 2920 7.5 0.3 6.81 28.15 0.76 <0.14 28.15 11.30 3.54 0.10

Sampling Program Results in Septembre 2010

Foliar analysis

Eucaliptus leaf levels %N vs. Grow rate

In both cases is observed:

A.- High plants absorption, by means of consumption, of main nutrients ions (N, P, K).

B.- A relevant water absorption was found in the first sampling is observed, with no absorption effect of ions, especially Cl- and Na+; with a possible toxicity risk comprehend with N and K concentration. As result an increase of salinity due to the low irrigation flow is observed, and as consequence, a minor metabolic activity is reached.

C.- In the second sampling analysis such a problem is minimized after increasing the flow coefficient. Is also observed in less concentration of toxic elements, Cl y Na, in foliar analysis.

D.- An increase of Ca2+ in soil depths by limestone dissolution and a buffer effect with high pH. A more favorable Ca/Na relation in second sampling and less peptization risk.

F.- In both cases the chemical composition of solution at high depths is not pollutant and has no environmental restriction.

- Valorization of industrial effluents: chemicals, agrofood, mining, etc...

- Development and monitoring in energetic crops (Biomass, Biofuels)…

AGQ Experience

- Assessment of more than 600.000 hectares in Mediterranean area, North Africa, Caribbean, California and South America.

- Monitoring, control y rehabilitation of contaminated lands.

- Recuperation projects of saline soils in Spain (Ca/Na), River Nilo/Egypt, Copiapó (B) y Arequipa (Ba, Sr)

…

- Green areas.

HOW A PROBLEM ...

... BECOMES A RESOURCE

VIA ENERGETIC CROPS AND MONITORING CONTROL

VALORIZACIÓN EXCEDENTE DE AGUA Ciclo Completo

MiningOperations

Effluentfrom Process

or AMD

TreatedEffluent

EnergyGeneration

Agronomic ProjectEnergetic CropsBiomass

Fuel

Electric EnergyThermal Energy

Restoration

VALUE

Self EnergyClean EnergyReduction CO2

Image/Social

ADVANTAGES

• SOLUTIONS OF EFFLUENTS AND DEGRADED MINING AREAS

• ENVIRONMENTAL SUSTAINABILITY

• ECONOMIC BENEFITS FROM ENERGY PRICES AND SELF-SUFFICIENCY

• POSITIVE ENVIRONMENTAL IMPACT OF CO2 EMISSIONS REDUCTION

• IMPROVING GLOBAL IMAGE OF MINING ACTIVITIES

• SOCIAL BENEFITS, EMPLOYMENT GENERATION, ALTERNATIVES OF OTHER ACTIVITIES.

KEY ISSUES

• WATER TREATMENT PROCESS

• MANAGING AND CONTROL OF SYSTEM WATER - SOILS - PLANT IN ENERGETIC CROPS

• BIOFUEL MANAGEMENT

Irrigation Water

Energy Production 1 MWe

0.60 Hm3

7400 MWh/y

Energetic CropsLands

250 Ha

Biomass

Annual estimation

10000 t/y

emissions reductions5800 t/y CO2