Mine Impacted Water: A resource for the circular economy in South - - PowerPoint PPT Presentation

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Mine Impacted Water: A resource for the circular economy in South - - PowerPoint PPT Presentation

Sep 24, 2023 559 likes •989 views

Mine Impacted Water: A resource for the circular economy in South African Mining communities Dheepak Maharajh; Tamsyn Grewar; John Neal and Michelle van Rooyen Water-Energy-Food Nexus: towards efficient national planning on 23-24 October at

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SLIDE 1

Mine Impacted Water: A resource for the circular economy in South African Mining communities

Dheepak Maharajh; Tamsyn Grewar; John Neal and Michelle van Rooyen

Water-Energy-Food Nexus: towards efficient national planning on 23-24 October at Amanzingwe Lodge & Conference Centre, Broederstroom, Hartbeespoort

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SLIDE 2

INTRODUCTION

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  • SA water scarce
  • ~460mm vs ~850 global avg
  • Considered water stressed
  • Mining sector water use ~ 3 to 5%
  • Agriculture - ~ 50 to 70%
  • Bad water use behaviour
  • Use 60% more per person
  • Mine impacted Water
  • Negative environmental impact
  • Ground water contamination
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SLIDE 3

MINING SECTOR NOT HELPING!!!

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SLIDE 4

HUMAN FACTORS

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Water scarcity

Poor Water use behaviour Mining sector pollution Agriculture – 70% clean water Inefficient waste water treatment

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SLIDE 5

CHALLENGES FACING MINING SECTOR

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  • To reduce the utilization of key

resources such as energy and water,

  • To reduce the environmental

impacts of the operations and of waste production,

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SLIDE 6

SOCIO-ECONOMIC IMPACT

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SLIDE 7

IMPACT OF WEAKENING MINING SECTOR

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  • Estimates 30 years mine lifespan remains
  • What happens after mining?
  • Drastic impact on poverty
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SLIDE 8

NEED FOR MECHANISATION

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  • Could increase to 100

year lifespan

  • Job cuts
  • Spread of poverty
  • Catch 22
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SLIDE 9

CHALLENGES FACING MINING SECTOR

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  • To reduce the utilization of key

resources such as energy and water,

  • To reduce the environmental

impacts of the operations and of waste production,

  • Ensure sustainable mine closure
  • Create new employment to make

way for mechanisation.

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SLIDE 10

HOW CAN WE HELP?

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SLIDE 11

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 12

MINTEK’s AVAILABLE TECHNOLOGY OFFERINGS

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SLIDE 13

AMD TREATMENT: BIOLOGICAL SULPHATE REDUCTION (BSR)

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  • Operated in down-flow mode
  • Daily measurements of pH levels, redox potentials, electrical conductivity and

sulphate concentrations

  • At steady-state condition, samples removed for detailed chemical analysis
  • Substrate (initially, at

least):

– 20 % cow manure – 20 % hay – 20 % wood shavings – 40 % wood chips

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SLIDE 14

BSR RESULTS SUMMARY

14 Element/ compound Feed (mg/L) Column 1 (mg/L) Column 2 (mg/L) Column 3 (mg/L) SO₄²⁻ S²⁻ NH₄⁺ Be HCO₃⁻ Na Mg Al Si PO₄³⁻ Cl K

Ca Cr Mn Fe Co Ni Cu Zn As, Mo, Ag, Cd Pb Alkalinity pH level 3340 9 5 <0.02 106 258 537 4.7 5.2 <0.01 <0.01 172 587 0.07 36 0.49 0.06 0.07 <0.02 <0.02 <0.02 <0.02 87 6.93 140 802 709 <0.02 7802 195 514 3.7 23 <0.01 0.35 456 475 0.09 2.0 1.16 <0.02 0.09 0.03 0.02 <0.02 0.1 6395 6.97 130 360 858 <0.02 7676 209 447 3.0 27 0.1 0.34 531 544 0.18 3.4 0.95 <0.02 0.06 0.04 0.02 <0.02 <0.02 6292 7.20 90 200 697 <0.02 7260 241 399 2.2 29 0.1 0.34 548 400 0.33 2.5 1.56 <0.02 0.16 0.02 0.02 <0.02 <0.02 5951 7.23

  • Detailed chemical analyses

performed on day 486

  • 140 mg/L SO₄²⁻ in Column 1
  • 90 mg/L SO₄²⁻ in Column 3
  • Sulphate removal >97 %
  • 200 mg/L S²⁻; 2.5 mg/L Mn
  • S²⁻ and Mn can be removed

in oxidative polishing process

  • NH₄⁺, HCO₃⁻, PO₄³⁻
  • Fitness for use of final

product is under evaluation – crop irrigation, algae culture

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SLIDE 15

BSR PILOT

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SLIDE 16

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 17

SAVMINTM

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  • Patented in 1998
  • Evolved over the last 20 years
  • Latest improvements with Veolia
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SLIDE 18

SAVMINTM DEMONSTRATION – SULPHATE REMOVAL

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250

  • >92% SO4 removal
  • Metals removal
  • Cost ~ R10 – R21/m3 – potable quality water
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SLIDE 19

SAVMINTM PILOT SCALE DEMONSTRATIONS

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  • At Stilfontein gold mine, Navigation Colliery and Grootvlei gold mine
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SLIDE 20

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 21

TECHNOLOGIES FOR INTEGRATION

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SLIDE 22

ALGAE CULTURE

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Nutrition Environment Energy Health care

Algal Technologies

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SLIDE 23

Algae

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  • Secondary water treatment – clean MIW
  • Mops up residual SO4, PO4, NO3, metals etc
  • Biomass
  • High in protein – animal feed
  • High carotenoids – high value
  • Lipids
  • Contains 20 to 70% lipids
  • Converted to Biodiesel
  • Biodiesel - ~ 70m litres/yr/mine
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SLIDE 24

Algal culture

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SLIDE 25

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 26

AGRICULTURE

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  • MIW – agricultural irrigation
  • Produce crops for food, biofuel or even mining

use e.g. flotation and thickening agents

  • Food crops - communities
  • Biofuels crops – mining vehicles
  • Mine related products eg. Guar bean
  • Community job creation
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SLIDE 27

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 28

AQUACULTURE AND ANIMAL HUSBANDARY

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  • Direct AMD use – not possible
  • After algal culture cleaner water
  • Algae protein – feed source
  • Fish – mess up water
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SLIDE 29

AQUACULTURE

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  • Ideal fertilizer or algal feed
  • Recycle back to algae and

agriculture in flow sheet

  • Product sold for profit
  • Waste to anaerobic digestion
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SLIDE 30

Animal husbandry

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  • Livestock farming
  • Algae protein for feed
  • Livestock sold for profit
  • Manure feed for Anaerobic

digester

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SLIDE 31

HOW CAN WE ADDRESS THESE CHALLENGES?

31

MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 32

ANAEROBIC DIGESTION

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  • Animal waste
  • Food waste
  • Domestic waste
  • Produce Biogas
  • Used for cooking
  • Electricity – community and mines
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SLIDE 33

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 34

CONCENTRATED SOLAR POWER

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  • Power generation – supply

communities

  • Smelter operations
  • Desalination of MIW
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SLIDE 35

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 36

CO2 CAPTURE STORAGE

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  • SA generates ~420 Mt CO2 per annum (1% of global emissions)
  • Current CO2 levels ~400ppm
  • Expected to breach 800ppm by end of the century

South Africa’s position as a Global CO2 emitter (Naidoo, 2013)

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SLIDE 37

CO2 CAPTURE STORAGE

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  • Carbon capture and storage (CCS) - physical capture and storage
  • f CO2 from fossil fuel combustion in such ways that it does not

enter the atmosphere

  • Carbon mineralisation (CM) - reaction of CO2 with alkaline earth

metals (or other wastes containing Ca and Mg) to form stable, inert and environmentally benign carbonate minerals, sustainably trapping CO2 in solid form

  • Work is currently being under-taken at Mintek to investigate

the potential of using mining- related waste for this purpose

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SLIDE 38

HOW CAN WE ADDRESS THESE CHALLENGES?

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MIW SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Metal recovery Energy Crops Animal Feed Animal Husbandary Anaerobic Digestor Biodiesel Production Oil Extraction Biomass FOOD Gas turbine Electricity Food Transport Fuels Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich waste CO2 Carbon Mineralization CO2 Glycerol Concentrated Solar Power Heat Storage

Community Housing, Offices, Mine Buildings

Food Waste Sewage Grey Water Rain Water Waste BIOMIN Digestate

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SLIDE 39

THE CIRCULAR ECONOMY

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SLIDE 40

THE CIRCULAR ECONOMY

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  • Cradle to cradle approach
  • Waste or by-product never discarded
  • Re-use principal
  • Multiple products
  • Creating community value
  • Jobs
  • Food security
  • Energy security
  • Mines can move labour
  • Increase mechanisation
  • Extend mine life cycle
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SLIDE 41

JOB CREATION POTENTIAL

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SLIDE 42

JOB CREATION POTENTIAL

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MIW Gas turbine Transport Fuels Carbon Mineralization Heat Storage Food Waste Sewage BIOMIN Metal recovery SAVMIN Irrigation Food Crops Aquaculture AMD Neutralization Passive BSR Algal Culture Energy Crops Animal Feed Animal Husbandary

Anaerobic Digestor

Oil Extraction Biomass FOOD

Electricity

Food

Transport Fuels >300ppm S >300ppm S Nutrient rich waste Nutrient rich CO2 CO2 Glycerol Concentrated Solar Power

Community Housing, Offices, Mine Buildings

Grey Water Rain Water Waste Digestate

500 to 2000 direct jobs per mine ~ 2000 to 8000 indirect jobs