This document discusses various technologies for nutrient recovery from waste streams. It describes three main steps in the nutrient recovery process: nutrient accumulation, nutrient release, and nutrient extraction. For accumulation, it outlines biological, chemical, and physical approaches like bacterial accumulation, chemical precipitation, adsorption, and algal and plant uptake. For release, it discusses biological digestion, thermochemical, and chemical/bioleaching methods. Finally, it examines extraction techniques such as precipitation, gas membranes, stripping and electrodialysis that produce fertilizer products from accumulated and released nutrients. The goal of these recovery technologies is to sustainably reuse nutrients from wastes.
2. Ø Reuse and recovery/recycling of waste is environmental friendly,
economically and socially acceptable.
ØLiquid waste - fluids as wastewater, fats, oils or grease, used oil, and
hazardous household liquids.
ØSolid waste - any garbage, sludge from a wastewater treatment plant,
miunicipal solid waste,industrial wastes,agricultural wastes,bio-medical
wastes.
ØThe removal of nitrogen and phosphorus from wastewater is needed
because these compounds cause eutrophication in natural water.
3. vThese are three-steps of nutrient recovery (given in sequential order) :
(1) nutrient accumulation,
(2) nutrient release,
(3) nutrient extraction
Wastewater consist of recoverable components such as nutrients, carbon,
and inorganics in addition to water and energy.
Nitrate is a risk to human health, especially cause methaemoglobinaemia.
4. GRAPHICAL ABSTRACT:
Waste Stream
Nutrient Recovery Pathway
Nutrient
accumulation
Nutrient
Realese
Nutrient
Extraction
Low
Nutrient
effluent
Recovered
nutrient
product
via
• Prokaryotes
• Chemical Precipitation
• Adsorption / Ion
exchange
• Algae
• Liquid - Liquid Extraction
• Plants
• Membrane Fixation
• Magnetic separation
via
• Biological
• Thermochemical
• Bio leaching
via
• Chemical Precipitation/
Crystalization
• Gas Permeable
Membrant
• Liquid Gas Stripping
• Electrodialysis(ED)
5. NUTRIENT ACCUMULATION TECHNOLOGIES
Ø It recover soluble nutrients ex. N, P, and K
Ø Biological, physical, and chemical techniques used for nutrient
accumulation.
Ø Chemical accumulation techniques have been largely limited to P, biological
methods used for accumulation of N and K.
Ø Physical accumulation via adsorbents can be used for all three nutrients.
Prokaryotic Accumulation:
Soild and liquid waste
phototrophic and heterotrophic organisms
accumulation of nutrients
6. ü Common nutrient accumulating microbes -
1) Proteobacteria ex. polyphosphate accumulating organisms(PAOs)
used for phosphorous removal
20–30% of P by weight
2) Purple nonsulfur bacteria
3) Cyanobacteria
q Sewage treatment plants
Bacterial-accumulation of P
through enhanced biological phosphorus
removal (EBPR)
Remove 80–90% of soluble P from the effluent
v EBPR requires alternating anaerobic and aerobic(pH 7–8) conditions so that
the uptake of P by microorganisms is above normal metabolic requirements.
7. Wastewater
PAOs
Phosphate-rich sludge
settling
settled sludge
biological methods
nutrients are released
Nutrients
asimilate and accumulate by
Purple nonsulfur bacteria and cyanobacteria
Store the
nutrients as
proteins or
polyphosphate.
Ø Cyanobacteria - blue–green algae - suitable for luxury uptake of N
- consists of 8–12% N and 1% P
8. Chemical Accumulation via Precipitation
Solid and Liquid waste
via coagulation and flocculation
Chemical accumulation of nutrients
Soluble nutrients bound to colloids (0.01–1 µm)
precipitated as solids and
separated by settling in
clarifiers
Ø Aluminum-or iron-based coagulants are commonly used for accumulating of P
from dilute wastewater.
Ø The coagulants, when added to water, hydrolyze rapidly and form multicharged
polynuclear complexes with enhanced adsorption characteristics.
9. Adsorption/Ion-Exchange
ØDuring adsorption and ion-exchange, ions are transferred from the solvent to
charged surfaces of insoluble, rigid sorbents suspended in a vessel.
ØThe sorbents are made from porous materials containing interconnected
cavities with a high internal surface area.
ØAdsorption and ion exchange can accumulate soluble N, P, or K from waste.
ØFor concentrated waste streams (>2000 mg/L):- 1) red mud, metal
oxide/hydroxide, and zirconium sorbents are used for P recovery and
2) modified zeolite and clinoptilolite for N and K recovery.
10. Algae Accumulation
§ Algae have received significant attention worldwide as a valuable source of
biomass for energy because of their high growth rates as compared to
terrestrial plants.
§ Algae can also be used to accumulate nutrients.
§ Nutrient accumulation is dependent on algal physiology, concentration of
nutrients (N and P), light intensity, pH, temperature.
Algae-based systems
non suspended suspended
algae are immobilized on a resin
The surface immobilized algae reduce nutrient
load,uptake nutrient by the algae biomas ex.
use in dairy,poultry,and swine manure wastes.
via adsorption and/or precipitation
Suspended algae configurations
are used in facultative and
high rate algal ponds.
11. Plant Accumulation
Nutrient accumulation can also be performed in wetlands
plants grow on the water surface
nutrients accumulate
creating anaerobic conditions in the surrounding water
The anaerobic conditions drive digestion reactions where
organic matter is metabolized
produce nutrients that can be further accumulated by the plants.
ØThese plants, however, must be routinely harvested to ensure that the accumulated
nutrients are not recycled.
ØFree-floating plants have a higher capacity for nutrient accumulation as they grow on the
surface of the water and the roots are kept suspended in the water column to allow
accumulation of the nutrients.
12. Magnetic Separation
Solid or Liquid waste
by employing adsorption to a carrier
material that has magnetic properties
soluble nutrients are accumulated
Nutrients-laden carrier material can be recovered
by capturing the magnetic particles with a
magnetic field
(HGMS)
v The magnetic carrier recover soluble N, P, or K from waste streams using
specific adsorbents,
v The magnetic carriers commonly used are magnetite, carbonyl iron,
and iron oxide.
13. Liquid–Liquid Extraction
Liquid–liquid extraction is a method of separating compounds based on relative
solubility in two immiscible liquids and can be used to recover soluble nutrients.
In this process,an extractant is dissolved in an organic phase
brought into contact with the waste
causes a transfer of nutrients into the organic phase until equilibrium is
reached with the aqueous (wastewater) phase
Take the organic phase (mixed with nutrients)
brought into contact with another secondary aqueous phase at conditions
where the nutrients are highly soluble in the secondary aqueous phase
v A mixture of kerosene (organic phase) and benzyldimethylamine (extractant) in a 2:1 ratio
worked best for phosphate extraction, and that combined use with 6.0 M sulfuric acid as
the secondary aqueous phase provided a high P recovery of >93%
14. NUTRIENT RELEASE TECHNOLOGIES
vOnce accumulated, nutrients must be either released or directly extracted
into a recovered product.
Biological Release
Thermochemical Stabilization and Chemical Release
Bioleaching/Extraction
Biological Release
Biodegradable waste
Anaerobic digestion
Release of nutrients
Organic N is converted into ammonium Organic P is hydrolyzed to soluble P
mesophilic bacteria
15. Solid or Liquid waste
go into thermochemical processes like thermal hydrolysis, wet oxidation,
incineration, gasification
greatly reduce the bulk volume of wastes
by destroying a large proportion of the carbon
These produced char/ash/oil that retains most P and K,but N is lost in the gas
stream
In Wet oxidation Metals
oxidation
temperatures (180–315°C),
at high pressures of 2–15 MPa
Oxidized to their highest valency and P to P2O5
16. The solid by-products (ash/char) from thermochemical treatment
further processed thermally In the presence of chloride salts
Heavy metals
Heavy metal chlorides to be vaporized and removed from the char/ash.
Heavy metals are then captured through flue gas treatment
Chemical extraction Solid by-products (ash/char)
acids or bases
at moderate temperatures and pressures
Digester reject solid waste or waste streams
Release nutrients into a
leachate
convrted into
17. Chemical extractants used in chemical extraction:
ü Inorganic acids (H2SO4, HCl, HNO3)
ü Organic acids (citric and oxalic acids)
ü Inorganic chemicals (e.g. ferric chloride solution)
ü Chelating agents (e.g. EDTA)
Bioleaching/Extraction
v Bioleaching is a release technology.
Waste or solid substrates
Either directly by the metabolism of leaching
microorganisms,
Or indirectly by the products of metabolism.
Solubilization of nutrients and heavy metals
18. v Microorganisms used for bioleaching activity are mesophiles
(Acidithiobacillus sp), thermophiles (Sulfobacillus sp) and heterotrophic
microbes (Acetobacter,Fusarium,Penicillium,and Aspergillus).
19. NUTRIENT EXTRACTION AND
RECOVERY TECHNOLOGIES
v Physicochemical methods used to recover the nutrients that were released
into a soluble form (e.g., N–NH4
+, P–PO4
3−, and K–K+) by the technologies
described above.
v Now these nutrient recovery techniques focuses on production of
alternative fertilizer products for use in agriculture.
1) Chemical Precipitation/Crystallization
2) Gas-Permeable Membrane and Absorption
3) Liquid–Gas Stripping
4) Electrodialysis(ED)
20. Chemical Precipitation/Crystallization
v Chemical precipitation via crystallization is a phase change process.
Previously dissolved components
converts into
a particulate, inorganic compound, for separation from the liquid bulk
v During this process, supersaturated conditions (a thermodynamic driving
force for precipitation) are created in the waste streams through a change in
temperature, pH, and/or by the addition of metal ions.
v Because of these conditions, precipitation of selected products can be
performed.
v Example : Struvite (MgNH4PO4·6H2O) crystallization technique being applied
to simultaneously recover N and P from nutrient-rich water.
21. Gas-Permeable Membrane and Absorption
v The membrane comprised of silica, ceramic, polyvinylidene fluoride (PVDF),
polypropylene (PP), polytetrafluorethylene(PTFE).
v Gas-permeable membranes can be used to recover N as ammonia from the
liquid phase.
v In this process, ammonia is transferred by convection and diffusion from
the liquid stream across a hydrophobic membrane.
v Ammonia recovery via membrane concentration, using acids such as
sulfuric acid ammonium sulfate
recover ammonium as
22. Electrodialysis (ED)
Ø ED is an extraction technology.
Ø Applied electrical field between electrodes.
Ø Selectively separates anions and cations across an ion-exchange
membrane.
Ø Cationic species (K+ and NH4
+) move toward the cathode passing through
cation-exchange membranes (CEM) which allow only positively charged
species.
Ø Anions (e.g. PO4
3−) move toward the anode passing through anion
exchange membranes (AEM) which allow only negatively charged species.
Ø ED has the potential to recover all nutrients.
Ø But is most applicable for N and K
Ø As P can be effectively removed using other lower cost methods.
23. Liquid - Gas Stripping
v Gas stripping is a physiochemical process.
v Mass transfer of ammonia from the liquid phase to the gas phase.
Dissolved ammonia in the liquid phase
mass transfer
Gas phase
Contacting with an extractant gas
(usually air)
v Mainly applicable to situations where the effluent has a relatively high
ammonia concentration.
v Recovery of the stripped ammonia occurs via condensation, absorption,
or oxidation to produce a concentrated fertilizer product.
24. CONCLUSION
v These advancements will reduce water, air pollution by reuse nutrients
from waste into recovered nutrient products.
v It provides a long-term sustainable supply of nutrients and helps buffer
nutrient price rises in the future.
v We develop agriculture application of the recovered nutrient products.
v Need to further development of accumulation–release–extraction
technologies to improve nitrogen and potassium recovery .
25. • Chirag M. Mehtaa, Wendell O. Khunjarb, Vivi Nguyenb, Stephan Taita : A
Critical ReviewTechnologies to Recover Nutrients from Waste Streams
• Cordell, D., Rosemarin, A., Schroder, J. J., and Smit, A. L. (2011). Towards
global phosphorus security: A systems framework for phosphorus recovery
and reuse options. Chemosphere, 84, 747–758.
• Cai, Ting; Park,Stephen Y; Li, Yebo; Nutrient recovery from wastewater
streams by microalgae: status and prospects, Renewable and Sustainable
Energy Reviews 19 (2013) 360–369
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