(Selected) Technology trends within water and waste water treatment

Harsha RatnaweeraProfessor in Water & Wastewater Technology

Norwegian University of Life Sciences

Outline• Market drivers

• Technological sectors – Particle separation (Membranes & sieves)– Biological processes – next generation– Disinfection (Advanced and safer oxidation)– Reuse of water and resources (energy)– Optimal transport (leakage minimisation)– Residuals management– Smart water systems (sensors, software, real-time control)

Market drivers for global water investments (and developments)

Access to safe drinking water

Availability

Access to safe drinking water

Ratio of wastewater treatment

71 main Indian cities produce 70 million m3 ww/day (132 mill m3/d in 2050), but the treatment capacity is 12 million m3/d…

Global water market

Frost & Sullivan

Drivers and responses• With stricter nutrient standards,

–investment for filtration has increased in recent years• With strained water resources globally,

–water reuse has increased• increased pressure to move to inherently safer

technologies: –Innovative disinfection

• New legislations–Increased treatment requirements–Ballast water treatment ($30 billion global market)

Mega trends in water industry: 2020

Technology focus

Frost & Sullivan

Technological developments

Particle separation

• From nutrients to colloids• Distribute the loading on unit processes optimally

–Fine sieves to remove more particles reducing load on biological & chemical processes

–Membrane filtration to remove more and non-traditional pollutants cheaper and more efficiently

• Reducing the plant footprint, energy – chemical- manpower use

Particle removal

Fine Sieves:

• 40-60% of organic fraction of TSS are from toilet paper tissues

• Majority can be removed with sieves >500 microns.• Combination of sieves with chemicals

Salsnes/Trojan: 50% TSS & 20% BOD removal

Reduction of plant footprints

Frank Rogalla, Aqualia

Reduction of plant footprint

BAF – Biological Aerated Filters: Biostyr

1 500 000 PE Biostyr

1 500 000 PE Activated Sludge

Reduction of plant footprint

Membrane bio-reactors

15

MBBR – Continuous flow intermittent cleaning

Biowater- CFIC

MBBRAS CFIC

Reducing footprint of separation stage

Actiflow: from 2 hours to 10-20 mins

Polymers??

Advances in biological treatment

Nitrogen cycle revisited

• Short cut in N-removal• No need for external C-

source

• Must prevent NO2NO3

• Slow growing organisms

• High cost of aeration in Aerobic systems• Historically AN was not popular due to low concentrations

in municipal WW, slow growth etc.

• Anaerobic membrane bioreactor (AnMBR): no gravity settling, small footprint and short HRT

Advances in biological treatment

Anaerobic WWTP revisited

Enzymology in Biological WWT

• Use of selective enzymes in biological WWT–Can shorten the space requirement by 50% in cold

climates–Faster start-up–Less odour–Controlling filamentous microorganisms

Disinfection

• Safer, cheaper and more efficient..

UV disinfection• CFD for optimised contact• Medium pressure lamps with quartz coating: >12000 hrs• LED technology: >100 000 hrs (>11 years)• Use of microwaves to energise the UV lamps without

electrodes: dramatically improvement in footprint• Better understanding of D10 doses for various

microorganisms

• Combatting reactivation• Disinfection by-products: no THMs, but more exotic

ones?

Reuse of water• Recycled water is becoming to be recognized as a

beneficial resource and not a waste lost in the ocean–Policy targets and mandatory reuse–20 to 100% recycling ratio of treated wastewater

(California, Cyprus, Florida, Israel, Spain)–satisfy up to 15-35% of water demand (Australia,

Singapore)

Membrane technologies

• Membrane bioreactors for wastewater treatment–reactor geometry, the hydrodynamics and placement

of membrane modules and the overall operating parameters.

• membranes for desalination–Pre- treatment methods–CFD to optimize module characteristics (mass

transport rates, limited fouling/scaling tendencies, less energy)

• Seawater desalination with solar-power

Forward osmosis• Emergency drinks, water in space shuttles, desalination,

evaporative cooling water

Nano technology

• Nanoadsorbents, magnetic nanoparticles, nanofiltration, nano zero valent iron, nanocatalysts, nanobiocides, nanofibers and mixed technology including catalytic wet air oxidation along with nanoparticles are the products and techniques which are evolved as a result of development in nanotechnology and are being used in wastewater treatment.

–Removal of highly toxic matter when present in very low concentrations (membranes doped with TiO2 photocatalysts activated by sunlight

Microfluidics- removal of toxins• In a microfluidic device, fluids flow through narrow

channels at high speeds- the particles flow single file within the channel: possible to select & separate.

• Membrane filtration systems

Phosphorus crisis

• Coagulation – reduces the plant availability of phosphorous

– After treatment of sludge– Struvite (magnesium ammonium phosphate) production– Reduce Al/Fe use

Residuals managementSludge production and use in agriculture

Norway 100 000t 83%China 10 000 000t

• Thermal conversion– Gasification and pyrolysis (TS of 10-50% instead of 90%)– Supercritical water oxidation (SCWO) process (wet oxidation/

wet combustion): makes sludge highly soluble and homogeneous: small footprints, inert residuals, less sludge & emissions

– Steam explosion (Cambi)

• Biogas production

Biofuels from microalgae.

EU FP7 All-gas project

Distribution and transport systems

Real-time surveillance and control

• Predictive network modelling and optimisation capabilities to asses the effects of operational or physical changes in system performance and integrity

–Real-time network models–Real-time operational optimisation models (anomality

detection)

Smart IT technologies will become an integral component of modern water networks in the 21st century• earlier detection• Approximate location from data

simulations

Sewer systems

Coping with climate change

• More and frequent rains–Overloaded sewers and WWTPs will have even more

challenges.

• How to cope with the need?–Infrastructure expansions–Soft approaches: real time control of sewers and

WWTPs (Regnbyge-3M)

Novel sensors and estimation tools

• Water quantity- using weather radar and physical measurements

• Models to estimate water quality with simpler measurements (flow, etc)

• Advanced data processing• Remote surveillance & control

• Image analysis• Novel technologies for cheaper and faster detection• Bioindicators

Optimal dosages and images of flocs

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Floc features detection limit GLCM

A period of many changes with lot of room for new

developments

Paradigm shift