TREATMENT STRATEGY R2IC Trials 1 URBAN VISION 2 THE CIRCULAR - - PowerPoint PPT Presentation

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R2IC Trials

WASTEWATER TREATMENT STRATEGY

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URBAN VISION

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THE CIRCULAR ECONOMY

• The linear economic model where we “take, make and

dispose” of things is not sustainable.

• It relies on large quantities of cheap easily accessible

materials and energy.

• “A circular economy is one that keeps resources in use for as

long as possible…then recovers and regenerates products and materials at the end of each service life”

www.wrap.org.uk

• In the Water Industry, we can play an important role in the

emerging circular economy - we receive huge amounts of “waste” water that is full of material that can be recovered and regenerated.

From CIWM Journal Online – www.ciwm-journal.co.uk

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WASTEWATER TREATMENT AND THE CIRCULAR ECONOMY

• There’s a lot of good stuff in sewage!

Verstraete et al. (2009) Bioresource Technology 100, 5537–5545 Salehizadej and van Loosdrecht (2004) Biotechnology Advances 22, 261–279

Material Amount per head per year

Reusable water 91.3m3 Cellulose 6.6kg Biopolymers 3.3kg Phosphorus (for incorporation in P compounds) 0.9kg Nitrogen (for incorporation in N compounds) 4.6kg Methane 12.8m3 Organic fertiliser 9.1kg

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THE WWTW OF THE FUTURE?

• Can we build a sewage treatment

flowsheet that gives us a truly energy positive WWTP?

• How can we reduce the energy

consumption of the treatment process?

• How can we recover and generate more

energy from sewage treatment?

• Can we recover and extract the value from

the useful material that exists in wastewater?

Enhanced Primary Retain Sludge AD for optimum energy balance Recover nutrients AnMBR

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RESOURCE RECOVERY & INNOVATION CENTRE #R2IC

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RESOURCE RECOVERY AND INNOVATION CENTRE

• Dedicated wastewater research and

development resource

• A controlled, safe and flexible plug-and-play

testbed

• ICA development facility
• Crude and settled sewage feeds from main

works

• Tanker reception facility
• Dedicated biogas and chemical dosing systems
• Conference room
• A fully equipped waste laboratory

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CURRENT PROGRAMME FOCUS

Carbon neutral + resource recovery Urban wastewater strategy

Energy efficiency Chemical efficiency Resource recovery Water quality Catchment focus Pumping 53 Sludge 58 Rural Works 19 Other 145 ASPs 140 Large Works 285

Biggest opportunity to Totex efficiency

Severn Trent energy use - GWhrs/a

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INNOVATION TRIALS

• Enhanced Primary Treatment (EHPT) – Microflotation
• Improving Secondary Treatment – Membrane

Aerated Biofilm Reactors (MABR)

• Mainstream Anaerobic Treatment – Combining UASB, U/F

membranes & Degassing system

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ENHANCED PRIMARY TREATMENT

Enviplan AQUATECTOR Microflotation Developed for aquaculture and proven in industrial applications, not UK wastewater treatment. High efficiency (DAF) separation process using 30μm air bubbles to separate solids. Much finer than similar water treatment

• processes. No coalescing of bubbles.

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ENHANCED PRIMARY TREATMENT

Trials

• Enhance BOD & SS removal
• Improve sludge quality
• Optimise recycle rates
• Test under diurnal/storm conditions,

consideration for peak lopping

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IMPROVING SECONDARY TREATMENT

Membrane Aerated Bio-film Reactors (MABRs) Uses hollow fibre membranes to support and aerate biofilms. Existing technology but rarely retrofitted – so little used. Side-by- side trial of two MABRs (Oxymem & Suez) in existing ASP lanes. Third ASP lane to run as control.

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IMPROVING SECONDARY TREATMENT

Trials

• Ease of installation
• Determine O & M requirements
• Compare ‘plug & play’ of Suez with

bespoke fitting of Oxymem units

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ANAEROBIC MAINSTREAM TREATMENT

• Anaerobic treatment of wastewater uses the same biological

processes as sludge AD.

• Anaerobic processes have been used to treat higher

strength industrial wastewaters for many years.

• Most applications use upflow anaerobic sludge

blanket reactors (UASBs);

• Flocculant, or
• Granular
• Applicability – small decentralised systems right through to large

urban works.

• But of course there are challenges…….

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CHALLENGES FOR UK IMPLEMENTATION

• Temperature – works in Brazil, not used in UK.
• Nutrient Removal – will not remove ammonia or

phosphorus – but enables effective mainstream N&P recovery.

• Dissolved Methane – low gas yield as dissolved at

lower temperatures – Membrane degassing needed.

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AnMBR

Biogas UASB feed Recirculation MT MBR effluent PST UASB MBR feed N2

• UASB + Membranes allow:
• Reduced HRT (smaller reactors) as solids efficiently retained (HRT’s of 4 – 6h possible).
• High quality effluent.
• But membrane systems require additional energy (& chemicals).

Performance

Parameters Unit Permeate Removal% Compliance TSS mg L-1 < Detection limit >99 25 COD mg L-1 41±16 83±7 125 BOD mg L-1 11±7 90±6 25 SCOD mg L-1 41±16

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ANAEROBIC MBR

Anaerobic membrane bioreactor (AnMBR) Deliver 500m³ /d demonstration plant by integrating

• ff-the-shelf UASB, UF membrane and Degassing

system. Optimise design and address challenges of wastewater temperature and composition, dissolved methane and biogas management. Two year programme to finalise design and establish performance.

INNOVATION NEEDS

• peninnovation@severntrent.co.uk

Carbon neutral + resource recovery Urban wastewater strategy

Energy efficiency Chemical efficiency Resource recovery Water quality Catchment focus

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SOME FINAL THOUGHTS

• We have a great opportunity in the water industry to transition

from energy intensive sewage treatment to energy neutral resource recovery factories

• The Resource Recovery & Innovation Centre at Spernal will help us

to realise this vision. …open for business