Industry Perspective on CIS Mixing Zone Guidance

1. Industry Perspective on CIS Mixing Zone Guidance Using the CIS Mixing Zone Guidance JRC Workshop ISPR, Italy 5-6th April 2011 by The Eurelectric Representatives on the CIS Drafting Group: Neil Edwards (RWE Npower, Asset Operational Support) & Keith Sadler (E.ON New Build & Technlogy)

2. Outline • Experience of the Drafting Process • Why is the Guidance Vital for Industry? • Benefits from the Guidance • Timeframes, Costs/Benefits • Key Aspects of the Guidance • Example – power station applications: • Tier 0/1 • Tier 2 • Tier 3/4 • Conclusions

3. Experience of the Drafting Process • Diverse mix of interests & experience represented on drafting group • some had limited experience of mz regulation in practice to date in EU or elsewhere • Positive commitment to work together • Lengthy, iterative & repetitive • Fundamental debate: • simple cheap, rigid, inflexible rules • or flexible best practice guidelines for case by case basis • Limited WrFD related guidance precedents (eg CIS 7, 19 & 25 on ‘Monitoring’)

4. Why is the Guidance Vital for Industry? • For many BAT compliant installations/processes aquatic emission streams contain substances at concentrations >EQS • Especially with modern methods setting far more precautionary EQS concentrations than previously • If MZ were not allowed EQS would be ELV which could: • rule out some technology that could otherwise be BAT/BPEO • add unwarranted cost • lead to unwarranted environmental impacts in non-aquatic media eg • offsite transport, treatment & disposal, life cycle considerations, energy use, sludge/landfill considerations etc

5. Benefits from the Guidance • Timeframes • Speeds determinations since principles are already established in authoritative source • Costs & Benefits • Minimise costs for regulated, regulator and stakeholders • Focuses efforts to appropriate aspects of applications • Promotes consistent and predictable determinations • Regulated can better integrate constraints into choice of options & designs • Sets out key points to address in complex & marginal cases • Allows exercise of expert judgement

6. Key Aspects of the Guidance • The acceptability of a mixing zone should be determined by the significance of its impacts not by its dimension • Recognises response of biota in the field not the same as in laboratory toxicity testing • eg avoidance rather than toxicity in some species • eg influence of out of mz biological systems on interior of mz • Tiered approach – risk-based cost effective regulation • allows comprehensive assessment • focuses regulators, regulator and stakeholder effort on discharges and aspects that need careful consideration • Flexible to meet range of pan-European circumstances • Incentivise use of case-specific sound science & data • Progressive Mixing Zone extent reduction not to be used to force emission reduction … • … which should follow from IED BAT, PS/PHS reduction/cessation trajectory measures etc

7. How & When Will Industry Use MZ Guidance? • Factor into feasibility, technology, location & case-specific design optimisation choices • New plant • Existing plant modifications • Permitting processes for new plant or existing plant modifications • Assessment of existing plant if physical, chemical, biological or regulatory context changes • Mixing zones considered from the earliest phase & throughout new project development • Baseline surveys, option choices, detailed design, modelling, permit applications, modelling validation, impacts assessment monitoring

8. Tier 0/1 Timescale: Built up iteratively during course of project as process design is refined. A week or so of effort overall. Often needs revision as detailed design evolves to ensure consistent inventories Costs: <£10k€ • Screening out emissions for which detailed consideration is not appropriate eg • Discharge does not contain relevant substance • Discharge has relevant substance but below EQS • Discharge has relevant substance at and above EQS but emission is ‘trivial’ in the context of receiving waters • Load considerations only - no need for dispersion calculation

9. Tier 2 Timescale: May be used to scope outfall options, location & initial design. Each run takes a few mins to define, seconds to run, interpretation can be tricky. A week or two per written up study + subsequent stakehodler dialogue Costs: k€5-20/study • Use of precautionary default MZ extent criteria • eg min{10*river widths,1 km} • Simple calculations of discharge plume mixing giving spatial distributions of concentrations which take some limited account of case specifics (eg CORMIX, Fischer, Plumes …) • Discharge volume flow, concentration and outfall arrangements + ambient depth, flow & concentration • Can establish no credible threat to vulnerable receptors or water body objectives … • without detailed representation of the case eg assume • straight bank, uniform bed, uniform steady flow, simple mixing model • … but sometimes scale and specifics such that insufficient confidence to permit or refuse permit with this level of consideration

10. Tier 3/4 Timescale: Developed with stakeholder input over months - years (eg best practice 1 complete year of baseline data for a new plant EIA) Costs: €100k-€1M/study depending on details • Detailed receptor mapping • + detailed dispersion modelling • Appropriate to case – often 3d such as Delft3d • + specific receptor sensitivity assessment • + specific receptor impact assessment • + acceptablity determination process

11. Wide Range of Cases!

12. A Power Station on an Estuary • Hypothetical example • Typical major estuary with port, sewage treatment works, heavy industry (some with discharges to water) • Coal-fired power station with flue gas desulphurisation (limestone gypsum process) • Ash lagoon & coal stock drainage to small natural water course … • … which also receives effluent from a nearby light industrial estate & agricultural land (dairy) upstream • Once through cooled (50 m3/s) - discharge to estuary of • heat • chlorination oxidant (UK annex VIII) • water treatment plant effluent • FGD effluent via cooling water discharge

13. Tier 0/1 assessment • Screening for substances for detailed assessment (H1 in England & Wales) • Limits detailed assessment to 3 of 20 substances in initial list of substancs entering drainage ditch • Limits detailed assessment of discharge to estuary to heat and chlorination oxidant only • Find concentrations increments from water treatment plant and FGD effluent are small and screen out with Tier 1 criteria • Eg point of discharge concentrations small compared to • EQS-AA • EQS-MAC • or ambient (if ambient concentrations > EQS & need to consider ‘no deterioration’ policy)

14. Tier 2 assessment • Use eg CORMIX to indicate no issue with drainage ditch influence on estuary • Use of precautionary extent acceptability criteria • Eg 1km for ‘wide’ estuary & no ‘special’ receptor within the predicted zone of exceedence • Alternatively could use full detailed modelling if available (but may not be suitable directly if developed for other purposes)

15. Tier 3/4 • Detailed receptor mapping • Detailed dispersion modelling appropriate to case: • often 3d such as Delft3d • + specific receptor sensitivity assessment • + specific receptor impact assessment • + acceptablity determination process

16. Tier 4 – Fieldwork (flows, plumes, mixing, ambient concentrations)

17. Tier 4 – Fieldwork receptors

18. Biotope Mapping

19. Receptor Sensitivity Mapping

20. Hydraulic Modelling Techniques

21. Numerical Modelling Low water spring Early ebb neap

22. Numerical Modelling- Animation • EQS-MAC concentration exceedence variation • bed and surface • through an equinox spring neap cycle • shoreline discharge over an intertidal area with wetting & drying

23. Case-specific assessment of the envisaged impact of the proposed mixing zone on the specific receptors potentially affected Impact characterisation Positive/neutral/negative Scale (spatial, temporal) Significance (conservation value) Integrated assessment Will conservation objective and/or water body objective be compromised by the candidate mixing zone Consequence Assessment

24. Conclusion • CIS MZ Guidance: • Fit for purpose • Encourages efficient & flexible risk-based regulation focusing on key aspects • Vital to allow application of technologies & options that might otherwise be ruled out leading to unwarranted costs or unwarranted impacts on other media

25. Thank you for your attention!

26. Sewage Treatment Works Water Treatment Plant effluent, FGD effluent, DeNox effluent … Power Station Cooling System Coal Stock Drain Site drain Ash Mound drain

27. EQS exceedence • Does not mean necessarily harm to all receptors when EQS concentration exceeded eg Chloroform (EQS Datasheet 2005) • 2008/105/EC EQS 2.5 ug/l (protection of bacteria in sediment breaking down organic matter) but note • NOEC fish 1.463 mg/l EQS*585 • NOEC invertebrate 6.3 mg/l EQS*2520 • NOEC algae 3.61 mg/l EQS*1444