Intermittent Discharges (inc CSOs)

Transcription

1 Intermittent Discharges (inc CSOs) What are intermittent discharges? Existing Standards Outcome of the Standards Review Implications Paul Simmons Environment & Business, NW Region

2 Intermittent Discharges - The Scale of the Problem 6,500 sewage treatment works 25,000 intermittents 8,000 have been improved since 1995 cost approx 3.5Bn 50% of bathing waters affected by CSOs ~320 waterbodies impacted by intermittents High Profile discharges

3 Legend AP5UIDsNEP Other drivers Other drivers BW BW & SW SW due for monitor 350 CSOs requiring improvement 320 WFD WBs at risk

4 Impacts of intermittent discharges

5 UP (Urban Pollution anagement) Standards FIS Fundamental intermittent standards which are directly related to the characteristics of events which cause stress in river ecosystems. These standards are expressed in terms of concentration-duration thresholds with an allowable return period or frequency. Dissolved Oxygen, unionised ammonia. High percentile standards (99 percentiles) based on a direct extrapolation of the 90/95 percentile thresholds from other standards. BOD, ammonia.

6 Review of UP Standards against WFD requirements Task A Carry out a literature review/data collection. Task B Establish an effects matrix. Task C Compare the effects matrix against existing standards. Task D Propose UP standards for WFD.

7 Un-ionised ammonia sustainable salmonid fisheries FIS Taxa Species Type of 24-hour LC 50 organism (mg NH 3 -N/l) Reference Fish S.salar Atlantic salmon 0.12 Alabaster et al (1979) Invertebrate V.iris ussel 0.22 ummert et al (2003) Fish O.tshawtscha Chinook salmon 0.30 Harader and Allen (1983) Invertebrate L.fascioloa ussel 0.32 ummert et al (2003) Invertebrate A.ligamentina ussel 0.47 Wang et al (2007) Fish H.molitrix Silver carp 0.48 Xu et al (1994) Fish O.mykiss Rainbow trout 0.53 ilne et al (1992) Fish N.guentheri Killifish 0.57 Shedd et al (1999) Invertebrate L.siliquoidon ussel 0.60 Wang et al (2007) Fish S.trutta Brown trout 0.60 ilne et al (1992) Fish L.guntea Guntea loach 0.61 Sangii and Kanabur (2000) Fish C.carpio Common carp 0.68 Xu et al (1994) Invertebrate L.rafinesqueana ussel 0.68 Wang et al (2007) Fish L.cephalus Chub 0.76 Gomulka et al (2011) Algae S.costatum Diatom >1.00 Livingston et al (2001) Fish P.promelas Fathead minnow 1.22 arkle et al (2000) Fish P.reticulata Guppy 1.35 Rubin and Elmaraghy (1976) Invertebrate.rectirostris Cladoceran 1.61 Gyor and Olah (1980) Invertebrate D.magna Cladoceran 1.74 Kaniewska-Prus (1982) Invertebrate L.stagnalis Snail 1.92 Williams et al (1986) Invertebrate P.tennuis Turbellarian 1.95 Williams et al (1986) Invertebrate L.intermis Insect 2.18 Williams et al (1986) Invertebrate P.fontinalis Bladder snail 2.20 Williams et al (1986) Invertebrate B.rhodini ayfly 2.30 Williams et al (1986) Invertebrate L.hoffmeisteri Tubificid worm 2.80 Williams et al (1986) Invertebrate C.riparius idge larvae 3.00 Williams et al (1986) Invertebrate B.rubens Rotifer 3.20 Snell and Persoone (1989) Invertebrate G. pulex Amphipod 3.20 Williams et al (1986) Invertebrate E.ignita Damselfly 3.29 Williams et al (1986) Invertebrate A. aquaticus Isopod 4.04 Williams et al (1986) FIS for Sustainable Salmonid and Cyprinid fisheries are suitable for WFD

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9 99%ile mg/l 99 Percentiles for WFD 99%iles for BOD HIGH RE1 y = x R 2 = GOOD RE2 RE RE4 90%ile mg/l RE5

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11 How will the standards be used? Design Standards, not classification Water company improvements / investigations for PR14 Need driven by WFD classification, use is through modelling WOE / risk-based approach - Confidence in relevant element(s) not achieving Good status - Significance of the contribution of intermittent discharges to the problem

12 Implications application of FIS In England and Wales the salmonid standard will replace the cyprinid standard for some waterbodies Information for 320 Waterbodies identified in Reasons for Failure Database with intermittents as cause Current Fish Directive Designation Expected Prevalence of: % No Fish Class points No. Sample points 620 probability level Salmonid Salmon 90 29% 61 19% 20 6% Cyprinid Trout % % % 12 % to 44 % of waterbodies may require tighter FIS standard for WFD. 40 to 140 of these 320 waterbodies where salmonid standards will now apply instead of cyprinid

13 Implications 99 percentiles Steep, fast flowing rivers Low confidence in detailed river modelling Standards derived for high, good, moderate, poor status Good status standards for old RE3, RE4 objectives are tighter Good status standards for old RE1 and RE2 objectives are less stringent 1,000 to 2,000 km of river may require tighter standards (England and Wales)

14 Questions / Comments