The Continued Maturation of Environmental Assessments Over the Last Two Decades: End-of-Pipe to Watershed Strategies

Transcription

1 The Continued Maturation of Environmental Assessments Over the Last Two Decades: End-of-Pipe to Watershed Strategies William L. Goodfellow, Jr.

2 Brief History of Biomonitoring Ellis (1937) Detection and Measurement of Stream Pollution -used used Daphnia magna. Hart et al. (1945)-advocated using fish to evaluate effluent toxicity. Sprague (1973) The ABC s of Pollutant Bioassays Using Fish, in Biological Methods for Assessment of Water Quality -one of the first overview methods papers formal development of acute and chronic toxicity testing protocols for effluents (and various revisions).

3 Brief History of Biomonitoring (con t) Walsh and Garnas (1983)-publication described techniques for fractionating wastewater to examine toxicants t in wastewater. t US EPA (1987) Biomonitoring to Achieve Control of Toxic Effluents. Mount and Anderson-Carnahan (1988)-Acute Toxicity Identification Procedures formal development of sediment toxicity testing protocols. US EPA 2005-draft methods developed for sediment TIEs.

4 Brief History of Biomonitoring (con t) At the same time as the Toxicity Testing strategies, many researchers were using fish and macrobenthos surveys to determine environmental harm ( s). However it was difficult to tease out the observed environmental condition, cause and effect (1980s- 2000s). This is when we switched to end-of of-pipe strategies almost exclusively. Yet, the challenge existed when an effluent was toxic, what does that mean in the stream and vice versa. Thus, we have come full circle and are now looking at watersheds again, but with better tools.

5 Industrial Plant Case Example Main facility built in Operations include 2 main manufacturing units, blending facilities, storage & shipping, utilities, maintenance, lab and WWTP operating 24/7 365 days/yr. Site produces benzyl chloride, benzyl phthalates, phosphate esters, various blends, and muriatic acid. This site is the only US producer of benzyl chloride. Site is 232 acres with 125 acres developed.

6 WWTP Major Treatment Steps ph Control Primary Clarification Equalization Aeration (Biomass) Final Clarification Tertiary Filtration Comingled effluent with Municipal WWTP Sampling and Discharge to River

7 Red dots indicate less than graphical value (i.e. LC50 <28.0 %) BLACK dots indicate greater than graphical value (i.e. LC50 >100%)

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9 Red dots indicate less than graphical value (i.e. LC50 <28.0 %) BLACK dots indicate greater than graphical value (i.e. LC50 >100%)

10 Toxicity Identification Evaluation Six TIEs using full Phase I TIE assessments performed over a three year period. o No reduction in toxicity by ph adjustment, filtration, aeration, EDTA, thiosulfate, C18 on five of the samples. o One TIE did suggest ammonia (conclusion-due to overfeeding of the WWTP as a chemical addition). Study yp performed for determination of ion input. Dilution modeling/outfall diffuser design o Currently a single port outfall o Acute dilution (ZID) is 7 percent effluent o Chronic dilution (MZ) is 1.5 percent effluent

11 WWTP Total Dissolved Solids Salt Balance BZPH Phos Ester BZCL 69% of NaCl 23% of NaCl 8% of NaCl 26% of Flow 52% of Flow 22% of Flow WWTP To River

12 Pretreatment Considerations to Reduce TDS Projected concentration target to achieve C. dubia compliance salinity under 2000 ppm (2 ppt). All major process streams must be treated to achieve concentration target. Would require three salt removal units with associated solids handling. Resulting solids removed would contain organic residuals. Solids disposal costs higher due to organic residuals.

13 WWTP TDS Reduction Capital cost for centralized RO unit salt removal is estimated to be $38.4 M. Annual operating expense for the above is estimated to be $13.7 M. Several smaller units are expected to result in higher cost vs. central system. Overall environment impact of salt removal increased greenhouse gas by 86 tons/yr. CO 2 equivalent due to RO electricity and disposal transportation.

14 Cumulative Effects Physical Chemical Biological

15 Delaware River- Proximity of Discharge Salinity ranges from ppt as Salinity; classified as <1 ppt. State Division of Fish and Wildlife surveyed the river in 2000 and o 43% of species were associated with estuarine and/or marine habitats. o All species found are common species found in the coastal plains region. Effluent is discharged at edge of the dredged navigation channel.

16 Total Dissolved Solids (TDS) 95% of the toxicants in facility s discharge are sodium chloride. 5% of the toxicants are other salts (e.g., magnesium chloride, calcium chloride). As part of SETAC s WET Steering Committee; a blue ribbon panel made key determinations and recommendations regarding TDS which were published in ET&C (Goodfellow et al 2000), Major Ion Toxicity it in Effluents: A Review with Permitting Recommendations.

17 Changing Paradigm-Changing Strategy? We are pushing many of our discussions i as being more and more sustainable. However, in this case when you only monitor as an end-of of-pipe pp strategy it is toxic. The effluent discharge is sodium chloride discharged to the beginning of the estuary. No observed biological effects in the river. Removal of the salts from the effluent requires extensive capital and high energy requirements. Removal of salts also raise a transportation and disposal issue. Finally, does it make sense spending the effort to remove sodium chloride in a system that 2 river miles down stream is an estuary.

18 Watershed Case Example Watershed that is best characterized as urban and agricultural. Direct industrial dischargers, with IC25s ranging from >100-<10% effluent. Most discharges in northern reaches of watershed. Sediment has high concentrations of detected metals (arsenic, silver, cadmium, chromium, copper, lead, mercury, nickel, zinc as well as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs).

19 Watershed Case Example (con t) Habitat is also severely degraded. Sdi Sediment toxicity iit ranged from non-toxic to 100% mortality for samples. Most toxic samples were in the northern part of watershed. Samples evaluated in (Burton 1995), three locations in 2007 (MWRDGC 2007), and all locations again in Regulatory agencies were claiming that the system had improved considerably. Industry and MWRDGC felt that it had not.

20 Weight of Evidence Considerations We evaluated the spatial correlation or sediment concentrations to toxicity and watershed ecology Temporal correlation was attempted by season assessment Strength of effect evaluated Association at multiple sites Field and/or laboratory exposures Likelihood of stressor-effect effect linkage Specificity of the contamination

21 Items to be Considered as part of Weight of Eid Evidence Approaches Sediment Chemistry and Grain Size Benthic invertebrate community structure Sediment Toxicity Invertebrate body burdens or biomagnification

22 Metal Concentrations vs. Sediment Quality Criteria

23 PCB and PAH Concentration vs. Sediment Quality Criteria

24 Conclusions of the Assessment For the detected dt td metals, tl the majority concentrations ti from the 2008 samples were either higher or with in a factor of two or less. Was some improvement in the PAHs and PCB concentrations from to Habitat was impacted due to land use and storm water issues. When the entire watershed is evaluated in total, the system has not substantially improved with regards to sediment quality and habitat has degraded. New stressor in the system, heavy nutrient load- increased aquatic vegetation ti and duckweed d population.

25 In Summary Historically Hit i we took a holistic hliti approach to solving li water quality issue (ecological system level). However we didn t d have the tools to tease out the stressor and develop management strategies (prior to 1980s). In the 1980s 2000s we used end-of-pipe pp strategies for water quality management. However, this lead to many instances were end-of-pipe limits did not provide meaningful improvements to the entire watershed. Tools now exist to look at watersheds using cumulative effect strategies, evaluating water quality, ecological health, and habitat quality to evaluate how to improve watershed conditions most cost effectively. This is the new Paradigm.

26 Thank you. Are there any questions?