Presentation on theme: "Microconstituents – Emerging Contaminants Joint Water Resources Symposium New York Water Environment Associations New York Section American Water Works."— Presentation transcript:
Microconstituents – Emerging Contaminants Joint Water Resources Symposium New York Water Environment Associations New York Section American Water Works Association In Honor or Edwin C. Tifft, Jr. Syracuse, NY November 14, 2007 Joseph G. Cleary, P.E., BCEE Principal HydroQual, Inc. Mahwah, NJ
Presentation Outline WEFs Community of Practice Activities Microconstituents - Whats Included? Terminology / Name Changes / Key Messages Treatment Technologies Approach to Develop Best Solution Case Studies Summary
Why are Microconstituents a Concern? Better analytical methods and more monitoring are finding them in numerous receiving waters Feminized fish discovered in Europe in mid 1990s Steroids are implicated in Europe in late 1990s Treatment studies on POTWs (2002-2003) show POTWs are a collection point and one source to receiving waters USGS study of 139 streams in 2002 detected pharmaceuticals in 80% of samples More media coverage & public awareness and concerns.
WEF Community of Practice (CoP) Began at WEFTEC 2005 in Washington DC Deals with hot topics Broad, diverse membership – a benefit and challenge 150 Members and growing
WEF Key Messages Committed to sharing clear, factual information Advancing understanding Pursuing sound, sustainable solutions Focusing on source control
Two Fundamental Challenges 1. Technical challenges due to scientific uncertainties 2. Communication challenges related to public fears and perceptions.
Identified work products Technical Practice Updates Public & Press Communications Glossary of Terms Name for the issue WEF Community of Practice (CoP)
WEFs Public Communications Role Staff Products include: Key Messages Fact Sheets Illustrations Finding Expert Spokespersons Building Consensus
What to call the compounds without negatively branding them as a worry or concern? Media accounts and technical publications already using a multiplicity of terms Varying Communication Challenges Include:
Scientists wanting to communicate with precision to scientists WEF needs also to communicate with the scientific community, its membership and the general public The required vernacular must vary to suit the audience – so the language must be tailored Varying Communication Challenges Include:
Second challenge - Technical and communications experts Different audiences Different vocabulary Different approaches Communication Challenge
Why are Microconstituents a Concern? A review by the World Health Organization has concluded that low-level environmental exposure to Endocrine Disruptors has not yet been demonstrated to cause harm to human health (Damstra et al., 2002). Uptake of Endocrine Disruptors by humans from treated drinking water is relatively low in comparison to other sources such as food (GWRC, 2003).
Nov 2005 Endocrine Disrupting Compounds (EDC) (goal was communicating with WEF membership) Feb 2006 Compounds of Emerging Concern (CEC) (because not just about endocrine issues) Oct 2006 Compounds of Potential Concern (how to respond to the public – diligence in studying the issue) WEF Terminology Challenges
May 2007 More discussion about alarming the public – when we dont have a basis to ring the alarm bells Micro-constituents No, not little voters but really small things in the water environment that we can now detect (at ppb and ppt) and we dont know enough about. Terminology Challenge
These compounds are referred to in a multiplicity of ways including micro-constituents, trace constituents compounds of emerging concern, etc. WEF is calling them micro-constituents. We continue to study them as a prudent, conservative course of action reflecting our commitment to continue to assess the potential impact on human health and the environment. WEF Key Messages
Low levels of compounds remain but in concentrations that we believe are safe to return to the environment There are differing levels of Wastewater Treatment and Water Treatment We are studying the issue of even the trace amounts of these chemicals that remain after wastewater treatment WEF Key Messages
Treated wastewater is not the only pathway for these substances to enter the environment Many items we can detect have beneficial effects (i.e. medicines and pest control) Some improvement quality & longevity of life
Effects depend on: - Nature of compound - Type of exposure - Concentration - Quantity/duration of exposure WEF Key Messages
Some Facts to Keep in Mind Some compounds are naturally occurring Society chooses to ingest, bathe in and apply constituents at much higher concentrations than ever found in the environment
Physical/Chemical Properties – Keys to Treatment Water Solubility (mg/L) Henrys Constant (atm m 3 /mole) Octonal Water Coefficient Log Kow (Partitioning to Solids) Vapor Pressure, Vp Distribution Coefficient, Kd Biotransformation Ratio (K bio in soil, water, sludge and sediment) Biodegradability Photolysis Rate Oxidation Rate Reduction Rate Reference: Williams, 2006
Summary of Poseidon Project in Europe (Thomas Ternes) PPCPs and Estrogens removal focus in Europe Membranes & Ozonation in combination with Activated Sludge & Biofilters were evaluated Sludge treatment and urine separation was evaluated Sorption is an important mechanism for hydrophobic and positively charged compounds Biodegradation is a key mechanism Stripping was not effective Chemical oxidation was an effective polishing step for some PPCPs Some PPCPs are degraded in anaerobic sludge digestion Available process models can be used using rate coefficients developed
Activated Sludge Aeration Tank #1 Aeration Tank #2 Clarifier EQ Tank Denitrification Selector Filter Press Return Activated Sludge Waste Activated Sludge Effluent Process Wastewater Jet Aeration
Other Treatment Studies MLE Plant in San Diego (WERF Study, Oppenheimer, 2005) Six full-scale WWTPs in the U.S. and two pilot scale MBRs (WERF Study, Oppenheimer, 2006) Half of the 20 PPCPs were removed to greater than 80% at SRT <5 days No additional removal was attributed to MBR, media filters or longer HRTs Removal of musk fragrances required SRTs of at least 25 days
Results from Two-Stage MBR & Ozone Treatment in Pilot Study (1)APIs concentrations are listed in g/L (2)DL: Detection limit (3)ND: Not detected Reference: Helmig, Edward et al., WEFTEC 2005
WEF Technical Practice Update on Treatment EDC Committee Formed @ WEFTEC October 2005 List of TPUs was developed ( 13 topics) Treatment was done first Draft for comment in January 2006 Review meeting in February 2006 Committee name changed to Contaminants of Emerging Concern now Microconstituents Comments received in March 2006 on Treatment White Paper – Change to Technical Practice Update Final draft April 2007 Final version now on WEF website along with others
What Has Been Done and What Do We Know Many studies have demonstrated that activated sludge processes have the potential to remove a large fraction of several suspected EDCs, often to below detection limits (Ying, 2002). Johnson and Darton (2003) state that the EDCs generally implicated in endocrine disruption in fish – the estrogens E1, E2, EE2, and NP – are all inherently biodegradable
What Has Been Done and What Do We Know (continued) Siegrist estimates that about a 10 to 15 day SRT would be required for appreciable EDC removal (Siegrist et al., 2005). Estrogens can be eliminated in WWTPs by applying a nitrification/denitrification step (SRTs 15 days), or by effluent ozonation, nanofiltraton, or activated carbon. Anaerobic sludge digestion leads to a degradation of some PPCPs.
What Has Been Done and What Do We Know (continued) Substances that are difficult to biodegrade may be oxidized by AOPs, and the oxidized byproducts may be more amenable to biodegradation (Ried and Mielcke, 2003). Advanced oxidation process (AOP) are combinations of UV plus hydrogen peroxide, ozone plus hydrogen peroxide, and UV plus ozone, that are specifically designed to increase the formation of powerful hydroxyl radicals to oxidize EDCs and provide disinfection. Ozone shows similar potential to the AOPs for EDC removal.
What Has Been Done and What Do We Know (continued) 100% removal of EDCs from WWTP effluent will not be possible, so the goal should be reduction to levels with no adverse environmental effects. Source control (e.g., ecolabelling) and source separation (e.g., urine or rain water segregation) are important measures for reducing the PPCP load entering the environment.
What is Needed or Not Known? Toxicological and other environmental impacts are not known for most EDCs. Risk assessment studies are needed to develop appropriate regulatory actions (Schoenberg, Helmig et al., 2005). Fate studies are needed describing removals of compounds and pathways: biodegradation/biotransformation, partitioning to solids, volatilization.
What is Needed or Not Known? (continued) Analytical procedures are needed to detect lower levels of estrogens and to distinguish between various forms. Research to better understand the performance of engineered and natural treatment systems for reduction of these compounds (Oppenheimer et al., 2005). The hazard potential of the byproducts formed through treatment with advanced oxidation requires additional investigation.
Integrated / Holistic Approach to Develop Best Solution
Industry STP Urban Water Cycle bank filtrate Waterworks Drinking water Irrigation (soil/aquifer) Run off infiltration groundwater
Secondary Wastewater Treatment Tertiary Wastewater Treatment Production Utilities Sludge Raw Water Supply Well Water Supply Water Reuse Brine Disposal To POTW End of Pipe Approach Integrated vs. End-of-Pipe Approach
Collaborative Team Approach is Best Mobilize a Team – Include People Closest to Problems and Stakeholders Include Production, Water and Wastewater Operations, Environmental Compliance Managers Outside Consultant Commitment of Management and Team Frequent Communications and Meetings
Flow Balance & Wastewater Characteristics Design Basis (flow & wasteloads) Screen Technologies Develop Initial Alternatives Alternative Comparison (cost & non-costs criteria) Narrow List of Alternatives Treatability Studies & Process Modeling Refine Comparison Select Best Solution Approach Sequence of Tasks
Case Study #1 Pharmaceutical Company in U.S. New Product from Europe – Chlorination (bleach) used for destruction Initial testing showed it was non-biodegradable, would pass through existing treatment plant and result in effluent toxicity violations. Treatability Studies were conducted to evaluate Advanced Oxidation treatment technology; UV/hydrogen peroxide, catalyst/UV/hydrogen peroxide, UV/ozone and UV/hydrogen peroxide/ozone. Two technologies also reduced effluent toxicity by 95% (UV/ozone and UV/ozone/hydrogen peroxide. Product was never brought to the plant from Europe.
Case Study #2 Pharmaceutical Company in Puerto Rico New Product Active Pharmaceutical Ingredients (API) in cleaning wastewaters Company had Corporate Guidelines (from Europe) for discharge to the Atlantic Ocean Discharge through POTW to Atlantic Ocean Best solution was holding tank with controlled release to POTW – no treatment was needed
Case Study #3 Pharmaceutical Company in Ireland. Considering production of an antifungal compound. Compound is relatively insoluble and non-biodegradable. Potential to accumulate in sludge and impact composting. Concern was potential impact on activated sludge plant and sludge composting at POTW. Treatability Studies simulated activated sludge and sludge composting to determine process impacts and concentrations present in sludge and compost material. There was no impact on activated sludge performance including nitrification. Mass balance showed 70% of compound was biodegradable. There was no impact on composting process.
SUMMARY Microconstituents are now being detected more in water and wastewater. Analytical methods are specialized. Information is developing on treatment/destruction of Microconstituents in both POTWs and pharmaceutical wastewaters. Applicable treatment technologies include biological and advanced oxidation processes. EDCs removal in POTWs and Industrial Wastewater Plants varies based on wastewater characteristics and process design operating parameters such as sludge age. Treatability studies are very helpful for site-specific wastewater projects. Stay tuned as more Technical Practice Updates are developed by WEF and specially conferences are planned.