2009 Puget Sound Georgia Basin Ecosystem Conference

Transcription

1 2009 Puget Sound Georgia Basin Ecosystem Conference Session Time/Date: 3:30 pm 5:00 pm, Monday, February 09, 2009 Session Title: Wastewaters in the Salish Sea: From Science to Solutions Session Chairs: Eric Knudsen Contributors: Impacts of Wastewater on the Salish Sea Andrea Copping, Pacific Northwest National Laboratory The Salish Sea watershed is home to approximately seven million people. Waste water is defined as end of pipe discharges. Non point sources of waste water are not considered in this presentation. The largest freshwater input into the Salish Sea is the Fraser River. Constituents of wastewater are: micro organisms, toxic chemicals, emerging chemicals of concern, nutrients, temperature, and salinity. Most wastewater contaminants are released as sediments. However, some are located in the surface micro layer or dissolved in water. Medium, concentration and location affect contaminant toxicity. Toxic chemicals can accumulate up the food chain. Toxicity depends on exposure route and concentration, susceptibility of the living system, and location of the sequestered toxin (i.e. fat tissue, liver). Nutrients include nitrogen species, phosphate and silicate. Enrichment of nutrients can lead to noxious algae blooms, hypoxia and death of organisms, but only in localized areas of the Salish Sea with poor circulation. Wastewater outfalls discharge wastewater at depth and include diffusers. Best location for outfalls is into swift moving waters or ocean currents. People and wildlife are likely to be harmed by wastewater contaminants. Most outfalls are chlorinated to help manage micro organisms. Industrial pre treatment is used to treat water before it is discharged into the receiving environment. The greatest risk from wastewater likely come from toxic contaminants; stormwater may contribute more toxics however. Improved Estimates of Loading from dischargers of municipal and industrial wastewaters Kevin Fitzpatrick, Washington State Department of Ecology Conducted a Phase 2 study to refine understanding of wastewater loading pathways. Determined that toxic chemicals from wastewater dischargers were small relative to the total loading from all of the major loading sources to Puget Sound (including atmospheric deposition).

2 Study continues to support Phase I findings that stormwater runoff is the major contributing source of toxics to the Puget Sound. Current drivers for improving water quality and treatment and diversion strategies for managing wastewater David Clark, HDR The EPA has placed great emphasis on Puget Sound with regards to nitrogen nutrient standards. Under summer low flow conditions, WWTP inputs outweigh those from river sources into Puget Sound. Bozeman case study determined that 50% of nitrogen could be removed at no additional cost; removals were due to infrastructure investments. If the waste water technology used in Bozeman was implemented in Puget Sound, nitrogen loading would decrease by 50%+. However, the investments to do this are expensive. Point source discharges are not a great source of organic inputs into Puget Sound. Advanced waste water treatment costs more money and uses more energy than traditional methods. Patrick Roe, HDR A number of Puget Sound utilities have tried to increase water quality. During spring, summer and fall, nitrogen is removed from wastewater. The majority of flow is discharged to Budd Inlet. The goals of the Budd Inlet wastewater treatment plant improvement project were: to improve nitrogen removal; to improve sustainable practices and reduce operating costs; to increase flexibility to accommodate changing waster water characteristics; and to maximize the use of existing facilities on a constrained plant site. Treating waste as a resources: A tool to fight climate change Stephen Salter, Farallon Consultants, Inc. Our problems of scarce water and energy, food, and climate change are connected The solutions to these four issues are also connected, if we choose to redesign city infrastructure along the lines of nature's closed ecological cycles Nature has no wastes Wastewater can be treated to recover water, heat, biofuels, and fertilizer Water reclamation: o Outfalls are a waste of water. o Reclaimed water can be used for irrigation and other non potable purposes. o If we cycle water in a closed system, we can reduce demands on upstream sources.

3 When energy and fertilizers are recovered from wastewater, we can reduce in the receiving environment, and also reduce the pollution which is generated when we produce upstream energy and artificial fertilizer Can treat wastewater until it is potable again (not toilet to tap yet!) Wastewater can be used to heat or cool homes. To use the heating and cooling properties of wastewater, treatment plants must be co located with energy loads (users). Since wastewater is warmer than ground sources for heat pumps, which allows more heat to be recovered Minerals may be taken out of wastewaters to create fertilizers. Wastewater made, slow releasing fertilizer may replace traditional petroleum products. Biofuels may be produced from waste (e.g. biosolids from wastewater treatment, and kitchen waste from the community), displacing fossil fuels (i.e. biogas bus in Stockholm). We need to examine public policies at the municipal level: are we encouraging or discouraging the practices of resource recovery? Emerging Issues: Emerging chemicals of concerns include pharmaceuticals, endocrine disruptors, and cellular mimics. The enclosed nature of the Salish Sea means that some contaminates which come into this area never leave. More toxics coming into the Salish Sea from storm water than from wastewater or? Un sewered areas and wet weather driven combined sewer overflows cause concern for waste water treatment. Both nutrient removal and water reclamation are practical approaches to improve marine water quality. Harvest of algae may be one way to remove organics. Can biogases be used to replace petroleum products in transportation, heating, cooling, housing? Action types from Q & A session: Science, Monitoring and Research Q: Tony Paulson: How is the hydrodynamic fate (i.e. mixing zones) considered in determining water quality standards? A: Kevin Fitzpatrick: Mixing zone analysis helps to identify water quality standards. Standards must look at water components in both near and far fields. Q: Dave Peeler: How should the emerging bio and nano contaminants be treated in wastewater? What are their ecosystem impacts after treatment? A AC: Nano technology are emerging contaminants which are currently being researched. Impacts in fresh water, marine water and in sediments are only now being discovered.

4 Q: Dimitri: Can algae be used to clean water and be used as biogas? A AC: When organic material rots it robs the water of oxygen, If you remove the algae, theoretically you will prevent this, and you could use the algae as biofuel, though adequate supplies of algal biofuel need to come from certain species. Q Dimitri: How is flood water contamination addressed in a wastewater context, is it treated? A AC: Sewer overflows occur when there are high flood waters. Large volumes of storm water can result in water being flushed directly into the receiving environment. Storm water is not treated because it occurs episodically and results in huge amounts of water to treat; treatment centre can not hold this volume. A KF: It is difficult to store the flood water for treatment because of its high volume. A PR: King country has put large investments into storm water treatment. A DC: Not all communities are like King County so have not yet made investments into storm water control and treatment. Policy Changes Q: Lindie Schimdt: How should reclamation be framed as a wastewater option to decision makers? Usually its costs are prohibitive as compared to outfall options. A Salter: Need to look at heating, cooling, and energy infrastructure holistically in determining the true costs of a given development. Not just at outfall versus reclamation comparisons. Q: How should septic systems / un sewered areas be managed? A DC: There has been a lot of development with on site septic systems, and you have a valid concern. Nutrient loading from the septic systems is hard to quantify. Q: What are the risks to the public when recycled water is used to irrigate? Can pharmaceuticals leach into groundwater from recycled water use? Is there liability protection for managers who use recycled water publically? A Unknown: Recycled water has most of the contaminants removed from it once it is applied publically. ADC: The soil system is a complex system and can attenuate many effects arising from contamination. Education and Outreach Q: Monica Handleburn: Are there policies on how to dispose of personal care items, cleaners, etc? Citizens need to take responsibilities for their actions. A DC: Prescription drugs should not be flushed down the toilet. Disposal of pharmaceuticals is a large concern for wastewater managers. Q: Are there rebate programs for appropriate technology, such as composting toilets? This technology is used in Africa, why not here?

5 A: The utility gives rebates for composting toilets. However, these toilets have high maintenance issues and no one has ever taken a rebate