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San Diego faces a major decision on wastewater treatment and water recycling [update]

Posted by George J Janczyn on July 16, 2013

The story below was originally published April 24 but it seems timely to revive it in order to highlight a new report presented at San Diego’s Independent Rates Oversight Committee (IROC) yesterday (Monday July 15). The two handouts distributed at the meeting contain most of the information discussed and are provided here.

Preferably you’ll read the story first (if you missed it) and then the IROC meeting handouts. Otherwise just click the two images below to read the handouts:

 

JPAStrategy JPANarrative

 

______________________________

 

For more than a year San Diegans have been recipients of news media reports and a public outreach program explaining the city’s one-year Water Purification Demonstration Project (WPDP). Yesterday (Tuesday April 24), the City Council got the final report and discussed possible next steps. Local news media have yet to weigh in on this story, so here’s a start:

The goal of the WPDP was to determine the feasibility of taking recycled water and purifying it in a special advanced treatment facility located at the North City Water Reclamation Plant, sending the purified water through a pipeline to the San Vicente Reservoir where it would blend with imported water from the Colorado River and Northern California, and then be piped to the city’s Alvarado Water Treatment Plant for final purification and distribution to residents (in emergencies the water could go to other treatment plants but Alvarado would be the default). The process is sometimes referred to as Indirect Potable Reuse through Reservoir Augmentation, or IPR.

Click image to enlarge. Recycled water is produced by treating wastewater to a "tertiary" level after which it is used for irrigation and commercial/industrial applications. The IPR process takes some of the recycled "tertiary" water and puts it through an advanced purification process that renders it similar in quality to distilled water.

Recycled water is produced by treating wastewater to a “tertiary” level after which it is used for irrigation and commercial/industrial applications. The IPR process takes some of the recycled “tertiary” water and puts it through an advanced purification process that renders it similar in quality to distilled water.

 

The report “provides an overview of the technical studies, advanced water purification facility testing, and public education and outreach efforts conducted as part of the Water Purification Demonstration Project. It also presents findings that support the conclusion that a reservoir augmentation project at San Vicente Reservoir would be feasible.”

In short, IPR was shown to be technically sound and, if a recommended large-scale project is approved, would provide the city with about 15,000 acre-feet per year of safe, sustainable, reliable, locally sourced potable water.

A large-scale IPR program would also significantly reduce the amount of wastewater discharged into the ocean. And if a full-scale program works out well, the program could eventually be expanded to build additional satellite advanced purification facilities and recycle 90,000 acre-feet or more per year. That’s 90,000 acre feet less water lost to wastewater discharge.

The City Council enthusiastically accepted the report. Now it needs to decide whether to authorize a full-scale IPR program. That decision will have to wait until Public Utilities Department staff report back in 90 days to the Natural Resources & Culture Committee with a recommended preferred plan. The committee would then forward a recommendation to the full City Council.

The really big part of this story, though, is that San Diego’s wastewater management policy has been a problem for many years and it’s in that context that the potable reuse program needs to be understood.

The Point Loma Wastewater Treatment Plant

Point Loma outfall pipeline where it enters the Pacific.

Point Loma outfall pipeline where it enters the Pacific.

Google Maps view shows the underwater 4.5 mile outfall pipeline and diffuser

The underwater 4.5 mile outfall pipeline and the “Y” diffuser can be seen on this Google Maps image

Because of its arid climate and limited local resources, San Diego needs to import some 80% of its water from hundreds of miles upstream, mainly the Colorado River and northern California. Before San Diego gets its water, upstream municipalities consume some of that water, much of which turns into wastewater. They treat their wastewater and discharge it into the flow of water that continues to downstream communities, where the process is repeated. And repeated.

By the time imported water gets to San Diego, the imported water contains the discharge from some 300 upstream wastewater treatment plants. That should be thought-provoking enough, since San Diego’s water only gets treated in a standard water treatment plant, not an advanced purification facility as is being proposed.

Since there are no users downstream of San Diego, the city discharges its wastewater into the Pacific Ocean from the Point Loma Wastewater Treatment Plant, to the tune of roughly 175 million gallons each day. There’s a problem with that, and not just because so much water gets wasted by dumping it.

The federal Clean Water Act requires wastewater discharges to receive “secondary treatment,” and that’s what the upstream communities do. San Diego, however, does not. Instead it does what it calls “advanced primary” treatment.

Back in 1988, the EPA sued the city for failure to achieve secondary treatment. The city, however, felt that an upgrade to secondary would be unnecessarily and exceedingly expensive (likely more than $1.5 billion that ratepayers would have to fund) and that the parcel of land on which the Point Loma plant lies is so small that it was impossible to expand it.

Ultimately, the EPA agreed to give San Diego some leeway, but as mitigation the city had to develop a water recycling/reclamation program with a capacity of 45 million gallons per day (mgd) and monitor the “advanced primary” Point Loma effluent plume dispersed into the Pacific to ensure discharge quality would fall within specified limits.

The reduction in wastewater discharged from Point Loma along with ocean monitoring would be good for the environment, while recycling would provide more usable water for the city.

Thus was born the 30 mgd capacity North City Water Reclamation Plant (1997) and the 15 mgd capacity South Bay Water Reclamation Plant (2002), along with a “purple pipe” network to distribute recycled water treated at the “tertiary” level to large customers for irrigation and certain commercial/industrial uses.

But things didn’t work out as well as expected.

As reported by a Water Online news report:

In 1997, the San Diego Water Department raided its cash reserves of $65 million intended for fixing the city’s crumbling drinking water system. It used that money to lay 46 miles of purple pipeline to customers in Mira Mesa, Torrey Pines, Scripps Ranch and University City.

Recycled water has turned out to be a big bust. It cannot be sent through existing water lines, it requires expensive construction of new pipelines (“purple pipe”) to distribute the water to customers. Then the customers have to retrofit their existing plumbing or irrigation system with parallel purple pipe systems. The city spent over $18 million to assist customers with that expense. A retrofit of Miramar Nurseries, for instance, cost the city $300,000, according to Hossein Juybari, the city’s recycled water coordinator. The golf course at Miramar Marine Corps Air Station is being replumbed at a cost of $700,000 to the city. The EPA figured the city could reuse 25 percent of the flows of the North City plant by the end of 2003, a goal it set when it granted the city $70 million toward construction. Currently, the city is reusing less than 17 percent of the sewage processed at North City, and water officials say they have no hope of reaching 25 percent anytime soon. By 2010, the EPA goal for the city becomes 50 percent.

[The City has not responded to my request for comment on the veracity of this report]

Another setback to recycling occurred with this 1999 City Resolution ordering the City Manager not to spend money on “water repurification.”

Meanwhile, the City received another EPA waiver for Point Loma in 2001 and lawsuits were filed by San Diego Coastkeeper, the San Diego chapter of the Surfrider Foundation, and the San Diego chapter of the Sierra Club. That history is documented in a memo written by Marco Gonzalez from the Coast Law Group.

According to Gonzalez, there were 3 points to address:

  • Issuance of the waiver in the proposed form violated federal CWA [Clean Water Act] anti-degradation and anti-backsliding regulations.

  • Failure by the City to achieve 45 million gallons per day (MGD) of sewage reclamation was a violation of OPRA [Ocean Pollution Reduction Act], and that merely constructing reclamation capacity without implementing beneficial reuse was insufficient.

  • The plume outfall [from Point Loma] monitoring program was not sufficient to accurately characterize plume migration and impacts.

(Gonzalez’s memo goes into considerable detail about the negotiations and events during that period. It is a fascinating read, posted here with his permission.)

The outcome of these negotiations brought about the following:

1. Acknowledging that the Point Loma wastewater plant lacked sufficient space for expansion, the groups proposed, and the city agreed, to conduct a pilot study of one of the more promising technologies – called Biologically Aerated Filtration (BAF) – to see if it could achieve secondary standards given the quality of Point Loma’s sewage influent and flow demands.

2. A monitoring program by an independent team of technical experts from the Scripps Institution of Oceanography would be assembled to determine the effectiveness of Point Loma’s “advanced primary” treatment.

3. The City would further consider advanced treatment of its reclaimed water for comingling with imported water supplies in drinking water reservoirs [i.e., indirect potable reuse].

Point #3 above resulted in the 2005 Water Reuse Study intended to look at how we might maximize the use of reclamation capacity then existing at North City and South Bay. Following this study, the decision was made to pursue the IPR Demonstration Project. During this same period, a coalition of environmental, business, labor, and trade groups formed the “IPR Coalition” to advance the cause.

______________________________

Years passed as these issues were hashed out. A stronger ocean monitoring program was developed, but the capacity of the two reclamation plants remains underutilized.

At the end of 2008, the City Council overrode a mayoral veto and authorized the raising of funds to pay for the IPR demonstration project (which later got the name Water Purification Demonstration Project).

In 2009, the city needed to apply for a new 5-year EPA waiver, the environmental groups opposed it and promised lawsuits, but Marco Gonzalez and Bruce Reznik offered the City a “non-opposition” to the waiver (very different from “support”) in exchange for the much more in-depth water reuse study considering the possibility of maximizing reclamation and minimizing discharge to the ocean.

With this agreement in place, the city was able to get another waiver. But the EPA and California Coastal Commission warned the city that future waiver requests would not be looked upon favorably.

However, as Mr. Gonzalez wrote in his memo, “the light bulb went off:”

“The goal of the Clean Water Act is not simply to ensure compliance with water quality standards and to achieve the cleanest runoff mandated by federal or state laws. Rather, the structure and purpose of the CWA is geared toward minimizing and when possible eliminating discharges altogether [emphasis added]. Given the value of water in San Diego (at the end of the Colorado River and State Water Project pipelines), the likelihood of continued drought, the technological gains in reverse osmosis, the relatively dirty source water entering our reservoirs, the political and public acceptance for desalination, and a host of other political, economic, and social factors, there is no way San Diego can sustain its current paradigm of pushing sewage down to Point Loma and off into the Pacific Ocean…. Looking at the current paradigm of water supply and sewage conveyance/treatment, the ONLY sustainable option is IPR. With this perspective, our goal became clear. We want to eliminate all discharges to the ocean and maximize IPR as soon as economically, technically, and politically feasible.”

The IPR Coalition, now named the Water Reliability Coalition, continues its work to this day (for some reason the website appears to have been hijacked but they’ve been notified).

Next steps

The clock is ticking for the Point Loma plant. Under the current waiver, the city is already on notice that future waiver requests will not be looked on favorably. Last October, the California Coastal Commission sent a letter to the City expressing “significant concern that the City has not yet committed to milestones and implementation schedules that would enable the City to end the pursuit of future secondary treatment waivers.”

If the city doesn’t demonstrate substantial progress, a new Point Loma waiver might not be easily won and the city could face fines, penalties, and lawsuits as a consequence. The waiver expires July 31, 2015; a renewal application will have to be made in 2014. I’ve learned the Public Utilities Department Director Roger Bailey is now leading a Point Loma waiver strategy team but haven’t been able to obtain more information about it.

San Vicente reservoir before the dam raise project

San Vicente reservoir before the dam raise project

The heightened San Vicente Dam increases the reservoir capacity from 90,000 acre-feet to 242,000 acre-feet.

The heightened San Vicente Dam increases the reservoir capacity from 90,000 acre-feet to 242,000 acre-feet.

The City Council’s acceptance of the IPR project report is certainly progress. But in accepting the report, several City Council members indicated a desire to also explore Direct Potable Reuse, or DPR as a less expensive alternative to IPR. Whereas the IPR proposal involves construction of an expensive pipeline to the San Vicente Reservoir (which, incidentally, has been vastly expanded), DPR would send the water directly to the potable water treatment plant (likely Alvarado), using a much shorter pipeline, with no detention time in a reservoir. That could save more than $200 million in pipeline construction, but also raises questions about safety and regulatory approval.

So much time, effort, and expense has gone into clearing regulatory hurdles for the IPR project, that DPR, for all its attractiveness, could be a distraction from work that is still needed for IPR. The California Department of Public Health (CDPH) and the San Diego Water Board have indicated general acceptance of San Diego’s IPR project, but it is many years away from regulatory approval for DPR. Senate Bill 918 requires CDPH to investigate the feasibility of developing uniform water recycling criteria for direct potable reuse and to provide a final report on that investigation to the legislature by December 31, 2016. The regulations will come some years after that.

One option could be to proceed with a large scale IPR program with a pipeline to San Vicente as already envisioned. Subsequently, satellite advanced treatment plants could be built for DPR. That would allow San Diego’s waiver application to say we’re making substantial progress. It would also allow time for CDPH to issue regulations for DPR…it seems likely that won’t happen for many years beyond 2016.

Assuming the preferred path is IPR now and DPR in the future, the issue is still how to get things moving? What questions need to be addressed?

At the City Council meeting, PUD’s Marsi Steirer said the cost of IPR would not only be lower than the cost of desalination, it would be cheaper than imported water (around $1,000 per acre foot). That’s competitive with the price of imported water, but according to the Project report the actual cost is about $2,000 per acre foot—around where desalination is priced. Reading from the report:

“If full-scale reservoir augmentation is implemented, the city would not need to build a 7 million gallon wet weather storage facility to attentuate wastewater flow to Point Loma; reduced overall flow to Point Loma would reduce annual operations and maintenance costs at Point Loma plant and Pump Station 2 which conveys flows to Point Loma. Water salinity in the city water supply would be lower, potentially reducing costs further. Taking these factors into account PUD estimates the NET cost for IPR would be about $1,000 per acre foot.”

But wastewater has to be treated at Point Loma or at the North City reclamation plant, so are the savings really that great or is the cost just being shifted from Point Loma processing to North City processing? It will be interesting to see if the sewage treatment portion of our water bill shows a price decrease. So, next steps would appear to be:

  • IPR would benefit both water and wastewater systems, therefore proportional share of costs needs to be determined in order to prepare water and wastewater rate cases

  • Determine a contracting mode

  • Refine pipeline alignment, which represents an estimated 60% of total implementation cost

  • Coordinate with regional wastewater and reuse objectives including Point Loma waiver expiration in 2015

  • Monitor development of DPR regulations

In any event, it doesn’t seem wise to argue that we should embark on IPR because it is cheaper. It may or may not be less expensive than desalination or imported water in the long run, but IPR is clearly the right thing to do.

______________________________

I welcome any comments that can correct and improve on this report.

Some sources for this story that may be of interest:

 

Posted in Water, Water Purification Demonstration Project | Tagged: , | Leave a Comment »

San Diego faces a major decision on wastewater treatment and water

Posted by George J Janczyn on April 24, 2013

For more than a year San Diegans have been recipients of news media reports and a public outreach program explaining the city’s one-year Water Purification Demonstration Project (WPDP). Yesterday (Tuesday April 24), the City Council got the final report and discussed possible next steps. Local news media have yet to weigh in on this story, so here’s a start:

The goal of the WPDP was to determine the feasibility of taking recycled water and purifying it in a special advanced treatment facility located at the North City Water Reclamation Plant, sending the purified water through a pipeline to the San Vicente Reservoir where it would blend with imported water from the Colorado River and Northern California, and then be piped to the city’s Alvarado Water Treatment Plant for final purification and distribution to residents (in emergencies the water could go to other treatment plants but Alvarado would be the default). The process is sometimes referred to as Indirect Potable Reuse through Reservoir Augmentation, or IPR.

Click image to enlarge. Recycled water is produced by treating wastewater to a "tertiary" level after which it is used for irrigation and commercial/industrial applications. The IPR process takes some of the recycled "tertiary" water and puts it through an advanced purification process that renders it similar in quality to distilled water.

Recycled water is produced by treating wastewater to a “tertiary” level after which it is used for irrigation and commercial/industrial applications. The IPR process takes some of the recycled “tertiary” water and puts it through an advanced purification process that renders it similar in quality to distilled water.

 

The report “provides an overview of the technical studies, advanced water purification facility testing, and public education and outreach efforts conducted as part of the Water Purification Demonstration Project. It also presents findings that support the conclusion that a reservoir augmentation project at San Vicente Reservoir would be feasible.”

In short, IPR was shown to be technically sound and, if a recommended large-scale project is approved, would provide the city with about 15,000 acre-feet per year of safe, sustainable, reliable, locally sourced potable water.

A large-scale IPR program would also significantly reduce the amount of wastewater discharged into the ocean. And if a full-scale program works out well, the program could eventually be expanded to build additional satellite advanced purification facilities and recycle 90,000 acre-feet or more per year. That’s 90,000 acre feet less water lost to wastewater discharge.

The City Council enthusiastically accepted the report. Now it needs to decide whether to authorize a full-scale IPR program. That decision will have to wait until Public Utilities Department staff report back in 90 days to the Natural Resources & Culture Committee with a recommended preferred plan. The committee would then forward a recommendation to the full City Council.

The really big part of this story, though, is that San Diego’s wastewater management policy has been a problem for many years and it’s in that context that the potable reuse program needs to be understood.

The Point Loma Wastewater Treatment Plant

Point Loma outfall pipeline where it enters the Pacific.

Point Loma outfall pipeline where it enters the Pacific.

Google Maps view shows the underwater 4.5 mile outfall pipeline and diffuser

The underwater 4.5 mile outfall pipeline and the “Y” diffuser can be seen on this Google Maps image

Because of its arid climate and limited local resources, San Diego needs to import some 80% of its water from hundreds of miles upstream, mainly the Colorado River and northern California. Before San Diego gets its water, upstream municipalities consume some of that water, much of which turns into wastewater. They treat their wastewater and discharge it into the flow of water that continues to downstream communities, where the process is repeated. And repeated.

By the time imported water gets to San Diego, the imported water contains the discharge from some 300 upstream wastewater treatment plants. That should be thought-provoking enough, since San Diego’s water only gets treated in a standard water treatment plant, not an advanced purification facility as is being proposed.

Since there are no users downstream of San Diego, the city discharges its wastewater into the Pacific Ocean from the Point Loma Wastewater Treatment Plant, to the tune of roughly 175 million gallons each day. There’s a problem with that, and not just because so much water gets wasted by dumping it.

The federal Clean Water Act requires wastewater discharges to receive “secondary treatment,” and that’s what the upstream communities do. San Diego, however, does not. Instead it does what it calls “advanced primary” treatment.

Back in 1988, the EPA sued the city for failure to achieve secondary treatment. The city, however, felt that an upgrade to secondary would be unnecessarily and exceedingly expensive (likely more than $1.5 billion that ratepayers would have to fund) and that the parcel of land on which the Point Loma plant lies is so small that it was impossible to expand it.

Ultimately, the EPA agreed to give San Diego some leeway, but as mitigation the city had to develop a water recycling/reclamation program with a capacity of 45 million gallons per day (mgd) and monitor the “advanced primary” Point Loma effluent plume dispersed into the Pacific to ensure discharge quality would fall within specified limits.

The reduction in wastewater discharged from Point Loma along with ocean monitoring would be good for the environment, while recycling would provide more usable water for the city.

Thus was born the 30 mgd capacity North City Water Reclamation Plant (1997) and the 15 mgd capacity South Bay Water Reclamation Plant (2002), along with a “purple pipe” network to distribute recycled water treated at the “tertiary” level to large customers for irrigation and certain commercial/industrial uses.

But things didn’t work out as well as expected.

As reported by a Water Online news report:

In 1997, the San Diego Water Department raided its cash reserves of $65 million intended for fixing the city’s crumbling drinking water system. It used that money to lay 46 miles of purple pipeline to customers in Mira Mesa, Torrey Pines, Scripps Ranch and University City.

Recycled water has turned out to be a big bust. It cannot be sent through existing water lines, it requires expensive construction of new pipelines (“purple pipe”) to distribute the water to customers. Then the customers have to retrofit their existing plumbing or irrigation system with parallel purple pipe systems. The city spent over $18 million to assist customers with that expense. A retrofit of Miramar Nurseries, for instance, cost the city $300,000, according to Hossein Juybari, the city’s recycled water coordinator. The golf course at Miramar Marine Corps Air Station is being replumbed at a cost of $700,000 to the city. The EPA figured the city could reuse 25 percent of the flows of the North City plant by the end of 2003, a goal it set when it granted the city $70 million toward construction. Currently, the city is reusing less than 17 percent of the sewage processed at North City, and water officials say they have no hope of reaching 25 percent anytime soon. By 2010, the EPA goal for the city becomes 50 percent.

[The City has not responded to my request for comment on the veracity of this report]

Another setback to recycling occurred with this 1999 City Resolution ordering the City Manager not to spend money on “water repurification.”

Meanwhile, the City received another EPA waiver for Point Loma in 2001 and lawsuits were filed by San Diego Coastkeeper, the San Diego chapter of the Surfrider Foundation, and the San Diego chapter of the Sierra Club. That history is documented in a memo written by Marco Gonzalez from the Coast Law Group.

According to Gonzalez, there were 3 points to address:

  • Issuance of the waiver in the proposed form violated federal CWA [Clean Water Act] anti-degradation and anti-backsliding regulations.

  • Failure by the City to achieve 45 million gallons per day (MGD) of sewage reclamation was a violation of OPRA [Ocean Pollution Reduction Act], and that merely constructing reclamation capacity without implementing beneficial reuse was insufficient.

  • The plume outfall [from Point Loma] monitoring program was not sufficient to accurately characterize plume migration and impacts.

(Gonzalez’s memo goes into considerable detail about the negotiations and events during that period. It is a fascinating read, posted here with his permission.)

The outcome of these negotiations brought about the following:

1. Acknowledging that the Point Loma wastewater plant lacked sufficient space for expansion, the groups proposed, and the city agreed, to conduct a pilot study of one of the more promising technologies – called Biologically Aerated Filtration (BAF) – to see if it could achieve secondary standards given the quality of Point Loma’s sewage influent and flow demands.

2. A monitoring program by an independent team of technical experts from the Scripps Institution of Oceanography would be assembled to determine the effectiveness of Point Loma’s “advanced primary” treatment.

3. The City would further consider advanced treatment of its reclaimed water for comingling with imported water supplies in drinking water reservoirs [i.e., indirect potable reuse].

Point #3 above resulted in the 2005 Water Reuse Study intended to look at how we might maximize the use of reclamation capacity then existing at North City and South Bay. Following this study, the decision was made to pursue the IPR Demonstration Project. During this same period, a coalition of environmental, business, labor, and trade groups formed the “IPR Coalition” to advance the cause.

______________________________

Years passed as these issues were hashed out. A stronger ocean monitoring program was developed, but the capacity of the two reclamation plants remains underutilized.

At the end of 2008, the City Council overrode a mayoral veto and authorized the raising of funds to pay for the IPR demonstration project (which later got the name Water Purification Demonstration Project).

In 2009, the city needed to apply for a new 5-year EPA waiver, the environmental groups opposed it and promised lawsuits, but Marco Gonzalez and Bruce Reznik offered the City a “non-opposition” to the waiver (very different from “support”) in exchange for the much more in-depth water reuse study considering the possibility of maximizing reclamation and minimizing discharge to the ocean.

With this agreement in place, the city was able to get another waiver. But the EPA and California Coastal Commission warned the city that future waiver requests would not be looked upon favorably.

However, as Mr. Gonzalez wrote in his memo, “the light bulb went off:”

“The goal of the Clean Water Act is not simply to ensure compliance with water quality standards and to achieve the cleanest runoff mandated by federal or state laws. Rather, the structure and purpose of the CWA is geared toward minimizing and when possible eliminating discharges altogether [emphasis added]. Given the value of water in San Diego (at the end of the Colorado River and State Water Project pipelines), the likelihood of continued drought, the technological gains in reverse osmosis, the relatively dirty source water entering our reservoirs, the political and public acceptance for desalination, and a host of other political, economic, and social factors, there is no way San Diego can sustain its current paradigm of pushing sewage down to Point Loma and off into the Pacific Ocean…. Looking at the current paradigm of water supply and sewage conveyance/treatment, the ONLY sustainable option is IPR. With this perspective, our goal became clear. We want to eliminate all discharges to the ocean and maximize IPR as soon as economically, technically, and politically feasible.”

The IPR Coalition, now named the Water Reliability Coalition, continues its work to this day (for some reason the website appears to have been hijacked but they’ve been notified).

Next steps

The clock is ticking for the Point Loma plant. Under the current waiver, the city is already on notice that future waiver requests will not be looked on favorably. Last October, the California Coastal Commission sent a letter to the City expressing “significant concern that the City has not yet committed to milestones and implementation schedules that would enable the City to end the pursuit of future secondary treatment waivers.”

If the city doesn’t demonstrate substantial progress, a new Point Loma waiver might not be easily won and the city could face fines, penalties, and lawsuits as a consequence. The waiver expires July 31, 2015; a renewal application will have to be made in 2014. I’ve learned the Public Utilities Department Director Roger Bailey is now leading a Point Loma waiver strategy team but haven’t been able to obtain more information about it.

San Vicente reservoir before the dam raise project

San Vicente reservoir before the dam raise project

The heightened San Vicente Dam increases the reservoir capacity from 90,000 acre-feet to 242,000 acre-feet.

The heightened San Vicente Dam increases the reservoir capacity from 90,000 acre-feet to 242,000 acre-feet.

The City Council’s acceptance of the IPR project report is certainly progress. But in accepting the report, several City Council members indicated a desire to also explore Direct Potable Reuse, or DPR as a less expensive alternative to IPR. Whereas the IPR proposal involves construction of an expensive pipeline to the San Vicente Reservoir (which, incidentally, has been vastly expanded), DPR would send the water directly to the potable water treatment plant (likely Alvarado), using a much shorter pipeline, with no detention time in a reservoir. That could save more than $200 million in pipeline construction, but also raises questions about safety and regulatory approval.

So much time, effort, and expense has gone into clearing regulatory hurdles for the IPR project, that DPR, for all its attractiveness, could be a distraction from work that is still needed for IPR. The California Department of Public Health (CDPH) and the San Diego Water Board have indicated general acceptance of San Diego’s IPR project, but it is many years away from regulatory approval for DPR. Senate Bill 918 requires CDPH to investigate the feasibility of developing uniform water recycling criteria for direct potable reuse and to provide a final report on that investigation to the legislature by December 31, 2016. The regulations will come some years after that.

One option could be to proceed with a large scale IPR program with a pipeline to San Vicente as already envisioned. Subsequently, satellite advanced treatment plants could be built for DPR. That would allow San Diego’s waiver application to say we’re making substantial progress. It would also allow time for CDPH to issue regulations for DPR…it seems likely that won’t happen for many years beyond 2016.

Assuming the preferred path is IPR now and DPR in the future, the issue is still how to get things moving? What questions need to be addressed?

At the City Council meeting, PUD’s Marsi Steirer said the cost of IPR would not only be lower than the cost of desalination, it would be cheaper than imported water (around $1,000 per acre foot). That’s competitive with the price of imported water, but according to the Project report the actual cost is about $2,000 per acre foot—around where desalination is priced. Reading from the report:

“If full-scale reservoir augmentation is implemented, the city would not need to build a 7 million gallon wet weather storage facility to attentuate wastewater flow to Point Loma; reduced overall flow to Point Loma would reduce annual operations and maintenance costs at Point Loma plant and Pump Station 2 which conveys flows to Point Loma. Water salinity in the city water supply would be lower, potentially reducing costs further. Taking these factors into account PUD estimates the NET cost for IPR would be about $1,000 per acre foot.”

But wastewater has to be treated at Point Loma or at the North City reclamation plant, so are the savings really that great or is the cost just being shifted from Point Loma processing to North City processing? It will be interesting to see if the sewage treatment portion of our water bill shows a price decrease. So, next steps would appear to be:

  • IPR would benefit both water and wastewater systems, therefore proportional share of costs needs to be determined in order to prepare water and wastewater rate cases

  • Determine a contracting mode

  • Refine pipeline alignment, which represents an estimated 60% of total implementation cost

  • Coordinate with regional wastewater and reuse objectives including Point Loma waiver expiration in 2015

  • Monitor development of DPR regulations

In any event, it doesn’t seem wise to argue that we should embark on IPR because it is cheaper. It may or may not be less expensive than desalination or imported water in the long run, but IPR is clearly the right thing to do.

______________________________

I welcome any comments that can correct and improve on this report.

Some sources for this story that may be of interest:

 

Posted in Water, Water Purification Demonstration Project | Tagged: , | 8 Comments »

Advances in water recycling approved by San Diego City Council NR&C Committee

Posted by George J Janczyn on May 24, 2012

The San Diego City Council Natural Resources and Culture Committee (NR&C) approved on Wednesday (May 23) two substantial reports that recommend how recycled water can be used more effectively in the future as San Diego struggles with ways to reduce its extreme dependence on imported water that is becoming an increasingly expensive and less reliable source [link to the agenda].

According to the Recycled Water Master Plan, its purpose “is to evaluate opportunities to maximize non-potable reuse [of recycled water treated to tertiary standards] if IPR (Indirect Potable Reuse) projects are not pursued” [emphasis in italics is mine].

IPR refers to a series of advanced treatment processes applied to the tertiary water that results in purified water that is in essence distilled water and then to store that water in an underground aquifer or to blend it with imported raw water in an above-surface reservoir.

Nonpotable recycled water, of course, is limited to use in specific agricultural, irrigation, and certain industrial settings. A separate pipeline infrastructure must be built to deliver that water (“purple pipe water”), and you definitely can’t drink it.

This blog post, therefore, focuses on the subject of the companion to the Recycled Water Master Plan, the City of San Diego’s Recycled Water Study.

After considering a number of options, the Recycled Water Study mainly examined two possible ways IPR projects can be pursued in San Diego: 1) use IPR water to recharge groundwater resources, or 2) mix it with imported water that is piped into and stored in local reservoirs (sometimes referred to as “reservoir augmentation”). IPR, as you probably know, results in water that is of higher quality than the water we import from the Colorado River and Northern California and it can be used for any purpose, including for drinking, and delivered using our existing potable water infrastructure.

Another option examined in the Recycled Water Study, Direct Potable Reuse (DPR)–which would deliver the purified recycled water directly into the water distribution system instead of mixing it with imported reservoir water—has not been well-studied and would be difficult to implement without the development of new statewide regulations, so the study concludes it is not on the table for the near future in San Diego.

The Recycled Water Study envisions that continuous increases in the price of imported water along with decreased reliability and availability of imported supplies will soon make the relatively expensive IPR process competitive with imported prices (it’s already competitive with, if not cheaper than, the cost of desalinated water)…and will eventually be dramatically less expensive than imported supplies.

The Recycled Water Study was the outgrowth of an agreement between San Diego Coastkeeper, the San Diego Chapter of the Surfrider Foundation, and the City of San Diego, whereby the environmental groups agreed not to oppose the EPA’s Regional Water Board’s, and Coastal Commisssion’s approval of San Diego’s Clean Water Act waiver that allows the Point Loma Wastewater Treatment Plant to continue discharging into the ocean the sewage receiving only Advanced Primary instead of Secondary treatment. The waiver expires in 2015, with an application due a year before expiration, so time is of the essence.

If San Diego chooses not to pursue upgrades to the Point Loma treatment plant to full Secondary treatment standards before the expiration of the current waiver, there is widespread speculation that the governmental agencies are not likely to renew the waiver and the city could face huge financial penalties AND be faced with a full upgrade to the treatment plant.

Upgrading Point Loma to Secondary treatment at its current load would be exceedingly expensive partly because of the large wastewater flow it receives and partly because there’s little room to expand on the limited hillside space it occupies facing the ocean along Point Loma’s western slope.

So…the Recycled Water Study envisions that if enough water is recycled, particularly via the advanced IPR treatment process, a good deal less wastewater would be sent to Point Loma. Point Loma then would be burdened with treating less wastewater and it would be much less expensive to upgrade to Secondary treatment standards. In that scenario, the city could even apply for federal financial assistance to upgrade Point Loma to Secondary treatment. If nothing is done and the waiver expires, the city would face large fines, be forced to upgrade to Secondary treatment at greater ratepayer expense and would not be eligible for federal financial assistance.

The Recycled Water Study concludes that groundwater recharge opportunities are extremely limited given San Diego’s geography. As such, using IPR water for reservoir augmentation is the most realistic option for San Diego to incorporate purified recycled water into its its potable water portfolio.

(the above photos show a portion of the advanced treatment facility being used for the Water Purification Demonstration Project. Click to enlarge)

Therefore, a Water Purification Demonstration Project examining the feasibility of using the IPR process focusing on reservoir augmentation by the City of San Diego is currently underway. A prototype advanced treatment facility at the North City Water Reclamation Plant is producing a limited amount of IPR water while a parallel scientific study is being conducted on the feasibility of blending IPR water with imported water in the San Vicente Reservoir.

When the Demonstration Project is completed, a number of unfinished regulations and guidelines addressing IPR must be approved by federal, state, and local agencies before San Diego can implement IPR reservoir augmentation on a large scale.

One problem with the NR&C vote on Wednesday, though, is that the committee simply “approved” both reports to advance to the City Council. The motion to approve both plans made no recommendation as to which plan to implement; that is, whether to commit to nonpotable recycling in the future, or recommend a combination of nonpotable recycling and IPR projects.

This decision tree from the Recycled Water Master Plan illustrates the issue:

There was, however, some indication of the direction towards which the committee leans on this question.

During discussion before the vote, Councilmember Sherri Lightner appeared to favor developing a balanced plan, incorporating nonpotable and potable recycled water, especially since a significant amount of nonpotable water infrastructure already exists and there are contracts and plans already in place to expand that form of recycled water use.

Another issue is that the Recycled Water Study raises the possibility of a much larger capacity facility to produce the advanced treatment product water (or several new satellite IPR facilities) to achieve a goal of producing as much as 100 million gallons per day (GPD) of IPR water, and it implies that because the San Vicente Dam Raise Project will more than double the capacity of the reservoir, there would be capacity to handle it.

That raised a question in my mind, which I decided to ask during the public comment portion of the NR&C meeting: the fact being that the County Water Authority (CWA) is building the San Vicente Dam raise and it will own the rights to the additional capacity. Would CWA buy IPR water from the city or fill it with imported water? And if all the water in the reservoir will be mixed, would it then be delivered to all the CWA member water agencies…and would they be agreeable? I also suggested that due to the close proximity of El Capitan Reservoir (currently San Diego’s largest), why not consider using both San Vicente and El Capitan as receiving reservoirs for IPR water?

Later, during committee discussion, Councilmember and committee chair David Alvarez asked PUD staff about that. Assistant PUD Director Marsi Steirer allowed that San Diego would only be adding IPR water to the portion of the reservoir capacity that the city owns…and that if the city eventually did produce up to 100 mgd of IPR water, its portion of San Vicente reservoir could consist entirely of IPR water. My question regarding El Capitan was not addressed at that time, but I’ve since learned it was a point of discussion during production of the report.

Ms. Steirer later sent me email addressing that question. With her permission, I’m reprinting a portion of her reply here:

There are two principle reasons El Capitan Reservoir is not as good a choice for reservoir augmentation as San Vicente Reservoir: storage volume and distance.

Storage volume
The greatest value – the best use – of El Capitan Reservoir is to capture local runoff. The El Capitan Catchment [the land area that drains to the reservoir] generates the greatest amount of runoff of any reservoir in the San Diego region. In our region rainfall and runoff are highly variable. Much of El Capitan’s runoff occurs in the occasional high rainfall year; something like two years per decade have abundant runoff and the reservoir fills up. We then store this runoff water for use over several years. For this reason, our operational scheme for El Capitan is to keep storage space available in the reservoir in anticipation of high runoff years. The average runoff to El Capitan is 28,000 AFY.

San Vicente Reservoir, on the other hand, is primarily filled with imported water. The San Vicente Catchment does not generate much runoff. The average runoff to San Vicente is 4,000 AFY.

Basically, we keep San Vicente full with imported water and El Capitan relatively empty to capture local runoff.

[Note that in recent years – starting in 2008 and extending to 2018 – El Capitan has been more full than typical. San Vicente has been drawn down to facilitate construction of the new dam. We have compensated by storing more imported water at El Capitan. When San Vicente is completed and refilled, we will return to the typical operation at El Capitan.]

So, while El Capitan has a large total capacity [113,000 AF] the amount of water typically stored there is relatively small. The average long-term storage in El Capitan is about 40,000 AF. Compare this to the average storage in the future expanded San Vicente of about 180,000 AF.

San Vicente is a better choice for reservoir augmentation simply because it is larger. El Capitan, because it stores a smaller volume, does not offer the same level of retention, blending, and response time.

Distance
Constructing a pipeline to carry IPR water to El Capitan would be a difficult and costly endeavor. Conveying IPR water from North City to El Capitan would require eight to twelve miles of additional pipeline, and it would necessarily route through difficult terrain and environmentally sensitive areas.

But El Capitan isn’t entirely out of the question: Ms. Steirer also pointed out that the San Diego Reservoir Intertie Study although currently on hold due to U.S. funding constraints, includes plans to consider a connection between San Vicente and El Capitan. The conclusion, she says, is “if an intertie were established either directly or indirectly between San Vicente and El Capitan, we assume that it could accommodate a larger capacity IPR/RA project.”

Councilmember Alavarez also commented that he believes that IPR is 100% the only solution he believes will work to solve the issue of increasing local water supply and reliability, as well as dealing with the Point Loma plant upgrade.

It’s not certain when this item will be docketed for the full City Council, but a condition of the Coastal Commisssion’s approval of the last waiver was that the Study be presented in approximately two years, and that deadline is fast approaching. The City is also pressured to act quickly, because even if the Demonstration Project concludes successfully and the city promptly moves to develop a large-scale IPR operation, it certainly won’t be finished, and most likely construction wouldn’t even be started, by 2015. Therefore, the only way for the City to be assured it will qualify for one or more additional waivers would be to get an approval and timeline in place to implement a significant amount of IPR, and thus justify the delay in upgrading the Point Loma treatment plant.

 

Related local news reports:

 

Posted in Environment, Water, Water Purification Demonstration Project | Tagged: , , , | 3 Comments »

San Diego’s indirect potable reuse proposal without the hype

Posted by George J Janczyn on February 27, 2012

The City of San Diego is studying the feasibility of using purified recycled water to bolster its reservoir supply through its Water Purification Demonstration Project (originally called the Indirect Potable Reuse Reservoir Augmentation Demonstration Project).

Potable reuse has been a controversial and emotional topic in San Diego’s quest for new water resources. Provocative stands by certain politicians and pejorative headlines in some news media obscure a key underlying fact: for San Diego the real issue is unplanned vs. planned indirect potable reuse.

San Diego imports about 80% of its water from Northern California and the Colorado River. Imported water from these sources contains treated wastewater from over 345 municipal wastewater facilities [citation] — and when we get it, it only gets standard water treatment before delivery to customers. This is called unplanned indirect potable reuse. We’ve been doing it all along.

By contrast, under San Diego’s planned indirect potable reuse proposal, recycled water (aka treated wastewater) would subsequently go through a multi-staged advanced purification process rendering it similar in quality to distilled water. The purified water would be blended with our imported raw water in the San Vicente Reservoir. So, in fact we would actually improve the overall quality of the imported water before it goes to the final water treatment plant.

The goal, if the demonstration project is successful, is to produce 16 million gallons per day via the potable reuse process. That’s 16 million gallons per day less in imported water purchases, and 16 million gallons per day less in wastewater discharge into the ocean.

The Demonstration Project is also performing a limnology study to determine the reservoir mixing and dilution dynamics associated with adding the purified recycled water.

Over the last year the City of San Diego has been conducting educational presentations and guided tours of the advanced purification facility. The Water Reliability Coalition, a broad-based coalition of community organizations and groups has formed to further educate the public about potable reuse in San Diego. Polls indicate growing public acceptance of the process.

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Reprinted from a page in the Topical Guide section of this blog. That page includes the latest news reports on the subject and a selected bibliography on potable reuse and related topics.

 

Posted in Environment, Indirect potable reuse, Water, Water Purification Demonstration Project | 8 Comments »

Questions arise about the San Vicente Reservoir limnology study

Posted by George J Janczyn on September 27, 2011

Limnology [lim-nol-uh-jee] Noun. The scientific study of bodies of fresh water, as lakes and ponds, with reference to their physical, geographical, biological, and other features.

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San Diego’s Water Purification Demonstration Project is well underway now (aka Water Reuse Program). The project aims to assess the viability of advanced treatment and purification of reclaimed water as a supplemental source of drinking water.

The plan under investigation envisions that the purified reclaimed water will be blended with raw imported water in the San Vicente Reservoir and retained for a specified period of time to create an “environmental buffer” effect. Then the reservoir water would be piped to a water treatment plant to distribute as drinking water.

The project has under contract a limnology study to determine if the San Vicente Reservoir can provide sufficient detention time for the treated reclaimed water before it enters the potable distribution system. The study relies on modeling techniques — sophisticated ones to be sure — to predict the dynamics of water transit through the reservoir.

The question is: can the limnology study accomplish its task through modeling techniques alone?

That’s one question that San Diego physicist and fluid dynamicist Dr. Burton Freeman has been studying. Freeman examined the limnology study methodology and believes he found serious shortcomings. He documented them and asked for comments from Jeffrey Pasek, Public Utilities Dept. (PUD) Watershed Manager, Marsi Steirer, Assistant Director at PUD, Dr. Michael Anderson of the Water Purification Demonstration Project’s Independent Advisory Committee; Dr. Imad Hannoun, the Project’s limnology modeling consultant; and others.

Dr. Freeman agreed to let me publish his review here (may not display properly on mobile devices):

 

If Scribd doesn’t display the document, here’s a link to the PDF version.

I think Dr. Freeman raised some very pertinent questions, but the official response to Dr. Freeman’s review from PUD’s Jeffrey Pasek was:

“A full Project Report for the Water Purification Demonstration Project will be presented to the City Council in late 2012. The Limnology and Reservoir Detention Study of San Vicente Reservoir [including the modeling work] will be part of this report. At that time there will be opportunity for public review and comment on the report. Until then, sub-portions or internal drafts of the Project Report will not available for public review. When the draft of the full report is released, we would be please to meet with you and get your input.”

That’s pretty clear: no public input or review of the study process until they issue their full draft report late next year, although Jim Peugh, chair of the Independent Rates Oversight Committee, indicated a willingness to allow Dr. Freeman to give a presentation to the committee or a subcommittee, which may happen.

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Dr. Freeman’s points are important to be considered for the project as envisioned, but my own question about the project has been on a slightly different track: is there really a need for detention time at all?

Many scientific studies have already demonstrated that the advanced treatment process produces extremely high quality purified water…significantly better than the imported raw water that we use. So pure that it needs to be diluted somewhat for good mineral balance. Blending it in the reservoir with imported raw untreated water seems like the perfect solution.

A bay in the San Vicente Reservoir. Water cascades down the fill chute from the San Diego Aqueduct tunnel portal. Water level has been drawn down while the dam raise project is underway. The new water level will be noticeably higher than the bathtub ring indicates.

 

But what reason, other than fears about public perceptions about potable reuse, to require a lengthy detention time in the reservoir before it can be used? And what if the limnology study reveals that the treated water mixture will reach the reservoir’s intakes leading to the treatment plant sooner? Does that kill the whole project? I don’t think that’s acceptable.

Surely a reliable multi-barrier failsafe mechanism can be designed to make sure that any malfunction/contamination that may occur in the water purification process will immediately block tainted water from reaching San Vicente Reservoir.

In any case, San Vicente Reservoir has been drawn down considerably because of the construction to raise the dam and increase the reservoir size. After construction, it will take several years to refill to the enlarged capacity. That means there is no way to use real-time data about water currents and other factors that will affect the water added to the reservoir, and the relatively scant historical data about the reservoir may not be relevant because it’s based on the smaller reservoir’s size.

Dr. Freeman’s questions should be taken seriously…(and mine, too!).

 

Posted in Water, Water Purification Demonstration Project | Tagged: | 6 Comments »

San Diego Water Purification Demonstration Project honored with national award

Posted by George J Janczyn on September 16, 2011

 

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Advanced water purification facility begins operations for San Diego’s indirect potable reuse study (IPR)

Posted by George J Janczyn on July 1, 2011

The City of San Diego’s IPR study, now officially referred to as the Water Purification Demonstration Project by the Public Utilities Department, just passed a major milestone: the Advanced Water Purification Facility needed for the project is completed and operations have begun.

It’s been nearly one year (July 27, 2010) since the City Council approved a contract with Camp Dresser McKee for the advanced water treatment facility. The facility is a key component of the Demonstration Project which will study whether it’s feasible to purify recycled water to potable standards. The $11.8 million cost of the project is being funded with money generated from a temporary water rate increase for the past few years. The rate increase was cancelled after the needed funds were obtained.

The advanced purification facility was built to blend in as part of the North City Water Reclamation Plant. The reclamation plant currently cleans and processes wastewater to the tertiary level* which is clean enough to be used for irrigation and some industrial purposes (*this Wikipedia article provides a good overview of different levels of treatment).

Under the Demonstration Project, which is planned to take one year, a portion of tertiary-treated recycled water from the reclamation plant is diverted to the advanced purification facility where it is further processed through ultra- and micro-membrane filtration, reverse osmosis, and ultraviolet light with hydrogen peroxide for advanced oxidation and disinfection.

The advanced purified water will be continuously analyzed in laboratories. The remainder will be blended with the tertiary recycled water and delivered to recycled water customers. That’s almost like adding drinking water to the recycled stream, which means it’s likely customers will get better quality recycled water than before (for the duration of the demonstration project in any case).

Yesterday (Thursday) there was a celebratory “kick off” for the project at the North City Plant. Mayor Jerry Sanders, Councilmember David Alvarez, Public Utilities Department Director Roger Bailey, and Public Utilities Department Deputy Director Marsi Steirer spoke to mark the occasion. Afterwards we had a brief tour of the facility.

Local news media reporters were out in force covering the event. You’ll find varying points of view about the concept — and as usual there are a few folksy or provocative pieces along with potty headlines.

Here’s a collection of reports on Thursday’s event so far:

 

By the way, public tours of the Advanced Water Purification Facility are available. Register at http://purewatersd.org/tours.shtml.

Here are some photos (click for enlargements):

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Posted in Indirect potable reuse, Water, Water Purification Demonstration Project | 3 Comments »

How wastewater goes from polluted to pure

Posted by George J Janczyn on May 1, 2011

The American Chemical Society produced this video showing the steps that are followed in order to convert wastewater into purified drinking water (potable reuse). With the start of operations for San Diego’s Water Purification Demonstration Project fast approaching and educational outreach programs for community planning groups already underway, the video could be useful if used to supplement the city’s public outreach effort — which at times seems rough around the edges. Although it doesn’t cover reservoir augmentation with purified recycled water as San Diego’s project aims to do, the video delivers a fair amount of pertinent information and details with a matter-of-fact style.

 

 

 

Posted in Potable reuse, Videos, Water, Water Purification Demonstration Project | Tagged: | Leave a Comment »

Water news from the Natural Resources & Culture Committee

Posted by George J Janczyn on February 1, 2011

The San Diego Public Utilities Department submitted the following reports for the Feb 2 meeting of the City Council Natural Resources & Culture Committee.

 

Posted in Indirect potable reuse, Water, Water conservation, Water Purification Demonstration Project | Tagged: | Leave a Comment »

Should San Diego ozonate its wastewater for IPR?

Posted by George J Janczyn on October 5, 2010

San Vicente Reservoir, August 2010. Water level has been lowered to allow dam raise construction.

As San Diego prepares to embark on its one-year Water Purification Demonstration Project with the eventual goal of augmenting San Vicente Reservoir with purified wastewater (planned indirect potable reuse, or IPR), the biggest public concern about actually implementing that process — besides the considerable expense — will probably be water quality. The sheer persistence of the terms ‘recycled sewage’ and ‘toilet-to-tap’ in the news media is an indicator of that lingering concern.

To be sure, there’s reasonable certainty that the advanced treatment process is very reliable. Scientific studies have shown that the advanced steps of micro/ultra filtration, reverse osmosis, and UV/peroxide are effective for removal of pharmaceuticals and endocrine disrupting compounds (EDCs) from wastewater. Indeed, the City of San Diego previously completed a small-scale 18-month pilot testing program to determine the effectiveness of the advanced water treatment process being used in the new demonstration program, with the conclusion that the product water met all federal and state drinking water standards. However, the test is being repeated in this one-year project because the California Department of Public Health wants a test that would use the same size equipment and monitoring devices that we would use for a full scale project, according to Alma Rife, Public Information Officer for the San Diego Public Utilities Department.

Still, although pharmaceuticals and EDCs are held below state and federal threshholds (and are sometimes undetectable) after treatment, it is known that trace amounts can remain and there’s no consensus about their cumulative effect on humans. Further, the effect of EDCs on aquatic ecosystems (e.g., feminized male fish) has certainly been documented.

There’s growing awareness in many communities, being downstream from other communities, that treated wastewater already exists in their source water supply. That’s called unplanned indirect potable reuse and it’s certainly happening in San Diego via its imported water from the Colorado River and Northern California. Consider the following:

“…pharmaceuticals and EDCs have been detected in many water bodies around the world […] and are now considered ubiquitous wastewater contaminants. Undoubtedly, the major contributor of such widespread contamination is municipal wastewater discharge. Indirect potable water reuse, either planned or unplanned, occurs when wastewater treatment plant discharge comprises a portion of the receiving stream’s total flow. In many cases, surface water with some degree of wastewater influence is used as source waters for drinking water treatment facilities leading to the presence of these compounds in source and finished drinking water. Thus, the propensity for surface water or drinking water contamination will grow with human population growth and generation of additional wastewater.”

[S.A. Snyder and M.J. Benotti. Endocrine disruptors and pharmaceuticals: implications for water sustainability. Water Sci Technol. 2010;61(1):145-54]

The bottom line is that regardless of the source of our drinking water, whether Northern California or the Colorado River, we’re presently doing unplanned IPR. So now that we’re now looking at doing planned IPR through reservoir augmentation, is enough being done to address the trace contaminants that have been quietly tolerated in the past?

The treatment regime now contemplated for San Diego’s IPR project is: activated sludge, secondary clarification, tertiary precipitation, micro filtration, reverse osmosis, and UV/peroxide. The treatment plan is modeled on Orange County’s program because that program has already been permitted by the California Department of Public Health, according to Ms. Rife.

What about ozonation?

Ozonation is more effective than chlorine as a disinfectant and it can eliminate contaminants that even UV treatment can’t remove.

One doesn’t hear much about ozonation being used to treat wastewater. It’s more commonly used for drinking water treatment plants. In fact, a new ozonation facility near completion at San Diego’s Alvarado Water Treatment Plant is expected to go online by December (that plant treats water from San Vicente).

But when I visited the Southern Nevada Water Authority and Las Vegas Valley Water District water facilities to get a closer look at their operations, I learned that they just completed a pilot ozonation project at the Clark County Water Reclamation District, where much of their wastewater is treated (you may be aware that Lake Mead is their drinking water source as well as the destination for their treated wastewater).

Since Las Vegas already uses ozonation for their drinking water treatment plants, why also for wastewater?

Doug Drury, Asst General Manager for Water Quality, Research & Technical Services at Clark County Water Reclamation Plant (CCWRP), told me that some of the thinking that went into the decision to add ozonation to the other advanced treatment procedures included:

  • Substantial scientific documentation confirms the effectiveness of ozonation towards elimination of EDCs and PPCPs (pharmaceuticals and personal care products)
  • In testing, 60 samples for enteric virus were negative after ozonation, but not after UV treatment alone
  • Cryptosporidium was found in the Las Vegas Valley in recent summers
  • Lake Mead is less than half-full now but treated wastewater inflows remain the same, so there is less dilution and an apparent increase in concentration of contaminants in the reservoir
  • Potential environmental impact on aquatic ecosystems
  • Downstream water user concerns

HPLC unit at the Southern Nevada Water Authority Water Quality Laboratory

Not only did CCWRP perform that pilot study, but they approved $50 million for a permanent ozonation system. That’s a good sum of money; obviously they’re convinced that ozonation is doing something good. Interestingly, it appears they will also phase out reverse osmosis because of the 10-15% water loss involved in disposing of the resulting brine.

Ozonation is cited in another study as being the “most responsible for the removal of pharmaceuticals and EDCs” and “though many ozone plants also utilize chlorine, ozone is a stronger oxidant.”

In San Diego we’re looking to augment a reservoir that’s a lot smaller than Lake Mead. The San Vicente Reservoir will eventually have a capacity of around 250,000 acre-feet after the dam raise is complete. There’s only so much dilution that can occur when you add 16 million gallons per day of treated wastewater to a reservoir that size. So while public perception may find it acceptable to dilute wastewater in a large body of water such as Mead within the flow of the Colorado River, it could well be that the public will balk at the same thing being done at San Vicente Reservoir — and remember, public perception killed San Diego’s IPR project last time it was attempted.

Adding ozone to the IPR treatment regime could ease the public mind, but it’s probably a far-fetched idea for us. Ozonation on the wastewater side might convince some people who are still undecided about indirect potable reuse but it would be an extreme expense for what would really be a marginal benefit — and we’re already being squeezed with rising prices for water. Besides, we haven’t even managed to treat the bulk of our wastewater stream to secondary standards yet.

Ultimately, education will be key to a successful IPR project. The city’s public outreach and education program for the Demonstration Project has gotten underway with meetings with neighborhood planning groups, but those are just introductory project overviews. The challenge will be to go beyond the generalities (such as provided in the monthly IPR updates to the NR&C city council committee) and share complete, up-to-date, highly detailed water quality and cost information about IPR regularly and persistently. Tours of the new advanced treatment facility have been promised; the same should be done with the water quality lab. A blog-like news section on the city’s project website could help to stream out the details.

Many San Diegans have been squeamish about IPR despite it being a proven and safe technology. Providing access to plenty of information will be vital for overcoming that problem. On that note, this report from the independent Equinox Center is deserving of wide circulation (reprinted with permission).

 

Posted in Environment, Indirect potable reuse, Water, Water Purification Demonstration Project | 5 Comments »

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