Friday, September 28, 2007

Beware the Deadly Microsystems

Could water recycling help prevent blue-green algal growth in our reservoirs?

Sydney’s Lake Burragorang (Warragamba Dam), currently has a considerable growth of blue-green alga on the surface, -see the article and image below.

It shouldn’t come as a surprise to most people that if you dam a river and cause the water to sit in a huge puddle, algal growth is always a possibility. Add to that the nutrients run-off into the reservoir from last month’s rain and the current warm weather, and algal growth becomes almost inevitable.

As the article below suggests, it’s probably not a major problem. Blue-green algae tend to float towards the surface, whereas we have the capability to draw water supplies from much deeper. Nonetheless, these types of algae do produce a number of chemicals which are released into the water. Some of these may simply cause the water to taste or smell bad, but some are highly toxic.

The article quotes NSW Water Minister Phil Koperberg stating that recent testing has “detected some Microsystems” in the water. This could possibly mean that there are lots of computers that have been dumped in the reservoir. However, it is more likely that Mr Koperberg was misquoted and was actually referring to microcystins, -a type of blue-green algal toxin.

The current NSW Government does not plan to construct a planned indirect potable water recycling scheme that involves recharging Warragamba Dam. They have clearly stated that they are opposed to such a scheme because they don’t believe that the public would support it and because it would be expensive.

Nonetheless, it would be interesting to consider the impact that such an IPR scheme may have on the propensity for algal growth. We could look at the relative loads of the key nutrients nitrogen and phosphorus in the reservoir and at how effectively we may be able to dilute these with lower concentrations of nitrogen and phosphorous from advanced-treated recycled water.

Furthermore, recharging the reservoir and extracting the majority of our water supplies from it, would keep the water moving through the system, -preventing nutrient build-up and stagnation. Compare this with the current plan to replace much of the eastern suburbs’ water use with desalinated seawater pumped directly into the distribution system. This would reduce demands on Warragamba supplies (as it is intended to do), causing the water there to travel more slowly through the system.

Just another angle to consider for water supply planning…

Damn that algae - it's a blooming nuisance

Alexandra Smith
Sydney Morning Herald
September 28, 2007

A BLUE-GREEN algal bloom has taken over most of Warragamba Dam, with small levels of toxins found just below the surface.

Recent testing of the algae had shown three positive samples of microcystins, toxins that can cause skin irritation and stomach upsets if consumed in large doses. But NSW Health has stressed that the quality of Sydney's drinking water is not under threat.

Kerry Chant, the acting NSW chief health officer, said the levels of toxins were very low and had been found about three metres below the surface, not from where drinking water was being sourced.

The Water Minister, Phil Koperberg, said the bloom now stretched across 75 per cent of the dam - more than 58 kilometres - and more than twice the area it occupied at the beginning of the month.

He said it was possible drinking water could be mildly affected, but this would be limited, with water being safely drawn from 48 metres below the algae.

"There could be a discernible odour or taste with the water in the coming months," he said.

Warmer weather had provided the perfect conditions for the bloom to grow and could be present until at least Christmas.

"It is a bloom which, due to the warm weather, is likely to persist," Mr Koperberg said.

"It is very unlikely, unless there is some unforeseen meteorological event, that this bloom will either dissipate or disappear during the summer. It's, more likely than not, going to be around at Christmas."

Mr Koperberg said he would be provided with updates on water quality and testing.

"Testing is being conducted regularly by the Sydney Catchment Authority and Sydney Water of both the raw and treated water before it is supplied to Sydneysiders to drink," Mr Koperberg said.

"It is not a health risk whatsoever, even though part of the rigorous testing that Sydney Water and Health undertake has detected some microsystems - which are a group of molecules which contain some toxicity.

"Those levels are well below the Australian standards for drinking water safety.

"The main issue with this bloom is its visibility."

Tuesday, September 25, 2007

IPR Plans for San Jose

I know this blog is supposed to be “Water Recycling in Australia”, not “Water Recycling in The USA”. However, I think it is important for Australians to be aware that current Australian plans for indirect potable reuse (IPR) are not unique, -far from it!

The following is an article from the Contra Costa Times in San Jose. San Jose is the third-largest city in California, and the tenth-largest in the United States. It is a wealthy city, commonly referred to as the “capital of Silicon Valley”.

As the article makes clear, the major concerns are not whether the technology exists to safely recycle drinking water, but whether the community will be able to overcome the all-too-familiar psychological barriers to planned (as opposed to unplanned) drinking water recycling.

It will be interesting to watch the proposal develop (or otherwise!) during the coming months and years.

Making sewage water good to drink
Valley District, San Jose Look to Ensure Adequate Future Supply
By Paul Rogers
Mercury News
Contra Costa Times
25 September 2007

The Santa Clara Valley Water District and the city of San Jose are beginning talks on a bold new strategy to boost water supplies: making sewage water clean enough to drink.

If the public backs the plan, one day millions of gallons of the purified water could be pumped into streams and groundwater aquifers across Santa Clara County and mixed with existing drinking water supplies.

The county now provides half of its drinking water from wells that pump water from those aquifers. The other half comes from the Sacramento-San Joaquin River Delta.

"This is a homegrown resource. It is the most reliable supply you can have," said Eric Rosenblum, division manager for San Jose's South Bay Water Recycling Project.

"It is much less dependent on the weather than other sources. It is a great new tool to meet water needs."

The potentially controversial idea, still in the early stages, will be discussed this morning at the water district's weekly board meeting in San Jose. A final, detailed proposal isn't expected until next year.

Experts note that the technology exists to take sewage water and purify it to levels that meet California drinking water standards using an array of techniques such as reverse osmosis, microfiltration and ultraviolet light.

But in several areas around California - from San Diego to Pleasanton - attempts at blending purified wastewater with drinking water aquifers have been dropped after public outcry from critics who call the projects "toilet-to-tap."

But some water districts have already moved ahead with projects.

The Orange County Water District will christen a new $480 million project in November to produce up to 70 million gallons of recycled water a day from treated sewage. It will be used to recharge drinking water aquifers that serve Anaheim, Huntington Beach and other cities.

The project - the largest of its kind in the United States - came after nine years of public hearings and scientific studies. It won permits from the U.S. Environmental Protection Agency and the state Department of Public Health.

Cautious approach

Keith Whitman, water supply manager for the Santa Clara Valley Water District, promised that the district will take a similarly cautious approach.

"What we don't want to end up with is what's happened in other areas where you have fear and politics cause a backlash," he said.

Because California's population is expected to grow from the current 37 million to more than 52 million by 2030, the state Department of Water Resources recommended four years ago that California triple its use of recycled water, now about 500,000 acre-feet a year, by 2030.

Nearly all the recycled water in the state, however, goes for non-potable uses such as irrigating crops, cooling power plants, and watering golf courses, cemeteries and highway landscaping.

San Jose has used it in those ways for a decade.

In 1997, the city began delivering recycled wastewater across the county through purple pipes from its sewage treatment plant in Alviso. The project now has 540 customers and provides about 10,000 acre-feet of water a year - nearly 3 percent of total county demand. An acre-foot is about 326,000 gallons, or the amount of water a family of five uses in a year.

Customers for recycled water include San Jose Municipal Golf Course, Metcalf Energy Plant in South San Jose, Oak Hill Cemetery and dozens of schools and parks.

The city sells the water at a discounted rate. Originally, the $225 million project was built after state water regulators ordered the city to stop pumping so much treated fresh water into San Francisco Bay, where it was diluting brackish marshes and changing the bay's ecology.

But now, the city and the water district see the project as a potentially significant source of drinking water.

Today, the water district board will vote whether to allow its staff to negotiate with the city to expand the use of recycled water. If approved, as expected, the final agreement would come next year.

No project would be built without public hearings, an environmental impact statement, approval from the state Department of Public Health, the Regional Water Quality Control Board and the San Jose City Council.

In early feasibility studies, the water district has envisioned constructing a $52 million advanced treatment plant. It would be located in Alviso next to the city's wastewater treatment plant and produce the same amount of recycled water now produced by the plant, about 10 million gallons a day, but at a higher quality. It would remove salts that, if left untreated, would eventually build up in irrigation water, causing grass to brown and harming redwoods and other trees in clay soil.

Could open by 2012

Whitman said construction could begin on the plant by 2010 and open by 2012.

After that, if the city and district want to blend its recycled water with groundwater aquifers, they would build one or more "satellite plants" in places like Coyote Valley and further treat the water to drinking water standards.

The state Department of Public Health requires any recycled water used on food crops, school fields or residential irrigation to be treated to tertiary standards - the highest level of sewage treatment, and disinfected with chlorine. San Jose's now meets that standard.

But the health department does not have uniform guidelines for pumping it into drinking water aquifers. New rules the department is drafting would require it to meet drinking water standards.

Environmentalists are generally supportive.

"Recycled water is going to be a critical component of California's water future," said Linda Sheehan, executive director of the California Coastkeeper Alliance, in Fremont. "It has to be, because of population growth and because climate change is going to reduce the amount of snowpack in the Sierra."

Sheehan said, however, that the water must be rigorously tested not only for traditional contaminants such as bacteria but also for minute levels of pharmaceuticals, hormones and other contaminants that can get through sewage treatment plants unfiltered.

The largest hurdle if the project is to go forward is the "yuck factor." Even if the science is sound, how do you persuade people that it is OK to drink toilet water?

In Sonoma County, some vintners have been fighting a proposal this summer to use recycled water from Santa Rosa to irrigate wine grapes.

"I am worried that there is a huge backlash on recycled water on our grapes," Katie Murphy, vice-president of the Alexander Valley Association, told the Santa Rosa Press Democrat in May. "I fear negative publicity - and that could linger over our wine industry for a long time."

In Orange County, water officials held hundreds of public meetings with hospitals, civic groups, religious leaders and others. They noted that astronauts have drunk recycled water for years - and that anyone drawing water from a river is drinking the recycled wastewater of cities upstream, as Los Angeles does with Las Vegas, and Memphis with St. Louis.

"We are very concerned about public opinion," said San Jose's Rosenblum. "People in Silicon Valley value innovation and technology, but they also value a high quality environment and a reliable source of water. So to the extent that using recycled water for potable purposes helps achieve those goals, I think the people in our area will be open to its use."

Friday, September 14, 2007

The San Diego Saga

The City of San Diego (California) is a widely cited case-study regarding the unsuccessful implementation of an indirect potable water recycling (IPR) scheme. Ironically, it is also an important case-study for where some of the best science has been conducted to establish and demonstrate the safety of the practice.

San Diego is often credited with the popularisation of the intentionally yuck-inducing term ‘toilet-to-tap’. An article from CNN in 1997 stated "If all goes according to plan, by the year 2001, the city's sewage water will be treated and recycled right into the drinking tap". Hence intentionally emotive language, crafted to emphasise a link between sewage and taps can be traced back at least a decade. Perhaps not surprisingly a highly emotional debate ensued.

The plan in San Diego was to pipe highly treated municipal effluent to the San Vicente Reservoir, where it would mix with raw river water and become part of the city’s raw water supply. This proposal met with considerable community opposition; apparently largely on the basis that IPR seems distasteful. However, an editorial from the Sacramento Bee puts some of the issues in perspective:

"Alas, it seems time to let San Diegans and any other squirming citizens in on a little secret about water supplies: Toilet-to-tap is as old as civilization in California. And if San Diego shuns blended toilet water, it's about to become very thirsty.

With little groundwater underneath it, San Diego has two primary supplies. One is the Sacramento-San Joaquin Delta. The other is the Colorado River. The proposed project, to reuse water rather than drain it into the ocean, is one viable way to create a reliable local supply for San Diego. But it does involve the blending of treated water with untreated water in a reservoir. Technically, this means drinking treated toilet water. Is this really new for San Diego or most cities? Of course not.

Consider the Sacramento and San Joaquin rivers, whose waters San Diego draws from the Delta. More than 300 farmers and cities are permitted to discharge their treated and untreated runoff into these rivers. Counties empty treated sewage water into rivers every day. Almost 10 percent of the average flow of these rivers is discharge, according to San Diego's water department.

Yuck? Consider the Colorado River. Las Vegas dumps 58 billion gallons of treated sewage water into nearby Lake Mead, from whence it flows into the Colorado. More than 17 percent of this river's flow is discharge. Guess who drinks some of this, San Diego?"

Although IPR is not current San Diego City policy, it seems the issue will not disappear until long-term water shortages are resolved. The city’s Union-Tribune newspaper today reported on an on-going disagreement between the San Diego Mayor Jerry Sanders and City Attorney Michael Aguirre.

Mayor Sanders has publicly rejected IPR for San Diego, while Attorney Aguirre has pointed out that “we rely on recycled water right now…We import recycled water from the Colorado River”. The Union-Tribune stated that Attorney Aguirre accused the mayor of relying on polls to dictate his water policies and not educating the public.

It’s certainly not for me to suggest how San Diego should best manage its water and I don’t pretend to have any capacity to be able to do so. However, it is insightful to observe the debate and consider just how significant politics and populism are in the determination of long-term infrastructure planning.

Friday, September 07, 2007

Las Vegas Wash

Greetings from Las Vegas.

I came through Las Vegas primarily to visit the new Water Quality Laboratory and Applied Research & Development Center of the Southern Nevada Water Authority (SNWA).

This facility is practically ground-zero in the USA for research into emerging water quality issues such as the presence of pharmaceuticals and endocrine disrupting compounds (EDCs) in drinking water.

I was invited to visit Dr Shane Snyder, -an environmental toxicologist and Research & Development Project Manager at SNWA. Throughout the last decade Shane has conducted research focussing on water quality at Lake Mead on the Colorado River, -the home of Hoover Dam and one of the most important drinking water sources in the USA. Lake Mead is a vital water supply for Nevada, Arizona and California.

As Shane explained to me, Lake Mead and Hoover Dam are also an example of a planned indirect potable water recycling (IPR) scheme. All treated municipal effluent is recycled one way or another in Las Vegas. Much of it is used directly for irrigation, but a significant proportion is also returned to Lake Mead via a waterway known as the Las Vegas Wash.

The Las Vegas Wash is a flow of water that is comprised of urban runoff, shallow ground water, reclaimed water, and stormwater. As described on the website of the Las Vegas Wash Coordination Committee, reclaimed water (ie. recycled municipal effluent) is normally the largest contribution of water to The Wash.

Three municipalities (Las Vegas, Clark County and Henderson) discharge treated effluents into The Wash to give a combined total of more than 500 million litres per day. The discharged water is generally conventionally treated sewage effluent with nutrient removal. There are no advanced water treatment processes such as reverse osmosis or advanced oxidation prior to discharge. As a result, there have been a number of pollution concerns in Lake Mead. One of the major concerns has been salinity. Furthermore, Shane’s work over the last decade has shown that endocrine disrupting compounds (such as estrogenic hormones) have had a detrimental effect on fish in the lake.

Prior to human consumption, the water from Lake Mead (and Lake Las Vegas) is treated by processes including flocculation, ozonation, dual media (anthracite and sand) filtration and chlorination.

As the fastest growing population in the USA and being in the middle of the Mojave Desert, sufficient clean drinking water is not something that Las Vegas can afford to gamble. The city invests in water in a way that suggests that it truly recognises the value of its most precious resource. It maintains a comprehensive water quality analysis program and on-going research aimed at process optimisation and continual improvement.

The image below shows a pilot-scale ozonation reactor at one of the Las Vegas water treatment plants.

Here is Lake Mead showing dramatic evidence of the drought experienced during the last decade. This deck was built for fishing from. An almost identical picture appeared on the front page of the New York Times earlier this year.

This is another view of Lake Mead. In the distance you may be able to see some boats crowded into a receding marina. Well above the boats you can see a white band on the rocks behind. This is precipitated calcium carbonate (‘hardness’) from the lake water and reveals the previous water height. This image from the New York Times shows it even more dramatically.

The next two images are from Hoover Dam. Again, note the white scale on the rocks showing evidence of previous water height.

Finally, water from the lake is treated at a full scale Las Vegas water treatment plant, ready for distribution to customers.

Wednesday, September 05, 2007

Wentworth Group promotes IPR

The Wentworth Group of Concerned Scientists is a group of respected Australian scientists with an aim to raise awareness and facilitate debate regarding some key environmental issues. Their members include Prof Tim Flannery, Prof Peter Cullen, and Prof Mike Young.

The Wentworth Group have released a number of significant documents including their Blueprint for a Living Continent in 2002 and their Blueprint for a National Water Plan in 2003. You can also find a brief article about the Wentworth Group's contribution to the water debate here.

Today’s Adelaide Advertiser reports the Wentworth Group advocating the expansion of Adelaide’s municipal water supplies by means including potable and non potable water reuse and urban stormwater harvesting (see below).

I haven’t yet found the actual source document where the proposed strategies are described. Please let me know if you come across it…

A State of Emergency
By Cara Jenkin
The Adelaide Advertiser
September 05, 2007

SOUTH Australians need to drink recycled sewage, recycle stormwater and consume 50 per cent less to safeguard water supplies for the future, the Wentworth Group of Scientists says.

They have called for reliable sources to be established as a matter of urgency to replace SA's reliance on the River Murray.

The group's four water experts, University of Adelaide Professor Mike Young, former Adelaide Thinker in Residence Peter Cullen, University of Sydney Emeritus Professor Bruce Thom and CSIRO environmental adviser Peter Cosier have outlined several strategies.

The use of recycled wastewater and stormwater, limits on groundwater use, a buyback of water licences and an overall reduction in consumption was necessary.

Professor Young said all the options to source water must be examined.

"We need to put sewage recycling strongly on the table as an option, for both drinking and for outdoor use, and evaluate (all the options) carefully and thoroughly," he said.

Professor Cullen said 50 per cent of the water allocated from rivers would be less reliable as climate change took hold.

"We need to put controls on groundwater bores right across the Adelaide Plains," he said.

"We are pumping vast amounts out of our reserves when we might not have anything come out of the taps this summer."

Professor Thom said there was a "tremendous loss" when stormwater was being discharged out to sea.

Mr Cosier said State and Federal Government reforms to allocate water more stringently and sustainably had also failed to make progress in the past three years.

"One of the big criticisms SA had in the past was asking others to do what they weren't prepared to do themselves," he said.

Monday, September 03, 2007

Swanbank Power Station on Recycled Water

This week is a significant milestone for recycled water use in Queensland with a key component of the Western Corridor Recycled Water Project reaching fruition.

High quality water from the new Bundamba Advanced Water Treatment Plant is now delivered direct to the Swanbank Power Station. This is currently 13 ML per day, which would otherwise be taken from Brisbane’s Wivenhoe Dam, and expected to increase to 20 ML per day when water restrictions are relaxed.

Further details below from a media release today from the Queensland Water Commission.

Workers toasted with a top drop: Beattie
QWC Media Release
03 Sep 2007

BUNDAMBA: Premier Peter Beattie and Deputy Premier Anna Bligh today lifted glasses of recycled water to toast the success of the first completed stage of the State Government's $9 billion Water Grid.

Mr Beattie and Ms Bligh drank the purified recycled water during an open day at the Bundamba Advanced Water Treatment Plant, the first stage of the $2.4 billion Western Corridor Recycled Water Project to have been completed.

This week the Bundamba Advanced Water Treatment plant started delivering supplies to the Swanbank Power Station via a 7.3km pipeline.

Stage 1A of the Western Corridor Recycled Water Project also involved building a 9.6km "triple" pipeline from the Goodna and Bundamba wastewater plants to the new Bundamba Advanced Water Treatment facility.

Mr Beattie said purified water would not be introduced into drinking supplies in the Wivenhoe Dam system until October 2008, when the Western Corridor Recycled Water Project was running at full steam, taking water from Bundamba and two other Advanced Water Treatment plants at Luggage Point and Gibson Island that are under construction in Brisbane.

"This is one of the most satisfying drinks of water I've ever had," Mr Beattie said.

"Ten months ago, this was a paddock. Now we have a high-tech plant producing some of the best-grade recycled water in the world, which easily meets Australian drinking water standards.

"Out of the worst drought in this region's history we have developed a long-term solution. This is Smart State at work.

"As well as securing our drinking supplies and driving power stations, it will eventually provide our farmers with a reliable water supply. Industry in this growth belt also will be able to access the recycled water."

Ms Bligh used her taste of purified water to toast the 800-strong workforce who laboured long and hard to ensure the success of the project.

"Despite the recent rains, they met a timetable that some said was impossible. It's a tremendous feat of engineering recognised around the world," Ms Bligh said.

At full capacity, Stage 1A will produce 20 million litres of purified recycled water a day for Swanbank, freeing up Wivenhoe drinking water for more than 140,000 people.

At present, flows are reduced to about 13Ml because people in south-east Queensland are using less water than normal under Level 5 restrictions.

"On the upside, this water is of such quality it can be reused by Swanbank more times than the water that was being taken directly from Wivenhoe. This means further water savings in the order of 10 per cent - at least another million litres of drinking water a day for south-east Queenslanders," Ms Bligh said.

When completed in October 2008, the Western Corridor Recycled Water Project will have the capacity to deliver 182ML a day to Swanbank and Tarong Power stations and into Wivenhoe Dam. Its ultimate capacity is 310Ml a day.

The Government also is investigating expanding the capacity of the Gold Coast Desalination Plant at Tugun, from 125Ml a day to just over 170Ml/day meaning more than half of SEQ's water needs will come from sources that aren't dependent on rainfall.