I was pleased to see this recent report out of a US-Canadian advisory panel that the best option to manage varying water levels of the Great Lakes is, actually, nothing. Homeowners adjacent to shorelines that have risen and fallen significantly in the past 20-30 years were hoping that dams or similar water flow controls between the Great Lakes would constrain the water levels with less variation. But remember, these are the Great Lakes. That’s a lot of water we’re talking about, and building big dams on that scale would be massive in cost (both dollars and environmental damage). Plus, there’s no guarantee that dams can prevent long-term trends in water balance between rainfall, runoff, and evaporation. I mean, look at Lakes Powell and Mead on the Colorado River: the physical infrastructure can’t overcome the lack of precipitation and runoff in the Colorado basin when withdrawals continue unabated, and consequently water levels have declined on the order of 100 ft since the lakes filled.
So let’s see, a project that would benefit some shoreline property owners but have huge infrastructure and environmental costs…doesn’t exactly sound like something I’d want my taxpayer money paying for. It’s a relief that the advisory panel was not swayed by a few annoyed shoreline residents into unsound advice. The “do nothing” alternative can sometimes be a high bar to meet and exceed.
Anyone out there ever had unexpected house guests? You’ve got your plan for the evening, maybe just enough food for yourself or your family, and surprise, there’s an old friend at the door. You try to play it cool and look like it’s no inconvenience, praying that you have enough in the fridge and maybe an extra bottle of wine or couple of beers to be hospitable. It’s a tight position.
In the Middle East, Jordan is a relatively responsible water manager. Limited in water supplies, the country’s population growth has stalled and development has been relatively well planned to balance ecological needs with human needs. But Jordan has a lot of unstable neighbors, and therefore tons of unexpected, unplanned-for guests in the form of refugees. Palestinians escaping Israel account for one third of the country’s 6.5 million people, plus they took on influxes of Iraqis in 1990 and 2003 (roughly 450,000 remain), and today, they are the refuge for many Syrians. In an effort to meet the unexpected extra demand, the country started tapping its main aquifer in the 1980s for the Palestinians, and briefly stopped the extraction for ecological purposes (save the wetlands!) but could not supply the refugees without it.
Now the Azraq aquifer declines approximately 1 m annually, as about 56 million cubic meters are annually withdrawn; the aquifer can only naturally support 20 million cubic meters of annual withdrawal. Taps in Amman run dry in the summer, and the declining levels are increasing the groundwater’s mixing with a deeper saline reservoir, so that the remaining groundwater is saltier and saltier. Jordan is trying its best to do the right thing — take care of the refugees, preserve the wetlands, supply everyone with water, and get the withdrawals back in balance with natural recharge. Jordan already recycles its wastewater for indirect potable reuse, it has plans for desalination, and it’s trying to get local people and neighbors on board with water plans. So type A. But it won’t last forever if these refugee surges keep coming…I’m guessing they wish their neighbors would all just get along.
I thought I should post this, after my enthusiasm for recycling in my last post: sometimes turning a waste stream into a marketable resource is a bad idea. In fact, sometimes it’s a disaster. Turns out, chemical companies thought about this a lot over the years, especially in the pre-regulation days. In the 1940s and 1950s, Dow Chemical and Shell produced plastics from allyl chloride, and one of the by-products was a chemical called 1,2,3-trichloropropane (TCP). Side research suggested that this compound could be added to a popular fumigant (Shell’s was called D-D, Dow’s was called Telone) without ill effects. A Shell memo from 1981 suggests that the company made $6.3 million in fumigant sales, and saved $3.2 million in disposal costs for TCP. In effect, the companies were able to use this waste as “filler” in a marketable good — perfect!
Originally the companies claimed that TCP was effective at killing nematodes, but subsequent research was unable to prove these claims. In the meantime, the fumigants were used extensively in California’s Central Valley, where the compounds most resistant to degradation entered the groundwater, and the EPA, Clean Water Act, Safe Drinking Water Act, and Superfund law all came into effect. Furthermore, we know today that TCP is a carcinogen, and more than 200 water wells across the Central Valley have elevated levels of TCP. Although Shell stopped selling D-D in the 1980s and Dow changed its Telone formula in the 1990s, TCP will persist in affected groundwater for years. This means that there are quite a few lawsuits out there to force these two companies to pay for additional treatment for existing water supplies and for external water supplies where treatment is unavailable. The companies already settled with one small municipality for $13 million, which suggests that there are a few more settlements headed their way…
So to be clear, recycling works when you’re not dealing with hazardous material that may become a human health risk in the future. It does not work when you try to hide toxic materials in useful products.
There are people out there studying global cycling and reserves of elements. Carbon cycling is well known, from climate research, but there are headlines now and again about trace elements that we might run out of — tantalum, neodymium, germanium, gallium — that play a role in industrial products or processes. But the really scary numbers are for phosphorus, if you believe the USGS estimate of current reserves: peak production by 2030 and exhaustion of the global reserves by 2100. Remember, phosphorus (along with nitrogen) is responsible for revolutionizing our agricultural yields in the mid-1900s, and farmers throughout the developed world use it heavily.
The reason why I think phosphorus scarcity is a good thing, is that there’s another obvious source of phosphorus in the world: human and animal wastes. When the price of newly mined phosphorus gets high enough, projects to recover phosphorus from wastewater treatment plants or feedlot manure piles will be economical. This type of “recycling” phosphorus is, in my humble opinion, more sustainable in the long term than the typical “use it and throw it away” thinking we have about, well, everything we use.
It’s refreshing to see that my line of thinking is shared by those in the Encina Wastewater Treatment Plant in Carlsbad, California. They performed a pilot study last year and have begun evaluating the cost-effectiveness of implementing a full-scale system to recover phosphorus in little pellets to be used as fertilizer. The pellets are composed of phosphorus, nitrogen, and magnesium in a mineral called “struvite”. Researchers at Eawag have found that struvite precipitates more readily from urine than mixed wastes, and they have therefore pushed for “source separation”. (Side note: It wasn’t the best thing to be the subject of their urine collection system while I worked there.)
Think about some of these trends, though. Wastewater treatment has historically been about meeting some minimum level of treatment so that wastes could be dumped into our waterways. Between the biogas recovery and fertilizer production, there is a shift towards viewing wastewater as a potential resource instead of a waste stream. Any way to recycle these “wastes” back into productive use will lead to not only greater sustainability for wastewater treatment, but also larger profits for the treatment plants. I will post more about this when it comes to the Los Angeles water balance, but it is worth noting that most of what exits a wastewater treatment plant is water. If we could recycle this, too, wastewater treatment could be a huge boon to the energy, agricultural, and water needs of our society. Now that’s impressive.
Last one of these, I promise: Sacramento is also expanding its wastewater biogas facilities. Construction is underway on a co-digestion plant for fats, oils, and grease, and they’ve even agreed to accept material shipped from outside Sacramento, which was previously off-limits. Seems only fair if they mention EBMUD, but again, the media makes them sound like trendsetters…
Today’s news includes a tidbit from Humboldt, California. The Humboldt Waste Management Authority is embarking on a food-waste-to-methane project, with a pilot project starting this week and full scale requests for proposals to begin in May. Besides removing food wastes from landfills, the project will cut fuel costs associated with shipping to the landfills in Redding and Medford, and it even has potential to generate enough energy to be sold back to the grid. Sound eerily familiar? That’s because EBMUD just announced its net energy generation from an identical project last week. It is a good sign that other waste management utilities in the state are following EBMUD’s lead. Plus, if the economics of the energy generation work out, these waste utilities might have to start answering to their customers as to why they have not implemented this kind of energy- and cost-saving project.
The local water utility here in the East Bay has achieved a remarkable feat: they are producing enough energy from their main wastewater treatment plant to sell power to the grid. I had hoped to report on this after viewing the plant myself, but I was turned away from the Grand Opening Dedication Ceremony of their new gas turbine on Tuesday. Turns out that I needed media credentials. Oh well.
Wastewater treatment is notoriously energy intense, if for no other reason than that water is heavy to move around. According to the East Bay Municipal Utility District (EBMUD), the average California power cost to deliver one million gallons of water is approximately 7000 kW-hrs. So a common move towards energy efficiency is to cap all tanks for water and sludge, then recover the methane (a.k.a. natural gas) to be burned for energy. This also alleviates a lot of odor issues with wastewater treatment plants — trust me, I used to work at one in East St. Louis. Well, EBMUD had already done that. They had 3 gas turbines running about 6.3 MW, which was nearly enough (90%) to power the wastewater treatment plant, and they had excess methane. So they just bought and installed a big, efficient gas turbine, 4.5 MW, to use the excess methane and generate energy in excess of their needs. That’s right, a wastewater treatment plant is producing enough power to sell some to the grid.
Now, the East Bay utility in general will still need to purchase energy from the grid occasionally for water treatment and delivery and maybe office building use. Their 2010 energy purchase amounts to 9.3 MW, more than the roughly 3.8 MW excess capacity that they just added. So they’re not exactly going to get rich. Yet.
The real secret behind the EBMUD strategy is the food wastes that they accept (for a fee) from regional restaurants, wineries, cheese producers, and chicken farms. They feed all this disgusting junk to a tank full of microbes, and end up with way more methane than standard sewage would provide. This stuff is too complex to toss in a standard wastewater treatment plant or even to travel through sewer pipes, but a bunch of trucks deliver it every day to the specialized bioreactors EBMUD has had since 1991. Considering that this junk would otherwise end up in a landfill, emitting methane (a greenhouse gas far more potent than carbon dioxide) unchecked, this economical decision also makes sense from an environmental perspective. It’s nice when we can all agree on something.