AdEdge Water Technologies' Rich Cavagnaro and Sahar Fathordoobadi discuss the importance of chemistry and how it serves as the basis of everything...
>In 1993, the city of San Jose gambled millions of dollars that it could turn the water you flush down the toilet or use to wash the dishes into something people would buy.
Now, years after the city launched its network of pipelines to distribute treated wastewater to golf courses, parks and other customers, officials are still waiting for the large payout they anticipated, according to an article in the San Jose Mercury News. Costs have soared to more than double the projections, while the system has attracted customers for less than half the amount of water officials estimated.
This week, the city may up the ante by tens of millions of dollars. On Tuesday, the city council is scheduled to vote on a proposed multimillion-dollar expansion to North Coyote Valley as part of a larger agreement to serve Calpine's proposed 600-megawatt power plant there. The Santa Clara Valley Water District has signaled its willingness to pay some or all of the city's $40 million share of the $50 million extension, with Calpine paying the rest over 30 years.
The city or water district could spare itself the expense of extending the system for Calpine. A private company, Great Oaks Water, has offered to build a 20-inch pipeline to supply the 4 million gallons of recycled water Calpine needs to cool its power plant each day.
But city officials have ignored the company's proposal, arguing that it is too limited in scope. They are pressing for a pipeline more than double that size, which in addition to the power plant would potentially serve dozens of customers and allow for an ambitious expansion into mid- and south-Coyote Valley and beyond.
San Jose is under a state order to limit the amount of treated wastewater it puts in the bay each day to 120 million gallons. If it exceeds that curb, the city could be forced to halt new development projects because of the added wastewater they would generate.
Protecting the bay
So the question for San Jose is not whether, but how, to divert treated wastewater from the bay. Should public agencies spend millions more to expand a system that auditors -- and the city's own staff members -- said is the least cost-effective way of dealing with the problem?
In a report last year, the auditor's office found that the project was distributing less than a third of the 21.1 million gallons a day officials had projected.
Costs had more than doubled: Officials had planned to spend $64 million, but ended up allocating $141 million. Staff time, feasibility studies, and operation and maintenance costs brought the total to $256 million.
A draft report given by the officials cam eto the conclusion that the project would not be cost effective, mostly to the expensive piping system.
Officials conceded that early estimates were overly optimistic, but he said that the program is making great strides, adding dozens of customers and diverting more and more wastewater each year. The city lost some potential agricultural customers when their land was developed, and cooler-than-expected weather has lessened the need for landscaping water.
The audit recommended that the city examine less expensive options -- such as a water conservation program that subsidizes ``ultra low-flush'' toilets -- before expanding the recycled water system. Other efforts to encourage industrial plants to reuse their water and to staunch the flow of storm water into the sewage system also cost considerably less, the audit said.
Conservation not enough
Such conservation programs are important components but don't do enough to reduce the flow of treated wastewater into the bay. The recycled water system, on the other hand, could divert much more water and have greater environmental benefits.
Extending the recycled water system to Coyote Valley raises questions besides cost. The Silicon Valley Toxics Coalition worries that the treated wastewater contains unknown contaminants that could seep into drinking water aquifers. The water table in North Coyote Valley is much closer to ground level than in other areas the recycled water system serves.
Officials say recycled water meets clean water standards and would not pose any health threat to Coyote Valley.Still, to use recycled water for agriculture irrigation in Coyote Valley, as officials hope to do, the city or water district would have to build an advanced treatment plant there to reduce the water's salt content.