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Besides saving the environment Manteca saving money in long run
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Senior city engineer Bret Swain, left, and Public Works Director Mark Houghton, inspect part of the food waste to fuel facility being installed at the wastewater treatment plant. - photo by DENNIS WYATT

It’s all about the green when it comes to what you place in your carts for Manteca’s municipal solid waste crews to collect each week.

But that’s not just green as in trying to be as environmental friendly as possible. It’s also about saving Manteca’s ratepayers greenbacks.

Being green and saving green are the driving forces behind the food waste to fuel project being constructed at the city’s water treatment plant as well as a bid process now underway to install a massive solar farm to provide most of the electricity for the treatment process.

“One of our goals is to keep costs down in the long run,” Public Works Director Mark Houghton said.

That is on top of ever tighter standards dictated by state in regards to water quality, air quality, what is buried at landfills, and water use.

And while the city is in the middle of getting the food waste to fuel up and running — the first solid waste trucks will likely be running on energy created from pizza scraps and leftovers as well as what you flush down the toilet by mid-2019 — they are already looking down the road for the next money saver that also doubles as a green initiative to help to comply with coming state laws.

Within five years, Houghton anticipates the city being in the position to start planning for eventually creating compost from yard waste as well as household organic waste that includes food as well as newspaper and other paper products. Staff believes such a facility could be developed at the wastewater treatment plant. It would not only take what is collected currently from green carts as well as shred household food waste and paper, but they will also be able to mix in dried out sludge from the wastewater treatment process instead of landfilling it.

What Manteca

gains from the

process besides

treating wastewater

If that happens and the city has its other endeavors up running from the solar initial to food waste to fuel Manteca ultimately:

avoids landfilling the vast majority of solid waste that Manteca residents and businesses generate.

will produce ample compost for city needs as well generate compost for commercial use.

will have recycled wastewater available for construction dust control when water supply conditions tighten.

will reduce air pollution by almost eliminating the need to burn off methane gas at the wastewater treatment plant plus replace diesel with compressed biogas to power municipal solid waste trucks.

will slash the city’s wastewater treatment plant PG&E to a fraction of the annual bill that is now in excess of $1.4 million.

will stabilize energy costs to take a significant pressure off rates for wastewater customers.

will avoid landfill costs that are now at $52 a ton but are expected to escalate significantly as existing landfill space is filled in the coming 10 to 25 years.

Manteca is able to make the food waste conversion to fuel work as well as other green initiatives designed to reduce long-range costs because unlike neighboring cities it retained control of both solid waste and wastewater operations by electing not to privatize either service. At the same time the municipal wastewater treatment plant as expanded and redesigned makes putting a food waste conversion facility in place feasible.

“We have options to do a number of things because Manteca is a full service city,” Houghton noted.

When it comes to not contracting out key municipal services to private vendors or other agencies Manteca is in a very small group among California’s 482 municipalities. Not only does Manteca run its own wastewater and solid waste operations but it also has its own water system and well as police and fire departments.

Solid waste operations

will shift to treatment plant

The next step in the food waste to fuel will be shifting the solid waste yard and office to the treatment plant.

That’s because slow fills are needed to maximize the PSI (pounds per square inch) of compressed biogas needed to power heavy trucks. The solid waste fleet would have their tanks filled overnight.

Houghton noted there will be a public component meaning private citizens and businesses will be able to purchase compressed natural gas via a quick fill pump at the wastewater treatment facility.

Having adequate material to generate compressed biogas won’t be an issue.

Other nearby jurisdictions have expressed interest in bringing food waste to the Manteca plant.

The project includes the ability to accept FOG — the acronym for fat, oil and grease — from restaurants and such that is currently shipped to a recycler in Oakland.

Food waste to fuel

addresses other mandates

besides diverting waste

from being landfilled

State law requires all jurisdictions to divert 75 percent of all organic waste — essentially green yard waste and food waste — from being buried in landfills by 2020. That diversion number jumps to 90 percent by 2025. The city is already recycling green waste. It has also started requiring some schools, restaurants, and supermarkets to separate food waste from the rest of their garbage. Ultimately all significant commercial, school, or institution (such as a hospital) of food waste will need to recycle it. The 90 percent diversion goal will require residential food waste recycling. That could be accomplished via the compost strategy.

The California Air Resources Board requires all jurisdictions and trucking firms to switch to cleaner burning engines. That means 16 solid waste refuse trucks that can cost $350,000 to $500,000 apiece have to be purchased by 2023. The fuel to run those trucks will come from the wastewater treatment plant.

And earlier this month the state mandated all buses purchased in California starting in 2029 must have zero emissions. That mandate also requires all buses on the road by 2040 to be clean burning.

Houghton said not only would future city buses rely on the clean fuel that will be generated at the wastewater treatment plant, but so could those that Manteca Unified School District will need to acquire.

Another way of

generating green

Under a federal law in place since 2007, Manteca can assign what’s called a Renewable Identification Number (RIN) to the biofuel they create. Those RINs constitute credits that oil companies purchase so they meet a federally mandated goal that a percentage of their fuel production is biofuels.

The city — in recognizing that the heaviest truck that goes down most residential streets in Manteca during any given week is a municipal solid waste truck —has identified street repair as a legitimate expense for cost recovery in municipal garbage rates. The rate hike that was adopted “suspends” the charge. Instead the city will funnel money it receives from oil companies from the sale of the RIN credits generated by creating biofuel from food waste to the street division.  

Underscoring how cutting edge the Manteca undertaking is, upwards of 300 professionals in the solid waste and wastewater fields will be touring the city’s operation next year.