The Benefits of Adding Grind2Energy Slurry to Anaerobic Digesters.How wastewater treatment plants can become utilities of the future.

Transforming Wastewater Treatment Plants Into Utilities of the Future

Wastewater treatment plants have historically focused on protecting human

health and the environment. In fact, it’s been stated that the industry is among

the greatest accomplishments in preventing human disease. But today, there

is a significant opportunity for plants to focus on becoming utilities of the

future. How? By recovering clean water, energy, and fertilizer.

Emerson’s Grind2Energy™ food waste recycling system is a valuable

co-digestion resource in accelerating the transformation of wastewater

treatment plants into utilities of the future. Because Grind2Energy food waste

slurry is virtually contaminant free and readily biodegradable, capable water

resource recovery facilities are able to create more biogas to produce onsite

energy. They are also able to offset operational expenses by reducing their

dependence on purchased electricity. Partnering with Grind2Energy, plants

can help districts comply with landfill bans, and further exhibit environmental

stewardship by promoting green technology in the community.

Regulatory Mandates to Divert Organics From Landfills

The trend toward diverting food waste from landfills began in the European

Union where countries lack space for landfilling. Now states like Massachusetts,

Connecticut, Vermont, Rhode Island, and California are mandating similar

regulations to divert commercial organics from landfills. Cities such as Austin,

New York, San Francisco, Seattle, and Portland, Oregon are also following suit.

States soon projected to enact bans include Florida, Maryland, Minnesota,

and New Jersey.

These landfill bans are driven by high disposal costs and tipping fees, as well

as aggressive goals to reduce greenhouse gas emissions. Since states are

beginning to ban the future use of landfills, the industry needs new solutions

that are better for the environment and their communities served. Progressive

minded wastewater utilities will be looking to help their communities comply

with these landfill bans.

Fact: This place is home to Milorganite, a fertilizer made from biosolids at MMSD and

sold across the United States and Canada. Golf course superintendents and master

gardeners love the stuff!!

Grind2Energy Partners With the Milwaukee Metropolitan Sewerage District

The Milwaukee Metropolitan Sewerage District (MMSD) in Wisconsin cleans

billions of gallons of wastewater every year at two reclamation facilities that

serve 1.1 million people in 28 communities. The work done here is critical

for protecting public health, area rivers, and Lake Michigan. MMSD wants to

achieve energy neutrality with their treatment plants by 2030, and they see

food waste as an integral part of this goal.

Emerson’s Grind2Energy food waste recycling system uses an industrial-

grade foodservice grinder to turn large volumes of commercial food waste

into a pumpable slurry that’s stored in customers’ onsite tanks. The slurry

is transported to MMSD’s anaerobic digestion (AD) facility where methane

is captured and converted into renewable energy — in the form of electricity,

heat, or compressed natural gas. The rest is turned into beneficial fertilizer.

In the first quarter of 2016, Grind2Energy delivered over 200,000 gallons

of Grind2Energy slurry to the Southshore facility.

Those treatment plants currently accepting Grind2Energy food waste slurry

for co-digestion have classified it as “liquid gold.” That’s because Grind2Energy

slurry has very high volatile solids content — greater than 90 percent — and

it’s readily biodegradable. In addition to its biodegradability potential from

high volatile solids, the slurry has already gone through the first three

phases of anaerobic digestion — hydrolysis, fermentation, and acidification.

Grind2Energy slurry is “good to go” and can improve AD performance with

advanced biodegradability, and by consuming extra space within the digester.

Unlike the 20- to 30-day detention time a digester traditionally requires to

process wastewater sludge, Grind2Energy organics are converted to methane

in 5 to 10 days.*

Liquid Gold That’s Good To Go

*Adding 15% Grind2Energy Volume to Digester Improves VS Destruction Nominal Increase in Solids Production & Doubles Biogas Yield 2016 Research by George Nakhla of Western University

Grind2Energy Slurry Characteristics

• Total Solids 10-12%

• Pumpable

• Volatile Solids >90%

Grind2Energy Slurry Qualities

• Low Contamination

• High Energy Value

• Chemical Oxygen Demand ~150,000 mg/L

• Readily Biodegradable

• Synergistic Effects on Methane Production and Volatile Solids Destruction

• Very Low Impact on Biosolids Production

*Adding 15% Grind2Energy Volume to Digester Improves VS Destruction Nominal Increase in Solids Production & Doubles Biogas Yield 2016 Research by George Nakhla of Western University

Grind2Energy slurry is relatively high in solids compared to sludges pumped

into municipal digesters — about 10 to 12 percent total solids. But Grind2Energy

slurry is pumpable and contains very high volatile solids, over 90 percent on

average. The high Chemical Oxygen Demand content of Grind2Energy slurry,

and readily biodegradable composition is a result of the food waste being

held in a storage tank at the waste generator for 7 to 10 days.

Research completed at Western University by George Nakhla* has quantified

the synergistic effects of Grind2Energy slurry. For a plant currently treating

10 MGD, adding 15 percent more hydraulic load to their digesters from

Grind2Energy slurry results in a negligible solids production, yet biogas

yield is more than doubled. The research indicates co-digestion using

Grind2Energy slurry improves volatile solids destruction within digesters.

The Characteristics of Grind2Energy Slurry

Researching the Effects of Synergistic Slurry

The Economics of Adding Grind2Energy Slurry to Wastewater Utilities

With economic pressures on wastewater utilities increasing, facility managers

are looking to high-strength waste like Grind2Energy slurry to help them

become energy neutral, or even net energy producers. Adding Grind2Energy

slurry provides significant relief from operational expenses, while helping

plants demonstrate sustainability in their communities.

Additional methane leads to cost savings through reduction of purchased

energy and reduced operating costs. A typical plant spends 20 to 30 percent

of it’s budget on electricity, so reducing purchased energy frees up funds

to be used elsewhere, such as plant improvements and upgrades. The extra

money and methane can help a plant reach net neutrality, while protecting

the operation from fluctuating energy costs.

Sustainability for Wastewater Treatment Facilities is Now a Viable Option

Wastewater treatment facilities can come closer to becoming a Utility of the

Future by partnering with Grind2Energy, and recovering clean water, energy,

and fertilizer. When facilities begin to address the environmental, social, and

economic spheres of doing business, it leads to sustainability and a promising

outlook for the future. Adding Grind2Energy slurry helps facilities boost

biogas and energy production, achieve energy neutrality, reduce operating

costs, comply with landfill bans, and demonstrate environmental leadership

within the community. It’s an impactful trend that’s now worth following.

Learn more at Grind2Energy.com1-800-845-8345

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