WHY LOCI CONTROLS?With financial, operational, environmental, health, and safety benefits, Loci Controls’ products and services help optimize facility management and gas collection for operators and landfill owners alike.

INCREASE REVENUEMaximize methane flow

Control N2 in the wellfield

Automated valve adjustments

Better collection system efficiency

Reduce plant downtime

INCREASE PRODUCTIVITYFor both plant and employees

Lower labor costs for wellfield tuning and O&M

Reduce plant maintenance costs

REDUCE ENVIRONMENT HEALTH & SAFETY RISKS

Reduce man hours spent in wellfield

Reduce fugitive gas emissions

Reduce odors

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Loci uses both gas chromatography data from the entire wellfield and individual collection well readings to optimize the landfill gas collection process.

Loci connects directly to the plant gas chromatograph (“GC”) via a serial port or Sentry and uses real-time gas composition and energy content (BTU) to ensure that measured nitrogen and oxygen meet process set points and allow the operator to stay in the pipeline.

When the BTU value at the GC approaches either the high or low limits of a desired process set point range, Loci’s automated system makes batch valve adjustments in the wellfield to stabilize the BTU values keeping them within the optimal range.

Adjustments to valve positions on each individual collection well are weighted by gain factors which reflect how responsive an individual well’s gas composition is to a given valve adjustment. For some collection wells, small valve adjustments have a large impact on gas composition; for other collection wells, larger valve adjustments are required to change the gas quality.

The manual well tuning method only relies upon data at each individual well and generally, adjustments can be made only one well at a time; at a maximum the number of simultaneous adjustments possible is limited by the number of wellfield technicians deployed.

In contrast, Loci’s automated landfill gas collection system can make simultaneous changes on a large number of wells in response to changing gas composition as measured at the plant.

HOW LOCI CONTROLS’ AUTOMATED GAS COLLECTION VARIES FROM MANUAL TUNING

TECH NOTE

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Loci automated gas collection: Fine Tuning Algorithm

Loci’s original automated gas collection algorithm uses frequent (hourly) gas composition and flow measurements at each collection well to make small incremental valve adjustments. This automatic “fine tuning” of each collection well results in optimized CH4 flow, while maintaining individual well gas composition requirements within balance gas (N2) and O2 thresholds.

Loci’s fine tuning automation is a continuous “process cycle” that optimizes individual well and overall gas collection.

1. The Loci Controllers and Guardians are used to take individual collector readings (gas composition, flow, LFG temperature, ambient pressure, pressure above and below Loci’s automated valve, and valve position).

2. In stable environmental conditions, automation is used to make small, incremental valve adjustments (less than 1% open or closed based on the last measurement).

3. The Loci unit will take another gas composition reading and confirm the relative effect of the change both on gas composition and flow – (i.e did CH4 flow increase while still meeting gas composition requirements?).

4. Based on the results of the last reading, the unit will make a corresponding valve adjustment in the same or opposite direction (i.e. valve open or closed).

5. Lastly, the cycle repeats to continuously seek the maximize CH4 flow, while limiting N2 and O2 in the landfill gas.

Loci’s fine tuning algorithm is like having a well field technician stationed at each collection well 24/7/365, manually implementing the “process cycle” as described above.

(617) 575.2716 sales@locicontrols.com www.locicontrols.com

Loci’s Dynamic Response Algorithm: Automation at an individual well level that allows for well tuning based on known response of wells to external factors that affect the gas collection system

LFG to high- BTU landfill gas collection systems and individual collection wells respond uniquely to changes in external conditions, most notably barometric pressure and ambient temperature.

Loci’s real time monitoring of each collection well, including measurement of ambient conditions (barometric pressure and temperature), allows Loci to characterize the response of each collection well to changes in external conditions.

Loci’s dynamic response algorithm uses individual collection well gain factors to proactively make valve adjustments based on changing external conditions, before waiting to measure the resulting changes to gas composition.

(617) 575.2716 sales@locicontrols.com www.locicontrols.com

Loci Automated Gas Collection: Using the three algorithms outlined above, Loci maximizes CH4 Flow while keeping Nitrogen below 1% concentration in the landfill gas, O2 below .10% (1000 ppm), and delivers to the sales pipeline gas with a minimum of 965 BTU.

Here are process limits for the four LFG to high BTU projects where Loci automated gas collection is increasing revenue while controlling 80%-100% of the total LFG collection system flow:

Project 1 Kansas

Project 2 Michigan

Project 3 Texas

Project 4 Oklahoma

Gas specifications

Plant Inlet

Oxygen % 0.20% 0.12% 0.12% 0.10%

Nitrogen % - 1.30% 1.00% -

Plant Outlet

BTU 950 965 950 950