Case Study: Floating Lateral Fine Bubble Pilot

Mainsail Global worked with an industrial customer to install an operational research and development pilot floating lateral fine bubble aeration unit. Purpose of the pilot test was to demonstrate fine bubble flexible membrane technology that could operate satisfactorily year-round (throughout the entire industrial production cycle of September through May) in the current waste stream in a predictable, reliable, and cost effective manner.  Final recommended design for applying fine bubble aeration was optimized to minimize capital investment and maximize treatment.

Understanding the proper material to use for the fine bubble flexible membrane was a key activity at the facility.  Mainsail Global initiated a Field Test Unit program to understand the dynamics of the water chemistry and determine the optimal material for the application as well as quantify impact of operation on efficiency and better understand maintenance requirements.

System reliability and robustness, compliance, flexibility to meet changing process requirements, and predictability of operation, and overall reliability of system performance and cost were the basis of Customers goals.  The Customer must guarantee the wastewater treatment systems ability to treat the waste stream so as not to impact or shorten the industrial manufacturing cycle.

With the current wastewater treatment system components, increased volume throughput of the plant and varying quality of product processed, the Customer cannot guarantee this with any confidence with the current treatment process.

Specific strategic goals and objectives included:

Better treatment with zero down time

Predictability of the system

  • H2S standard - compliance
  • Ability to address high TSS due to algae blooms
  • Must pass wet test (minnow trap - minnows in waste stream prior to discharge, can't kill the minnows)
  • Ability to address ammonia
  • Minimize requirements for plant personnel to operate and maintain
  • Control Odor without use of perfume system (eliminate need for costly operation)
  • Predictable in terms of system performance, capacity, and ability to meet effluent quality standards
  • Predictable in terms of cost to operate and maintain
  • Operational metric for evaluation of cost to operate and maintain per cubic meter of water treated and resultant effluent quality
  • Ability to discharge on a continuous, as needed, predictable basis; high quality effluent Better water quality for reuse of water in the process

System life of fifteen - twenty years

  • Routine Maintenance program to ensure efficient and compliant operation
  • Operational analytics to maximize system life and maintenance activities

There were multiple skills and activities required as part of development of a total solution for the Customer to achieve the desired strategic goals and objectives.

Key Activities included:

Proper overall system design

Testing and Analytics

  • Understanding of overall plant flow, influent, desired discharge quality, etc.
  •  Defining and quantitative specifications
  • Water quality - Confirm proper membrane and materials of construction
  • System performance on an ongoing basis- Permanent Field Test Unit

Membrane Specification

System Specification

  • Ensure long-term operation and performance (DWP and OTE)
  • Designed to meet process and material requirements

Maintenance Program


  • Scheduled activities to ensure proper system operation to meet strategic goals and objectives
  • Proactive maintenance of system performance to ensure predictability (operation and cost) and reliability (capability to provide proper treatment)
  • Material and workmanship

Typical Plant Info

  • Flow (Average) 7.6 mgd
  • Influent BOD⁵ ≥ 1,000 mg/L Discharge Limit BOD⁵ 25 mg/L
  • Influent COD 2,400 mg/L

System had to operate in temperatures of less than 32° F on a continuous basis throughout the winter months.

Another Financial Case Study: Improper Design

(excess air capacity)

Below is an actual financial proposal summary that Mainsail Global put together for a client who operated a manufacturing plant currently utilizing surface aerators. They received another bid to simply replace existing/add new aerators (I.e., throw excess oxygen at the problem) to solve some biological issues they were experiencing. Mainsail Global, on the other hand, further investigated the issues and recommended two different fine bubble options that provided sufficient oxygen and at a cost savings of well over $1MM over the course of the client's 10-year capital depreciation period.

Surface Aerator Solution

Fine Bubble Solutions

(7-40 HP)

Automated Pre-Treatment

Manual Pre-Treatment

Lbs. O2 / day

Lbs. O2 / cycle (annual)

Percent Decrease









Initial Investment Cost




Depreciation Cost

Energy Cost

Maintenance Cost










Total Operation Cost




Cost$ / lb O2 (w/depreciation)




Cost$ / lb. O2 (w/o depreciation)




Energy and Operations Cost Analysis

Annual Energy Cost

Annual Operation Cost









Fine Bubble Auto

Fine Bubble Manual



Fine Bubble Auto

Fine Bubble Manual

10 year Total Savings and Pay-back Period

10 year Total Cost Savings

Initial Investment Payback Period (years)








Fine Bubble Auto

Fine Bubble Manual



Fine Bubble Auto

Fine Bubble Manual


Initial Investment

Pay-back Scenario

Incremental $39k

Pay-back Scenario


  • Re-coup initial investment of $459k (Fine Bubble Auto Solution)
  • 2.8 years to re-coup
  • Yields NET SAVINGS of $1.1MM (7 years * $160k)
  • $459k vs. $420k (incremental $39k) -Decision to choose FB Auto vs. Surface Aerator (already committed to doing something)
  • Payback in LESS THAN TWO MONTHS (FB Auto solution yields a $160k per year/cycle savings).
  • Lower total non-depreciation operations cost to one-third of SA solution ($.06 vs $.02)
  • Efficiency savings (over 10-year depreciation period) of: $1.6MM - 9.8 years * $160k
  • Spend $39k more in initial investment (FB Auto) than baseline option (SA) and receive $1.6MM in cost/efficiency savings (10-yr depreciation period)

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