Aero-Mod vs Jim Myers for Packaged Treatment Plants: Pros/Cons & Best-Fit Applications

Introduction

One of the most frequent points of failure in decentralized wastewater treatment is the misalignment between the chosen technology and the operational reality of the municipality. Engineers often design for steady-state compliance, overlooking the fact that small-to-mid-sized plants—ranging from 0.05 to 2.0 MGD—often face the most volatile hydraulic loading and the leanest staffing levels. When specifying packaged treatment systems, the decision often narrows down to established methodologies that diverge significantly in their approach to solids separation and biological processing.

This article provides a critical engineering analysis of Aero-Mod vs Jim Myers for Packaged Treatment Plants: Pros/Cons & Best-Fit Applications. While both manufacturers are stalwarts in the water and wastewater industry, they represent two fundamentally different engineering philosophies. Aero-Mod (Aero-Mod, Inc.) typically champions the SEQUOX (Sequential Oxidation) process paired with their ClarAtor technology, focusing on hydraulic process control and minimizing underwater moving parts. Jim Myers & Sons (JMS), while renowned for material handling and flocculation, approaches packaged solutions (often through their Mega-PAK or proprietary settling systems) with a heavy emphasis on stainless steel fabrication excellence and high-rate physical separation using plate settlers.

Understanding the distinction between these approaches is critical. A specification error here does not just mean a change order during construction; it can lead to years of struggle with sludge bulking, inability to meet emerging phosphorus limits, or excessive maintenance hours spent on mechanical drives. This guide is designed to help consulting engineers, plant directors, and utility decision-makers navigate the technical nuances of these systems, ensuring the selected equipment aligns with the facility’s hydraulic profile, effluent permits, and long-term operational budget.

How to Select / Specify

Selecting between a biological-process-heavy solution (like Aero-Mod) and a physical-separation-heavy solution (like JMS) requires a granular analysis of the plant’s constraints. The following criteria outline how to evaluate Aero-Mod vs Jim Myers for Packaged Treatment Plants: Pros/Cons & Best-Fit Applications based on engineering fundamentals rather than manufacturer brochures.

Duty Conditions & Operating Envelope

The first step in specification is defining the hydraulic and biological envelope. Small packaged plants rarely operate at “average daily flow.”

• Hydraulic Peaking Factors: Aero-Mod’s ClarAtor design utilizes a common-wall construction with surge storage capabilities within the clarifier zone itself. This is particularly advantageous for systems with high inflow and infiltration (I/I) where peaking factors may exceed 3.0 or 4.0. The clarification process relies on rapid sludge withdrawal via air lift, which can be modulated based on flow. In contrast, systems relying on JMS plate settler technology (Mega-SETTLER) offer high surface overflow rates (SOR), allowing for compact footprints, but they require careful upstream flow equalization (EQ) to prevent solids washout during peak events.
• Biological Loading (BOD/TSS): If the application requires handling variable organic loading (e.g., a municipality with significant industrial contributors or seasonal tourism), the activated sludge volume becomes critical. Aero-Mod systems typically employ extended aeration or oxidation ditch kinetics, offering high hydraulic retention time (HRT) which buffers shock loads. JMS packaged solutions can be configured for various processes, but the engineer must explicitly specify the reactor volume independent of the clarifier package to ensure adequate treatment capacity.
• Nutrient Removal Requirements: For strict BNR (Biological Nutrient Removal), specifically Nitrogen and Phosphorus, the process train is paramount. The Aero-Mod SEQUOX process creates alternating oxic and anoxic zones within the aeration basin using a programmable timer and air regulation, effectively denitrifying without separate mixing basins. If specifying JMS, the engineer typically designs the process train (A/O, A2/O) and integrates JMS components for the solid/liquid separation; however, JMS does offer integrated packages where the specific BNR strategy must be carefully defined by the process engineer.

Materials & Compatibility

The longevity of a packaged plant is dictated by its material of construction, especially in corrosive wastewater environments containing H₂S.

Read more4D-Printed Smart Materials For Water Treatment

• Concrete vs. Steel: Aero-Mod systems are frequently installed in concrete tanks (cast-in-place), where the equipment consists of the internal drop-in components (diffusers, air lifts, walkways, baffles). This is ideal for 50-year asset life planning. JMS excels in stainless steel fabrication. Their packaged plants (Mega-PAK) are often delivered as fully fabricated stainless steel (304 or 316) vessels. For sites where concrete construction is cost-prohibitive or site access is limited, the prefabricated steel approach of JMS provides significant constructability advantages.
• Corrosion Resistance: JMS is an industry leader in stainless steel manufacturing (passivation, weld quality). In applications with high salinity or aggressive industrial waste, a 316L stainless steel package from JMS offers superior resistance compared to coated carbon steel. Aero-Mod’s reliance on HDPE piping for air lifts and stainless steel structural supports also offers high corrosion resistance, but the basin itself (if concrete) must be properly protected.

Hydraulics & Process Performance

The core difference often lies in how the secondary effluent is clarified and how sludge is returned.

• Clarification Physics: Aero-Mod utilizes a rapid suction clarifier mechanism (ClarAtor). It uses air-lift pipes to vacuum sludge from the floor of the clarifier. This eliminates the need for a mechanical scraper drive and torque tubes. The advantage is hydraulic control; the return activated sludge (RAS) rate is highly adjustable. JMS often employs high-rate plate settlers (lamella). This physics relies on increasing the effective settling area. This is superior for footprint reduction but requires protection from blinding (clogging) by algae or sticky sludge.
• Energy Profiles: Aero-Mod systems generally use positive displacement or turbo blowers for both aeration and motive force (sludge return). This consolidates energy usage but means air supply is critical. JMS systems utilizing plate settlers have no moving parts in the settling zone, but sludge collection below the plates often requires a mechanical auger or hopper mechanism, which adds a mechanical drive to the energy and maintenance audit.

Installation Environment & Constructability

• Space Constraints: If the site is a retrofit with severe footprint limitations, JMS plate settler technology is often the “Best-Fit Application.” Plate settlers can handle 3x to 4x the hydraulic loading rate of a conventional clarifier, significantly reducing tank size. Aero-Mod systems, typically relying on extended aeration and conventional settling physics (even with the ClarAtor enhancement), generally require larger footprints typical of oxidation ditches.
• Constructability: For remote locations, a skid-mounted JMS unit that arrives fully piped and wired reduces on-site labor risk. Aero-Mod installations often require more significant civil works (concrete pouring) and on-site assembly of the internal mechanism, although they do offer steel tank package plants for smaller flows.

Reliability, Redundancy & Failure Modes

Engineers must evaluate what happens when components fail at 2:00 AM.

• Aero-Mod Failure Modes: The primary failure point is the blower. If the air stops, the biological process dies, and sludge return stops. However, because there are no chains, sprockets, or gearboxes underwater, mechanical jamming is virtually eliminated. Redundancy is achieved by installing standby blowers.
• JMS Failure Modes: For plate settler systems, failure modes include clogging of the plates (requiring washdown) or mechanical failure of the sludge removal auger/drive if equipped. While JMS builds robust drives, any underwater moving part has a finite MTBF (Mean Time Between Failures) lower than static pipes.

Read moreA Comparison Between Aerobic And Anaerobic Wastewater Treatment Technology

Lifecycle Cost Drivers

• OPEX (Labor): Aero-Mod typically requires less mechanical maintenance (greasing drives, tensioning chains) but may require more process oversight to balance air flow for the SEQUOX cycles. JMS plate settlers require periodic cleaning to maintain hydraulic capacity, which can be labor-intensive if an automated wash-down system is not specified.
• OPEX (Energy): Aero-Mod’s reliance on air for fluid movement is generally efficient, but air lifts are less wire-to-water efficient than centrifugal pumps for moving water. However, the elimination of mechanical drive motors offsets this. The total energy balance usually favors Aero-Mod in nutrient removal applications due to the efficient use of off-cycle aeration for denitrification.

Comparison Tables

The following tables provide a direct side-by-side analysis of the technologies. Use Table 1 for a technical feature comparison and Table 2 to determine the best application fit for your specific project constraints.

Engineer & Operator Field Notes

Real-world performance often diverges from the design data sheet. The following observations are drawn from field experience with Aero-Mod vs Jim Myers for Packaged Treatment Plants.

Commissioning & Acceptance Testing

When commissioning an Aero-Mod system, the critical path is balancing the air distribution. The “ClarAtor” relies on precise regulation of air to the suction pipes to ensure even sludge withdrawal across the floor. During the Functional Acceptance Test (FAT) or Site Acceptance Test (SAT), engineers must verify that the air header pressures are balanced and that the “squaring” of the air lift flow is accurate. If one quadrant pulls more sludge than another, you will experience localized rising sludge.

For JMS packaged plants, commissioning focuses on hydraulic leveling and seal integrity. Plate settlers rely on uniform flow distribution. If the weirs are not perfectly level (within ±1/16th inch), flow will short-circuit through a small section of the plates, causing carryover. Engineers must enforce strict leveling tolerances in the specifications. Additionally, verify the rotation and amperage draw of any sludge augers under load (simulated) before accepting the system.

Common Specification Mistakes

Leaving the SRT undefined allows manufacturers to undersize the aeration volume to reduce CAPEX. For Aero-Mod, this cripples the BNR capability. For JMS/mechanical plants, this forces the operator to waste sludge constantly to prevent blanket washouts. Always specify the minimum required aeration volume based on the coldest month wastewater temperature.

Another error is neglecting the “turndown” capability. Municipal flows fluctuate. An Aero-Mod system needs variable frequency drives (VFDs) on blowers to match air supply to biological demand, or energy costs will skyrocket. For JMS systems, verify that the inflow distribution baffles are designed to handle low-flow conditions without allowing solids to settle in the influent channels.

O&M Burden & Strategy

• Aero-Mod Strategy: The maintenance strategy is “Top-Side.” Operators never need to drain the tank to service moving parts. The focus is on the blowers and automated valves. A common O&M issue is the fouling of diffusers over 5-7 years. Specification of retrievable diffuser grids allows for cleaning without tank drainage.
• JMS Strategy: The maintenance strategy is “Cleaning & Mechanical.” Plate settlers are prone to algae growth on the upper launders and sticky sludge bridging between plates. The O&M manual must include a rigorous washdown schedule (often weekly). If the system includes a sludge screw, spare motors and gearboxes should be kept on the shelf, as lead times can be long.

Troubleshooting Guide

Symptom: High Effluent TSS.

• In Aero-Mod: Check the return sludge rate. If the air lift rate is too high, it may be disturbing the blanket. If too low, denitrification may be occurring in the clarifier, causing rising sludge (nitrogen gas bubbles). Check the timer settings on the SEQUOX cycle.
• In JMS: Check for blinded plates. If plates are clogged, the effective settling area decreases, increasing the actual overflow rate beyond design limits. Also, check for “density currents” caused by temperature differences; baffle adjustments may be required.

Design Details / Calculations

Proper sizing of these systems requires adherence to hydraulic loading limits.

Sizing Logic & Methodology

1. Surface Overflow Rate (SOR)

The critical design parameter for clarification.
Equation: SOR = Q / Area

• Conventional (Aero-Mod baseline): Typically designed for 400-800 gpd/ft² at Peak Hourly Flow. The ClarAtor can often sustain stable blankets at the higher end of this range due to rapid suction removal, but conservative design (State Standards) often dictates the lower end.
• Plate Settlers (JMS baseline): Designed based on projected surface area. Typical rates can range from 0.25 to 0.50 gpm/ft² of effective projected area. This often results in a physical footprint 25% the size of a conventional basin. However, engineers must apply a safety factor (typically 0.8) to the theoretical projected area to account for inefficiency and flow distribution issues.

2. Solids Loading Rate (SLR)

Equation: SLR = (Q + Q_RAS) * MLSS / Area

Engineers must calculate SLR at peak flow. If the SLR exceeds 30-35 lb/day/ft², the sludge blanket will rise regardless of the technology. Aero-Mod systems handle high SLR well because they can increase RAS rates instantly via air control. JMS systems with augers have a fixed maximum removal rate; verify the auger capacity (lbs/hour) exceeds the maximum predicted solids influx.

Specification Checklist

To ensure a robust bid package for Aero-Mod vs Jim Myers for Packaged Treatment Plants, include:

• Material Origin: Require “Domestic” or “AIS” (American Iron and Steel) compliance if federal funding is involved. Both manufacturers can comply, but it affects cost.
• Wall Thickness: For steel package plants (JMS), specify minimum 1/4″ or 3/8″ plate thickness. Do not accept gauge metal for structural tanks.
• Walkway Access: Specify aluminum or stainless steel grating with OSHA-compliant handrails. Access to valves (Aero-Mod) and plates (JMS) is critical. Operators will not maintain what they cannot safely reach.
• Spare Parts: Mandatory spares should include: 1 complete blower assembly (Aero-Mod), 1 set of replacement wear shoes/bearings for augers (JMS), and 10% spare diffusers.

Standards & Compliance

Reference Ten State Standards (GLUMRB) Chapter 90 (Biological Treatment). Note that Ten States generally discourages plants smaller than 100,000 gpd from using complex mechanical screens, favoring robust manual or simple auger screens. Ensure the package plant design includes specific redundancy clauses—e.g., “The treatment plant must be capable of treating Peak Daily Flow with one major unit out of service.” This often necessitates a two-train design, which impacts the footprint comparison significantly.

Frequently Asked Questions

What is the primary difference between Aero-Mod and JMS packaged plants?

The primary difference is the process philosophy. Aero-Mod packaged plants are typically biological process systems (SEQUOX) centered around their ClarAtor technology, which uses air-lift hydraulics to remove sludge without underwater moving parts. JMS (Jim Myers & Sons) packaged plants (Mega-PAK) often focus on high-efficiency physical separation using plate settler technology and stainless steel fabrication. Aero-Mod is process-driven; JMS is often clarification/fabrication-driven.

Which system is better for nutrient removal (BNR)?

Generally, Aero-Mod is more inherently suited for Biological Nutrient Removal (BNR) in a single package. The SEQUOX process is designed to cycle aeration on and off to create oxic and anoxic conditions for nitrogen removal and biological phosphorus uptake. JMS systems can achieve BNR, but the process engineering (zones, recycle pumps, mixers) must be explicitly designed and integrated into the tankage, whereas it is a standard native feature of the Aero-Mod design.

How does the maintenance cost compare between the two?

Aero-Mod typically has lower mechanical maintenance costs because there are no chains, sprockets, or bearings underwater; maintenance is focused on blowers and air valves. However, diffuser replacement (every 5-10 years) is a cost. JMS systems with plate settlers require regular washing to prevent clogging (labor cost) and maintenance of any mechanical sludge collectors (augers/drives). Over a 20-year lifecycle, Aero-Mod often shows lower parts replacement costs, while JMS may offer lower civil/construction costs.

Are plate settlers (JMS) approved by all state regulators?

Most states accept plate settlers, but often with caveats regarding the “effective” surface area credit. Some regulators (e.g., specific DEP/DNR offices) may only allow credit for 80% of the plate area or require upstream fine screening (2mm or 3mm) to prevent clogging. Always consult the local regulatory authority before specifying plate settlers for raw wastewater applications.

Can these systems handle high inflow and infiltration (I/I)?

Aero-Mod’s ClarAtor has a slight edge in high I/I applications due to its common-wall surge storage capacity and ability to rapidly increase sludge return rates using air. JMS plate settlers are sensitive to hydraulic surges; if the flow exceeds the design surface overflow rate, solids can wash out quickly. If JMS is selected for a high I/I community, significant upstream flow equalization is recommended.

What is the typical lifespan of these packaged plants?

An Aero-Mod system installed in a concrete basin has a 50+ year structural life, with equipment refreshes every 15-20 years. A JMS stainless steel package plant typically has a lifespan of 25-40 years depending on the chloride content of the water and the grade of stainless steel (304 vs 316). Carbon steel package plants (from other competitors) typically last 15-20 years; both Aero-Mod and JMS offer superior longevity to standard carbon steel.

Conclusion

When evaluating Aero-Mod vs Jim Myers for Packaged Treatment Plants: Pros/Cons & Best-Fit Applications, the engineer’s role is to match the technology to the operator’s reality. If the municipality has a limited staff that struggles with mechanical repairs but understands biological basics, Aero-Mod’s lack of underwater moving parts is a decisive advantage. The SEQUOX process offers a forgiving biological safety factor that protects against permit violations during load swings.

Conversely, for industrial applications, retrofits in urban areas, or sites where excavation is difficult or costly, the JMS Mega-PAK and plate settler technology offer an engineered density that conventional systems cannot match. The superior stainless steel fabrication of JMS ensures that even a steel tank solution provides municipal-grade longevity.

Ultimately, there is no “bad” choice between these two premium manufacturers, only a “misapplied” choice. By rigorously analyzing the hydraulic profile, nutrient targets, and available labor hours, engineers can specify the system that yields the lowest total cost of ownership and the highest reliability for the specific application.