A Buyer’s Guide to Purchasing Soil-Remediation Equipment

Purchasing soil-remediation equipment is a significant project decision. The selected system must support the remediation strategy, operate under actual site conditions, meet treatment and discharge requirements, and remain serviceable throughout the project.

A successful purchase begins with a clear design basis. Airflow, vacuum, contaminants, moisture, utilities, treatment objectives, controls, site access, and anticipated operating duration should all be evaluated before equipment is ordered.

What Is Soil-Remediation Equipment?

Soil-remediation equipment is used to remove, capture, treat, or destroy contaminants found in soil, soil gas, groundwater, or related process streams.

Depending on the remediation method, a complete system may include:

• Soil vapor extraction blowers
• Vacuum pumps or high-vacuum extraction equipment
• Air-injection or air-sparging packages
• Moisture separators and knockout tanks
• Particulate filters
• Thermal or catalytic oxidizers
• Electric catalytic oxidizers
• Activated carbon vessels
• Groundwater treatment equipment
• Air strippers and water-transfer pumps
• Ozone or oxygen-injection systems
• Control panels, instruments, alarms, and safety devices
• Piping manifolds, valves, silencers, and discharge stacks
• Skids, trailers, enclosures, or equipment buildings

These components must work together. A blower that can produce the required vacuum may not be appropriate if the downstream treatment equipment creates excessive pressure loss. An oxidizer may be properly sized for airflow but unsuitable for the contaminant mixture. A carbon system may provide adequate initial treatment but become expensive if contaminant loading is underestimated.

Begin with the Remediation Strategy

Equipment selection should follow the remediation design rather than determine it. Before requesting equipment quotations, the project team should define what the system is intended to accomplish.

Common soil-remediation approaches include:

• Soil vapor extraction
• Air sparging combined with vapor extraction
• Bioventing
• Dual-phase or multiphase extraction
• Vacuum-enhanced product recovery
• In-situ thermal treatment with vapor collection
• Ozone or oxygen injection
• Groundwater extraction and aboveground treatment

Each approach creates different equipment requirements. A conventional soil vapor extraction system may need a moderate vacuum blower, moisture separation, and off-gas treatment. A multiphase extraction project may require higher vacuum, liquid handling, additional separation equipment, and more complex controls.

1. Characterize the Contaminants

The contaminant profile is one of the most important parts of the equipment design basis.

The equipment supplier should be given information about:

• Each known contaminant of concern
• Expected average concentrations
• Expected maximum concentrations
• Possible concentration changes during operation
• Petroleum hydrocarbons or fuel-related compounds
• Chlorinated or halogenated compounds
• Potential catalyst poisons or carbon-loading concerns
• Presence of separate-phase product
• Moisture, particulates, corrosive compounds, or condensable vapors

A treatment technology that works well for one contaminant stream may not be appropriate for another. The contaminant mixture affects the choice between thermal oxidation, catalytic oxidation, activated carbon adsorption, condensation, specialty media, or a combination of treatment methods.

The system should be designed for the highest credible loading condition, not simply the concentration measured during one sampling event.

2. Establish the Required Airflow

Soil vapor extraction and vapor-treatment equipment is commonly sized according to airflow, typically expressed in cubic feet per minute, or CFM.

The required airflow may be estimated from pilot testing, well testing, subsurface modeling, prior site data, or the anticipated number of extraction wells operating at the same time.

The design should identify:

• Normal operating airflow
• Minimum controllable airflow
• Maximum anticipated airflow
• Airflow required at individual extraction wells
• Potential future expansion
• Expected dilution-air requirements
• Airflow changes caused by seasonal or subsurface conditions

Oversizing is not always beneficial. A severely oversized blower may operate inefficiently, provide poor control at lower flow rates, or create unnecessary electrical and equipment costs.

Undersizing can prevent the system from reaching the required airflow at the extraction wells and may limit the effectiveness of the remediation process.

3. Determine the Required Vacuum

Airflow and vacuum must be evaluated together. A system capable of moving the required airflow at low resistance may not produce the same airflow when connected to extraction wells, long piping runs, moisture separators, filters, valves, and treatment equipment.

The design vacuum should account for the complete system, including:

• Vacuum required at the extraction wells
• Losses through headers and conveyance piping
• Moisture-separator pressure loss
• Filter and carbon-vessel pressure loss
• Oxidizer or treatment-system resistance
• Valves, silencers, flame arrestors, and fittings
• Changes in pressure loss as filters or media become loaded

Low-, medium-, and high-vacuum systems serve different site conditions. The appropriate blower or vacuum technology should be selected from an actual operating point rather than from a maximum-flow rating shown on a product sheet.

4. Select the Off-Gas Treatment Method

Extracted soil vapors may require treatment before discharge. The appropriate treatment method depends on contaminant type, concentration, mass loading, airflow, moisture, regulatory requirements, utilities, and operating cost.

Activated carbon filtration

Activated carbon adsorbs VOCs onto filtration media. Carbon systems may be relatively simple to operate and can be effective for suitable contaminant streams.

Buyers should consider carbon usage, vessel size, lead-and-lag configuration, monitoring requirements, expected change-out frequency, transportation, and spent-media management.

Thermal oxidation

Thermal oxidizers use elevated temperature to destroy organic contaminants. They may be appropriate for vapor streams with substantial contaminant loading, changing concentrations, or compounds that are unsuitable for a catalyst.

The purchase evaluation should include burner capacity, fuel requirements, combustion controls, heat recovery, safety interlocks, discharge-stack requirements, and expected operating temperature.

Catalytic oxidation

Catalytic oxidizers use a catalyst to permit oxidation at a lower temperature than conventional thermal oxidation.

Buyers should verify that the contaminant stream is compatible with the catalyst and consider catalyst inspection, cleaning, replacement, temperature control, and protection from moisture, particulates, and catalyst-deactivating compounds.

Electric catalytic oxidation

An electric catalytic oxidizer may be considered when sufficient electrical power is available, natural gas is unavailable, or an electrically heated package is otherwise preferred.

The electrical service, connected load, utility costs, controls, and site power limitations should be reviewed before selecting this option.

Combined treatment systems

Some projects benefit from a treatment train rather than one treatment technology. Carbon may be used for polishing, backup, startup, or temporary treatment. A project may also transition from one treatment method to another as contaminant concentrations decrease.

5. Plan for Moisture and Entrained Liquids

Soil vapor extraction systems frequently pull water vapor, condensation, groundwater, or other liquids into the aboveground equipment.

An entrained-liquid separator or moisture knockout tank can help protect the blower and treatment system. The separator may require:

• Automatic high-level shutdown
• Level indicators or switches
• Manual or automatic draining
• Transfer pumps
• Secondary containment
• Sample ports
• Cold-weather protection
• Connections to a liquid-treatment system

The expected liquid volume should be estimated during system design. A separator that is too small or difficult to drain can create frequent shutdowns and increase field-service requirements.

6. Confirm Available Utilities

The site’s available utilities may eliminate certain equipment options or require costly infrastructure improvements.

Confirm the following before placing an order:

• Available voltage and electrical phase
• Maximum electrical service capacity
• Natural-gas availability and delivery pressure
• Propane availability when natural gas is not present
• Water supply and drainage
• Compressed-air requirements
• Internet or cellular connectivity for remote monitoring
• Backup power or automatic restart requirements

Ask for the equipment’s complete electrical load rather than only the blower motor horsepower. Heaters, control transformers, pumps, cooling equipment, ventilation fans, tracing, lighting, and auxiliary equipment may add to the connected load.

7. Define the Control-System Requirements

A remediation system may operate at a remote location for months or years. The control system should make the equipment safe, understandable, and practical to operate.

Possible control features include:

• Main power disconnect and emergency stop
• Automatic startup and shutdown sequences
• Variable-frequency drives
• Airflow, pressure, vacuum, and temperature displays
• Combustible-gas or lower-explosive-limit monitoring
• High-temperature and flame-failure shutdowns
• High-liquid-level shutdowns
• Filter or vessel differential-pressure monitoring
• Alarm history and operating-hour meters
• Data logging
• Remote alarm notifications
• Remote monitoring or control
• Automatic restart following power interruption

The buyer should identify which operating data must be recorded for compliance reports, performance evaluation, maintenance planning, and project optimization.

8. Consider the Installation Site

Equipment that works well in a manufacturing facility may require modifications for a remote remediation site.

Review site conditions such as:

• Available equipment footprint
• Truck and crane access
• Forklift-access requirements
• Terrain and foundation conditions
• Indoor or outdoor installation
• Weather exposure
• Ambient-temperature range
• Flooding or drainage concerns
• Noise restrictions
• Nearby residences or occupied buildings
• Hazardous-location electrical requirements
• Security and vandalism concerns

Skid-mounted, trailer-mounted, enclosed, and permanently installed systems each have advantages. The best arrangement depends on mobility, project duration, permitting, access, maintenance, and protection from weather.

9. Evaluate Materials and Construction Quality

Remediation equipment may operate continuously in difficult conditions. Construction quality can affect reliability, corrosion resistance, maintenance cost, and equipment life.

When reviewing a proposal, consider:

• Skid and frame construction
• Materials used for process piping and vessels
• Exterior coatings and corrosion protection
• Weatherproofing of electrical components
• Accessibility of filters, drains, valves, and instruments
• Quality of piping supports and vibration isolation
• Protection of exposed instruments and tubing
• Labeling of components, wiring, and flow direction
• Availability of lifting points or forklift pockets

The lowest initial price may not provide the lowest project cost if the equipment is difficult to maintain or requires frequent repairs.

10. Review Maintenance and Serviceability

Routine maintenance should be considered during the purchasing process rather than after the equipment arrives.

Ask the supplier:

• Which components require routine maintenance?
• How frequently should filters, belts, bearings, or oil be serviced?
• Can major components be accessed without removing other equipment?
• Are replacement parts readily available?
• Are proprietary parts required?
• Which spare parts should be purchased with the system?
• Is telephone troubleshooting available?
• Are field-service technicians available?
• Can the supplier provide startup and operator training?

A well-designed system should provide safe access to components and make common maintenance procedures straightforward.

11. Calculate the Total Cost of Ownership

Equipment price is only one part of the system’s total ownership cost.

A complete cost evaluation should include:

• Initial equipment purchase
• Engineering and customization
• Freight and delivery
• Unloading, rigging, and installation
• Electrical and utility connections
• Permitting and emissions testing
• Fuel and electrical consumption
• Carbon, filters, catalyst, and other consumables
• Routine preventive maintenance
• Replacement parts
• Sampling and laboratory analysis
• Spent-media transportation and management
• Field-service labor and travel
• Cost of equipment downtime
• Future modifications or capacity increases

Energy use and consumables can exceed the original equipment cost over a long project. Buyers should request operating estimates based on expected site conditions whenever sufficient design information is available.

12. Compare Standard and Custom Equipment

Standard equipment can reduce engineering time, manufacturing cost, and delivery complexity. It may also simplify replacement parts and operator training.

Custom engineering may be justified when a project has unusual airflow, vacuum, pressure, contaminants, space limitations, controls, utilities, or permitting requirements.

Common customizations include:

• Custom blower or vacuum-pump selection
• Special vessel materials
• Integrated oxidizer and extraction packages
• Carbon-vessel manifolds
• Custom control panels and data logging
• Noise-control enclosures
• Trailer-mounted or containerized systems
• Heat tracing and freeze protection
• Remote telemetry
• Additional safety interlocks
• Integration with existing site equipment

The buyer should distinguish between necessary customization and features that add cost without improving treatment performance or reliability.

13. Request Complete Documentation

Documentation is essential for installation, permitting, operation, maintenance, troubleshooting, and future modification.

A complete equipment package may include:

• Equipment arrangement drawings
• Process-flow diagrams
• Piping and instrumentation diagrams
• Electrical schematics
• Control-panel drawings
• Utility requirements
• Equipment data sheets
• Operating and maintenance manuals
• Recommended spare-parts list
• Startup and shutdown procedures
• Alarm and troubleshooting information
• Manufacturer literature for major components
• Inspection or testing records

Documentation requirements should be listed in the purchase order so they are included in the project schedule.

14. Evaluate the Equipment Supplier

The supplier’s experience can be as important as the equipment specifications.

Consider whether the supplier can:

• Review pilot-test and site-design information
• Provide complete integrated remediation systems
• Explain the proposed operating point
• Identify assumptions and equipment limitations
• Provide realistic utility and maintenance requirements
• Customize equipment when necessary
• Provide startup and operator training
• Supply spare and replacement parts
• Provide field service after installation
• Support future system modifications

A technically complete proposal should explain what is included, what is excluded, and which project information still requires confirmation.

Common Purchasing Mistakes

• Selecting equipment by maximum CFM alone: The required airflow must be evaluated at the required vacuum and total system resistance.
• Using only average contaminant concentrations: Startup and peak concentrations may be much higher than later operating conditions.
• Ignoring moisture: Condensate can damage blowers, increase carbon usage, interfere with treatment, and cause frequent shutdowns.
• Underestimating utility requirements: Electrical, natural-gas, propane, and auxiliary loads should be verified before equipment is delivered.
• Buying unrelated components separately: Components may not operate correctly when connected as a complete treatment system.
• Focusing only on purchase price: Energy, consumables, maintenance, downtime, and field service can have a larger long-term impact.
• Overlooking service access: Filters, valves, instruments, catalyst cells, and blower components must be accessible for maintenance.
• Waiting too long to address permits: Air-discharge, electrical, building, noise, and site-specific requirements may affect the equipment design.

Information to Include in a Request for Proposal

Providing complete information helps equipment manufacturers prepare a more accurate proposal.

1. 1. Project location: Include climate, elevation, installation environment, and applicable site restrictions.
2. 2. Remediation method: Identify soil vapor extraction, air sparging, multiphase extraction, groundwater treatment, or another process.
3. 3. Contaminants: List all known compounds and expected concentration ranges.
4. 4. Required airflow: Provide normal and maximum CFM.
5. 5. Required vacuum or pressure: State the required operating point and where it is measured.
6. 6. Moisture and liquids: Describe expected condensate, groundwater, product, solids, and liquid-handling requirements.
7. 7. Treatment objective: Provide required outlet concentrations, destruction efficiency, or discharge limits when available.
8. 8. Utilities: List available electrical service, natural gas, propane, water, compressed air, and communications.
9. 9. Control requirements: Identify alarms, data logging, remote monitoring, and automatic operating requirements.
10. 10. Equipment configuration: Specify skid-mounted, trailer-mounted, enclosed, indoor, outdoor, portable, or permanent installation.
11. 11. Schedule: Include desired drawing, manufacturing, delivery, startup, and operating dates.
12. 12. Required services: Identify installation support, startup, training, testing, maintenance, and field-service needs.

Purchase, Rent, or Begin with a Pilot Study?

Purchasing is often appropriate for long-term projects, recurring remediation work, permanent treatment installations, and systems requiring substantial customization.

Rental equipment may be useful when the project duration is short, operating conditions are still uncertain, equipment is needed quickly, or the treatment method may change as concentrations decline.

A pilot study can provide valuable information about achievable airflow, vacuum response, contaminant concentrations, moisture production, mass-removal rates, and treatment requirements before a permanent system is purchased.

How Mako Industries Can Help

Mako Industries designs, manufactures, sells, rents, and services environmental remediation equipment for soil, vapor, and water treatment applications.

Available equipment includes:

• Gas-fired thermal and catalytic oxidizers
• Electric catalytic oxidizers
• Low-, medium-, and high-vacuum extraction packages
• Vapor extraction and air-injection systems
• Carbon-filtration vessels and treatment media
• Groundwater-treatment systems
• Air strippers and carbon-adsorption systems
• Ozone and oxygen-injection systems
• Packaged skids, manifolds, controls, and custom-engineered systems
• Replacement parts, field service, startup, and training

Mako Industries can work with environmental consultants, remediation contractors, property owners, and project managers to review operating requirements and develop an equipment package suited to the project.

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