Erma First BWTS Overview (FIT and BLUEGUARD)

Updated 2026-06-16

Greek manufacturer Erma First offers ballast water treatment across two main platforms: the FIT system combining filtration with full-flow or side-stream electrolysis, and the newer BLUEGUARD side-stream electrochlorination design optimised for compact footprint and low power. Both deliver the IMO D-2 standard through filtration and TRO-based disinfection with neutralization on discharge, and both carry IMO and USCG type approval.

Erma First BWTS Overview (FIT and BLUEGUARD)

Key takeaways

Erma First offers the FIT filtration-plus-electrolysis system and the newer compact BLUEGUARD side-stream electrochlorination design.
Both platforms use a 40 to 50 micron self-cleaning filter on uptake ahead of electrolytic disinfection.
BLUEGUARD electrolyses only a side-stream at high concentration, keeping the cell and rectifier compact and reducing power demand.
As electrolytic systems, performance is salinity dependent and limited in fresh or brackish water without salt dosing.
TRO monitoring controls dosing and discharge, with sodium thiosulfate neutralization before overboard discharge.
Both platforms hold IMO and USCG type approval and require MEPC.325(75) commissioning testing once installed.
Filter screens and electrodes are the principal consumables, available with reagents and service through Sea Clean AS.

Erma First's Two Platforms

Erma First entered the ballast water market with the FIT (Filtration Independent Treatment) system, which couples an automatic backwashing filter with electrolytic disinfection. After acquiring other treatment portfolios and consolidating its range, the company developed BLUEGUARD as a next-generation side-stream electrochlorination system designed to reduce footprint, power demand and installation complexity.

Both platforms follow the now-standard architecture for electrolytic systems: mechanical filtration removes sediment and larger organisms on uptake, while an electrolysis stage generates total residual oxidant to inactivate the remaining biology. The choice between full-flow and side-stream electrolysis affects power draw, equipment size and how dose is controlled, but the compliance target is identical.

BLUEGUARD's side-stream approach electrolyses only a small fraction of the flow at high concentration and injects that oxidant-rich stream back into the main ballast line, which keeps the electrolysis cell and rectifier compact relative to a full-flow chamber sized for the whole ballast pump capacity.

Filtration Stage

On uptake the ballast first passes an automatic self-cleaning screen filter, generally in the 40 to 50 micron class, removing sediment, larger zooplankton and suspended solids. Backflushing is triggered by differential pressure across the screen, with the backwash returned to the area of uptake so concentrated organisms and sediment are not transported to a new location.

Filtration reduces the organism and solids load reaching the electrolysis stage, which both improves disinfection efficiency and lowers oxidant demand. The filter is also the most maintenance-intensive component, with screen elements, drive mechanisms, seals and differential-pressure instrumentation forming the bulk of the wear-part inventory.

Filtration is normally applied on ballasting only; on deballasting the water typically bypasses the filter and passes through the neutralization stage before discharge, having already been treated and held during the voyage.

Electrolysis, TRO and Salinity

The disinfection stage generates TRO by electrolysis, so like all electrolytic systems it depends on adequate salinity and conductivity to produce the target oxidant concentration. In low-salinity water the available chloride falls and dose can become difficult to achieve, which is why electrolytic systems define salinity operating limits and some incorporate salt dosing arrangements.

A TRO analyzer monitors oxidant concentration during uptake to confirm effective dosing and during discharge to confirm the residual is within the maximum allowable discharge concentration. The control system interlocks treatment with flow and TRO signals, alarming or stopping the operation if parameters drift outside the approved range.

The generated oxidant continues to act during the voyage holding time, contributing to the overall organism inactivation that allows the system to reach the D-2 standard of fewer than 10 viable organisms per cubic metre for the larger size class.

Neutralization on Discharge

Because treated water leaves the tanks carrying residual oxidant, deballasting includes a neutralization step using a reducing agent such as sodium thiosulfate, dosed in proportion to the measured TRO. This brings residual oxidant below the discharge limit so the overboard water is not harmful to the receiving environment.

Reliable neutralization depends on an accurate discharge TRO reading and a managed reagent supply. As with any TRO-based system, the analyzer reagents have a finite shelf life and the neutralizing chemical must be kept in adequate quantity for the planned deballast volumes.

Erma First systems, like other active-substance BWMS, were assessed through the IMO process for systems using active substances to confirm the treated and neutralized discharge meets environmental safety criteria for residual chemicals and disinfection by-products.

Type Approval, Service and Parts

Erma First systems hold IMO type approval under the BWMS Code (MEPC.300(72)) and have achieved USCG type approval, enabling use in US waters when the installed model and capacity are covered by the certificate. The installed unit must still pass commissioning testing under MEPC.325(75) to demonstrate D-2 compliance aboard the specific vessel.

Routine maintenance covers filter element inspection and replacement, electrolysis cell and electrode condition, rectifier and power supply checks, TRO analyzer calibration with fresh reagents, and neutralization dosing equipment. The electrode and the filter screen are the principal consumables determining long-term performance.

Sea Clean AS supports operators across BWTS brands with spare parts sourcing, TRO and neutralization reagent supply, and field service. Correctly specified filter screens, electrodes, seals and reagents preserve performance and the validity of the type approval.

Frequently asked questions

What is the difference between Erma First FIT and BLUEGUARD?

FIT is Erma First's earlier filtration-plus-electrolysis system, while BLUEGUARD is a newer side-stream electrochlorination design optimised for smaller footprint, lower power and simpler installation. Both use filtration on uptake and TRO-based disinfection with neutralization on discharge, and both reach the IMO D-2 standard.

Are Erma First systems approved for US waters?

Yes. Erma First systems have obtained USCG type approval in addition to IMO approval, so they can be used in US waters provided the specific model and capacity are covered by the certificate. The installed unit must also pass MEPC.325(75) commissioning testing.

How does an Erma First system handle fresh-water ballasting?

Because the disinfection stage relies on electrolysis of chloride, performance falls as salinity decreases. The systems define salinity operating limits, and some configurations use salt dosing to maintain dose in low-salinity water. Owners with fresh-water trading should confirm the certified salinity envelope.

What are the main consumable parts?

The filter screen element and the electrolysis electrodes are the principal consumables, alongside TRO analyzer reagents and neutralizing reagent such as sodium thiosulfate. Seals, gaskets and instrumentation are routine replacement items. Sea Clean AS can supply correctly specified parts and reagents.

Sources

Sea Clean BWTS service desk · All Insights