> ## Documentation Index
> Fetch the complete documentation index at: https://docs.appliedaifoundation.org/llms.txt
> Use this file to discover all available pages before exploring further.

# What is a Ballast Water Treatment System

> Primer on ballast water operations, why UV treatment is used, and the role of the 16-lamp array.

## Why ships carry ballast water

When a cargo vessel offloads its freight, it becomes too light to sail safely. Ships compensate by pumping seawater into dedicated ballast tanks to maintain stability, trim, and propeller immersion. This water — taken on at the origin port — contains microorganisms, bacteria, algae, and larvae native to that location.

When the ship arrives at the destination port and pumps the ballast water out, those organisms are released into a foreign marine environment. Without natural predators or competition, invasive species can dominate local ecosystems, causing irreversible ecological and economic damage.

## The treatment cycle

A BWTS treats water **twice**:

| Operation   | When                                    | Purpose                                    |
| ----------- | --------------------------------------- | ------------------------------------------ |
| `BALLAST`   | Water enters the tanks at origin port   | Kill organisms before they enter the ship  |
| `DEBALLAST` | Water is discharged at destination port | Ensure no surviving organisms are released |

Both operation types appear as `operation_type` values in the telemetry data. The system must be actively treating (lamps on, flow within limits) during both operations to be compliant.

## UV treatment method

This system uses **ultraviolet light** to disinfect ballast water. UV-C radiation at the correct intensity disrupts the DNA of microorganisms, rendering them unable to reproduce — even if they survive passage through the UV reactor.

The critical metric is **UV intensity**, measured in W/m² at the reactor sensor. The higher the intensity, the more effective the treatment:

* Below 252 W/m² → non-compliant with IMO D-2
* 252–530 W/m² → IMO D-2 compliant, not USCG compliant
* Above 530 W/m² → compliant with both IMO D-2 and USCG standards

## The 16-lamp diamond array

This installation uses **16 UV lamps** arranged in a diamond pattern across the reactor cross-section. The arrangement ensures full coverage of water flow with no untreated channels. Having 16 lamps provides two key advantages:

1. **Redundancy** — The system remains operational even if several lamps fail or degrade, as long as aggregate intensity stays above compliance thresholds.
2. **Progressive replacement** — Lamps can be replaced individually during port calls without taking the entire system offline.

The dashboard's Overview tab displays the 16 lamps in their physical diamond layout, colour-coded by efficiency.

## System components referenced in telemetry

| Prefix     | Component                   | Monitors                                     |
| ---------- | --------------------------- | -------------------------------------------- |
| `UVR_`     | UV Reactor                  | Intensity, power output, water temperature   |
| `LDC_`     | Lamp Drive Controller       | Air temperature, fan speed, fan status       |
| `FLT_`     | Filter System               | Differential pressure, backflush cycles      |
| `SYS_`     | Flow & Pressure instruments | Flow rate, pressure, valve position, volumes |
| `PLC_`     | PLC Controller              | CPU usage, RAM usage, CPU temperature        |
| `LAMP_XX_` | Individual Lamp (01–16)     | Status, efficiency, runtime, power           |

## Where operations happen

The `location` field in telemetry records the port name where each operation takes place. Ballasting and deballasting always occur during port calls — treatment is not active at sea.