BS EN 12255-12:2024
Wastewater treatment plants Part 12: Control and automation

Standard No.

BS EN 12255-12:2024

Release Date

2024

Published By

British Standards Institution (BSI)  GB  /  BSI

Latest

BS EN 12255-12:2024

Introduction

Key points of standard update and technological evolution

BS EN 12255-12:2024 is the UK's national implementation standard for EN 12255-12:2024, replacing the 2003 edition. The main technical changes include:

• Revision and expansion of all chapters
• Adapt to the latest technical level
• Update of normative references

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Analysis of core control requirements

Control hierarchy	Small treatment plant (＜250PT)	Medium treatment plant (10,000+PT)	Advanced control requirements
Basic control	Relay control	PLC system	Multivariable process control
Monitoring parameters	Flow/liquid level	DO/Ammonia/MLSS	Real-time Model Prediction
Typical Applications	Pump Station Control	Aeration System Optimization	Neural Network Control

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Instrument Lifecycle Management

Activated Sludge Process Control Case

Annex A of the standard details the five-stage management process:

1. Purpose Definition: Clarify the regulatory/process requirements for monitoring parameters (such as DO values)
2. Specification Selection: Consider the measurement range (0-10mg/L) and communication protocol (HART/Modbus) of the dissolved oxygen sensor
3. Installation specifications: avoid installation at pipe elbows to ensure maintenance access
4. Operation and maintenance strategy: calibration frequency ≥ 3 months/time, membrane module replacement cycle 12 months
5. Decommissioning assessment: equipment update or decommissioning is determined based on process changes

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Safety compliance requirements

Chapter 5 of the standard specifically emphasizes:

• Electrical safety must comply with IEC 60364 low voltage device specifications
• Equipment in explosion-proof areas should comply with ATEX 2014/34/EU Directive
• Network security must meet the requirements of the NIS Directive
• Lightning protection implements EN 62305-3 standard

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Implementation recommendations

Design phase

A complete P&ID diagram (piping instrument flow diagram) must be prepared, including:

• Installation locations of all online analyzers
• Control valve and actuator parameters
• SCADA system communication architecture

Debugging phase

Article 6.3 of the standard stipulates that the following must be included:

• Archive of instrument factory calibration certificates
• Signal loop end-to-end testing
• Control logic function verification
• Technical documentation retention period ≥ 10 years

BS EN 12255-12:2024 Referenced Document

• EN 16323:2014 Glossary of wastewater engineering terms
• EN 62305-3 Protection against lightning - Part 3: Physical damage to structures and life hazard
• IEC 60364 Amendment 1 - Low-voltage electrical installations - Part 8-82: Functional aspects - Prosumer's low-voltage electrical installations*， 2026-04-16 Update

BS EN 12255-12:2024 history

• 2024 BS EN 12255-12:2024 Wastewater treatment plants Part 12: Control and automation
• 2003 BS EN 12255-12:2003 Wastewater treatment plants - Control and automation

Standard and Specification