Projects
Southern Water

Horsham new wastewater treatment works

Southern Water is investing £31 million to upgrade Horsham's new Wastewater Treatment Works (WwTW) in West Sussex. The scheme is designed to improve the quality of final effluent returning to the River Arun, increase treatment capacity to meet future population growth, and support compliance with tighter environmental standards.

Delivered by CMDP JV, a partnership between Costain and MWH Treatment, the Horsham New WwTW upgrade began in 2022 and was completed in 2025. The programme combines major process and mechanical improvements with significant reinforcement of the site’s electrical infrastructure, ensuring the facility can operate safely, efficiently, and reliably well into the future.

Sector	Water
End User	Southern Water
Contractor	CMPD JV, Costain & MWH Treatment
Location	Horsham, West Sussex
Scope of Work	1250kVA Wilson T2 Ecotrans® Distribution Transformer 500kVA Wilson T2 Ecotrans® Distribution Transformer

We supplied two CRGO Wilson T2 Ecotrans® Distribution Transformers with ratings of 1250kVA and 500kVA, designed for long-term resilience. Both are equipped with magnetic oil gauges, temperature indicators, and marshalling boxes for full integration with the site’s control and protection systems, enabling enhanced monitoring, fault response, and operational reliability. Each transformer is close-coupled to an RN2d ring main unit, providing a compact, robust switching solution that ensures redundancy and safe maintenance.

The new transformers are central to powering advanced treatment processes, helping return cleaner water to the River Arun while safeguarding long-term efficiency and resilience.