After the IMO Ballast Water Management Convention entered into force, ballast water treatment systems became standard equipment on newbuild vessels. However, the mainstream technologies – UV and electro‑chlorination – each have their own advantages and disadvantages. Improper selection or inadequate installation and commissioning can affect the reliable operation of the system. Based on extensive experience from numerous vessel applications, Jiangsu Haizhongzhou Shipping Industry Co., Ltd. has developed a complete technical solution from selection evaluation to commissioning verification.
Selection is the first and decisive step. The UV system uses high‑dose medium‑pressure UV lamps to destroy microorganism DNA. The equipment is simple, produces no by‑products, and is safe to operate, but it is sensitive to water turbidity and is unsuitable for use in ports with high sediment content. The electro‑chlorination system generates active chlorine by electrolysing seawater to kill organisms. It is applicable in a wide range of waters, but the system is complex and requires management of neutralising agents and monitoring of residual chlorine concentration. Haizhongzhou recommends selections based on the vessel’s operating routes: for vessels trading mainly in coastal and clear waters, the UV system is preferred; for vessels on worldwide routes that may call at ports with turbid waters, the electro‑chlorination system or a combination of both is recommended.
During the installation stage, the core issues are piping layout and space management. The treatment unit is typically installed in series on the discharge line of the ballast pump, requiring full‑flow treatment. Haizhongzhou pays special attention to reserving adequate maintenance space: UV lamps require periodic replacement, with lamp lengths typically between one metre and 1.6 metres – the extraction direction must be free of obstructions; the electrodes of electro‑chlorination systems require periodic cleaning, and the electrode chamber should be positioned for easy access. Pipe routing should avoid sharp bends and local diameter reductions to prevent excessive pressure loss. Haizhongzhou’s installation standard requires a straight pipe length on both sides of the treatment unit of not less than five times the pipe diameter to ensure uniform water flow.
Commissioning is divided into two steps: functional testing and bio‑efficacy verification. Functional testing is performed during mooring trials, verifying the system’s treatment capacity under full flow, pressure drop data, and alarm and protection functions. Haizhongzhou simulates various fault conditions – such as insufficient UV intensity, abnormal electrode current, low neutralising agent level – to confirm that the system correctly alarms and automatically switches to bypass mode or stops discharge. Bio‑efficacy verification requires a qualified third‑party testing agency to perform on‑board testing. Sampling is carried out during ballasting and deballasting operations, and the number of viable organisms in the treated water is measured. Haizhongzhou has participated in verification tests on dozens of vessels and has accumulated extensive experience in sampling port location selection and sampling procedure optimisation.
The successful application of ballast water management systems enables vessels built by Haizhongzhou to call at any port in the world without restriction, while fulfilling the corporate responsibility of protecting the marine ecosystem.
