Here’s how one plant lowered operating costs with a disinfection upgrade.

Municipalities today are required to address numerous challenges around water disinfection – including regulatory compliance, environmental impact, operational costs, as well as equipment aging and maintenance. The Wahiawa wastewater treatment plant in Leeward Oahu district, Hawaii, was looking for ways to lower operational cost and the environmental impact of the disinfection process. The 6.5 mgd (peak) wastewater treatment plant originally installed a TrojanUV4000 in 2001 to disinfect the effluent to Class R-1 (reuse) standards. Advancements in UV efficiency are especially important in Hawaii where power costs are very high ($0.28/kWh). 

As UV lamp technology evolves and reactor design advancements are made, opportunities for reducing the costs and environmental impact of wastewater disinfection emerge. Innovations in the lamp technology, along with UV reactor design, system controls and monitoring, and automated sleeve cleaning systems, have significantly improved overall UV system efficiency. The Wahiawa wastewater treatment plant initiated a plant upgrade project in 2011 that included installing a membrane bioreactor and a new TrojanUV3000Plus. The new UV system allowed the municipality to achieve its goal to lower power use, operational costs and environmental impact. 

With the TrojanUV3000Plus, UV lamps are mounted on modules installed in open channels. The lamps are enclosed in quartz sleeves, and positioned horizontally and parallel to water flow. A bank is made up of multiple modules placed in parallel. All ballast and lamp wiring runs inside the module frame.

The TrojanUV3000Plus installation upgrade included benefits such as the ActiClean automatic sleeve cleaning, variable lamp output from 60 to 100 percent and high-efficiency amalgam lamps. The combined impact of the advanced treatment upgrade was power savings of 74 percent and a parts cost reduction of 20 percent for the disinfection process. The operations staff has also enjoyed easier servicing, smaller footprint, simpler equipment access and quick troubleshooting.

About TrojanUV
For more than a quarter of a century, Trojan has led the development of water treatment solutions using environmentally friendly ultraviolet light. Today, the company has the largest installed base of UV systems in operation on the planet, and many of its innovations define the industry standards for safeguarding our water from the damaging effects of microbial and chemical contamination. For more information, visit

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