UV Disinfection- Hanovia

UV Wastewater Disinfection

Ultraviolet disinfection is very popular in wastewater disinfection, largely due to the fact that, unlike chlorine, it does not increase effluent toxicity. Pressure from Governments and environmentalists to eliminate unwanted chemicals from the ecosystem, whilst providing pathogen free water, is also driving interest in ultraviolet disinfection systems, leading to many wastewater plants being converted form chlorine to ultraviolet disinfection. Water re-use is also becoming important as pressure on water supplies increases due to population expansion and prevalence of drought conditions, with purified wastewater disinfected by ultraviolet disinfection systems increasingly being used for irrigation in accordance with European and other guidelines. Hanovia has developed products specifically for this market to meet the very demanding disinfection requirements. Our advanced products and solutions are making ultraviolet disinfection the preferred technology for wastewater disinfection.

Wastewater disinfection systems can be classified as open-channel and “in-pipe” closed vessel. Open channel designs usually include low intensity (low pressure) ultraviolet lamps housed in modules or racks that are placed in the flow channel where gravity fed water flows over the lamps. Sophisticated controls and carefully designed inlet conditions are required to ensure that the lamps will remain submerged and that flow is evenly distributed to ensure no short circuiting and loss of disinfection performance. Most of these systems require the lamps to be manually cleaned by an operator, involving the physical removal of the banks of lamps.
Hanovia’s novel “in-pipe” closed channel approach uses high intensity (medium pressure) lamps in a closed vessel installed in the effluent header pipe prior to the discharge. In-pipe systems do not have the same requirements for inlet design and our careful hydraulic design ensures that the flow is always evenly spread inside the chamber giving optimum disinfection performance. Using high intensity lamps enables us to treat wastewater effluent in a small space (up to 5% of an open channel system) and a reliable automatic cleaning system removes any deposits from the quartz lamp housings that may reduce the intensity level of ultraviolet transmitted into the water. The high ultraviolet output from these lamps also enables the use of up to 95% less lamps than an open-channel system to achieve the same disinfection performance, significantly enhancing reliability and reducing maintenance costs.

Further benefits include much lower headloss when compared to open channel designs and the effectiveness of medium pressure lamps in eliminating “photoreactivation”, or bacteria self-repair, a phenomenon observed with low pressure lamps in the presence of sunlight which can impact negatively on pathogen reduction and can affect the effluent limits.

Hanovia’s reliable ultraviolet monitoring system alerts operators if the ultraviolet intensity drops below the correct level due to lamp degradation, auxiliary cleaning, water quality changes etc. Our control system can bring on parallel chambers to accommodate varying flow rates and interface with SCADA systems for operational and monitoring functionality.

Wastewater re-use requires a higher degree of treatment and hence a higher ultraviolet dose. Hanovia “in-pipe” systems are ideal for these applications as they can provide high dose levels from a small footprint and much lower numbers of lamps than a typical open channel system.

Call 03 8795 7711 to discuss your wastewater UV disinfection requirements.