Municipal Wastewater Treatment is experiencing tremendous change with effluent discharge permits requiring higher levels of advanced treatment, including tertiary filtration. The Tertiary Filter, is an upflow, continuous backwash, granular media filter that efficiently removes suspended and colloidal solids while providing a continuous supply of filtered water. Our filters are available in various circular models for different flows and applications.
The dirty sand is continuously removed from the active sand bed through the action of the air-lift pump, which draws the contaminated sand from the bottom of the filter body. A mixture of sand, dirty particles and water is transported upwards through the air-lift pipe into the washing chamber at the top of the filter. The separation of impurities from the sand takes place in the exclusive washing system. This is accomplished through the action of a counter current stream of raw water, injected at the bottom of the washing chamber. The sand is returned by gravity to the top of the active sand bed after being routed downward through a labyrinth composed of several settling steps. The feed water is fed into the filter at the base of the active sand bed through the distribution ring. It then flows upwards through the downwards moving sand bed where the solids are intercepted. The clean filtrate exits the filter through the overflow weir. The continuous reject flow of reject washing water is discharged through a separate outlet.
- Unique continuous back-washing system which uses raw water rather than filtered water
- High efficiency and reliability in the removal of suspended solids, even colloidal particles
- Ease of maintenance thanks to the simple and reliable external sand air-lift system
- Ease of installation
- Possibility of gravity feed thanks to very low (operating) pressure drops
- Low capital and operating costs
All wetted parts are made of 304 stainless steel. 316 stainless steel or other special construction materials are available upon request.
Sectors of Application
- Surface water clarification
- Treatment of drinking water
- Primary filtration in municipal/industrial WWTP
- Tertiary treatment in municipal/industrial WWTP
- Pre-treatment for membrane ultra-filtration plants
- Pre-treatment for ozonisation treatment plants
- Final treatment upstream of active carbon systems
Laois Grouped Towns Sewerage Scheme