Challenge

Spain is a very dry country, receiving less than 61cm of rain even during years of normal weather. Add to an already dry climate drought conditions for two years, and you have a recipe for disaster.

The drought of 2004-2005 was just such a disaster, causing disputes over water rights and limitations, bringing up concerns about sporadic rationing, and even spurring conversations of transporting water to dry coastal regions via coastal shipping. Such severe conditions are turning community leaders to wastewater treatment plants as an option for recycling water for irrigational purposes.

Solution

By adding a tertiary treatment step to existing plants, a highly refined effluent can be produced for sale.The Hydro-Clear® pulsed-bed sand filtration system features a unique underdrain system and a shallow bed of mono-media, fine-grained sand, a design which permits the filter media to be “pulsed” periodically as solids build up. This means filter runs are extended, and the filter is automatically kept on-line, despite varying loads and changing water characteristics.

Results

Hydro-Clear® pulsed bed sand filtration systems from Siemens Water Technologies were added to several wastewater treatment plants in Spain, and higher levels of filtration were achieved, making the effluent suitable for many water reuse applications including irrigation of agricultural land, golf courses, road medians, and parks. In addition, this reuse of water generates revenue and allows citizens to reduce their environmental impact on the community.

As many Spanish communities have discovered, reclaimed wastewater is a valuable supplement to unpredictable natural resources. By treating wastewater to reuse levels, these communities can supply high volumes of high quality irrigation water to some of their larger customers, who are willing to pay for a steady, dependable resource of refined wastewater.