Spiral conveyors keep sludge on the move in Egypt

Bahr El-Baqar plant

At what is now the world’s largest water treatment plant, engineering firm SPIRAC has supplied 2km (1.24 miles) of shaftless spiral conveyors for moving sludge to and from the sludge drying areas.

The $739M (£609M), 5.6 million m3/day Bahr El-Baqar plant – in Sinai, Egypt – will benefit from 32 inclined SPIROLIFT® (OK) conveyors for dried sludge, plus a further 32 inclined SPIROLINE® (U) conveyors for wet sludge.

Handling 490,000 ton/year of dry sludge (at drying level 24%) and 165,000 ton/year of dry sludge (at drying level 75%), the shaftless SPIRAC conveyors offer significantly less wear and much-reduced energy usage compared to shafted spirals.

SPIROLIFT® vertical conveyors feature an octagonal trough and liner with breaks included. These provide a key resistance point, which helps to prevent slippery materials from forming a rotating plug. Its innovative design encourages the material to move vertically with the spiral face.

Meanwhile, the SPIROLINE® horizontal conveyors from SPIRAC at Bahr El-Baqar feature a U-trough with a low RPM shaftless spiral riding on a special low friction long life trough liner.

Aimed at developing the Sinai Peninsula to maximize its natural resources, Bahr El-Baqar (a joint venture between Arab Contractors (Arabco) and Orascom Construction) will contribute to the reclamation of 400,000 feddans (approximately 415,000 acres) by recycling and using agricultural, industrial and sewage wastewater. This will be diverted from the western to the eastern bank under the Suez Canal. Upon treatment, all water will be dispensed in Sheikh Jaber’s Canal. Bahr El-Baqar will provide much-needed water to irrigate more than 168,000 hectares of plantations in Sinai.

In the first phase of sludge collection, sedimentary solids are transferred from sedimentation tanks to sludge thickening tanks.

For sludge thickening (the second phase), the sludge moves to stabilization and thickening to obtain a thicker sludge. This is followed by dewatering and a mechanical drying phase to have a higher dry rate of up to 24%. 32 inclined SPIROLINE (U conveyors) transport the sludge to the sludge drying beds at a total length of about one kilometre.

In the third and final phase (solar drying), dry sludge at a drying level of 75% is conveyed by 32 SPIROLIFT (OK) conveyors from the solar drying beds with a total of approximately one kilometre. These biosolids have multiple uses, including fertilizer for agricultural use and construction applications.