May 2006

Order for six containerised MBR plants

ACWA Emirates LLC – the Middle East subsidiary of ACWA Services - has supplied six Containerised, Mobile, Sewage Treatment Plants for use at desert site camps during the construction of major gasification projects in Abu Dhabi (UAE).

Designed and built by ACWA Emirates for Consolidated Contractors Company (CCC), two of the plants are to be used for treating raw sewage at the Ruwais 3rd Natural Gas Liquification site and the others at an Onshore Gas Development project in Habshan.

The containerised processes and associated storage tanks (each with a capacity of 300m3/hour) are fully transportable and can be easily and speedily relocated at other sites once the projects are completed. Each process is remotely operated - requiring no more than weekly monitoring - and can be easily expanded to accommodate additional tanks or membrane units if required, to meet any future increase in flow.

Designed to handle sewage from an anticipated population of 7,500 site workers, the mobile treatment processes are based on Kubota Submerged Membrane Bioreactor (MBR) Technology and are capable of treating raw sewage up to a peak demand of 1,500m3/day. At the process design stage, ACWA anticipated a high peaking factor and derived a peak hourly flow rate for each plant of four times that of peak daily flow - or 166m3/hour.

Kubota low maintenance, flat plate submerged membrane systems were selected for use on these systems because of their ability to provide a final effluent which more than meets the stringent ADNAC Water Standards for irrigation and discharge to the sea or desert terrain.

The treatment process is designed to produce high quality effluent from a BOD loading of 60g/person/day, with a BOD concentration of 300mg/L and COD concentration of 600mg/L. Each plant has a peak flow capacity of 33m3/hour with the membrane tanks operating at an MLSS range of 12,000 to 18,000mg/L.

Treated effluent will be used as flush water for on-site ablution blocks and for spraying on desert roads to limit the amount of blown sand and improve compaction. Surplus effluent is to be sold on to local cement manufacturers for use in the production process.