Secondary WWTP Upgrade Case Study

Suez operates over 2,200 wastewater treatment plants (WWTP) throughout the world providing sanitation services for over 65 million people. Many of these plants employ the activated sludge process to treat the wastewater resulting in high energy consumption, high operating costs and high greenhouse gas emissions. In addition, some of these WWTP have been constructed several years ago, and require upgrading to meet more stringent effluent limits (typically tighter nitrogen and phosphorous limits) or to meet higher COD load than originally designed. Therefore, Suez is always on the lookout for treatment solutions that can increase the capacity of existing, overloaded, WWTP while at the same time reduce energy consumption.

Solution

Suez has a strong focus on research and development and is very excited by the potential of the Membrane Aerated Biofilm Reactor (MABR) a groundbreaking technology for the aerobic biological treatment of wastewater as it can increase treatment capacity while at the same time reduce energy demand. In particular, the flexibility of deploying the MABR as a standalone system or directly into an existing activated sludge tank along with the high removal rates that can be achieved, make it an ideal technology for upgrading a WWTP.
In 2015 Suez and OxyMem began a collaboration to test the potential of MABR to upgrade an existing WWTP from secondary treatment only to tertiary treatment. The Montcada i Reixac located near Barcelona was selected as the test location. This plant is designed for secondary treatment only and is meeting all its current requirements. The MABR was seen as an ideal technology for any future potential upgrades.

The MABR has been demonstrated as an excellent solution for upgrading existing facilities to achieve a secondary treatment standard. In particular, the ability of the system to act as an upgrade to simultaneously remove high loads of COD and ammonia is unique, when compared to other fixed film technologies. It should be noted that the lower loading rate of 1.1 kg COD/m3/d, is at least twice the loading rate of most activated sludge plants. The ability of the OxyMem MABR to achieve a very high effluent quality demonstrates the potential of the MABR to function as a standalone system.