Mitsubishi unit bags sludge system order

Mitsubishi Heavy Industries Mechatronics Systems (MHI-MS), has picked up an order for wastewater treatment facilities using its two-phase, activated sludge system, for installation at sister company Mitsubishi Chemical Corporation’s Yokkaichi Plant in Mie prefecture.

MHI-MS said its system reduces excess sludge produced from the wastewater treatment process. by 80% and can double the wastewater treatment capacity according to MHMS. The system ordered by Mitsubishi Chemical has an wastewater treatment capacity of up to 9,000m³/day, compared with 7,500m³ from conventional systems claimed MHI-MS. Delivery of the system is scheduled for the first half of 2017.

The system’s biological treatment tank – where organics in wastewater are decomposed by microorganisms – differs from conventional design in that it is is divided into two parts.

In conventional activated sludge processing using a single aeration tank, bacteria that decompose and assimilate organics contained in wastewater share the tank with animalcules (protists and small metazoa) that feed on this bacteria.

In MHI-MS’s two-part activated sludge system, the speed of treatment in the first (carrier) tank containing the bacteria is considerably faster than that in the second (activated sludge) tank that contains the animalcules that feed on the bacteria. So the two-tank configuration maximizes biodegradation and treatment capacity for bacteria and animalcules the company explained. The scale of equipment can be optimized according to the two tanks’ treatment capacities, enabling savings in installation space according to MHI-MS.

The latest order is the second one to be installed at Mitsubishi Chemical. In 2012 MHI-MS installed a 3,600m³/d wastewater treatment system – replacing a 2,830m³/d conventional system – for installation at the company’s Kurosaki Plant in Fukuoka Prefecture.