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Our New Technologies : Hitachi Compact MBR (Membrane Bioreactor)

Introduction

"Hitachi Compact MBR (Membrane Bioreactor)" is a compact- packaged MBR wastewater treatment system and adopts membrane filtration process, which requires less space and yet provides higher treatment performance compared with the conventional treatment systems.

By combination of activated sludge treatment with immersed flat membrane modules, this new system can maintain the activated sludge concentration at a high-level in the reaction tank without use of a sedimentation tank for separation of liquids mixed with the activated sludge.
As a result, yield of the treated water is at a higher quality than ever before, as well as space saving and reduced operation costs are realized. Since sludge control in a sedimentation tank is eliminated, this treatment system has a feature of lower maintenance.

Treated water can be used for toilet flushing, irrigation, landscaping, concrete mixing and curing, for cooling water and for industrial water.

Hitachi Compact MBR" was jointly developed by Hitachi Plant Technologies and the Japan Sewage Works Agency (Governmental Organization).

In addition, we can provide RO (Reverse Osmosis) system. Therefore, we provide higher quality treated water with "Hitachi Compact MBR + RO System" for meeting customer's needs.

MBR Plant Image & Membrane Module

MBR Plant Image

Membrane Module

Flow Diagram

Hitachi Compact MBR" employs 2 or 3 membrane modules in a vertical formation, with each module containing multiple membrane sheets. Wastewater is effectively treated by simply passing through the flat sheet membranes.
The sewage is separated through suction and filtration, so that the filtrated water directly becomes treated water. Air is supplied from the air diffuser installed on the bottom of the aeration tank to prevent sludge from adhering to the membrane surface. Thus, the system can perform stable treatment without getting clogged.

Flow Diagram

Benefits to Customers

Low costs: standardized MBR
Short delivery period : 2 - 3 months (*depending on plant location/contract)
Variety of configuration: MBR only / MBR + RO / RO only
Treated water can be used for many purposes
Variety of capacity : From 50 m³/d
Compact and mobile type feature
Space-saving : compact and reduced footprint because of its short retention time and accumulated structure in a vertical formation.
High-quality treated water: as membrane's pore size is 0.1µm, the pathogens, coliforms and helminth egg can be removed. Treated water can be recycled for landscape and irrigation, etc.
Simple operation and low maintenance : simple flat membrane structure prevents fibrous screenings from being twined in raw water.
Less chemical / membrane element recyclable / remote control.
Less energy consumption : membrane module is set up vertically in multi-stages (maximum 3 stages); blower energy requirements are lowered to clean membrane surfaces.
Low operation cost: generated excess sludge is less, therefore disposal cost can be reduced.
High reliability: less clogging /smooth surface membrane

Membrane Unit Capacity

We can provide various membrane unit from 50 m³/d treatment capacity. Our standardized Type is 250 m³/d, 500m³/d, and 750m³/d (Please refer to the following table). They are applicable to larger treatment plants by multiplying standardized MBR units. 50m³/d and 100m³/d units are also available.

Capacity	Population (for reference)		Electricity
(m³/d)	Workforce Accomodation	Residence	Capacity(kVA)	Consumption(kWh/d)
250	1,200	1,000	15	190
500	2,400	2,000	27	340
750	3,600	3,000	36	500

(Remarks) Above energy consumption figures vary depending on actual operating conditions.

Applications

"Hitachi Compact MBR" can be utilized for many applications as follows;

Construction Workforce Accomodation
Small Communites
New Residential Areas
Resort Hotels / Areas
Factory Areas
Schools
Public Water Treatment Facilities (New Plants/ Plant Renovation)

Features

Membrane Specification	Type	Submerged flat sheet membrane → strong membrane surfaces which prevent filtration trouble
	Material	PVDF → smooth surface prevents clogging
	Pore Size	0.1µm → uniform distribution of pore diameter , high particle blocking performance, high water quality
	Membrane Area	1m²/ element
Flux	0.8 m³/m²/d → higher flux rate : higher treatment capacity
Number of Stage	Maximum 3 stages → energy & space saving
Biological Treatment	Retention Time	Over 3 hours → retention time is 1/4 compared with OD (Oxidation Ditch) process
Biological Treatment	MLSS	8,000 - 15,000mg/L
Sludge	Generated sludge volume is 2/3 compared with OD process
Sludge Treatment	Direct sludge dewatering is possible.
Space	Space is 1/3 less than OD process

Water Quality

The following water quality can be achieved by Hitachi Compact MBR. compared with conventional OD system.

Item		Raw Water	Treated Water
Item		Raw Water	Our Compact MBR	Conventional OD System
BOD	(mg/L)	193	1.0	20
T-N	(mg/L)	38	5.7	5.7
T-P	(mg/L)	7.8	0.3	0.5
SS	(mg/L)	250	<0.4	20
Coliform	(CFU/mL)	3.7×10⁵	Not detected	<3000
Escherichia Coli phage (Virus)	(PFU/100mL)	3.6×10⁵	1	2.7×10²