Characteristic image

Unique selling points

  • Compact solution for wastewater treatment and reclamation compared to conventional biological sludge treatment.
  • Regenerated water with high quality which can be reused for irrigation or other non-potable uses.

Description of the technology

Membrane bioreactor (MBR) is the combination of a membrane process like microfiltration or ultrafiltration with a biological wastewater treatment one, the activated sludge process. It is now widely used for municipal and industrial wastewater treatments. Two MBR configurations exist: internal/submerged, where the membranes are immersed an integrated into the biological reactor; and external/sidestream, where membranes are a separate unit process requiring an intermediate pumping step.

MBR are frequently used to reduce treatment footprint while obtaining high water quality that can be reused.

In the NextGen project, the MBR treatment will be applied for sewer water mining, treating water directly extracted from sewer and producing water to be reused for irrigation in an urban green zone. The MBR has been tested up to industrial scale. In the Nextgen project, the capacity of the MBR is around 25m3/d.

Flow scheme of the technology

 

Figure 1. Simplified P&ID of the NextGen pilot plant where MBR system is applied.

Pictures

Figure 2. Images of the MBR used in NextGen project.
Figure 2. Images of the MBR used in NextGen project.

Synergetic effects and motivation for the implementation of the technology

  • Production of reclaimed water from sewer in the point of use

MBR with desired sizes can be installed in decentralized systems to treat sewer extracted from the collector. Reclaimed water with high quality can be produced in the point of use, minimizing the costs of distribution.

Technology requirements and operating conditions

The following table summarize the most appropriated values of several parameters to take into account for the design and operation of an MBR.

Table 1. Required specifications for an MBR.

Parameter

Units

Min

Max

Reference

Organic Loading Rate (OLR)

Kg/m3/d

0.1

13

Depending on the wastewater type (urban or industrial).

Holler and Trösch, 2001

Boonyungyuen et al., 2014

Sludge concentration (Volatile Suspended solids)

g/L

4

12

Delgado, et al., 2011

Mixed liquor suspended solids (MLSS) or Total Suspended Solids

g/L

8

12

Delgado, et al., 2011

Solid retention time (SRT)

d

10

20

Delgado, et al., 2011

Specific aeration demand SADm

Nm3/h m2

0.30

0.57

Delgado, et al., 2011

Membrane porous size

nm

10

400

Delgado, et al., 2011

Gap sizes for the screens used during the pre-treatment

mm

0.5

3

Schier et al. 2009

Operation flux rates

LMH

14

48

Delgado et al., 2011

Yang et al., 2009

Key performance indicators

Table 2. KPIs for the MBR in the Athens case study.

Parameter

Units

Min

Max

Reference

Legislation Limits

COD in the MBR effluent

mg O2/L

13

32

NextGen, D1.2

-

BOD in the MBR effluent

mg O2/L

1

2.5

NextGen, D1.2

10 ppm for 80% of samples

TSS in the MBR effluent

mg/L

Detection Limit

Detection Limit (2)

NextGen, D1.2

2 ppm for 80% of samples

Turbidity in the MBR effluent

NTU

0.1

2.0

NextGen, D1.2

 

N-NH4+ in the MBR effluent

mg/L

60

85

NextGen, D1.2

 

Total P in the MBR effluent

ppm

5.0

7.0

NextGen, D1.2

 

Energy consumption

KW

15

17

NextGen, D1.2

 

Sludge generated

L

700

1000

NextGen, D1.2

 

 

Links to related topics and similar reference projects

 

MBR treatment

Reference

NextGen

Case study “Athens” (NextGen)

 


Case Study applying the technology

Publications

  • Schier, W. Frechen, F.B., Fischer, St., Efficiency of mechanical pre-treatment on European MBR plants, 2009
  • Yang, Q., Shang, H. T. and Wang, J. L., Treatment of municipal wastewater by membrane bioreactor: a pilot study, 2009
  • Holler, S. and Trösch, W., Treatment of urban wastewater in a membrane bioreactor at high organic loading rates, 2001
  • Delgado, S. Villaroel, R., González, E. and Morales, M., Performance Under Substrate-Limited Conditions, 2011
  • Boonyungyuen, W., Wonglertarak, W. Wichitsathian, B., Effect of Organic Loading Rate on the Performance of a Membrane Bioreactor (MBR) Treating Textile Wastewater, 2014