Features - Feasibility, optimisation and costs

Reuse of dairy wastewater treated by membrane bioreactor and nanofiltration: technical and economic feasibility

A study carried out by Andrade and co-authors assessed the viability of a two-stage membrane bioreactor−nanofiltration scheme (MBR−NF) for treating dairy wastewater. Of key concern was the quality of the treated water with respect to its potential reuse and the overall cost of the scheme.

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Feasibility, optimisation and costs | Pre-treatment and post-treatment | Water quality and treatability

Kunming Underground MBR: a Chinese case study

China features many of the largest municipal wastewater MBRs in the world. Apart from their capacity, some also are ambitious in their construction. The below-ground installation at Kunming City, commissioned in 2012, is one such example. At an ADF (average daily flow) capacity of 150,000 m3/d and a peak daily flow of 195,000 m3/d, it is a substantial plant.

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Membrane operation | Feasibility, optimisation and costs | Pre-treatment and post-treatment | Water quality and treatability

MBR OPEX − the theory of running costs

Operational costs in MBRs are marginally higher than those of conventional activated sludge (CAS). Firstly, permeating water through a membrane demands energy. In the case of the immersed technologies (iMBRs) this means that the overall specific aeration demand (SAD) is higher, since air is needed both for maintaining the process biology in the aeration tank and scouring the immersed membrane.

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Membrane operation | Process biology | Feasibility, optimisation and costs

Mechanical shear in membrane bioreactors

In membrane separation systems, it is probably shear which is the most significant parameter for driving the membrane process. Pressure is obviously important for forcing the water through the membrane but shear is arguably the property of the system which largely determines the rate of membrane fouling and so, ultimately, the flux.

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Feasibility, optimisation and costs | Pre-treatment and post-treatment | Water quality and treatability

Arla milk powder factory: membrane bioreactor plant for treating dairy wastewater

In 2012, the Arla milk powder factory in Sweden planned to expand operations. The increased production process generated larger wastewater volumes which the receiving municipal treatment plant was unable to process. Therefore, the dairy decided to build their own treatment plant on site, which needed to be installed within a short period of time and meet strict discharge requirements.

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Feasibility, optimisation and costs | Pre-treatment and post-treatment | Water quality and treatability

Foaming in MBRs: measurement and evaluation

Foaming of conventional activated sludge (CAS) is very common. It may happen during start-up due to the presence of surfactants, with insufficient biomass to degrade them during the early stages. However, this is normally a short-term issue. These foams (from surfactant foaming) are mostly white and can be countered with anti-foamants until there are sufficient biomass developed to degrade them.

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Process biology | Feasibility, optimisation and costs