Features - Water quality and treatability

NF testing set-up

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

Rotary drum screens

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

Membrane technologies with modes of movement: (a) rotating and vibrating disc filters (RDF and VDF), indicating torsional motion; (b) multiple shaft disc (MSD), overlapping; (c) vibrating membrane (e.g. hollow fibre, vibrating hollow fibre membranes (VHFM)) (Zsirai et al, 2016)

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

Grundfos BioBooster MBR plant treating dairy wastewater at the Arla factory, Vimmerby

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

a) bubbly flow; b) slug flow; c) annular flow

Improving MBR flux: Ultrafiltration with a twist

In autumn 2015, after two years of research and development, Pentair brought to market its new ‘Helix’ product. An enhancement to X-Flow tubular membrane technology, Helix features a helically-winding ridge on the inside of the membrane which is designed to tackle cake build-up and enhance flux. The technology has so far been tested on both industrial effluents and municipal wastewater.

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

Impact of different cleaning reagents

Effects of ferric and ferrous iron addition on membrane bioreactor effluent quality

Municipal wastewater usually contains between 4 and 12 mg/L total phosphorus (TP) concentrations in the range 4−12 mg/L. A conventional activated sludge process (CAS) can take this down to 2−4 mg/L, or 0.5−1 mg/L if an enhanced biological phosphorus removal (BPR) process is used. To achieve the levels required to suppress eutrophication, however, demands P levels of 0.01−0.3 mg/L

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Pre-treatment and post-treatment | Water quality and treatability