Beixiaohe Wastewater Treatment Plant Improvement Project, China

A two-year programme of work began in 2006 to improve Beijing’s Beixiaohe wastewater treatment plant ahead of the 2008 Olympics. It culminated in the provision of a new membrane bioreactor (MBR) wastewater reuse system – one of the largest of its kind in the world.

The project updated the plant’s previous mechanical / biological treatment, enabling capacity to be more than doubled – to up to 100,000m³ / day – to meet the increased water demand arising from the elaborate landscaping designs for the Games.

Beixiaohe supplied treated water for the Olympic Park and treated all the wastewater from the Olympic Village during the Games, but the enduring legacy of the work will be the continuing benefit of the upgraded treatment systems for Beijing’s population.

The improvement project cost was 270m yuan (€25m).

Background

China's capital and second-largest city Beijing has a population of more than 17m spread over a conurbation some 15,540km² in area. China's water use accounts for between a third and a quarter of the world’s average per capita and the city has long suffered from water shortage among other environmental problems.

Global concerns led Chinese government agencies to pledge that the Beijing Games would be as green as possible, with the Ministry of Water Resources promising that sustainable water management would be implemented on several levels.

Between 2000 and 2006, a total of 17 new WWTPs were built and more than 600km of new sewers constructed, significantly enhancing Beijing’s wastewater treatment capacity as part of the wider agenda for improving sustainable water policy. In 2006 this also saw an expansion and improvement programme begin at the existing Beixiaohe plant.

Located in the north of Beijing to the east side of the new Olympic Centre, the Beixiaohe WWTP – the city’s first modern sewage treatment works – was originally built in 1990 to service the inhabitants of the surrounding area. The improvement project was aimed at replacing the mechanical/biological approach to water treatment and increasing the original daily capacity of 40,000m³ by a further 60,000m³ / day.

Start-up of the plant’s new wastewater reuse system took place three months before the Games’ spectacular opening ceremony.

Plant design

Improving and enlarging the plant principally comprised the addition of an entirely new wastewater treatment line, specifically designed to achieve enhanced levels of water reclamation – and with a 60,000m³ / day design output.

The design hinges on a progressive process concept, with the MBR plant containing biological and membrane treatment steps to produce resource-protective recycled water for non-potable use. An additional reverse osmosis system treats 10,000m³ / day of the MBR’s output – used during the period of the Games for decorative fountains and the themed lake.

The MBR plant uses 4,864 Memcor Memjet hollow fibre membranes with a total membrane area of 180,000m², making the system one of the largest of its kind in the world. The approach achieves nutrient removal with simultaneous nitrification / denitrification – through aerated-anoxic technology, and provides a big boost to Beijing’s target of processing 90% of its wastewater, with 50% for recycle and reuse.

Besides the system’s efficacy, one of the key reasons for its selection was its significant reduction in footprint, requiring as it does 40% less space than other conventional technologies, which allowed it to fit within the existing plant’s site.

As part of the overall project, the plant was also fitted with new pumps, aeration blowers and a UV-light disinfection system, along with a series of new programmable logic controllers for an extensive on-site SCADA system.

Key players

The work was done for Beijing Drainage, with the main contractor being Beijing CNC Water Technology – a Siemens-led consortium including Wabag, which was responsible for the plant design. In addition to the MBR system, Siemens was responsible for providing process design, mechanical equipment, instrumentation, electrical and automation systems, supervising the installation, and giving operational and maintenance training.

The reverse osmosis membranes were supplied by Dow Water Solutions, with the pumps coming from Flygt.