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Water reuse technology projects in Macau

Provision of the 1st Greywater Recycling System and Sand filter backwash water recovering technology

Similar to the areas in lack of freshwater, Macau also faces the same challenge. Recycling of wastewater becomes an irrevocable trend to cope with decreasing of available freshwater.

With more than 10 years experience in wastewater treatment, Dunwell Engineering Co., Ltd. is now working with Melco PBL Entertainment and Macao Water Supply Co., Ltd. to introduce the wastewater recycling systems to Macau.

The 1st Macau Greywater Recycling System

Dunwell is commissioned by the first six-stars hotel-casino – Crown Macau to design and installation of the first Greywater Recycling System at Taipa Island, Macau. The Greywater Recycling System will recycle the greywater comprising with the hand washing and bathing wastewater. The recycled water will be used as toilet flushing and landscaping water so as to save the freshwater.

Although traditional wastewater treatment incorporation with advanced polishing technology could change wastewater to portable water, it requires a lot of space and the quality of its effluent would also be easily affected by the external factor such as changes of feed wastewater quality. Besides, initial investment is high. Dunwell recently developed a new technology called "Membrane Bio-reactor". It could not only effectively recycle the wastewater, but it also saves a lot of space. Because of this reason, Crown Macau adopts this technology for recycling the wastewater collected from the bathtub and hand washing basin. The recycled wastewater would be used as toilet flushing and landscaping water. About 65,700m3 per year of recycled water would be produced. Apart from saving a lot of space, Dunwell’s MBR system also provides an effective and reliable solution for treating different wastewater such as industrial wastewater, municipal sewage.

Advantages of Dunwell’s MBR System :
1. Advance technology, recycled water satisfies the reuse standard.
2. Save money by adoption of recycled water
3. Compact and easily to retrofit the existing wastewater treatment system.

Sand Filter Backwash Water Recovering System

In order to maintain the efficiency and effectiveness of the sand filter, water treatment works requires to backwash the sand filter so as to remove the trapped solids from the sand filter. Although Macau is scarce in freshwater, its water treatment works still requires about 2,000m3 per day of freshwater for backwashing those their sand filters. As the water tariff is $4.39/m3 in Macau, the direct economical lost is about 3 million per year. Because of this reason, Dunwell cooperates with Macao Water Supply Co., Ltd. to investigate the solution for recovering backwashing wastewater.

General filtration is difficult to recover the water from the backwashing wastewater consisting of high suspended solids. Frequent blockage and cleansing causes a lot of problems.

Dunwell’s VSEP vibrating membrane system could effectively recover the water from the high solids backwashing wastewater and its compact design is especially suitable for retrofitting the existing water treatment facility. The treated effluent from the VSEP system could be directly reused and save the extra expenses on further treatment. Besides, VSEP is also applied in the seawater desalination and other water treatment application.