All the settled sludge and the rapidly filtered backwash water produced in the process of water purification are discharged into the sewage pool, and the sludge is then pumped by the sewage pump to the sludge processing plant where it is thickened, dehydrated, and compressed into sludge cakes. The cakes are then recycled. Since the process turns waste into useful materials, the water purification station represents a 100% zero-pollution and zero-discharge green industrial operation.
Before 2002, various companies were commissioned to regularly transport the sludge cakes to the Shanzhuku Landfill site in Neihu, for free use as landfill cover soil. In 2003 the Shanzhuku Landfill had sufficient cover, and the Taipei Water Department began looking for other legal and economical ways to deal with the cakes. Their use as raw materials in the making of bricks and cement not only saves expenses dealing with the cakes, but also significantly reduces the shipping costs involved for the cakes to be recycled.