Manila Water Diego Silang Sewage Treatment Plant - Metro Manila, Philippines

Manila Water Diego Silang Sewage Treatment Plant is an operational wastewater treatment facility located in the Philippines, serving the densely populated metropolitan Manila region. As part of the Manila Water concession, it plays a key role in managing sewage from one of the world's most populous urban areas. The plant operates under the regulatory framework of the Philippines' Clean Water Act (Republic Act 9275), which mandates proper sewage treatment for urban agglomerations. While specific treatment process and capacity details are not disclosed, facilities of this scale typically employ secondary or advanced treatment to meet national effluent standards. The treated effluent is discharged into the Pasig River system, which flows through Manila and into Manila Bay, a vital water body supporting fisheries, transportation, and biodiversity. The plant's operation helps reduce pollution loads in this ecologically and economically important watershed.

The plant discharges into the Pasig River, which flows through Metro Manila and empties into Manila Bay. Manila Bay is a semi-enclosed estuary that supports diverse aquatic life, including mangroves and fisheries, and is an important migratory corridor for birds. The bay faces significant pollution pressures from urban runoff and untreated sewage, making the plant's treatment role critical for local water quality and downstream ecosystem health.