Beneath a sprawling array of solar panels lies a story of sustainability at Siu Ho Wan Treatment Works. This facility plays a vital role in Hong Kong’s environmental efforts. It manages wastewater from Chek Lap Kok Airport, Tung Chung, Discovery Bay, and Disneyland.
Siu Ho Wan Treatment Works began as a preliminary sewage treatment works in 1998. It was upgraded in 2004 to a Chemically Enhanced Primary Treatment Works. This upgrade significantly improved its treatment capabilities. The plant can treat 180,000 cubic meters of sewage per day. Currently, it processes about 60,000 cubic meters daily.
A key feature of the Siu Ho Wan Treatment Works is its commitment to renewable energy. The Solar Farm, commissioned in 2016, is a testament to this commitment. It is the largest photovoltaic system among Hong Kong government facilities. The farm boasts around 5,000 PV panels. These panels generate approximately 1.2 million kilowatt-hours of electricity each year.
The Solar Farm is divided into three main areas: A, B, and C. Area B is the largest. It contains about 2,700 PV panels covering 7,200 square meters. This area alone produces 694 kilowatts. That is about 58% of the Solar Farm’s total output. Areas A and C have 700 and 900 PV panels respectively.
The PV panels face south. They are inclined at a 22-degree angle. Concrete bases support them instead of metal frameworks. This design choice protects the panels from strong winds. The concrete supports are positioned on the ground using their weight. This makes future relocation easier and reduces material waste. An automatic online inspection system identifies malfunctioning PV panels. This simplifies operation and maintenance.
The electricity generated by the Solar Farm is impressive. It equals the annual electricity consumption of about 360 households. This reduces carbon dioxide emissions by 840 tonnes per year.
Siu Ho Wan Treatment Works employs a rigorous treatment process. Sewage undergoes preliminary treatment to remove large solids and grit. Fine screens remove solids larger than 6 millimeters. Grit chambers remove sand larger than 0.25 millimeters. After this, the sewage moves to sedimentation tanks.
In the sedimentation tanks, chemicals like ferric chloride and polymer are added. These chemicals help form flocs. The flocs settle as sludge. Chain and flight sludge collectors remove the sludge. Scum collectors skim off lighter foam and floatable solids. The collected sludge and scum are then dewatered.
The treatment process removes 75% of suspended solids and 60% of Biochemical Oxygen Demand. To further protect the environment, UV disinfection facilities were installed in 2006. The treated effluent is disinfected before being released into the sea. This helps protect the habitat of the Chinese White Dolphin.
An odour management system with biotrickling filters mitigates foul odours. These filters remove 99% or more of hydrogen sulfide gas. Hydrogen sulfide is the main source of odours in sewage treatment.
Consider Siu Ho Wan Treatment Works as a model. It provides essential services. It integrates renewable energy and protects the environment. It embodies Hong Kong’s commitment to sustainable development. A visit here is a lesson in environmental stewardship.