Table:
text: Waste management in Hong Kong
Closed landfills
Closed landfills
Landfill Location_ Acres Opened Capacity Status_ Rehab_Period
Gin Drinkers Bay Kwai Tsing District 29 1960 3.5 million tonnes Closed 1999–2000
Ngau Tam Mei Yuen Long District 2 1973 0.15 million tonnes Closed 1999–2000
Shuen Wan Tai Po District 50 1973 15 million tonnes Closed 1996–1997
Ma Tso Lung North District 2 1976 0.2 million tonnes Closed 1999–2000
Ngau Chi Wan Wong Tai Sin District 8 1976 0.7 million tonnes Closed 1997–1998
Sai Tso Wan Kwun Tong District 9 1978 1.6 million tonnes Closed 1997–1998
Siu Lang Shui Tuen Mun District 12 1978 1.2 million tonnes Closed 1999–2000

text: Waste management in Hong Kong
Closed landfills
Closed landfills
Landfill Location_ Acres Opened Capacity Status_ Rehab_Period
Tseung Kwan O Stage I Sai Kung District 68 1978 15.2 million tonnes Closed 1997–1999
Ma Yau Tong West Kwun Tong 6 1979 6 million tonnes Closed 1997–1998
Ma Yau Tong Central Kwun Tong 11 1981 1.0 million tonnes Closed 1997–1998
Pillar Point Valley Tuen Mun District 38 1983 13 million tonnes Closed 2004–2006
Jordan Valley Kwun Tong 11 1986 1.5 million tonnes Closed 1997–1998
Tseung Kwan O Stage II-III Sai Kung District 42 1988 12.6 million tonnes Closed 1997–1999

Question: What is the total area of Sai Tso Wan opened before 1978 in Hong Kong Waste Management?