Abstract:
WASP 6.0 (EUTRO) was applied to estimate the carrying capacity of Pak Phanang River on organic waste loading. The achievement of water quality goal was set to maintaining a DO concentration of 4.0 mg/L according to the river class 3 of Thailand's surface water quality standard. The average annual organic waste loads was estimated from secondary data collected in 2002 to 2003, as 2,978 kg/day. The results showed that loading capacity of the river from Mai Siap weir to Kuan kreng swamp forest was 1,175 kg/day which can receive additional load about 7 times of the existing loads. Loading capacity of the river from Kuan Kreng swamp forest to Klong Chian Yai was 130 kg/day which requires 80 percents treatment of the existing loads. Loading capacity of the river from Klong Chian Yai to Uthokvibhajaprasid Gate was 874 kg/day which requires 60 percents treatment of the existing loads. Consequently, it was calculated that total loading capacity of Pak Phanang River was 2,179 kg/day.