Paper for ICV-3
Vetiver Used in Constructed Wetland for Swine Wastewater Treatment Presented by
Liao Xin Di Wu Yin Bao
Luo Shi Ming Wang Zhi San
South China Agricultural University
Outline 1 The pig farm wastewater pollution in China 2 The present technology of pig farm wastewater treatment in China 3 Way to improve the effluent quality by vetiver grass 4 The ability of decontamination by vetiver grass 5 Vetiver Constructed Wetland used in pig farm wastewater treatment 6 Prospectives
1 Wastewater Pollution from the Pig Farm The animal husbandry develops quickly in recent 20 years in China. Animal production in China has been changed from discrete operation to intensive one. The intensive swine industry has resulted in serious pollution that has aroused general concern of government and people.
Washing
wastewater
What is the pig farm wastewater? Organic (COD & BOD),N & P Even heavy metal, pathogen & others Mainly from nutrient digestion in animal N, P, Cu, Zn
Waste
2 Current Technology of Pig Farm Wastewater Treatment in China (1)Separation:solid separated from the liquid by screen and/or settling tank (2)Anaerobic treatment: acidification tank or methane tank (3)Aerobic treatment: oxidation pond, hydroponic system, fish pond , constructed wetland,
Grid Screen, Settling Tank °˝ Anaerobic Process (Acidification or methane Tank) °˝ Aerobic Treatment (Oxidation Pond Constructed Wetland Fish Pond)
3 Find plant to enhance the removal rate of N,P
The difficulty of the current technology lies on: although organic matter is easy to be removed, the N,P remained in the effluent is hard to be removed Try to find the plant to improve the effluent quality
Collecting plants
Plants were cultured in the pig farm wastewater to find suitable species
The plants were evaluated comprehensively for their: (1) Pollution resistance (2) Biomass accumulation (3) Root growth (4) Landscape beauty (5) Management cost
Vetiver
4 Measure the ability of decontamination
Vetiver could grow in pig farm wastewater with COD 825 mg/L, BOD 500 mg/L, NH3-N 130 mg/L & TP 23 mg/L, and cut down those index to 64%, 68%, 20% and 18% respectively by 4d HRT.
600
1000 800
Vetiver Umbrella Control
COD 600 mg /L 400 200 0
Vetiver Umbrella Control
BOD400 mg /L 200 0
0
2
4
6
8
150
Vetiver Umbrella Control
NH3 100 -N mg /L 50 0 0
2
4
6
8
0
HRT?d?
HRT?d?
2
4
6
8
30 25 TP 20 mg15 /L 10 5 0
HRT?d?
Vetiver Umbrell a Control
0
2
4
6
8
HRT?d?
5 Constructed wetland covered with Vetiver
Vetiver was tested in subflow constructed wetland for measuring its ability of decontamination in green house.Results showed in another paper.
Planting
Mature
Growing
Tested outdoor
After harvest
Harvesting
Regrowth
Constructed wetland covered with vetiver
Effects : reduce SS,COD,BOD, N,P, heavy metal
Effluent:high quality
Easy operation
Landscape: nice, however
Influent required pre-treatment
Low cost required for construction
Harvest required to be recycled
6 Prospective
Vetiver not only for water & soil conservation, also develop rapidly for wastewater purification The scientific research will be enhanced for vetiver’s further application. A great progress will be made in this field in South China Agricultural University.
Thank you!
