Vietnamese Nguyen Xuan Khoat has been using bio-slurry for 11 years in which period he learned how to optimize its use to his farm needs. Each day his 80 pigs produce about 120 kg of fresh dung. Nguyen collects the dung to produce compost and biogas. Forty kg is stored in a brick pit where it is mixed with straw and ash to turn into compost fertilizer for use in his coffee garden.
The remaining 80 kg is diluted as part of the cleaning process and fed into a bio-digester. Biogas is used for household cooking. After digestion the bio-slurry (digestate) first flows in a slurry pit also to be mixed with straw and ash. Through an overflow, 80% of the remaining liquid slurry flows into a second pit to irrigate the coffee and vegetable gardens via spraying system. The remainder 20% flows into a pond with fish for home consumption. The mixed bio-slurry from the first pit is dried and applied to the soil. Nguyen decided to invest in a bio-digester as he has been aware of high quality nutrients in bio-slurry and its advantage of a continuous supply to his crops. Each year, he now saves 30%, or 100 kg of NPK synthetic fertilizers purchase, while each month his family saves up to 12 kg of LPG for cooking.
Note: in order to avoid human health risks bio-slurry should not be applied on vegetables and fruits for fresh consumption.