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We focused on a practical treatment of animal liquid manure for land application using some materials in an aerated reactor. After solid-liquid separation of animal manure in a barn, liquid manure is moved to three to five tanks sequentially. At each tank a reactor is suspended and aerated with air pump. The reactor consists of pumice, granite, and soil pellet, not only promoting biological digestion of the manure but also providing some minerals in it. The soil pellet is sometimes alternated by the powdery soil, spread at the bottom of the tanks. The aerated reactor system is called "BMW", meaning bacteria, mineral, and wastewater. After qualified for three week to a month in the sequential tanks, the wastewater, low in organic materials and rich in minerals, is used for plant cultivation as an activated fertilizer.

In this study, we investigated the wastewater quality of the BMW plant installed at a large-scale swine farm as well as the modified BMW plant built at a small-scale swine farm. The BMW plant used the materials of soil, granite, and pumice in an aerated reactor. The modified BMW plant used charcoal, shell, and zeolite and therefore was renamed as the CSZ plant. A land application of the treated wastewater from the BMW plant was examined to yam potato production. In addition, at lab scale model plants we investigated the purification and mineral dissolution mechanism of the materials used in the BMW plant, the CSZ plant, and the Non-Material plant that used nothing in the aerated reactor.

Using the additional 5th tank and the scallop shell in the aerated reactors, the BMW plant kept a preferable condition of pH in the 4th and 5th tank and increased a conversion rate of NH4-N to NO3-N, remaining only 5% of inorganic nitrogen in the 5th tank. The treated wastewater from the BMW plant sprayed on a field in an amount of 3 t/10a made a significant difference in the yam potato harvest. The treated wastewater was considered as an activated liquid fertilizer. In the lab scale model plant experiment, the BMW plant decreased 40% of COD, the CSZ plant, 60%, and the Non-Material, only 20%. The CSZ plant achieved a great purification. The great purification for the CSZ plant was due to a high dissolution of Ca2+ from the shell, resulted in helping to neutralize with an acid of NO3-N and keeping an optimal condition of pH in the tanks.