| 摘要 |
<p>A treatment bed, for treating water containing eg. phosphorous contaminants, comprises a permeable body of particulate material through which the contaminated water is passed, the material having a permeability which causes the water to reside in the bed long enough to reduce the contaminant concentration. Preferably the contaminants are removed by adsorption and/or precipitation. A proportion of the treatment material consists of metal oxides and a proportion of the oxides consists of iron oxide and calcium oxide. The weight of iron is at least 15% of the weight of all the oxides and the weight of calcium is at least 5%. Preferably at least 5% of the material is limestone, the limestone being composed of particles of such a size so as not to clog up the treatment material. The apparatus may comprise a septic tank (Fig 4) or a trench formed in an aquifer (Fig 6).</p> |
