| 摘要 |
<p>A fertilizer is composed of about 50 per cent moist sewage sludge, 15 per cent of chalk, 5 per cent of slaked lime, and 30 per cent of dust siftings, vegetable matter and food washes in approximately equal proportions. The materials are mixed in a crushing and mixing mill and dried. Mineral manures, e.g. sulphate of ammonia may be added to the mixture.</p> |
