本文介绍了巴西巴西利亚水处理厂为确定直接过滤的最佳条件而进行的中试工厂研究的结果。与明矾相比，三氯化铁的使用具有优势（过滤时间更长，出水浊度更低）。使用阳离子聚电解质来减少金属混凝剂的用量在经济上并不可行。直接过滤前的预絮凝被认为是不必要的，可能对性能有害。对于粗滤层，需要较高的反洗率，但反洗水总量低于正常值。包括8个参考文献、表格、图表。

This article presents results of a pilot plant study conducted to define optimum conditions for direct filtration at the Brasilia, Brazil, water treatment plant. The use of ferric chloride was found to offer advantages (longer filter runs and lower effluent turbidities) over the use of alum. The use of cationic polyelectrolytes to reduce the metal coagulant dosage was not found to be economically feasible. Preflocculation before direct filtration was determined to be unnecessary and possibly detrimental to performance. With a course filter bed, high backwash rates were required but with lower than normal total volumes of backwash water. Includes 8 references, tables, figures.