求翻译：真空排污系统的最佳真空度为0.02MPa～0.03MPa、最佳用水量为1 L/次～2 L/次及最佳抽吸时间为1s～1.5s。真空排污系统的节水节能效果明显，用水量只有传统重力卫生系统的0.25%，能耗只有42%。是什么意思？

Best vacuum for vacuum sewage system for the 0.02MPa~0.03MPa, the best water to 1 l/l/~2 times and optimal suction time for 1s~1.5s. Vacuum sewage system of saving water energy conservation effect obvious, only traditional gravity water 0.25% of the health system, energy consumption is only 42%.