30 The priest is to sacrifice one for a sin offering and the other for a burnt offering. In this way he will make atonement for her before the LORD for the uncleanness of her discharge.

Read Leviticus 15:30 Using Other Translations

And the priest shall offer the one for a sin offering, and the other for a burnt offering; and the priest shall make an atonement for her before the LORD for the issue of her uncleanness.
And the priest shall use one for a sin offering and the other for a burnt offering. And the priest shall make atonement for her before the LORD for her unclean discharge.
The priest will offer one for a sin offering and the other for a burnt offering. Through this process, the priest will purify her before the LORD for the ceremonial impurity caused by her bleeding.