The glomeruli filter fluid from your blood, extracting both waste products and substances your body needs — sodium, phosphorus and potassium.
肾小球过滤血液，从中摄取代谢废物和各种身体所需物质——钠、磷和钾（译者：离子？）
2
This is because new regulations, due to come into force in 2011, will require crematoriums to filter out toxic substances such as dioxins and mercury from waste gases.
这是因为将在2011年生效的新法规规定火葬场要过虑出废气中像二恶英，水银这样的有毒物质。
3
Here bulrushes filter and treat waste products added by waterfowl and algal production in the deep pool.