A porous and permeable composite for treatment of contaminated fluids, said composite including a body of iron particles and 0.01-10% by weight of at least one functional ingredient distributed and locked in the pores and cavities of the iron body. Also, methods of making a permeable porous composite for water treatment. Also, use of a permeable porous composite for reducing the content of contaminants in a fluid, wherein said fluid is allowed to pass through the permeable composite.