TREMATODA
The trematoda is a class of flatworms that is known only for bad things because its parasitic behavior. In order for the trematoda to excrete waste they use two kidney-like structures known as nephridiums, which filters waste into a bladder. The waste leaves the bladder to be excreted from pores on the end of the animal via excretory pore.
Tapeworms (Cestoda)
Cestoda have very similar urinary systems to the Digenea. The Digenea's waste is known to contain a substantial portion of physical waste, the Cestoda also is known to have very diluted waste. This is a effect of the Cestoda's attempt to balance the water level within its body. Excess water often enters, and must be forced out through excretion of the proglottids due to its osmotic environment.
dIGENEA
Inside the Digenea, small tube-like structures (or tubules) end in flame cells, which propel waste into a posterior bladder. Through an excretory pore the bladder than excretes the waste. This excretory system does not focus on removing water, unlike the urinary systems of other Platyhelminthes. Rather, on the food it excretes a significant portion of physical waste.