Abstract: There is provided waste treatment apparatus generally indicated as 10 and comprising a moulded plastic tank portion 11 forming an electrolysis chamber 13 and a holding chamber 14 separated by a bulkhead 15. The tanks are mutually closed at their tops by tank top 16 which closes over the bulkhead 15 to form substantially isolated spaces in the respective tanks. The electrolysis chamber 13 receives waste entrained in sea water from a macerating marine toilet (not shown) via a waste inlet 17 disposed at the upper portion of the electrolysis chamber 13. A displacement tube 20 picks up waste from the bottom of the electrolysis chamber 13 and discharges to the top of the holding chamber 14. A series of ruthenium/iridium oxide coated titanium electrode pairs 21 are disposed generally vertically to encourage vertical column circulation in the electrolysis chamber by virtue of the action of outgassed electrolysis products.