Portable water treatment apparatus

A portable waste treatment apparatus for treating hydro-excavation waste comprises an elongate frame formed from separable upper and lower frame sections 4, 6, wherein the upper frame section houses a mixing tank 8 for receiving and mixing waste slurry with flocculating or coagulating agents, a thickener tank 10 for receiving waste slurry from the mixing tank and a dewatering device 42 for dewatering sludge collected in the thickener tank, and the lower frame section houses a buffer tank 36 for receiving sludge from a sludge outlet of the thickener tank, a pump 40 for pumping sludge to the dewatering device and a water tank 38 for receiving water overflowing from the thickener tank. The upper and lower frame sections preferably have the dimensions of a standard shipping container. The thickener tank may have a circular outer wall and a coaxially arranged inner wall defining an annular water collection chamber. The thickener tank preferably comprises a central section (22, figure 6) located within the upper frame section and two side sections (24, 26) separable from the central section. The dewatering device is preferably a centrifugal separator.