A couple of years ago the Zero Discharge toilet split into two types; the ZD1 and the ZD2.
The ZD1 is for large facilities where there are likely to be a number of cubicles. Usually, an architect designs the building. NatSol has supplied ZD1s for public parks such as Richmond Park in London and the Lake District National Park.
ZD2s are for single or perhaps double cubicles in remote locations. The two shown above are on a sculpture park in Dorset. The client arranged the building design, manufacture and supply.
ZD2s are emptied by removing the pedestal, ventilation is likely to be passive. ZD1s have a row of emptying hatches to the rear of the building and ventilation is likely to be fan driven. A vacuum sludge tanker is required to empty both types. For more information go to: Zero Discharge.