Abstract:
Trash in pit latrines is one of the largest challenges facing pit emptying technologies, including the
powered auger (the Excrevator), developed for improved emptying in lower- and lower-middle
income countries. This study focused on two trash removal methods in conjunction with pit
emptying by the Excrevator: (1) simultaneous removal of trash with sludge and (2) manual trash
removal prior to sludge removal. Simultaneous removal was tested by adding to the inlet of the
Excrevator system two cutting heads designed to reduce the size of trash particles before entering
the pipe and auger. Laboratory testing indicated that the auger will not provide the rotational speeds
necessary for proper maceration of fibrous materials such as clothing, indicating that a separate
maceration unit with higher rotational methods may be more appropriate. Four manual trash
removal mechanisms were designed to improve on existing manual trash ‘fishing’ tools such as iron
rods with fixed hooks. Two of these tools (the ‘claw’ and the ‘hook’) showed promising laboratory
results and were subsequently field tested in Mzuzu, Malawi. Both tools proved more efficient than
the current tools used in the field and have potential for use in Malawi.
