'''Motorized emptying and transport refers to a vehicle equipped with a motorized pump and a storage tank for emptying and transporting faecal sludge and urine. Humans are required to operate the pump and manoeuvre the hose, but sludge is not manually lifted or transported.'''
A truck is fitted with a pump which is connected to a hose that is lowered down into a tank (e.g., [[Septic Tank| Septic Tank]], S.9) or pit, and the sludge is pumped up into the holding tank on the vehicle. This type of design is often referred to as a vacuum truck. Alternative motorized vehicles or machines have been developed for densely populated areas with limited access. Designs such as the Vacutug, Dung Beetle, Molsta or Kedoteng carry a small sludge tank and a pump and can negotiate narrow pathways.
===Design Considerations===
====Vacutug====
The UN-HABITAT Vacutug Project was conceived in 1995 with the goal of developing ‘fully sustainable system for emptying pit latrines in unplanned, periurban peri-urban areas and refugee camps in the developing countries’. The Vacutug consists of a 500 litre steel vacuum tank connected to vacuum pump which is connected to a gasoline engine that has the capacity to remove sludge (or urine) at 1,700 litres a minute. On level ground, the vehicle is capable of around 5km/h. The waste sludge can be discharged under gravity or by slight pressurization from the pump. Recent results indicate that under certain circumstances (constant number of pits, transfer station, short transfer distance, etc.) the Vacutug can be sustainable and cover its operating and maintenance costs.
A manually operated version of the Vacutug is the [[Human-Powered Emptying and Transport#MAPET|MAPET]].
Depending on the Collection and Storage technology, the sludge can be so dense that it cannot be easily pumped. In these situations it is necessary to thin the solids with water so that they flow more easily, but this may be inefficient and costly. Garbage and sand make emptying much more difficult and clog the pipe or pump. Multiple truckloads may be required for large Septic Tanks.
Although large vacuum trucks cannot access areas with narrow or non-driveable drivable roads, they remain the norm for municipalities and sanitation authorities. These trucks can rarely make trips to remote areas (e.g., in the periphery of a city) since the income generated may not offset the cost of fuel and time. Therefore, the treatment site must be within reach from the serviced areas. [[Transfer Station - Underground Holding Tank | Transfer Stations ]] (C.7) and adequate treatment are also crucial for service providers using small-scale motorized equipment. Field experiences have shown that the existing designs for dense urban areas are limited in terms of their emptying effectiveness and travel speed, and their ability to negotiate slopes, poor roads and very narrow lanes. Moreover, demand and market constraints have prevented them from becoming commercially viable.
Under favourable circumstances, small vehicles like the Vacutug are able to recover the operating and maintenance costs. However, the capital costs are still too high to sustainably run a profitable business. Both the sanitation authority and private entrepreneurs may operate vacuum trucks, although the price and level of service may vary significantly. Private operators may charge less than public ones, but may only afford to do so if they do not discharge the sludge at a certified facility. Private and municipal service providers should work together to cover the whole faecal sludge
===References===
* Boesch, A. and Schertenleib, R. (1985). Pit Emptying on-Site Excreta Disposal Systems. Field Tests with Mechanized
Equipment in Gaborone (Botswana). International Reference Centre for Waste Disposal, Dübendorf, CH.
