Ventilated Improved Pit (VIP) Latrine
Ventilated improved pit latrines, commonly known as VIP latrines, are an improvement to overcome the disadvantages of the simple pit latrines. The main problems associated with traditional simple pit latrines, i.e. fly and mosquito nuisance and unpleasant odors are effectively minimized by the action of a vent pipe, fly screen and a squatting cover in the VIP latrines. The whole system is properly engineered as an effective sanitation option for both rural and urban areas by designing the pit either as a single pit or an alternate twin-pit system. The single-pit can be emptied mechanically. In case of a permanent superstructure, an alternating twin-pit system permitting safe manual removal of the digested solid may be installed.
Ventilated Improved pit latrines receive excreta in the same fashion as those of the simple pit latrines, by direct deposition through a squat hole or a pedestal seat. The liquid part infiltrates into the surrounding soil and the faecal solid are digested anaerobically, gradually accumulating and eventually requiring emptying the pit for further use.
Elements of VIP latrines
The basic elements of ventilated improved pit latrines are:
- The pit, which can be either a single pit or a alternating twin-pit; in either case, the pit should be lined with open joined brick work or prefabricated concrete rings; the lining prevent soil collapse during emptying operations or during heavy rains ,and the open joints allows liquid to infiltrate into the soil;
- A cover slab, usually of reinforced concrete, which covers the pit and has two holes-the squat hole and the other for the vent pipe;
- A superstructure for privacy and protection from rain and sun, which can be built according to the choice of the users;
- The vent pipe and the flyscreen which keep the latrine free from flies, mosquitoes, and unpleasant odors.
Advantages of Ventilated Improved Pit Latrine
The major advantages of VIP latrine technology are as follows:
- Controls odor and insects;
- Minimum health risk;
- Low cost;
- Easy construction and maintenance
- Minimum water requirement;
- Twin-pit VIP latrine system offers a long- term solution.
Disadvantages of VIP Latrine
The major disadvantages of a ventilated improved pit latrine or VIP latrine option may be as follows;
- Potential for groundwater pollution;
- Lack of space for relocating the pit in densely populated areas;
- Difficulty of construction in rocky and high water table areas.