SANITATION: Sanitation generally refers to the provision of facilitiesand services for the safe disposal of human urine and feces.•Sanitation is the hygienic means of promotinghealth through prevention of human contact withthe hazards of wastes.•Hazards can be either physical, microbiological, biologicalor chemical agents of disease. Sanitation can be divided into two basic types :1. On-site sanitation2. Off-site sanitation
On-site sanitation systems include those inwhich safe disposal of excreta takes place on or nearthe plot or site of the toilet. Onsite sanitation can be classified into twomain categories:1. ‘wet’ which require water for flushing; and2. ‘dry’ which do not require any water for flushing.
It is a simple wooden or concrete slab installed over a pit of 2 m or more in depth. Excreta fall directly into the pit through a drop hole or a seat. This type of latrine is a simple pit covered by a slab with a drop hole. A superstructure is necessary to provide privacy and protection.Advantages•Relatively cheap•Can be constructed by the user (particularly in rural areas)•Does not need water to function•Easy to maintain•Considerable nuisance because of flies, insects (mosquitoes if pit is wet)•Bad smell
A pour-flush latrine iscomposed of a pan with awater-seal installed in asuperstructure. The water-seal is connected to a pit bya pipe. Advantages •Relatively cheap •No smells, no flies and mosquitoes •Agreeable to use •Can be improved by a connection to a sewer network at the right moment •Low water consumption 2 – 3 liters of water for each flush Disadvantages •A source of water is needed •The use of solid cleansing material is not advisable (except paper) •Skilled labor (mason) is required •There are two kinds of VIP latrines: pour-flush latrines with one pit and pour-flush latrines with double or multiple pits
These are also called self-ventilatedimproved pit latrines. The principle is tocancel or to reduce harmful side-effectsThis vent-pipe is fitted at the end by amesh that stops flies from enteringAdvantages•Relatively cheap•Can be constructed by the user•Does not need water to function•Easy to maintain•No smell and no flies•It can take different sorts of cleansing materials (solid and liquid)Disadvantages•Darkness is indispensable within the superstructure to fight off flies•Only functions properly when conveniently oriented towards the wind•No surrounding obstacle (trees and buildings) should be higher than the vent pipe•There are two types of VIP latrines: one pit latrines and double or multiple pitlatrines.
Ecosan latrines are latrines that ensure the recovery of waste by separating urine and faeces in view of their reuse in the fertilization of soil for agricultural purposesAdvantages•Recovery of urine and waste products•No pollution of ground water•Very hygienic•Easy to maintain•Does not need water to functionDisadvantages•Containers for urine storage are needed•Water is not recommended for cleansing•Addition of ash is required after every use•Overhead pits require climbing stairs to access the facility•Skilled labor (mason) is required•Apart from these latrines described above, there are other facilities which alsohave advantages and disadvantages. They are: cat latrines, compostinglatrines, septic tank latrines, aqua privies, etc.
•A septic tank is a water tight tank•An aqua-privy functions in a similar that typically receives waste from amanner to a septic tank whilst avoiding flush toilet.the need for a consistent water supplyto operate a flush toilet. Advantages Disadvantages The system reduces the The system comes at a level of odour and flies high cost – including the cost of landAdvantages Disadvantages The user has the Water is required (both inDoes not require a piped The system can fail to convenience of a WC quantity and reliability)water supply as a user reduce smells if the which can be locatedcan defecate directly into water seal is not indoorsthe tank maintained Permeable soil is requiredIt is a cheaper form of a Water must be available for drainageseptic tank and plentiful Requires regular emptying
Off-site sanitation systems include those in whichexcreta are collected from the individual toilets and carriedaway from the plot to be disposed off. Offsite sanitation can be classified into two maincategories:1. Decentralised systems include systems where groups of two or more houses are linked to a (small bore sewer) network leading to a communal treatment system.2. Wastewater systems serving one or several communities are termed centralised systems.
Benefits of a centralized wastewater system:- high removal of organic matter, nutrients andpathogen bacteria- good adapted to urban areasspace required for WWTP (0,5 - 2 sqm/person)- good controllabilityDisadvantages:- high cost in investment and operation- requires highly skilled personal- materials are often not locally available- high water demand - for the operation of a sewernetwork high water consumption isrequired to prevent sewer clogging.- energy and large machinery necessary
Benefits of decentralised sanitation systems− The sewer network is much simpler and lower-cost,than that of a centralizedsystem.− Also the costs in operating such a system are low,because in most cases no energyis required.− No highly skilled personal is necessary for operation.− The basic technology allows reliable operation.− A significant reduction of pollutant outputDisadvantages of Community based SanitationSystems− It needs several treatment plants - each of themneed to be operated.− The high demand in space could be a problem inurban areas.