Given the characteristic of Gaza Strip’s camps, the camps can be characterized as unplanned, low income, very high population density areas. Mara (1998) stated that simplified sewerage systems are most appropriate for low-income, high- density areas that are served by on-plot level of water supply and where there are no spaces for on-site sanitation systems or for septic tanks of settled sewerage. In the camps of the Gaza Strip , the severe overcrowding within the camp and the very complicated, unplanned layout of the housing units (as shown in Section 4.1) make from on-site sanitation as well as septic tanks as unfeasible sanitation
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technologies to be provided in the camps as there are no available spaces. In addition, the very high population density within the camps will result in lower per capita cost of simplified sewerage than onsite sanitation system and this is supported by the finding of Natal; at population densities larger than 160 pe/ha, simplified sewerage becomes cheaper than on-site sanitation system (see Figure 2.2). The population density in the eight camps of the Gaza Strip is by far larger than this value (see Table 4.1). Furthermore, the water and sewerage utilities and the municipal departments lack to the sufficient knowledge related to on-site sanitation systems and in fact the sewerage systems are part of their mindset as they have a long experience in dealing with the sewerage systems installed in the urban centres in the Gaza Strip.
The water is supplied to the camps through network distribution systems (housing units have access to indoor taps) and this is best combined with a sewerage system for collecting the wastewater produced. Given the flexibility of laying simplified sewers in unplanned areas and that these camps are characterized as unplanned areas, simplified sewers can be more easily routed in these camps rather than conventional sewers. However, significant care should be taken when designing and laying simplified sewers so that sewers are laid in positions where there is no need for maintenance workers to enter the residents’ houses (due to socio-cultural aspects as shown in the previous section). Being a low-cost sewerage system (due to the flatter gradients, shallower excavation depths, the less sewer length required, the smaller diameters of the sewers and the use of simple inspection units instead of expensive large manholes) together with its ability to serve huge number of population, simplified sewerage will be a financially attractable option; from which responsible bodies in the Gaza Strip (i.e. CMWU) will more easily convince and attract international organisations or donors to provide funds for providing camps with sewerage systems; or even it will ease the establishment of reasonable cost recovery programme that is affordable for the residents. The sewerage utilities and municipal departments in the Gaza Strip are always afraid to undertake sewerage projects in camps due to the narrowness of the streets which continuously prevents the movement or the access of machineries required to excavate sewer trenches. The shallower depths of simplified sewers will eliminate the need of such machineries and that trenches excavation can be carried out by workers. High percentage of unemployed persons in the camp was construction workers inside Israel, who lost their jobs due to political situations. Getting those workers to contribute in excavating the trenches, provided there is a technical supervision, will have its affect in reducing the cost of a
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sewerage project as achieved in Orangi in Pakistan. PVC pipes of different diameters as well as concrete manholes of small diameters are commercially available in the Gaza Strip.
In term of maintenance and operation, each water and sewerage municipal department of the 25 municipalities in the Gaza Strip has its own team - comprising of engineers, technicians and workers provided with related machineries. These teams are trained to provide operation and maintenance services of the sewerage systems (conventional sewerage systems) installed in the urban centres in the Gaza Strip. Since the operation and maintenance requirements of simplified sewerage are similar to that practised with conventional sewerage, the maintenance and operation of simplified sewerage are within the capability of these municipal departments but in fact more efforts are required to improve the maintenance programmes they have. A major concern is that the large wastewater suction vehicles, owned by the municipal departments and used for cleaning the sewers and manholes, are not suitable for the camps due to the very narrow streets; however the municipal departments can overcome this by using simple flushing or cleaning equipments used for the maintenance of simplified sewerage as practised in other countries – for example, the water – jet unit mounted in a commercial van as used by CAESB in Brazil , which can be configured in the Gaza Strip. The education level also of the refugee camps residents will highly help in establishing successful schemes; which aim at explaining how the simplified sewerage system will work, what they shouldn’t dispose and what responsibilities they will have toward it; and which is essential for building effective partnership between the refugee camp communities and the municipal departments and thus ensuring the long term sustainability of the system.
5
Applicability of Natural Wastewater Treatment and
Wastewater Reuse in the Gaza Strip
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