320 likes | 510 Vues
ASPECTS OF NON-CONVENTIONAL WATER USE IN PALESTINE By Palestinian Hydrology Group Ministry of Agriculture Land Research Center Submitted to the workshop entitled Unconventional Water Use , Egypt, 6-11 December 2004 Cairo In the context of the WASAMED PROJECT.
E N D
ASPECTS OF NON-CONVENTIONAL WATER USE IN PALESTINE By Palestinian Hydrology Group Ministry of AgricultureLand Research Center Submitted to the workshop entitled Unconventional Water Use , Egypt, 6-11 December 2004 Cairo In the context of the WASAMED PROJECT
Introduction Groundwater wells constitute the only source of irrigation water in Gaza Strip. In the West Bank, wells and springs contribute almost equal amounts of irrigation water, though the vast majority of springs are concentrated in the Jordan Valley (Jericho District).
It is of paramount importance to have an idea about the amount of water available for irrigation in the West Bank and its distribution over the prospected irrigable land to have an appreciation about how important to save water for agriculture.
In this regard a GIS analysis was performed distributing the wells over land units. Land systems were selected as the land units to overlay the available wells in the West Bank. This selection is adopted to help in further analysis which would encompass other parameters related to land physical features.
Land Systems of the West Bank 1. Plain of Jenin. 2. Qalqilya Hills. 3. Tulkarm Hills 4. Nablus Heights. 5. Jerusalem-Hebron Foothills. 6. Hebron Heights 7. Jerusalem-Ramallah Heights. 8. Aldahiriya Hills. 9. Jerusalem Desert. 10. Jordan Valley. 11. Far Northeastern Height 12. Mid Northeastern Heights
West Bank Wells This map displays the distribution of wells in the West Bank. The productivity of these wells is 35 million M3/year. Palestinian wells were nearly all drilled prior to the Israeli occupation in 1967.
West Bank Springs This map displays the distribution of springs in the West Bank. The productivity of these springs is 22 million M3/year.
Investigating the amount of the available agricultural water and the irrigable land in each system, it is clear that the available water is far below the required for irrigation if we take the average amount required for cucumber greenhouses.
For example:if we fully utilize the water from wells for irrigation over each system area, the maximum area that can be irrigated by using the drip irrigation method in greenhouses once per year is in Jordan Valley and equals 27754 dunum. The available irrigable land in Jordan Valley is 87900 dunum; therefore, the percentage of the prospected irrigated area to the irrigable land is 31.6%.
This means that we are utilizing about 15.4% of the irrigable land in the West Bank
Most of the irrigated areas are concentrated in four land systems in the West Bank: the Jordan Valley (Jericho area) and the northern and western systems of Jenin, Tulkarm, Qalqilia and northeastern heights (mainly at Faraa Valley).
Wastewater Treatment Wastewater in the West Bank / Palestine is mostly disposed of in cesspits where it infiltrates into the surrounding soil. A few cases use settling tanks letting the solids to settle before the wastewater infiltrates into the soil to minimize soil clogging. On-site disposal systems are generally used, as only 20% of the population in the West Bank are connected to a sewer system. Where all rural communities and the outskirts of the cities rely on cesspits as an on-site disposal system.
Cesspits include settling of wastewater, anaerobic digestion of sludge and percolation of liquid into the ground, but the functioning of these systems usually fails after some time. The content has to be removed frequently from the filled cesspits and is currently disposed of into either the nearby open areas, wadis or existing treatment plants. The infiltration of settled wastewater into the surrounding soil and the present practice of sludge disposal affect the quality of water resources mainly the ground water.
The general shortage of water in Palestine and the problems experienced with existing on-site systems require a careful consideration of alternative solutions that can be locally applied.
The main objective of this case study is to obtain local experience with the functioning of an on-site gravel filter plant treating gray wastewater for house garden reuse purposes. Within the framework of this case study four pilot household on-site gravel filters treatment systems for single houses in Bilien Village and one collective treatment plant for twenty houses in Biet Diko village, have been monitored and sampled.
Bilien & Biet Diko Gray Wastewater Treatment Plants in Brief • four pilots Septic Tank - upflow gravel Filter plant were built in Bilien Village in Ramallah District, they receive gray wastewater from household with 6, 7, 12, 14 inhabitants. The Pilot plants were funded by The Netherlands Representative at Ramallah. • A collective gray wastewater gravel filter treatment plant was constructed at Biet-Diko. About twenty houses are connected to the treatment plant. The treatment system was funded by IDRC/Canada.
Bilien and Biet Diko villages are a typical example of a rural development that will not be sewered for many years to come, because of the population number, the comparatively low density of population and the topographical conditions with three separate topographical catchments areas which require at least three sewerage pumping stations for a centralized wastewater treatment and disposal.
Description of Household Pilot Plant Model The pilot plants are made of concrete or/and bricks. It is divided into four compartments, where the first compartment is used as septic tank and grease trap, the second and the third are used as upflow graduated gravel filter, the fourth compartment is used as a balancing tank for treated wastewater where a submersible pump is installed. The pump lifts the water to a multi-layer aerobic filter, the water pass through the layers (sand, coal, gravel) to a storage tank from where it goes to the irrigation network.
Treatment Systems Performance • Most of the samples of the gray wastewater showed no Feacal coliforms neither in the fresh gray wastewater nor in the treated gray wastewater. • Some samples from Biet-Diko fresh gray wastewater showed a small concentration of feacal coliform but it disappeared in the treated samples taken from different locations in the treatment plant. • Almost All Treatment Units (household or collective) showed a sufficient BOD or COD reduction to be reused for unrestricted irrigation.
Collective Gray wastewater Treatment plants (Biet-Diko/Jerusalem) The treatment plant consisted of anaerobic pond, gravel filter, sand filter and the polishing pond. It started to operate under anaerobic conditions on September 2000. It is connected to around 21 houses with about 180 inhabitants.
Treatment plant Description Plant site: The site is located south of Biet-Diko village with an area of 150 m2. This site is sufficient for construction of the treatment plant facilities of up to a capacity of 15 m3/d . The treatment plant would serve a sewered population of approximately 300 persons. The topography of the site has natural slope, it was adapted for the treatment units.
Conclusions • The objective of the ST-UfGF to treat wastewater for re-use has been achieved. The COD concentration of the wastewater has been reduced to less than 200 mg/L. The treated gray wastewater has been used for irrigation of the backyard trees and plants. 2. Sufficient nitrogen is available in the gray wastewater for bacteriological growth. 3. Crushed stones or washed wadi gravel of hard limestone are a good media for upflow gravel filter. 4. Gray wastewater with a COD concentration of 1270 mg/L is highly concentrated due to low water consumption.
It is recommended that: 1. Gray and black wastewater are separated for the purpose of on-site treatment and reuse of gray wastewater. 2. On-site treatment through a septic tank and upflow gravel filter system (the system used by PARC) is provided for the reuse of gray wastewater for gardening. 3. Black wastewater is directed to modified cesspit for safe and cheap disposal. 4. Alternative treatment options for the on-site reuse of wastewater should be investigated.