Wastewater reuse for reforestation in Luxor, Egypt
Treated Wastewater (TWW) was reused in Luxor reforestation efforts. Around 1,700 feddan (6.8 million m²) were irrigated with TWW (category B). The practice has helped in greening deserts and in producing Jatropha and Mahogany.
While the Egyptian population is growing and the economy is expanding, renewable water supplies cannot be expanded. In the context of integrated water resources management, TWW can be applied indirectly by draining the effluent into drainage areas, as in Delta governorates. A second type of reuse involves the transfer of treated wastewater for irrigating and cultivating desert background areas of urban centres, such as the border governorates and Upper Egypt. The reuse of wastewater in irrigation in Egypt is a recent and highly restricted practice.
In the desert, the sun shines with an intensity of about 2,200 kw-hours per m2. Without regular watering, trees quickly dry out and die. Virtually no rain falls in the Egyptian desert. Piped TWW water was the only available option to reforest Luxor.
Within the case study, the area of irrigated forest was expanded from 40 feddan (160,000 m2) to 1,700 feddan (6.8 million m2) within 10 years’ time, starting in 1990. The TWW of the Luxor wastewater treatment plant was utilised for this purpose. The practice has helped in greening deserts and in producing Jatropha and Mahogany.
The ground beneath the trees is covered with a layer of dry fallen leaves that captures the sunshine, which powers tree growth. Additional fertiliser is not necessary: the effluent water delivers all the nutrients that the plants need.
Before implementing the project, groundwater samples collected from a 20-meter deep (production) well, located 1 km west of the demo site, and near the forested area, indicated no faecal contamination. After two years, coliforms were present in some of the samples taken at the on-site well. The count ranged from absent to 800 CFU/ml.
Before the expansion of the reforested area, the demo site pumped 127,000 m3 of TWW from a pond in a single year. This is equivalent to 12,700 m3 of water per feddan per year (3.17 m3 per m2 per year), assuming a total irrigated area of 10 feddan (40,000 m2).
The Jatropha plantation in Luxor has a high rate of growth and productivity. Shrubs produce seeds after 18 months of planting seedlings, compared with three years in other countries. The average yield of one tree is 3-4 kg after two years, and the older the tree grows, the more the yield increases until it reaches 12-18 kg per tree. The forest grows four times faster than European forests. Over a period of 15 years, they have already almost reached their maximum size, compared to a 60-year period in France to do the same.
The biodiesel oil produced and extracted from Luxor-grown Jatropha seeds was refined in UK laboratories, and achieves a proved higher productivity level than its counterpart in other countries.
To ensure the applicability of the practice in other areas, a nursery for producing Mahogany trees seedlings at Luxor Forest was constructed, which produces around 1 million seedlings per year.
- The targeted result has been achieved: the reforestation area was expanded from 40 feddan (160,000 m2) to 1,700 feddan (6.8 million m2) within 10 years.
- The quality of the non-conventional water resource was suitable for greening the desert and for irrigating Jatropha and Mahogany trees.
- Size of reforested area (6.8 million m2)
- Yield of trees
This case is repeatable in most of the MENA region where suitable wastewater treatment is available. Where the quality of effluent is not sufficient to irrigate food crops and vegetables, reforestation is still an option.
- An internal return rate of 15.6 percent was calculated by the project, but no specific calculations are provided.
- The cost of wastewater treatment technology, as well as operation and maintenance requirements, are claimed to be low, but no detailed values have been provided.
Dr Fatma Al Gohary
- 1. AHT Group AG, Identification and Removal of Bottlenecks for Extended Use of Wastewater for Irrigation or for other Purposes: Egypt Country Report (May 2009).
- 2. CH2MHill, Abu Rawash Wastewater Treatment Plant: Prefeasibility Study for PPP projects for Effluent Disposal (2008).
- 3. International Resources Group, Economic Feasibility Study of Using Treated Wastewater in Irrigation, LIFE Project, Report No. 33 (March 2007).
- 4. IRG, Integrated Water Resource Management II. Feasibility of Wastewater Reuse, Report NO. 14. Contract No. EPP-I-00-04-00024- 00 (June 2010).
- 5. LIFE Integrated Water Resources Management. Task Order No. 802.EPIQ II: Contract No. EPP-T-802-03-00013-00. Environmental Evaluation of Using Treated Wastewater in Agriculture: Luxor Demonstration Site (March 2008).
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