Wastewater Treatment Plant Study and Reuse Assessment , Case study : Al-Khobar Treatment Plant , KSA

Water conservation activities are a measure for human being development. Wastewater reuse techniques are one of the most positive water conservation applications. The current study aimed at studying Al-Khobar wastewater treatment plant and to assess the possibilities of the reclaimed wastewater reuse, securing the safe environment and human health. The study of AlKhobar treatment plant efficiency proved the suitability of using the treated wastewater as a source of water for irrigation. The Plant recorded removal percentages for the TSS that were ranged between 86.5-89.6%, the COD removal percentages were ranged between 74.878.4%, while for the BOD the records for removal percentages ranged between 94.2-97.4%. The total Coliforms, and TC showed the MPN geomean as 7.49 x 10 unit/100 ml; in the chlorinated final effluent; with 4 logs removal. Also, the fecal coliform, FC, have recorded four logs down, 4.96 x 10 unit/100 ml in the final chlorinated effluent. The coliphage, CP, have recorded a geomean of 0.64 x 10 unit/100 ml in the final treated-chlorinated effluent. The reuse of the reclaimed wastewater of Al-Khobar WWTP, according to the FAO Guidelines recorded positive enviroeconomic impacts upon the environment and human health, while the reclaimed wastewater failed microbiologically according to the Saudi’ standards. it is recommended to apply a portion of the secondary treated waste to an advanced treatment, e.g., reverse osmosis, and then to be mixed to the rest of the waste before subjected to the final chlorination. INTRODUCTION Scarcity of conventional sources of water in arid and semi-arid regions of the world has been behind the movement to find alternative or additional sources. Some of the possible sources are: deep groundwater, treated wastewater, and brackish water. Deep groundwater is not always available and can be very costly to access. Wastewater, when treated, is a relatively stable water source that has uses in agriculture, industry, recreation, gardening, industrial-plant cooling, and 41 Bull High Inst Public Health Vol.39 No.1 [2009] recharge of groundwater (1). At 2.8% Middle East and North Africa countries, MENA, has one of the highest average population growth rates in the world. Combined with scarce natural water supplies these results in very low per capita water availability, expected to decline to 725 m3 per capita, per year (pcpy), by 2025, far below the benchmark level of 1000 m3pcpy used as an indicator of severe water stress. Countries in the region which practice wastewater treatment and reuse include Kuwait, Saudi Arabia, Oman, UAE, and Egypt. However, only Tunisia, and to a certain extent, Jordan, already practice wastewater treatment and reuse as an integral component of their water management and environmental protection strategies (2). The reclaimed water as percent of total wastewater volume in some Middle East countries is recorded as 1, 1, 6, 9, and 15% in Suadi Arabia, Egypt, Jordan, Qatar, and Kuwait; respectively. A number of countries in the Middle East are planning significant increases in water reuse to meet an ultimate objective of reusing 50 to 70 percent of the total wastewater volume (3). Health risks are one of the major concerns about effluent reuse. Some risk factors are short term and vary in severity depending on the potential for human, animal or environmental contact, while others have longer term impacts that increase with increased use of reused water. The main concerns are pathogens such as viruses, bacteria, protozoa, and Helminthes, and trace organics and heavy metals, endocrine disrupting chemicals, and pharmaceutically active compounds (1). The Hyderabad Declaration on Wastewater Use in Agriculture 2002, Hyderabad; India, stated that with proper management, wastewater use contributes significantly to sustaining livelihoods, food security and the quality of the environment. In order to enhance positive outcomes while minimizing the risks of wastewater


INTRODUCTION
Bull High Inst Public Health Vol.39 No. 1 [2009]   recharge of groundwater (1) .Tunisia, and to a certain extent, Jordan, already practice wastewater treatment and reuse as an integral component of their water management and environmental protection strategies (2) .
The reclaimed water as percent of total wastewater volume in some Middle East countries is recorded as 1, 1, 6, 9, and 15% in Suadi Arabia, Egypt, Jordan, Qatar, and Kuwait; respectively.A number of countries in the Middle East are planning significant increases in water reuse to meet an ultimate objective of reusing 50 to 70 percent of the total wastewater volume (3) .
Health risks are one of the major concerns about effluent reuse.Some risk factors are short term and vary in severity depending on the potential for human, animal or environmental contact, while others have longer term impacts that increase with increased use of reused water.The main concerns are pathogens such as viruses, bacteria, protozoa, and Helminthes, and trace organics and heavy metals, endocrine disrupting chemicals, and pharmaceutically active compounds (1).Jubail, Abqaiq, and Dhahran (6) .
The current study aims at studying Al-Khobar wastewater treatment plant and to assess the possibilities of the reclaimed wastewater reuse, securing the safe environment and human health.

MATERIAL AND METHODS
For a whole year field and lab studies have to unify the results (7) .
All the collected data were pulled together to study the plant's efficiency for removal of the organic and inorganic pollutants, also, the efficiency of Microbial removal, using the appropriate statistical factors.The study's results were also been assessed on monthly basis to achieve the different impacts of the seasonal variations upon the influent and effluents; quality and quantity.
Finally, studies have been elaborated to investigate the reuse possibilities of the treated wastewater and to establish the needed guidelines for the reuse; including enviroeconomic studies.

Al Khobar Treatment Plant Description:
The

Assessment of the reuse possibilities:
The reuse of sewage effluent for agricultural practices is not an entirely new concept.WHO (1973); concluded that primary treatment would be sufficient to permit re-use for the irrigation of crops that are not for direct human consumption.
Secondary treatment and most probably disinfection and filtration are considered necessary if the effluent is to be used for irrigation of crops for direct human consumption (3) .
From the whole study it was found that the final treated chlorinated wastewater is within the guidelines of the FAO (3) , for reuse as a source of water for agricultural practices.
Scarcity of conventional sources of water in arid and semi-arid regions of the world has been behind the movement to find alternative or additional sources.Some of the possible sources are: deep groundwater, treated wastewater, and brackish water.Deep groundwater is not always available and can be very costly to access.Wastewater, when treated, is a relatively stable water source that has

At 2 .
8% Middle East and North Africa countries, MENA, has one of the highest average population growth rates in the world.Combined with scarce natural water supplies these results in very low per capita water availability, expected to decline to 725 m 3 per capita, per year (pcpy), by 2025, far below the benchmark level of 1000 m 3 pcpy used as an indicator of severe water stress.Countries in the region which practice wastewater treatment and reuse include Kuwait, Saudi Arabia, Oman, UAE, and Egypt.However, only been carried out to assess the efficiency of the WWTP, Al-Khobar WWTP, on daily and Bull High Inst Public Health Vol.39 No.1 [2009] weekly basis.The study has started with an elaborate field survey to identify the different processes and the sampling points.Unit to unit studies have been done, in order to assure the units efficiency.Also, a thoroughly follow up for the final treated wastes has been scoped to investigate the final treated wastes quality.According to the standard methods the samples were collected, preserved and analyzed.The collected samples have been studied physically, chemically and microbiologically.The Standard Methods for Water and Wastewater have been used

Figure ( 3 )
Figure (3): The removal percentages of Total Coliform, Fecal Coliform, and Coliphage after the secondary treatment and chlorination The treated effluent has failed to meet the Saudi Standards(4)  , only in the total coliform, turbidity and TSS; whereas the average values in the research have recorded 749 counts/100 ml, turbidity 27.6 NTU, and TSS 20.52 mg/l; while these factors in the Saudi standards were 220 counts/100 ml, 1 NTU, and 10 mg/l, respectively.So, it is suggested to increase the chlorination detention time or the application of a mix of Chlorine and per acetic acid, PAA.Also, it is recommended