ABSTRACT OF THESIS
The major environment problems of this study associated with the present wastewater plant will be assessed to conduct the environmental impact assessment of the plant.
For this purpose 12 ground water samples were collected 6 samples for 500m apart and other six for 1000 m apart from the plant. These samples were tested physically, chemically and microbiologically to determine the health, agriculture and groundwater pollution. 3samples were collected from the crops which irrigated by treated wastewater and tested microbiologically to detect the reuse of treated wastewater for irrigation on the plants.
Another 2 soil samples were collected from 20 – 30cm depth from the treated wastewater irrigated soil and tested physically and chemically to investigate the effect of the irrigation on the soil.
For the crops which are tested in this study the last irrigation period may effect the zero content of both total and fecal coliform in the grape since its not irrigated for one month before sampling, while other plants ( tomato and gourd ) are irrigated before two weeks of the sampling therefore the microbiological contents are clear for both total and fecal coliform and that may be configure a health risk on peoples consuming these products.
Majority of surveyed individuals express there negative sense regarding groundwater which seem to be affected seriously due to plant existing due to contaminants percolation through soil to the groundwater because the main irrigation water source in the area is the outlet water from the plant in addition to several human – made lagoon to storage water for irrigation by farmers.
For other categories the obtained questionnaire results can be classified as follows:
Air : mainly mean the odor.
Plants : no body see any positive impact for the plant on the agricultural crops.
Animals : most of individuals believe that there is no effect on their animals due to the plant.
Disease : no effect of the plant on the health.
Insects : different opinion detected regarding this aspect.
Septic tanks : this item affect part of Sana'a that connected to the plant by sewage network.
Noise : there is no noise generated from the plant operation.
Economy : the project provides job chances for some peoples.
The physical, chemical and microbiological analysis for the groundwater indicated that the water is non-drinking water because of its non accepted taste due to high TDS concentration and also due to containing other contaminants, but it can be used for irrigation since its parameters analysis results are suitable for this purpose.
Sludge treatment step now is implemented in an open area at the rear side of the plant which cause an odors and insects in the site and the surround area.
Inspite of low hydraulic load ( inlet discharge) its better not to increase the quantity unless the inlet quality become better because the higher discharge may cause more deterioration to the outlet treated water quality due to higher organic load which affect negatively the plant efficiency.