( 1A. Mesdaghinia, Ph.D., 1K. Naddafee, Ph.D., 1Gh. Omrani, Ph.D., 2M. Ghaneiyan, MSPH )
1- Dept. of Environmental Health Engineering , Tehran University of Medical Sciences 2- Dept. of Environmental Health , Yazd University of Medical Sciences
Keywords : Water and Wastewater Treatment , Desalination , Reverse Osmosis, Activated Sludge, Kish Abstract :
Wastewater reuse is presumably the most important measure in water resources planning and development , and it is one of the most successful strategies to overcome the problem of water shortage, in arid and semi-arid areas.
This strategy should be regarded in our country especially for regions such as Kish Island in which the problem of water supply is critical. In the Island , water treatment system includes 5 MED and 3 RO units. In 1999, water consumption per capita per day was about 315 liter and similar amount for wastewater production was 252 liter.
At present Kish Island has 5 activated sludge wastewater treatment plants (modified extended aeration) and only one of the plants is in operation.
According to the results of the examinations accomplished for drinking water characterization , the mean values of pH, EC , total hardness and alkalinity were specified to be 7.76 , 743.41 /cm,71.59 mg/l as CaCO3 and 26.78 mg/l as CaCO3 , respectively.
In this study , the values of pH , BOD5 , COD , TSS , MPN/100ml for total and fecal coliforms in raw wastewater were determined to be 7.3 , 187.4 mg/l , 305.25 mg/l , 192.43 mg/l, 2.8*107 and 3.1*106 . The same parameters have been analyzed in the effluent and are reported to be 6.97 , 55.6 mg/l , 86.28 mg/l, 30.49 mg/l, 5.4*105 and 3.8*104 , respectively.
Based on to these results , the efficiency of employed system in removing BOD , COD , TSS and coliforms were 71% , 71% , 84% and 98% , respectively.
Effect of Organic Loading Rate (OLR) on Granules Growth Rate in Upflow Anaerobic Sludge Blanket (UASB) Reactor for wastewater with High Sulfate Concentration operating continuously for a period of 350 days was examined.
In this investigation, Bidestan alcohol production factory wastewater was used as substrate with Chemical Oxygen Demand (COD) of 30000 mg/l. Anaerobic sludge from an anaerobic reactor fed with this wastewater was used as seed. The study was conducted over OLR between 1-13kg COD/m3.d by varying COD and hydraulic retention time.
The original flocculated seed converted to small granules after two weeks of using diluted wastewater and low level of OLR in the system. Granule settleability and stability were increased with increasing in OLR. Increasing OLR up to 8kg COD/m3.d caused more granule growth, while continuing for higher OLR, the growth rate slowed down and above 13 kg COD/m3.d the granules were destroyed resulting sludge washout.
High concentration of sulfide produced from sulfate ions may be attributed to this effect. Sulfide concentration, higher than 350mg/S/l caused complete washout and unstability in the reactor. Kinetic study showed that the coefficients of Y,kd, k and Ks were 0.056 g-VSS/g-COD , 0.013 l/d, 1.077 g-COD/g-VSS.d and 0.511 g-COD/l ,respectively. The high value of kd indicate the inhibiting effect of sulfide ion on methane producing bacteria growth rate.
( 1N. Jaafarzadeh, Ph.D., 2S. Nasseri, Ph.D., 2A. Mesdaghinia, Ph.D., 2 M. Shariat, Ph.D., 2 A. Mesbah, Ph.D. )
1- School of Health , Ahvaz University of Medical Sciences 2- Dept. of Environmental Health Engineering , Tehran University of Medical Sciences
In this research, with the major objective of studying the adsorption performance of short-chain organic compounds( mono-ethylene glycol ) , PAC manufactured in Iran ( with the diameter of 38 u for > 27.5% weight ) was used as the adsorbent.
At the first step , experiments on the PAC showed that it may be used efficiently for adsorbing low-molecular weight organics , because of its high active surface area(590 m2/g) , high iodine number and 6.23% as ash content.
At the second step, based on standard methods, experiments with a synthetic wastewater with the basis of mono-ethylene glycol( manufactured in Iranian Petrochemical Company ) and S.COD=800 mg/l , showed that with the optimum contact time of 9 hrs and the optimum PAC dosage of 2000 mg , more than 94% of mono-ethylene glycol adsorption on PAC may be obtained.
On the other hand, application of the data in isotherm equations of Langmuir and Freundlich, also showed that regarding K=199 , the adsorption capacity of PAC for removing mono-ethylen glycol is significant , and based on n = 11.7 , the PAC may be used efficiently in a process of suspended growth with cotinuous injection, with a high performance.
Comparision between the correlation coefficients for the Langmuir (r=0.9) and Freundlich (r=0.87) isotherms, showed a better correlation with Langmuir equation.
( 1M. Shariat, Ph.D., 2M. Ebrahimi, M.S., 2J. Hassan Nejad, 2M.Eajazi, M.S. )
1- Dept. of Environmental Health Engineering , Tehran University of Medical Sciences 2- Office of Department of Environment (Ghom)
Keywords : Assessment, Development , Ghom Abstract :
Today, sustainable exploitation of resources and justifiable and desirable operation have found special attention in development policies and is considered as the only solution to the environmental problems resulting from urban , agricultural and industrial activities.
The province of Ghom , as a new nominated state , needs a comprehensive and rational development strategy, regarding its limited ecological potentials and specific fragilities in natural ecosystems. One of the management tools is the environmental impact assessment (EIA) study.
In this survey , the Environmental Impact Assessment of different development options and thier positive and negative impacts were studied. Also, the Modified Leopold Matrix was used as the analytic method of analysis followed by a simple check-list for quick conclusion. Matrixes were ranked twice with the priorities of economic values and sustainability.
Results showed that the option of “Simultaneous Urban and Industrial Development ”may be considered as the best one, having the highest rank based on economic aspects; but, regarding the features of sustainable development and the limiting factors of ecological potential in the region, the option of “Urban Development, with Limited Industrial and Agricultural Development” obtained the highest rank to be regarded in the Development Plan for the Province of Ghom.
( 1M.R. Djahangiri, M.S., 2M. Mazaheree, Ph.D. 1S.M. Alavi )
1- School of Chemical Engineering , University of Science and Industry 2- Iranian Organization for Scientific and Technical Research
The application potential of Aspergillus niger for dye removal from textile wastewater was investigated in an airlift bioreactor. The effect of various patameters on decolorization such as temperature, pH, size of inoculum, carbon and nitrogen concentration was studied .The temperature effect on color removal was investigated in the range of 25-30'C .
The maximum decolorization was achieved at about 28'C . The pH of wastewater was adjusted on about 6, since this pH showed sound effects on color removal. Textile wastewater was riched by suitable concentrations of glucose and nitrogen. Reduction of carbon source showed that , the limiting concentration of this substrate for complete decolorization was about 5 gr/lit.
The presence of organic nitrogen in wastewater could not help the decolorization process ( its effectiveness was less than 5% ) . The maximum growth of A.niger happened in normal temperature and pH. Finally increasing the aeration rate helped the system, but remained constant considering the limiting substrate. Addition of nitrogen did not affect color removal.
Iran, regarding its special natural geographic situation and various environmental conditions, benefits significant unic biodiversity and ecosystems. From genetic diversitly point of view , about 1200 species of agricultural plants grow as native plants in Iran.
The main natural limiting factor in the country is the aridity that has made it sensitive to desertification. Hence, due to lack of rational ecological management , severe destruction of the environment and loss of biodiversity is occurred .
The total area of the northern forests in Iran , which was estimated about 3.6 million ha in 1943, decreased to 3.4 million ha. in 1959 , and to 1.9 million ha. in 1987.
Rangelands are also severely destroyed ; therefore based on international criteria, there exists no good quality ranked rangelands in Iran . Only , 15% of the lands are classified medium to good and the rest are generally weak or completely destroyed. Without any doubt, if this trend is going to be continued, a great number of plant and animal species would be extinct by the year 2020.
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