ABSTRACT
Introduction: Colloidal materials and suspended solids cause turbidity in water. To remove turbidity, clarification method is used that includes processes of coagulation, flocculation, and sedimentation
Due to the long duration of coagulation process, coagulant aids are applied. Despite the favorable efficiency of synthetic polyelectroiytes as a coagulant aid, due to their harmful effects on human health, in this process natural organic polymers are used instead
Methods: In this research, the use of tragacanth as a natural organic coagulant aid instead of.synthetic polymers in water turbidity removal along with alum and poly aluminum chloride is studied To compare the experiments with natural conditions, Karun River water is analyzed. To complete these studies, the effects of several factors such as tragacanth concentration, the concentration of alum and poly aluminum chloride, and pH changes in average and low turbidity are investigated. Optimum pH for turbidity removal was determined by jar testing
Results: The results showed that the best pH to remove turbidity is 5.5 to 7, with the efficiency of 97.3%. At PH = 6 and at the concentration of 30 mg/L, poly ammonium chloride has maximum efficiency [90%]
Using tragacanthat concentrations of 1 and 4 mg/L along with alum at a concentration of 40 mg/L leads to turbidity removal of 81.75%
Conclusion: Using 2 and 4 mg/L of tragacanth, a significant removal efficiency is achieved in low and average turbidity.pH=7 leads to the most efficient use of tragacanth coagulant aid
ABSTRACT
Background: Reverse Osmosis [RO] is an increasingly common method of desalination. A full scale water desalination system by membrane technology [RO] evaluated in a southern city [Jask] in Iran
Methods: First, data collection on water supply and network were performed. Analysis on most of the water quality parameters [Turbidity, pH, EC, Cl[-], Na[+], Alkalinity, Ca, Na, K, No[3], No[2], Fe, Mg, Mn, NH[4], Po[4], HCo[3-], So[42-] etc.] was performed as standard methods. The membranes of the RO in the desalination system were Poly-Amid [CSM type]
Results: The efficiency of the RO water desalination system was 94.16, 84.12, 92.00, and 96.17% respectively for Turbidity, Na[+], Mg[2+], So[42-]. The result shows a significant difference between influent and effluent water of the RO system. The produced water is in agreement with national standard of drinking water. Furthermore, water exited from the RO system for TDS, Ca[+2], and Mg[2+] was less than minimum limit of the guideline
Conclusion: The quality parameters of the water resource [EC, TDS, Cl[-], Na[+] etc.] were higher than Iranian drinking water standards. The RO technology modified the quality of the water parameters
ABSTRACT
Background: Chromium is one of the toxic heavy metals that exist in trivalent and hexavalent forms in aqueous systems. Hexavalent chromium is highly toxic, carcinogenic and corrosive in nature. Adsorption is an effective method in chromium removal. The aim of this study is investigation of the hexavalent chromium removal using sugarcane bagasse from synthetic solutions and determining of the sorption kinetics.
Methods: The impact of pH, temperature, contact time, Adsorbent concentration and paricle size on chromium removal was carried out. Langmuir and Freundlich adsorption isotherms with sorption kinetics were investigated. Experiments were carried out with Tagochi method using Qualitik4.
Finding: The maximum chromium removal was achieved in pH=2, temperature of 50?C, 500 ?m adsorbent size, adsorbent concentration of 20g/l equal to 90.1%. Altogether adsorption capacity was increased with increasing temperature and adsorbent concentration and decreased with increasing pH. Adsorbent particle size does not an important effect on removal efficiency. Sugarcane bagasse adsorption kinetics in chromium removal followed by second- order reaction and were in good agreement with Langmuir isotherm.
Conclusion: the results showed appropriate adsorption capacity for sugarcane baggase in hexavalent chromium removal as a significant pollutant.