فهرست مطالب reza jalilzadeh yangejeh

Ammonia in form of ammonium ions is toxic and could decrease the dissolved oxygen in water and endanger the aquatic life. The aim of this study is the removal of ammonium using oxidation and adsorption by catalytic ozonation and clinoptilolite zeolite, respectively.

The research method is Experimental. First, optimal pH of ammonium adsorption on carbon catalyst (5 g/L), Garmsar and Firoozkooh zeolites and oxidation were determine. Then, in catalytic ozonation process, the effect of other variables on ammonium removal efficiency such as the concentration of carbonic catalyst (0.5- 50 g/L) and the reaction time were investigated. Then the effect of retention time and adsorbent concentration on adsorption of the remaining ammonium and nitrate produced by the oxidation process using zeolites and their modifications were determined.

Resuts:

 The results showed that optimum pH for the ammonium adsorption process by carbon catalyst, catalytic ozonation and zeolite was 8, 9 and 8, respectively. However, the optimum pH 4 was determined for nitrate removal. The highest ammonium absorption capacity was related to natural Firoozookh zeolite and 18.5 mg/g, and the effect of ligand and acid modification decreased 12 and 14% of absorbed capacity, respectively. It is also, the highest nitrate removal efficiency was related to Garmsar ligand modified zeolite (98%) and an absorption capacity of 11.2 mg/g. In the COP/absorption process the concentration of ammonium was decreased to 0.6 m /L.

This method effectively eliminates ammonium, and the modification of zeolite with cationic surfactant increases the efficiency of nitrate removal and the concentrates of all pollutants are brought below standards.

Hospital effluents are regarded as a kind of municipal wastewater laden with additional pollutants due to the variety of wards and therapeutic activities in a hospital. This makes the determination of kinetic coefficients and parameters of utmost importance for the successful operation and maintenance of hospital wastewater treatment facilities. Extended aeration activated sludge is one of the most important processes employed in such facilities. The present study is an effort to determine these parameters for the operation of such a facility operating in hot climate conditions. For this purpose, samples of both hospital raw wastewater and plant effluent were taken during a 6-month period from January to June 2014 to determine their BOD5, COD, TSS, PH, and Turbidity. Moreover, MLSS, MLVSS, and DO in the aeration tank as well as the sludge return ratios were measured. Such operation and maintenance parameters as θc, F/M, and SVI were then calculated and the equations of the modified Monod Model were used to calculate the values of the kinetic coefficients such as Y, K, KS, Kd, and µmax for the extended aeration activated sludge process at the hospital wastewater treatment plant as follows: K= 2.19 d-1, Ks=90.74 mg/l, Y = 0.39 g Biomass/g BOD5, Kd = 0.06 d-1, and µmax =0.85 d-1. The results obtained can be usefully exploited for designing similar extended aeration activated sludge processes for the treatment of hospital effluents, especially for those operating in hot climates.