Iranian Journal of

Background and Objectives: Upflow Sludge Blanket Filtration (USBF) system is a modification  of the conventional activated sludge process that incorporates an anoxic zone with an upflow sludge blanket filtration clarifier in one bioreactor. It has no inherent capacity limits and is used in a wide range of applications in municipal, industrial and agricultural wastewater treatment. The main objective of this study was to evaluate the performance of a continuous USBF reactor for the treatment of sugar industrial wastewater.
Materials and Methods: Sixty liter laboratory pilot scale plant was made of plexiglass consists of   14 liter anoxic zone, 38 liter aerobic zone and 8 liter clarifier. Used molasses for raw wastewater was obtained from Varamin Sugar Company. During the study, the wastewater has been initially fed to anoxic zone of the bioreactor. It mixed with recycled activated sludge returned from the clarifier and the mixed liquor entered into aerobic zone of the bioreactor. From aeration zone, the mixed liquor passed through the sludge zone at the bottom of the clarifier which was then separated by upflow sludge blanket filtration and then the clear water discharged from the system. To complete the internal circulation loop, collected activated sludge at the bottom of the clarifier was recycled to the anoxic zone.
Results: Experimental studies indicated that average removal efficiency of COD with HRTs from 21  to 26 hours in the aerobic zone and from 8 to 10 hours in the anoxic zone were from 77 to 97 percent depended on input feed (1000 to 30000 mg/L).
Conclusion: USBF as an advanced biological process had a proper COD removal efficiency for the biological treatment of sugar industries wastewater compared to other researchers methods.

Background and Objectives: Experiments were conducted to investigate the behavior of Moving Bed Biofilm Reactor (MBBR) as a novel aerobic process for treatment of aniline synthetic wastewater as a hard biodegradable compound is commonly used in number of industrial processes. The objective of this paper is evaluation of MBBR in different conditions for treatment of aniline and determination of reaction kinetics.
Materials and Methods: In the MBBRs, different carriers are used to maximize the active biofilm surface area in the reactors. In this study, the reactor was filled with Light Expanded Clay Aggregate (LECA) as carriers. Evaluation of the reactor efficiency was done at different retention time of 8, 24, 48 and 72 hours with an influent COD from 100 to 3500 mg/L (filling ratio of 50%). After obtaining removal efficiencies, effluent concentration of aniline was measured by adsorption spectrum and maladaptive municipal wastewater treatment plant sludge in batch conditions for confidence of aniline biodegradation and its adsorption to the sludge mass.
Results:The maximum obtained removal efficiencies were 91% (influent COD=2000 mg/L) after 72 hours. Biodegradation of aniline in MBBR has been also approved by NMR spectrum tests. Finally experimental data has indicated that Grau second order model and Stover-Kincannon were the best models to describe substrate loading removal rate for aniline.
Conclusion:biological treatment of aniline wastewater compared to other researchers methods.

Backgrounds and Objectives : Nitrogen compounds in wastewater are mainly in four types of organic, am- monia, nitrite and nitrate. Total nitrogen concentration in municipal wastewater is usually within 25 to 45 mg/L as nitrogen. The most important problem with nitrogen is its oxygen demand and human health effect.
Materials and Methods: Anaerobic Baffled Reactor (ABR) is a system in which baffles are used to direct  wastewater flow. During 9 months study, a 15 liter modified ABR (104*30*15 cm) with eight baffled com- partments was used for nitrification-denitrification processes. In the seventh compartment, the wastewater was aerated to oxidize ammonia to nitrite and nitrate.
Results : Denitrification was done in the first four compartments with removal efficiency from 60 to 84 per- cent for nitrite and nitrate, respectively. During the shock loading study (4 times of the last influent), a sharp decrease in nitrogen removal rate was observed which was then returned to the previous efficiency after 11 days. Artificial neural network was used to evaluate and process the data in which the observed error in 10 patterns was less than 15 percent.
Conclusion : Anaerobic baffled reactor with an influent of up to 200 mg/L has capability to remove total  nitrogen concentration to less than the standard level of Iranian Department of Environment of 50 mg/L as nitrate and 10 mg/L as nitrogen.

Backgrounds and Objectives:Owing to the fact that the major environmental problem is production of surplus sludge in wastewater treatment plant, reducing the volume of produced sludge was objective of this research.
Materials and Methods: An anaerobic-aerobic SBR with working volume of 10 L was used to make micro-organism adapted and a polymer production reactor (PPR) with working volume of 1.5 L was used for producing polymer munisipal wastewater which contained different concentration of volatile fatty acids was consodered as the feed source (acetate and propionate) and this system was evaluated with SRT of 5, 7 and 10 days.
Results: The maximum polymer production efficiency observed within 5 days (SRT=5 days) though this efficiency was not significant in comparison with the two others time courses study. In this research the maximum polymer production efficiency at optimum condition was 25% of the sludge dry weight.
Conclusion: Experiment revealed that producing polymer from activated sludge reduced the volume of sludge and the maximum reduced sludge volume was obtained 19%.

Background and Objectives:Yazd province is located in the central desert part of Iran in which water scarcity was one of the most important problems. This has been recently solved to some extent, due to the approved channel project of water transferring from Isfahan to Yazd. Chlorination is usually used in the last stage of water treatment for disinfection in the networks, treatment plants, storages and channel stations. The possibility of carcinogen lateral composites formation is expected by tri-halo-methanes (THMs) due to the reactions occurs between the natural organic materials and free chlorine available in water. Based on the established standard by the country, the permissible limit of THMs in water is 200 mg/L. In this research, in addition to the amount of THMs and their distribution in Yazd water transferring channel and the city water network system, the important parameters and their correlations with THMs formation were discussed.
Materials and Methods: In a year of sampling period, the concentrations of THMs including the four major components of chloroform, bromoform, bromo di-chloro methane and di-bromo chloro methane during all seasons were measured using gas chromatograph and analyzed. This was done for 11 stations including Zayande-rood Basin River and Isfahan water treatment plant up to Yazd Shehneh storage, stations and inline equalization tanks and also five regions of Yazd city network.
Results: According to the results, the maximum rate of THMs (51.14 mg/L) during the sampling period in summer for Yazd city network and in ancient context of Jamea Mosque district was found. In addition, the minimum concentration of THMs was 1.60 mg/L in winter for the domestic network of the city which was related to Azad Shahr district. The Average total amount of THMs during sampling periods in all stations was 12.26 mg/L.
Conclusion: SPSS and Excel softwares were used to analyze the research data in the descriptive and inferential manner. Both statistical methods (Simple correlation coefficient, Pearson and Spearman correlation test)) with 5% significant level were considered for data analysis. The results indicated that no significant difference existed between these parameters and national and international standard scales. These rates were generally desirable and lower than standard limit which indicates acceptable operation in the treatment system and storages in the channel line of Isfahan to Yazd. Furthermore, it was obtained that there is a correlation between THMs rates and effective parameters in producing confidential values such as 95%and 99%for the residue chlorine and heat respectively. Finally the distribution and diffusion plan of THMs in transferring line and civic network of Yazd were drawn.

Background and Objectives: Many industrial effluent plants contain amounts of hard biodegradable compounds such as  β-naphthol which can be removed by conventional treatment systems. The objective of this research is to treat wastewater containing naphthalene by nano titanium oxide coated on activated carbon.
Materials and Methods: Photocatalytic experiments were carried out for different concentrations of β-naphthol using time and pH as dependent factors.  Nano TiO2 coated on activated carbone in one liter batch reactor and the resultants compounds' concentration were measured in a photocatalytic reactor  with UV-C of 12 Watt. 
Results: The experimental results indicated that UV/ nano TiO2  coated on activated carbone removed 92% of β-naphthol with concentrations of 100 mg/L within an overall elapsed time of three hours. β-naphthol total removal with concenteration of 25 mg/L was observed in two hours.
Conclusions: UV/ nano TiO2  process is very fast and effective method for removal of β-naphthol and  pH 11 was indicated as the optimum pH.