Iranica Journal of Energy & Environment
Volume:5 Issue: 2, Spring 2014

Membrane bioreactor (MBR) technology isan integrated combined system ofbiological and membrane processes to treat wastewater. MBR competently removes organic mattersand suspended solids from any type of wastewater. This study is aimed to evaluate and compare the performance of conventional and compartmentalized lab-scale MBR in treating an industrial estate wastewater (Faraman Industrial Estate, Kermanshah, Iran). The MBR systems were operated in two conditions; one in a completely stirred regime(conventional activated sludge (AS) system) and the other one in a semi plug flow regime(compartmentalized activated sludge (CAS) system). Experimental design was performed by response surface methodology (RSM) to assess the effect of two independent numerical factors i.e. hydraulic retention time (HRT) and mixed liquor volatile suspended solids (MLVSS) on nine responses.From the overall results, it was found that CAS-MBR performed better than AS-MBR.The CAS-MBR achieved 94.9 of TCOD removal efficiency at 24 h of HRT and MLVSS concentration of 10000 mg.L 1. Compared to AS MBR, CAS-MBR showed higher percentage of removal efficiency for total nitrogen andtotal Kjeldahl nitrogen. Moreover, CAS-MBR recorded the lowest SVI value of 55 mL.mg 1compared to AS-MBR. Additional microfiltration has increased the TCOD removal in both systems. As a conclusion, the CAS-MBR operated at the same condition showed higher treatment capacityin compare to AS-MBR.

An effective and economical adsorbent was prepared from the peels of Annonasquamosafor the removal of crystal violet from aqueous solutions. Adsorption studies were carried out using batch experiments. The dependence of initial dye concentration, pH, contact time, particle size and temperature on the adsorption process was studied. The crystal violet was found to be electroactive and hence electrochemical studies were also performed. The study showed that the equilibrium was achieved within 60 min for the different initial concentrations (10 to 30 mg.l). The equilibrium adsorption data were analyzed 1 using various isotherm models and they were found to fit Langmuir, Freundlich, Temkin and Harkins-Jura isotherm models in varying orders of magnitude. The maximum dye adsorption capacitiesfor cyclic voltammetry and spectral studiesat 303 K were found to be 5.6818 × 10 4 A.g 1(in terms of current)and 5×104 mg.g 1(in terms of weight),respectively. The data suggested that the adsorption kinetics was best represented by pseudo-second order kinetic model. The thermodynamic parameters including G, H and S for the adsorption process have also been evaluated using which it was concluded that the process of adsorption was spontaneous and endothermic. The cyclic voltammetricand spectral studies yielded similar results. Furthermore, statistical analysis also showed the absence of any significant difference between the two methods.

Water hammer is a transient flow in pipes that was created by sudden changes of velocity in pipe lines. This phenomenon can cause strong positive and negative pressures in water conveyance pipes and usually it poses pipeline to danger. Overall, water hammer creates by rapidly closing valves, shutting off or suddenly restarting pumps. It has destructive hydrodynamic effects in pressurized pipelines. In this study, governing equations of water hammer is numerically simulated using MATLAB software. Then, the sensitivity analysis in negative and positive pressures by changing some variables such as pipe diameter, pipe length and also wave velocity in pipe was investigated. Numerical simulation is based on characteristic method. Sensitivity analysis help designers to have well understand of water hammer phenomenon.

The present study was carried out to investigate and determine the water quality and the pollution sources affected on􀀃Semenyih River using multivariate statistical techniques and water quality index (WQI). Temperature, pH, dissolved oxygen (DO), conductivity, total dissolved solids (TDS), sulfate (SO4), nitrate 2 (NO3), nitrite (NO2), phosphate (PO4), turbidity, ammonia-nitrogen (NH3-N), total suspended solids (TSS), 3 chemical oxygen demand (COD), biochemical oxygen demand (BOD), total hardness (TH), oil and grease (O&G), Escherichia coli and total Colifor (TC) as water quality variables and Cd, Cu, Ni, Zn, Fe, Pb, Mn, Cr and Hg as heavy metals variables have been analyzed in the collected water samples during the year 2012 from 8 sampling stations along􀀃Semenyih River. Cluster analysis (CA) categorized 8 stations into three clusters based on the similarity of water quality characteristics and categorized 27 variables analyzed to four clusters to determine the relationship among the variables and their possible sources. Principal component analysis (PCA) determined that 96.63% of the total variance was accounted for five factors which pointed to the variables responsible for deterioration of water quality attributed to anthropogenic activities associated with urbanization, industrialization, agriculture, livestock husbandry and mining activities. In addition, WQI classified the river as clean (Class I) at station 1, slightly polluted (Class II) at stations 2 and 3 and as moderately polluted (Class III) at stations 4-8; in general; however, the river falls into class III and thus is required􀀃extensive treatment before using for domestic purposes. Therefore, this study verified that the multivariate statistical techniques and water quality index are mainly required for interpreting complex data sets for the purpose of analysis of water quality variations.

Commonly, there are varieties of indoor airborne particles in the foundry factories. One of the main particle with emphasize on health effect on exposed human is manganese airborne particle. The current study considered correlation between indoor psychrometric parameters and manganese concentration in the workplace. Overall, fifty samples were collected by filter based on OSHA ID-121 method in the workplaces. SPSS V.20 was used to find a predictive model using linear regression model. The mean personal exposure to manganese was 1.626 mg/m. The mean measured psychrometric 3 parameters for dry temperature, relative humidity and air velocity were 29°C, 52% and 1.2m/s, respectively. The correlations between personal exposures and indoor air parameters measurements showed a high significant relationship between personal exposure, dry temperature and wind speed in the factory (P< 0.05). This study concluded that controlling dry temperature and air velocity is the main effective parameters on airborne manganese concentration in the workplaces and decreased the personal exposure.

Recently, many researchers have explored the idea of hybrid mixed matrix membranes. Membrane separation processes based on hybrid mixed matrix membrane comprising inorganic material such as zeolite and carbon nanotubes (CNTs) embedded in polymer matrix have become one of the emerging technologies and extensively discussed in membrane separation literature. The present study is performed primarily to investigate the effect of chemical modification on carbon nanotubes surface towards gas separation performance of mixed matrix membrane. Polyethersulfone (PES)-carbon nanotubes mixed matrix membrane for modified and unmodified carbon nanotubes were casted using dry/wet phase inversion technique. The modified carbon nanotubes were prepared by treating the carbon nanotubes with acid treatment to allow PES chains to be attached to carbon nanotubes surface. The results of FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties, the productivity and purity of gas mixture compare to neat PES and unmodified carbon nanotubes mixed matrix membrane. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO2/CH4 are 32.59.

This study investigates seasonal variations in average concentrations of metals in free fall dust samples (350) collected at various sampling sites situated in five different zones of an industrial city Kota, India. Average concentrations of heavy metals (Cu, Cd, Zn and Pb) were higher in winter and lower in summer and reverse trend was observed for crustal metals (Fe, Ca and Mg). Overall, the order of average concentrations of heavy metals were Zn >Pb> Cu > Cd in both seasons.Seasonal differences in metal concentrationswere due to differences in wind direction, wind strength, temperature, relative humidity and anthropogenic activities at sampling sites. Enrichment factor and positive correlation between anthropogenic metal species such as Cu and Cd; Cu and Zn; Cu and Pb; Cd and Zn; Cd and Pb; Zn and Pb in both seasons indicate that their origin source iscommon i.e. coal combustion at thermal power station.

This study has revealed that groundnut shell can be compacted to a stabled state with binding material. The densification of the groundnut shells aid in transporting and storing, making it more economically than is possible at unprocessed state. The effects of binder (cassava starch gel) show that the highest lateral and axial expansion was 1.91 and 6% respectively. Maximum density, relax density, relaxation ratio ranges between 411 to 441 kg/m3, 201 to 202 kg/m3, 2.03 to 2.19, respectively. Other results are durability in the range of 69.89 to 93.52%, while the calorific value ranges between 19.82 to 21.97 MJ/kg. The overall, briquettes performances showed that 20% binder have the most outstanding resultin terms of durability. It was found that the amount of binder used have significant influence on the properties of the briquettes.

In this study, utilizing the obtained􀀃data from four distributed locations known as􀀃Abarkuh, Behabad, Halvan and Yazd, the solar energy potential and its characteristics in Yazd province of Iran have been evaluated. For the data, daily horizontal global radiation (HGR) and clearness index also􀀃their monthly, seasonal and yearly averaged values have been obtained. The results indicate that the four locations􀀃enjoy from 300, 294, 289 and 311 sunny and very sunny days; their yearly averaged daily clearness indexes are 0. 66, 0. 66, 0. 64 and 0. 67 and their􀀃yearly averaged daily global radiations are 20. 74, 20. 78, 19. 52 and 20. 60 MJ/m2, respectively. In overall, Yazd province enjoys from sunshine hours in almost 76% of the whole day times and its annually averaged daily HGR and clearness index are 20. 41􀀃MJ/m2 and 0. 66, respectively. Making comparison between the four nominated locations of Yazd province and 7 other selected cities around the globe, but at the same latitude, except Arizona, revealed that, their monthly mean daily global radiation and clearness index are higher than those of other􀀃six selected cities. Due to the great potential of Yazd province more funds and endeavors for solar energy development have to be devoted.

Pyrolysis liquid obtained from local suppliers in Phatthalung Province, Thailand was separated in conventional vacuum distillation into light and heavy fractions. The physiochemical characteristics and thermal behaviour of the fractionated pyrolysis liquid were investigated. It was found that light fraction had higherwater content and stronger acidity than heavy fraction and pyrolysis liquid. The heating value of light fraction was lower than those of the pyrolysis liquid and􀀃heavy fraction. The heating value of heavy portion was almost double that of the light fraction. The thermal behaviours of the pyrolysis liquid and the two fractions were determined. The light fraction had the highest decomposition rate and the lowest residual yield; in contrast to heavy fraction had slow weight loss through a wide range of temperatures and it had the highest residual yield. The chemical composition of the pyrolysis liquid and the two fractions􀀃were analysed by GC-MS. The chemical distribution differed for the fractions and the pyrolysis liquid. The light fraction was dominated by acetic acid and the heavy fraction was mainly composed phenolic compounds.

Agrochemicals nutrients and residues of pesticides in surface water and sediments samples of Weruweru sub-catchment were investigated to determine their concentrations and quality of water for human consumption. Plant nutrients NO3, NO2, NH3 and PO4 concentrations ranging from 0.005 to 0.96 mg/L were - - -3 detected in surface water samples. Pesticides residues cyanazine, -chlordane, endosulfan sulphate, p,p’-DDT, p,p’-DDD, p,p’-DDE, lindane and cypermethrin concentrations ranging from below detection limit to 45.7 μg/l and below detection limit to 157 μg/kg dw were detected in surface water samples and sediments samples, respectively. In most sites, nutrients and pesticides residues concentrations were below the maximum limits as per WHO and national limits for drinking water. The agrochemical contaminants were considered to originate from agricultural runoff and weathered agricultural soils. All parameters were measured by standard methods.

The brown seaweed Sargassum sp. is a promising feedstock for ethanol production because of its relatively high content (41.6% dry basis) of holocellulose. Chemical pretreatment of the seaweed was carried out with 1% (v/v) H2SO4 solution at 5% solid loading for 15 min at 121°C prior to saccharification with commercial cellulase. The cellulose-to-glucose conversion efficiency after 72 hours incubation was 49.84% and 61.54% for the untreated and chemically treated biomass, respectively.The algal residue after pretreatment with dilute acid was subjected to either simultaneous enzymatic saccharification and fermentation (SESF) or separate enzymatic hydrolysis and fermentation (SEHF). Saccharomyces cerevisiae was used for ethanol fermentation. The cellulose to ethanol conversions forSESF and SEHF were 66.9 and 34.1%, respectively.

Partially mixed semi-continuous reactor was used to examine the effect of organic loading rate (OLR) and hydraulic retention time (HRT) on the mesophilic anaerobic digestion of palm oil mill effluent (POME). The performance of the reactor was evaluated with emphasis on biodegradability of POME, methane gas (CH4) production rate and methane yield under different organic loading rates. The OLR of the anaerobic reactor increased stepwise from 1.0 to 6.0 g COD/L/day and HRT ranged from 13.3 to 80.0 days. The total chemical oxygen demand (TCOD) utilized was higher than 75% and the CH4 percentage of the biogas was 62.00-63.00% for the OLRs studied. The methane yield coefficient (YCH4) was inversely proportional to the OLR due to the loss of biomass with effluent. The experimental observations proved that partially mixed semi continuous reactor could perform similar to complete-mixed reactors.

The present study investigates the effectiveness of a new adsorbent prepared from agricultural wastes, namely rice husk silica as well as raw rice husk and rice bran to remove Cr +6 from aquatic solutions. The raw rice husk was collected from North of Iran. But rice husk silica was prepared by burning of clean rice husk inside a muffle furnace at a temperature of 800°C for 4 hours after acid leaching. The effects of four parameters: contact time (30 to 90 min), pH values (2 to 9), adsorbents dosages (0.5 to 1.5 g/L) and initial concentration (1.0 to 15 mg/L) were investigated to remove Cr+6. The silica derived from rice husk showed a high percentage of SiO2 up to 94.24%. But 􀁆arbon􀀃 was􀀃 the highest 􀀃element in raw rice husk up to 35.92%. The maximum removal efficiency (RE) of Cr +6 was obtained by rice bran up to 98.8% at 5.0 mg/L initial concentration of Cr, 60 min of contact time, pH = 2 and adsorbents dosage of 1.0 g/L. However, at the same condition the maximum RE by raw rice husk and rice husk silica were 82.3 and 88.4%, respectively. Moreover, a negative strong significant correlation between increasing of initial concentration of Cr+ and RE was detected by the three adsorbents (p<0.01). In conclusion, raw rice husk and adsorbents prepared from it such as rice husk silica could be considered as effective and inexpensive adsorbents for removal of Cr + from aquatic solutions.