Current Environmental Engineering (v.1, #1)

Preface by Jong Moon Park (1-1).

A yeast strain with high activity of phenol degradation was isolated from activated sludge of a wastewatertreatment plant in a coking chemical factory, and identified as Candida tropicalis according to the analysis of VITEK-32and its 18SrDNA gene sequence. The strain designated as JP-1 was able to grow on phenol as a sole carbon and energysource and it can degrade more than 90% of 1800 mg?L-1 phenol within 72h. The optimum pH was 6.0. Kinetic equationof phenol degradation was obtained by regression using MATLAB software. The parameters of Haldane equation werefollowing: µmax=0.387 l?hr-1, Ks=4.20 mg?L-1, KiKi =465.6 mg?L-1. Cell grew was obviously inhibition by highconcentration phenol and the inhibition strengthen increased with phenol increasing.

Selective Adsorption of Nitrate by a Macroporous Acrylic Anion Exchange Resin: Effect of the Competing Anions by Haiou Song, Changming Wang, Baijun Wang, Yeli Jiang, Zhijian Yao, Aimin Li, Rong Ma, Yang Zhou (10-16).
A novel macroporous anion exchange resin (NDP-5) has been successfully developed for selectivity removingnitrate utilizing the acrylic cross-linked polymer skeleton. The process of the nitrate adsorption onto NDP-5 resin followsthe Freundlich model, the pseudo-first-order and the pseudo-second-order kinetic models well. Compared to thecommercial resin D213, NDP-5 resin displays more preferable adsorption ability toward NO 3? from the model solution atthe presence of the competing anion (Cl?, HCO 3? or SO 42? ) at much greater levels. The contrastive experiment resultsshowed that SO 42? with the divalent negative charges has a small effect on the sorption selectivity of NDP-5 resinfunctionalized with triethylamine at the exchange sites. The equilibrium adsorption capacity of NDP-5 resin is 3.2 timeshigher than that of D213 at initial concentration with the molar ratio of 1/30 (NO 3? /SO 42? , N/N). Batch and columnadsorption demonstrated concentrations of equivalence ratio that nitrate sorbed on NDP-5 resin could result in itsconspicuous decrease. These observations pointed out that NDP-5 resin is a promising adsorbent for nitrate selectiveremoval from the model solution.

Degussa P25 powder embedded and TiO2 immobilized on activated carbon (TiO2-P25/AC) was used forphotocatalytic degradation of phenol. The effects of TiO2-P25 loading, solution pH and initial phenol concentration wereinvestigated using response surface methodology (RSM) based on central composite design (CCD). By applying thequadratic regression analysis, the polynomial expression describing the process efficiency as simultaneous functions ofthe selected independent variables was developed. Accordingly, the optimum condition was found as follows: TiO2-P25loading=2 layers, solution pH=5 and initial phenol concentration=25 mg/L. Degradation efficiency of phenol of at least99.1% was obtained experimentally under such optimal conditions, which was highly agreed with that 98.9% estimated bythe equations.

A novel photocatalytic system (MEL/TiO2/QS) based on microwave electrodeless lamp (MEL) and TiO2 filmssupported on quartz sheets (TiO2/QS) was established for high photocatalytic efficiency and long catalyst life. The resultsshowed that the degradation efficiency for reactive brilliant red X-3B in MEL/TiO2/QS was equally as that in a suspendedTiO2 system. Furthermore, under the microwave irradiation, the TiO2/QS had high catalytic activity after successivelyused 10 times without additional separation and regeneration. The pseudo-first-order kinetics was employed to describedecomposition of the dye and reaction rates at different initial dye concentrations, followed by the Langmuir-Hinshelwood kinetic model. The mineralization process and final products were also analyzed by total organic carbon(TOC) and ion chromatography (IC). The research might be useful in the commercial scale application of low cost andhigh efficiency photocatalytic process.

In order to optimize sludge depth in sand drying beds under the climatic conditions of Saudi Arabia, the effectof sludge initial depth on the physical and chemical characteristics of dried municipal sludge samples was investigated.The investigation was carried out for one year at Al-Khobar Wastewater Treatment Plant, where initial sludge depths of10, 15, 20, 25, 30 and 35 cm were implemented. Sludge samples were collected after 0, 1, 2, 4, 7, 14, and 30 days ofdrying and were analyzed for certain potential parameters such as total solids, oil and grease, and heavy metals. The studyshowed that the effect of the initial sludge depth in drying beds on the physical and chemical characteristics underinvestigation was apparent in some cases, while was not clearly demonstrated in others. As an example, the reduction ofinitial water content, in 30-day dried sludge samples, was increased from 43.8 to 51 percent as the sludge initial depth wasreduced from 35 to 10 cm, respectively. On the other hand, the effect of initial sludge depth on the pH, alkalinity, oilcontent, and concentration of heavy metals was not clear and did not show a consistent pattern.

Agro based industry such as palm oil mill generates effluent with high nutrient content. Utilisation of theeffluent as a source of nutrient for growing water hyacinth (Eichornia crassipes) could reduce the eutrophication. Then,the harvested water hyacinth can be converted into several useful products such as compost, biogas, animal feed, paper,etc. In this study, the potential of diluted treated palm oil mill effluent (DTPOME) as a source of nutrient for growingwater hyacinth (Eichornia crassipes) was evaluated. It was found that the specific growth rate for the water hyacinth is0.01834 g g-1 day-1 with removal of around 85% ammonia nitrogen (NH3-N). During experimental period, the totalsuspended solid (TSS), soluble chemical oxygen demand (COD), color, and electrical conductivity (EC) were increased.In conclusion, water hyacinth was found to have the potential in removing nutrient from diluted palm oil mill effluent butthe main problem is the presence of lignin and the decomposition by-product.

Nano-Adsorbent for Arsenates: Iron Oxyhydroxide Impregnated Microporous Activated Carbon by George Z. Kyzas, Eleni A. Deliyanni, Sotiria I. Bele, Kostas A. Matis (51-58).
Impregnation of activated carbon or oxidized activated carbon was carried out using iron(III) nitrate as startingsolution and ammonia as precipitating agent, intending the removal from aqueous solution of arsenates. The high affinityof iron oxyhydroxide nanocrystals towards inorganic arsenic species (pollutant) is widely known. Activated carbon canprovide high surface area for adsorption. The role of carbon surface chemistry and structural heterogeneity on ironoxyhydroxide, and thus on the adsorption of arsenate, was investigated. The results suggest that a microporous carbonsurface can adsorb arsenates. The higher arsenate adsorption of C1Na sample (iron impregnated with Fe(III) nitrate asstarting material and ammonia solution as precipitating agent) than the other samples. The study of the microporousmaterials was carried out by adsorption of nitrogen, FTIR spectroscopy, SEM images, XRD patterns, thermal analysis,and examination of typical laboratory adsorption isotherms.

Research on lignin biodegradation is important in the field of global carbon cycling as well as in the bleachingand pulp industries. Therefore, a laboratory scale feasibility study on the anaerobic treatment of recycled paper milleffluent (RPME) in modified anaerobic inclining-baffled reactor (MAI-BR) was conducted for a period of 180 days.However, the removal of lignin was partially evaluated at the steady state condition of three different start-ups of MAIBR.The RPME is highly polluted and characterized by its lignin content which was found in the range of 40-50 mg/L.The lignin removal was found to be 40% and 53% for the 1st and 3rd start-up, respectively. Furthermore, the 2nd start-updid not achieve lignin removal due to the floatation of palm oil mill effluent (POME) seeding sludge during the earlystage of MAI-BR start-up, respectively. Moreover, the lignin removal efficiencies increased down the reactor. Large partof lignin was removed in the first compartment. From the data of lignin removal efficiency, it was found that the reactorwas operated quite well in a short start-up time.

Application of an Activity Based Approach to Assess Air Quality from Mobile Sources in an Urban Center by Pinar Ergun, Melik Kara, Abdurrahman Bayram, Yetkin Dumanoglu, Hasan Altiok, Tolga Elbir (64-72).
An activity based emission inventory was prepared for mobile sources in an urban center, Izmir, Turkey. Thevehicles were counted and categorized into four main vehicle categories; motorcycles, passenger cars, light-duty vehiclesand heavy-duty vehicles by a portable vehicle classifier system at 19 major streets in the city. The vehicles were alsocounted continuously for 24 hours during a week in order to determine the daily and hourly fluctuations on vehiclenumbers. The seasonal changes of the vehicle numbers were also studied at all sampling points by repeating the countingcampaigns in two different weeks representing summer and winter seasons. Emissions of five main pollutants; nitrogenoxides (NOx), carbon monoxide (CO), non-methane volatile organic compounds (NMVOCs), particulate matter (PM10)and sulfur dioxide (SO2), were estimated using hourly traffic activity data on the streets and the customized emissionfactors from COPERT methodology. The CALMET/CALPUFF dispersion modeling system was also performed for theprediction of pollutant concentrations from exhaust emissions of mobile sources near the studied streets. The resultsindicated that totally 160 000-180 000 vehicles in the rush hours (08:00-09:00 am, and 18:00-19:00 pm) were active onthe streets in the city. These numbers equal to 21% of the registered vehicle fleet in the city. It was estimated that totalannual emissions were 5590 tons for CO, 754 tons for NMVOC, 2496 tons for NOx, 104 tons for PM10 and 338 tons forSO2. When these emissions were compared with the emissions emitted from industrial plants and residential heatingsources in the city, NOx emissions from traffic were found higher than the emissions from both sectors. Dispersion modelruns were mainly focused for the two episodes (August 16 and December 4, 2007) in the year 2007. According tomodeling results, maximum concentrations occurred on the streets or on a few hundred meters away from the streets.