Advanced Materials Research Vols. 610-613

Abstract: An aerobic denitrifying bacterium was isolated from sludge in wastewater pool. The isolate was identified by Microbial Identification System as Pseudomonas stutzeri. The bacterium isolated could degradate nitrate nitrogen, nitrite nitrogen and amonium salt nitrogen. The bacterium resulted in 82.4% NO3 – -N removal rate, 40.1% NO2 – -N removal rate and 87.9% NH4+-N removal rate respectively at 24 h in a characterization experiment. The isolate preferred to utilize sodium citrate as carbon source. Temperature was confirmed to be an important factor effecting the denitrification reaction. Optimization of reaction condition resulted in over 96% NO3 – -N removal rate after 48 h of treatment.

Abstract: A submerged membrane bioreactor (MBR) with novel material membrane was investigated to treat municipal wastewater. The results showed that better removals of the main pollutants such as CODCr, NH4⁺-N, TN and TP with removal efficiencies above 90%, 92%, 91% and 95%, respectively. The MBR permeate could meet Chinese reuse standard (GB/T 18920 2002).

Abstract: To determine the operation parameters of the expanded granular sludge bed (EGSB) reactor treating actual domestic wastewater at ambient temperature of 15-26°C, the effects of influent flow, HRT, recycle ratio,Vup and temperature on the performance of the EGSB reactor were investigated in this paper. The results indicated that when treating actual domestic wastewater, the EGSB reactor could support high influent flow and low HRT. For 9L.h-1, 11L.h-1, 15L.h-1, 24L.h-1 influent flow, with the optimal recycle ratios of 1.6-2.5, 1.2-1.6, 0.4-0.8, 0.0, the COD removal efficiencies could attain to 86-90%, 88-89%, 83%, 83%, respectively. For lower influent flow, higher Vup could slightly increase COD removal, but accordingly higher recycle ratio need to supply. Meanwhile, for higher influent flow, higher Vup will damage the granular characteristic and thus cause the decreasing of COD removal, and thus for the EGSB reactor treating actual domestic wastewater, 2.7-3.0m.h-1 optimal Vup should be employed. The EGSB reactor could work well at ambient temperature of 15°C-26°C. The optimal influent flow and Vup were 15-24L.h-1 and 3.0m.h-1. High average OLR of 18.6kgCOD.m-3.d-1 and high average COD removal efficiencies of above 81.4% could achieve, and only very low recycle ratio of 0.0 to 0.4 need employ.

Abstract: N-doping TiO₂ was prepared by sol-gel method. The XRD, BET and UV techniques were used to characterize the crystalline structure.The photocatalytic effects of Cr (VI) were studied with the fluorescence lamp illumination. The visible light-induced photocatalytic reduction mechanisms of Cr (VI) were discussed. The results showed that N-doping nano-TiO₂ increased the visible-light responsive photocatalytic activity because of the increase of the surface area and decrease the band gap. There are the optima of the dosage and pHvalue. The removal efficiency of Cr (VI) was greater than 95% when the doping amount of N was 28%, dosage was 1.5g and pH was 2.5. The photocatalytic reactions of Cr (VI) included two parts─adsorption and reduction which was the rate-controlling step. The results provide some references for the Cr (VI) control and further application of TiO2.

Abstract: Biodiesel can be made from the esterification with plant or animal fat.It has been being paid more and more attention for its characteristics of non-sulphur, non-arene,higher hexadecane and biodegradablity and renewablity Biodiesel is similar to No.0 diesel in characteristics,so it can be applied to engines directly without changing the structure.This article shows the emission performance of diesel mixed with biodiesel fuel which in different proportion,and its CO, HC and smoking exhaust have been decreased greatly,then NO_x increase slightly,while the fuel-consumption ratio remains stable(when on full load condition,5%, 15% and25% of hybrid fuel compared with pure diesel fuel,HC emission decreases by 15%,33.3% and 83.3%,and carbon smoke emission decreases by 16.25%,51.8% and 63.6%).

Abstract: Ballast water has been detected to be a great threat to marine ecosystem and human beings for threatens from biological invasion. Filtration is a kind of optimising primary method in ballast water treatment. However, so far no suitable filter has been applied considering effectiveness, economy, and resistance. A novel wall-flow structure porous ceramic filter (PCF) was adopted to combine with UV radiation. To evaluate the PCF, three types of indicator algae were filtered at different flow rates and initial alga densities. The results showed that up to 100% removal effciencies can be obtained on alga greater than 10µm and less than 50µm at the pointed alga density. The mechanism behind high removal efficiencies and high velocity were revealed as well.

Abstract: By a circular operation of anaerobic mixing - aerobic aeration – sediment drain, a sludge with low activation obtained from a common sewage treatment plant is acclimated in laboratory. The acclimation is performed with simulated sewage and composed of three periods. In the every period, the sewage concentration is successively increased, the removal percentage of COD, NH4+-N and TP are measured, when the removal is stable, the period is transformed to next one. The outside and construction characteristics of the activated sludge are observed and the protozoon is examined. Meanwhile, some influence factors such as temperature, dissolved oxygen and pH are analyzed. The experiments show that the acclimated activated sludge is able to remove the COD, NH4+-N and TP effectively under a suitable but easy-to-be obtained conditions.

Abstract: Intermediate vector polysuccinimide (PSI) was prepared by polymerization of malefic acid and ammonia at 180°Cin this article. Hydrophilic polyaspartic acid (PASP) derivative was prepared from amino-sulfonic and PSI; Lipophilic PASP derivative was prepared from PSI and diisopropylamine. Their scale inhibition rates of calcium carbonate were evaluated by static scale experiments. The inhibition rate of calcium carbonate was 90.2% when n(amino-sulfonic): n(PSI) =1:14 and the dosage of pharmaceutical was 12mg / L. The inhibition rate of calcium carbonate was 87.6% when n(diisopropylamine):n(PSI)=1:8 and the dosage of pharmaceutical was 15mg /L. The calcium carbonate that collected from static state experiments was analysised by scanning electron microscope (SEM). The results showed that polyaspartic acid derivatives were synthesized which had the best overall performance when n (amino-sulfonic): n (PSI) = 1:14.

Abstract: The sludge should have conditioning to enhance the characteristic of dewatering belong to its bad dewatering performance. The means we always use is chemical conditioning which is adding flocculants to the sludge to cooperate the machine dewatering. The single use of inorganic flocculants will increase the weight of the filtered mud cake and the results are generally not good. The synthetic organic polymer flocculants usually have good results but also have harmful effects on environment. The natural modification polymer flocculants and microbial flocculants have small adverse impact on environment with good effect in sludge dewatering and their application will be more and more widely with the development to the depth.

Abstract: A two-chambered MFC packed with activated carbon and used acrylic fiber wastewater as carbon source was constructed to study the electrical and anolyte change characteristics of the cell, the influence of activated carbon packing materials on electricity generation performance was analysed. The results indicated that microbial fuel cell could be upstart successfully when anaerobic sludge taken from wastewater treatment plants of acrylic fiber companies was used as inoculation; the maximum power density output of MFC was 211W/m3, and the internal resistance was 1311; N-contained aromatic compounds in anolyte was absorbed by activated carbon which made the cell could stably operated for a long time without renewing anolyte; anaerobic metabolism process was occurred in anode chamber, and during which N-contained aromatic compounds was degraded to amide, carboxylic acid, ammonia, etc.