Advanced Materials Research Vols. 113-116

Abstract: The combustion properties of five different sewage sludges were studied by thermal gravimetric analysis in the atmosphere of “oxygen”and “nitrogen + oxygen”, respectively. The results indicate that there are not influence of wastewater treatment process and the sludges anaerobic digestion on the combustion process, but both of the “anaerobic” wastewater treatment and the sludge anaerobic digestion make the ignition temperature of sludge higher, and the temperature of anaerobic digestion sludge is the highest. The relationship among the ignition temperatures of five sludges is independent of combustion atmosphere and heating rate. However, low heating rate makes the temperature of sludge decline. The combustion reaction mechanisms have been studied with Šatava-Šesták equation. It shows that there are the same combustion reaction mechanisms for five sludges in the same atmosphere, and the heating rate hasn’t influence on them, but the combustion atmosphere has influence on them.

Abstract: The properties of pyrolysis and combustion of five tars, which are produced from the gasification of five sewage sludges in the external heated downdraft reactor under the gasification temperature of 800 °C and the air flow rate of 0.05 m3/h, were studied by thermal gravimetric analysis with a heating rate of 10 °C/min in the atmosphere of nitrogen and air, respectively. The results indicate that the thermal processes of five tars in the two atmospheres can be divided into two stages. The releasing of light organic matters happens in the first stage, and there also exists the decomposition reaction during pyrolysis. The second stage is the decomposition or combustion stage of the remaining heavy organic matters for the pyrolysis or combustion. The reaction mechanisms in the two atmospheres have been studied with Coats-Redfern equation. It shows that the mechanisms of five tars in the same atmosphere are different.

Abstract: The aquatic NOM can be divided into different fractions in a wide range of molecular weight, which usually show different reactivity toward oxidants such as ozone. Fractioning natural organic matters (NOM) sourced from Songhua River with series of ultra membranes, the effect of each fraction on the degradation of BPA and NB by ozonation was investigated. The introduction of NOM fractions exept for NOM5K-10K and NOM3K-5K slightly decreased the removal efficiency of BPA which was highly reactive with ozone. On the contrary, for the refractory organic pollutant NB, NOM fractions especially the fractions with high molecular weight (NOM>10K、NOM5K-10K、NOM3K-5K、NOM1K-3K) promoted its degradation due to the enhancement of chain reaction which accompanied by the formation of hydroxyl radical, and the extent of promotion was dependent on the types and amounts of functional groups contained in NOM fractions. Even though this work is based on one type of NOM, the conclutions of this research are of general applicability.

Abstract: In order to remove ammonia-nitrogen from drinking water and reduce its threat to human health, Copper-chelex chitosan that is to be the new ammonia-nitrogen remover was prepared by chelating chitosan with copper acetate. In this paper, we measure the effect of this remover with pH= 7.5, 8.5, 9.5 and the concentration of ammonia-nitrogen, such as 1.5mg/L,2.5mg/L,5mg/L,10mg/L and 100mg/L. From the result of this experiment, we draw a conclusion that the removal efficiency of ammonia-nitrogen is about 80% when the pH is greater than 7.5 and the water inflow concentration of ammonia-nitrogen is 100mg/L. as the initial concentration ammonia-nitrogen is increasing, the removal rate is improved regularly.

Abstract: Hydrogen is a kind of ideal clean energy sources. With low energy consumption, environmental protection and other advantages, biological hydrogen production technology become the hotspot of current study home and abroad. The distribution energy technology for producing hydrogen can get hydrogen when deal with waste water. For finding out the industralized feasibility of continuous H2 bio-production,the ability of H2-production via facultative anaerobe,optimum hydraulic retention time(HRT) and optimum organic loading rate(OLR) were aslo studied. With a temperature of (35±1)°C，HRT of 8 h，the CSTR inoculated with activated sludge ,and the progression is increasing organic loading rate gradually. Six OLRs were examined, ranging from 2 to 12 g COD/L.d, with the mass of molasses ranging from 1.3 to 10 g COD/L. While COD was up to 4g/L(OLR 12kg/(m3•d)), all molasses was utilized and the H2 yield was not significantly influenced by OLR. At the intermediate COD of 6g/l (OLR 18kg/(m3•d)), the H2 yield was maximized at about 30 L/d H2 (mol molasses. Conv.), which was 17.9% and 55.9% higher than those of OLR 6 kg/(m3.d) and OLR 12 kg/(m3.d),respectively. When the influent COD concentration raised to 12g/L(OLR 30kg/(m3•d)), the reactor were overloaded, the hydrogen yield decreased drastically，hydrogen evolution rate decreased to zero. Exceeding OLR would arouse great change of internal environment parameters, such as pH, ALK(aikalinity), ORP(oxidation-reduction potential) in CSTR, and the microbial community structure would change while the metabolism of microorganism was inhibited badly.

Abstract: A laboratory-scale hybrid anaerobic baffled reactor (HABR) with five compartments using synthetic brewery wastewater as organic loading rates (OLRs) was investigated for the start-up performance and the effects of microbial community segregation on reactor start-up. Experimental results demonstrated that it was found that the COD removal efficiencies were 92~96% at 1.2 kgCOD/(m3•d) feeding over a period of 33 d, after which the reactors then successfully started. The highest percentage of CO2 in biogas was found in Compartment 1, thereafter decreased from Compartment 2 to Compartment 5 which corresponded to the increased of the percentage of CH4. It indicated that the proper anaerobic consortium in each separate compartment was developed along with specific environmental conditions, which offers the explanations that high treatment efficiency of HABR accompanied by high process stability and low operational requirements in start-up period.

Abstract: Traditional chemical-machinery producing mainly took the refiner as the primary refining equipment. Extrusion pulping was the reformation of traditional refining pulping. The different equipments and processes resulted in the different characteristics of wastewater inevitably. This article aimed to compare the characteristics and biochemical treatment methods between conventional chemical-mechanical pulping and extrusion pulping, and then discuss the biochemical treatment advantages of extrusion pulping wastewater. The result shows that: the wastewater from the extrusion pulping has lower concentration of tiny fiber, load suspended matter, wastewater temperature and effluent discharge. And thus make a simpler process, a lower cost and a better effect of the wastewater treatment.

Abstract: A full-scale integrated system of the IOC-SBBR and CWs for the biological treatment of livestock wastewater was carried out in this study, the combined IOC-SBBR process had the removal rates of COD, NH4+-N, TN reached 96.5%, 89% and 81.1%, respectively. CWs were used for the further tertiary treatment of livestock wastewater, which the average removal rate of the NH4+-N and TN was 61.3% and 60.2%, the overall integrated system was superior to the direct anaerobic or aerobic process for the treatment of large-scale livestock wastewater, would provide the valuable design and operation for the livestock wastewater treatment plants.

Abstract: Oil pollution is seriously harmful to soil environment and human health. In order to verify the physiological and biochemical response of phytoremediation to oil-contaminated soil and test the relationship between the soil activity and the rate of oil degradation, in the present study, alfalfa, ryegrass, marigold and cosmos are used as the test plants. Through observing the morphological differences, such as germination rate, seedling height and root length, of four plant species under different concentrations of oil-contaminated soil, and measuring the physiological and biochemical indexes, which including MDA, soluble sugars, free proline, soluble protein and chlorophyll etc, and the change of oil degradation rate during the growth process of plant, results proved that plants could improve self-protection capabilities to resist the oil pollution by accumulating osmoregulation substances when they were subject to oil-contaminated stress. By analyzing the changes of polyphenol oxidase, it indicated that the plants can regulate enzyme activity in the oil-contaminated soil, and enhanced it. Comprehensive comparison of the above indexes, we draw a conclusion that alfalfa is an ideal species to repair the oil-contaminated soiland Marigold is the second candidate. In general, our work will lay the theoretic basis for phytoremediation technology research.

Abstract: Land subsidence is one of the most prominent geological disasters in Xi’an, China. A review of the occurrence and development of land subsidence in Xi’an in past 50 years is given in this article. The characteristics of land subsidence in Xi'an were analyzed from time-space distribution, the development of subsidence center and its relationship with the withdrawal of groundwater. The development and characteristics of land subsidence indicate that the withdrawal of groundwater especially the confined groundwater is the major cause of land subsidence in Xi’an. Shutting down the private wells and reducing groundwater exploitation have very apparent effect on decelerating subsidence development. Limiting the exploitation and making reasonable exploitation program of groundwater are effective measures to prevent the land subsidence.