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The secondary fermentation stage is critical for stabilizing composting products and producing various secondary metabolites. However, the low metabolic rate of mesophilic bacteria is regarded as the rate-limiting stage in composting process. In present study, two indoleacetic acid (IAA)-producing bacteria (Bacillus safensis 33C and Corynebacterium stationis subsp. safensis 29B) were inoculated to strengthen the secondary fermentation stage to improve the plant-growth promoting potential of composting products. The results showed that the addition of IAA-producing bacteria promoted the assimilation of soluble salt, the condensation and aromatization of humus, and the accumulation of dissolved organic nitrogen (DON) and dissolved organic carbon (DOC). The bioaugmentation strategy also enabled faster microbial community succession during the medium-late phase of secondary fermentation. However, the colonization of Bacillus and Corynebacterium could not explain the disproportionate increase of IAA yield, which reached up to 5.6 times compared to the control group. Deeper analysis combined with physicochemical properties and microbial community structure suggested that IAA-producing bacteria might induce the increase of salinity, which enriched halotolerant bacteria capable of producing IAA, such as Halomonas, Brachybacterium and Flavobacterium. In addition, the results also proved that it was necessary to shorten secondary fermentation time to avoid IAA degradation without affecting composting maturity. In summary, enhancing secondary fermentation of composting via adding proper IAA-producing bacteria is an efficient strategy for upgrading the quality of organic fertilizer.

Nowadays, with the popularity of the computer network, we are facing to complex web service functions and rampant web attacks. In this paper, a research on web attack traceback technology is present for accurately identifying attack source, timely blocking target IP, patching service vulnerability, storing and identifying attack vectors. Existing traceback systems need to change web-based business code or architecture of server route, however, our traceback system can analyze and manage web access behaviors via proxy server, require no agent, and simulate the traceback to source of web attack with the features such as high compatibility, low performance overhead and quick traceback.

Based on the field monitoring data from the structural health monitoring system of Xihoumen Bridge, the full-scale wind field characteristics (10-min mean wind speed and direction, turbulence intensity, gust factor, wind spectrum power density, and integral length) were calculated. Moreover, the relationship between turbulence intensity and mean wind characteristics (10-min mean wind speed and mean wind direction), the relationship between gust factor and mean wind characteristics, and the relationship between gust factor and turbulence intensity were analyzed. Additionally, wind-induced responses during Typhoons Meifa, HaiKui, and Chan-hom were analyzed and compared with designed values. The analysis results can provide a basis for the formulation of emergency plans and management measures when the bridge is hit by typhoons.

The granulation process, physic-chemical properties, pollution removal ability and bacterial communities of aerobic granules with different feed-wastewater (synthetic wastewater, R1; swine wastewater, R2), and the change trend of some parameters of two types of granules in long-term operated reactors treating swine wastewater were investigated in this experiment. The result indicated that aerobic granulation with the synthetic wastewater had a faster rate compared with swine wastewater and that full granulation in R1 and R2 was reached on the 30th day and 39th day, respectively. However, although the feed wastewater also had an obvious effect on the biomass fraction and extracellular polymeric substances of the aerobic granules during the granulation process, these properties remained at a similar level after long-term operation. Moreover, a similar increasing trend could also be observed in terms of the nitrogen removal efficiencies of the aerobic granules in both reactors, and the average specific removal rates of the organics and ammonia nitrogen at the steady-state stage were 35.33 mg•g–1 VSS and 51.46 mg•g–1 VSS for R1, and 35.47 mg•g–1 VSS and 51.72 mg•g–1 VSS for R2, respectively. In addition, a shift in the bacterial diversity occurred in the granulation process, whereas bacterial communities in the aerobic granular reactor were not affected by the seed granules after long-term operation.

Biosorption can be an effective process for the removal of heavy metals from aqueous solutions. The adsorption of Cu(II) from aqueous solution on the extracellular polymers (EPS) from Bacillus sp. (named MBFF19) with respect to pH, incubation time, concentration of initial Cu(II), and biosorbent dose was studied. Biosorption of Cu(II) is highly pH dependent. The maximum uptake of Cu(II) (89.62 mg/g) was obtained at pH 4.8. Biosorption equilibrium was established in approximately 10 min. The correlation coefficient of more than 0.90 turned out that the adsorption process of Cu(II) on MBFF19 was in accordance with both Langmuir and Freundlich isotherms. The pseudo-first and second order models were applied to examine the kinetics of the adsorption, whereas the latter was found to be in harmony with the kinetic data better. Because of the outstanding uptake capacity of Cu(II), MBFF19 produced by Bacillus sp. was proved to be an excellent biosorbent for removing Cu(II) from aqueous solutions.

The effect of the pH level on the dissociative behavior of calcium ion from oyster shell was evaluated in batch experiments. The results indicated that when the initial pH changed from 3.0 to 10.0, equilibrium pH possibly maintained at about 8.0. Nitrification behaviors at various pH and NH4+-N loads were investigated simultaneously in two aerated biofilters packed with oyster shell and plastic balls, respectively. The results showed that when the influent NH4+-N concentrations varied from 15 to 60 mg l− 1, 63.6 to 97.5 percent of NH4+−N could be removed by the oyster shell biofilter, but only 13.3 to 29.0% could be removed by the plastic ball biofilter at the influent pH of 5.3∼ 5.7. Furthermore, due to the sufficient alkalinity supply in oyster shell biofilter, the effluent pH could be maintained above 6.5, indicating that oyster shell shows greater buffer capacity.

Oyster shells wastes resulting from the mariculture presents an imperative disposal problem in the coastal region. In this study, the nitrification efficiency on an aerated biofilter with raw oyster shells (ROS) as the sole buffer agent and the biomass carrier was evaluated. The capability of alkalinity supplied by ROS was found to be about 1050 mg/L, enabling a loading ammonia concentration up to 147 mg/L being removed. A substantial NH4+-N removal of 65% could be achieved even at the loading concentration as high as 240 mg•L-1. About 100% nitrification was maintained as the influent NH4+-N concentration kept below 120 mg/L. The nitrification kinetics of biofilm with ROS fit well to Monod kinetics equation. The saturation constant Km was 625 mg/L for the nitrifier with ROS, about one order of magnitude higher than that for compared plastic ball (PLB) carrier system.