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Photosynthetic responses to sudden exposure to high light stress (600 μmol photons m − 2 s − 1 ) and the potential for subsequent recovery were assessed in Sargassum thunbergii germlings grown under three different light intensities of 10 μmol photons m − 2 s − 1 (low light, LL), 60 μmol photons m − 2 s − 1 (moderate light, ML) and 300 μmol photons m − 2 s − 1 (high light, HL). The photosynthetic activity (maximum photochemical efficiency, F v / F m ; rapid light curves, RLCs; non-photochemical quenching, NPQ) was estimated by chlorophyll fluorescence using a pulse amplitude modulated fluorometer. All treatments exhibited high capacity for dynamic photoinhibition, with the fast reaction kinetics of F v / F m during both inhibition and recovery period, and with the rapid induction of maximum NPQ (within minutes). HL-germlings characteristically demonstrated a high NPQ value of approx. 5.5, allowing a flexible and reversible response to stress. Besides the significant contribution of NPQ to photoprotection, photosynthetic capacity (ETR max ) in LL-germlings was as great as that in HL-germlings, suggesting that energy dissipation through photochemical electron transport system could also reduce probability of photodamage. NPQ in S. thunbergii germlings appeared to be not directly controlled by a transthylakoid proton gradient (ΔpH) due to the lack of “light activated state”. Furthermore, inhibition of xanthophyll cycle with DTT considerably blocked NPQ pre induction of preillumated germlings, and a slow NPQ relaxation occurred upon disruption of ΔpH by NH 4 Cl, collectively indicating the importance of xanthophyll cycle to NPQ. These results suggested that S. thunbergii germlings could tolerate sudden high light by down-regulation of photosynthetic capacity, based on highly efficient photoprotective responses, including energy dissipation through xanthophyll cycle and photosynthetic electron transport. The photoprotection was efficiently independent on the light history of germlings. The high photosynthetic plasticity with immediate response to rapidly changing light may be a central feature explaining the survival of germlings in highly variable light environments of intertidal habitat.

In this study, a three-way factorial experimental design was used to investigate the diurnal changes of photosynthetic activity of the intertidal macroalga Sargassum thunbergii in response to temperature, tidal pattern and desiccation during a simulated diurnal light cycle. The maximum ( F v / F m ) and effective (Φ PSII ) quantum yields of photosystem II (PSII) were estimated by chlorophyll fluorescence using a pulse amplitude modulated fluorometer. Results showed that this species exhibited sun-adapted characteristics, as evidenced by the daily variation of F v / F m and Φ PSII . Both yield values decreased with increasing irradiance towards noon and recovered rapidly in the afternoon suggesting a dynamic photoinhibition. The photosynthetic quantum yield of S . thunbergii thalli varied significantly with temperature, tidal pattern and desiccation. Thalli were more susceptible to light-induced damage at high temperature of 25 °C and showed complete recovery of photosynthetic activity only when exposed to 8 °C. In contrast with the mid-morning low tide period, although there was an initial increase in photosynthetic yield during emersion, thalli showed a greater degree of decline at the end of emersion and remained less able to recover when low tide occurred at mid-afternoon. Short-term air exposure of 2 h did not significantly influence the photosynthesis. However, when exposed to moderate conditions (4 h desiccation at 15 °C or 6 h desiccation at 8 °C), a significant inhibition of photosynthesis was followed by partial or complete recovery upon re-immersion in late afternoon. Only extreme conditions (4 h desiccation at 25 °C or 6 h desiccation at 15 °C or 25 °C) resulted in the complete inhibition, with little indication of recovery until the following morning, implying the occurrence of chronic PSII damage. Based on the magnitude of effect, desiccation was the predominant negative factor affecting the photosynthesis under the simulated daytime irradiance period. These results may explain the distribution pattern of this species in natural habitats, where it is generally restricted to tide pools in the intertidal zone of wave-swept rocky shores which could provide shelter from desiccation stress during low tide.

Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of a typical secondary treatment municipal sewage treatment plant (STP) (in Hefei City) situated the beside Nanfei River, East China. The findings showed that the average concentrations of the total PBDEs in raw wastewater and treated effluent were 188.578 and 36.884 ng/L respectively. Brominated diphenyl ether (BDE) 209 congener, the predominant PBDE in the STP and Nanfei River, could be related to the discharge of car-industry-derived wastes. For PAHs, the average concentrations in raw wastewater and treated effluent were 5758.8 and 2240.4 ng/L respectively, with naphthalene, benzo[a]pyrene and indeno[1,2,3-c,d]pyrene being detected at the highest concentrations. PAHs mainly originate from the combustion of biomass/coal and petroleum. The STP reduced about 80% of the PBDEs and 61% of the PAHs, which were eliminated mainly by sedimentation processes. The removal rates of PBDEs/PAHs increased with the increase of their solid-water partitioning coefficients. Accordingly, the STP's effluent, containing some PBDE congeners (e.g., BDE 47, 99 and 209, etc.) and low-molecular-weight PAHs, could be an important contributor of these contaminants' input to Nanfei River. It resulted in a significant increase of PBDE/PAH concentrations and PAH toxicological risk in the river water downstream. About 4.040 kg/yr of PBDEs and 245.324 kg/yr of PAHs could be released into the Nanfei River. The current conventional wastewater treatment processes should be improved to remove the relatively low-molecular-weight PBDEs/PAHs more effectively.

The cell voltage and degradation rate of p-nitrophenol (PNP) were monitored in a two-chambered microbial fuel cell (MFC) system. Degradation metabolites in the anode solution of MFC were analyzed by gas chromatography–mass spectrometry (GC–MS). PNP was used as substrate by the MFC that was inoculated with anaerobic sludge. The results showed that electricity output increased with the PNP concentration increased, the MFC displayed a maximum power density of 1.778 mW m−2 and a maximum PNP degradation rate of 64.69% when PNP was used as a sole substrate. However, the cell voltage and the PNP degradation rate with sodium acetate (402.3 mV and 95.96%) were higher than those fed with glucose (341.9 mV and 83.51%) when glucose and sodium acetate were used as a substrate, respectively. Furthermore, GC–MS analysis showed that the PNP was biodegraded completely after 142 h in the MFC. These results demonstrate that PNP can be used for electricity generation in MFC for practical applications of wastewater treatment.

Dissolved organic matter obtained from landfill leachate was separated into hydrophobic acid, base, neutral (HOA, HOB, HON) and hydrophilic (HIM) fractions. Fluorescence excitation–emission matrix spectra and parallel factor analysis were employed to characterize the composition, and fluorescence quenching titration technique was applied to study the complexation between Hg (II) and HON, HOA, and HIM fractions. Protein-like substances, humic-like compounds and xenobiotic organic matters (XOM) were identified in all fractions. The HOA, HOB and HON fractions comprised mainly XOM, while the HIM fraction consisted primarily of humic-like compounds. The complexation ability of protein-like substances was higher than that of humic-like compounds. The complexation ability of the HIM was highest for protein-like substances, while the complexation ability of the HON fraction was the highest for humic-like substances. The results suggested that the toxicity and bioavailability of the mercury in the young leachates was the highest, and decreased with landfill time.

Studies of an industrial low-carbon steel (B450NbRE) suggest that the impact toughness is unexpectedly low under its practical service, probably resulting from the unstable recovery of rare earths (RE) in steelmaking. The purpose of this work is to investigate the effect of RE on the impact toughness in low-carbon steel. The B450NbRE steels with content of 0.0012–0.0180 wt.% RE were produced by vacuum induction furnace. The impact toughness and microstructure were investigated after hot rolled. The Gleeble-1500 thermal simulator was used to validate the effect of RE on the microstructure. The results indicate that the microstructure of hot-rolled steels is characterized by polygonal ferrite, quasi-polygonal ferrite, bainite and pearlite. The impact toughness increases with RE contents reaching the peak with content of 0.0047 wt.% RE, such a change exhibits the same rule as the case of the ferrite amount. However, this improvement in impact toughness is not only due to an increase in ferrite amount, but also the fine grained structure and the cleaner grain boundaries. And content of 0.0180 wt.% RE is excessive. Such an addition of the RE resulted in the martensite precipitates at the grain boundaries, which are extremely detrimental to impact toughness.

A filtration–adsorption pool train (FAPT) and drawing water (DW) system was developed to control the small urban recreational water pollution at a senior hotel in Shanghai, China. The results from one year of operation indicated that the system had successfully achieved the water quality objectives: compared with the water quality before the treatment system worked, the average concentrations of SS, CODMn, BOD5, NH3-N, TP and Chla were reduced by 79%, 39.5%, 45%, 36%, 44.3% and 70%, respectively, and DO and transparency were improved by 27% and 134%, respectively. The customers enjoyed a recreational, aesthetic and educational amenity along the ring pond. Therefore, it was conducted that the FAPT–DW system was an effective measure for small recreational waters, especially in urban areas with limited land resources.

Lignocellulosic biomass is an abundant renewable resource difficult to degrade. Its bioconversion plays important roles in carbon cycles in nature, which may be influenced by heavy metals in environment. Mycelial growth and the degradation of lignocellulosic waste by lignin-degrading fungus Phanerochaete chrysosporium under lead stress were studied. It was shown that P. chrysosporium could grow in liquid media with 400 mg L⁻¹ Pb(II), and mycelial dry weight was reduced by 54% compared to the control. Yellow mycelia in irregular short-strip shape formed in Pb-containing media, whereas the control showed ivory-white regular mycelial pellets. Two possible responses to Pb stress were: dense hyphae, and secretion from mycelia to resist Pb. During solid-state fermentation of straw, fungal colonization capability under Pb stress was positively correlated with the removal efficiency of soluble-exchangeable Pb when its content was higher than 8.2 mg kg⁻¹ dry mass. Carboxymethyl cellulase activity and cellulose degradation were inhibited at different Pb concentrations, whereas low Pb concentrations increased xylanase and ligninolytic enzyme activities and the hemicellulose and lignin degradation. Cluster analyses indicated that Pb had similar effects on the different microbial indexes related to lignin and hemicellulose degradation. The present findings will advance the understandings of lignocellulose degradation by fungi under Pb pollution, which could provide useful references for developing metal-polluted waste biotreatment technology.

Two japonica rice parents (Tong 769 and Xixuan 1) and their progenies, significantly different in protein content of grains, were investigated to reveal the activities of proteinase in leaves and glutamine synthetase in grains, as well as the dynamic changes of soluble protein content in grains during rice grain filling. The results showed that the parents were very similar in protein content, however, advanced lines with different protein contents in grains and varied activities of proteinase and glutamine synthetase were acquired by consecutively directional selection of the grain protein content in their progenies. Moreover, the enzyme activity and the protein content in grains exceeded their parents during grain filling. The protein content in grains was positively related with the proteinase activity, and the soluble protein content was negatively related with the glutamine synthetase activity in grains to some extent.

Micellar-enhanced ultrafiltration (MEUF), a surfactant-based separation process, is promising in removing heavy metal ions from aqueous solution. The retentate is the concentrated solution of surfactant and heavy metal ions retained by membrane. Two methods, chelation followed by ultrafiltration and acidification followed by ultrafiltration, were tested for separation of Cd2+ or Zn2+ from sodium dodecyl sulfate (SDS) micelles in simulated retentate solution of MEUF and the reuse of SDS. The influences of chelating agents, acid agents, pH values and molar concentration ratio of EDTA versus heavy metal ions (δ) on the recovery of SDS were studied. In the method using chelating agents, adding EDTA (δ = 1.0) at pH 4.4 was the best for separating heavy metal ions (90.1% for Cd2+, 87.1% for Zn2+) and recovering SDS (65.5% for Cd2+, 68.5% for Zn2+). The removal efficiencies of heavy metal ions were 90.3% for Cd2+, 89.6% for Zn2+ with the reclaimed SDS in MEUF. In the method using acid agents, adding H2SO4 at pH 1.0 was the best for separating heavy metal ions (98.0% for Cd2+, 96.1% for Zn2+) and recovering SDS (58.1% for Cd2+, 54.3% for Zn2+). The efficiencies of reclaimed SDS were 88.1% for removing Cd2+ and 87.8% for removing Zn2+ in MEUF.

Municipal solid waste (MSW) compost contains a significant amount of humic substances. In this study, the compost consisted of residual MSW with the metal, plastic and glass removed. In order to enhance degradation processes and the degree of composting humification, complex microorganisms (Bacillus casei, Lactobacillus buchneri and Candida rugopelliculosa) and ligno-cellulolytic (Trichoderma and White-rot fungi) microorganisms were respectively inoculated in the composting process. During the MSW composting, humic acid (HA) was extracted and purified. Elements (C, N, H, O) and spectroscopic characteristics of the HA were determined using elementary analyzer, UV, Fourier transform infrared (FTIR), and fluorescence spectroscopy. The elements analysis, UV, FTIR and fluorescence spectra all led to the same conclusion, that is inoculations with microbes led to a greater degree of aromatization of HA than in the control process (CK) with no inoculation microbes. This indicated that inoculation with microbes in composting would improve the degree humification and maturation processes, in the following order: lingo-cellulolytic>complex microorganisms>CK. And mixed inoculation of MSW with complex microorganisms and lingo-cellulolytic during composting gave a greater degree of HA aromatization than inoculation with complex microorganisms or lingo-cellulolytic alone. But comparing with the HA of soil, the HA of MSW compost revealed a lower degree of aromatization.

Micellar-enhanced ultrafiltration (MEUF) was used to remove Cd2+ from synthetic wastewater by applying polysulfone hollow fiber ultrafiltration membrane and with SDS as surfactant. The effects of some important parameters were investigated, including operating time, the concentration of SDS, transmembrane pressure, solution pH, the concentration of feed electrolyte and the mixture of SDS and Brij. The results show that the rejection of Cd2+ can reach 99%. But MEUF is not feasible when the synthetic wastewater is intensively acidic. The presence of electrolyte can decrease the efficiency of MEUF, while the mixture of SDS and Brij can increase it.

The treatment of the simulated lead-contaminated solid waste by composting with white-rot fungus was studied at laboratory scale. The composting system without the inocula of white-rot fungus was prepared as control, and the composting of the uncontaminated solid waste with the inocula of white-rot fungus was carried out as the other control. The results indicated that the solid waste inoculated with white-rot fungus could be successfully processed. The final compost was mature with 70.5% of lead (Pb) in residual fraction and none in exchangeable fraction. Germination index reached 120%. All the results indicated that the bioavailability of Pb in compost was reduced and the potential harm of Pb in compost was alleviated by composting with the inocula of white-rot fungus.

Extracellular enzymes of microorganisms play an important role in the decomposition of macromolecules in the composting process. In this study, the effects of Tween 80 and rhamnolipid on the extracellular amylase, carboxymethyl cellulose enzyme (CMCase), xylanase and protease of Penicillium simplicissimum isolated from compost were investigated during solid-state fermentation. The results showed that the enzyme activities of amylase, CMCase and xylanase were increased by Tween 80 and rhamnolipid, which, however, had a negative effect on the protease production. The stimulative effects on the three enzymes were quite different during the whole fermentation process. Tween 80 and rhamnolipid also increased the fungal biomass slightly. As a result of the enhanced enzyme activities, the organic matter were also improved to different extents by both surfactants, and the decomposition rates of hemicellulose and cellulose were increased about 8.0% and 11.6% by Tween 80 at best, respectively, as well as 5% and 5.5% by rhamnolipid.

The overall objective of this study was to investigate adsorption behavior of bisphenol A (BPA) on sediments through batch adsorption experiments. The sediment samples were collected from Xiangjiang River (Changsha, Central-south China). Data obtained from adsorption experiments show that the rapid adsorption plays the main role rather than slow adsorption in adsorption process of BPA on sediments. Freundlich model can describe the adsorption behavior of BPA on sediments very well. The calculated K(f) (mg(1-n)l(n)g(-1)) ranged from 0.0072 to 0.0178 (n ranged from 0.6944 to 0.8106). Through analyzing the data of adsorption experiments and properties of sediments, we consider that black carbon (e.g. soot- and charcoal-like material, collectively termed black carbon or BC) and hole-filling domain of the organic matters in sediment are responsible for the observed nonlinear adsorption and desorption hysteresis. The calculated hysteresis coefficient H ranged from 0.6718 to 1.0928. Negative and low molar formation enthalpy (DeltaH(0)= -5.735 kJmol(-1)) indicates that adsorption process of BPA on sediments is an exothermic reaction, attributed to the physical adsorption which is dominated by dispersive force and driven by enthalpy thoroughly. In this study, the amount of adsorbed BPA on sediment was found to decrease as sediment concentration increased, whereas it increased with an increase of ironic concentration. In acidic surroundings, the amount of adsorbed BPA on the sediment was found to decrease as pH value increased, whereas it varied indistinctively in alkaline surroundings.

A total of ten 30 m × 30 m, researching plots in Shaoshan forest from January to December of 2001 is used for this study in Hunan Province. The atmospheric deposition, the total canopy leaching, the exchange of base cations (Ca2+, Mg2+ and K+), and the uptake of H+ and N H 4 + by the canopies are estimated and quantified. The research results show that the maximal element in the total canopy leaching is Ca2+, the minimum is Mg2+ and the mid K+, with the value of 180.98 mequiv. m−2 a−1, 61.48 mequiv. m−2 a−1 and 84.13 mequiv. m−2 a−1, respectively. A conclusion significantly different from the reported results is made that is the largest leaching element in throughfall is not K+ but Ca2+ due to the special two-dimensional canopy structure and the subtropical climate with obvious seasonal characters in a year. The seasonal leaching of base cations varied greatly with the order of winter (333.72 mequiv. m−2), spring (296.80 mequiv. m−2), summer (195.49 mequiv. m−2), and autumn (166.70 mequiv. m−2), but the proportion in the total canopy leaching varied in another order of summer (64.0%), spring (59.0%), winter (57.0%), and autumn (39.2%). The seasonal uptake of N H 4 + by the canopies varied from 100 to 150 mequiv. m−2 and the H+ from 50 to 340 mequiv. m−2 in the observed year.

This paper presents a neural network predictive control scheme for studying the coagulation process of wastewater treatment in a paper mill. A multi-layer back-propagation neural network is employed to model the nonlinear relationships between the removal rates of pollutants and the chemical dosages, in order to adapt the system to a variety of operating conditions and acquire a more flexible learning ability. The system includes a neural network emulator of the reaction process, a neural network controller, and an optimization procedure based on a performance function that is used to identify desired control inputs. The gradient descent algorithm method is used to realize the optimization procedure. The results indicate that reasonable forecasting and control performances have been achieved through the developed system.