Environmental Science and Pollution Research - Composting has become the most important way to recycle medicinal herbal residues (MHRs). The traditional composting method, adding a microbial agent... 相似文献
Environmental Science and Pollution Research - In this study, we investigated the removal of metolachlor (MET) by biochar (BC) prepared from walnut shells (W-BC) compared with BCs made from cow... 相似文献
The phosphorus chemical industry is an important source of heavy metals in farmland. Vegetables grown on contaminated soil potentially impose adverse effects on human health. In this study, the pollution status and health risks of heavy metals in vegetables around a phosphorus chemical plant in Kaiyang County, Guizhou Province, southwestern China, were assessed, and the low-accumulation vegetables were screened by bioaccumulation factor (BAF) and cluster analysis. Results showed the average concentrations of Hg, As, Cd, Pb, Cr, Mn, Co, and Zn in vegetables were 0.015, 0.728 0.382, 0.227, 0.850, 27.227, 0.525, and 6.438 mg/kg, respectively. The single-factor pollution index showed that Cd was moderately polluted, and Cr, Hg, As, and Pb were slightly polluted. The Nemerow pollution index showed that the overall heavy metal pollution was classified as moderately polluted. The accumulation of heavy metals in different vegetables varied greatly, and chard, crown daisy, chayote, pumpkin, eggplant, white radish, sweet potato, carrot, and potato were selected as the low-accumulator vegetables. The consumption of all vegetables except chayote poses both carcinogenic and noncarcinogenic risks; among them, the consumption of sweet potato leaves has the highest health risks. The local population needs to adjust plantation structure and change dietary habits, and government should strengthen the management of phosphorus chemical plant pollution.
Monosodium glutamate (MSG) effluent was sampled from three MSG mills and 21 metal elements were measured with a inductively coupled plasma (ICP) Spectrometer. The total metal concentration of each MSG wastewater sample was 19192, 3190 and 3161 mg/L respectively. Compared with the water quality standard issued by the Chinese Government and the World Health Organization (WHO), some values were found to exceed the standards. The 24hr‐LC50, 48hr‐LC50, 72hr‐LC50 and 96hr‐LC50 to the fish Ctenopharyngodon idellus were 6.9%, 3.2%, 2.5% and 1.4% MSG wastewater individually. The specific growth rate for photosynthetic bacteria (PSB) Rhodopseudomonas sphaeroides was inhibited by the metals in MSG wastewater. Therefor the MSG wastewater should not be discharged into drinking, irrigation and fishery water systems, moreover it cannot be treated by general biological processes efficiently. How to develop an effective biotechnique for the utilization of organic pollutants in MSG effluent will also be discussed in this paper. 相似文献
China’s paper production reached 79.8 ×106 t in 2008 and ranked number one in the world. Because of its high consumption of water, energy and materials and its serious pollution, the present processes are not likely to be sustainable. An alternative, the closed Water Loop-Papermaking Integration (WLPI) method, is put forward in this paper. The WLPI method can be realized in a recycled paper mill by adding technologies and using recycled water. Many industrial case studies have shown that a large quantity of water, energy and materials can be saved, and the quantity of waste sludge and wastewater discharge was minimized by using the WLPI method. The design of the water reuse system, control of calcium hardness, water recycling and minimal waste sludge are discussed. Anaerobic technology plays an important role in the WLPI method to lower cost, energy use and waste. In the brown paper and coated white board production, zero-effluent discharge can be realized. Fresh water consumption is only 1–2 m3·t-1. For the paper mills with deinking and bleaching processes, about 10 m3·t-1 of fresh water and a similar amount of effluent discharge are needed. Power saving using anaerobic technology is 70% when recycled water is used in comparison with the conventional activated sludge process. Waste sludge can be decreased to about 5% of the initial process due to reuse of the waste sludge and the lower bio-sludge production of the anaerobic process. 相似文献
Acute toxicities (15min‐EC50) of 21 substituted benzaldehydes to Photobacterium phosphoreum were determined. A quantitative structure‐activity relationship (QSAR) was developed using molecular connectivity indices and quantum chemical parameters, which show that the toxicity is influenced mainly by the difference of the simple and valence‐corrected fourth path molecular connectivity, polarizability, dipole moment, and the most negative net atomic charge on an atom. This study further shows that benzaldehydes are reactive chemicals, which exhibit bioreactive toxicity. 相似文献
The kinetic parameters and the purification rates of the hybrid cell Foaz in soybean processing wastewater (SPW) were measured through a shaking reaction and in two automatic regulated control stable fermentation systems (ARCSFS). The maximum specific growth rate of Foaz was 0.576 h‐1, higher than that of one of its parental strains Rhodobacter sphaeroides P9479 and lower than that of another parental strain Saccharomyces cerevisiae Y9407. The BOD5 removal rate of Foaz in the No. 1 system was 61.3%, higher than those of both its parental strains when the influent BOD5 concentration was 4600 mg/L. The results of this study suggest that the hybrid Foaz has a better capacity of the degradation of organic pollutants in SPW than its parental strains and it may be applicable to the treatment of high concentration organic wastewater. 相似文献
Coal-mine gas disaster is one of the most serious coal-mine disasters in China. The main component of coal-mine gas, methane is chemically stable and very difficult to be degraded by conventional methods. Hydroxyl radical (OH), due to strong oxidizing ability and high electro-negativity, is the primary degradation source of atmospheric methane. In the present study, methane degradation using hydroxyl radicals generated by Fenton’s reagent, Fe2+/H2O2, has been carried out in the self-designed bubbling reactor. The effects of H2O2 concentration, dosage of FeSO4·7H2O and initial pH value on methane removal efficiency were investigated respectively. It has been found that the optimal reaction conditions were 100 mM of hydrogen peroxide, 2.00 mM of ferrous ion and initial pH value of 2.5. Under optimal conditions, the removal efficiency of methane reached 25% after 30 min. The preliminary experimental results unambiguously demonstrate that the degradation of methane using hydroxyl radicals generated by Fenton’s reagent is feasible. 相似文献