Effects of Cu（Ⅱ） and humic acid on atrazine photodegradation

This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body. The results showed that Cu(II) alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxyl radical ( OH) was a main active species. Humic acids restrained atrazine degradation, nevertheless, when introducing Cu(II), the photodegradation was accelerated, in which singlet oxygen (1O2) replaced OH acting as the prevailing species. A feasible mechanism for the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry of atrazine in the copper-polluted water.     

Production of a newly isolated Paenibacillus polymyxa biocontrol agent using monosodium glutamate wastewater and potato wastewater

A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater (MGW) and potato wastewater (PW) as culture medium. The maximum yield of 6.5 × 10 9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28°C, pH 6.0–7.5 using the mixture of MGW and PW (1:9).     

高温/中温两相厌氧消化反应中有机酸的变化

为了深入考察高温／中温两相厌氧消化的反应器系统用以处理混合基质时有机酸的变化特性,采用蒸馏－滴 测定挥发有机酸总量,并在系统达到相对稳定时用色质联机确定有机酸的组成及各自含量。研究结果表明,混合基质经高温消化后挥发有机酸含量有所增加,平均在３４６－５５２９ｍｌ／Ｌ,进一步经中国消化且系统达到稳定后其含量平均为４３－４３３ｍｇ／Ｌ,乙酸,丙酸,丁酸和戊酸是进料混合基质和高温消化后基质中主要有机酸种类     

3种短链脂肪酸对活性污泥储存PHA的影响

采用经乙酸钠驯化培养具有一定聚羟基烷酸酯(PHA)储存能力的活性污泥,考察乙酸、丙酸和丁酸3种短链脂肪酸,以及乙酸、丁酸分别与丙酸按1∶1、1∶2、2∶1比例组合成的6种混合酸作为碳源时对活性污泥中PHA的储存和转化的影响。实验结果表明,在3种短链脂肪酸中,以丁酸为碳源得到活性污泥PHA储存量最高,为40.53 mg/g;在混合酸中,乙酸与丙酸按1∶2组合时,系统PHA储存量最高,为773.4 mg/g。混合酸相对于单一的脂肪酸碳源更有利于活性污泥储存PHA。在混合酸总量一定的条件下,随着丙酸比例的增加,乙酸与丙酸混合比丁酸与丙酸混合更有利于微生物的PHA储存。     

Improved speciation of dissolved organic nitrogen in natural waters: amide hydrolysis with fluorescence derivatization

The objective of this study was to improve primary-amine nitrogen (1°-N) quantification in dissolved organic matter (DOM) originating from natural waters where inorganic forms of N, which may cause analytical interference, are commonly encountered. Efforts were targeted at elucidating organic-N structural criteria influencing the response of organic amines to known colorimetric and fluorescent reagents and exploring the use of divalent metal-assisted amide hydrolysis in combination with fluorescence analyse...     

臭氧-生物活性炭对微污染原水中典型持久性有机物的去除效果

以长三角地区J市典型有机微污染水源P水厂为研究对象,考察了臭氧-生物活性炭深度处理工艺对微污染水源水中有机物的去除效果.结果表明,臭氧-生物活性炭深度处理使高锰酸盐指数、总有机碳(TOC)和UV254的平均去除率分别提升19. 2%、10. 4%和23. 0%.水厂原水中检出8种多环芳烃(polycyclic aromatic hydrocarbon,PAHs)、16种有机氯农药(organochlorine pesticides,OCPs)、5种卤乙酸(haloacetic acids,HAAs),其总浓度分别为53. 9~100. 0、6. 5~41. 8、2. 5×103~1. 1×104ng·L~(-1),臭氧-生物活性炭深度处理对多环芳烃和有机氯农药的平均去除率分别为32. 5%和25. 9%,比常规处理工艺出水的水质有显著提升.卤乙酸的去除率为33. 8%~87. 0%,主要通过常规处理工艺去除;臭氧-生物活性炭深度处理对氯代乙酸略有去除,溴代乙酸有少量生成.     

新型全氟化合物——全氟烷基磷酸对环境影响的研究综述

全氟烷基磷酸是一种新型全氟化表面活性剂,被广泛应用于匀染剂、湿润剂和农药中的消泡添加剂等。在美国,基于对其潜在毒性的考虑,美国环境保护总署已禁止全氟烷基磷酸在粮食作物农药中使用。从全氟烷基磷酸的注册使用情况、结构与环境行为、环境介质中的浓度水平和生物暴露毒性等方面分别展开论述,旨在为中国开展该类物质的环境研究提供可借鉴依据。     

Effect of low-molecular weight organic acids on phosphorus release and phytoavailabilty of phosphorus in phosphate rocks added to soils

Phosphorus (P) is critically needed to improve soil fertility in many parts of the world. The use of water-soluble P fertilizers, e.g., single super-phosphate and triple super-phosphate in developing countries to improve crop production has been limited primarily by their high cost. The presence of indigenous phosphate deposits in some countries provides an incentive for direct application or local chemical treatment at low cost to improve the solubility of low reactive phosphate rocks (PRs). The use of naturally occurring low-molecular weight organic acids (LMWOAs) that are produced in soil as microbial metabolites or plant exudates from dead or living cells represents a new perspective in PR research. The LMWOAs contain various functional groups that may play a significant role in PR dissolution. Little information is available, however, about the potential of LMWOAs in releasing P from PRs. This study reports P release from 12 PRs, four each of low, medium, and high reactivity, obtained from various deposits (Kodjari, Tahoua, North Carolina, Gafsa, Khouribga, Tilemsi Valley, Central Florida, Sechura, Minjingu, North Florida, Hahotoe, and Parc W) using nine LMWOAs containing mono-, di-, and tri-carboxylic groups and a mineral acid (H₂SO₄). Laboratory studies showed that the organic acids are effective in releasing P from low and medium reactive PRs, but very ineffective in releasing P from high reactive PRs. The average amounts of P released by all the organic acids from the three types of PRs were 65.5 mmol kg⁻¹ PR from the low reactive PRs, 55.1 mmol kg⁻¹ from the medium, and 11.1 mmol kg⁻¹ from the high; those released from across all the PRs were 21.9 by the mono-carboxylic acid group, 54.2 by the di-carboxylic acid group, and 57.0 mmol P kg⁻¹ by the tri-carboxylic acid group. The P released was negatively correlated with the equilibrium pH, but positively correlated with Ca released from the PRs. Laboratory incubation studies on the release of P from PRs added to soils with or without organic acids and incubated at 25 °C for 15, 30, and 45 days showed that the percentage of plant-available P released varied considerably from 0.95 in the Kodjari PR to 40.1% in the North Carolina PR and was related to PR reactivity. A greenhouse study with corn (Zea mays L.) grown for 60 days on soils treated with PRs or with PRs mixed with organic acids showed that corn response to addition of oxalic or citric acid varied with P rates and PR sources, suggesting that organic acids have potential as amendments for increasing plant-available P in PR-treated soils.     

Potassium ferrate pretreatment promotes short chain fatty acids yield and antibiotics reduction in acidogenic fermentation of sewage sludge

During the acidogenic fermentation converting waste activated sludge (WAS) into short-chain fatty acids (SCFA), hydrolysis of complex organic polymers is a limiting step and the transformation of harmful substances (such as antibiotics) during acidogenic fermentation is unknown. In this study, potassium ferrate (K₂FeO₄) oxidation was used as a pretreatment strategy for WAS acidogenic fermentation to increase the hydrolysis of sludge and destruct the harmful antibiotics. Pretreatment with K₂FeO₄ can effectively increase the SCFA production during acidogenic fermentation and change the distribution of SCFA components. With the dosage of 0.2 g/g TS, the maximum SCFA yield was 4823 mg COD/L, which is 28.3 times that of the control group; acetic acid accounts for more than 90% of the total SCFA. The higher dosage (0.5 g/g TS) can further increase the proportion of acetic acid, but inhibit the overall performance of SCFA production. Apart from the promotion of hydrolysis and acidogenesis, K₂FeO₄ pretreatment can also simultaneously oxidizes and degrades part of the antibiotics in the sludge. When the dosage is 0.5 g/g TS, the degradation efficacy of antibiotics is the most significant, and the contents of ofloxacin, azithromycin, and tetracycline in the sludge are reduced by 69%, 42%, and 50%, respectively. In addition, K₂FeO₄ pretreatment can also promote the release of antibiotics from sludge flocs, which is conducive to the simultaneous degradation of antibiotics in the subsequent biological treatment process.