The formation kinetics of haloacetonitriles and halonitromethanes during chloramination

2014 ◽  
Vol 14 (4) ◽  
pp. 540-546 ◽  
Author(s):  
Yi-Hsueh Chuang ◽  
Hsin-hsin Tung

This study investigates the formation of 14N- and 15N-nitrogenous disinfection by-product formation upon 15N-chloramination from four dissolved organic matters (DOMs). A series of XAD resins were used to fractionate DOM based on their hydrophobicity and functional group. The results show that hydrophobic acid (HPOA) fraction was the most important precursor pool for haloacetonitrile (HAN); these precursors mainly generated HAN through chloramine incorporation. HPOA and hydrophobic neutral (HPON) gave higher trichloronitromethane (TCNM) yields than the other fractions did. The nitrogen origin upon chloramination of HPOA was primarily from dissolved organic nitrogen (DON). By contrast, chloramines provided the main nitrogen sources during chloraminating HPON and HPOA with low DON to dissolved organic carbon ratios. The results of formation kinetics show that dichloroacetonitrile (DCAN) of which nitrogen source originate from DON formed faster than that of which nitrogen source originate from chloramines. Under normal chloramine exposure (4,000 mg-min/L, equal to 2 mg/L chloramines with around 2 days' reaction duration), 14N-DCAN concentration was two to over five times higher than that of 15N-DCAN. This study also uses a model to calculate the formation concentration of nitrogenous disinfection by-products without hydrolysis effects. The results show that 15N-DCAN formation was linearly correlated with chloramine exposure.

2015 ◽  
Vol 77 (31) ◽  
Author(s):  
Huszalina Hussin ◽  
Madihah Md Salleh ◽  
Chong Chun Siong ◽  
Muhammad Abu Naser ◽  
Suraini Abd- Aziz ◽  
...  

The recent study has demonstrated the effects of different nitrogen sources on vanillin production by Phanerochaete chrysosporium. Primary screening supported maximum biotransformation of ferulic acid (from lemongrass leaves hydrolysate) to vanillin by using ammonium chloride and yeast extract as inorganic and organic nitrogen source, respectively. With the 2-level factorial analysis, the optimum conditions of vanillin production from ferulic acid by P. chrysosporium was achieved at 0.192g/L with a molar yield of 24.5%.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Joel Romial Ngouénam ◽  
Pierre Marie Kaktcham ◽  
Chancel Hector Momo Kenfack ◽  
Edith Marius Foko Kouam ◽  
François Zambou Ngoufack

Lactic acid (LA) is used in food, cosmetic, chemical, and pharmaceutical industries and has recently attracted much attention in the production of biodegradable polymers. The expensive substances including carbon and nitrogen sources involved in its fermentative synthesis and the increasing market demand of LA have prompted scientists to look for inexpensive raw materials from which it can be produced. This research was aimed at determining the optimum conditions of lactic acid (LA) production from pineapple by-products and an inexpensive nitrogen source using Lactiplantibacillus plantarum strain 4O8. After collection and preparation of the carbon source (pineapple by-products) and nitrogen sources (by-products from fish, chicken, and beer brewing industries), they were used for the formulation of 4 different media in terms of nitrogen sources. Then, the proximate compositions of promising nitrogen sources were determined. This was followed by the screening of factors (temperature, carbon source, nitrogen source, MgSO4, MnSO4, FeSO4, KH2PO4, and KHPO4) influencing the production of LA using the definitive plan. Lastly, the optimization process was done using the central composite design. The highest LA productions ( 14.64 ± 0.05   g / l and 13.4 ± 0.02   g / l ) were obtained in production medium supplemented with chicken and fish by-products, respectively, making them the most promising sources of nitrogen. The proximate analysis of these nitrogen sources revealed that their protein contents were 83.00 ± 1.41 % DM and 74.00 ± 1.41 % DM for chicken by-products and fish by-products, respectively. Concerning the screening of factors, temperature, nitrogen source, and carbon source were the factors that showed a major impact on LA production in the production medium containing chicken by-products as nitrogen source. A pineapple by-product concentration of 141.75 g/l, a nitrogen source volume of 108.99 ml/l, and a temperature of 30.89°C were recorded as the optimum conditions for LA production. The optimization led to a 2.73-fold increase in LA production when compared with the production medium without nitrogen source. According to these results, chicken by-products are a promising and an inexpensive nitrogen source that can be an alternative to yeast extract in lactic acid production.


2015 ◽  
Vol 15 (6) ◽  
pp. 1200-1206
Author(s):  
Hsien-chun Ke ◽  
Hsin-hsin Tung

Chloramine has often been used as a chlorine alternative for trihalomethane (THM) and haloacetic acid (HAA) control. However, nitrogenous disinfection byproduct (N-DBP) formation and nitrification in distribution have always been major concerns in chloramination practices. On Kinmen Island, the high organic nitrogen content in raw water may increase the nitrogenous DBP formation. Simulated distribution system tests were conducted to explore the DBP formation kinetics in the distribution system. Lower haloacetonitrile (HAN4) formation (0.26 μg L−1) with chloramination than with chlorination (10.48 μg L−1) was observed from the 24 hours of reaction time. The nitrogen sources contributing to the dichloroacetonitrile (DCAN) formation kinetics were explored with 15N-chloramination. The results showed that nitrogen sourced from organic nitrogen was more dominant in DCAN formation with low chloramine dosage. This suggests that chloramine contributes to less DCAN formation in practice, especially for short distribution systems. In summary, the results provide evidence that simultaneous post-chloramination and pre-chlorination would be a feasible disinfection strategy applied to control regulated THM and HAA formation on Kinmen Island.


2016 ◽  
Vol 3 (1) ◽  
pp. 69-74
Author(s):  
Simeon Gavrailov ◽  
Viara Ivanova

Abstract The effects of the carbon and nitrogen substrates on the growth of Bacillus sp. SG113 strain were studied. The use of organic nitrogen sources (peptone, beef extract, yeast extract, casein) leads to rapid cellular growth and the best results for the Bacillus strain were obtained with casein hydrolysate. From the inorganic nitrogen sources studied, the (NH4) 2SO4 proved to be the best nitrogen source. Casein hydrolysate and (NH4) 2SO4 stimulated the invertase synthesis. In the presence of Jerusalem artichoke, onion and garlic extracts as carbon sources the strain synthesized from 6 to 10 times more inulinase.


1976 ◽  
Vol 54 (9) ◽  
pp. 893-899 ◽  
Author(s):  
L. M. Churchland ◽  
M. McClaren

A continuous culture system has been designed for the cultivation of certain species of marine fungi. Growth in this apparatus was compared with growth in batch culture. Growth of the three marine species tested (Zalerion maritimum, Humicola alopallonella, and Monodictys pelagica) was significantly higher in continuous culture than in batch culture.Growth of two isolates of Z. maritimum was compared on three inorganic nitrogen sources and one organic nitrogen source. Growth of the fungus in the continuous system differed both qualitatively and quantitatively from that in batch culture. Both isolates showed greater growth on the organic nitrogen source in the closed system. In the continuous system, growth was equivalent on all nitrogen sources.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jianfei Wang ◽  
Jiaqi Huang ◽  
Huanyu Guo ◽  
Shaoming Jiang ◽  
Jinyue Qiao ◽  
...  

AbstractThe effects of NaCl, Na2SO4, Na2HPO4, and Na3C6H5O7 on the production of 3-hydroxybutyrate, polyhydroxybutyrate, and by-products by Burkholderia cepacia. Proper addition of Na3C6H5O7 can significantly promote the production of 3-hydroxybutyric acid and polyhydroxybutyrate. The concentration, productivity, and yield of 3-hydroxybutyrate were increased by 48.2%, 55.6%, and 48.3% at 16 mM Na3C6H5O7. The increases of 80.1%, 47.1%, and 80.0% in the concentration, productivity, and yield of polyhydroxybutyrate were observed at 12 mM Na3C6H5O7. Na2SO4 and Na2HPO4 also have positive effects on the production capacity of 3-hydroxybutyrate and polyhydroxybutyrate within a certain range of concentration. NaCl is not conducive to the improvement of fermentation efficiency. Compared with a single nitrogen source, a mixed nitrogen source is more conducive to enhancing the production of 3-hydroxybutyrate and polyhydroxybutyrate.


Author(s):  
H. W. Harvey

Experiments have been made with the marine diatom Nitzschia closterium grown in artificial light with different nitrogen sources.After the nitrogen source in the medium was exhausted, photosynthesis and cell division continued, the cells becoming nitrogen- and chlorophylldeficient.On adding a nitrogen source to deficient cells and storing in darkness, synthesis of organic nitrogen, mostly water soluble, proceeded rapidly from ammonium, less rapidly from nitrate and very slowly from nitrite, with which it grows in light as rapidly as with nitrate or ammonium nitrogen.Possible reasons why nitrate but not nitrite is reduced in the dark are discussed.Chlorophyll and yellow pigments were synthesized in the dark by nitrogendeficient cells in quantity related to the organic nitrogen synthesized.Chlorophyll was synthesized in small amount by non-deficient cells which had been growing rapidly before transfer to darkness. Cells contained less chlorophyll when grown in moderately bright than when grown in dim light.


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