OBJECTIVETo investigate the reduction of chlorination by-products (CBPs) precursors using the fluidized-bed biofilm reactor (FBBR).

METHODSReduction of total organic carbon (TOC), ultraviolet absorbance (UV254), trihalomethane (THM) formation potential (THMFP), haloacetic acid (HAA) formation potential (HAAFP), and ammonia in FBBR were evaluated in detail. Results The reduction of TOC or UV254 was low, on average 12.6% and 4.7%, respectively, while the reduction of THMFP and HAAFP was significant. The reduction of ammonia was 30%-40% even below 3 degrees C, however, it could quickly rise to over 50% above 3degrees C. Conclusions The FBBR effectively reduces CBPs and ammonia in drinking water even at low temperature and seems to be a very promising and competitive drinking water reactor for polluted surface source waters, especially in China.

Biofilms ; Chlorine ; Water Purification

No abstract available.
Carcinoma, Squamous Cell ; Chlorine ; Photochemotherapy

OBJECTIVETo better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.

METHODSInactivation experiments of one strain Mycobacteria mucogenicum, isolated from a drinking water distribution system in South China were conducted with various chlorine disinfectants. Inactivation efficiency and disinfectant residual, as well as the formation of organic chloramines, were measured during the experiments.

RESULTSThis strain of M. mucogenicum showed high resistance to chlorine. The CT values of 99.9% inactivation by free chlorine, monochloramine and chlorine dioxide were detected as 29.6 +/- 1.46, 170 +/- 6.16, and 10.9 +/-1.55 min. (mg/L) respectively, indicating that chlorine dioxide exhibited significantly higher efficiency than free chlorine and monochloramine. It was also found that M. mucogenicum reacted with chlorine disinfectants more slowly than 5. aureus, but consumed more chlorine disinfectants during longer time of contact. Lipid analysis of the cell construction revealed that 95.7% of cell membrane lipid of M. mucogenicum was composed of saturated long chain fatty acids. Saturated fatty acids were regarded as more stable and more hydrophilic which enabled the cell membrane to prevent the diffusion of chlorine.

CONCLUSIONIt was concluded that different compositions of cell membrane might endow M. mucogenicum with a higher chlorine resistance.

Chlorine ; pharmacology ; Mycobacterium ; drug effects ; Water Microbiology

Chlorine ; Computer Simulation ; Computers, Analog ; Diffusion ; Software

The purpose of this study was to investigate effectiveness of sanitization on raw vegetables not heated in foodservice operations. Microbiological examinations of food materials and cooked food with leek Gukgalli were performed in 2 HACCP-implemented foodservices (A and B) appointed by Food and Drug Administrations, and in 2 other foodservices (C and D) not implemented HACCP. 'Washing and sanitizing raw vegetables' were monitored as CCP at A and B foodservices but only washing has been done in pre-preparation at C and D foodservices. Aerobic plate counts of received leek in A and B foodservices were above 10(7) CFU/g indicating very poor microbiological quality. After sanitization treatment (soaking for 5 minutes in chlorine water: chlorine density 50~100 ppm), its aerobic plate counts decreased to 7.06x10(5) CFU/g (A foodservice) and 4.31x10(5) CFU/g (B foodservice), coliform and faecal coliform were not detected. With this result, the effect of microbial reduction by sanitizer was conformed. But, the conditions of leek were still not acceptable by microbiological standards for ready-to-eat foods. After three more times of rinse has been done, the microbial conditions of leek became acceptable. In C and D foodservices, aerobic plate counts of leek showed decreasing trends by 2x4 times of washings but microbiological quality of leek after pre-preparation were unacceptable by microbiological standards for ready-to-eat foods (C foodservice: 3.58x10(5) CFU/g, D foodservice: 1.29x10(9) CFU/g). For the prevention of foodborne illness, sanitizing raw vegetables should be performed during pre-preparation of non-heated foods.
Chlorine ; Hazard Analysis and Critical Control Points ; Hot Temperature* ; Vegetables* ; Water

OBJECTIVES: We report two cases of anosmia that were suspected to be caused by chronic chlorine exposure in cleansing works METHODS: We examined the cases in order to assess the work-relatedness of their anosmia. We conducted olfactory threshold test and olfactory perception test repeatedly at one-month intervals. Using ion chromatography, we analyzed the detergent that the workers had been using for several years before their olfactory function decreased. RESULTS: A 59-year-old male who had worked in a cleansing process for 10 years (1983-1993) and a 58-year-old female who had worked in the same process for 8 years (1987-1995) were diagnosed with anosmia. The cause of the anosmia was presumed to have been the chlorine gas that was generated from the process of heating the detergent-dissolved water, in which chloride was detected. CONCLUSIONS: This is the first report on anosmia due to chronic chlorine exposure. Greater attention needs to be focused on the prevention of anosmia because there are many workers who have been exposed to chlorine gas in chlorine treating and generating processes.
Chlorine* ; Chromatography ; Detergents ; Female ; Heating ; Hot Temperature ; Humans ; Male ; Middle Aged ; Olfaction Disorders* ; Olfactory Perception ; Water

OBJECTIVETo investigate reductive dechlorination of 4-chlorophenol (4-CP) by nanoscale Fe0 under different conditions.

METHODSNanoscale Fe0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope (ESEM).

RESULTSThe size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate, whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover, the stability and durability of nanoscale Fe0 was evaluated through batch studies over extended periods of time.

CONCLUSIONThe nanoscale Fe0 can be used for sustainable treatment of contaminants in groundwater.

Chlorine ; chemistry ; Chlorophenols ; chemistry ; Iron ; chemistry ; Nanoparticles ; chemistry ; ultrastructure ; Temperature ; Water Pollutants, Chemical ; chemistry

OBJECTIVETo introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination.

METHODSIndicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination.

RESULTSThe sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy.

CONCLUSIONSThe possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

Chloramines ; chemistry ; pharmacology ; Chlorine ; chemistry ; Disinfection ; methods ; Halogenation ; Water ; chemistry ; Water Microbiology ; Water Purification ; methods

Amides can be obtained in good to excellent yield by Sm/TiCl(4) mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides from very simple starting materials directly.
Azo Compounds ; chemistry ; Chlorine Compounds ; chemistry ; Combinatorial Chemistry Techniques ; methods ; Halogens ; chemistry ; Samarium ; chemistry ; Titanium ; chemistry

The reactive airway dysfunction syndrome (RADS), a subset of irritant-induced asthma, has been described following exposure to various irritant gas. We describe a case of RADS occuring following a single exposure to high levels of chlorine gas in the workplace. No documented pre-existing respiratory illness and atopy was identified. Cough, dyspnea, and wheezing were developed with the single accidental exposure to chlorine gas and methacholine provocation test was positive. He was completely recovered with the treatment of corticosteroid and oxygen therapy.
Angioedema ; Asthma ; Cellulitis ; Chlorine* ; Cough ; Dyspnea ; Eosinophilia ; Hypereosinophilic Syndrome ; Methacholine Chloride ; Oxygen ; Respiratory Sounds