scholarly journals Evaluation of DBPs formation from SMPs exposed to chlorine, chloramine and ozone

2016 ◽  
Vol 15 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Beibei Zhang ◽  
Qiming Xian ◽  
Jian Lu ◽  
Tingting Gong ◽  
Aimin Li ◽  
...  
Keyword(s):  
Natural Organic Matter ◽  
Chlorinated Solvents ◽  
Good Alternative ◽  
Haloacetic Acids ◽  
Soluble Microbial Products ◽  
Key Factors ◽  
Factors Affecting ◽  
Important Group ◽  
Microbial Products ◽  
By Products

Soluble microbial products (SMPs) are an important group of components in wastewater effluents. In this study, the formation of disinfection by-products (DBPs), including trihalomethanes (THMs), haloacetic acids (HAAs), chlorinated solvents (CSs), haloketones (HKs), haloacetonitriles (HANs) and trichloronitromethane (TCNM) (chloropicrin), from SMPs during chlorination, chloramination and ozonation was investigated. More carbonaceous DBPs (C-DBPs: THMs, HAAs, CSs and HKs) and nitrogenous DBPs (N-DBPs: HANs and TCNM) were formed in chlorination than chloramination. More dichloroacetic and N-DBPs, and higher DBP formation potential were generated by SMPs than by natural organic matter. The results also show that disinfection factors, including temperature, pH, disinfectant dose, reaction time and bromide level significantly affected the formation of DBPs from SMPs. Additionally, the bromine incorporation factor indicates that chloramination may be a good alternative to chlorination in reducing the formation of Br-DBPs from SMPs. Bromide level and pH were the key factors affecting the formation of DBPs in both chlorination and chloramination.

Effect of silver in severely nitrified chloraminated bulk waters

2012 ◽  
Vol 12 (4) ◽  
pp. 415-421 ◽  
Author(s):  
K. C. Bal Krishna ◽  
Arumugam Sathasivan
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Control Strategy ◽  
Ph Value ◽  
Conventional Approach ◽  
Water Utilities ◽  
Soluble Microbial Products ◽  
Traditional Belief ◽  
Microbial Products ◽  
By Products

Chloramine has been widely used in many water utilities as a secondary disinfectant because of increased concern over disinfection by-products (DBPs) formation. However, its popularity has been affected due to microbial acceleration, which is traditionally believed to be by nitrifying organisms or their products such as nitrite and pH value which change substantially under nitrifying conditions. With the traditional belief in mind, the conventional approach to solve ‘chloramine decay’ was aimed at killing or flushing out nitrifiers. We have recently shown that either soluble microbial products (SMPs) released by microbes or changes in natural organic matter (NOM) characteristics under nitrified conditions could be responsible for the acceleration. With this new insight, a new control strategy was attempted by dosing silver at a concentration of 0.1 mg-Ag/L to the nitrified bulk waters obtained in a laboratory scale system. Accelerated chemical and microbial chloramine losses were significantly reduced after the addition of silver. These results are very promising for future applications.

scholarly journals Dolomitic filler in self-compacting concrete: a review

2020 ◽  
Vol 5 ◽  
pp. 75-83
Author(s):  
Ahmed Abdalqader ◽  
Mohammed Sonebi
Keyword(s):  
Key Factors ◽  
Self Compacting Concrete ◽  
Factors Affecting ◽  
Chemical Admixtures ◽  
Wide Range ◽  
Alkali Carbonate ◽  
Self Compatibility ◽  
Hardened Properties ◽  
By Products ◽  
Carbonate Reaction

The utilization of fine powders as fillers in self-compacting concrete (SCC) application is widespread, particularly in Europe. The incorporation of these fillers to attain the self-compatibility properties of SCC seems to be cheaper than the use of chemical admixtures. Among the wide range of potential fillers, dolomitic powders, particularly generated as by-products from quarry’s processing, are locally available and can be used to produce SCC. Few studies have shown that dolomitic powders can be incorporated in the SCC’s mix design, resulting in acceptable fresh and hardened properties of SCC. The particle size distribution and fineness of the dolomitic powder as well as the level of addition are the key factors affecting those properties. The influence of the chemical nature of the dolomitic powder on the properties of SCC, particularly the durability (e.g. alkali-carbonate reaction), is yet to be investigated. Furthermore, more efforts are still required to investigate the use of dolomitic by-products in the production of SCC.

Quantifying the formation of nitrogen-containing disinfection by-products in chlorinated water using absorbance and fluorescence indexes

2011 ◽  
Vol 63 (1) ◽  
pp. 40-44 ◽  
Author(s):  
P. Roccaro ◽  
F. G. A. Vagliasindi ◽  
G. V. Korshin
Keyword(s):  
Organic Matter ◽  
Reaction Time ◽  
Real Time ◽  
Natural Organic Matter ◽  
Haloacetic Acids ◽  
Real Time Monitoring ◽  
Potential Toxicity ◽  
Reaction Conditions ◽  
Drinking Waters ◽  
By Products

Among known but unregulated disinfection by-products (DBPs), several nitrogenous species (N-DBPs) have been found in drinking waters. While concentrations of N-DBP are much lower than those of trihalomethanes (THMs) and haloacetic acids (HAAs), their potential toxicity is higher. In this study the relationships between the formation of N-DBPs and the changes in NOM caused by the chlorination of raw Ancipa water quantified by the use of differential absorbance and fluorescence indexes were investigated. Very strong relationships were found between selected N-DBPs (i.e. trichloronitromethane and dichloroacetonitrile) and the proposed spectroscopic indexes that were previously developed to quantify the changes in natural organic matter (NOM) during chlorination at varying reaction conditions (chlorine dose, reaction time and temperature) and the generation of DBPs. Obtained results clearly indicate that the changes in NOM absorbance and fluorescence are fundamental descriptors of the formation of both commonly controlled halogenated DBPs and N-DBPs. This approach may be suitable for real time monitoring of emerging N-DBPs and for studying their formation pathways.

Solar photolysis of soluble microbial products as precursors of disinfection by-products in surface water

Chemosphere ◽  
2018 ◽  
Vol 201 ◽  
pp. 66-76 ◽  
Author(s):  
Jie Wu ◽  
Jian Ye ◽  
Huanlong Peng ◽  
Meirou Wu ◽  
Weiwei Shi ◽  
...  
Keyword(s):  
Surface Water ◽  
Soluble Microbial Products ◽  
Solar Photolysis ◽  
Microbial Products ◽  
By Products
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