Characterisation of biodegradable organic matter in reclaimed water using a bacterial growth fingerprint assay

2016 ◽  
Vol 16 (5) ◽  
pp. 1255-1265 ◽  
Author(s):  
Parinda Thayanukul ◽  
Futoshi Kurisu ◽  
Ikuro Kasuga ◽  
Kizuku Kanaya ◽  
Hiroaki Furumai
Keyword(s):  
Organic Matter ◽  
Bacterial Growth ◽  
Reclaimed Water ◽  
Maximum Growth ◽  
Bacterial Strains ◽  
Operational Conditions ◽  
Assimilable Organic Carbon ◽  
The Difference ◽  
Microbial Regrowth ◽  
Biodegradable Organic Matter

Microbial regrowth, microbial growth after disinfection, is an important problem that deteriorates water quality during the storage and distribution of reclaimed water. Biodegradable organic matter (BOM) that remains after water reclamation processes directly promotes microbial regrowth. In this study we propose a novel assay called the ‘bacterial growth fingerprint (BGF)’ to characterise BOM based on the maximum growth of bacterial strains, which is the extension of the conventional assimilable organic carbon assay for drinking water. Nine bacterial strains were selected from nearly 200 isolates from various reclaimed water systems. These selected bacterial strains exhibited unique substrate utilisation patterns. The BGF assay clearly reflected the difference in the quantity and quality of BOM between six different reclamation plants and the changes in BOM during a full-scale reclamation process. The information on BOM revealed by the BGF assay is useful to optimise the treatment processes or operational conditions for biologically stable reclaimed water.

A comparative study of three different assimilable organic carbon (AOC) methods: results of a round-robin test

2013 ◽  
Vol 13 (4) ◽  
pp. 1024-1033 ◽  
Author(s):  
P. S. Ross ◽  
F. Hammes ◽  
M. Dignum ◽  
A. Magic-Knezev ◽  
B. Hambsch ◽  
...  
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Bacterial Growth ◽  
Distribution Networks ◽  
Round Robin ◽  
Biological Stability ◽  
Bacterial Strains ◽  
Round Robin Test ◽  
Assimilable Organic Carbon ◽  
Wide Range

Easily assimilable organic carbon (AOC) is frequently used for the assessment of the biological stability of drinking water, which is an important consideration in the control of bacterial growth in distribution networks. The first AOC bioassay was developed in 1982 and is based on growth of two bacterial strains (Pseudomonas fluorescens P17 and Spirillum spp. NOX) in drinking water relative to their growth on acetate. Much research was subsequently conducted to modify, simplify and increase the speed of the assay which resulted in a number of alternative AOC assays. Application of these assays raises legitimate questions about the comparison of AOC data from different studies. In the present study, a round-robin test was performed to evaluate the correlation between three established AOC methods. A total of 14 water samples, covering a wide range of AOC concentrations, were analyzed with the original ‘van der Kooij’ method, the ‘Werner & Hambsch’ method and ‘Eawag’ method. Good correlations were found between AOC concentrations measured with the various methods. The data suggest an acceptable compatibility between different AOC methods, although deviations between the methods call for careful interpretation and reporting of AOC data.

Sediment and biofilm affect disinfectant decay rates during long-term operation of simulated reclaimed water distribution systems

2020 ◽  
Vol 6 (6) ◽  
pp. 1615-1626 ◽  
Author(s):  
Ni Zhu ◽  
Kris Mapili ◽  
Haniyyah Majeed ◽  
Amy Pruden ◽  
Marc A. Edwards
Keyword(s):  
Water Chemistry ◽  
Distribution Systems ◽  
Water Distribution ◽  
Reclaimed Water ◽  
Water Distribution Systems ◽  
Decay Rates ◽  
Operational Conditions ◽  
Term Operation ◽  
Microbial Regrowth

Unique water chemistry and operational conditions of reclaimed water distribution systems facilitated accumulation of sediment which resulted in depletion of disinfectants and microbial regrowth.

Reliability Analysis of Jack-Up Platforms Based on Fatigue Degradation

2002 ◽  
Author(s):  
Naser Shabakhty ◽  
Pieter van Gelder ◽  
Hotze Boonstra
Keyword(s):  
Service Time ◽  
Great Part ◽  
Fatigue Reliability ◽  
Original Design ◽  
Operational Conditions ◽  
Stress Fluctuation ◽  
The Difference ◽  
Offshore Industry ◽  
Jack Up ◽  
Load Conditions

Generally, jack-up structures are used for production drilling and exploration of hydrocarbons. The combination of mobility and the behavior as a fixed structure in operational conditions has made it an important structure in the offshore industry over the last 40 years. When a jack-up structure has been in operation for a great part of its original design-life and intention is there to extend the usage of this structure at a specific location, an investigation on fatigue degradation of the structure is an essential factor that has to be carried out before taking any decision. Fatigue is the process of damage accumulation in material due to stress fluctuation caused by variation of loads in service time. The fatigue failure occurs when accumulated damage has exceeded a critical level. In this paper, the remaining fatigue capacity of the jack-up structure is considered as an indicator for adequate use of the structure. It can be specified based on the difference between design-fatigue and fatigue experienced by the structure. The design-fatigue can be determined based on fluctuation of loads during the lifetime of the structure and experienced fatigue is specified by the load conditions, which the structure has experienced during its service time. When the information on the load conditions which the structure has experienced in its service time is available or known precisely, determination of the remaining fatigue capacity could be carried out by using the Palmgren–Miner’s rule. In practice, uncertainties are present in loads and characteristics of material. Hence it will be reasonable to determine the remaining fatigue reliability of the structure by the reliability methods. In this paper, based on a crack propagation approach and achieved information from inspection, it is shown that the remaining fatigue reliability of jack-up structures could be determined and updated by using a Bayesian procedure in the duration of the service time.

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