scholarly journals Implementation of the anaerobic digestion model (ADM1) in the PHREEQC chemistry engine

2017 ◽  
Vol 76 (5) ◽  
pp. 1090-1103 ◽  
Author(s):  
Patrick Huber ◽  
Christophe Neyret ◽  
Eric Fourest
Keyword(s):  
Anaerobic Digestion ◽  
Ionic Composition ◽  
Simulation Software ◽  
Physico Chemical ◽  
Programming Effort ◽  
Water Association ◽  
Full Power ◽  
International Water ◽  
Multiple Mineral ◽  
Precipitation Phenomena

Anaerobic digestion is state-of-the-art technology to treat sludge and effluents from various industries. Modelling and optimisation of digestion operations can be advantageously performed using the anaerobic digestion model (ADM1) from the International Water Association. The ADM1, however, lacks a proper physico-chemical framework, which makes it difficult to consider wastewater of complex ionic composition and supersaturation phenomena. In this work, we present a direct implementation of the ADM1 within the PHREEQC chemistry engine. This makes it possible to handle ionic strength effects and ion-pairing. Thus, multiple mineral precipitation phenomena can be handled while resolving the ADM1. All these features can be accessed with very little programming effort, while retaining the full power and flexibility of PHREEQC. The distributed PHREEQC code can be easily interfaced with process simulation software for future plant-wide simulation of both wastewater and sludge treatment.

scholarly journals Modeling interspecific competition of the microbial community during anaerobic digestion based on cellular automata and ADM1

2021 ◽  
Author(s):  
Miao Zhang ◽  
En Shi ◽  
Yafeng Li
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Cellular Automata ◽  
Interspecific Competition ◽  
Microbial Growth ◽  
Layer Structure ◽  
Biomass Distribution ◽  
Water Association ◽  
Ca Model ◽  
International Water

Abstract Interspecific competition for substrate and space gives rise to considerable variation in biomass distribution within the microbial community. To study microbial community in depth, we employed such research methods as sampling and analytical measurements, and developed a cellular automata (CA) model that would facilitates description of the microbial growth process based on the Anaerobic Digestion Model No. 1 (ADM1) of the International Water Association (IWA). Using the CA model, we aimed to determine whether interspecific competition occurs among acidogens, acetogens and methanogens, and examine the influence of interspecific competition on the spatial structure of microbial communities. We found that acetogens and methanogens competed for core space, resulting in a multi-layer structure. Butyrate-degrading acetogens increased in number, resulting in inhibition of propionate-degrading acetogens. Hydrogenotrophic methanogens showed stronger competitive advantage than acetotrophic methanogens. The simulation showed that the multi-layer structure of the microbial community was formed by interspecific competition.

PENGARUH UPAH MINUMUM TERHADAP TENAGA KERJA DI NEGARA DENGAN TINGKAT PENGHASILAN RATA-RATA YANG RENDAH

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Veny Anindya Puspitasari
Keyword(s):  
Minimum Wage ◽  
Basic Needs ◽  
Wage Policy ◽  
Average Income ◽  
Income Per Capita ◽  
Unskilled Workers ◽  
Water Association ◽  
International Water ◽  
Per Capita ◽  
Association Data

<p>The minimum wage is a macroeconomic issue that is still debated, Basically, the minimum wage policy aimed to protect workers, so that thet earn an adequate wages to finance the basic needs of their life. Practically, the minimum wage policy often encounters its purpose because it is regarged as miserable for those who have no expertise. This phenomenon is mainly happening in the low –avegrage- income countries that have many unskilled workers. Gahana, Indonesia, Costra Rica were used to be analyzed in this paper. According to International Water Association data year 2006, those countris earn income per capita less than US$ 9,200 and were categorized as low average – income countries. This research found that minimum wage impelentation in all three countries was not effective. When minimum wage policy was implemented, a lot of people felt aggrieved.</p><p>Keywords : Economic polict, Minimum wage, Income</p>

Breakthrough in hydrolysis of waste biomass by physico-chemical pretreatment processes for efficient anaerobic digestion

Chemosphere ◽  
2022 ◽  
pp. 133617
Author(s):  
Preethi ◽  
Rajesh Banu J ◽  
Sunita Varjani ◽  
Sivashanmugam P ◽  
Vinay Kumar Tyagi ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Waste Biomass ◽  
Chemical Pretreatment ◽  
Physico Chemical ◽  
Hydrolysis Of ◽  
Pretreatment Processes

Advances in benchmarking to improve water utility operations: a review of six IWA books

Water Policy ◽  
2012 ◽  
Vol 15 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Sanford V. Berg
Keyword(s):  
Best Practice ◽  
Water Utility ◽  
Quantitative Studies ◽  
Performance Patterns ◽  
Water Association ◽  
International Water ◽  
Sector Performance ◽  
Historical Developments ◽  
Key Indicators

Six recent publications by the International Water Association underscore the growing importance of quantitative studies of water utilities for identifying (1) performance patterns, (2) trends in key indicators and (3) best practice. Since each author takes a different approach to the problem of performance measurement and incentives for improvement, the books provide different perspectives on the decision-relevance of empirical analysis and cases for managers and policymakers. Key lessons from the volumes include the use of benchmarking as a tool for establishing better internal incentives, the importance of data collection and auditing and the role of transparency in helping stakeholders become more informed about utility operations. Analysts need to help stakeholders understand sector complexities, where hydrology, topology, historical developments outside current management's control, population income levels and the amount of skilled labor differ widely across and even within nations. The six books taken together underscore the value of quantifying relative performance and improving our awareness of production processes and the institutional arrangements that support strong water sector performance.

Good modelling practice in applying computational fluid dynamics for WWTP modelling

2015 ◽  
Vol 73 (5) ◽  
pp. 969-982 ◽  
Author(s):  
Edward Wicklein ◽  
Damien J. Batstone ◽  
Joel Ducoste ◽  
Julien Laurent ◽  
Alonso Griborio ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Working Group ◽  
Companion Paper ◽  
Cfd Modelling ◽  
Cfd Models ◽  
Water Association ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Applications ◽  
International Water

Computational fluid dynamics (CFD) modelling in the wastewater treatment (WWT) field is continuing to grow and be used to solve increasingly complex problems. However, the future of CFD models and their value to the wastewater field are a function of their proper application and knowledge of their limits. As has been established for other types of wastewater modelling (i.e. biokinetic models), it is timely to define a good modelling practice (GMP) for wastewater CFD applications. An International Water Association (IWA) working group has been formed to investigate a variety of issues and challenges related to CFD modelling in water and WWT. This paper summarizes the recommendations for GMP of the IWA working group on CFD. The paper provides an overview of GMP and, though it is written for the wastewater application, is based on general CFD procedures. A forthcoming companion paper to provide specific details on modelling of individual wastewater components forms the next step of the working group.

scholarly journals The IWA Anaerobic Digestion Model No 1 (ADM1)

2002 ◽  
Vol 45 (10) ◽  
pp. 65-73 ◽  
Author(s):  
D.J. Batstone ◽  
J. Keller ◽  
I. Angelidaki ◽  
S.V. Kalyuzhnyi ◽  
S.G. Pavlostathis ◽  
...  
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Ion Association ◽  
Dynamic State ◽  
State Variables ◽  
Physico Chemical ◽  
Chemical Equations ◽  
State Concentration

The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well as physico-chemical processes. The biochemical steps include disintegration from homogeneous particulates to carbohydrates, proteins and lipids; extracellular hydrolysis of these particulate substrates to sugars, amino acids, and long chain fatty acids (LCFA), respectively; acidogenesis from sugars and amino acids to volatile fatty acids (VFAs) and hydrogen; acetogenesis of LCFA and VFAs to acetate; and separate methanogenesis steps from acetate and hydrogen/CO2. The physico-chemical equations describe ion association and dissociation, and gas-liquid transfer. Implemented as a differential and algebraic equation (DAE) set, there are 26 dynamic state concentration variables, and 8 implicit algebraic variables per reactor vessel or element. Implemented as differential equations (DE) only, there are 32 dynamic concentration state variables.

scholarly journals Seasonal Assessment of Water Quality by Statistical Analysis in the Coastal Area of Sindh, Pakistan

2020 ◽  
Vol 63 (2) ◽  
pp. 130-138
Author(s):  
Muhammad Imran Nasir ◽  
Haq Nawaz Abbasi ◽  
Arif Zubair ◽  
Waqar Ahmad
Keyword(s):  
Ionic Composition ◽  
Charge Balance ◽  
Multivariate Statistical ◽  
Data Set ◽  
Coastal Belt ◽  
Physico Chemical ◽  
Groundwater Samples ◽  
Sindh Province ◽  
Geological Formation ◽  
Demographic Patterns

  Monitoring of groundwater is very important because of climatic and demographic patterns along the coastline of Sindh Province, Pakistan. Seventy representative groundwater samples were collected during pre-monsoon and post-monsoon seasons for the investigation of physico-chemical variables to understand the groundwater chemistry of the coastal belt. Multivariate statistical techniques were applied to interpret the data to reveal the pollution sources in the groundwater samples. The normalized charge balance index (NCBI) was computed on the data set and the I:Tz- and I:Tz+ were analyzed in the collected groundwater samples. Cations were in excess and alkalinity in the aquifer of the study area was balanced by Ca+ + Mg+ ions. The contribution of ions was insignificant for charge balance. Mg+2 and Ca+2  were in huge concentration and alkaline hardness was maintained by the alkaline rocks formation. Majority of the charge was balanced by  S0-2 and Cl-. In groundwater ionic composition is used to categorize it into ionic types of groundwater based on the dissolved cation and anion. The ionic reaction is likely regulated by  domestic geological formation. The  sample location illustrates    Na+-S0-2 and Na+-Cl- nature of -2 +- groundwater. The groundwater with  Na+-S04 and Na  -Cl  dominancy generally shows saline characteristics that make groundwater unfit to use for irrigation and drinking purposes.  

Factors Affecting the Incidence of Atrial Fibrillation

1958 ◽  
Vol 193 (2) ◽  
pp. 235-238 ◽  
Author(s):  
W. C. Holland ◽  
Betty Tinsley
Keyword(s):  
Ionic Composition ◽  
Chemical Processes ◽  
Cell Membrane Permeability ◽  
Ion Content ◽  
Factors Affecting ◽  
High Frequencies ◽  
Biochemical Processes ◽  
Physico Chemical ◽  
Transmembrane Flux ◽  
Rabbit Atria

A study of fibrillation induced in isolated rabbit atria by stimulating at high frequencies (600–1200 cycles/min.) in presence of acetylcholine revealed it to be dependent on the ionic composition of the medium. The effects of varying the Na, K and Ca ion content of the bath fluid on the incidence of fibrillation are interrupted on the basis that fibrillation only begins at a time when the transmembrane flux of Na and K ions exceeds a critical rate. Evidence is presented that the initiation and maintenance of fibrillation are governed by separate physico-chemical processes. The onset of fibrillation results from a sudden transient increase in cell membrane permeability. This latter reaction sets off other biochemical processes which maintain the phenomenon.

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