Biomass development in GAC columns receiving influents with different levels of nutrients

2016 ◽  
Vol 16 (4) ◽  
pp. 1024-1032 ◽  
Author(s):  
Xiaobin Liao ◽  
Rusen Zou ◽  
Chao Chen ◽  
Baoling Yuan ◽  
Zhenming Zhou ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Organic Contaminants ◽  
Oxygen Demand ◽  
Drinking Water Treatment ◽  
Nitrogen Addition ◽  
Ammonia Nitrogen ◽  
Limiting Factor ◽  
Stable Operating ◽  
Biodegradable Dissolved Organic Carbon ◽  
Biofilm Development

Indigenous bacteria are essential for the performance of bio-filters for drinking water treatment. Yet it is slow and difficult to develop biofilm in a granular activated carbon (GAC) filter with low nutritional levels in the influent, especially during winter. In this study, the biofilm development in three laboratory-scale GAC columns with different types of influent was investigated in southeast China during winter. The results indicated that nitrogen was the limiting factor for biofilm development in GAC columns for this source water. The biomass density in the column with ammonia nitrogen addition was much higher than those of the other two filters, while its microbial diversity and biological activity were lower. Moreover, the ammonia-feeding column also showed the highest removal of organic contaminants during the stable operating periods, i.e. chemical oxygen demand (CODMn), assimilable organic carbon as well as biodegradable dissolved organic carbon. Therefore, nitrogen amendment favors the formation of biofilm. It could shorten the start-up time of a GAC filter and enhance the bio-stability of its effluent. This might add some new insights towards the operation of GAC filters with low nutritional levels in the influent during winter.

scholarly journals Effect of corn cobs as external carbon sources on nitrogen removal in constructed wetlands treating micro-polluted river water

2019 ◽  
Vol 79 (9) ◽  
pp. 1639-1647 ◽  
Author(s):  
Lu-ji Yu ◽  
Tao Chen ◽  
Yanhong Xu
Keyword(s):  
Organic Carbon ◽  
River Water ◽  
Constructed Wetlands ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Flow Mode ◽  
Low Carbon ◽  
Polluted River ◽  
Corn Cobs

Abstract Micro-polluted river water is characterized as having limited biodegradability, low carbon to nitrogen ratio and little organic carbon supply, all of which makes it hard to further purify. Two bench scale constructed wetlands (CWs) with a horizontal subsurface flow mode were set up in the laboratory to evaluate their feasibility and efficiency on denitrification with and without corn cobs as external carbon sources. Micro-polluted river water was used as feed solution. The CW without corn cobs substrates possessed a good performance in removing chemical oxygen demand (COD, <40 mg/L) and ammonia nitrogen (NH3-N, <0.65 mg/L), but less efficiency in removing total nitrogen (TN) and nitrate nitrogen (NO3-N). In marked contrast, the CW with 1% (w/w) corn cobs substrates as external carbon sources achieved a significant improvement in the removal efficiency of TN (increased from 34.2% to 71.9%) and NO3-N (increased from 19% to 71.9%). The incorporation of corn cobs substrates did not cause any obvious increase in the concentrations of COD and NH3-N in the effluent. This improvement in the denitrification efficiency was owing to the released organic carbon from corn cobs substrates, which facilitated the growth of abundant microbes on the surface and pores of the substrate. The open area of the used corn chips is larger than that of the pristine ones, and corn cobs can continue to provide a carbon fiber source for denitrification.

Modeling dynamics of organic carbon and nitrogen removal during aeration interruption in aerated horizontal flow treatment wetlands

2019 ◽  
Vol 80 (3) ◽  
pp. 597-606 ◽  
Author(s):  
Johannes Boog ◽  
Thomas Kalbacher ◽  
Jaime Nivala ◽  
Manfred van Afferden ◽  
Roland A. Müller
Keyword(s):  
Steady State ◽  
Organic Carbon ◽  
Dynamic Response ◽  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Treatment Wetlands ◽  
Horizontal Flow ◽  
Simulation Accuracy ◽  
Carbon And Nitrogen

Abstract Despite recent developments in process-based modeling of treatment wetlands (TW), the dynamic response of horizontal flow (HF) aerated wetlands to interruptions of aeration has not yet been modeled. In this study, the dynamic response of organic carbon and nitrogen removal to interruptions of aeration in an HF aerated wetland was investigated using a recently-developed numerical process-based model. Model calibration and validation were achieved using previously obtained data from pilot-scale experiments. Setting initial concentrations for anaerobic bacteria to high values ( 35–70 mg L−1) and including ammonia sorption was important to simulate the treatment performance of the experimental wetland in transition phases when aeration was switched off and on again. Even though steady-state air flow rate impacted steady-state soluble chemical oxygen demand (CODs), ammonia nitrogen (NH4–N) and oxidized nitrogen (NOx–N) concentration length profiles, it did not substantially affect corresponding effluent concentrations during aeration interruption. When comparing simulated with experimental results, it is most likely that extending the model to include mass transfer through the biofilm will allow to better explain the underlying experiments and to increase simulation accuracy. This study provides insights into the dynamic behavior of HF aerated wetlands and discusses assumptions and limitations of the modeling approach.

Identification and prioritization of performancelimiting factors for water treatment plantoptimization in Korea

2006 ◽  
Vol 6 (2) ◽  
pp. 71-76
Author(s):  
N.-S. Park ◽  
J.-H. Kim ◽  
C.-H. Bae ◽  
Y.-T. Moon ◽  
H.-W. Ahn
Keyword(s):  
Water Treatment ◽  
Drinking Water Treatment ◽  
Ammonia Nitrogen ◽  
Limiting Factors ◽  
Limiting Factor ◽  
Manganese Ions ◽  
Injection Point ◽  
Mixing Intensity ◽  
Upward Velocity ◽  
Flocculation Process

Performance limiting factors (PLFs) derived from 161 drinking water treatment plants (DWTPs), assessed by the International Technical Diagnosis and Assistance Center, were analyzed and evaluated in this study. In order to conduct research, 161 DWTPs were divided into five categories depending on their capacity, and into twelve groups according to processes and facilities. From the results of analysis, PLFs and their distribution ratio derived from each category were significantly different. Filtration was the most important performance limiting factor in all DWTPs of five categories, and PLFs in filtration were backwashing velocity, media configuration, bed depth, and formation of mud-ball. The PLFs in coagulation–flocculation process were found to be coagulant dose, mixing intensity, mechanical problems, and others in the order of frequency of occurrence. Also, insufficient disinfection ability, is resulting from insufficient hydraulic detention time, improper chlorine dose and injection point, is the most significant among PLFs in a clear well. In the case of sedimentation, inappropriate baffle structure and excessive upward velocity were PLFs. In addition, the results showed that high turbid water and low alkalinity in rainy season, ferric and manganese ions, and ammonia nitrogen have contributed significantly to the performance of DWTPs.

Hydro-geochemical properties with respect to landuse in the southernmost river of Kerala

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Badusha M. ◽  
Santhosh S
Keyword(s):  
Organic Carbon ◽  
Drainage Basin ◽  
Anthropogenic Activities ◽  
Oxygen Demand ◽  
Ion Concentration ◽  
Total Hardness ◽  
Hydrogen Ion Concentration ◽  
Geochemical Properties ◽  
Quality Of Water

The hydro geochemical features of Neyyar River for a period of one year from May 2015 to April 2016 were analyzed. Six sampling sites were fixed considering physiography and present landuse pattern of the river basin. The residents in the drainage basin are primarily responsible for framing a better landuse and thereby maintain a good water and sediment regime. Geospatial pattern of the present landuse of the study area indicated that the sustainability of this river ecosystem is in danger due to unscientific landuse practices, which is reflected in the river quality as well. The parameters such as hydrogen ion concentration, electrical conductivity, chloride, Biological Oxygen Demand, total hardness and sulphate of river water and Organic Carbon of river bed sediments were analyzed in this study. The overall analysis shows that the highland areas are characterized by better quality of water together with low organic carbon, which is mainly due to better landuse and minimal reclamation. The midland and lowland areas are characterized by poor quality of water with high organic carbon, which is due to high anthropogenic activities and maximum pollutants associated with the region together with the alteration in landuse from a traditional eco-friendly pattern to a severely polluted current pattern.

Improving the biological stability of drinking water by ion exchange

2011 ◽  
Vol 11 (1) ◽  
pp. 107-112 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
S. A. Baghoth ◽  
E. R. Cornelissen ◽  
L. C. Rietveld
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Ion Exchange ◽  
Biofilm Formation ◽  
Formation Rate ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Biological Stability ◽  
Biological Activated Carbon ◽  
Pre Treatment

To guarantee a good water quality at the consumer’s tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research is to measure the effect of NOM removal by ion exchange on the biological stability of drinking water. Experiments were performed in two lanes of the pilot plant of Weesperkarspel in the Netherlands. The lanes consisted of ozonation, softening, biological activated carbon filtration and slow sand filtration. Ion exchange in fluidized form was used as pre-treatment in one lane and removed 50% of the dissolved organic carbon (DOC); the other lane was used as reference. Compared to the reference lane, the assimilable organic carbon (AOC) concentration of the finished water in the lane pretreated by ion exchange was 61% lower. The biofilm formation rate of the finished water was decreased with 70% to 2.0 pg ATP/cm2.day. The achieved concentration of AOC and the values of the biofilm formation rate with ion exchange pre-treatment showed that the biological stability of drinking water can be improved by extending a treatment plant with ion exchange, especially when ozonation is involved as disinfection and oxidation step.

scholarly journals Spatiotemporal Effects and Driving Factors of Water Pollutants Discharge in Beijing–Tianjin–Hebei Region

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1174
Author(s):  
Qilong Ren ◽  
Hui Li
Keyword(s):  
Economic Development ◽  
Industrial Structure ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Pollutant Emissions ◽  
Spatial Correlations ◽  
Time Data ◽  
Spatiotemporal Evolution ◽  
Water Pollutants ◽  
Pollutant Discharge

The problem of water pollution is a social issue in China requiring immediate and urgent solutions. In the Beijing–Tianjin–Hebei region, the contradiction between preserving the ecological environment and facilitating sustainable economic development is particularly acute. This study analyzed the spatiotemporal evolution of water pollutants and their factors of influence using statistics on the discharge of two water pollutants, namely chemical oxygen demand (COD) and NH3-N (ammonia nitrogen), in 154 counties in both 2012 and 2016 as research units in the region. The study employed Exploratory Spatial-Time Data Analysis (ESTDA), Standard Deviational Ellipse (SDE), and the Geographically Weighted Regression (GWR) models, as well as ArcGIS and GeoDa software, obtaining the following conclusions: (1) From 2012 to 2016, pollutant discharge dropped significantly, with COD and NH3-N emissions decreasing 65.9% and 47.2%, respectively; the pollutant emissions possessed the spatial feature of gradual gradient descent from the central districts to the periphery. (2) The water pollutants discharge displayed significant and positive spatial correlations. The spatiotemporal cohesion of the spatiotemporal evolution of the pollutants was higher than their spatiotemporal fluidity, representing strong spatial locking. (3) The level of economic development, the level of urbanization, and the intensity of agricultural production input significantly and positively drove pollutant discharge; the environmental regulations had a significant effect on reducing the emission of pollutants. In particular, the effect for NH3-N emissions reduction was stronger; the driving effect of the industrial structure and the distance decay was not significant.

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