scholarly journals Mineralization of organic matter and productivity of tifton 85 grass (Cynodon spp.) in soil incorporated with stabilized sludge from a vertical flow constructed wetland

2019 ◽  
Vol 9 (2) ◽  
pp. 309-318
Author(s):  
Diogo André P. Silva ◽  
Antonio T. Matos ◽  
Mateus P. Matos
Keyword(s):  
Organic Matter ◽  
Kinetic Equations ◽  
Global Network ◽  
Septic Tank ◽  
Vertical Flow ◽  
Two Phase ◽  
Mineralization Of Organic Matter ◽  
Total Ammonia ◽  
Generous Support ◽  
Different Depths

Abstract Little is known regarding how to discard the sludge accumulated in vertical flow constructed wetlands (VF-CWs) and what the potential impacts could be. The objective of this paper was to evaluate the mineralization of organic matter (OM) in soil and productivity of tifton 85 grass (Cynodon spp.) after incorporating sludge collected at different depths from a VF-CW (used to treat septic tank sludge), to a tropical soil (Oxisol). Sludge samples were collected at depths of 0–5, 5–10 and 10–15 cm from a VF-CW that was used over a period of three years. The sludge collected at each depth was incorporated into the soil at a dose equivalent to 30 g m–2 year–1 of total nitrogen, and the experimental area was planted. During a period of 215 days, total and easily oxidizable carbon, total, ammonia, nitric and organic nitrogen in the residue-soil mixtures were analyzed. Based on the data obtained, the mineralization fractions (MF) were estimated for the specific monitoring period and annually considering first order and two-phase kinetic equations. The annual MF of the OM were higher than 96% and the sludge-amended soil resulted in an increase in grass yield. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

Experiences with a top layer of gravel to enhance the performance of vertical flow constructed wetlands at cold temperatures

2009 ◽  
Vol 59 (6) ◽  
pp. 1111-1116 ◽  
Author(s):  
Guenter Langergraber ◽  
Alexander Pressl ◽  
Klaus Leroch ◽  
Roland Rohrhofer ◽  
Raimund Haberl
Keyword(s):  
Organic Matter ◽  
Constructed Wetlands ◽  
Common Reed ◽  
Treated Wastewater ◽  
Second Phase ◽  
Vertical Flow ◽  
Cold Temperatures ◽  
Main Layer ◽  
Gravel Layer ◽  
Filter Bed

In a first phase of this study it was shown that the Austrian effluent standards for organic matter could not be met in winter for vertical flow (VF) beds designed for and loaded with 27 g COD.m−2.d−1 (3 m2 per person equivalent). The aim of this second phase of the study was to investigate, if the performance of a constructed wetland can be enhanced, i.e. if the effluent requirements can be met, when an additional gravel layer (15 cm, 4–8 mm) is added on top of the main layer of the VF bed. The hypothesis was that this top layer would increase the thermal insulation and consequently the temperatures in the filter bed during cold periods, thus resulting in higher removal efficiencies during winter. Two VF beds were operated in parallel; one bed with such a 15 cm top layer, one without. Otherwise the construction of both beds was identical: surface area of about 20 m2, 50 cm main layer (grain size 0.06–4 mm, d10=0.2 mm; d60=0.8 mm), planted with common reed (Phragmites australis). The beds were intermittently loaded 4 times per day with mechanically pre-treated wastewater (hydraulic loading: 47 mm.d−1; median value of the influent concentration: 505 mg COD.L−1). Despite a better performance during the first winter, the bed with additional top layer showed in general a very unstable performance. It is assumed that the main reason for this was that the oxygen transfer was reduced by the additional top layer so far that suspended organic matter could not any longer be degraded in between loadings. Therefore clogging of the filter occurred.

Quantifying hydrophobicity of natural organic matter using partition coefficients in aqueous two-phase systems

Chemosphere ◽  
2019 ◽  
Vol 218 ◽  
pp. 922-929 ◽  
Author(s):  
Heyun Fu ◽  
Kun Liu ◽  
Pedro J.J. Alvarez ◽  
Daqiang Yin ◽  
Xiaolei Qu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Partition Coefficients ◽  
Two Phase ◽  
Aqueous Two Phase Systems ◽  
Phase Systems

Mineralization of organic matter and the carbon sequestration capacity of zonal soils

2008 ◽  
Vol 41 (7) ◽  
pp. 717-730 ◽  
Author(s):  
V. M. Semenov ◽  
L. A. Ivannikova ◽  
T. V. Kuznetsova ◽  
N. A. Semenova ◽  
A. S. Tulina
Keyword(s):  
Organic Matter ◽  
Carbon Sequestration ◽  
Mineralization Of Organic Matter ◽  
Zonal Soils

scholarly journals Turbidity reduction in drinking water by coagulation-flocculation with chitosan polymers

2019 ◽  
Vol 17 (2) ◽  
pp. 204-218 ◽  
Author(s):  
Ampai Soros ◽  
James E. Amburgey ◽  
Christine E. Stauber ◽  
Mark D. Sobsey ◽  
Lisa M. Casanova
Keyword(s):  
Drinking Water ◽  
Functional Groups ◽  
Dose Range ◽  
Optimal Dose ◽  
Global Network ◽  
Point Of Zero Charge ◽  
Household Water ◽  
Generous Support ◽  
Higher Doses ◽  
Model Household

Abstract Turbidity reduction by coagulation-flocculation in drinking water reduces microbes and organic matter, increasing effectiveness of downstream treatment. Chitosan is a promising household water coagulant, but needs parameters for use. This study tested the effects of chitosan dose, molecular weight (MW), degree of deacetylation (DD), and functional groups on bentonite and kaolinite turbidity reduction in model household drinking water. Higher MW or DD produced greater reductions. Highest reductions were at doses 1 and 3 mg/L by MW >50,000 or >70% DD (residual turbidity <5 NTU). Higher doses did not necessarily continually increase reduction. For functional groups, 3 mg/L produced the highest reductions by lactate, acetate, and HCl, and lower reductions of kaolinite than bentonite. Doses where the point of zero charge was observed clustered around 3 mg/L. Chitosan reduced clay turbidity in water; effectiveness was influenced by dose, clay type, MW, DD, and functional groups. Reduction did not necessarily increase with MW. Bentonite had a broader effective dose range and higher reduction at the optimal dose than kaolinite. Chitosans with and without functional groups performed similarly. The best of the studied doses was 3 mg/L. Chitosans are promising for turbidity reduction in low-resource settings if combined with sedimentation and/or filtration. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

scholarly journals The pursuit of good microbiological conditions in domestic softeners: a new improvement

2020 ◽  
Vol 18 (2) ◽  
pp. 200-206
Author(s):  
L. Bolelli ◽  
Elida Nora Ferri ◽  
Stefano Sangiorgi ◽  
Giuseppe Novelli ◽  
Stefano Girotti
Keyword(s):  
Pathogenic Bacteria ◽  
Microbiological Quality ◽  
Global Network ◽  
Plate Count ◽  
Bacteria Growth ◽  
Warm Environment ◽  
Quality Of Water ◽  
Softened Water ◽  
Generous Support

Abstract Effective resin disinfection is mandatory to ensure the microbiological quality of water treated by domestic softeners. The wet and sometimes warm environment inside the softener is ideal for bacteria growth. Our research was focused on the evaluation of the microbial quality of water from softeners sanitized by chlorine solutions or by electrolytic systems. We employed the heterotrophic plate count and specific tests to monitor the presence of opportunistic and pathogenic bacteria (Pseudomonas aeruginosa, Escherichia coli, enterococci, and coliforms). Completely new devices were equipped with a commercially available electrolytic system or with a newly patented one or sanitized by automatic or manual addition of chlorine solutions. In all cases, the contamination was reduced, not completely avoided. In particular, the patented electrolytic system significantly reduced bacterial proliferation in strongly contaminated devices. Our data confirm the difficulties encountered to solve the problem of microbiological quality of softened water and offer encouraging information on new possible solutions. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

scholarly journals Does the source of water for piped supplies affect child health? Evidence from rural Vanuatu

2019 ◽  
Vol 9 (3) ◽  
pp. 591-595
Author(s):  
Tim Foster ◽  
Emily Rand ◽  
Erie Sami ◽  
Brieana Dance ◽  
Jeremy Kohlitz ◽  
...  
Keyword(s):  
Water Supply ◽  
Water Source ◽  
Service Level ◽  
Water Systems ◽  
Global Network ◽  
Water Supply Systems ◽  
Piped Water ◽  
Generous Support ◽  
Year 2000 ◽  
Supply Systems

Abstract Piped water systems are considered to provide the highest service level for drinking water supplies; however, global monitoring of safe water access pays little attention to the type of water source that piped systems draw upon, even if the water is not treated prior to distribution. This study sought to understand whether the source of water for untreated piped supplies influences the prevalence of diarrhoea among children in rural Vanuatu. The analysis was based on a dataset integrating a Demographic and Health Survey and a nationwide water supply inventory. After adjusting for a range of potential confounders, the results revealed a significant association between diarrhoea and the type of water source supplying a piped system. Compared with borehole-supplied piped systems, spring-fed piped systems were significantly associated with increased odds of diarrhoea (adjusted odds ratio [AOR] 5.8, 95% confidence interval [CI] 1.1–31, p = 0.040). No significant association between diarrhoea and piped systems drawing on surface water was observed. Increased odds of diarrhoea were significantly associated with water supply systems constructed prior to the year 2000 (AOR 4.9, 95% CI 1.9–13, p = 0.001). The results highlight the need for improvements in spring protection as well as ongoing maintenance and periodic renewal of water supply infrastructure. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

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