Removal of pathogens from wastewaters by the root zone method (RZM)

1995 ◽  
Vol 32 (3) ◽  
pp. 211-218 ◽  
Author(s):  
Fermin Rivera ◽  
Alan Warren ◽  
Elizabeth Ramirez ◽  
Olivier Decamp ◽  
Patricia Bonilla ◽  
...  
Keyword(s):  
Root Zone ◽  
Climatic Conditions ◽  
Pathogenic Microorganisms ◽  
Faecal Coliforms ◽  
Treatment Efficiency ◽  
Zone Method ◽  
Free Living ◽  
Gravel Beds ◽  
Helminth Eggs ◽  
Better Than

Full-scale and laboratory-scale artificially constructed reed beds utilising the root zone method (RZM) of wastewater treatment were investigated for their removal efficiencies of a range of pathogenic microorganisms. Performances were compared for RZMs employing different hydrophytes, planting substrates and climatic conditions. All pathogens were removed by the RZM to some extent. Planted beds generally performed better than unplanted beds although the type of hydrophyte used was not significant. Gravel beds were more efficient than soil beds in the removal of protozoan pathogens and of helminth eggs; numbers of these pathogens were below levels of detection in gravel bed effluents. For faecal coliforms the type of planting substrate was not significant, providing hydrophytes were present. Climatic conditions made little difference to treatment efficiency although seasonal variation was observed in temperature climates, where the removal of faecal coliforms declined in the winter months, and in subtropical climates where higher numbers of free-living amoebae were recorded during the summer. It was concluded that the RZM is a suitable method for the treatment of domestic wastewaters in tropical and subtropical regions of Mexico.

The application of the root zone method for the treatment and reuse of high-strength abattoir waste in Mexico

1997 ◽  
Vol 35 (5) ◽  
pp. 271-278 ◽  
Author(s):  
Fermin Rivera ◽  
Alan Warren ◽  
Colin R. Curds ◽  
Esperanza Robles ◽  
Alejandro Gutierrez ◽  
...  
Keyword(s):  
Treatment Process ◽  
Root Zone ◽  
Ornamental Plants ◽  
High Strength ◽  
Faecal Coliforms ◽  
Treatment Efficiency ◽  
Zone Method ◽  
Stage System ◽  
Flow Through ◽  
Two Stages

A two-stage system for treating high-strength wastewater from an abattoir at Pachuca, Mexico is described. The system consists of an anaerobic digester followed by an artificially-constructed wetland which employs horizontal subsurface flow through the root zone of emergent hydrophytes planted in a gravel substrate. The main goals of this study were to monitor the treatment efficiency of the system for the first twelve months of operation and to assess the suitability of the effluent for irrigation purposes. The treatment efficiency during the twelve month period was generally good with mean removal efficiencies of 88.5% for BOD5, 87.4% COD, 89% suspended solids, 73.6% organic nitrogen and >99% faecal coliforms. Removal rates were generally poor for orthophosphates, NH3-nitrogen and NO3-nitrogen. The differing roles of the two stages in the treatment process are discussed. Although not suitable for irrigating crops, the effluent is being successfully used for the irrigation of ornamental plants and recreational lands.

The Role of Ciliated Protozoa in Subsurface Flow Wetlands and their Potential as Bioindicators

1999 ◽  
Vol 40 (3) ◽  
pp. 91-98 ◽  
Author(s):  
O. Decamp ◽  
A. Warren ◽  
R. Sanchez
Keyword(s):  
Community Structure ◽  
Root Zone ◽  
Subsurface Flow ◽  
Ciliated Protozoa ◽  
Zone Method ◽  
Gravel Bed ◽  
Gravel Beds ◽  
Ciliate Community ◽  
Unplanted Soil

The role of ciliated protozoa in the root zone method of wastewater treatment was assessed by analyzing ciliate community structure in four experimental subsurface flow wetlands (planted or unplanted in either soil or gravel) and estimating Escherichia coli removal due to ciliate predation. A total of 22 different ciliate taxa were isolated from the four reed beds. The first third of each bed contained a higher abundance and diversity than the final third of the bed. There was a qualitative correlation between physicochemical conditions and ciliate community structure: microaerophilic species dominated the organic-rich and oxygen-poor environment of the unplanted soil bed; aerobic and facultative bacterivorous species dominated the better oxygenated gravel beds; a combination of these two communities was found in the planted soil bed. The average grazing rates of ciliates was around 5 times higher in the planted gravel bed (49 bacteria/ciliate/hour) than in the unplanted soil bed (9.5 bacteria/ciliate/hour). Taking into account the retention time and ciliate abundance, it was calculated that ciliates, by their predatory activities, are capable of removing up to 2.35 × 105 and 0.45 × 105E. coli in the first third of the planted gravel bed and unplanted soil bed, respectively. These results are discussed in relation to variation in E. coli removal kinetics. The potential for using ciliate communities as indicators of conditions within constructed wetlands is also assessed.

An investigation of the pathogenic and non-pathogenic free-living amoebae from the root zone method of wastewater treatment

1993 ◽  
Vol 69 (1-2) ◽  
pp. 93-98 ◽  
Author(s):  
Ferm�n Rivera ◽  
Salvador Rodr�guez ◽  
Alan Warren ◽  
Patricia Bonilla ◽  
Elizabeth Ram�rez ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Root Zone ◽  
Zone Method ◽  
Free Living

The performance of a high-rate algal pond in the Moroccan climate

1995 ◽  
Vol 31 (12) ◽  
pp. 67-74 ◽  
Author(s):  
B. El Hamouri ◽  
J. Jellal ◽  
K. Khallayoune ◽  
A. Benkerroum ◽  
A. Hajli ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Hydraulic Retention Time ◽  
Climatic Conditions ◽  
High Rate ◽  
Biological Processes ◽  
Faecal Coliforms ◽  
First Order ◽  
Helminth Eggs ◽  
Bod Removal

The performance of a wastewater treatment system consisting of an anaerobic pond followed by a high-rate algal pond (HRAP) is presented. The results allowed establishment of a statistical model for HRAP design in similar climatic conditions. The results also allowed the determination of the first-order constant of faecal coliforms (FC) die-off. This constant was found to be 24.7 and 0.97 d-1, respectively, in the hot and the cold seasons. Also, some results are presented on the comprehension of the biological processes which take place in a homogeneous HRAP. They indicate that BOD and FC removals are separated in the time and that BOD removal always precedes FC die-off. Finally the results show that the helminth eggs were completely removed within an overall hydraulic retention time of 8.2 days.

Evaluation of a tropical single-cell waste stabilization pond system for irrigation

1995 ◽  
Vol 31 (12) ◽  
pp. 267-273 ◽  
Author(s):  
B. S. O. Ceballos ◽  
A. Konig ◽  
B. Lomans ◽  
A. B. Athayde ◽  
H. W. Pearson
Keyword(s):  
Single Cell ◽  
Removal Efficiency ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Full Scale ◽  
Waste Stabilization Pond ◽  
North East ◽  
Helminth Eggs ◽  
Waste Stabilization ◽  
Better Than

A single full-scale primary facultative pond in Sapé, north-east Brazil was monitored for performance and efficiency. The pond had a hydraulic retention time of 61 days and achieved a 95% BOD5 removal efficiency and had no helminth eggs in the effluent. The effluent failed to meet the WHO faecal coliform guideline for unrestricted irrigation. The pond was dominated by the cyanobacterium Microcystis and gave better than predicted orthophosphate removal. Details of how the system could be simply upgraded utilizing the same land are discussed.

scholarly journals Effects of Hydrogen Peroxide on Hydroponic Lettuce Grown With Conventional and Organic Fertilizers [Cornell University]

2019 ◽  
Author(s):  
Vanessa M. Lau ◽  
Neil S. Mattson
Keyword(s):  
Hydrogen Peroxide ◽  
Microbial Respiration ◽  
Root Zone ◽  
Organic Fertilizers ◽  
Pathogenic Microorganisms ◽  
Trial And Error ◽  
Dissolved Oxygen Concentration ◽  
Cornell University ◽  
Lactuca Sativa L ◽  
Lettuce Yield

H2O2, commonly referred to as hydrogen peroxide, is an unstable oxidizing agent often used by hydroponic growers to help clear unwanted biofilm and pathogenic microorganisms by releasing free radicals that interact with the microbes. Other byproducts produced by the decomposition of hydrogen peroxide are simply H2O and O2. The released O2 increases the dissolved oxygen concentration in the root zone and may also help reduce oxygen losses to biofilm and microbial respiration. However, the suggested concentration of hydrogen peroxide varies greatly among hobbyists and are typically determined on a trial and error basis and excess H2O2 can cause damage to roots. With little to no scientifically backed information available on the topic, the aim of this study is to determine the effect of H2O2 concentrations in deep water culture hydroponics by assessing how it affects biofilm caused by the use of organic fertilizers, root development, and consequently, yield in lettuce (Lactuca sativa L.) ‘Oak Leaf’. In this experiment, three different treatments consisting of a control, 1.25 mL/L, and 2.5 mL/L of hydrogen peroxide are added to aerated 4-L reservoirs that are fertilized with either organic (4-1-1) or inorganic nutrients (21-5-20), both applied at 150 mg·L-1 N. Three replicates for each treatment and each fertilizer are prepared resulting in a total of eighteen reservoirs with one head of lettuce in each. By the end of this study, it was found that when added to conventional fertilizers, doses of 1.25 mL/L and 2.5 mL/L of hydrogen peroxide stunted the growth of or killed the heads of lettuce.  However, when applied to organic fertilizers, the lettuce yield nearly matched that of the conventionally fertilized control.

scholarly journals Reproductive performance of female swamp buffalo in West Sumatra

2021 ◽  
Vol 748 (1) ◽  
pp. 012025
Author(s):  
R Reswati ◽  
BP Purwanto ◽  
R Priyanto ◽  
W Manalu ◽  
R I Arifiantini
Keyword(s):  
Population Growth ◽  
Reproductive Performance ◽  
Climatic Conditions ◽  
Calving Interval ◽  
Farming Practices ◽  
Age At First Calving ◽  
West Sumatra ◽  
Swamp Buffalo ◽  
Different Altitudes ◽  
Better Than

Abstract The swamp buffalo population in West Sumatra Province decline continuously due to the low female reproductive performance. This research was conducted to identify female buffalo reproductive performance, which could be used as baseline data to enhance its population growth. A survey research method was conducted in two subdistricts, namely Lubuk Basung and Matur, located at different altitudes. Data were collected by interviewing farmers and observing their farms. The parameters observed were age at first mating, age at first calving, calving interval, service per conception, and buffalo farming practices. Significant differences in reproductive performances of female buffalo were observed. Age at first mating 39.04 ± 9.91 and 33.67 ± 5.3 mo., age at first calving 51.61 ± 9.95 and 45.71 ± 5.58 mo., calving interval 27.26 ± 8.84 and 24.17 ± 7.06 mo., and services per conception 1.82 ± 0.82 and 1.55 ± 0.78 were represented buffalo in Lubuk Basung and Matur, respectively. The buffalo reproductive performances in both locations were not optimal; however, Matur’s buffalo reproductive performances were better than those in Lubuk Basung due to its better farming practices and more comfort climatic conditions. Therefore, improving farming practice is essential to enhance buffalo’s reproductive performance and population growth.

The effect of raised beds on soil structure, waterlogging, and productivity on duplex soils in Western Australia

Soil Research ◽  
2005 ◽  
Vol 43 (5) ◽  
pp. 575 ◽  
Author(s):  
D. M. Bakker ◽  
G. J. Hamilton ◽  
D. J. Houlbrooke ◽  
C. Spann
Keyword(s):  
Western Australia ◽  
Soil Structure ◽  
Root Zone ◽  
Infiltration Rate ◽  
Climatic Conditions ◽  
Agricultural Crops ◽  
Yield Increase ◽  
Major Constraint ◽  
No Till ◽  
Poor Soil

Waterlogging and poor soil structure in the root-zone of duplex soils in Western Australia has long been recognised as a major constraint to the production of agricultural crops and pastures. The effect of raised beds on waterlogging, soil structure, and productivity of duplex soils was investigated. Five experimental sites were established, monitored, and operated over 5 years as well as 3 larger scale demonstration sites which were operated over 4 or 3 years. Treatments consisted of raised beds and a normal no-till seed bed as the control. The beds were made with a bed former after the soil had been deep cultivated. Bulk density and steady-state infiltration rate observations indicated significant and lasting improvements in soil structure in the beds. The incidence of waterlogging in raised beds was reduced and this was accompanied by an increase in runoff from the raised beds. The average grain yield increase from the beds was 18% for a variety of crops across a range of climatic conditions and duplex soils. Seven years after the introduction of raised beds for broad-acre farming in Western Australia, more than an estimated 30 000 ha of crops is now grown on raised beds.

Changing sensitivity of global vegetation productivity to hydro-climate drivers

2021 ◽  
Author(s):  
Wantong Li ◽  
Matthias Forkel ◽  
Mirco Migliavacca ◽  
Markus Reichstein ◽  
Sophia Walther ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Root Zone ◽  
Growing Season ◽  
Climatic Conditions ◽  
Terrestrial Vegetation ◽  
Spatial And Temporal Patterns ◽  
Vegetation Productivity ◽  
Area Index ◽  
Global Vegetation

<p>Terrestrial vegetation couples the global water, energy and carbon exchange between the atmosphere and the land surface. Thereby, vegetation productivity is determined by a multitude of energy- and water-related variables. While the emergent sensitivity of productivity to these variables has been inferred from Earth observations, its temporal evolution during the last decades is unclear, as well as potential changes in response to trends in hydro-climatic conditions. In this study, we analyze the changing sensitivity of global vegetation productivity to hydro-climate conditions by using satellite-observed vegetation indices (i.e. NDVI) at the monthly timescale from 1982–2015. Further, we repeat the analysis with simulated leaf area index and gross primary productivity from the TRENDY vegetation models, and contrast the findings with the observation-based results. We train a random forest model to predict anomalies of productivity from a comprehensive set of hydro-meteorological variables (temperature, solar radiation, vapor pressure deficit, surface and root-zone soil moisture and precipitation), and to infer the sensitivity to each of these variables. By training models from temporal independent subsets of the data we detect the evolution of sensitivity across time. Results based on observations show that vegetation sensitivity to energy- and water-related variables has significantly changed in many regions across the globe. In particular we find decreased (increased) sensitivity to temperature in very warm (cold) regions. Thereby, the magnitude of the sensitivity tends to differ between the early and late growing seasons. Likewise, we find changing sensitivity to root-zone soil moisture with increases predominantly in the early growing season and decreases in the late growing season. For better understanding the mechanisms behind the sensitivity changes, we analyse land-cover changes, hydro-climatic trends, and abrupt disturbances (e.g. drought, heatwave events or fires could result in breaking points of sensitivity evolution in the local interpretation). In summary, this study sheds light on how and where vegetation productivity changes its response to the drivers under climate change, which can help to understand possibly resulting changes in spatial and temporal patterns of land carbon uptake.</p>

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