scholarly journals Solar disinfection and lime stabilization processes for reduction of pathogenic bacteria in sewage effluents and biosolids for agricultural purposes in Yemen

2015 ◽  
Vol 5 (3) ◽  
pp. 419-429 ◽  
Author(s):  
Adel A. S. Al-Gheethi ◽  
Norli Ismail ◽  
A. N. Efaq ◽  
J. D. Bala ◽  
Ramzy M. A. Al-Amery
Keyword(s):  
Pathogenic Bacteria ◽  
Middle Eastern ◽  
Sewage Treatment ◽  
Lime Treatment ◽  
Advanced Country ◽  
Climate Conditions ◽  
Safety Control ◽  
Solar Disinfection ◽  
Effluent Quality ◽  
Sewage Effluents

Yemen is the least advanced country among Middle Eastern countries in sewage reuse and safety control. The current sewage effluent quality in Yemen is generally poor as none of the existing sewage treatment plants produces effluents that comply with the effluent quality regulations. There is no plan to build tertiary treatment systems. However, the oxidation and stabilization ponds are considered most appropriate for the warm climate conditions in the country. Sewage effluents and biosolids generated from these ponds are used extensively for agricultural purposes. This review discusses the potential use of solar disinfection (SODIS) and lime treatment for the reduction of pathogens in sewage effluents and biosolids before reuse. SODIS and lime treatment are natural processes, simple, easily implemented, produce non-toxic by-products and are low cost. The merits of these processes are enormous, and they are suitable for application in developing countries such as Yemen.

scholarly journals Dynamics of the behaviour of a vertical wetland (French system) operating in warm-climate conditions, evaluated by means of variables continuously measured in situ

2020 ◽  
Vol 82 (5) ◽  
pp. 954-966
Author(s):  
Mirene A. de Andrade Moraes ◽  
Jorge A. García Zumalacarregui ◽  
Camila Maria Trein ◽  
Marcos von Sperling
Keyword(s):  
Sewage Treatment ◽  
Continuous Variables ◽  
Close Link ◽  
Climate Conditions ◽  
Effluent Quality ◽  
Hydraulic Behaviour ◽  
Feeding Cycle ◽  
System Operating ◽  
Aeration Capacity

Abstract The sewage treatment system in this study was operated with only the first stage of a French system of vertical wetlands, composed of two units in parallel and running with an extended feeding cycle (7 days). This research sought to evaluate and relate continuous variables measured in situ (dissolved oxygen (DO), pH and redox potential) throughout the feeding cycle, with measurements at distinct heights along the filter vertical profile. Additionally, the influence of the surface organic sludge deposit was investigated. A close link between the hydraulic behaviour and the effluent quality was verified, with both being related to the batch volume and the instantaneous hydraulic loading rate. The drop in DO as the feed days progressed could be related to the loss of hydraulic conductivity. A thicker sludge layer decreased the aeration capacity of the filter. The effluent was observed to be aerated when percolating through the medium. DO and pH data suggested that nitrification varied along the filter depth, the batch duration and the feed cycle. The monitored parameters may be indicative of the behaviour of other parameters.

Distribution of Enteric Viruses and Microorganisms in Long-Term Sewage-Treated Soil

1983 ◽  
Vol 15 (5) ◽  
pp. 129-135 ◽  
Author(s):  
Z Filip ◽  
K Seidel ◽  
H Dizer
Keyword(s):  
Soil Bacteria ◽  
Pathogenic Bacteria ◽  
Sewage Treatment ◽  
Anaerobic Bacteria ◽  
Enteric Viruses ◽  
Sewage Irrigation ◽  
Groundwater Samples ◽  
West Berlin ◽  
Aerobic Soil

To determine whether long-term sewage treatment can take place without a pollution risk for soil and groundwater, samples from sewage irrigation fields in West Berlin which have been in use since about 1890 were analyzed for enteric viruses and microorganisms. Enteric viruses were detected in only seven samples from a total number of eighty seven taken from different soil depths. With only one exception, no viruses were found below 60 cm. No viruses were detected in groundwater samples. Long-term sewage irrigation did not result in significant changes in the colony courts of aerobic soil bacteria, but the counts of anaerobic bacteria and actinomycetes were slightly elevated and those of microscopic fungi slightly decreased. Potentially pathogenic bacteria were not detected in soil below 90 cm.

Sewage Treatment in Helophyte Beds–First Experiences with a New Treatment Procedure

1987 ◽  
Vol 19 (10) ◽  
pp. 1-10 ◽  
Author(s):  
K. Bucksteeg
Keyword(s):  
Waste Water ◽  
Rural Areas ◽  
Root Zone ◽  
Waste Water Treatment ◽  
Sewage Treatment ◽  
Uptake Capacity ◽  
Humid Climate ◽  
Climate Conditions ◽  
Trickling Filters ◽  
Operation Conditions

Waste water treatment in helophyte beds under humid climate conditions has been favoured by some German ecologists for some years. The idea is to cause waste water to flow horizontally through the root zone of helophytes to achieve satisfactory effluent properties. There exist many highly different proposals regarding the choice of soil and helophytes to be applied, bed area, design of inlets and outlets and operation conditions. A few plants have been operated in practice for some years. It appears that clogging is one of the main problems occurring in these plants. The hydraulic uptake capacity of soil is discussed in Darcy's law. Comparisons with observations of plants in operation are drawn. The interactions between soil properties, its uptake capacity, BOD5-, COD-, N- and P-reduction are evaluated. The effluent results of helophyte beds are compared with those of low-loaded trickling filters and of ponds used for sewage treatment in small villages in rural areas of Germany. It has been proved that the total construction costs of sewage treatment plants with helophyte beds used as the biological stage are higher when compared with those of conventional plants in general.

Danish Experience with Emergent Hydrophyte Treatment Systems (EHTS) and Prospects in the Light of Future Requirements on Outlet Water Quality

1990 ◽  
Vol 22 (3-4) ◽  
pp. 65-72 ◽  
Author(s):  
H.-H. Schierup ◽  
H. Brix
Keyword(s):  
Wastewater Treatment ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Reed Beds ◽  
Effluent Quality ◽  
Multi Stage ◽  
Run Off ◽  
Stage System

Since 1983 approximately 150 full-scale emergent hydrophyte based wastewater treatment plants (reed beds) have been constructed in Denmark to serve small wastewater producers. The development of purification performance for 21 plants representing different soil types, vegetation, and hydraulic loading rates has been recorded. Cleaning efficiencies were typically in the range of 60-80% reduction for BOD, 25-50% reduction for total nitrogen, and 20-40% reduction for total phosphorus. The mean effluent BOD, total nitrogen and total phosphorus concentrations of the reed beds were 19 ± 10, 22 ± 9 and 6.7 ± 3.2 mg/l (mean ± SD), respectively. Thus, the general Danish effluent standards of 8 mg/l for N and 1.5 mg/l for P for sewage plants greater than 5,000 PE cannot be met by the present realised design of EHTS. The main problem observed in most systems is a poor development of horizontal hydraulic conductivity in the soil which results in surface run-off. Since the political demands for effluent quality will be more strict in the future, it is important to improve the performance of small decentral sewage treatment plants. On the basis of experiences from different types of macrophyte based and conventional low-technology wastewater treatment systems, a multi-stage system is suggested, consisting of sedimentation and sand filtration facilities followed by basins planted with emergent and submergent species of macrophytes and algal ponds.

scholarly journals Bacteria from the Genus Arcobacter Are Abundant in Effluent from Wastewater Treatment Plants

2020 ◽  
Vol 86 (9) ◽  
Author(s):  
Jannie Munk Kristensen ◽  
Marta Nierychlo ◽  
Mads Albertsen ◽  
Per Halkjær Nielsen
Keyword(s):  
Wastewater Treatment ◽  
Pathogenic Bacteria ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Amplicon Sequencing ◽  
Rrna Gene ◽  
Content Type ◽  
Effluent Quality ◽  
Culture Independent ◽  
Influent Wastewater

ABSTRACT Pathogenic bacteria in wastewater are generally considered to be efficiently removed in biological wastewater treatment plants. This understanding is almost solely based on culture-based control measures, and here we show, by applying culture-independent methods, that the removal of species in the genus Arcobacter was less effective than for many other abundant genera in the influent wastewater. Arcobacter was one of the most abundant genera in influent wastewater at 14 municipal wastewater treatment plants and was also abundant in the “clean” effluent from all the plants, reaching up to 30% of all bacteria as analyzed by 16S rRNA gene amplicon sequencing. Metagenomic analyses, culturing, genome sequencing of Arcobacter isolates, and visualization by fluorescent in situ hybridization (FISH) confirmed the presence of the human-pathogenic Arcobacter cryaerophilus and A. butzleri in both influent and effluent. The main reason for the high relative abundance in the effluent was probably that Arcobacter cells, compared to those of other abundant genera in the influent, did not flocculate and attach well to the activated sludge flocs, leaving a relatively large fraction dispersed in the water phase. The study shows there is an urgent need for new standardized culture-independent measurements of pathogens in effluent wastewaters, e.g., amplicon sequencing, and an investigation of the problem on a global scale to quantify the risk for humans and livestock. IMPORTANCE The genus Arcobacter was unexpectedly abundant in the effluent from 14 Danish wastewater treatment plants treating municipal wastewater, and the species included the human-pathogenic A. cryaerophilus and A. butzleri. Recent studies have shown that Arcobacter is common in wastewater worldwide, so the study indicates that discharge of members of the genus Arcobacter may be a global problem, and further studies are needed to quantify the risk and potentially minimize the discharge. The study also shows that culture-based analyses are insufficient for proper effluent quality control, and new standardized culture-independent measurements of effluent quality encompassing most pathogens should be considered.

Relationships between bacteria and cyanobacteria in the Marrakech waste stabilisation ponds

2000 ◽  
Vol 42 (10-11) ◽  
pp. 171-178 ◽  
Author(s):  
K. Oufdou ◽  
N. Mezrioui ◽  
B. Oudra ◽  
M. Barakate ◽  
M. Loudiki ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Mediterranean Climate ◽  
Treatment Process ◽  
Heterotrophic Bacteria ◽  
Sewage Treatment ◽  
Ecological Effect ◽  
E Coli ◽  
Waste Stabilisation Ponds ◽  
Cyanobacteria Blooms ◽  
Synechocystis Sp

In waste stabilisation pond systems the interactions between algae and bacteria have an important ecological effect and appeared to play a key role in the self-purification process. The aim of the present study is to evaluate the interactions between two axenic cyanobacteria: Synechocystis sp. and Pseudanabaena sp. with heterotrophic bacteria and some pathogenic bacteria: E. coli, Salmonella sp. and non-O1 V. cholerae. The results obtained showed that Synechocystis sp. (planktonic cyanobacterium) and Pseudanabaena sp. (benthic cyanobacterium) stimulated the growth and the survival of heterotrophic bacteria and non-O1 V. cholerae and reduced the survival of E. coli and Salmonella. Blooms of these cyanobacteria during hot periods which are a particularity in stabilisation ponds of Marrakech, could explain the dynamics of bacteria studied in this sewage treatment process. The presence of heterotrophic bacteria, showing relative high densities during hot periods, could be considered as an important bioticfactor which led to the cyanobacteria blooms in the Marrakech ponds which function under an arid Mediterranean climate.

Alternative Approaches for Upgrading Effluent Quality for Lagoon Based Systems

1993 ◽  
Vol 28 (10) ◽  
pp. 201-205
Author(s):  
Brian Evans ◽  
Stephen Nutt ◽  
Tony Ho ◽  
Henryk Melcer
Keyword(s):  
Suspended Solids ◽  
Total Population ◽  
Sewage Treatment ◽  
Effluent Quality ◽  
Waste Sludge ◽  
Clean Environment ◽  
Alternative Approaches ◽  
The Cost ◽  
Phosphorus Levels ◽  
Lagoon Systems

The province of Ontario is Canada's most populous province with over 8 million residents out of a total population of 27 million. The province has 512 sewage treatment plants of which 137 or 27% are lagoons. Improved environmental effluent quality standards since the introduction of the lagoons has resulted in many of these being unable to achieve proper effluent quality. Typical effluent quality requirements across the province require a minimum of secondary treatment, that is 15 mg/l of BOD and suspended solids and 1 mg/l of total phosphorus. The movement towards a clean environment has resulted in phosphorus levels as low as 0.3 mg/l TP and in an increasing number of cases, full nitrification year round. Because many of these lagoons serve small populations in the 100 - 3 000 population equivalents category, the cost of upgrading such lagoons to tertiary quality effluent is significant. Two approaches for upgrading conventional lagoon systems were evaluated. They are called the Sutton and New Hamburg processes after the towns in Ontario where they were first installed. The Sutton process consists of extended aeration plant, followed by polishing lagoons with waste sludge sent directly to the lagoons, while the New Hamburg process consists of conventional lagoons followed by intermittent sand filtration.

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