scholarly journals Sustainability of decentralized wastewater treatment technologies

2017 ◽  
Vol 12 (2) ◽  
pp. 463-477 ◽  
Author(s):  
A. G. Capodaglio ◽  
A. Callegari ◽  
D. Cecconet ◽  
D. Molognoni
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Water Cycle ◽  
Biological Membrane ◽  
New Technology ◽  
Small Communities ◽  
Load Variations ◽  
Hydraulic Load ◽  
Local Water ◽  
Centralized Wastewater Treatment

In many Countries, small communities are required to treat wastewater discharges to increasing standards of lesser environmental impacts, but must achieve that goal at locally sustainable costs. While biological membrane treatment (membrane bio-reactors (MBRs)) is quickly becoming the industry standard for centralized wastewater treatment plants, and would also be ideally suited also for small plants potentially subject to relatively large hydraulic load variations, its investment and operating costs are usually high for that class of applications. Consequently, small treatment plants are generally configured as anoxic or aerated biological tanks with little sedimentation, making them quite susceptible to hydraulic loads transient and sludge quality changes. As an alternative, Constructed Wetlands Systems (CWSs) are gradually and successfully being introduced in many Countries. CWSs are designed to utilise the natural functions of wetland vegetation, soils and their microbiological populations to treat wastewater. Pretreatment occurs by filtration and settling, followed by bacterial decomposition in a natural-looking lined marsh. A new technology, a new type of membrane-like aerobic reactor initially designed for the degradation of hydrocarbon-derived groundwater contaminants, was recently tested for treating domestic, with performance similar to that of MBRs. Examples from the above applications are illustrated and compared in this paper. The paper also discusses merits and drawbacks of the various illustrated technologies, in view of their sustainability potential, and according to the new development paradigms for urban water systems, that encourage the development of local water-cycle clusters with local reuse and recycle of the resource, and possible local recovery of energy and/or materials.

Clustering of towns and villages for centralized wastewater treatment

1995 ◽  
Vol 32 (11) ◽  
pp. 85-95 ◽  
Author(s):  
Hassaan A. Abd El Gawad ◽  
J. H. C. Butter
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Point Of View ◽  
Wastewater Management ◽  
Specific Situation ◽  
Master Plan ◽  
Operation Costs ◽  
Treatment Technologies ◽  
Centralized Wastewater Treatment ◽  
Number Of Treatment

In 1993 the Governorate of Fayoum completed its master plan for wastewater management. The master plan presents a staged implementation schedule for the development of wastewater facilities for the Governorate, covering needs up to the year 2020. The targets are ambitious: in order to meet sanitary health standards, nearly two million people (or 60% of the total population) living in 70 towns and villages would need to be served with sewerage systems. Providing all these areas with separate wastewater treatment plants would be impractical. The centralization of treatment at a limited number of treatment plants for clusters of towns and villages has advantages in terms of manageability, cost and environmental protection. In the master plan the configuration of these clusters is presented. For that purpose a stepped approach has been developed: an approach in which aspects such as construction and operation costs of the facilities, existing infrastructure, the geography of the governorate, environmental impact, alternative treatment technologies and phasing of implementation have been considered. An important element of the stepped approach is an analytical model with which - from financial point of view - the optimum size of a cluster can be estimated. Variables of the model are sizes of towns and villages, distances and treatment technologies. The output of the model is a set of general design criteria which has been applied to the specific situation in the governorate. The model has contributed to the establishment of the Master Plan for Wastewater: a plan now used by the Fayoum Sanitation Department as a framework to initiate new projects and to direct the activities of other agencies working in the sanitation sector in the governorate.

scholarly journals Investigating the impacts of extraneous water on wastewater treatment plants

2016 ◽  
Vol 75 (4) ◽  
pp. 847-855 ◽  
Author(s):  
S. Rödel ◽  
F. W. Günthert ◽  
T. Brüggemann
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Wastewater Treatment Plants ◽  
Measurement Data ◽  
Practical Investigations ◽  
Organic Load ◽  
Sewer Pipes ◽  
Purification Efficiency ◽  
Theoretical Approaches ◽  
Local Water

To demonstrate the effects of increased extraneous water on operation, purification, and energy efficiency, two wastewater treatment plants (WWTPs) have been investigated in detail under the research project ‘Sealing of sewer pipes – Effects on the purification performance of WWTPs and their impact on the local water balance’. Both treatment plants, after evaluating and analyzing the measurement data and information about them, were compared in the light of existing literature and other practical investigations. Furthermore, the results were assessed with respect to transferability to other treatment plants. In WWTP 1, extraneous water reduction led to lower energy consumption of certain plant components such as the pumping station and aeration. An increased percentage of extraneous water had an impact on the wastewater characteristics (e.g. organic load) in WWTP 2. A decrease in extraneous water increases the concentration of biodegradable matters; however, an increase in extraneous water increases the loads in the effluent. The results are in accordance with the theoretical approaches described in the literature and confirm the correlations between extraneous water and purification efficiency and energy consumption of WWTPs.

Increased performance of secondary clarifiers using dynamic distribution of minimum return sludge rates

2009 ◽  
Vol 60 (9) ◽  
pp. 2439-2445 ◽  
Author(s):  
A. Lynggaard-Jensen ◽  
P. Andreasen ◽  
F. Husum ◽  
M. Nygaard ◽  
J. Kaltoft ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Suspended Solids ◽  
Considerable Increase ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Total Flow ◽  
Equal Distribution ◽  
Solids Concentration ◽  
Hydraulic Load ◽  
And Control

Most wastewater treatment plants have several secondary clarifiers or even more sets of clarifiers including several secondary clarifiers, and in practice it is a well known problem that equal distribution of the load to the single clarifier (or set of clarifiers) is very difficult—not to say impossible—to obtain. If the problem is neglected, quite a big percentage of the total clarifier capacity—measured as the max. allowed hydraulic load—can be lost. Further, return sludge rates are seldom controlled by any other means than as a (typically too high) percentage of the inlet to the wastewater treatment plant—giving a varying and too low suspended solids concentration in the return sludge, which again can lead to an unnecessary use of polymer in the pre-dewatering of the surplus sludge taken from the return sludge. A control of the return sludge rate divided into two parts - control of the total return sludge flow and control of how the total flow shall be distributed between the secondary clarifiers - is able to solve the mentioned problems. Finally, as shall be demonstrated on full scale wastewater treatment plants, a considerable increase of the hydraulic capacity of the treatment plants can be obtained.

Modelling of the Secondary Clarifier Combined with the Activated Sludge Model No. 1

1992 ◽  
Vol 25 (6) ◽  
pp. 285-300 ◽  
Author(s):  
René Dupont ◽  
Mogens Henze
Keyword(s):  
Wastewater Treatment ◽  
Simple Model ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Activated Sludge Model ◽  
Effluent Quality ◽  
Secondary Clarifier ◽  
Hydraulic Load ◽  
Flux Model

Modelling of activated sludge wastewater treatment plants is today generally based on the Activated Sludge Model No. 1 combined with a very simple model for the secondary settler. This paper describes the development of a model for the secondary clarifier based on the general flux theory for zone settling, which can be used in combination with the Activated Sludge Model to form a dynamic computer model/program for a wastewater treatment plant. In addition to the flux model, the developed model includes a simple model for predicting the contents of paniculate components in the effluent This latter model is a purely empirical model, which connects the effluent quality with the hydraulic load, suspended solids load and the nitrate load. The paper describes the model and gives some basic examples on computer simulations and verification of the model.

scholarly journals Performance and reliability comparison of French vertical flow treatment wetlands with other decentralized wastewater treatment technologies in tropical climates

2020 ◽  
Vol 82 (8) ◽  
pp. 1701-1709
Author(s):  
Rémi Lombard-Latune ◽  
Florent Leriquier ◽  
Chafatayne Oucacha ◽  
Lucas Pelus ◽  
Gérald Lacombe ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Wetlands ◽  
Vertical Flow ◽  
Small Communities ◽  
Decentralized Wastewater Treatment ◽  
Treatment Technologies ◽  
Rotating Biological Contactors ◽  
Overseas Territories ◽  
Flow Treatment

Abstract When implementing a sanitation system, the selection of treatment process can be difficult. Beyond removal efficiency and effluent concentrations, reliability should be taken into account. This study compares reliability of French vertical flow treatment wetlands (F-VFTW) with the four main decentralized wastewater treatment technologies in small communities in the French Overseas Territories (FOT). Analysis of 963 regulatory self-monitoring sampling campaigns performed on 213 wastewater treatment plants show that operational disruptions due to sludge loss and loss of nitrification are often reported for activated sludge technology; rotating biological contactors often suffer from weak settlement; facultative pond removal is limited by algae; and F-VFTW fulfills all the French regulatory objectives at a frequency of 90 to 95%. In addition, the data from this study are compared to a similar database from Brazil using a statistical approach (coefficient of reliability). Amongst the eight decentralized wastewater treatment technologies evaluated, F-VFTW appears to be the most appropriate for achieving the discharge standard with a reliability close to 95%. Its reliability to face both environmental (rainfall) and social (maintenance capacities) constraints is a key parameter.

scholarly journals Role of different wastewater treatment plants in antibiotic resistance spreading

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
S Bonetta ◽  
C Pignata ◽  
S a Bonetta ◽  
E Gasparro ◽  
E Lorenzi ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Wastewater Treatment ◽  
Antimicrobial Resistance ◽  
One Health ◽  
Wastewater Treatment Plants ◽  
Water Cycle ◽  
Action Plan ◽  
Urban Water ◽  
Urban Water Cycle

Abstract The global action plan on antimicrobial resistance reports the necessity to develop standards and guidance for the presence of antimicrobial agents in the environment, especially in wastewater, highlighting its possible role in the antibiotic resistance spreading. In addition, the New European One Health Action Plan against Antimicrobial Resistance underlines the need to support research into knowledge gaps on the release of resistant microorganisms into the environment and their dissemination. The aim of this study was to evaluate the presence of Antibiotic Resistance Bacteria (ARB) and Antibiotic Resistance Genes (ARG) in wastewater treatment plants (WWTPs). At this scope, untreated sewage and treated effluents of three different WWTPs (A, B and C) were sampled for one year. Sample dilutions were plated on R2Agar added/not-added with 4 different antibiotics (ampicillin 32mg/L; tetracycline 16 mg/L; chloramphenicol 32 mg/L; sulfamethoxazole 50,4 mg/L) to evaluate the percentage of antibiotic resistant bacteria and their WWTPs removal rate (%). DNA extraction on the filter used to concentrate the wastewater samples was performed to reveal the ARG presence; subsequently specific PCRs for ARG (blaTEM, tetA, sul II, sul III) were carried out. ARB were detected in all samples analysed. The highest antibiotic resistance percentage was revealed in the sewage (mean 21,7%±4,8) and effluent (mean 21,1%±3,0) of the three wastewater treatment plants for sulfamethoxazole. Moreover, sul II was the most present gene in the samples (81% of all samples, 89 % of sewages and 72% of effluents). The lower WWTPs removal was recovered in the plant B for the tetracycline (95, 7%). The results obtained underlines the need to monitor WWTP as critical hot spot for the antibiotic resistance spreading also considering the One Health approach. Furthermore, the results obtained could suggest interventions to reduce the spread of the antibiotic resistance in the integrated urban water cycle. Key messages The information obtained could provide usefulness information about the role of wastewater treatment plant in the antibiotic resistance spreading. The results could contribute to suggest the interventions targeted to reduce the antibiotic resistance phenomenon in the integrated urban water cycle.

Small wastewater treatment plants in mountain areas: combination of septic tank and biological filter

2007 ◽  
Vol 56 (10) ◽  
pp. 65-71 ◽  
Author(s):  
S. Maunoir ◽  
H. Philip ◽  
A. Rambaud
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Research Work ◽  
Septic Tank ◽  
Mountain Areas ◽  
Small Communities ◽  
Treatment Processes ◽  
New Process ◽  
The Alps ◽  
The University

Research work has been carried out for more than 20 years by Eparco and the University of Montpellier (France) on the application of biological wastewater treatment processes for small communities. This research has led to a new process which is particularly suitable for remote populations, taking into account several specificities such as as the seasonal fluctuations in the population, the accessibility of the site, the absence of a power supply on site, the reduced area of land available and the low maintenance. Thus, the process, which combines a septic tank operating under anaerobic conditions and a biological aerobic filter, is a solution for wastewater treatment in mountain areas. This paper presents the process and three full-scale applications in the region of the Alps.

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