scholarly journals Characteristics and performance of small and medium wastewater treatment plants in Greece

2017 ◽  
Vol 12 (3) ◽  
pp. 520-533
Author(s):  
E. Gavalakis ◽  
P. Poulou ◽  
A. Tzimas
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Waste Water Treatment ◽  
Organic Load ◽  
Wastewater Management ◽  
Effluent Quality ◽  
Future Challenges ◽  
And Performance

Wastewater management in Greece is being regulated by the Urban Waste Water Treatment Directive (UWWTD) and as a result many wastewater treatment plants (WWTPs) have been constructed during the last 30 years and are in operation. The present work aims to outline the progress regarding the implementation of the specific environmental policy, present deficiencies and future challenges, while an evaluation of the performance is conducted for small-medium and large WWTPs focusing on the influent and effluent quality characteristics. In Greece the existing level of treatment provided is related to secondary treatment for the removal of organic load, which in most cases is supplemented by nitrogen removal (for more than 85% of the WWTPs) and phosphorus removal. With respect to the characteristics of the raw municipal wastewater these correspond to typical low to medium strength sewage. Compliance to the UWWTD effluent standards for BOD5, COD and SS is achieved in more than 90% of the WWTPs, while in terms of nutrients, 80% of the WWTPs efficiently remove nitrogen and approximately 45% of the WWTPs remove phosphorus.

scholarly journals The control of small and medium sized public wastewater treatment plants in the Veneto region (North Italy): general situation, critical issues and case studies

2017 ◽  
Vol 12 (4) ◽  
pp. 761-779
Author(s):  
M. Ostoich ◽  
F. Serena ◽  
A. Pozzobon ◽  
L. Tomiato
Keyword(s):  
Wastewater Treatment ◽  
Case Studies ◽  
Wastewater Treatment Plants ◽  
Waste Water Treatment ◽  
River Basin Management ◽  
Critical Parameters ◽  
Organic Load ◽  
General Situation ◽  
Veneto Region ◽  
Critical Issues

Abstract Water bodies' quality objectives are defined in accordance with the Urban Wastewater Treatment Directive 91/271/EEC and the Water Framework Directive 2000/60/EC. For regulation and control of small-sized waste-water treatment plants (WWTPs), responsibility is delegated in Italy to Regional Authorities that fix specific regulations (Water Protection Plan WPP included in the River Basin Management Plan RBMP) in collaboration with the District Authorities. Small (<2,000 population equivalent – PE) and medium sized (2,000–10,000 PE) WWTPs in the Veneto Region (North Italy) represent about 10% of the total organic load (Imhoff systems included). This also comprises some industrial discharges. Due to the urban sprawl, plants are spread over the regional territory. In the Veneto Region, data from the official census reveals there are n. 248 plants under 2,000 PE and 135 plants in 2,000–10,000 range while the total number of authorized plants is 488 for a total potentiality of 9,141,572 PE. Data from institutional controls performed by the Veneto Regional Environmental Agency (ARPAV) on WWTPs has been recovered for all the WWTPs with up to 10,000 PE in the provinces of Venice, Treviso and Vicenza (for a total of 306,118 PE and for a total of 164 plants) in the period 2008–2015 and elaborated to assess critical parameters and plants. The general situation, critical issues and case studies have been presented and discussed. Organic load, nutrients and Escherichia coli are the most critical parameters considering the regional WPP.

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.

Performance of a combined eco-system of ponds and constructed wetlands for wastewater reclamation and reuse

2005 ◽  
Vol 51 (12) ◽  
pp. 315-323 ◽  
Author(s):  
L. Wang ◽  
J. Peng ◽  
B. Wang ◽  
R. Cao
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
National Standards ◽  
Municipal Wastewater Treatment ◽  
Wastewater Reclamation ◽  
Effluent Quality ◽  
Major Mechanism ◽  
Removal Efficiencies ◽  
Municipal Wastewater Treatment Plants

An on-site study on the operational performance of a combined eco-system of ponds and SF constructed wetland for municipal wastewater treatment and reclamation/reuse in Donging City, Shandong, China was carried out from January 2001 through October 2003. The removal efficiencies for various main parameters were: TSS 84.8±7.3%, BOD5 87.2±5.3%, CODCr 70.2±18.6%, TP 52.3±23.1%, and NH3-N 54.8±23.9% with effluent concentration of TSS 9.12±5.12 mg/l, BOD5 6.44±4.58 mg/l, CODCr 42.8±6.7 mg/l, TP 0.94±0.27 mg/l and NH3-N 7.95±2.36 mg/l. In addition, the removal efficiencies for faecal coliforms and total bacteria were >99.97% and >99.998% respectively, which well meet Chinese National standards for effluent quality of municipal wastewater treatment plants. The composition of TSS was closely related to CODCr and BOD5 variations, and nitrification-denitrification is the major mechanism of nitrogen removal both in ponds and in wetlands. In addition, sedimentation also played an important role in the removal of TSS, nitrogen, phosphorus and BOD5. The removal efficiencies of various parameters, the number of species and biomass of biological community in the system increased gradually with the ecological maturation.

Nitrogen removal by recycle water nitritation as an attractive alternative for retrofit technologies in municipal wastewater treatment plants

2004 ◽  
Vol 49 (5-6) ◽  
pp. 39-46 ◽  
Author(s):  
K.-I. Gil ◽  
E. Choi
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biological Nutrient Removal ◽  
Recycle Water ◽  
Municipal Wastewater Treatment ◽  
Effluent Quality ◽  
Municipal Wastewater Treatment Plants ◽  
Final Effluent

The recycle water from sludge processing in municipal wastewater treatment plants causes many serious problems in the efficiency and stability of the mainstream process. Thus, the design approach for recycle water is an important part of any biological nutrient removal system design when a retrofit technology is required for upgrading an existing plant. Moreover, the application of nitrogen removal from recycle water using the nitritation process has recently increased due to economic reasons associated with an effective carbon allocation as well as the minimization of aeration costs. However, for the actual application of recycle water nitritation, it has not been fully examined whether or not additional volume would be required in an existing plant. In this paper, the addition of recycle water nitritation to an existing plant was evaluated based on a volume analysis and estimation of final effluent quality. It was expected that using the reserve volume of the aeration tank in existing plants, recycle water nitritation could be applied to a plant without any enlargement. With the addition of recycle water nitritation, it was estimated that the final effluent quality would be improved and stabilized, especially in the winter season.

scholarly journals Cost of Urban Wastewater Treatment and Ecotaxes: Evidence from Municipalities in Southern Europe

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 423 ◽  
Author(s):  
Encarnación Moral Pajares ◽  
Leticia Gallego Valero ◽  
Isabel Román Sánchez
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Methodological Approach ◽  
Economic Feasibility ◽  
Wastewater Management ◽  
Management Service ◽  
Southern Europe ◽  
Urban Wastewater ◽  
Urban Wastewater Treatment

The principle of cost recovery established by the Water Framework Directive underlines the need for tax rates, which can raise enough revenue to finance the cost of treatments applied to wastewater. The objective of this research is to gain an understanding the different types of charges related to urban wastewater treatment that can be levied by the authorities responsible for this service. This paper also aims to determine whether these taxes contribute to guaranteeing the economic feasibility of the wastewater treatment plants. The proposed methodological approach is applied to 18 municipalities of a province in southern Europe in 2017. The results confirm that in most of these cases, the taxes levied do not guarantee adequate tax revenues to cover the running, maintenance and investment costs of municipal wastewater treatment plants. This situation leads to a lack of financial self-sufficiency in the wastewater management service, meaning that the imbalance between income and expenditure has to be covered by government subsidies. The results of this study will help guide authorities around the world that are in charge of managing urban wastewater treatment services.

Upgrading of Small Municipal Wastewater Treatment Plants with Heavy Dairy Loading by Introduction of Aerated Submerged Biological Filters

1990 ◽  
Vol 22 (7-8) ◽  
pp. 191-198 ◽  
Author(s):  
Hallvard Ødegaard ◽  
Bjørn Rusten
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Combined Treatment ◽  
Organic Load ◽  
Municipal Wastewater Treatment ◽  
Biological Filter ◽  
Municipal Wastewater Treatment Plants ◽  
Insufficient Knowledge ◽  
Biological Filters

Most of the dairies in Norway discharge their wastewater to the municipal sewers. Insufficient knowledge about the organic load coming from the dairies, has resulted in inadequate design and organic overloading in the municipal wastewater treatment plants of this category. Several of the plants that originally based their biological process upon RBC as the bioprocess, have experienced mechanical breakdown of the RBC system. The submerged biological filter (SABF) has been introduced as an alternative biofilm method that may be used when broken down RBC-plants (or activated sludge plants) are to be upgraded. The paper describes results from pilot-plant experiments on dairy waste when the SABF is used for pretreatment, as well as results from plants in practice where the SABF is used for combined treatment of the dairy and municipal wastewater. It is shown how pretreatment in a balancing tank may be established, and results from the use of an alternative floating biofilm media are given.

Microsieving in primary treatment: effect of chemical dosing

2016 ◽  
Vol 74 (2) ◽  
pp. 438-447 ◽  
Author(s):  
J. Väänänen ◽  
M. Cimbritz ◽  
J. la Cour Jansen
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Primary Treatment ◽  
Municipal Wastewater Treatment ◽  
Chemically Enhanced Primary Treatment ◽  
Municipal Wastewater Treatment Plants

Primary and chemically enhanced primary wastewater treatment with microsieving (disc or drum filtration) was studied at the large pilot scale at seven municipal wastewater treatment plants in Europe. Without chemical dosing, the reduction of suspended solids (SS) was (on average) 50% (20–65%). By introducing chemically enhanced primary treatment and dosing with cationic polymer only, SS removal could be controlled and increased to >80%. A maximum SS removal of >90% was achieved with a chemical dosing of >0.007 mg polymer/mg influent SS and 20 mg Al3+/L or 30 mg Fe3+/L. When comparing sieve pore sizes of 30–40 μm with 100 μm, the effluent SS was comparable, indicating that the larger sieve pore size could be used due to the higher loading capacity for the solids. Phosphorus removal was adjusted with the coagulant dose, and a removal of 95–97% was achieved. Moreover, microsieving offers favourable conditions for automated dosing control due to the low retention time in the filter.

Steel slag filters to upgrade phosphorus removal in small wastewater treatment plants: Removal mechanisms and performance

2014 ◽  
Vol 68 ◽  
pp. 214-222 ◽  
Author(s):  
Cristian Barca ◽  
Daniel Meyer ◽  
Martin Liira ◽  
Peter Drissen ◽  
Yves Comeau ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Wastewater Treatment Plants ◽  
Steel Slag ◽  
Removal Mechanisms ◽  
And Performance
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