scholarly journals A Mechanistic Model to Assess the Fate of Naphthalene and Benzo(a)pyrene in a Chilean WWTP

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1313
Author(s):  
Antonia Arroyo ◽  
Fabián Provoste ◽  
Montserrat Rodríguez ◽  
Ana L. Prieto

Polycyclic aromatic hydrocarbons (PAHs) are a family of organic compounds of widespread presence in the environment. They are recalcitrant, ubiquitous, prone to bioaccumulation, and potentially carcinogenic. Effluent from wastewater treatment plants (WWTPs) constitutes a major source of PAHs into water bodies, and their presence should be closely monitored, especially considering the increasing applications of potable and non-potable reuse of treated wastewater worldwide. Modeling the fate and distribution of PAHs in WWTPs is a valuable tool to overcome the complexity and cost of monitoring and quantifying PAHs. A mechanistic model was built to evaluate the fate of PAHs in both water and sludge lines of a Chilean WWTP. Naphthalene and benzo(a)pyrene were used as models of low-MW and high-MW PAHs. As there were no reported experimental data available for the case study, the influent load was determined through a statistical approach based on reported values worldwide. For both naphthalene and benzo(a)pyrene, the predominant mechanism in the water line was sorption to sludge, while that in the sludge line was desorption. Compared to other studies in the literature, the model satisfactorily describes the mechanisms involved in the fate and distribution of PAHs in a conventional activated sludge WWTP. Even though there is evidence of the presence of PAHs in urban centers in Chile, local regulatory standards do not consider PAHs in the disposal of WWTP effluents. Monitoring of PAHs in both treated effluents and biosolids is imperative, especially when considering de facto reuse and soil amendment in agricultural activities are currently practiced downstream of the studied WWTP.

2014 ◽  
Vol 33 (4) ◽  
Author(s):  
Henrieta Pavolová ◽  
Adriana Csikósová ◽  
Tomáš Bakalár

AbstractThe development of the regions in Slovakia in recent years has significant disparities in both so-cio-economic as well as environmental issues, as evidenced by the eight environmentally polluted areas (these areas are highly urbanised with industrial agglomerations or intensive agricultural production).This article deals with a management system model of regional by implementation of projects in environmental field of water management with application-specific benefits and risks arising from the process of their implementation in relation to regional development. It analyses projects in the area of water management of one of the regions of Slovakia, KoŠice region in particular, in terms of connection to public water duct and sewer, identifes a strategy for development of the region and its socio-economic and environmental benefits based on the analysis of drinking water, the quan-tity and quality of treated wastewater through wastewater treatment plants (WTPs). It identifes the infuencing factors of benefits and risks and proposes procedure for solving at various stages.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Thuy T. Nguyen ◽  
Paul K. Westerhoff

Abstract De facto potable reuse occurs when treated wastewater is discharged upstream of drinking water treatment plants (DWTPs) and can lead to contaminants of emerging concern (CECs) occurring in potable water. Our prior research, focusing on larger communities that each serve >10,000 people across the USA, indicates that elevated de facto reuse (DFR) occurs in Texas, and thus we added to our model DWTPs serving smaller communities to understand their vulnerability to CECs. Here, we show that two-thirds of all surface water intakes in Texas were impacted by DFR at levels exceeding 90% during even mild droughts, and under average streamflow DFR levels range between 1 and 20%. DWTPs serving lower population communities (<10,000 people) have higher DFR levels, and fewer than 2% of these communities have advanced technologies (e.g., ozone, activated carbon) at DWTPs to remove CECs. Efforts to improve water quality in these less populated communities are an important priority. The model approach and results can be used to identify prioritization for monitoring and treatment of CECs, including in underserved communities, which normally lack knowledge of their impacts from DFR occurring within their watersheds.


2012 ◽  
Vol 65 (7) ◽  
pp. 1179-1189 ◽  
Author(s):  
S. Martin Ruel ◽  
J.-M. Choubert ◽  
H. Budzinski ◽  
C. Miège ◽  
M. Esperanza ◽  
...  

The next challenge of wastewater treatment is to reliably remove micropollutants at the microgram per litre range. During the present work more than 100 substances were analysed through on-site mass balances over 19 municipal wastewater treatment lines. The most relevant substances according to their occurrence in raw wastewater, in treated wastewater and in sludge were identified, and their fate in wastewater treatment processes was assessed. About half of priority substances of WFD were found at concentrations higher than 0.1 μg/L in wastewater. For 26 substances, potential non-compliance with Environmental Quality Standard of Water Framework Directive has been identified in treated wastewater, depending on river flow. Main concerns are for Cd, DEHP, diuron, alkylphenols, and chloroform. Emerging substances of particular concern are by-products, organic chemicals (e.g. triclosan, benzothiazole) and pharmaceuticals (e.g. ketoprofen, diclofenac, sulfamethoxazole, carbamazepine). About 80% of the load of micropollutants was removed by conventional activated sludge plants, but about two-thirds of removed substances were mainly transferred to sludge.


2020 ◽  
Vol 81 (2) ◽  
pp. 217-227
Author(s):  
Khalid Hassan ◽  
Olfat Hamdy ◽  
Mohamed Helmy ◽  
Hossam Mostafa

Abstract This paper documents the results of 12 months of monitoring of an upgraded hybrid moving bed biofilm reactor-conventional activated sludge wastewater treatment plant (MBBR-CAS WWTP). It also targets the assessment of the increment of the hydraulic load on existing treatment units with a zero construction and land cost. The influent flow to the plant was increased from 21,000 m3 d−1 to 30,000 m3 d−1, 40% of the existing CAS reactor volume was used for the MBBR zone with a carrier fill fraction of 47.62% and with Headworks Bio ActiveCell™ 515 used as media; no modifications were made for the primary and secondary tanks. The hybrid reactor showed high removal efficiencies for biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS), with average effluent values recording 33.00 ± 8.87 mg L−1, 52.90 ± 9.65 mg L−1 and 29.50 ± 6.64 mg L−1 respectively. Nutrient removals in the hybrid modified biological reactor were moderate compared with carbon removal despite the high C/N ratio of 12.33. Findings in this study favor the application of MBBR in the upgrading of existing CAS plants with the plant BOD5 removal efficiency recording an increase of about 5% compared with the plant before upgrade and effluent values well within the legal requirements.


2014 ◽  
Vol 71 (2) ◽  
pp. 303-308 ◽  
Author(s):  
D. Mamais ◽  
C. Noutsopoulos ◽  
A. Dimopoulou ◽  
A. Stasinakis ◽  
T. D. Lekkas

The objective of this research was to assess the energy consumption of wastewater treatment plants (WWTPs), to apply a mathematical model to evaluate their carbon footprint, and to propose energy saving strategies that can be implemented to reduce both energy consumption and greenhouse gas (GHG) emissions in Greece. The survey was focused on 10 WWTPs in Greece with a treatment capacity ranging from 10,000 to 4,000,000 population equivalents (PE). Based on the results, annual specific energy consumption ranged from 15 to 86 kWh/PE. The highest energy consumer in all the WWTPs was aeration, accounting for 40–75% of total energy requirements. The annual GHG emissions varied significantly according to the treatment schemes employed and ranged between 61 and 161 kgCO2e/PE. The highest values of CO2 emissions were obtained in extended aeration systems and the lowest in conventional activated sludge systems. Key strategies that the wastewater industry could adopt to mitigate GHG emissions are identified and discussed. A case study is presented to demonstrate potential strategies for energy savings and GHG emission reduction. Given the results, it is postulated that the reduction of dissolved oxygen (DO) set points and sludge retention time can provide significant energy savings and decrease GHG emissions.


2014 ◽  
Vol 5 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. E. Drewes ◽  
S. J. Khan

Water scarcity driven by population growth, lack of conventional supplies, and climate change impacts have resulted in increasing interest worldwide in drinking water augmentation using treated wastewater effluents. Potable reuse can occur indirect or direct, but is also practiced in many places as ‘de facto reuse’, where upstream wastewater discharge occurs to drinking water supplies. With this increasing recognition of potable reuse, there is very limited guidance and standardization for proper design and operation of potable reuse schemes that is protective of public health. This study provided guidance on contemporary approaches for the design, operation, and monitoring of potable reuse schemes, including source water characterization and source control approaches; linking water quality treatment performance goals to health risks; risk mitigation strategies including the design principles of multiple barriers for microbial and chemical contaminants; assessing system reliability and fail-safe design approaches; and, finally, monitoring strategies for process performance and compliance.


Author(s):  
Tolulope Aniyikaiye ◽  
Temilola Oluseyi ◽  
John Odiyo ◽  
Joshua Edokpayi

Effluents from the paint industry have been a major source of environmental pollution. There is a need to investigate the compliance of wastewater discharged from paint industries with regulatory standards. In response, this study evaluates the physicochemical parameters of both raw and treated wastewater, the wastewater treatment plants (WWTPs) efficiencies as well as the compliance level of five selected paint manufacturing companies in Lagos, Nigeria with some regulatory standards: Federal Ministry of Environment (FME) in Nigeria, World Health Organization (WHO) and Department of Water Affairs (DWA) in South Africa. All parameters investigated were analysed using standard methods. The values of pH, electrical conductivity (EC) and total dissolved solids (TDS) levels were in the range of 4–12.2, 149.1–881.3 mS/m and 1100–6510 mg/L, respectively. The range of other parameters include total suspended solids (TSS); 0–2470 mg/L, TS; 1920–6510 mg/L, chloride; 63.8–733.8 mg/L, dissolved oxygen (DO); 0–6.7 mg/L, oil and grease (O & G); 44–100 mg/L, biochemical oxygen demand (BOD); 162.8–974.7 mg/L, chemical oxygen demand (COD); 543–1231 mg/L, nitrates;12.89–211.2 mg/L, phosphate; below detection limit (bdl)–0.02 mg/L, sulphate; 195–1434 mg/L, nickel; bdl–1.9 mg/L while copper, lead and chromium were below detection limits. The results indicated that the WWTPs of the studied paint companies were ineffective in reducing the TS, TSS, BOD, COD and (O & G) to acceptable limits. Routine monitoring of wastewater from paint industries is therefore recommended to prevent the risk of contamination to the receiving watershed which many communities rely on as source for domestic water.


2010 ◽  
Vol 12 (4) ◽  
pp. 380-395 ◽  
Author(s):  
Lorenzo Benedetti ◽  
Webbey De Keyser ◽  
Ingmar Nopens ◽  
Peter A. Vanrolleghem

Process choice and dimensioning of wastewater treatment plants (WWTPs) is difficult while ensuring regulatory standards are met and cost-efficiency is maintained. This step only accounts for a small fraction of the upfront costs, but can lead to substantial savings. This paper illustrates the results of a systematic methodology to evaluate system upgrade options by means of dynamic modelling. In contrast to conventional practice, the presented approach allows the most appropriate trade-off between cost of measures and effluent quality to be chosen and the reliability of a process layout to be assessed by means of uncertainty analysis. In a hypothetical case study, thirteen WWTP upgrade options are compared in terms of their effluent quality and economic performance. A further comparison of two options with regard to the resulting receiving water quality reveals the paramount importance of this aspect, and highlights the inadequacy of evaluation frameworks limited to the performance relative to a sub-system (WWTP effluent) when a wider perspective (as induced by the EU Water Framework Directive) has to be adopted.


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