scholarly journals How well can inaccurate sensors quantify and improve the performance of a fleet of on-site wastewater treatment plants?

2021 ◽  
Author(s):  
Mariane Yvonne Schneider ◽  
Hidenori Harada ◽  
Kris Villez ◽  
Max Maurer
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
High Sensitivity ◽  
High Specificity ◽  
True Positive Rate ◽  
Soft Sensors ◽  
True Negative ◽  
Alarm Management ◽  
Treatment Performance ◽  
The Impact

On-site wastewater treatment plants (OSTs) are widely seen as a stopgap solution, mainly because of a lack of monitoring and the resulting unreliable treatment performance. To address this concern, low maintenance, but inaccurate soft sensors are emerging. However, the impact of this inaccuracy on the treatment performance of entire fleets of OSTs has not been quantified. We develop a stochastic model to estimate these performances. In the modelled case soft sensors with a 70% accuracy improve the treatment performance from 66% (percentage of time functional) to 98%. Soft sensors optimised for specificity (true negative rate) improve the system performance, while such optimised for sensitivity (true positive rate) quantify the treatment performance more accurately. Based on this new insight we suggest to build two soft sensors with the same data input in practical settings: one soft sensor geared towards high specificity, for maintenance scheduling, and one geared towards high sensitivity, for fleet performance quantification. The findings suggest that inaccurate sensors in combination with an appropriate alarm management have the potential to largely improve the treatment performance of a fleet of OSTs. We present a management strategy to reduce undetected failures drastically and thereby diminish negative impacts on environmental and human health.

scholarly journals Ecohydrological modelling of water discharge and nitrate loads in a mesoscale lowland catchment, Germany

2009 ◽  
Vol 21 ◽  
pp. 49-55 ◽  
Author(s):  
Q. D. Lam ◽  
B. Schmalz ◽  
N. Fohrer
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Agricultural Land ◽  
Assessment Tool ◽  
Wastewater Treatment Plants ◽  
Water Discharge ◽  
Swat Model ◽  
Validation Period ◽  
Calibration Period ◽  
The Impact

Abstract. The aims of this study are to identify the capacities of applying an ecohydrological model for simulating flow and to assess the impact of point and non-point source pollution on nitrate loads in a complex lowland catchment, which has special hydrological characteristics in comparison with those of other catchments. The study area Kielstau catchment has a size of approximately 50 km2 and is located in the North German lowlands. The water quality is not only influenced by the predominating agricultural land use in the catchment as cropland and pasture, but also by six municipal wastewater treatment plants. Ecohydrological models like the SWAT model (Soil and Water Assessment Tool) are useful tools for simulating nutrient loads in river catchments. Diffuse entries from the agriculture resulting from fertilizers as well as punctual entries from the wastewater treatment plants are implemented in the model set-up. The results of this study show good agreement between simulated and measured daily discharges with a Nash-Sutcliffe efficiency and a correlation coefficient of 0.76 and 0.88 for the calibration period (November 1998 to October 2004); 0.75 and 0.92 for the validation period (November 2004 to December 2007). The model efficiency for daily nitrate loads is 0.64 and 0.5 for the calibration period (June 2005 to May 2007) and the validation period (June 2007 to December 2007), respectively. The study revealed that SWAT performed satisfactorily in simulating daily flow and nitrate loads at the lowland catchment in Northern Germany.

scholarly journals Life Cycle Assessment of Upgrading Primary Wastewater Treatment Plants to Secondary Treatment Including a Circular Economy Approach

2020 ◽  
Vol 13 ◽  
pp. 117862212093585 ◽  
Author(s):  
Karim M Morsy ◽  
Mohamed K Mostafa ◽  
Khaled Z Abdalla ◽  
Mona M Galal
Keyword(s):  
Wastewater Treatment ◽  
Circular Economy ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Scientific Progress ◽  
Primary Treatment ◽  
Secondary Treatment ◽  
Cumulative Impact ◽  
Process Energy ◽  
The Impact

Although significant progress has been achieved in the field of environmental impact assessment in many engineering disciplines, the impact of wastewater treatment plants has not yet been well integrated. In light of this remarkable scientific progress, the outputs of the plants as treated water and clean sludge have become potential sources of irrigation and energy, not a waste. The aim of this study is to assess the environmental impacts of upgrading the wastewater treatment plants from primary to secondary treatment. The Lifecycle Assessment Framework (ISO 14040 and 14044) was applied using GaBi Software. Abu Rawash wastewater treatment plant (WWTP) has been taken as a case study. Two scenarios were studied, Scenario 1 is the current situation of the WWTP using the primary treatment units and Scenario 2 is upgrading the WWTP by adding secondary treatment units. The study highlighted the influence and cumulative impact of upgrading all the primary WWTPs in Egypt to secondary treatment. With the high amount of energy consumed in the aeration process, energy recovery methods were proposed to boost the circular economy concept in Abu Rawash WWTP in order to achieve optimal results from environmental and economic perspectives.

Performance of activated sludge diffusion for biological treatment of hydrogen sulphide gas emissions

2013 ◽  
Vol 68 (9) ◽  
pp. 1932-1939 ◽  
Author(s):  
Vera L. Barbosa ◽  
Richard M. Stuetz
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Hydrogen Sulphide ◽  
Biological Treatment ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Broad Application ◽  
H2s Removal ◽  
Treatment Performance ◽  
Solids Concentration

Odours from wastewater treatment plants are comprised of a mixture of various gases with hydrogen sulphide (H2S) often being the dominant constituent. Activated sludge diffusion (ASD) as a biotreatment system for odour abatement has been conducted for over 30 years but has limited broad application due to disagreement in the literature regarding the effect that ASD may have on wastewater treatment performance. The effects of continuous H2S diffusion at 25 ppmv, with weekly peaks of approximately 100 ppmv, on H2S removal efficiency and wastewater treatment performance was evaluated over a 2-month period using an activated sludge pilot plant. H2S removal averaged 100% during diffusion at 25 ppmv, and 98.9% during the 100 ppmv peak periods. A significant increase in mixed liquor volatile suspended solids concentration (P < 0.01) was observed during H2S diffusion, which may be due to an increase in H2S-degrading microorganisms. There was no adverse effect of H2S on nitrification throughout the ASD trials. Ammonia (NH3) removal was slightly better in the test receiving H2S diffusion (87.6%) than in the control (85.4%). H2S diffusion appeared to improve robustness of the AS biomass to operational upsets.

scholarly journals Rethinking micropollutant removal assessment methods for wastewater treatment plants – how to get more robust data?

2017 ◽  
Vol 75 (12) ◽  
pp. 2964-2972 ◽  
Author(s):  
Jean-Marc Choubert ◽  
Samuel Martin Ruel ◽  
Cécile Miege ◽  
Marina Coquery
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Sampling Strategy ◽  
Sampling Uncertainty ◽  
Limit Of Quantification ◽  
Sources Of Uncertainty ◽  
Micropollutant Removal ◽  
The Impact

This paper covers the pitfalls, recommendations and a new methodology for assessing micropollutant removal efficiencies in wastewater treatment plants. The proposed calculation rules take into account the limit of quantification and the analytical and sampling uncertainty of measured concentrations. We identified six cases for which a removal efficiency value is reliable and four other cases where result is highly variable (uncertain) due to very low or unquantified concentrations in effluent or when the influent–effluent concentrations differential is below the measurement uncertainty. The influence of the proposed calculation rules on removal efficiency values was scrutinized using actual results from a research project. The paper arrives at detailed recommendations for limiting the impact of other sources of uncertainty during sampling (sampling strategy, cleaning and field blank), chemical analyses (suspended solids and sludge) and data processing according to the targeted objectives.

scholarly journals Evaluating the impacts of triclosan on wastewater treatment performance during startup and acclimation

2017 ◽  
Vol 77 (2) ◽  
pp. 493-503 ◽  
Author(s):  
R. M. Holzem ◽  
C. M. Gardner ◽  
C. K. Gunsch
Keyword(s):  
Wastewater Treatment ◽  
Community Diversity ◽  
Synthetic Wastewater ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Sequencing Batch Reactors ◽  
Anaerobic Digesters ◽  
Treatment Performance ◽  
Treatment Facilities ◽  
The Impact

Abstract Triclosan (TCS) is a broad range antimicrobial agent used in many personal care products, which is commonly discharged to wastewater treatment facilities (WWTFs). This study examined the impact of TCS on wastewater treatment performance using laboratory bench-scale sequencing batch reactors (SBRs) coupled with anaerobic digesters. The SBRs were continuously fed synthetic wastewater amended with or without 0.68 μM TCS, with the aim of determining the effect of chronic TCS exposure as opposed to a pulse TCS addition as previously studied. Overall, the present study suggests inhibition of nitrogen removal during reactor startup. However, NH4+ removal fully rebounded after 63 days, suggesting acclimation of the associated microbial communities to TCS. An initial decrease in microbial community diversity was observed in the SBRs fed TCS as compared to the control SBRs, followed by an increase in community diversity, which coincided with the increase in NH4+ removal. Elevated levels of NO3− and NO2− were found in the reactor effluent after day 58, however, suggesting ammonia oxidizing bacteria rebounding more rapidly than nitrogen oxidizing bacteria. Similar effects on treatment efficiencies at actual WWTFs have not been widely observed, suggesting that continuous addition of TCS in their influent may have selected for TCS-resistant nitrogen oxidizing bacteria.

scholarly journals The impact of sludge return liquors on South African wastewater treatment plants

Water SA ◽  
2021 ◽  
Vol 47 (1 January) ◽  
Author(s):  
Olivier Nsengiyumva ◽  
Yuva Coothen ◽  
David Ikumi ◽  
Kirshen Naidoo
Keyword(s):  
Wastewater Treatment ◽  
Steady State ◽  
South African ◽  
Wastewater Treatment Plants ◽  
Full Scale ◽  
Plant Performance ◽  
Model Complexity ◽  
Side Stream ◽  
Struvite Precipitation ◽  
The Impact

There have been three considerable shifts, in the past 20 years, in the conventional design and modelling of wastewater treatment plants (WWTPs): (i) single unit process to plant-wide modelling, (ii) consideration of WWTPs as water and resource recovery facilities (WRRFs), and (iii) the need to simplify WWTP models to allow their intake by new stakeholders (i.e. plant operators, designers and decision-makers) who use these models for evaluation of WWTP optimisation strategies. The latter shift has prompted the debate about model complexity versus the required modelling purpose among modellers. In addition to the aforementioned shifts, there has been limited research on the impact of sludge recycling dewatering liquor on the overall plant performance, especially in the context of South African WWTPs. A simplified full-scale steady-state WWTP simulation tool was developed, based on principles of sound mass-balance stoichiometry and rate-limiting kinetics. This tool enables the user to analyse the impact of recycling the DWL on the plant performance through different scenarios. The strategic scenarios evaluated included the implementation of two side-stream treatment processes (STPs), namely BABE and struvite precipitation. The evaluation of various strategies was done using the benchmark simulation model (BSM) task group plant performance indices (i.e. effluent quality and operational cost indices, EQI and OCI, respectively) incorporated into the simplified steady-state full-scale models. The integration of STP in the WWTP layout results in better EQI and OCI. The composition of the DWL affects the choice of the STP to be used, i.e., for DWL from an AD treating WAS that is not P-rich the recommended side-stream treatment operation would be the BABE process rather than struvite precipitation.

scholarly journals Antimicrobial resistance gene surveillance in the receiving waters of an upgraded wastewater treatment plant

FACETS ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 128-138 ◽  
Author(s):  
Claire N. Freeman ◽  
Lena Scriver ◽  
Kara D. Neudorf ◽  
Lisbeth Truelstrup Hansen ◽  
Rob C. Jamieson ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Antimicrobial Resistance ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Nutrient Content ◽  
Rrna Gene ◽  
Treated Effluent ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
The Impact

Wastewater treatment plants (WWTPs) have been identified as hotspots for antimicrobial resistance genes (ARGs) and thus represent a critical point where patterns in ARG abundances can be monitored prior to their release into the environment. The aim of the current study was to measure the impact of the release of the final treated effluent (FE) on the abundance of ARGs in the receiving water of a recently upgraded WWTP in the Canadian prairies. Sample nutrient content (phosphorous and nitrogen species) was measured as a proxy for WWTP functional performance, and quantitative PCR (qPCR) was used to measure the abundance of eight ARGs, the intI1 gene associated with class I integrons, and the 16S rRNA gene. The genes ermB, sul1, intI1, blaCTX-M, qnrS, and tetO all had higher abundances downstream of the WWTP, consistent with the genes with highest abundance in the FE. These findings are consistent with the increasing evidence suggesting that human activity affects the abundances of ARGs in the environment. Although the degree of risk associated with releasing ARGs into the environment is still unclear, understanding the environmental dimension of this threat will help develop informed management policies to reduce the spread of antibiotic resistance and protect public health.

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