scholarly journals Influences of rainfall variables and antecedent discharge on urban effluent concentrations and loads in wet weather

2017 ◽  
Vol 75 (7) ◽  
pp. 1584-1598 ◽  
Author(s):  
Zuxin Xu ◽  
Lijun Xiong ◽  
Huaizheng Li ◽  
Zhengliang Liao ◽  
Hailong Yin ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Regression Equations ◽  
Event Mean Concentration ◽  
Pollutant Concentrations ◽  
Receiving Waters ◽  
Discharge Volume ◽  
Wet Weather ◽  
Rain Events ◽  
Major Factors ◽  
Mean Concentration

For storm drainages inappropriately connected with sewage, wet weather discharge is a major factor that adversely affects receiving waters. A study of the wet weather influences of rainfall-discharge variables on storm drainages connected with sewage was conducted in the downtown Shanghai area (374 ha). Two indicators, event mean concentration (EMC) and event pollutant load per unit area (EPL), were used to describe the pollution discharge during 20 rain events. The study showed that the total rainfall and discharge volume were important factors that affect the EMCs and EPLs of the chemical oxygen demand, total phosphorus, and especially those of NH4+-N. The pollutant concentrations at the beginning of the discharge and the discharge period were also major factors that influence the EMCs of these three pollutants. Regression relationships between the rainfall-discharge variables and discharge volume/ EPLs (R2 = 0.824–0.981) were stronger than the relationships between the rainfall-discharge variables and EMCs. These regression equations can be considered reliable in the system, with a relative validation error of less than ±10% for the discharge volume, and less than ±20% for the EPLs. The results presented in this paper provide guidance for effectively controlling pollution in similar storm drainages.

Diffuse pollution monitoring and modelling of small urban watershed in Brazil Cerrado

2019 ◽  
Vol 79 (10) ◽  
pp. 1912-1921 ◽  
Author(s):  
T. M. Tsuji ◽  
M. E. L. Costa ◽  
S. Koide
Keyword(s):  
Oxygen Demand ◽  
Diffuse Pollution ◽  
Pollution Monitoring ◽  
Urban Watershed ◽  
Event Mean Concentration ◽  
Urban Catchment ◽  
Storm Water Management Model ◽  
Receiving Waters ◽  
Mean Concentration

Abstract The stormwater runoff carries different pollutants that can reduce the quality of receiving waters due to diffuse pollutant loads. This research was aimed at evaluating the concentration of pollutants in stormwater and the application of SWMM (Storm Water Management Model) to an urban catchment in Lake Paranoá watershed to carry out the simulation of flow discharge with the hydraulic model, and subsequently to estimate the loads conveyed to the lake in ordinary events of precipitation. This study was carried out based on rainfall and runoff monitoring during events. It was confirmed that this model's results fit well in simulation of this type of watershed, leading to high value of the Nash–Sutcliffe coefficient after calibration but, as expected, precipitation distribution is a very important factor for calibration. Concerning water quality, it was observed that the event mean concentration values of suspended solids and chemical oxygen demand were high, indicating that the diffuse pollution is an important source of pollution of the receiving waters. The monitoring and modelling of stormwater are essential to identify diffuse pollution discharge, in searching for a sustainable solution.

scholarly journals Determination of NPS Pollutant Unit Loads from Different Landuses

2021 ◽  
Vol 13 (13) ◽  
pp. 7193
Author(s):  
Jiyeon Choi ◽  
Baekyung Park ◽  
Jinsun Kim ◽  
Soyoung Lee ◽  
Jichul Ryu ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Oxygen Demand ◽  
Runoff Coefficient ◽  
Forest Land ◽  
Event Mean Concentration ◽  
Rainfall Events ◽  
Total Phosphorous ◽  
Mean Concentration

This study aimed to estimate pollutant unit loads for different landuses and pollutants that reflected long-term runoff characteristics of nonpoint source (NPS) pollutants and recent environmental changes. During 2008–2014, 2026 rainfall events were monitored. The average values of antecedent dry days, total rainfall, rainfall intensity, rainfall duration, runoff duration, and runoff coefficient for each landuse were 3.8–5.9 d, 35.2–65.0 mm, 2.9–4.1 mm/h, 12.5–20.4 h, 12.4–27.9 h, and 0.24–0.45, respectively. Uplands (UL) exhibited high suspended solids (SS, 606.2 mg/L), total nitrogen (TN, 7.38 mg/L), and total phosphorous (TP, 2.27 mg/L) levels, whereas the runoff coefficient was high in the building sites (BS), with a high impervious surface ratio. The event mean concentration (EMC) for biological oxygen demand (BOD) was the highest in BS (8.0 mg/L), while the EMC was the highest in BS (in the rainfall range <10 mm) and UL and forest land (in the rainfall range >50 mm). The unit loads for BOD (1.49–17.76 kg/km2·d), TN (1.462–10.147 kg/km2·d), TP (0.094–1.435 kg/km2·d), and SS (15.20–327.70 kg/km2·d) were calculated. The findings can be used to manage NPS pollutants and watershed environments and implement relevant associated management systems.

scholarly journals Continuous Monitoring of Turbidity and Conductivity in Wastewater Networks

2015 ◽  
Vol 28 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Thomas Bersinger ◽  
Isabelle Le Hécho ◽  
Gilles Bareille ◽  
Thierry Pigot ◽  
Alexandre Lecomte
Keyword(s):  
Total Nitrogen ◽  
Continuous Monitoring ◽  
Oxygen Demand ◽  
Rain Event ◽  
Aquatic Life ◽  
Pollutant Concentrations ◽  
Rain Events ◽  
The One ◽  
Continuous Estimation ◽  
The Impact

Continuous monitoring of the sanitation network of the urban catchment of Pau (southwest France) has been performed since March 2012 using rain gauges, flowmeters, as well as turbidity and conductivity probes. Good correlations were obtained between turbidity, total suspended solids (TSS) and chemical oxygen demand (COD) on the one hand, and conductivity and total nitrogen on the other hand. This allowed an instantaneous and continuous estimation of pollutant concentrations and fluxes since that date. In the present paper we focused on the results of October 2012, which was characterized by alternating periods of dry and rainy events. Turbidity and conductivity raw data show different trends during the study period depending on the parameter and the rain events. A turbidity peak is observed at the beginning of each rain event but its amplitude varies with the intensity of the rain and the length of the preceding dry weather period. Conversely, conductivity decrease during each rain event implying, that rain water acts as a dilution factor. The behaviour of COD and total nitrogen differ markedly due to their partitioning between the dissolved (total nitrogen) and particulate phases (COD). Daily pollutant fluxes allow a global comprehension and monitoring of the sewer system. Important COD fluxes during a rain event preceded by a long dry weather period highlight the importance of erosion of sedimentary deposits in the sewerage network. During these events, important fluxes are discharged into receiving water leading to the question of the impact on aquatic life. Generally, these results highlight the potential of online monitoring to better understand the behaviour of the sewer network on long or short time scales. This could be a useful tool to manage wastewater treatment.

Accuracy of different sensors for the estimation of pollutant concentrations (total suspended solids, total and dissolved chemical oxygen demand) in wastewater and stormwater

2013 ◽  
Vol 68 (2) ◽  
pp. 462-471 ◽  
Author(s):  
Mathieu Lepot ◽  
Jean-Baptiste Aubin ◽  
Jean-Luc Bertrand-Krajewski
Keyword(s):  
Chemical Oxygen Demand ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Detection Methods ◽  
Time Step ◽  
Pollutant Concentrations ◽  
Uv Visible ◽  
Wet Weather

Many field investigations have used continuous sensors (turbidimeters and/or ultraviolet (UV)-visible spectrophotometers) to estimate with a short time step pollutant concentrations in sewer systems. Few, if any, publications compare the performance of various sensors for the same set of samples. Different surrogate sensors (turbidity sensors, UV-visible spectrophotometer, pH meter, conductivity meter and microwave sensor) were tested to link concentrations of total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), and sensors' outputs. In the combined sewer at the inlet of a wastewater treatment plant, 94 samples were collected during dry weather, 44 samples were collected during wet weather, and 165 samples were collected under both dry and wet weather conditions. From these samples, triplicate standard laboratory analyses were performed and corresponding sensors outputs were recorded. Two outlier detection methods were developed, based, respectively, on the Mahalanobis and Euclidean distances. Several hundred regression models were tested, and the best ones (according to the root mean square error criterion) are presented in order of decreasing performance. No sensor appears as the best one for all three investigated pollutants.

Pollution based real time control of wastewater systems

2002 ◽  
Vol 45 (3) ◽  
pp. 219-228 ◽  
Author(s):  
L.P. Risholt ◽  
W. Schilling ◽  
V. Erbe ◽  
J. Alex
Keyword(s):  
Real Time ◽  
Chemical Precipitation ◽  
Actual State ◽  
Real Time Control ◽  
Design Load ◽  
Time Control ◽  
Pollutant Concentrations ◽  
Wastewater Systems ◽  
Receiving Waters ◽  
Wet Weather

Wastewater systems are traditionally built as static systems to handle a design load. The real load varies, though, and hardly ever equals the design load. This implies that wastewater systems hardly ever operate in an optimum way, especially during wet weather. Real time control (RTC) of regulators can improve the operation by better fit of the system to the actual state and load. RTC based on pollutant concentrations together with hydraulic conditions (pollution based real time control, PBRTC) is investigated in this paper to assess the potential pollutant load reduction on receiving waters at wet weather without expansion of transport or storage capacity. Both CSOs and WWTP effluents contribute to the pollutant discharges to receiving waters and both are considered. Three cases are studied to assess the potential benefit of PBRTC. Giving priority to the most polluted wastewater for treatment and storage in branched interceptor systems can reduce CSO discharge loads by more than 20%. Biological WWTPs and especially activated sludge plants are more complex and less stable than chemical precipitation plants during and after high pollutant and hydraulic load. Biological plants can hence profit more from PBRTC than chemical precipitation plants. Receiving waters that are sensitive to acute effects caused by intermittent discharges can benefit more from PBRTC than receiving waters with problems connected to long-term accumulation of pollution.

Hydrological and environmental assessment of urban growth in a sub-tropical town in India

2014 ◽  
Vol 70 (11) ◽  
pp. 1721-1728 ◽  
Author(s):  
Himanshu Joshi ◽  
Abdul Hameed M. Jawad Al Obaidy
Keyword(s):  
Urban Soil ◽  
Pollution Index ◽  
Regression Equations ◽  
Event Mean Concentration ◽  
Total Load ◽  
Metal Pollution Index ◽  
Study Sites ◽  
Storm Characteristics ◽  
Different Sources ◽  
Mean Concentration

Roorkee, a sub-tropical urban town in India, has shown a rapid unplanned growth in the past. This paper presents the findings of a study of characteristics of urban soil, rainwater, and runoff emanating from different sources areas and the stormwater flows in the drains. Urban soil showed significant increase in the concentration of all constituents in comparison to the nearby rural soil. Soil metal pollution index suggested multi-element contamination. The traffic and transportation system emerged as the major source of metals and organics. Concentration of rainwater ions was observed to follow the pattern Ca2+ &gt; HCO3− &gt; Cl− &gt; NO3− &gt; Na+ &gt; Mg2+ &gt; SO42− &gt; K+. Runoff results indicated a significant enhancement in the concentration of most measured constituents over their rainfall levels. The values of runoff coefficient varied between 0.05 and 0.58, with the high values displayed by the paved areas. Multiple regression equations were developed relating event mean concentration to various storm characteristics. The total load of all measured constituents was observed to vary considerably among the study sites, the direct runoff loads being much higher than the dry weather loads.

Sensitivity to experimental data of pollutant site mean concentration in stormwater runoff

2005 ◽  
Vol 51 (2) ◽  
pp. 155-162 ◽  
Author(s):  
M. Mourad ◽  
J.-L. Bertrand-Krajewski ◽  
G. Chebbo
Keyword(s):  
Experimental Data ◽  
Mean Value ◽  
Weighted Mean ◽  
Pollutant Loads ◽  
Total Runoff ◽  
Receiving Waters ◽  
Wet Weather ◽  
A Site ◽  
Mean Concentration

Urban wet weather discharges are known to be a great source of pollutants for receiving waters, which protection requires the estimation of long-term discharged pollutant loads. Pollutant loads can be estimated by multiplying a site mean concentration (SMC) by the total runoff volume during a given period of time. The estimation of the SMC value as a weighted mean value with event runoff volumes as weights is affected by uncertainties due to the variability of event mean concentrations and to the number of events used. This study carried out on 13 catchments gives orders of magnitude of these uncertainties and shows the limitations of usual practices using few measured events. The results obtained show that it is not possible to propose a standard minimal number of events to be measured on any catchment in order to evaluate the SMC value with a given uncertainty.

Dynamics of Water Quality in the Middle and Lower Reaches of the Weihe River

2014 ◽  
Vol 955-959 ◽  
pp. 3245-3258
Author(s):  
Juan Deng ◽  
Dong Feng Hu ◽  
Zhou Ping Shangguan
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Yellow River ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Pollutant Concentrations ◽  
Weihe River ◽  
Pollutant Discharge ◽  
Major Factors

The Weihe River is an upstream tributary of the Yellow River that is heavily influenced by excessive pollutant discharge. In this study, the water quality of the Weihe River was studied based on five water quality indices: CODMn (chemical oxygen demand), BOD5 (biochemical oxygen demand), NH3-N (ammonia nitrogen), DO (dissolved oxygen), and PPI (potassium permanganate index), using monitoring data collected from 13 river sections in the middle and lower reaches of the river from 2001 to 2010. Our results showed that the water quality tended to deteriorate from the upper to the lower reaches of the river. Additionally, CODMn, NH3-N and PPI were found to be the major factors resulting in water pollution over time in all river sections, but the pollutant concentrations with the interannual variability differed in every section. Therefore, many efficient and reasonable measures should be carried out to control water pollution and improve water quality in the Weihe River.

scholarly journals Influence of manure concentration as inoculum in anaerobic digestion of vinasse

2017 ◽  
Vol 39 (2) ◽  
pp. 173 ◽  
Author(s):  
Carlos Eduardo de Farias Silva ◽  
Ana Karla de Souza Abud
Keyword(s):  
Biological Process ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Microbiological Analysis ◽  
Total Solids ◽  
Major Factors ◽  
Nitrogen Contents ◽  
Subsequent Stabilization ◽  
Microbial Action ◽  
Sugarcane Industry

Vinasse, main residue of the sugarcane industry, has high pollutant content, being subjected to the use in biogas production due to the high content of organic matter non-toxic to microbial action. For a consolidated process, it is necessary to study parameters that influence the process, in which the amount of inoculum is one of the major factors in the biological process of biogas production. This study investigated the influence of the amount of manure as inoculum (0.5 to 5.5%) during the biodigestion process, evaluating variables such as chemical oxygen demand (COD), pH, biogas production, methane concentration, total solids and total phosphorus and nitrogen contents, as well as microbiological analysis in the sludge remaining in the digester. Biodigestion occurred normally, with hydraulic retention time (HRT) of 20 days, with an acidogenic phase, subsequent stabilization of pH and biogas production. The vinasse had COD and total solids reduced during biodigestion by around 67 and 40%, respectively. Biogas production was increased after the fifth day. Among the three studied conditions, there was no significant increase in efficiency of inoculum use and it can be used the lowest amount, 0.5 % (m v-1). 

scholarly journals Assessment of the Water Quality Characteristics of Kaduna River Receiving Wastewater Discharges

2019 ◽  
Vol 3 (1) ◽  
pp. 56-61
Author(s):  
H. Garba ◽  
C. A. Elanu
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Chemical Oxygen Demand ◽  
Biochemical Oxygen Demand ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Quality Characteristics ◽  
Chemical Characteristics ◽  
Mean Concentration ◽  
Concentration Levels

An assessment of the chemical characteristics of industrial and domestic wastewater discharges on seven parameters into Kaduna River on a bimonthly basis was carried out. PH, dissolved oxygen (DO), chloride, nitrite, chemical oxygen demand (COD), biochemical oxygen demand (BOD) and iron were analyzed to determine their concentration levels. From the analysis, the highest mean concentration of the parameters were 8.24 of pH, 7.7 mg/l of DO, 233.4 mg/l of chloride, 55.68 mg/l of COD, 27.95 mg/l of nitrite, 122.22 mg/l of BOD, and 17.05 mg/l of iron. After comparing with prescribed standards, it can be concluded that there is evidence of organic and inorganic accumulation of contaminants into River Kaduna.

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