New ORP/pH based control strategy for chlorination and dechlorination of wastewater: pilot scale application

2006 ◽  
Vol 53 (6) ◽  
pp. 145-151 ◽  
Author(s):  
H. Kim ◽  
S. Kwon ◽  
S. Han ◽  
M. Yu ◽  
J. Kim ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Reducing Agents ◽  
Free Chlorine ◽  
Treated Wastewater ◽  
Aquatic Life ◽  
Complete Inactivation ◽  
Excess Amount ◽  
Chlorine Demand

Due to its efficiency and low capital demands, chlorination has been widely used for disinfection in many wastewater treatment plants. Since the oxidation power of free chlorine is bigger than combined chlorines which are formed from the reaction between chlorine and reducing agents in water (especially, NH4+ and organic nitrogen), for effective disinfection, excess amount of chlorine is added until all the reducing agents are oxidized and free chlorine is available. After chlorination, chlorine residues in wastewater are usually reduced with SO2 or sulfites before the treated wastewater is discharged, since they are toxic to aquatic life. Addition of excess amount of SO2 or sulfite should be avoided. Otherwise, they consume dissolved oxygen in a river or stream and may have adverse impact on the aquatic life. Determination of wastewater chlorine demand and of sulfite dosages for dechlorination has been a challenge to WWTP operators, due to the dynamic characteristics of wastewater. Recently, a new ORP/pH based approach to determine chlorine demand and sulfite dosage was proposed. The method utilizes significant points occurring on the pH and ORP profiles during chlorination and dechlorination titrations. In this study, the proposed automatic titration system has been implemented into a control system to optimize chlorine and sulfite doses for a pilot scale chlorination/dechlorination system. In short, the disinfection system with the pH/ORP based controller showed very successful results; complete inactivation of total coliforms, and almost zero residual chlorines and high DO in its effluent.

New process control strategy for wastewater chlorination and dechlorination using ORP/pH

2006 ◽  
Vol 53 (4-5) ◽  
pp. 431-438 ◽  
Author(s):  
H. Kim ◽  
S. Kwon ◽  
S. Han ◽  
M. Yu ◽  
S. Gong ◽  
...  
Keyword(s):  
Control Strategy ◽  
Wastewater Treatment Plants ◽  
Treated Wastewater ◽  
Residual Chlorine ◽  
Aquatic Life ◽  
Complete Destruction ◽  
New Process ◽  
Chlorine Demand ◽  
Receiving Stream

Due to its efficiency and relatively low capital demanding, many wastewater treatment plants have applied chlorination for disinfection of treated wastewater before discharging it. However, determination of optimal doses of chlorine for chlorination and sulfite for dechlorination, which removes residual chlorine, should made to guarantee complete destruction of microorganisms in treated wastewater and to protect aquatic life in a receiving stream. In this study, a new ORP/pH based approach to determine endpoints of breakpoint chlorination and of dechlorinating titration and to optimize doses of chlorine and sulfite. In this new method, significant points on the ORP and pH profiles occurring during the titrations for chlorination and dechlorination were utilized to determine chlorine demand and sulfite dosage.

A Review of the Occurrence of Pharmaceutical Compounds as Emerging Contaminants in Treated Wastewater and Aquatic Environments

2021 ◽  
Vol 18 ◽  
Author(s):  
Rahul Silori ◽  
Syed Mohammad Tauseef
Keyword(s):  
Wastewater Treatment ◽  
Emerging Contaminants ◽  
Wastewater Treatment Plants ◽  
Pharmaceutical Compounds ◽  
Treated Wastewater ◽  
Aquatic Environments ◽  
Aquatic Life ◽  
Adverse Health Effects ◽  
Treatment Processes ◽  
Comprehensive Information

: In recent years, pharmaceutical compounds have emerged as potential contaminants in the aquatic matrices of the environment. High production, consumption, and limited removal through conventional treatment processes/wastewater treatment plants (WWTPs) are the major causes for the occurrence of pharmaceutical compounds in wastewater and aquatic environments worldwide. A number of studies report adverse health effects and risks to aquatic life and the ecosystem because of the presence of pharmaceutical compounds in the aquatic environment. This paper provides a state-of-the-art review of the occurrence of pharmaceutical compounds in treated wastewater from various WWTPs, surface water and groundwater bodies. Additionally, this review provides comprehensive information and pointers for research in wastewater treatment and waterbodies management.

scholarly journals In situ continuous monitoring of nitrogen with ion-selective electrodes in a constructed wetland receiving treated wastewater: an operating protocol to obtain reliable data

2018 ◽  
Vol 77 (6) ◽  
pp. 1706-1713 ◽  
Author(s):  
Sandrine Papias ◽  
Matthieu Masson ◽  
Sébastien Pelletant ◽  
Stéphanie Prost-Boucle ◽  
Catherine Boutin
Keyword(s):  
Continuous Monitoring ◽  
Wastewater Treatment Plants ◽  
Treated Wastewater ◽  
Ion Selective Electrodes ◽  
Calibration Data ◽  
Effluent Quality ◽  
Evaluation Of Performance ◽  
Real Performance

Abstract Constructed wetlands receiving treated wastewater (CWtw) are placed between wastewater treatment plants and receiving water bodies, under the perception that they increase water quality. A better understanding of the CWtw functioning is required to evaluate their real performance. To achieve this, in situ continuous monitoring of nitrate and ammonium concentrations with ion-selective electrodes (ISEs) can provide valuable information. However, this measurement needs precautions to be taken to produce good data quality, especially in areas with high effluent quality requirements. In order to study the functioning of a CWtw instrumented with six ISE probes, we have developed an appropriate methodology for probe management and data processing. It is based on an evaluation of performance in the laboratory and an adapted field protocol for calibration, data treatment and validation. The result is an operating protocol concerning an acceptable cleaning frequency of 2 weeks, a complementary calibration using CWtw water, a drift evaluation and the determination of limits of quantification (1 mgN/L for ammonium and 0.5 mgN/L for nitrate). An example of a 9-month validated dataset confirms that it is fundamental to include the technical limitations of the measuring equipment and set appropriate maintenance and calibration methodologies in order to ensure an accurate interpretation of data.

Determination of chlorine demand in water and wastewater chlorination by oxidation-reduction potential

2003 ◽  
Vol 3 (1-2) ◽  
pp. 313-320 ◽  
Author(s):  
R.F. Yu ◽  
W.P. Cheng
Keyword(s):  
Control Strategy ◽  
Reduction Potential ◽  
Wastewater Treatment Plants ◽  
Water And Wastewater Treatment ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
On Line ◽  
Water And Wastewater ◽  
Chlorine Demand

Chlorination is the most practical way for the destruction of pathogenic and other harmful organisms in water and wastewater treatment plants. However, highly erratic concentrations of ammonia is contained in most water and wastewater treatment plants, which will react to chlorine and seriously alter the required chlorine dosages in the control of chlorination. The conventional control of chlorine dosage is widely practical throughout the batch breakpoint chlorination test in the laboratory, which is not feasible for the requirement of real-time regulation of the chlorine demands. In this study, a simple automatic oxidation-reduction potential (ORP) titration system was developed for on-line determination of the chlorine demand. The experimental results showed that different decrease tendencies on ORP slope profiles were found to correlate to the ammonia concentrations in samples. In addition, the required chlorine demands were found to correlate to ammonia concentrations with a linear relationship. The ORP control strategy was, therefore, developed for on-line determination of the chlorine demands. Applying this ORP control strategy, the required chlorine demands were precisely predicted, and good disinfection efficiency was obtained in the wastewater chlorination experiments.

scholarly journals Determination of kinetic parameters in a pilot scale BNR system treating municipal wastewater

2013 ◽  
Vol 8 (1) ◽  
pp. 68-74
Keyword(s):  
Wastewater Treatment ◽  
Carbon Source ◽  
Kinetic Parameters ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Biological Processes ◽  
Process Kinetics ◽  
Half Saturation Constant

Kinetics for the biological processes of nitrification, denitrification and carbon oxidation were studied in the aerobic and anoxic phases of a pilot scale Biological Nutrient Removal (BNR) plant treating municipal wastewater. The configuration of the treating system is based on the combination of the UCT (University of Cape Town) design and the step feeding process in a cascade denitrification. In order to study the process kinetics and to obtain reliable values for the investigated kinetic parameters batch experiments were performed. For this purpose, continuous feeding of the treating system was interrupted for a given period of time and the pilot plant was turned into a batch mode of operation. Thereafter, addition of NO3 --N and NH4 +-N into the anoxic and aerobic compartments of the treating plant, respectively, followed, whereas adequate initial concentration of a carbon source (municipal wastewater or synthetic substrate) was ensured in the mixed liquor. Experimental data indicated that the examined biological processes followed saturation kinetics. The maximum specific denitrification rate, qDN,max , was found to obtain values, depending on the type of the carbon source, between 0,045 and 0,390 gNO3 --N/(gXHET·d), whereas the extremely low value of the half saturation constant for the denitrification process (Km,NO3-N << 1mgN/l) indicated its description by zero order kinetics. The maximum specific nitrification rate, qN,max, was determined to vary in a narrow frame, between 1,28 and 1,60 gNH4 +- N/(gXAO·d). The half saturation constant for the nitrification process, Km,NH4-N, was estimated graphically at 3,1 – 6,1 gNH4 +-N l-1, corresponding to 62 – 122 μgNH3-N l-1. These values are considered to be in good agreement with the literature. The determination of kinetic parameters can be considered as a useful tool for the process design, operation and improvement of wastewater treatment plants. Furthermore, the study of the biological process kinetics contributes to the better understanding and outline of the complicated biological processes that contemporarily take place within the various phases of BNR wastewater treatment plants.

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