Radiotracer investigation and modeling of an activated sludge system in a pulp and paper industry

Metali Sarkar; Vikas Kumar Sangal; Vijay Kumar Sharma; Jitendra Samantray; Haripada Bhunia; Pramod Kumar Bajpai; Anil Kumar; Anil K Naithani; Harish Jagat Pant

doi:10.1016/j.apradiso.2017.10.016

Radiotracer investigation and modeling of an activated sludge system in a pulp and paper industry

Appl Radiat Isot. 2017 Dec:130:270-275. doi: 10.1016/j.apradiso.2017.10.016. Epub 2017 Oct 10.

Authors

Metali Sarkar¹, Vikas Kumar Sangal¹, Vijay Kumar Sharma², Jitendra Samantray², Haripada Bhunia¹, Pramod Kumar Bajpai¹, Anil Kumar³, Anil K Naithani³, Harish Jagat Pant⁴

Affiliations

¹ Department of Chemical Engineering, Thapar University, Patiala 147004, Punjab, India.
² Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India.
³ Shreyans Paper Ltd., Ahmedgarh, Sangrur, Punjab 148021, India.
⁴ Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India. Electronic address: hjpant@barc.gov.in.

PMID: 29055256
DOI: 10.1016/j.apradiso.2017.10.016

Abstract

A radiotracer investigation was carried out in an activated sludge process (ASP) system of an effluent treatment plant in a pulp and paper industry. The system consists of an aeration tank and a secondary clarifier connected in series. The primary objective of the investigation was to measure mean hydraulic retention times (MHRTs) of wastewater and investigate the hydraulic performance of the ASP. Residence time distributions (RTD) of the wastewater were measured in an aeration tank and a secondary clarifier of the system using Iodine-131 as a radiotracer. The measured RTD data was treated and MHRTs were estimated. No bypassing was found to exist in the aeration tank and the secondary clarifier. However, the dead volume in the aeration tank and the secondary clarifier was found and estimated to be 2.34% and 4.6%, respectively. The treated curves were further simulated using suitable hydraulically representative mathematical models and detailed flow patterns in the aeration tank and the secondary clarifier were deciphered.

Keywords: Activated sludge process, Aeration tank; Axial dispersion model; Bypassing; Dead volume; Iodine-131; Mean hydraulic residence time; Radiotracer; Residence time distribution; Secondary Clarifier; Tanks-in-series with backmixing model.