News Updates Friday 22nd Feb 2019 :
  • Welcome to INPRESSCO, world's leading publishers, We have served more than 10000+ authors
  • Articles are invited in engineering, science, technology, management, industrial engg, biotechnology etc.
  • Paper submission last date of Jan/Feb 2019 is 23 Feb 2019, Submit online or at
  • Our journals are indexed in NAAS, University of Regensburg Germany, Google Scholar, Cross Ref etc.
  • DOI is given to all articles

Role of HRT in Biological Treatment of Combined Industrial and Municipal Wastewater

Author : Muhammad Ahmad , Zahir-ud-din Khan , Sher Jamal Khan, Muhammad Masoom Pahore and Erum Aamir

Pages : 766-774
Download PDF

A pilot scale wastewater treatment plant was designed, constructed and operated on site to treat wastewater from a combined effluent drain. The activated sludge process (ASP) was used at three different hydraulic retention times (HRT) of 12, 10 and 8 hrs at an average MLSS concentration of 3500 mg/L. Under each HRT, the pilot plant was operated for a period of 10-12 weeks. Chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC) and total suspended solids (TSS) were the major variables of interest. Average COD removal efficiency at HRT of 12, 10 and 8 hrs was 77, 80, and 87% respectively. Average BOD removal efficiency was 76, 79, and 88 % at HRT of 12, 10 and 8 hrs respectively. For the same HRTs, the average TOC removal efficiency was 64, 65 and 75% respectively. The average TSS removal efficiency was found to be 87, 90 and 96% at the given HRTs. 8 hr HRT was found to be the most appropriate in almost all cases. The average values of BOD reduced from 274.6 to 35.5 (mg/L), COD from 459.7 to 63.9 (mg/L), TSS from 528.2 to 23.4 (mg/L) and TOC from 134.3 to 33.2 (mg/L). This study proved that ASP at HRT of 8 hrs would treat the combined effluent to a level well within National Environmental Quality Standards (NEQS).

Keywords: Activated sludge process; Paharang Drain; textile wastewater; biochemical oxygen demand (BOD); chemical oxygen demand (COD); total suspended solids (TSS)

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.3(Aug- 2013)



Call for Papers
  1. IJCET- Jan/Feb 2019 Issue

    Submission Last Date
    23 Feb
  2. DOI is given to all articles
  3. Current Issue
  4. IJTT-March-2019
  5. IJAIE-March-2019
  6. IJCSB-March-2019
  • Inpressco Google Scholar
  • Inpressco Science Central
  • Inpressco Global impact factor
  • Inpressco aap

International Press corporation is licensed under a Creative Commons Attribution-Non Commercial NoDerivs 3.0 Unported License
©2010-2018 INPRESSCO® All Rights Reserved