ISSN 2319-5347, ISI Impact Factor: 0.763

VOLUME 02  NO. 04 OCTOBER 2014:

Title:          Performance evaluation of central effluent treatment plant in Depz, Savar, Bangladesh
Authors:     Ahmud Fahim, Kh. Mahbub Hassan
Abstract:    Wastewater management is a concept involving several operations, which depend on the scale and nature of industry or institution and end use of wastewater. Central effluent treatment plant (CETP) is an approach of treating effluents by means of a collective effort mainly for a cluster of small scale industrial units.A biometric CETP was launched in Dhaka Export Processing Zone (DEPZ) and started operation for wastewater treatment in February 2012. It was the first of its kind in Bangladesh to utilize a Bio-Electric treatment profile on a co-mingled industrial wastewater stream with an average wastewater inflow of 1750 m3/hour.The treatment system offers tremendous advantages. Operating costs were low compared to chemically enhanced treatment and provided substantial difference (as much as 85% less) in sludge generation. It also had positive removal impacts on other contaminants that might appear as a part of total (co-mingled) wastewaters entering CETP from DEPZ factories. In this case, the use of chemicals was totally avoided and hence not required any neutralization as well as minimization of secondary pollutions by added chemicals. The present study was undertaken to evaluate the performance of the biometric CETP especially with regards to effluent water quality.Wastewater samples were collected from Primary and Secondary stages of treatment units and the major water quality parameters such as pH, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD),Total Suspended Solids (TSS) and Total Dissolved Solids (TDS) were analyzed following the standard methods for the examination of water and wastewater. The Primary-stage treatment operation was done with Activated Sludge Process while the Secondary-stage involved Electro Contaminant Removal. Finally, the effluents from the biometric CETP were compared with the Bangladesh Standards for wastewater quality discharging into various receiving bodies. The Environment Conservation Rules (ECR, 1997) of the country has set a range of water quality  for different receiving bodies such as Inland Surface Water, Public Sewer, and Irrigated Land. In biometric CETP, the removal efficiency of BOD was found to be 97.40% while the Dissolved silica,
Clays, Carbon black and Suspended materials in water were removed generally around 98%. The Treatment Plant reduced Bacteria, E-coli and Viruses almost completely. Emulsified oily substances as well as heavy metals in water such as arsenic, cadmium, chromium, lead, nickel, and zinc were removed in the range of 95 to 99%. Both the primary and secondary stages of treatment operations were found to have significant contribution in the overall treatment performance of the biometric CETP upholding the final effluent quality within the permissible limits of ECR, 1997.

Keywords:  Bio-Electric treatment, Central Effluent Treatment Plant, Co-mingled Industrial Wastewater,Performance Evaluation
Pages:       315-321

Download Full Paper