Microbial Characterization and Water Quality Assessment of Integrated Constructed Wetland

Abstract

Inadequate sanitation system lead towards surface water contamination. In order to maintain surface water quality and decrease environmental risk, there was a need for wastewater treatment system. Objective of the current study is to monitor the efficacy of multi-stage integrated constructed wetland consisting of sedimentation tank, eight ponds of HSSF-CW and FILTER technology. Specific hydrophytes such as (Typha latifola, Pistia stratiotes, Centella asiatica) were used in treatment system. Samples were collected from ten sites including sedimentation tank (inflow), ponds and collection tank (outflow) to measure organic removal efficiency at each site. Selected physicochemical and microbiological parameters were analyzed according to standard method of examination (APHA) to demonstrate the sustained and stable removal of organics through wetland system, that includes pH, Temperature, Turbidity, Electrical Conductivity (EC), Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Total Kjeldahl Nitrogen (TKN), Nitrate, Nitrite, Phosphate, Total coliforms and Helminths quantification was carried out by using Ballinger method. Significant spatial variations were observed with higher organics removal efficiency and final effluent proved to comply with the NEQS regulations. An excellent treatment efficiency was exhibited by the water quality parameters such as COD 69%, TSS 74%, BOD 29%, Nitrite 48%, Nitrate 59%, TKN 47%, Phosphate 33%, Total Coliform 83% and Helminth eggs 100%. The high removal rates were achieved at higher temperature as well as weather parameters (Global Horizontal Irradiance and Rainfall) showed a significant positive and negative correlation with the removal efficiencies. Predominant species isolated and identified from wastewater of integrated constructed wetland belongs to the phyla Proteobacterium and Firmicute. While, predominant bacterial species isolated and identified from surface and sediment samples of different ponds includes Pseudomonas sp. and Bacillus sp. integrated constructed wetland has proved as an appropriate technology for treating domestic wastewater, land limitation is a major issue that need to be resolved. However, minor energy requirements and low principal cost are the supreme advantage for the decision makers to take into consideration.