Treatment Efficiency of Integrated Constructed Wetland for Domestic Wastewater

Abstract

Constructed wetlands (CWs) are considered one of the most efficient solutions for treating wastewater and reusing water resources. The present study aimed to monitor the performance of an integrated constructed wetland (ICW) located at NUST, H-12 campus, Islamabad. It has a sedimentation tank for pre-treatment, eight ponds planted with different vegetation (Typha latifolia, Pistia stratiotes, and Centella asiatica), and a FILTER (filtration and irrigated cropping for land treatment and effluent reuse) technology. The objectives of the present study were divided into the analysis of the physicochemical parameters, microbial analysis, and comparison with the past studies on the same ICW. The samples for physicochemical and microbial analysis were collected from four points, i.e., the inlet, sedimentation tank, pond 8, and collection tank. The results indicated that average temperature, pH, and DO range between 23.95-24.20, 6.95-7.20, and 2.25-3.10, respectively. Whereas other parameters showed the removal efficiency as follows: EC 10%, turbidity 73.99%, TSS 79.16%, TDS 32.60%, TS 47.22%, COD 69.01%, NO3-N 52.76%, NO2-N 50.53%, TKN 63.50%, and PO₄³⁻ 41.24%. Gram-negative bacteria with dominating microbial species such as Salmonella, Shigella, and E. coli were found to have a removal rate of up to 95%. The findings indicate that ICW is effective at removing pathogenic microorganisms, organic contaminants, nutrients, and maintaining temperature and pH changes in the water. Moreover, the comparison with past studies showed that the performance of ICW has been maintained over the years.