Tidal and vertical flow constructed wetland treatment for graywater modeling and reusing with biochar cadmium adsorption
Authors: Kanfade Lekhram B. , Shingare Shyamala Prakash , Suryawanshi Mahesh A. , Kumbhar Gajanan B. , Mane Vijay B. 
Published: October 2023

This study addresses a persistent environmental concern related to graywater discharge from households, highlighting its potential to contribute to increased pollution in water bodies. To mitigate this issue, the research explores the use of subsurface flow‐built wetlands, specifically focusing on the innovative application of constructed tidal and vertical flow wetlands (CTWFWs) as wastewater treatment systems. The study not only evaluates the efficacy of these CTWFW systems but also delves into the crucial aspects of their operation and their interactions with the biological, physical, and chemical characteristics of graywater. A key innovation of this research is the investigation of zeolite's effectiveness and the utilization of perlite‐based plant species in both mixed and monoculture configurations to develop lab‐scale hybrid constructed wetlands (HCWs). These HCWs are designed for the removal of organic matter and nutrients from graywater, offering a sustainable and cost‐effective solution to this environmental challenge. The study also examines the dynamic processes involved in graywater treatment, emphasizing how the removal of parameters like biological oxygen demand (BOD), nutrients, total suspended solids (TSS), and disinfection efficiency can significantly impact the effectiveness of treatment systems. Furthermore, the research scrutinizes the intricate relationship between the treatment unit's dimensions and the specific criteria that need to be met for efficient graywater treatment. Intriguingly, the study tracks the changes in graywater composition and the treatment process over time. By conducting on‐site measurements of various physicochemical characteristics such as temperature, dissolved oxygen (DO), electrical conductivity (EC), turbidity, total dissolved solids (TDS), and pH, the research offers a comprehensive understanding of the treatment system's performance and adaptability. The study dives into the microbial communities within the treatment systems, utilizing 16S rRNA amplicon sequencing to characterize the complex microbial ecosystem present in graywater. This approach sheds light on the interplay between microorganisms, physicochemical conditions, plant responses, substrate dynamics, and the production of microbial metabolites. It underscores the holistic nature of the research, encompassing various aspects of graywater treatment. Notably, the study explores the application of biochar in combination with the target heavy metal, cadmium (Cd), within constructed wetlands (CWs). This innovative approach aims to better understand the kinetics and isothermal adsorption of lead in the context of mouthwash residue, expanding the knowledge base in this critical area. The research findings are substantial, with remarkable removal efficiencies achieved for parameters like TSS, turbidity, chemical oxygen demand (COD), nitrate, and phosphate. These results underscore the practicality and effectiveness of the proposed treatment methods. This holistic and pioneering research significantly advances the understanding of sustainable graywater treatment, offering valuable insights and practical solutions to mitigate water pollution concerns.

Practitioner Points

This study addresses a persistent environmental concern related to greywater discharge from households, highlighting its potential to contribute to increased pollution in water bodies.

The study not only evaluates the efficacy of these CTWFW systems but also delves into the crucial aspects of their operation and their interactions with the biological, physical, and chemical characteristics of greywater.

A key innovation of this research is the investigation of zeolite's effectiveness and the utilization of perlite‐based plant species in both mixed and monoculture configurations to develop lab‐scale hybrid constructed wetlands (HCWs).