Eco-Friendly Coagulant versus Industrially Used Coagulants: Identification of Their Coagulation Performance, Mechanism and Optimization in Water Treatment Process.

Nadiah Khairul Zaman,Aina Izzati Abd Rashid,Siti Aishah Basiron,Rosiah Rohani,Izzati Izni Yusoff,Muhammad Azraei Kamsol

doi:10.3390/ijerph18179164

Abstract

The evaluation of complex organic and inorganic coagulant’s performances and their relationships could compromise the surface water treatment process time and its efficiency. In this work, process optimization was investigated by comparing an eco-friendly chitosan with the industrially used coagulants namely aluminum sulfate (alum), polyaluminum chloride (PAC), and aluminum chlorohydrate (ACH) in compliance with national drinking water standards. To treat various water samples from different treatment plants with turbidity and pH ranges from 20–826.3 NTU and 5.21–6.80, respectively, 5–20 mg/L coagulant dosages were varied in the presence of aluminum, ferum, and manganese. Among all, 10 mg/L of the respective ACH and chitosan demonstrated 97% and 99% turbidity removal in addition to the removal of the metals that complies with the referred standard. However, chitosan owes fewer sensitive responses (turbidity and residual metal) with the change in its input factors (dosage and pH), especially in acidic conditions. This finding suggested its beneficial role to be used under the non-critical dosage monitoring. Meanwhile, ACH was found to perform better than chitosan only at pH > 7.4 with half dosage required. In summary, chitosan and ACH could perform equally at a different set of optimum conditions. This optimization study offers precise selections of coagulants for a practical water treatment operation.

Highlights

Worldwide, the water crisis has become a serious issue as the global population increases and climate changes worsen
The performance comparison between chitosan and the commonly used inorganic coagulants in treating some actual surface water samples from different water treatment plants (WTPs) to meet the national standard of drinking water were successfully investigated
As the pH of the water sample increases, a higher dosage of chitosan is required to meet the national standard of drinking water

Summary

Introduction

The water crisis has become a serious issue as the global population increases and climate changes worsen. Among all water treatment technologies, coagulation and flocculation have been an essential part of drinking water and wastewater treatment processes for decades [3,4]. Research and development of coagulants have been carried out intensively to improve and establish coagulants with certain properties such as being less hazardous to the environment, having high stability, and being resilient to various process conditions so as to allow maximum coagulation performances [5].

Methods

Results

Conclusion