Improving the efficiency of urban wastewater management, case study of Hanoi City, Vietnam
Creators: name: Nguyen, Trang
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 350706
subject: International business

description: The pressing issue of wastewater management in urban areas of developing countries demands comprehensive research to address institutional and technical challenges effectively. This thesis focuses on “Improving the efficiency of urban wastewater management with a specific case study in Hanoi City, Vietnam.” The urban wastewater pollution in Hanoi, stemming from the direct discharge of daily-life wastewater into natural sources, poses a grave environmental threat. Currently, centralized wastewater management (CEWWM) is the predominant approach in Hanoi, but its effectiveness in the Vietnamese context is questionable. The study aligns with the Ministry of Natural Resources and Environment's shift toward decentralized wastewater management (DEWWM).
The objectives of this research encompass a thorough assessment of the technical and institutional aspects of wastewater management in Vietnam, the optimization of a nature-based treatment system for suburban Hanoi, and an evaluation of the proposed model's effectiveness at the city level in terms of environmental and economic management.

To address these objectives, the study formulates three research questions. Firstly, how has the wastewater system been treated and managed technically and institutionally in Vietnam? What are the issues of the wastewater management system in Hanoi? (RQ1). Secondly, what is the optimal model for a NBS treatment system based on MSL utilizing local material to filter wastewater of the Hanoi suburb? (RQ2). Lastly, what is the optimal combination between CWWT and DWWT using the proposed MSL treatment system in the study area in terms of economic and environmental benefits? (RQ3).

Hanoi faces severe wastewater pollution due to rapid growth and inadequate infrastructure. Untreated wastewater directly enters waterways, heavily polluting them. This necessitates immediate action to develop effective wastewater management solutions. Hanoi's wastewater management improvements include private sector involvement, digital document management using advanced technology, and a stronger policy framework. As the capital, Hanoi benefits from significant resource allocation. Wastewater management struggles in Hanoi due to unclear responsibilities between ministries, complex licensing processes, an ineffective monitoring system, and insufficient staffing and funding. These challenges prevent comprehensive and efficient management. 

The research employs a mixed-method approach, incorporating surveys from 195 residents and conducting twenty in-depth interviews with experts, lecturers, and managers experienced in wastewater treatment and management. The study explores green technological options, emphasizing nature-based treatment systems (NBTs) that operate through a complex synergy of soil, water, vegetation, and atmosphere to reduce the negative impact of untreated wastewater on surface water bodies. 

The research culminates in the development of a decentralized wastewater treatment model using local soil and rock materials to treat wastewater at the source. This model utilizes the MSL technique, incorporating laterite, sandy soil, zeolite, and Phragmites australis plantings. The study evaluates the efficiency of this model by measuring pollutant concentrations such as Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), total nitrogen (TN), and total phosphorus (TP).

This research has shown that: 1) The technique of treating wastewater using CWs with filtration plants can treat domestic wastewater. 2) The model of adsorbent materials combined with Phragmites australis and vertical top-down flow for best wastewater treatment results. The treatment efficiency of N and P reaches about 50% and 70% respectively. 3) Model of adsorbent combined with planting trees has good potential to treat domestic wastewater in suburban areas or rural areas of Vietnam, contributing to reducing environmental pollution. 4) Around the Phragmites australis root area, the DO content is higher than other areas in the column. The root zone of the top-down flow filtration model (CT2) has the highest value (&gt; 6mg / l). 5). The model of adsorbent combined with planting trees has good potential to treat domestic wastewater in suburban areas or rural areas of Vietnam, contributing to reducing environmental pollution.

Furthermore, the study employs Cost-Benefit Analysis (CBA) to compare the application of decentralized wastewater management (DEWWM) with conventional centralized wastewater management (CEWWM) in Thanh Oai district, Hanoi. The technique of combining soil materials and planting P. australis for efficient wastewater treatment demonstrates promising results, with cost-effectiveness, environmental protection, pollution reduction, and reduced load on centralized wastewater treatment systems being notable advantages. This research contributes valuable insights to the field of urban wastewater management, particularly in the context of developing countries like Vietnam.