Study on Distribution of Pollution Sources and Removal of Typical Pollutants in Songhua River Basin

学生名:谢　毅

研究テーマ:Study on Distribution of Pollution Sources and Removal of Typical Pollutants in Songhua River Basin

(松花江流域の汚染源分布及び典型的な汚染物除去に関する研究)

入学年月:2016.04

修了年月:2019.03

取得学位:博士（工学）

論文概要:This study focuses on the pollution source planning and water quality improvement of the Songhua River Basin, located in Northeast China. As the third-largest basin in China, it plays a crucial role in the regional ecological environment. The research highlights pollution source distribution, effective pollutant removal methods, and strategies for water quality improvement, providing recommendations applicable not only to the Songhua River Basin but also to other water bodies. The main points of the study are summarized as follows:

1. Background and Purpose: The study addresses the distribution of persistent pollutants in the Songhua River Basin and typical pollutant removal methods. The basin is divided into three subregions (Heyuan, upstream, and middle/lower reaches) based on industrial density and population. Unlike previous localized studies, this research takes a comprehensive approach to assess pollution across the entire basin.
2. Current Situation of Urban Development and Pollution Source Distribution: The majority of industrial pollution sources are concentrated in Heilongjiang and Jilin Provinces, mainly in 13 cities. Key industries include agriculture, papermaking, beverage production, and petrochemicals, which contribute significantly to heavy metals and toxic organics pollution.
3. Pollutant Monitoring and Removal Methods: Based on monitoring data from 2016 to 2019, key pollutants include heavy metals, ammonia nitrogen, COD, and others. Seasonal variations and pollution trends are analyzed using experimental methods and the seasonal Kendall test. The study proposes targeted strategies for pollution source control.
4. Analysis and Removal of Heavy Metals: Heavy metals in the basin’s sediments during different seasons were analyzed. Using nano zero-valent iron, removal efficiencies reached up to 95.5% for chromium and over 89% for lead and nickel under optimal conditions, demonstrating the effectiveness of this method.
5. Ammonia Nitrogen Removal: Taking Songyuan City as an example, horse manure was identified as a primary source of ammonia nitrogen. The study explored the use of alkali and supercritical water gasification (SCWG) for pollutant removal. Results showed that LiOH significantly increased gas yield and catalytic efficiency, with a novel 4-lump kinetic model proposed for the process.
6. Water Quality Trends: During the study period, overall water quality in the Songhua River Basin showed improvement. The research examined periodic changes in indicators such as pH, dissolved oxygen, and ammonia nitrogen, providing insights into seasonal fluctuations and aiding future predictions.
7. Relationship Between Water Quality Categories and Pollution Sources: This chapter analyzed how water quality indices influence water categories and proposed total emission control strategies. Recommendations were made for pollution source management, water quality standards, and environmental protection priorities.

This comprehensive study offers critical insights into pollutant removal and pollution control strategies for the Songhua River Basin, contributing to regional ecological sustainability and serving as a model for other water systems.