To help solve this difficult problem, students of environmental engineering specialty (Ho Chi Minh City University of Technology) include: Nguyen Vu Phong, Bui Phu Son, Lam Thanh Dat has conducted the research on “Bio-activated sludge treatment of high-salinity aquatic wastewater”. The project has won the third prize of Student Research in 2018, organized by the Ministry of Education.
Talking about the idea to study this topic, Nguyen Vu Phong said: “Vietnam has focused on aquaculture and seafood processing for many years, because our country has many advantages as the coast long, dense river systems. At present, Vietnam is one of the 10 countries with the highest seafood export volume in the world, the export value accounts for about 4% of the country's GDP. However, high salinity effluent is a concern for both the aquaculture and seafood processing industry in particular and the environment in general”.
“Our group started to do research in the second year”, said Vu Phong. “We found that wastewater from seafood processing is very salty, containing many organic substances, solid waste and oil, not to mention the factories nearby the sea due to lack of fresh water use sea water to wash the system of machinery, it contributes to increase salinity of wastewater.
Specifically, the results of the analysis in the laboratory showed that the indexes in the wastewater exceeded the allowable limit, for example, the COD (chemical oxygen demand) index ranges from 100 to 2000 mg / L, 1 to 20 times higher the standard (80mg / L) or especially BOD (biochemical oxygen demand) ranges from 600 to 5500 mg / L, exceeding hundreds of times the standard (40 mg / L), etc.
From the result of salinity analysis of wastewater in seafood processing factories, this group of students conducted an activated sludge method with supplement of biological products to treat the salinity of wastewater.
“To ensure accuracy, the team directly collected samples from factories in Vinh Loc Industrial Park (Binh Tan District, Ho Chi Minh City). They took about 30 liters every week. The experimental system was assembled at the laboratory of Ho Chi Minh City University of Technology, including a series of activated sludge tanks supplemented by biological products, analytical equipment for wastewater indicators and projected continuously with initial salinity data. At the same time, we also compare and evaluate the salinity efficiency of two biological preparations”, said Bui Phu Son, a member of the group.
According to Son, from the researched result, the team assessed the ability of salinity treatment of the Microbe - Lift IND is better than the EM - WAT 1. “As a result of this assessment, our group has identified the salinity of the wastewater to select the optimal concentration of biological products for wastewater treatment”, Son added.
Although there have been many studies in the world and in Vietnam about the application of biotechnology to wastewater treatment, the topic of using directly liquid bio-products in wastewater is completely new.
Huong Tra (source: thanhnien.vn)