Keywords: chemical analysis; environmental engineering; field studies; metals; organic pollutants; stormwater quality; sorption capacity;
Background: A large number of metals and organic substances circulate in our society and are diffusely emitted through traffic, combustion and leaching from constructions and building materials into the urban environment. Stormwater runoff can transport pollutants from urban surfaces into storm sewers and waterways, which act as important pollutant sinks; approximately 600 specific compounds have been observed in urban runoff and rainwater worldwide. Many metals, including for example Pb, Cu Cd, Cr and Zn, are frequently detected in alarming concentrations in stormwater. Recent studies show that organic compounds like phthalates, alkylphenols, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are also ubiquitous in urban runoff. Many of these organic substances are toxic, persistent, bioaccumulating, carcinogenic, hormone disrupting and have the ability to biomagnify in aquatic and terrestrial ecosystems. It has been shown that metals and organic pollutants are presents in colloidal (defined as microscopic 1nm–1μm substances) in stormwater. Because partitioning is essential to the fate of pollutants, treatment methods for stormwater have to be reconsidered based on knowledge of partitioning between phases. The existing treatment technologies are often designed to target particulates, e.g. disc-filter with large mesh size and stormwater ponds for settleable solids, which are not removing colloid-bound pollutants. Innovative technologies addressing also colloidal pollutants are currently lacking and need to be investigated further. Filtration of stormwater is one of the most promising techniques for removal of colloidal and truly dissolved pollutants, provided that effective filtration and adsorption media is used.
Objective: Investigate the efficiency of selected sorption filters for the removal of colloidal organic pollutants and metals from road runoff through pilot-plant studies.
Approach: A pilot-plant facility with sorption filters is installed at the Järnbrott sedimentation pond, located in Göteborg, for testing of the removal of both organic pollutants and metals from stormwater. The pilot plant consists of three columns filled with sorptive materials. The plant needs frequent monitoring and maintenance, to maintain adequate flow and collect water samples. Inlet and outlet water samples from the columns will be analyzed for total, dissolved and colloidal fractions of organic pollutants and metals. Your task is to monitor, run and maintain the pilot plant, collect water samples, prepare samples for chemical analysis, and perform analyses of certain water quality parameters, in field and in our environmental laboratory at Chalmers.
Outcomes: The results will show the efficiency of sorption filters for their removal of colloidal fractions of metals and organic pollutants in stormwater.
Time frame: This project is suitable for a 30 or 60 credits master thesis. You may start working either fall 2016 (no earlier than August 15) or spring 2017.
Required qualifications: The student should have a background in civil engineering, environmental engineering, chemical engineering or equivalent. Experience in experimental work in the laboratory and pilot testing in the field is of great value. If this experience is lacking, we put a great value if you are a creative problem solver, enjoy working outdoors, and don’t mind getting your hands dirty.
It is a great asset if you have a valid driver’s license class B (or equivalent).