Treatment of Organic Contaminants: Biological Treatment

A full-scale (470 m3) process for biological treatment of dredging spoil from the Petroleum Harbour in Amsterdam has been monitored during a pilot project. The dredging spoil was heavily polluted with polycyclic aromatic hydrocarbons (PAH) and mineral oil. The remediation chain involved dredging, transport of dredged spoil, hydrocyclone separation, froth flotation of the coarse particles, and biological treatment of the silt fraction (<20 μm) in stirred bioractors. The independent monitoring was aimed at recording the environmental effects, product quality and performance of the biological process. Hydrocyclone separation (cut point 20 m) resulted in two bulk streams: 65% sand and 30% silt (based on total dry weight of the input). The sand was cleaned and could be reused as building material. PAH and mineral oil were successfully concentrated in the silt fraction (<20 μm), which was treated biologically. Biological treatment during continuous feeding of fine fraction, at a residence time of 8-10 days for the entire bioreactor system, resulted in considerably reduced mineral oil and PAH contents. Furthermore, the leaching of organic contaminants was reduced, as well as the ecotoxicity. The obtained silt product however did not meet the demands, and had to be landfilled. Minor emissions of contaminants were measured in wastewater and offgas. The energy and chemicals consumption were acceptable. The biological process appears to be promising for the treatment of less-severely contaminated dredged material.

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Short investigation on occurrence and removal of semivolatiles during wastewater treatment processes

Romanian Journal of Ecology & Environmental Chemistry ◽

10.21698/rjeec.2021.216 ◽

2021 ◽

Vol 3 (2) ◽

pp. 130-140

Author(s):

Maria Diana Puiu ◽

Keyword(s):

Wastewater Treatment ◽

Organic Contaminants ◽

Biological Treatment ◽

Organic Matter Content ◽

Treatment Plant ◽

Oxygen Demand ◽

Matter Content ◽

Physical Treatment ◽

Dissolved Air Flotation ◽

Treatment Processes

The food industry wastewater is known to present a high organic matter content, due to specific raw materials and processing activities. Even if these compounds are not directly toxic to the environment, high concentrations in effluents could represent a source of pollution as discharges of high biological oxygen demand may impact receiving river's ecosystems. Identifying the main organic contaminants in wastewater samples represents the first step in establishing the optimum treatment method. The sample analysis for the non-target compounds through the GC-MS technique highlights, along with other analytical parameters, the efficiency of the main physical and biological treatment steps of the middle-size Wastewater Treatment Plant (WWTP). Long-chain fatty acids and their esters were the main abundant classes of non-target identified compounds. The highest intensity detection signal was reached by n-hexadecanoic acid or palmitic acid, a component of palm oil, after the physical treatment processes with dissolved air flotation, and by 1-octadecanol after biological treatment.

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