The BIOZO process – a biofilm system combined with ozonation: occurrence of xenobiotic organic micro-pollutants in and removal of polycyclic aromatic hydrocarbons and nitrogen from landfill leachate

2010 ◽  
Vol 61 (12) ◽  
pp. 3188-3197 ◽  
Author(s):  
Benedek Gy. Plósz ◽  
Christian Vogelsang ◽  
Kenneth Macrae ◽  
Harald H. Heiaas ◽  
Antonio Lopez ◽  
...  

We present an assessment of xenobiotic organic micro-pollutants (XOM) occurrence and removal of polycyclic aromatic hydrocarbons (PAHs) in a novel biofilm system combined with ozonation, the BIOZO concept, treating partly stabilised landfill leachate. A novel, staged moving-bed biofilm reactor (SMBBR) design was implemented in laboratory- and pilot-scale, and the PAHs removal efficiency of controlled ozonation was assessed installing the ozonation step in the nitrate recirculation line (Position 1) or between the pre-anoxic and aerobic zones (Position 2). COD removal in a laboratory- and in a pilot-scale SMBBR system with and without ozonation is additionally addressed. Results obtained in a screening study (GC-ToF-MS) were used to compile a priority list of XOMs in leachate based on relative occurrence, showing PAHs as the predominant fraction. Biological treatment is shown to be an effective means to remove PAHs detected in the aqueous phase. PAH removal takes in most part place in the pre-anoxic zone, thereby decreasing toxicity exhibited by PAH on autotrophic nitrifier bacteria in the aerobic zone. Ozonation installed in Position 2 is shown to be superior over Position I in terms of COD, PAH and nitrogen removal efficiencies. We additionally demonstrate the potential of intermittent sludge ozonation as a means to decrease PAH concentrations in sludge wasted and to improve nitrogen removal in the BIOZO system.

1996 ◽  
Vol 31 (3) ◽  
pp. 433-452 ◽  
Author(s):  
Paul Bucens ◽  
Alan Seech ◽  
Igor Marvan

Abstract In 1992, GRACE Dearborn, Inc. was contracted by Environment Canada to conduct a field-scale demonstration of the DARAMEND bioremediation technology under the auspices of the Great Lakes Cleanup Fund's Contaminated Sediment Treatment Technology Program. The demonstration on approximately 150 tonnes of sediment dredged from Hamilton Harbour was completed by January 1994. Two distinct batches of sediment were treated. One batch of 90 tonnes of sediment, dredged directly from the harbour without any pretreatment, is the focus of this paper. Sediment was received in October 1992 and was treated through to December 1993. Treatment was conducted in an high-density polyethylene-lined treatment cell that was covered by a steel framed greenhouse. The treatment involved amending, tilling and closely controlling the sediment water content. In approximately 300 days of treatment, the level of total polycyclic aromatic hydrocarbon contamination was reduced from approximately 1,000 µg/g to 100 µg/g, corresponding to a destruction and removal efficiency of approximately 90%. Notably, the high molecular weight polycyclic aromatic hydrocarbons (containing 4 to 6 benzene rings) were effectively degraded to concentrations below the Ministry of the Environment and Energy’s Soil Placement Guideline for controlled fill (MOEE 1992). The trend in the data suggest that following addition of DARAMEND amendment and several months of active management, the polycyclic aromatic hydrocarbons would continue to biodegrade as a result of the DARAMEND amendment even without active management of the sediment.


2008 ◽  
Vol 58 (11) ◽  
pp. 2069-2076 ◽  
Author(s):  
Hongtao Zhao ◽  
Chengqing Yin ◽  
Meixue Chen ◽  
Weidong Wang

Runoff with contaminated street dusts has an environmental risk to the aquatic environment. An assessment of the diffuse pollution of polycyclic aromatic hydrocarbons (PAHs) from a small town and their risks to the township stream network was conducted at Yangtze River delta. This assessment is based on measurements of 16 PAHs from the US EPA priority list by GC-MS in stream water during rainy and dry season, street dusts with different particle sizes, river sediments and suspended solids of urban runoff. The maximum level of PAHs in the stream water (2,323–4,948 ng L−1) were found during rainy season, while significantly lower PAHs concentrations (242–998 ng L−1) were measured during dry season. The total PAHs ranged from 1,629 to 8,986 μg kg−1 in the street dusts. Approximately 55% of the total PAHs were associated with street dust particles of diameters less than 250 μm and these accounted for 40% of the total. The town reaches sediments were rich in PAHs and it was suggested as the sink of street dusts. The research findings suggested that size of street dusts, the topographical and hydrological features of the landscape in the stream network were the important factors influencing PAH emitted to the receiving water. The contribution of urban surface runoff could significantly influence PAHs concentration in the stream water. To reduce the pollution of street dust into the stream network, the buffer zone along the hydrological pathway is suggested and the existing street cleaning methods should also be improved.


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