ΤΥΧΗ ΚΑΙ ΕΠΙ∆ΡΑΣΗ ΞΕΝΟΒΙΟΤΙΚΩΝ ΟΥΣΙΩΝ ΣΤΗΝ ... - Nemertes

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ΤΥΧΗ ΚΑΙ ΕΠΙ∆ΡΑΣΗ ΞΕΝΟΒΙΟΤΙΚΩΝ ΟΥΣΙΩΝ ΣΤΗΝ ... - Nemertes

ABSTRACT

The industrial development has brought prosperity to millions of people, but has also

left a legacy of polluted environment that continues to impact our natural resources,

and ultimately, human well being. Nowadays, many synthetic organic chemicals are

of growing concern, because of their high toxicity and high persistence in the

environment and in biological systems. Furthermore, the high lipophilicity of many of

these xenobiotics greatly enhances their bioaccumulation, thereby posing potential

health hazards.

On the other hand, sewage treatment plants (STPs) are the barriers of the

environment, where the undesired xenobiotic compounds dissolved in sewages are

biotranformed and/or sorbed to sludge. The most common method of sludge disposal

in Europe is stabilization by anaerobic treatment, thickening, and spreading on

agricultural land or landfills. This yields valuable biogas, and recycles nutrients to

agriculture, as well as conditioning of the soil.

Problems related to agricultural recycling of sludge include the presence of pollutants,

including priority pollutants identified in the EU urban water directives. These

include metals, halogenated organics, pharmaceuticals, linear alkylbenzene sulfonates

(LAS), alkylphenol polyethoxylates (APE), phthalic acid esters (PAE), and

polyaromatic hydrocarbons (PAH). Metals are currently managed by precipitation,

while halogenated aromatics are readily removed by anaerobic dehalogenation.

However, pharmaceuticals, LAS, APE, PAE, and PAH are often present in significant

quantities in the sludge. Additionally, due to their low solubility most of the

compounds will fractionate to the solids portion (i.e., sludge), rather than to the

soluble portion (i.e., effluent). As another factor, many of these compounds are

inhibitory, and the impact on digester performance is unknown.

In this work, we identify the impact of these pollutants on the anaerobic process itself,

as well as degradation of the target compounds. For the pharmaceuticals we used a

glucose based synthetic medium and continuous reactors operated in a draw and fill

mode. For the other compounds we used different types of biological sludge (primary,

secondary and mixture) and continuous stirred tank reactors (CSTR). Additionally in

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