Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hydrothermal liquefaction of sewage sludge; energy considerations and
  fate of micropollutants during pilot scale processing   The beneficial use of sewage sludge for valorization of carbon and nutrients
is of increasing interest while micropollutants in sludge are of concern to the
environment and human health. This study investigates the hydrothermal
liquefaction (HTL) of sewage sludge in a continuous flow pilot scale reactor at
conditions expected to reflect future industrial installations. The processing
is evaluated in terms of energy efficiency, bio-crude yields and quality. The
raw sludge and post-HTL process water and solid residues were analyzed
extensively for micropollutants via HPLC-MS/MS for target pharmaceuticals
including antibiotics, blood pressure medicine, antidepressants, analgesics,
x-ray contrast media, angiotensin II receptor blockers, immunosuppressant drugs
and biocides including triazines, triazoles, carbamates, a carboxamide, an
organophosphate and a cationic surfactant. The results show that a positive
energy return on investment was achieved for all three HTL processing
temperatures of 300, 325 and 350 {\deg}C with the most beneficial temperature
identified as 325 {\deg}C. The analysis of the HTL by-products, process water
and solids, indicates that HTL is indeed a suitable technology for the
destruction of micropollutants. However, due to the large matrix effect of the
HTL process water it can only be stated with certainty that 9 out of 30
pharmaceuticals and 5 out of 7 biocides products were destroyed successfully
(over 98% removal). One compound, the antidepressant citalopram, was shown to
be moderately recalcitrant at 300 {\deg}C with 87% removal and was only
destroyed at temperatures $\geq$325 {\deg}C ($>$99% removal). Overall, the
results suggest that HTL is a suitable technology for energy efficient and
value added sewage sludge treatment enabling destruction of micropollutants.

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The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess