<p> This thesis focuses on the thermal plasma treatment of non-point source
pollutants accumulating in stormwater ponds. Stormwater ponds are constructed
as a part of urban non-point source pollution control systems. Pollutants from
various sources are collected in the stormwater ponds as sediments. In this work,
stormwater sediments were first separated by a filter with an opening of 208μm.
The filtered sludge-water was subjected to pulsed arc electrohydraulic discharge
(PAED) treatment while the solid part (i.e., wet sludge and dried PAED treated
sludge) was subjected to thermal plasma treatment under non-DC transferred and
partial transferred operation modes. The results from the PAED sludge-water
treatment show that the reduction of TOC in sludge-water was approximately
80% and was greater than 90%, respectively, after 5 minutes and 2 hours of
PAED treatment. The accumulated gaseous concentrations of CxHy, CO, C02,
S02, H2S and NO emission from sludge-water treatment were 8.2, 3.1, 1.9, 0.32,
0.29 and 0.07 mg/L, respectively, after 2 hours of PAED treatment. The
concentrations of volatile elements in sediments such as S, Br, Cl and K decreased
approximately 80, 90, 30 and 20% respectively. The solid-phase carbon was
observed to be approximately completely removed after treatment. Based on the
above results, it can be concluded that PAED successfully degraded organic
compounds into C02, CO and CxHy, and converted sulfur and nitrate compounds
into S02, HzS and NO. </p> <p> Thermal plasma wet-sludge treatments showed that a reduction of TOC
was approximately 52% with argon plasma gas and air flow rates (in the reaction
zone) of 24 and 2.4 L/min, respectively. Based on SEM images, wet sludge was
melted under partial transferred mode. Thirteen elements with concentration
relationships of 0 > Si > Al > Ca > S >Fe> K > Mg > Na > Cu > C > Ti > Cl
were quantified by the X-ray energy dispersion technique. The elemental weight
percentages of Si, K, Fe and 0 increased with increasing reaction zone air flow
rate, while Ca and Cu decreased with increasing air flow rate. Thirty two elements
were quantified by Neutron Activation Analyses (NAA) but only 27 elements
were above the detection limits. Major elements (concentration> 1000 ppm) with
relative concentrations of Ca > Al >Fe> K > Mg > Na > Ti > Cl; minor elements
(100 - 1000 ppm) with relative concentrations of Mn > Ba > Sr > Zn; and trace
elements(< 100 ppm) with relative concentration were Mo > V > Cr > Br >La>
As > Sc > Th> As > Co > Dy > W > Sb > Eu; were determined. Concentrations of
Zn, La and Co were enriched 90, 50 and 30% on average respectively, while
concentrations of Br, W and As decreased by 80, 50 and 20% on average
respectively. The chemical compositions in sludge were quite different after
thermal plasma treatment. The average percentages of sand (Si02) and calcite
(CaC03) decreased 35 and 10% respectively, while compounds such as KAlSi08,
Fe304, NaCl and CaS04 were formed after thermal plasma treatment. Gaseous
hydrocarbons, H2S, CO and NO were emitted continuously during the thermal
plasma treatment of sludge. Higher reduction of organics and sulfur compounds and suppression of NOx formation were observed in the thermal plasma treatment
of wet sludge. The integrated system consisting of PAED sludge-water treatment
and thermal plasma wet sludge treatment under partial transferred mode may
provide a potential for stormwater pond sediment treatment control. </p> / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19369 |
| Date | 04 1900 |
| Creators | Li, Oi |
| Contributors | Guo, Yiping, Chang, Jen-Shin, Civil Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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