Alexander Szabo and Oscar Engle - Svenskt Vatten
Alexander Szabo and Oscar Engle - Svenskt Vatten
Alexander Szabo and Oscar Engle - Svenskt Vatten
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9. Proposals for upgrading of the treatment system<br />
<br />
Alternative 1: Upgrading of existing WSP<br />
The existing WSP has advantages since it does not consume any energy <strong>and</strong> the required<br />
maintenance is low. With some, relatively inexpensive adjustments the pond system could<br />
operate more efficiently.<br />
Proposed new design<br />
• Installing screening device<br />
• Rearranging the water flow<br />
• Installing baffles in two ponds<br />
Figure 9.1: Overview over current pond arrangement (left) <strong>and</strong> upgraded alternative 1 (right)<br />
(<strong>Szabo</strong> & <strong>Engle</strong>, 2010).<br />
The purpose of rearranging the water flow to one long train of 4 ponds, instead of two parallel<br />
lines with two ponds in each (Figure 9.1), is both theoretically <strong>and</strong> practically motivated. The<br />
theoretical benefit is due to the enhanced plug-flow behavior of water when more ponds are used<br />
after each other (see Chapter 3.5 <strong>and</strong> 2.3 - Disinfection). The practical evidence was seen in<br />
Christchurch (NZ), where a similar rearrangement was done <strong>and</strong> significant reduction of<br />
pathogens, BOD <strong>and</strong> TSS (Masterton District Council, 2009) took place. The benefits of<br />
installing baffles are discussed in Chapter 5.1.<br />
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