03.02.2021 Views

Water & Wastewater Asia September/October 2019

Water & Wastewater Asia is an expert source of industry information, cementing its position as an indispensable tool for trade professionals in the water and wastewater industry. As the most reliable publication in the region, industry experts turn this premium journal for credible journalism and exclusive insight provided by fellow industry professionals. Water & Wastewater Asia incorporates the official newsletter of the Singapore Water Association (SWA).

Water & Wastewater Asia is an expert source of industry information, cementing its position as an indispensable tool for trade professionals in the water and wastewater industry. As the most reliable publication in the region, industry experts turn this premium journal for credible journalism and exclusive insight provided by fellow industry professionals. Water & Wastewater Asia incorporates the official newsletter of the Singapore Water Association (SWA).

SHOW MORE
SHOW LESS
  • No tags were found...

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

24 | INSIGHT<br />

Efficient sludge thickening<br />

and dewatering: How to find<br />

the right parameters for<br />

choosing the ideal solution<br />

By Christian Dousset, Process Technology Manager, ANDRITZ<br />

Sludge thickening and dewatering are key process steps when treating wastewater. Numerous suppliers<br />

provide dozens of different machines to make this process easier – all claiming that their solution is<br />

the best, but often not taking account of the fact that several given parameters in a plant determine<br />

the success of the equipment chosen and consequently, the efficiency and profitability of operations.<br />

With no one-size-fit-all solution, how do plants find the one to fit their specific requirements?<br />

THE BEST SOLUTION – CONSIDER<br />

IT NOT ALWAYS BEING BEST FOR<br />

YOU<br />

In wastewater treatment, plants will most<br />

likely be challenged to find an efficient,<br />

reliable, and safe wastewater treatment<br />

solution that is also less costly to install,<br />

operate, and maintain, all while meeting<br />

the strictest local requirements. This<br />

challenge has not become easier, as dozens<br />

of suppliers are pushing various machines<br />

for thickening and dewatering, claiming<br />

that their technology is the best. Obviously,<br />

there is no ideal, universal solution because<br />

not every wastewater treatment process and<br />

its preconditions are the same, and every<br />

technology comes with process-related<br />

advantages and disadvantages alike.<br />

Even if only the economic arguments<br />

are considered, every project is specific,<br />

and nothing is set in stone. The variable<br />

elements could be the cost of sludge<br />

transport, the sludge’s final destination,<br />

the structure and quality in which it has<br />

to be transported, special treatment of<br />

sludges in a wastewater treatment plant<br />

requiring dedicated equipment, the plant’s<br />

geographical location, whether or not a<br />

building already exists, specific constraints<br />

such as noise or odour, energy costs,<br />

availability of special reagents like powder<br />

and emulsion polymer, as well as qualitative<br />

discharge constraints like granulation or<br />

storage capabilities.<br />

SIZE DOES MATTER – CONSIDER<br />

YOUR SURROUNDINGS<br />

The required footprint of a machine is an<br />

essential factor in wastewater treatment<br />

plants, both those in planning and also those<br />

that are already up and running. When space<br />

is limited, a decanter centrifuge presents<br />

itself as a potential solution: Not only is the<br />

space required to install these machines<br />

smaller than for all other dewatering and/<br />

or thickening units (which has an impact on<br />

the civil engineering costs), this technology<br />

also features an excellent capacity/size<br />

ratio. Its versatility in the treatment of<br />

various types of sludge, combined with<br />

this advantage, make it a popular solution –<br />

also for mobile dewatering units.<br />

But if conditions like a municipality’s<br />

population and the wastewater it produces<br />

are likely to change in the future, a gravity<br />

belt table seems to be a good thickening<br />

solution thanks to its high hydraulic capacity.<br />

Another thing to consider when checking<br />

whether a machine fits into a plant is the<br />

surroundings. Depending on the location<br />

and the neighbouring buildings, the noise<br />

from the machine as well as the ability to<br />

reduce the often-terrible odour coming<br />

from the treated sludge should not be left<br />

unconsidered when choosing the right<br />

technology. When noise and especially<br />

odour are of concern, it is better to choose<br />

a closed system instead of an open one –<br />

the reasoning behind this is simple: Foul<br />

odours and distractive sounds are contained<br />

if the system is enclosed. A common closed<br />

system for thickening with verified benefits<br />

in clean rooms and odour prevention is the<br />

drum thickener – which is also very compact<br />

in terms of capacity. When searching for<br />

a closed system for dewatering, a screw<br />

<strong>Water</strong> & <strong>Wastewater</strong> <strong>Asia</strong> • <strong>September</strong> / <strong>October</strong> <strong>2019</strong>

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!