An innovative greywater treatment system for urban areas ... - SuSanA

treatment plants in different circumstances such as in buildings where people stay overnight,
where an advantageous water balance is much easier to achieve by accumulation of
showering and bathing water. Examples of such buildings are apartment buildings, halls of
residence, hospitals, hotels etc.; here the demand of water is high and therefore the
production of greywater as well.
3.5.2 FICTITIOUS 4-STAR HOTEL IN BERLIN - ECONOMIC ASPECTS
In comparison the fictitious 4-star hotel calculation of company HUBER SE shows better
results regarding economic issues and amortisation (Paris, 2009a). The HUBER GreyUse®
unit is installed in the cellar of the building and the additional tubing system can be built in
simply, due to modular design of the structure.
The investment and operation costs of the HUBER GreyUse® unit are summarised in
Table 23. Included in the annual maintenance is the exchange of faulty membrane module
and replacement of worn parts. This ensures a lifecycle of 15 years without any problems.
With drinking and wastewater charge of 4.73 €/m³ (net) in Berlin the cost savings resulting
from the use of greywater recycling are calculated. The assumptions of price increase for
water are 2% and for energy 5% in the preceding years. According to the scenario the
payback period is approximately 6 years of operation (see Figure 21). After 10 years of
operation 39,369 € expenses can be saved (Paris, 2009a).
Table 23: Economic cost calculation (net) of fictitious 4-star hotel in Berlin; (Paris, 2009a)
Treatment plant HUBER GreyUse® 33,089 €
Tubes and piping system 18,000 €
Total invest
(interest rate 2%/a)
Costs of maintenance incl. wear parts
(price increase 2%/a)
Energy costs
(0.1379 €/kWh; price increase 5%/a)
51,089 €
2,012 €/a
1,179 €/a
Summary of operation costs 3,191 €/a
Water price (fresh and wastewater) 12, 537 €/a
Total cost saving – difference between saved
water costs and operation costs
(water price 4.58 €/m 3 , price increase 2%/a)
9,347 €/a
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