The Reuse of Washings from Pool Filtration Plants After the use of Simple Purification Processes

Abstract

The necessity of regular filter backwashing in the pool water technological systems generates enormous, unproductive water losses. In order to properly wash the filter bed, a water consumption of 4÷6 m 3 per 1 m 2 of bed is required. According to the guidelines, such backwashing should take place every 2÷3 days [1-6]. It can be estimated that the monthly water consumption for a typical installation, consisting of two filters with a diameter of 1800 mm, can be over 450 m 3. Every year, it is over 5 000 m 3 of unproductive wastewater discharged usually into the sanitary sewage system. In Poland, there are over 560 pools equipped with at least 2 filters [7]. Therefore it can be estimated that annually more than 2 800 000 m 3 of backwash water is lost. Assuming the average price for wastewater discharges in large cities, 1.48 €/m 3 , it is easy to estimate that over 4 million € per year is spent on discharging "pool" washings [8]. In addition, the water used to backwash filtration beds is usually taken from the technological system where it was previously heated. The temperature of washings ranges from 25°C to 36°C (average about 30°C). For this reason, its discharging into the sewage system is also a waste of energy used to heat it. In the Institute of Water and Wastewater Engineering of the Silesian University of Technology, the research on the quality of backwash water from swimming pool installations is being conducted. Their main purpose is to check the possibility of managing the backwash

Water loss in swimming pool filter backwashing processes in the Balearic Islands (Spain)

“…Therefore, backwash water must be treated before discharging it to a watercourse. Simple purification processes, including sedimentation with coagulant followed by intensive aeration, allow the backwash water to be introduced into waters or the ground (Wyczarska-Kokot & Lempart, 2018. The reuse of the backwashing water is a better option.…”

“…Advanced procedures like membrane filtration (micro-, nano-or ultrafiltration) or ultraviolet irradiation are increasingly used for pool water treatment (Skibinski et al, 2016(Skibinski et al, , 2019. Simple purification processes, including a settling tank with a coagulant chamber and after a tank for intensive aeration, allow the backwash water to introduce into waters or the ground (Wyczarska-Kokot & Lempart, 2018). The simple filtration with granular activated carbon effectively removes free chlorine and DBPs from the water, as demonstrated by Skibinski et al (Skibinski et al, 2019).…”

Application of the Swimming Pool Backwash Water Recovery System with the Use of Filter Tubes

“…When analyzing the possibilities of reducing water consumption and wastewater discharge in swimming pools, more and more attention is paid to filtration washings (backwash water-BWW) [7,8]. The need for regular backwashing of filter beds in the technological systems of swimming pool water generates huge, unproductive losses of water [9]. The filter beds are rinsed once every 2-4 days to meet the physicochemical and sanitary requirements of water quality [10][11][12][13].…”

“…It is estimated that in Poland over 2,800,000 m 3 /year of backwash water is lost, which causes costs of over EUR 4 million as a result of discharging backwash to the sewage system [9]. Moreover, water used to backwash the filter beds is usually taken from the technological system in which it was previously heated.…”

“…So far, the possibilities of backwash water management have been tested using simple but relatively expensive individual processes (adsorption, coagulation, filtration, electrocoagulation, electroflocculation) and devices (for example, sedimentation tanks, settling tanks, clarifiers or settling tanks coupled with a coagulant chamber). However, this does not purify the water sufficiently and does not meet stringent standards [8,9,[15][16][17][18][19].…”