COVER STORY — Depur Padana Acque, advanced water purification systems for industrial laundry

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Water purification plants by Depur Padana Acque meet extremely strict environmental protection requirements. The company offers a range of modular biological systems based on SBR or MBR technology with models that can easily be expanded or transferred according to clients’ needs

Depur Padana Acque, a company based in Rovigo, has been producing the industrial waste water purification systems since 1972. Founded in Italy when the environmental issues awareness was increasing and when the first laws and regulations on waste water were being established, the business grew and developed by projecting and realizing purification systems based on mechanical, chemical and biological technology. Moreover, Depur Padana Acque is focused on the realization of fully customized systems in accordance to clients’ needs while promoting, at the same time, a continuous and solid research on innovative technological solutions able to solve particularly difficult issues as well. Currently, Depur Padana Acque hires about 100 employees at the company’s headquarters and assistance centers in every Italian region in order to guarantee an efficient and reliable assistance and after-sale support.

 

“Waste purification

technology based

on mechanical,

chemical and biological

treatments”

 

Water purification plants for the Industrial Laundry sector
The sector constitutes one of the main market niches where the company operates actively. The experience gathered in the treatment of different types of waste water produced by industrial laundries, strictly connected to the origins and the type of washed linen, allows Depur Padana Acque to identify the most suitable technology to apply following the clients’ needs, the available space for the purifier and the objectives to be reached. The base technology for this type of waste water treatment is the activated sludge bio-oxidation process that translates to specific, selected microorganisms that will metabolize and eliminate the contamination present in waste water at the dissolved level. It is however necessary to consider some very important precautions and aspects that complete the big picture of the purification plants for this sector.

The MBR compartment constructed at a large Italian industrial site, textile sector (2.000 mc per day potentiality)

 

As a matter of fact, the fine screening in the pre-treatment of waste water is crucial. It is carried out by means of specific self-cleaning systems that filter solid residues like fuzz and lint released by fabrics in the washing stage. Otherwise, the material would end up obstructing the electromechanical components of the plant such as pumps or tubes, etc. As far as the biological treatment goes, the approach can be varied. Apart from the traditional systems based on the static settling of activated sludge, either in continuous mode, through a settling tank or through the discontinue sequencing (SBR – Sequencing Batch Reactor), what is often used is the innovative and already consolidated ultra-filtering membrane technology (MBR – Membrane Bio Reactor). The solution offers numerous advantages such as the possibility to realize a plant that takes half of the space needed for the traditional systems, or to double or triple the potential of the existing systems without the necessity of realizing any new tanks nor other important constructions. These purification systems allow to fully guarantee the drainage into the surface water in compliance with COD, BOD, suspended solids, grease and oils regulations obtaining exceptionally high-quality, potentially re-usable water by other various services within a business.

The new modular bio-purifiers
Depur Padana Acque has designed and realized an innovative range of modular biological purification systems, models ECOBLOCK® available in both SBR and MBR configuration. The plant (that includes the technical room with an electric panel, pumps, tanks for the reagents and other equipment) consists of a single-piece horizontal cylindrical tank, carpentry or fiberglass made, that constitutes the oxidation tank. The MBR plants include a room equipped with ultrafiltration membranes.

According to the waste water type and the volumes to treat, Depur Padana Acque thoroughly selects the most suitable membranes (flat sheet membrane, hollow fiber membrane, cross flow, etc.). Rich in experience gained over the years with more than 200 MBR plants installed in the variety of sectors, the business has acquired an important practical skill and know-how that enables to recognize and comprehend the advantages and disadvantages of each membrane type present in the world market today.

 

“ECOBLOCK®, extremely

innovative modular

bio-purifiers”

 

What is more, the ECOBLOCK® plants can be used immediately as they are provided with all the complete and necessary electrical, hydraulic and pneumatic connections, while the functional testing, at the very end of all the assembling activities, is carried out directly at the Depur Padana Acque factory. As a result, the installation operations are very fast and simple, and the time needed to start the plant is reduced to the minimum. Another innovative aspect is the modularity of the ECOBLOCK ® systems that can be enhanced by adding extra blocks also after the first installation. Moreover, it is possible to increase the volume of oxidation as a result of a possible further increase in production, or to improve the quality of the purified effluent by combining the SBR version plant to a new MBR compartment with the ultra-filtering membranes.

Waste water purification plant, ECOBLOCK® series, mono-block/compact structure equipped with the MBR technology

 

Finally, another advantage of the ECOBLOCK® system is the possibility of removing it. It can be moved as a single unit all together. This aspect is particularly interesting for those companies that operate in rented structures and that do not intend or cannot realize works such as excavations or tanks, or that need to move the headquarters and the purifier, too.

Sequencing Batch Reactor and Membrane Bio Reactor

  • The Sequencing Batch Reactor (SBR) is a biological discontinuous flow treatment system. The plant consists of a basin where processes are developed. They are carried out at different times and include biological oxidation and sedimentation. The purified effluent and excess sludge are extracted from there. The SBR reactors present interesting features: high resistance to sudden increases in organic load; all the stages of the process take place in a single basin; simple management through an automatic control of all the devices; flexible process, adaptable to various work conditions as the duration of stages can easily be modified.
  • The Membrane Bio Reactor (MBR) configuration consist of the membranes immersed in the activated sludge of the bio reactor directly in its dedicated compartment. They allow to separate the sludge and extract purified and perfectly limpid water (permeate) clean from suspended materials, from viruses and bacteria. The system, classified as BAT – Best Available Technology, allows to obtain a purified effluent that presents noticeably superior quality if compared to any other biological system. Finally, it enables not to use the flocculating coagulating chemical agents at the settling stage and to avoid disinfectants, and to completely eliminate all the issues associated to bio sludge sedimentation.

Case history The installation of ECOBLOCK® MBR plant at Gruppo Puliture Pillan industrial laundry based in Padova

 An important industrial laundry from Veneto, the Gruppo Puliture Pillan, has recently moved to an industrial area in Padova. The laundry manages flat linen treatment that comes from the hotel sector, restaurants and nursing homes for the elderly (treating both the garments of the residents and staff’s). The volume of the daily waste water is about 30 mc with a short/medium term growth forecast of up to 60÷80 mc per day. The client expressed the necessity to select a purifying plant that would guarantee a treated effluent to be in compliance with the regulations on restrictive limits in regard to waste water drainage into surface water (ref. D.Lgs n. 152/2006). What is more, the available space for placing the system at the new site was rather limited. Therefore, one of the requested features was the compactness of the plant. Another requirement referred to the flexibility and easy expansion of the system, should the need arise, as the initial volume of the treated waste water could actually double (or more than double) given the forecast on the future production expansion. All those important prerequisites were perfectly compatible with the mono-block of the ECOBLOCK® series in MBR version, that is the version equipped with the ultra-filtering membranes. The plant was then situated in an extremely reduced space taking 13m x 3,5m. The first accumulation tank of the waste water to treat (a prefabricated type, made of concrete) was placed exactly under the plant, under the ground, with the plant itself positioned above it.

Waste water purification plant, ECOBLOCK® series with a double bio-reactor, equipped with MBR technology

 

The plant has been fully running for more than a year now. The obtained purified water presents exceptional quality with values 10 times lower than the established limits for the waste water drainage. The potential of this plant, whose current configuration translates to the treatment of 40÷50 mc per day, can easily be expanded (up to its double size) by a simple introduction of a second membrane module for which it has obviously been pre-set. The MBR technology ensures the production of such high quality permeate (purified and ultra-filtered water) that the Gruppo Puliture Pillan laundry has been evaluating its partial re-use in the linen washing cycles.

 

 

 

 

DEPUR PADANA ACQUE s.r.l.
Viale Maestri del Lavoro, z.i. Borsea
45100 Rovigo RO – Italy
Tel./Ph +39 0425 472211 Fax +39 0425 474608
info@depurpadana.it
www.depurpadana.com

 

edited by Marzio Nava

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DECEMBER 2019