Sludge drying reed beds

IRIDRA gestione ecosostenibile delle risorse idriche

Sludge drying reed beds (SDRBs) or Sludge Treatment Reed Beds (STRBs) is a constructed wetland solution used for the management of sludge coming from big activated sludge treatment plants. SDRBs are able to fully substitute conventional sludge lines, leading to economic advantages in terms of sludge treatment and allowing a safe reuse in agriculture of dried sludge. SDRBs can also be used for in-situ treatment of sludge coming from septic and Imhoff tanks.

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No complicated mechanical equipment

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Low and simple maintenance

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Almost negligible energy consumption

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Reduced leachate production

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More than 50% reduction of operational and maintenance costs

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No chemicals

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No hygienic issues

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High flexibility, i.e. high capability in terms of sludge accumulation

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High reduction of total solids during the mineralization phase

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Good landscaping

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Possibility to reuse the dried sludge in agriculture

Sludge drying - IRIDRA's solutions

Sludge drying reed bed (SDRB)

Worldwide experiences

Several sludge drying reed beds (SDRBs) were implemented in Denmark, Germany and France in last years. For insance, up to 150 are currently implemented in France, with an increase rate of 20 SDRB plants per year. More than 70% of WWTPs above 100,000 PE are nowadays equipped with SDRBs in Denmark.

Italian experience

The Water Utility Acque Spa has installed a couple of SDRB systems for small and medium size WWTPs (2,000-10,000 PE) in Tuscany Region, highlighting the advantages in terms of costs in comparison to conventional technological solutions (Giraldi et al., 2008, Ceccanti et al., 2010). IRIDRA has also designed a SDRB for the drying of sludge from a septic tank serving the winery of Casorzo (AT - Italy), which produce 30.000 qt of wine per year.

SDRB vS traditional centrifuge

fitodisidratazione comparison

SDRB examples

fitodisidratazione kolding web

SDRB of Kolding (Denmark) for 125,000 PE and an extension of 3.3 ha (Source: Steen Nielsen, Orbicon)

fitodisidratazione casorzo web

SDRB of Kolding (Denmark) for 125,000 PE and an extension of 3.3 ha (Source: Steen Nielsen, Orbicon)

IRIDRA's projects

IRIDRA progetto per Villaggio di Sarra, Nablus (Palestina)

Zanzibar (Tanzania)

Design flow: 50-100 m3/d

Chosen Nature-based solution: SDRB

Year of realization: 2020

The project concerns the treatment of leachate from a landfill site in Kibele by means of waste stabilisation ponds and FWS for 100 m3/d + Planting of a constructed wetland for faecal sludge management with a capacity of 50 m3/day.

Sarra village, Nablus (Palestine)

Treated person equivalent : 4300 PE

Chosen Nature-based solution : SDRB

Peculiarity : In-situ treatment of sludge from septic tanks with consistent reduction of O&M cost. Project financed by the European Union

Year of realization : 2012-2013

Sarra village, Nablus (Palestine)

IRIDRA's missions in Palestine - Sept 2011 "DESIGN OF WASTEWATER TREATMENT PLANT IN SARRA (3500 pe - NABLUS) AND REHABILITATION OF CONSTRUCTED WETLAND SYSTEM IN HAJJA (700 pe -QALQYLIA) – WWTP START-UP AND STAFF TRAINING done in WEST BANK, oPT - The project "Making wastewater an asset: increasing agricultural production introducing irrigation by non-conventional water sources" is managed by the NGOs GVC, PHG and UAWC and is financed by the EU - DCI-FOOD/2010/254-819.
The two WWTP has been officially started in October 2014.

IRIDRA progetto per Cantina sociale di Casorzo (AT)

Casorzo Winery (AT - Italy)

Wine production : 30,000 ql. of produced wine per year

Chosen Nature-based solution : SDRB

Peculiarity : In-situ treatment of sludge from septic tanks with consistent reduction of O&M cost

Year of realization : 2004

In 2004, IRIDRA managed a project of constructed wetlands for the wine-producing firm “Cantina sociale di Casorzo”, at Casorzo, Italy. The new system (HF + FWS, and VF to sludge drying) aims at treating the firm’s wastewater and the sludge deriving from the primary treatment.

Ordnance Factory, Nagpur (India)

Treated person equivalent : 1000 PE

Chosen Nature-based solution : SDRB

Peculiarity : In-situ treatment of sludge from anaerobic digester with consistent reduction of O&M cost. Plant realized under the European funded project NaWaTech

Year of realization : 2015

The entire system is designed for 1000 p.e. (100 m3/day), and the treated water is proposed for reuse of watering the multi-purpose garden and sports complex. There is a main treatment line with anaerobic treatment + subsurface horizontal upflow (HF) constructed wetland), and a pilot line with French wetland + short rotation plantation (SRP). The sludge produced by the AD is treated by 3 Sludge Drying Reed Beds units. The vertical flow CWs i.e. French Reed Beds (FRBs) are being implemented on pilot scale (5 – 8 m3/day) for demonstration of raw sewage management. The size of the SRP was adapted to this amount under consideration of the PET (potential evapotranspiration). SRPs are plantations of fast-growing trees regularly harvested in short intervals for the production of mainly fuel- and pulpwood. The fast growth leads to a high uptake of nutrients from the wastewater (high treatment efficiency).For the SRP wastewater treatment systems in Nagpur local species suitable for waste water treatment were selected: Meliadubia and Bambusabambos. Domestic wastewater pre-treated in a French type of constructed wetland will be applied to the SRP via drip irrigation. Only in the dry season irrigation will take place, no wastewater application will occur during monsoon.

Sludge drying reed beds

Sludge drying - IRIDRA's solutions

IRIDRA's projects

Zanzibar (Tanzania)

Sarra village, Nablus (Palestine)

Sarra village, Nablus (Palestine)

Casorzo Winery (AT - Italy)

Ordnance Factory, Nagpur (India)

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