Cavitation as a potential technology for wastewater management : an example of enhanced nutrient release from secondary pulp and paper mill sludge

Sežun, Mija (author), Kosel, Janez (author), Zupanc, Mojca (author), Hočevar, Marko (author), Vrtovšek, Janez (author), Petkovšek, Martin (author), Dular, Matevž (author)

Wastewater recycling and sludge removal in the paper industry account for about 60 % of all process costs. New and environmentally friendly wastewater treatment techniques are, therefore, continually being developed. Cavitation exploitation is currently a well-investigated topic that is also interesting for the paper production industry. This study investigates efficiency of hydrodynamic cavitation alone and in combination with the addition of NaOH for the treatment of secondary pulp and paper mill sludge in order to enhance nutrient release. First, two laboratory-scale devices were tested: the blow-through and the rotating hydrodynamic cavitation generator. The latter set-up proved to be more efficient: therefore, further experiments were performed on its pilot-scale version. The results showed an increase of soluble chemical oxygen demand (CODs) by 514 mg/L, total nitrogen (Nt) by 17.4 mg/L, and total phosphorous (Pt) by 2.3 mg/L. To further increase nutrient release combination of cavitation and sludge sample alkalinization was tested. The addition of NaOH and 30 min cavitation of secondary sludge (500 L) significantly improved CODs and Nt release by 2400 mg/L and 120 mg/L, respectively. Microbiological photos revealed a definite disintegration of sludge flocks. According to our estimates, 1.9 kg of released CODs from alkaline pre-treated and cavitated sludge would cost only one euro.

• Language: English
• Keywords: hydrodynamic cavitation, nutrients, paper mill plants, secondary sludge
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2019
• Number of pages: Str. 641-649
• Numbering: Vol. 65, no. 11/12
• PID: 20.500.12556/RUL-113727
• UDC: 532.528(045)
• ISSN on article: 0039-2480
• DOI: 10.5545/sv-jme.2019.6328
• COBISS.SI-ID: 16942363
• Publication date in RUL: 29.01.2020

Record is a part of a journal

• Title: Strojniški vestnik
• Shortened title: Stroj. vestn.
• Publisher: Zveza strojnih inženirjev in tehnikov Slovenije [etc.], = Association of Mechanical Engineers and Technicians of Slovenia [etc.
• ISSN: 0039-2480
• COBISS.SI-ID: 762116

Secondary language

• Language: Slovenian
• Title: Kavitacija kot potencialna tehnologija za revitalizacijo odpadnih voda: primer povečanega sproščanja hranil iz odpadnega biološkega mulja papirne industrije
• Keywords: hidrodinamska kavitacija, hranila, papirna industrija, odpadni biološki mulj, razgradnja muljev, obdelala odpadnih voda

Projects

• Funder: EC - European Commission
• Funding programme: H2020
• Project number: 739574
• Name: Renewable materials and healthy environments research and innovation centre of excellence
• Acronym: InnoRenew CoE