diplomsko delo
Kasper Bošnik (Author), Matevž Dular (Mentor)

Abstract

Enega izmed glavnih virov onesnaževanja okolja predstavlja odpadno blato. Večina čistilnih naprav odpadno blato najprej ustrezno obdela in ga nato odpelje na sežig. Nekatere čistilne naprave odpadno blato stabilizirajo v anaerobnih reaktorjih ter proizvajajo bioplin in tako vsaj nekoliko zmanjšajo skupne stroške čiščenja odpadne vode. Da bi povečali količino bioplina, se lahko uporabijo različne metode pred-obdelave. Eden izmed procesov, ki se lahko uporabi kot postopek pred-obdelave, je kavitacija – fizikalni pojav, kjer v tekočini zaradi lokalnega padca tlaka nastanejo majhni parni mehurčki. Ko mehurčki kolapsirajo, se sprostijo ogromne količine energije, ki so odgovorne za mehanske (tj. ekstremne strižne sile, mikro curke in ekstremne pulzacije tlaka) in kemijske (tvorba pretežno ●OH s homolizno cepitvijo molekul vode) učinke. V diplomski nalogi smo ocenjevali dezintegracijo odpadnega blata iz čistilne naprave z uporabo hidrodinamske kavitacije. Uporabili smo laboratorijsko izvedbo rotacijskega generatorja hidrodinamske kavitacije in njegovo učinkovitost preučevali pri različnih postavitvah rotorja in statorja. Uspešnost kavitacije smo določili z merjenjem relevantnih parametrov, kot so skupni in topni KPK (kemijska potreba po kisiku), topni NH4-N (amonijev dušik) in topni skupni ogljik pred in po kavitaciji. Z izračuni stopnje dezintegracije in dovedene energije smo ocenili energetsko učinkovitost postavitev. Rezultati so pokazali nizko stopnjo dezintegracije pri vseh postavitvah (< 10 %), kar nakazuje, da HC ni bila učinkovita pri razgradnji celične stene mikroorganizmov. Velja omeniti, da na učinkovitost HC vpliva obilica parametrov; celokupni vpliv je pogosto nepredvidljiv. Za najučinkovitejšo se je izkazala postavitev rotorja z 8 valjastimi zobmi brez statorja, kjer smo dosegli stopnjo dezintegracije 9,6 %. Ista postavitev je za delovanje porabila tudi najmanj energije (852 kJ/kg TS); glede na porast v topnem KPK je to pomenilo 37 kJ/g KPKtopni.

Keywords

čistilne naprave;biološko čiščenje;odpadno blato;obdelava blata;diplomska dela;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher: [K. Bošnik]
UDC: 628.336:532.528(043.2)
COBISS: 128065027 Link will open in a new window
Views: 54
Downloads: 8
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Other data

Secondary language: English
Secondary title: Evaluation of waste sludge disintegration using laboratory scale hydrodynamic cavitation generator
Secondary abstract: One of the main sources of environmental pollution is waste sludge. Most sewage treatment plants first properly treat the sludge and then take it to incineration. Some wastewater treatment plants stabilize waste sludge in anaerobic reactors and produce biogas, thus at least slightly reducing the total cost of wastewater treatment. Various pre-treatment methods can be used to increase the amount of biogas. One of the processes that can be used as a pre-treatment process is cavitation – a physical phenomenon where small vapor bubbles form in a liquid due to a local pressure drop. When bubbles collapse, huge amounts of energy are released. They are responsible for the mechanical (i.e. extreme shear forces, micro-jets, and extreme pressure pulsations) and chemical (formation of predominantly ● OH with homolytic cleavage of water molecules). In the thesis, we evaluated the disintegration of waste sludge from the treatment plant using hydrodynamic cavitation. We used a laboratory version of a rotary hydrodynamic cavitation generator and studied its cavitation efficiency under different rotor-stator installations. We have determined cavitation performance by measuring relevant parameters, such as total and soluble COD (chemical oxygen demand), and soluble NH4-N (ammonium nitrogen) soluble total carbon before and after cavitation. Through degree of disintegration and specified energy consumption, we estimated the energy efficiency of the installations. The results showed a low level of disintegration in all setups (<10%) suggesting that HC was not effective in degrading the cell wall of the microorganisms. It is worth noting that the efficiency of HC is influenced by many parameters due to which the overall impact is often unpredictable. The setup of the rotor with 8 cylindrical pins without a stator proved to be the most effective. The achieved degree of disintegration was 9.6%. The same setup also used the least amount of energy (852 kJ/kg TS), which, considering the increase in soluble COD, meant 37 kJ/g sCOD.
Secondary keywords: wastewater treatment plant;waste sludge;hydrodynamic cavitation;Odpadne vode;Univerzitetna in visokošolska dela;
Type (COBISS): Bachelor thesis/paper
Study programme: 1000372
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, UNI Kemijsko inženirstvo
Pages: 29 str.
ID: 16391579