Treatment of municipal wastewater with ultrafiltration

Ekonomična i učinkovita obrada komunalnih otpadnih voda (KOV) neophodna je iz razloga što otpadna voda sudjeluje u hidrolitičkom ciklusu, ciklusu kruženja elemenata i predstavlja životnu okolinu flore i faune. Glavni cilj ovog rada bio je ispitati učinkovitost ultrafiltracijskih (UF) membrana prilikom obrade komunalne otpadne vode ultrafiltracijom. UF je provedena s MW membranom pri 2 bara i GK membranom pri 5 bara. Praćena je promjena fluksa s vremenom pri čemu je došlo do ireverzibilnog membranskog blokiranja MW membrane koje se očitalo iz pada fluksa i iznosi 78,71 %. Za GK membranu je blokiranje zanemarivo te se zbog toga pokazala kao bolji izbor prilikom obrade. Praćeni su pH vrijednost, mutnoća, električna provodnost, kemijska potrošnja kisika (KPK), biokemijska potrošnja kisika (BPK5), ukupni ugljik (TC), anorganski ugljik (IC) i ukupni otopljeni ugljik (DOC) komunalne otpadne vode i dobivenog permeata. Sastav otpadne vode i sadržaj pojedinih tvari odredio se kvalitativnom i kvantitativnom analizom pomoću ionskog kromatografa kojim su određene prisutnost kationa (Ca2+, K+, Na+, Li+, NH4+ i Mg2+) i aniona (F-, SO4 2-, NO3 -, Br-, NO2 -, Cl- i PO4 3- ). Dobiveni permeat zadovoljava granične vrijednosti propisane prema pravilniku o graničnim vrijednostima emisije otpadnih voda (NN 60/2013). Ultrafiltracijskim postupkom obrade KOV-a zadovoljeni su zakonski uvjeti što potvrđuje učinkovitost UF membrana i UF kao učinkovit membranski separacijski proces prilikom obrade KOV-a.Economical and efficient treatment of municipal wastewater (KOV) is necessary because wastewater participates in the hydrolysis cycle, the circulating cycle of elements and represents the living environment of flora and fauna. The main aim of this paper was to examine the efficiency of the ultrafiltration UF membranes during the treatment of municipal wastewater by ultrafiltration. UF was performed with MW membrane at 2 and 5 bar, respectively. There was a change in the flux over time with the irreversible membrane fouling of the MW membrane that was read from the flux and was 78.71 %. Fouling of the GK membrane was negligible and therefore proved to be a better choice during processing. Monitored parameters include pH value, turbidity, electrical conductivity, chemical oxygen demand (KPK), biochemical oxygen demand (BPK5), total carbon (TC), inorganic carbon (IC) and dissolved organic carbon (DOC) of municipal wastewater and the obtained permeate. The composition of the wastewater and the content of each substance was determined by qualitative and quantitative analysis using an ionic chromatograph to determine the presence of cations (Ca2+, K+, Na+, Li+, NH4+ and Mg2+) and anions (F-, SO4 2-, NO3 -, Br-, Cl- and PO4 3-). The obtained permeate meets the limit values prescribed by the Ordinance on Limits of Wastewater Emissions (NN 60/2013). The ultrafiltration of the KOV satisfied the legal requirements, which confirms the efficiency of the UF membranes and UF as an effective membrane separation process during KOV processing