Analysis of the water streams in cellulose and paper production : bachelor thesis

U radu je izvedena analiza tokova vode u različitim postrojenjima za proizvodnju celuloze, papira i kartona. Utvrđeno je da ova postrojenja imaju iznimno veliku potrošnju vode, čak i do 40 000 m 3 na dan uz iznimno visoka opterećenja suspendiranim tvarima (do 5 000 mg/dm 3 ), KPK vrijednosti (do 2 000 mg/dm 3 ) i BPK 5 vrijednosti (do 700 mg/dm 3 ). Obrada ovakvih voda je nužna prije ispusta u sustav javne odvodnje, a posebice prilikom ispusta u površinske vode. Primjenom procesa pročišćavanja primarnim taloženjem, koagulacijom, flokulacijom, flotacijom i sekundarnom obradom moguće je ovakve vode pročistiti do zakonom propisanih vrijednosti. Značajno manja količina vode se koristi u proizvodnji kartona što ukazuje na potrebu prikupljanja i recikliranja otpadnog papira, čime se znatno smanjuje upotreba svježe vode, korištenje kemikalija i osigurava zaštita okoliša. Analizom rezultata kakvoće obrađene otpadne vode tvornice kartona utvrđeno je da dobivene vrijednosti prelaze one propisane zakonom. Pokazatelji kakvoće otpadne vode iz tvornice celuloze i papira pokazuju da se ovakve vode mogu ispustiti u sustav javne odvodnje.The analysis of the water streams in different plants for cellulose, paper and cardboard production has been examined. These plants have extremely high water consumption, even up to 40 000 m 3 per day with extremely high loads of suspended solids (up to 5 000 mg/dm 3 ), COD values (up to 2 000 mg/dm 3 ) and BOD 5 values (up to 700 mg/dm 3 ). The wastewater treatment of these streams is obligatory before their discharge into the sewage systems, particularly in case of discharge into the surface water streams. Treatments with the primary sedimentation, coagulation, flocculation, flotation and secondary treatment, are suitable for achieving parameters subscribed by law. Significantly less water consumption is needed in the cardboard production, which indicates the need for collecting and recycling paper waste which would significantly reduce the use of fresh water and chemicals, as well as ensure environmental protection. The analysis of the quality of treated wastewater from cardboard production shows that the obtained values exceed those prescribed by the law. Indicators of the quality of wastewater from cellulose and paper production show that such water can be discharged into the public sewage system