Use of wastewater for energy production

Pročišćavanje otpadnih voda postupak je smanjenja količine štetnih tvari do te razine da voda koja se ispušta natrag u prirodu nema štetni utjecaj na okoliš, živa bića u njemu te na zdravlje ljudi. U procesu pročišćavanja otpadnih voda nastaje mulj kao nusproizvod. Otpadni mulj predstavlja mješavinu organskih i anorganskih tvari iz vode, a može sadržavati parazite, patogene mikroorganizme, viruse te mnoge potencijalne otrovne elemente i štetne spojeve. Pročišćene otpadne vode ispuštaju se u prirodni prijamnik, a odvojeni mulj zahtjeva daljnju obradu i odlaganje kako ne bi predstavljao opasnost za okoliš i ljudsko zdravlje, sve u skladu s ekološkim i ekonomski prihvatljivim načinima. Održivi pristup upravljanja muljem podrazumijeva primjenu prikladne tehnologije obrade mulja, što bi omogućilo njegovo ponovno korištenje uz zadovoljavajuće financijske i ekološke uvjete. U Hrvatskoj taj problem oko pametnog zbrinjavanja i obrade otpadnog mulja do dan danas nije u konačnici jasno definiran ni reguliran određenim uputama, smjernicama i propisima. U posljednje vrijeme ideje o korisnosti i isplativosti gradnje kvalitetnog postrojenja za pročišćavanje otpadnih voda koja bi uključivala i obradu te oporabu proizvedenog mulja u RH postaje sve intenzivnija. Opće je poznato da povećanjem životnog standarda raste količina otpadne vode, povećanje stupnja pročišćavanja otpadne vode raste i količina nastalog mulja kojeg je potrebno obraditi. Sve to zajedno povećava troškove rada komunalnih poduzeća koji se bave odvodnjom i pročišćavanjem otpadne vode. Ovaj rad razmatra problematiku pročišćivanja otpadnih voda te mogućnosti daljnje uporabe mulja na ekološki prihvatljiv i ekonomski isplativ način, posebice u području energetike.Wastewater treatment is a process of reducing the amount of harmful substances to such an extent that water that is filled back into nature has no harmful effects on the environment, living beings in it and on human health. Sludge is formed as a by-product in a wastewater treatment process. Waste sludge is a mixture of organic and inorganic substances isolated from wastewater, and may contain parasites, pathogenic microorganisms, viruses and many potential toxic elements and harmful compounds. The treated wastewater is discharged into a natural receiver, and separated sludge requires further treatment and disposal so as not to pose a danger to the environment and human health, all in accordance with environmentally and economically acceptable methods. A sustainable sludge management approach implies the application of an appropriate sludge treatment technology, which would enable its reuse with satisfactory financial and environmental conditions. The problem regarding the smart disposal and treatment of waste sludge according to certain instructions, guidelines and regulations. has not been clearly defined or regulated in Croatia so far. Recently, the idea of usefulness and costeffectiveness of building a quality wastewater treatment plant that would include and process the recovery of produced sludge in Croatia and in the world is becoming more interesting. It is generally known that as the standard of living increases, the amount of wastewater increases and as the degree of wastewater treatment increases so does the amount of sludge that needs to be treated. All of this increases the operating costs of utility companies engaged in drainage and wastewater treatment. This paper presents the issue of wastewater treatment and the possibility of further use of sludge in an environmentally friendly and economically advantageous way, especially in the field of energy