U ovom radu istaknuta je važnost motrenja mikrobiološke kakvoće aktivnog mulja koji provodi razgradnju sastojaka otpadne vode. Dan je kritički osvrt na učinkovitost provedbe obrade otpadne vode grada Velika Gorica motrenjem pokazatelja kakvoće rada sustava i usporedbom s rezultatima navedenim u literaturi koji obrađuju otpadne vode istog podrijetla.In this paper the importance of monitoring of activated sludge microorganisms involved in biodegradation of wastewater compounds was pointed out. Also, the functioning of wastewater treatment plant of town of Velika Gorica was monitored. The critical overview on efficiency of wastewater treatment evaluated by monitored process parameters compared with results from literature for wastewater of the...