Pollutants and the water quality of the river Ralja: From the spring up to U.S. Steel Serbia d.o.o.

Abstract

In the period from July to October 2009 the examination of the water and sediment quality of the river Ralja was carried out from the spring up to wastewater inflow from the US Steel Serbia industrial complex. Water and sediment samples were taken at seven measuring points. In the watershed of the river Ralja a large number of small dispersed pollutants was identified, which discharge without any treatment, about 5500 m3/day of waste waters containing about 1600 kg BOC5, increased amount of suspended matter, iron, nitrates, occasionally phenol, nitrite, and so on. The average water flow of the river Ralja is 1.55 m3/s or 133 920 m3/day, which means that the average concentration of BOC5 in the river Ralja is 11.95 mg/l, as a result of discharge of various types of waste and precipitated waters. Bearing in mind the fact that the waters of the river Ralja belongs to 2nd Class of water for which the maximum allowable concentration (MAC) for BOC5 is 'only' 4 mg/l, one can easily conclude that the waters of the river Ralja do not meet the criteria set for the 2nd water Class. On the basis of performed physical and chemical analysis we can conclude that the riverbed of the river Ralja is converted into ordinary waste water collector. The same conclusion applies to its tributaries, which are often during the dry season, converted into waste dumps that contains hazardous materials or substances that have the character of hazardous waste. These materials represent the potential sources of infection. Microbiological analysis show that the water quality of the river Ralja is often in the 4th Class.

U periodu juli-oktobar 2009. godine izvršeno je ispitivanje kvaliteta vode i sedimenta reke Ralje od izvora do uliva otpadnih voda U.S. Steel Serbia. Uzimani su uzorci vode i sedimenta na sedam mernih mesta. U slivu reke Ralje identifikovano je veliki broj malih rasutih zagađivača, koji ispuštaju, bez ikakvog tretmana, oko 5500 m3/dan otpadnih voda, koje sadrže oko 1600 kg BPK5, povećanu količinu suspendovanih materija, gvožđa, nitrata, povremeno fenola, nitrita, itd. Prosečni protok reke Ralje je 1,55 m3/s ili 133.920 m3/dan, što znači da je prosečna koncentracija BPK5 u reci Ralji 11,95 mg/l, kao posledica ispuštanja raznih vrsta otpadnih i ocednih voda. Imajući u vidu činjenicu da voda reke Ralje pripada II klasi voda za koju je maksimalno dozvoljena koncentracija (MDK) za BPK5 'svega' 4 mg/l, lako se može zaključiti da voda reke Ralje ne ispunjavaju kriterijuma koje propisuje II klasa voda. Na osnovu urađenih fizičko-hemijskih analiza može se konstatovati činjenica da je voda reke Ralje duž celog svog toka pretvorena u obični kolektor otpadnih voda. Ista konstatacija važi i za njene pritoke, koje često preko leta i presušuju, tako da se pretvaraju u smetlišta komunalnog otpada i otpada koji u sebi sadrži opasne materije ili materije koje imaju karakter opasnog otpada. Ovakvi materijali predstavljaju i potencijalne izvore zaraze. Mikrobiološke analize pokazuju da je kvalitet vode reke Ralje često u IV klasi.