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Научни трудове на Съюза на учените в България-Пловдив. Серия В. Техника и технологии, т. XV, ISSN 1311 -9419 (Print), ISSN 2534-9384 (On- line), 2017. Scientific Works of the Union of Scientists in Bulgaria-Plovdiv, series C. Technics and Technologies, Vol. XV., ISSN 1311 -9419 (Print), ISSN 2534-9384 (On- line), 2017.
IMPACT OF DAIRY WASTEWATER IN WATER POLLUTION OF A RIVER IN KOSOVO Arbёr Hyseni1, Milaim Sadiku1, Mensur Kelmendi1, NaserArifi1, LorikN Salihu2
1. University of Mitrovica“l2a Boletini”, Faculty of Food Technology,
Kosovo.
2. Master Student University of Chemical Technology and Metallurgy,
Sofia, Bulgaria.
Abstract
hhe objective of research was to ovaluato tho impact of direct discharge of dairy wastewater in a river. Dairy industry uses about 3L of water for every L of processed milC, which produces high amounts of wastewater. hhe derived wastewater from milC except water contains lactose, fats, casein and whey proteins that are organic in nature and nutrients for micro-organisms. Discharged wastewater has unpleasant odor and can causes pollution of rivers. hhe research evaluates pollution of a river through changes of some water physicochemical parameters. River s water samples were taken before and after wastewater discharge to determinate pH, oxidation reduction potential (ORP), dissolved oxygen (DO), nitrate as nitrogen (N03 - N), ammonia-nitrogen (NH3 - N) and turbidity. Results are within maximum allowed limits so can be concluded that rivers water is not polluted. Keywords: dairy wastewater, pollution, impact, river.
Introduction
Research was done in a river in which dairy wastewater is discharged in daily basis. In total 6 samples were taken for the research, tested for some water physico-chemical parameters changes that are used as indicators for river's water pollution. Dairy wastewater is discharged from the factory after milk processing and is mainly water. As water is the main component of milk, whey is mostly water and mixes with water used for cleaning. However, whey left over from the process of cheese making has relatively low pH and nutritional value as mentioned before, containing lactose, fats, casein and whey proteins. These components of whey respectively wastewater after discharge are used by micro-organisms mostly bacteria, producing metabolism products and causing unpleasant odor. This research represents the current condition of river based on some physico-chemical parameters, compares with maximum allowed limits and evaluates river's water pollution.
oethodology
Samples were taken in polyethylene bottles before and after wastewater discharge to determinate pH, ORP, DO, NO3 - N, NH3 - N and turbidity. These parameters are used as indicator of the rivers pollution and the impact of pollution comparing the sampling site where no wastewater discharge has ever happened and other sampling sites after discharging place. First lot represents the day of wastewater discharge and immediate effect in river's water whereas second 210
lot represents the next day remaining effect before upcoming daily discharge. Samples were refrigerated at 4°C and analyzed within 24h of collection. For analyzing each parameter was used respective equipment.
Results
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pH
ORP DO NO3-N NH3-N Turbidity ■ Sample 1 ■ Sample 2 ■ Sample 3
Figure 1. Variations of some river's water physico-chemical parameters for the first lot
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Hi II ■■ __ ll
ORP DO NO3-N NH3-N Turbidity
■ Sample 4 ■ Sample 5 ■ Sample 6
Figure 2. Variations of some river's water physico-chemical parameters for the second lot Discussion of results
Variations of river's water physico-chemical parameters at three different sampling sites are shown in figure 1 and 2 (Arifi, 2017). Determined river's water parameters were pH, ORP, DO, turbidity, NO3 - N and NH3 - N, which vary after discharge due to whey content and sanitation
chemicals.
pH is a measurement of hydronium ion in water and is very important parameter for aquatic life, even species are sensitive to these changes they adapt to small changes but require specific optimum pH. Aquatic shrimps and crabs require optimum pH range of 6.8 - 8.7 for maximum growth and reproduction but adverse levels are harmful (Omaka, 2014). The pH of the river is slightly alkaline in range 7.5 - 7.6. After dairy wastewater discharge it drops into neutral, mostly from low pH of whey and sanitation acids. However, in couple of meters it increases to a pH 7.27 and then back to normal. As seen form second lot of results in the three sampling sites, the other day before discharge river's pH is normal - slightly alkaline. The pH of the samples were within the acceptable limits according to EU regulation, as the standard is 6 - 9 for fisheries and aquatic life (Chapman, 1996).
ORP represents the water ability to oxidize contaminants. It is one of the essential indicators of natural and wastewater properties, used to classify the river condition; aerobic, anoxic, or anaerobic and as an indicator of the present state of the river for occurring biochemical reaction in that range (Al-Samawi, 2016). The ORP of the river was between + 8.2 mV to + 36.6 mV. Before dairy wastewater discharge ORP was + 23.6 mV whereas after discharge it drops to + 8.2 as whey has low ORP. However, in couple of meters as seen it increases to + 20.6 mV. From the second lot of results, next day before discharge river's ORP is even higher than first day + 36.6mV, which is an indicator that except in second sampling site where dairy wastewater discharged there were municipal wastewater discharges before first sampling site the day before. Surface waters and groundwaters containing dissolved oxygen are usually characterized by a range of ORP values between + 100 mV and + 500 mV (Chapman, 1996). Our study shows that river's range of OPR values is lower than values for surface waters as a result of deficiency of dissolved oxygen. ORP values for biochemical reaction of denitrification are - 50 mV to + 50 mV (Al-Samawi 2016). ORP values range shows that river's condition is anoxic and continually undergoes denitrification. DO represents the amount of oxygen that is dissolved in water and has direct impact in aquatic life.
DO is indirect measure of the degree of pollution by organic matter, the destruction of organic substances as well as self-purification of the water bodies (Ewemoje, 2014). The DO values in river where in range 1.66 - 5.97 mg L-1. Dairy wastewater discharge decreases DO level from 4.61 to 1.66 mg L-1 but its increase is slower that other parameters as organic substances are destructing and are oxygen demanding. The next day results show higher values 5.97 mg L-1 in the sampling site where no dairy discharge occurred, so is supposed that oxygen concentration decrease the first day 0.8 - 1.3 mg L-1 was caused from municipal wastewater. The standard for sustaining aquatic life is stipulated to be 5 mg L-1 and concentration below 2 mg L-1 adversely affects aquatic and biological life while the concentration below 2 mg L-1 may lead to death of fish (Ewemoje, 2014).
DO values are very low only in the point of wastewater discharge into river due to organic matter demands for oxygen while DO level increases as river's has rapid water flow and diffuses organics.
N03 - N is the measurement of oxidized form of nitrogen in water that occurs in low levels in river, however excessive amounts occurring after wastewater discharge and other activities pollute water.
Our study shows that NO3 - N is in range 2.1 - 5.8 mg L-1. When influenced by human activities, surface waters can have nitrate concentrations up to 5 mg L-1 NO3 - N, but often less than 1 mg L-1 NO3 - N. Concentrations in excess of 5 mg L-1 NO3 - N usually indicate pollution by human or animal waste, or fertilizer run-off. The World Health Organization (WHO) recommended maximum limit for NO3 - N in drinking water is 11.3 mg L-1 (Chapman, 1996). Comparing our results show that nitrate concentration are lower than 5 mg L-1 as mentioned by Chapman for surface waters, however they are higher than 5 mg L-1 only when dairy wastewater
is discharged. Nitrate of the samples were lower than acceptable limits according to WHO regulation for drinking water.
NH3 - N is a measure for the amount of ammonia, a molecule that is degradable by microorganisms but also toxic when excessive for animals, fisheries and aquatic life. Unpolluted waters contain small amounts of ammonia and ammonia compounds, usually <0.1 mg L-1 as nitrogen. Total ammonia concentrations measured in surface waters are typically less than 0.2 mg L-1 N but may reach 2 - 3 mg L-1 N. Higher concentrations could be an indication of organic pollution such as from domestic sewage, industrial waste (Chapman, 1996). Our results show that the range was 0.1 - 1 mg L-1 N. Before discharge it was typical value of NH3 - N but was high until dairy wastewater distributes in river. Results show that values of NH3 - N are typically surface waters concertation and water is not polluted, but are high while discharging that indicate organic pollution.
Turbidity represents suspended solids in water that is known as clarity of water and is measured in NTU. It is a parameter that indicates river pollution, higher it is more suspended solids are in water and less light permeates. Our case study turbidity is in the range 1.68 - 34.5 NTU. World Health Organization prescribed the highest desirable limit 5.0 NTU and maximum permissible limit 25.0 NTU (Mandal, 2012). Before wastewater discharge turbidity was in desirable limit, then high amounts of suspended solids are discharged and increase turbidity to 34.5 NTU. However in couple of meters after discharge diffusion being high and rapid flow of water, turbidity is near desirable limit. Results of second lot show turbidity is mutable before dairy wastewater discharge, can be supposed that it is a natural source effect from algae or time to time municipal wastewater discharge.
Conclusion
Physico-chemical parameters of water pH, DO, ORP, NO3 - N, NH3 - N and turbidity show clearly that before discharge they were mostly within acceptable limit but river is polluted only as long as wastewater is being discharged. Results show a decrease of pH, DO, and ORP and an increase of turbidity, NO3 - N and NH3 - N. After discharge parameters slowly change towards normality. Comparison of result of a discharge day and next day before discharge show that except dairy wastewater there happen time to time municipal wastewater discharges in river. Rapid water flow enables fast diffusion and prevents pollutants concentration, odor and toxicity. In conclusion, even dairy wastewater and municipal discharge have negative effects in river, results are within maximum allowed limits from WHO and EU so can be concluded that river's water is not polluted.
References
[1] . Chapman, D. (1996). Water Quality Assessments - A Guide to Use of Biota, Sediments and Water in Environmental Monitoring - Second Edition, Chapman & Hall, Great Britain.
[2] . Omaka, O.N., Nwabue F.I., Itumoh E.J., Oroke E.C. and Igwe D.O. Physicochemical parameters and nutrients variations of streams and rivers in Abakaliki, Ebonyi State, Nigeria Global NEST Journal, Vol 16, No 1, pp 114-123, 2014.
[3] . Al-Samawi, A. A. A. and Al-Hussaini, S. N. H. The oxidation reduction potential distribution along Diyala river within Baghdad city. Mesop. Environ. j., 2016, Vol. 2, No.4, pp. 54-66.
[4] . Ewemoje, E, Ihuoma, S. Physicochemical Changes in the Quality of Surface Water due to Sewage Discharge in Ibadan, South-Western Nigeria, Energy and Environment Research; Vol. 4, No. 1; 2014.
[5] . Arifi, N. (2017). Nitrifikimi dhe denitrifikimi ne procesin e llumit aktiv (Punim Masteri).
[6] . Mandal, H., Das, A., Nanda, A., Study of Some Physicochemical Water Quality Parameters of Karola River, West Bengal - An Attempt to Estimate Pollution Status, International Journal of Environmental Protection, Aug. 2012, Vol. 2 Iss. 8, PP. 16-22.
