Self-Purification and Assimilation Power of the River Yamuna at Agra

Transcription

1 Self-Purification and Assimilation Power of the River Yamuna at Agra Alka Yadav 1, R.P. Singh 1, and R. Upadhyay 2 1 Department of Chemistry, St. John s College, Agra , India 2 Assistant Scientific Officer, U.P. Pollution Control Board, Bareilly, India. Abstract The paper discusses the Self-Purification and Assimilation power of the river Yamuna at Agra over a period of one year. It appears from the results that the Self-Purification power of the river is very small in comparison to other rivers. Keywords- Self Purification Power, Abiotic and Biotic Limnological Factors, Agra 1 Introduction Introduction of excessive quantities of waste material can upset the cycle by causing rapid bacterial growth and resulting depletion of dissolved oxygen in stream. Polluted waters are characterized by very large numbers of relatively few species. As the excess organic matter is stabilized the normal cycle is reestablished in a process known as self - purification. Water quality standards are often based upon maintenance of some minimum dissolved oxygen concentration protects the natural cycle in the scream while taking advantage of its natural assimilative capacity. When oxidizable organic matters such as sewage/sullage are discharges in the river system they get decomposed due to microorganisms, a process which creates biochemical oxygen demand (BOD) in the river system. This reduces dissolved oxygen (DO) already in river water. This is an important parameter that enables to judge the quality of water. Similarly the organic matter which is biochemically nonoxidizable, also creates chemical oxygen demand (COD) normally in a healthy river system. There is a reserve of DO to support biochemical oxidation. In absence of adequate DO, an aerobic breakdown of organic matter leads to septic conditions and foul smell which changes the character of the river systems. The relationship between DO-BOD in fact would be one of the important leads to self-purification ability of a river system. Based on the available data, the central Pollution Control Board (CPCB, 1984)[1] has come to the conclusion that for pollution at a point in the Ganga, it should not take more than a day, or say 100 km downstream, to be removed through the prevailing self-purification capacity of the river. However, that is not so because the river system receives apart from the point loads, a Significant quantum of distributed BOD load in its course from Kanpur to Varanasi and perhaps throughout its entire length due to organic pollution load brought down by tributaries, local contributions, surface runoffs, etc. This is an important aspect to take note of Alka Yadav, R.P. Singh, and R. Upadhyay

2 The self-purification of a river is complicated process which depends on both abiotic and biotic limnological factors. The self-purification capacity of some polluted rivers including the Ganga river in Uttar Pradesh (Saxena et al. 1966[2]; Ajmal et al. 1982)[3]; The Khan river at Indore (Buluse et al. 1967)[4]; The Kalinadi in Uttar Pradesh (Verma and Dalela, 1975)[5]; Ajmal et al.[6]. The Vaigai river in South India (Mahadevan and Krishnaswamy, 1986)[7], flowing municipal water at Dharwad (Patil and Rodgi, 1985)[8] and the river Kali in Karnataka (Hosett and Birsal, 1989)[9] have already been studied. In the present study the assessment of the self-purification was made by comparing certain water quality parameters viz., dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, total dissolved solids, nitrate and phosphate, at various 4 stations of the river. 2 Material And Methods A. STUDY AREA: 12 km to downstream (Taj). B. SELECTION OF SITES: 4 Sampling stations were selected to assessment of self-purification capacity of the river Yamuna. Each station was at a distance of 4 km from each other. I station was down stream (Taj). C. FREQUENCY OF SAMPLING: Sampling was done at well planned monthly intervals. D. THE COLLECTION OF THE SAMPLES: The water samples from river were collected from all the sampling stations at well planned monthly intervals. The monthly samples of surface water were collected in the first week of every month in the early hours of the day, i.e., between 6 to 10 a.m. Samples from the river water collected in two litre precleaned plastic bottles in duplicate, one for physico-chemical analysis and other was acidified with concentrated HNO3 for the analysis of heavy metals. Two separate glass bottles (300 ml) were filled with water, one for the estimation of di ssolved oxygen (DO) and other for the determination of biochemical oxygen demand (BOD) as referred by Golterman et al.[14]. Samples for coliform detection were collected in sterilized glass bottles and preserved in ice (Goel and Trivedi)[15]. Water temperature, was determined at the sampling stations while other parameters were analysed in the laboratory. E. ANALYSIS: The collected samples were analysed in the laboratory as per Standard Methods [16]. 3 Results The concentrations of above mentioned parameters are shown in Table 1 to 6. The percent change in these parameters was determined by using annual average concentration (Table 7). It was found that out of these parameters DO was improved by 7.96% whereas BOD, COD, TSD, Nitrate and phosphate were reduced by 1.86%, 4.06%, 2.64%, 4.93% and 2.39% respectively from station I to II. At station III DO was increased by 10.5% and BOD, COD, TDS, Nitrate and phosphate were decreased by 1.08%, 5.25%, 5.68%. 7.35% and 2.83% respectively. Similarly from station III to IV DO was found increased by an extent of 8.33 but reduction in BOD by 5.10%, in COD by 6.20%, in TDS by 6.7%, in Nitrates by 8.4%, and in phosphate by 4.85 (Table 7) Alka Yadav, R.P. Singh, and R. Upadhyay

3 1450 Alka Yadav, R.P. Singh, and R. Upadhyay

4 1451 Alka Yadav, R.P. Singh, and R. Upadhyay

5 1452 Alka Yadav, R.P. Singh, and R. Upadhyay

6 1453 Alka Yadav, R.P. Singh, and R. Upadhyay

7 4 DISCUSSION In sewage and polluted waters, natural agencies operate in order to render it stable and bring back to innocuous state. The self-purification in polluted rivers is brought about by distance of flow (Adeney, 1928)[10], fast flow of the river (Klein, 1957)[11], oxygenation (Phelpss, 1960)[12], agitation and turbulence of water (Pilai, et al., 1960)[13], etc.. The self-purification capacity of Ganga river as studied by Ajmal et al. (1982)[3] was due to fast flow and uptake of oxygen from surface. Patil and Rodgi (1985)[8] have observed that the flowing sewage in the channel became clear and was oxidised to a considerable degree after its flow over a distance of 6 km as a result of reduction in nutrients and BOD and increase in ph and dissolved oxygen. The lack of self-purification capacity in the River Vaigai with respect to total solid can be attributed to its basic difference in the habitat structure (Mahadevan and Krishnaswamy, 1986)[7]. In the present study the Yamuna river showed a tendency of self-purification as it flows far from the Agra city. It was found that oxygenation was progressively enhanced while BOD, COD, TDS, nitrate and phosphate gradually reduced from station I to IV. The increase in DO from station I to IV was maybe due to algal growth and photosynthesis. BOD & COD are inversely relation with DO. The gradual decrease in TDS, and phosphates towards the last point may be due to the seepage into the sediment. The above observation confirmed gradual self-purification activity from station I to II, II to III and from station III to IV in the river. When above parameters at Station I were compared with Station IV, it was very much evident that dissolved oxygen was improved by 29.35% BOD, COD, TDS, Nitrate and Phosphate were however, reduced 7.88%, 14.74%, 14.21%, 19.34% and 9.76% respectively. 5 CONCLUSION On account of above investigation, it may be stated that the self-purification process is apparent in the river after flowing through 12 km but it is very small in comparison to other rivers. The above data clearly reveals that self-purification in the river Yamuna at Agra is not high which may be attributed due to lower velocity & flow and high organic load on the stream. References [1] CBPCWP, Basin, Sub-basin, inventory of Water Pollution: The Ganga basic Part I and Part II, Central Board for the Prevention and control of Water Pollution, New Delhi.,(1984). [2] Saxena, K.L.; Chakrabarty, R.N.; Khan, A.O., Chatopadhya, S.N. and Harish Chandra; Environ. Hlth., 8, , (1966). [3] Ajmal, M; Nomani, A.A. and Khan, M.A.; IAWPC Tech, Annual, 9, , (1982) [4] Bulusu, K.R.; Arora, H.C. and Aboo, K.M.; Environ. Hlth. 8, , (1967). [5] Verma, S.R. and Dalela, R.C.; Hydrobiol, 3(3): , (1975). [6] Ajmal, M.; Raziuddin and Khan, A.U.; IAWPC Tech. Annul. 12, , (1985). [7] Mahadevan, A, and Krishnaswamy, S.; Poll, Res., 5(2), 69-72, (1986). [8] Patil, H.S. and Rodgi, S.S.; pp Incurrent Pollution Researches in India. (R.K. Trivedyand P.K. Goel, eds.). Environmental Publications, Karad, (1985). [9] Hoselti, B.B. and Birasal, N.R.; J. Nat. Con., 1(2), , (1989). [10] Adeney, W.E.; The principles and practice of the dilution method of sewage disposal. Cambridge Univ. Press., (1928). [11] Klein, L; Aspects of river pollution. Butter-Worth Scientific Publication, London., (1957). [12] Phelps, B.E.; Stream sanitation, New York, John Wiley and Sons, Inc., London, (1960). [13] Pillai, S.C.; Mohanrao, G.J.; Prabhakararao, A.V.S.; Sastry, C.A.; Subrahmanyam, P.V.R. and Natarajan, C.V.; Curr. Sci. 29, , (1960.) [14] Golterman, H.L.; Physiological Limnology, Elesvier, New York, (1975). [15] Trivedy, R.K. and Goel, P.K.; Environ. Puld. Karad (India), (1986). [16] APHA; Methods for Examination of Water and Wastewater (14 Edn.) American Publ. Hlth. Assoc., New York (1976.) 1454 Alka Yadav, R.P. Singh, and R. Upadhyay