QUALITY OF RICE MILL WASTE WATER AND ITS IMPACT ON GROWTH AND NUTRIENT CONTENT OF RICE PLANT

Abstract

An investigation was carried out to assess the suitability for agricultural purpose of 30 rice mill wastewater samples collected from different locations in Dinajpur district of Bangladesh. Analyses included pH, EC, TDS (Total dissolved solids), cations and anions (Ca2+, Mg2+, Na+ , K+ , Cu2+, Mn2+, Fe3+, HCO3 - , and Cl- ). Several computed variables such as SAR (Sodium adsorption ratio), hardness (HT), permeability index (PI), and Kelly‘s ratio to evaluate the suitability of wastewater for specific uses. The wastewater were found acidic (pH varied from 5.33 to 6.77) that are suitable for rice seedlings. Wastewater samples contained Ca2+, K+ and Na+ as the dominant cations and HCO3 - and Cl- were the dominant anions. According to EC value, the samples were excellent and good for germination purposes. The SAR value of all waste water samples were excellent classes. Maximum samples were within hard regarding hardness. Based on, (HCO3 - and Cl- ) of rice mills waste water were found to be 'safe' limit for germination. The correlation coefficient were positive of among pH, EC, TDS, Mg2+, K+ , HT, Ca2+ , Mg2+, K+ , Na+ and HCO3 - reproduced that the quality of the free soil solution may indicate the distribution of Na+ in the absorbed phase. On the other hand, the correlation coefficient for pH-Temp, pH-P, EC-Temp, Mg-P, P-Fe, Cu-F indicated that the increase of one parameter will result in the decrease of the aforementioned parameters. After tested the waste water, further conducted laboratory experiment to determine the effect of different waste water on germination, seedling growth and mineral composition of different rice verities. The results revealed that the highest germination (98%, 98% and 100%) was found in BRRI 28, BRRI 58 and Kataribhog, respectively with the treatments of T4 (Waste water of Birgonj rice mill), T4 (Waste water of Birgonj rice mill) and T1 (Waste water of Dinajpur sadar rice mill). The highest shoot and root weight of seedlings were found in wastewater treatments in comparison to normal water. The results indicated that the waste water enhanced the shoot length, root length and nutrient content in rice plant. However, overall view of rice mill waste water were suitable for seedling growth and development after proper management.