ANALYSIS OF SOME SELECTED PARAMETERS OF DASHEN BREWERY SEWAGE SLUDGE FOR AGRICULTURAL PRODUCTIVITY

Abstract

Brewery sludge is produced during the beer production in different process steps and finally collected in the form of solid through waste water treatment process. Dashen brewer Share Company removes this sludge without measuring the content of nutritional and heavy metal elements in the sludge. The main objective of this study was to determine the content of nutritional elements and the concentration of heavy metals in sludge samples. In this work, three samples were collected in Dashen Brewery Share Company on the months of end of September 2019, December 2019 and March 2020. A total of 2 kg of sludge sample was collected in each sampling months at the solid waste removal and collecting area. From the collected samples 0.5 g of sludge samples was taken from each sampling months and digested by hot plate using 2 mL of HNO3 and 5 mL HClO4. The content of available phosphorus, total nitrogen and heavy metals were determined using Olsen, Kjeldahl and flame atomic absorption spectroscopy (FAAS), respectively. The accuracy of the method for heavy metal measurement was assessed by spiking sludge samples with known amounts of standard metals, and examining recovery. A good percentage recovery was obtained and percentage recovery was ranging from 85.3 to 113.7 %. This investigation helped to conclude that the acceptable level of heavy metals present in the Brewery sludge of the study area has no negative impact on the living organisms. The elemental contents found in all sample of the brewery sludge were higher in concentration(mg/g) for Zn(0.364±0.012-0.384±0.006), Cr(0.087±0.021- 0.099±0.021) and Cu (0.05±0.003-0.056±0.004) whereas for Ni (0.016±0.006-0.018±0.004) and Cd (0.004±0.001-0.0048±0.001) metal were slightly lower in values. Pb was not detected due to its value was below the detection limit. The concentration of total nitrogen was 4.21±0.21-4.25±0.11% and 0.175±0.0006-0.176±0.0007 % was the result obtained for available phosphorus