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
