Risk assessment for chemical pollution of dairy effluents from a milk processing plant located in Bechar (Southwest of Algeria)

Milk and dairy products’ production lines generate pollution in the form of food waste. The management of this waste concerns professionals that fit the purpose of this study to assess the chemical risk of the raw liquid effluents that are discharged from a milk processing plant located in Bechar (Southwest of Algeria) by analyzing the main chemical indicator parameters of water pollution following official analytical methods. A total of ten samples were analyzed during the months of February, March and April of the year 2019. The obtained results were interpreted according to the regulatory requirements recommended by the Algerian standard related to threshold limit of physicochemical parameters’ values. The obtained results showed pollution signs revealed by high levels of the organic matters, expressed by significant means related to the following parameters: chemical oxygen demand (COD: 810.33 mg/L), 5 days-biochemical oxygen demand (BOD 5 : 797.91 mg/L), total suspended solids (TSS: 47.3 mg/L) and turbidity (174.014 NTU) exceeding those required by the national standard, except other physicochemical parameters, such as pH, conductivity, sulfate, nitrate and nitrite contents that did not exceed the threshold of acceptable values. Although these raw effluents present a high organic load expressed by average BOD 5 /COD ratio equal to 0.985, they constitute organic matters in a dissolved form (average value of the TSS/BOD 5 ratio = 0.076). Furthermore, The COD/BOD 5 ratio that had an average value equal to 1.015 underlines the biodegradability character of discharged dairy effluents. The high pollution levels which are aggravated by the lack of wastewater treatment can hurt the environment and the biological diversity and, therefore the humans' health. This requires an immediate intervention for a solution, where it is very important that proper wastewater treatment systems should be installed for the environment protection and for the ecological balance. Otherwise, it may constitute a risk to the public health on medium- to long-term by affecting the quality of the underground reservoir known as the main source of supply for the inhabitants of arid and semi-arid areas.