Removal performance for thermotolerant coliforms and fecal streptococci from dairy effluents by Kenadsa’s natural green clay (Bechar-Algeria) in a fixed-bed column

This present work is a part of the liquid discharges treatment topic by studying the removal performance for thermotolerant coliforms (FC) and fecal streptococci (F.Strep) by a local natural light green clay from Kenadsa (Bechar-Algeria) under continuous adsorption processes in a fixed-bed column. The study estimated the clay adsorbing efficiency by the adsorption technique for bacteria contaminating the dairy effluent by determining the bacterial load before and after treatment. The mean log counts per 100 ml for FC and F.Strep were assessed by MPN method on liquid medium. The clay material characterizations were made through X-ray diffraction, X fluorescence spectrometry and Fourier transform infrared spectroscopy analysis. Besides, some parameters were estimated such as the breakthrough time tb (clay filter breakdown); the amount of the contaminating bacteria that was removed at the breakthrough time Xb and the exhaustion of disinfection capacity Xe; the total amount of contaminating bacteria flowing through the column Xtotal; and the total removal efficiency (Y). According to the XRD, XRF and FTIR results, the predominant mineral constituents were silicon dioxide, aluminum oxide, ferric oxide and magnesium oxide with rates of 59,44; 18,09; 7,79; and 3,87%, respectively, and hence, their classification among non-swelling clay minerals, illite is the major mineral group of this material. The results of the bacteriological analysis of raw dairy effluents showed an average bacterial load of 3,88 Log10 and 4,1 Log10 CFU/100 mL for FC and F.Strep, respectively, exceeding the thresholds set by the national and the international regulations. The results of the dairy effluents treated by the tested material have shown that the used clay has a relatively high adsorption property for the clay fixed-bed system (3 cm of bed height), expressed by a total removed efficiency Y (%) of FC and F.Strep used to evaluate the column performance ranging from 55 to 84%. It gives a higher log removal for FC and F.Strep (0.98–1.65 Log10) reported from the first adsorption process, and a breakthrough time ranged from 100 to 250 min, which was inversely proportional to the initial bacterial load of discharges and also linked to the nature of the bacterial contaminants. When the breakthrough occurs earlier, the column service life will be shortened. For the studied parameters, the results of treated effluent complied with national and WHO regulations for unrestricted agricultural irrigation, otherwise, as authorized effluents to be discharged into nature without risks. These preliminary results are very promising at laboratory scale as an innovative green technology, treatment method respecting the environment and opens up prospects for the future, where the modification or the optimization of operating conditions such as the bed height of the fixed bed for adsorption, the volumetric flow rate or the clay structure like the particle size distribution of the adsorbents, known as one of the adsorbent classes endowed with an antimicrobial property, can improve the column performance, and further, the removal or even more the disinfection process by adsorption method.

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 (BOD5: 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 BOD5/COD ratio equal to 0.985, they constitute organic matters in a dissolved form (average value of the TSS/BOD5 ratio = 0.076). Furthermore, The COD/BOD5 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.

Addition of hydrogen peroxide in electrocoagulation of dairy liquids

Standing out on the national and world scene as an important economic and social activity, the dairy products industries are characterized by their high polluting potential, especially due to the liquid effluents generated. In this context, the present work aims to study the application of the electrocoagulation process applied associatively with hydrogen peroxide (H2O2) in the treatment of dairy effluents using iron electrodes. Effluent treatments were carried out with the electrocoagulation process in a continuous flow reactor. For the method using electrocoagulation, the removal efficiencies in relation to color, turbidity, total organic carbon, chemical oxygen demand and nitrogen removal were 97.2%, 97.0%, 77.5%, 63.3% and 92.2%, respectively. The addition of H2O2 to the beginning of electrocoagulation process in the treatment of dairy effluents did not contribute to an increase in the efficiency of removing organic matter. When applied after an electrocoagulation step, it demonstrated to be efficient, reaching COD removals of 97.7%. Therefore, the electrocoagulation demonstrated to be a technically viable alternative for the treatment of dairy effluent.

Waste Water Characterisation of Milk Processing Industry

Contamination acknowledged by present day and dairy effluents is a genuine pressure all through the world (Braio and Granhem, 2007).Of every single mechanical improvement, the sustenance area has apparently the most astounding utilization of water and is perhaps the best maker of profluent per unit of creation regardless of conveying, other than to make a tremendous volume of seepage in like manner treatment (Ramjeawon, 2000).The dairy industry is an example of this segment. Dairy is an industry where milk is prepared and particular milk things are made. Dairy, in which the cleaning storerooms, tanks, heat exchangers, homogenizers, channels and other apparatus, prompts a lot of gushing with a high normal weight. This ordinary weight is commonly included by mil(raw material and dairy things), inorganic salts, synthetic substances, sanitizers utilized for washing mirroring a profluent with a great deal of mix oxygen request (COD), biochemical oxygen request (BOD), oils and oil, nitrogen and phosphorus than the fated farthest compasses of BIS.