الفهرس 
INTRODUCTION AND AIM OF THE WORKOnly 14 pages are availabe for public view
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Abstract
Industrial wastewaters are effluents generated from human activates that are affiliated with raw materials processing and manufacturing. Its disposal has become an important issue due to its adverse impact on aquatic life and the surrounding environment. Industrial wastewater characteristics differ according to the type of raw materials and the type of industrial process used. Due to the negative impacts of untreated industrial wastewater discharge, regulations are becoming stricter and the treatment of the industrial effluents is nowadays obligatory.
Lubricating grease manufacturing was chosen as a one of those industries whose wastewater effluent is causing a problem for the public sewerage system and the wastewater treatment plant. Lubricating grease is an essential requirement for the industrial sector to enhance durability, dependability, and efficiency of equipment. It is a solid or semi-solid product. It contains around 90% of additives, base oil and soap or other thickening agents. Type of thickeners is considered an important factor that determines grease characteristics. These thickeners are classified into groups according to their nature and interaction with the dispersion medium. These groups include polymorphic, non-polymorphic and heat resistant organic and inorganic thickeners.
Grease manufacturing process itself results in small amount of wastewater highly concentrated with COD. Generally, the most waste loading occurs when the process units are washed as this generates oil and soap to be discharged in sewer pipes as oily wastewater. In case of calcium base soap grease production; the conversion of sodium base soap to a calcium base soap is a process which generates a relatively small wastewater quantity has high concentrations of sodium chloride and emulsified oils.
According to a recent research carried out in 2018 on treatment of wastewater resulting from grease factories. Among the applied treatment methods, anaerobic treatment enhanced with marine fouling reported the maximum organic matter removal from wastewater compared with other methods “coagulation followed by sedimentation and adsorption using CSMBS & FSMBS”. However, this method was not studied in depth especially use of mixing and heating.
The aim of this study was focusing on the anaerobic treatment of wastewater enhanced with marine, mixing and heating, as well as a study of the biogas resulting from the anaerobic treatment process. Finally, cost-effective analysis of the different treatment scenarios was undertaking.
Three treatment stages were examined in terms of their efficiency in COD removal. The first one was study the effect of mixing. Second, study the effect of heating. The last treatment stage was the study of effect of mixing and heating together on COD removal. Also, the amount of biogas resulting from the treatment process was measured, under the different treatment conditions “with and without heating and mixing”. Three bench scale reactors for anaerobic treatment of wastewater were prepared with mixers and heaters and fitted in the lab of Environmental Health Department at the High Institute of Public Health. The fourth reactor was prepared without mixers and heaters.
Three mixing speeds (12, 30, 60 RPM) were used to study the effect of mixing on the treatment. According to the results, it is worth mentioning to state that mixing of wastewater during the anaerobic treatment process with marine fouling reduced the required time of treatment from 1 – 4 days and increased the COD removal percentage from 0.7% to 4.4% compared to the results of treatment without mixing. The best mixing speed give maximum enhancement according to COD removal and stability time of treatment was 60 RPM.
Three heating temperatures (30, 45, 60 ºC) were used to study the effect of heating on the treatment. According to the results, it is worth mentioning to state that heating of wastewater at 30 ºC, 45 ºC and 60 ºC during the anaerobic treatment process with marine fouling reduced the required time of treatment between 1 to 4 days and increased the COD removal percentage from 1.3 % to 9 %. Based on the above reported results, the best heating temperature give maximum enhancement according to COD removal and stability time of treatment was 60 oC. On the other hand, when comparison made between mixing effect and heating effect on the treatment, it is worth mentioning to state that heating was better than mixing in terms of COD removal percentage, while both (mixing and heating separately) were almost the same in terms of to stability time.
Last stage was using three combinations of mixing and heating to study the effect of mixing and heating together on the treatment. According to the results, it is worth mentioning to state that the best combination of mixing and heating options give maximum enhancement according to COD removal (14.8%) and stability time (4-9 days) of treatment was 60 RPM with 60 ° C.
One of the aims of this study was collect and measure the biogas generated from treatment. Six experiments were conducted, three experiments were carried out without mixing or heating to measure the biogas yielded, and three more experiments were conducted to determine the effects of heating and mixing on gas production. The results of the experiments were that the treatment of one liter of wastewater produces about 12.5 ml of biogas in about nine days, while under the influence of mixing and heating, the amount of gas produced reaches about 27 ml/L in approximately six days. The results indicated to the amount of biogas produced by the anaerobic treatment process with heating and mixing was significantly increased (2.1 times) compared with anaerobic treatment without heating and mixing. Also, the number of days of biogas production was significantly reduced by 45% when heating and mixing is used during the anaerobic treatment process. Concentration of methane in produced biogas was measured, it was 41% of the biogas volume.The cost effectiveness analysis was performed on all the results of the treatment methods in this study. The result of cost effectiveness analysis for all treatment methods of the study can be summarized in that the best conditions were when using mixing and heating together at 60 RPM with 60 ° C with using biogas for heating.5.2. Conclusion
Based on the findings of the study, the following can be concluded:• Conventional anaerobic decomposition of wastewater generated from grease manufacturing process was very weak due to the high salinity concentrations, which adversely affect the growth microorganisms required for the anaerobic treatment.• When anaerobic decomposition was enhanced by 75 g/l dose of ship fouling, it was capable to remove about 75% of COD in 14 days.
• Anaerobic decomposition enhanced by marine fouling with mixing at 60 RPM, was capable to remove about 80% of COD in 10 days.• Anaerobic decomposition enhanced by marine fouling with heating at 60 ° C, was capable to remove about 82.7% of COD in 11 days.• Anaerobic decomposition enhanced by marine fouling with mixing at 60 RPM and heating at 60 ° C, was capable to remove about 89% of COD in 6.6 days.• The results of anaerobic treatment will improve the COD removal if mixing is used to 5%.• The results of anaerobic treatment will improve the COD removal if heating is used to 7.7%.• The results of anaerobic treatment will improve the COD removal if mixing and heating is used to 14%.• Anaerobic treatment enhanced with marine fouling for one liter generated 4.3 ml/day of biogas which can be used in heating to reduce the treatment cost.
• The biogas produced from anaerobic treatment enhanced with marine fouling contains CH4 with percentage reached to 41%. • The amount of biogas produced was positively affected by heating and mixing although the treatment stability time was reduced.
• Anaerobic treatment with mixing and heating was better because the process takes place in fewer days, which reduces energy consumption based on the results of CEA.
5.3. Recommendations Based on the results of the study, the following was recommended:
• Undertake more research on effect of mixing on anaerobic digestion enhanced by marine fouling by using different designs of mixers to obtain the optimum design.• Study the effect mixing, heating individually on biogas production. • Physical, chemical and biological analysis of marine fouling are required for deep understanding of the reasons led to its enhancement of the anaerobic treatment of wastewater.• Isolation of the anaerobic micro-organisms present in the marine fouling to study their individual effects on anaerobic treatment of wastewater enhancement.• Undertake more research on the use of marine fouling for anaerobic treatment enhancement in other strong industrial wastewaters treatment.• Undertake more research on the use of marine fouling for anaerobic treatment enhancement in anaerobic sludge digestion•Undertake more research on the use of marine fouling for anaerobic treatment enhancement in anaerobic digestion leachate of solid waste landfill.Macro scale applications are required for accurate assessment of the use of marine fouling for anaerobic treatment enhancement.• Aeration of the treated wastewater using anaerobic treatment is recommended to study the possibility of the remained COD removal after anaerobic treatment.•More chemical analysis for the treated wastewater is recommended to know the COD fractions “organic and inorganic”.