الفهرس 
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Abstract
The aim of the present study is carried out for enhancement the wet anaerobic digestion at concentration close to 10% of total solids to produce biogas form corncob as agriculture residues and cow manure though microwave and ultrasonic pretreatments with suspending bacterial growth in up flow digester then optimizing the construction and the operating parameter of anaerobic digestion process achieves the optimum biogas productivity related to optimum pretreatment and operation condition. The present study includes four main steps - The first one is to obtain the behaviors of the corncob and cow manure in a batch digestion process as attached bacterial growth on untreated mono and co-digestion then with microwave pretreatments. - The second is to construct three up flow units with two pretreatment units for each microwave and ultrasonic pretreatments and effortless devices for operating, control, measuring and recording the power consumed, condition of digestion and biogas productivity of mono digestion (corncob or cow manure) and co-digestion (corncob+ cow manure) that connects with pretreatment units and untreated. - The third is to determine the optimum pretreatments level without titration that may be concluded from the modified up flow digester in batch condition with regarding suspended growth to use in assessment such as best pretreatments level, and microscopic evaluate to each different pretreatments levels - The fourth is to perform and assess the normal up flow operating system at the optimal pretreatments level and untreated for best behavior of anaerobic digestion system. To achieve these stages, three group experiments were carried out using a corncob and cow manure in two digestion systems are mono and co-digestion, a laboratory hammer grinding mill machine was used for milling corncob and sieved to get particles less than 2.5 mm. Within a water path to attain a constant mesophilic temperature 40 ± 2 ˚C of PVC containers as the batch anaerobic digesters had been set and maintained for attached bacterial growth. Then design three the pilot scale up flow digesters, one with a microwave unit installed, another for control and the third with ultrasonic pretreatment unit installed, with the heat water jacket are tested in modified batch as suspended bacterial growth for assessing the two pretreatments at each experimental levels with mono( 100 % Corncob and 100% Cow manure) and co digestion (50 % Corncob + 50% Cow manure) system and in a normal continues conditions of modified up flow digester, the best pretreatments for both microwave and ultrasonic that were Presented by previously experiments which were performed, at Tractor and Farm Machinery Test and Research Station in Alexandria Governorate. The first stage of the experiments It was carried out as Preliminary experiments to aspect the contribute of the corncob and cow manure in untreated mono digestion and co-digestion system under batch digestion, also the its behavior under microwave pretreatment at the power of 294, 511 and 700 W and exposure time of 5, 10 and 15 minutes were applied and The microwave added energy (SE) from microwave pretreatment was determined as gained results of the first stage. The second stage of the experiments It was carried out to study the direct effect of pretreatment by microwave and ultrasonic for each corn cobs, cow manure and mixture of both at ratio 50:50 % on based of total solids (T.S), in modified up flow to work in modified up flow digester batch condition as suspended growth The following operational variables were included - Nine microwave added energy (SE) from microwave pretreatment at the power of 294, 511 and 700 W and exposure time of 5, 10 and 15 minutes - Nine ultrasonic added energy (SE) from ultrasonic pretreatment at the power of 50, 100 and 150 W and exposure time of 5, 10 and 15 minutes - Two digestion system mono and co-digestion. The gained results of both of the first and second stage may be summarized as following 1- Corncob as individual (mono) substrates was found to have some downsides that might lead to instability in the digester, less biogas production 2- The average biogas production rate was 0.195, 0.0144 and 0.205 m3/m3/day for untreated cow manure, corncob and co- digestion respectively, and an increase of 1.05 and1323.611% more than that achieved from mono digestion for cow manure and corncob respectively in attached growth. 3- The average biogas production rate was 0.365, 0.089 and 0.4 m3/m3/day for untreated cow manure, corncob and co- digestion respectively in suspended growth. 4- The influence of suspended growth of untreated batch in the modified up flow digester revaluated that increasing ratio 87.2,517 and95.122% for cow manure, corncob and co- digestion respectively more than that in untreated batch digestion as type of attached growth. 5- The effect of 294 W microwave pretreatment of cow manure the average biogas production rate was 0.354, 0.436 and 0.495 m3/m3/day for pretreatment applied M1, M2 and M3 with increasing ratio from the control 1.37, 19.45 and 35.62% respectively. And with corncob the average biogas production rate 0.092, 0.108 and 0.126 m3/m3/day and different with the control in ratio of increase 3.37, 15.73 and 41.57% for pretreatment applied M1, M2 and M3 respectively. Moreover the average biogas production rate 0.41, 0.515 and 0.545 m3/m3/day within ratio of 2.5, 28.75 and 36.25% where comparing with the control for pretreatment applied M1, M2 and M3 respectively in co- digestion, within an increase greater than 15.82 and 345.65 % for SE level M1 at comparing with cow manure and corncob respectively, 18.12 and 376.85% at M2, also 10.10 and 332.54%at M3. 6- The effect of 511 W microwave pretreatment, the average biogas production rate 0.367, 0.517 and 0.253 m3/m3/day and the comparing ratio with the control 0.55, 41.64 and -30.68 % for pretreatment applied M4, M5 and M6 respectively, and for corncob the average biogas production rate 0.093, 0.134 and 0.146 m3/m3/day for pretreatment applied M4, M5 and M6, the control has been compared with pretreatment that increasing gradually for 4.49, 50.56 and 64% respectively. Furthermore co-digestion present the average biogas production rate 0.43, 0.63 and 0.394 m3/m3/day, also comparing with the control were had ratio 7.5, 57.5 and -1.5% for pretreatment applied M4, M5 and M6 respectively, within an increase greater than 17.166 and 362.365 % for SE level M4 at comparing with cow manure and corncob respectively, 21.86 and 370.15% at M5, also 14.87 and 169.86 %at M6. 7- The results of 700 W microwave pretreatment, for cow manure the average biogas production rate 0.402, 0.343 and 0.227 m3/m3/day for pretreatment appliedM7, M8 and M9 respectively. Furthermore comparing to control were had ratio 10.14, -6.03 and -37.8% at the same respectively, and for corncob 0.115, 0.137 and 0.151 m3/m3/day for pretreatment practical M7, M8 and M9 respectively. Moreover comparing to control were had increasing ratio 29.21, 53.93 and 69.66% at the same respectively, and for co-digestion shown the average biogas production rate 0.49, 0.27 and 0.26 m3/m3/day for pretreatment applied M7, M8 and M9 with comparing ratio 22.5,-32.5 and -35% respectively, within an increase greater than 21.89 and 241.935 % for SE level M7 at comparing with cow manure and corncob respectively, 6.72 and 97.1% at M8, also 14.54 and 72.2 % at M9. 8- The 50 W ultrasonic pretreatment achieved the following results, cow manure the average biogas production rate 0.38, 0.40 and 0.41 m3/m3/day and ratio 3.29, 8.22 and 11.78% when comparing with the control for pretreatment applied U1, U2 and U3 respectively. Also corncob present the average biogas production rate 0.096, 0.097 and 0.097 m3/m3/day and the comparison ratio with the control 7.86, 8.99 and 8.99% for pretreatment applied U1, U2 and U3respectively.and for co-digestion The average biogas production rate ranged between 0.421, 0.457 and 0.461 m3/m3/day and comparing ratio 5.25, 14.25 and 15.25% for pretreatment applied U1, U2 and U3 respectively 9- The effect of 100 W ultrasonic pretreatment for cow manure the average biogas production rate 0.395, 0.538 and 0.359 m3/m3/day and ratio 8.22, 47.4 and -1.64% were compared with the control for pretreatment applied U4, U5 and U6 respectively, and for corncob the average biogas production rate was 0.094, 0.099 and 0.106 m3/m3/day with ratio of the comparison with the control 5.62, 11.24 and 19.10% for pretreatment applied U4, U5 and U6 respectively. For co-digestion the average biogas production rate 0.458, 0.594 and 0.384 m3/m3/day and comparison ratio with the control were recorded 14.5, 48.5 and -4% for pretreatment applied U4, U5 and U6 respectively. 10- The result of 150 W ultrasonic pretreatment for cow manure The average biogas production rate 0.41, 0.36 and 0.32 m3/m3/day for pretreatment applied U7, U8 and U9 respectively, and ratio 11.77, -1.92 and -11.51 as difference with the control. And for corncob the average biogas production rate 0.098, 0.106 and 0.115 m3/m3/day with ratio 10.11, 19.10and 29.21% for pretreatment utilized U7, U8 and U9 respectively when comparing with the control. For co-digestion the average biogas production rate 0.461, 0.384 and 0.204 m3/m3/day for pretreatment applied U7, U8 and U9 with comparing ratio 15.25, -4 and 49% respectively. 11- Microscopic analyzes for the surface morphology as structures and particle size were don for the control and the SE levels in microwave and ultrasonic pretreatment with co-substance (50% corncob + 50% cow manure) at using scale 50 μm and 100 μm, Findings of this study indicate that increasing in SE level and value for microwave pretreatment led to increase in disintegration of cell wall and disruption morphology.as well as ultrasonic. The final stage of the experiments the best pretreatments for both microwave and ultrasonic that were shown by the experiments were performed on the modified up flow which was worked in the batch system and with co- digestion type that is the more efficient digestion type has been presented in The second stage of the experiments. The following operational variables were included The SE levels are M5 and U5 comparing with the control at 5, 10 and 15 days retention time for cumulative biogas production , biogas productivity over T.S added (m3/kg T.S add/day) and biogas production rate (m3/ m3 /day) The gained results of the final stage may be summarized as following 1- The average cumulative biogas production were at different retention times 5, 10 and 15 days were 13.51, 37.53 and 47.77 l/day respectively, for untreated co-substance C, the influence of microwave pretreatment M5 on the average cumulative biogas production, as it was recorded 19.22, 49.82and 61.65 l/day for 5, 10 and 15 days retention tie respectively, and ultrasonic pretreatment Co- digestion U5 highlighted 18.4, 49.2and 62.82 l/day for 5, 10 and 15 retention time respectively. 2- Decreasing in the biogas productivity with increasing added total solids, the average values of biogas productivity (m3/kg T.S add/day) 0.0263, 0.0727 and 0.0973 for retention times 5, 10, and 15 days with for untreated co-substance C, with microwave pretreatment M5 are recorded the average values of 0.0353, 0.099 and 0.13 for retention times 5, 10, and 15 days and ultrasonic pretreatment U5 on biogas productivity average values of 0.033, 0.097 and 0.128 (m3/kg T.S add/day) for retention times 5, 10, and 15 days respectively. 3- The average biogas production rate (m3/m3/day) has increased by increasing retention time from 5 to 10 days. The most remarkable result to emerge from the data is that, the average biogas production rate was decreased with increasing retention time from 10 to 15 days, for untreated co-substance C noted 0.418, 0.5784 and 0.5133 (m3/m3/day) for 5, 10 and 15 days respectively, average biogas production rate with microwave pretreatment M5 (m3/m3/day) was highlighted with values 0.561, 0.791and 0.685 (m3/m3/day) for 5, 10 and 15 days and ultrasonic pretreatment U5 was revealed an effect on average biogas production rate which o.525, 0.773 and 0.673(m3/m3/day) for 5, 10 and 15 days respectively. 4- The averages cumulative biogas productions for 5 days retention times were 13.508, 18.375 and 19.23 l/day for untreated (control), ultrasonic pretreatment and microwave pretreatment respectively, also could be seen increasing about 36.03% and 42.36% for ultrasonic (U5) and microwave (M5) pretreatment respectively The averages cumulative biogas productions for 10 days retention times which have 37.531, 49.24 and 49.82 for untreated (control), ultrasonic pretreatment and microwave pretreatment respectively, furthermore 31.2% and 32.74% were increased when comparing with the control for ultrasonic(U5) and microwave(M5) pretreatment respectively, and the cumulative biogas production and 15 days retention times with averages 47.66, 62.82 and 61.64 l/day for untreated (control), ultrasonic pretreatment and microwave pretreatment respectively, with the ratio of increasing from the control was been about 31.81% and 29.33% for ultrasonic(U5) and microwave(M5) pretreatments respectively. 5- for 5 days retention times The averages biogas productivity were 0.0263 0.0330 and 0.0353 m3/kg T.S add/day at untreated (control), ultrasonic(U5) pretreatment and microwave(M5) pretreatment respectively, with 25.475% and 34.22% was increased for ultrasonic and microwave pretreatment at comparing with the control. Moreover increasing ratio 6.97 % for microwave pretreated than ultrasonic pretreated, for 10 days the biogas productivity over T.S added (m3/kg T.S add/day) with averages 0.0727, 0.0971 and 0.09943 m3/kg T.S add/day for untreated (control), ultrasonic (U5) pretreatment and microwave (M5) pretreatment respectively, and when were compared with control can observed an increasing ratio 33.56% and 36.77% for ultrasonic and microwave pretreatment respectively, and for 15 days the values 0.0973, 0.1276 and 0.1297 m3/kg T.S add/day ai as averages biogas productivity for untreated (control), ultrasonic pretreatment (U5) and microwave(M5) pretreatment respectively. More than that 31.14% and 33.3% was increased at comparing with the control for ultrasonic and micro wave respectively. 6- The average biogas production rates with 5 days retention times were 0.418, 0.525 and 0.561 m3/m3/day for control , ultrasonic and microwave pretreatment respectively, with the ratio of increasing 25.6% and 34.2 % for U5 and M5 respectively at comparing with the control for 10 days The average biogas production rates were 0.58, 0.773 and 0.791 m3/ m3/day for control, ultra sonic (U5) and microwave (M5) pretreatment respectively, and the increasing ratio about 33.28% and 36.4 % for U5 and M5 respectively when were compared with the control, and for 15 days the average biogas production rates were 0.513, 0.673 and 0.685 m3/ m3/day for control, ultra sonic (U5) and microwave (M5) pretreatment respectively, and the increasing ratio when it were comparing with the control has 31.2% and 33.52 % for U5 and M5 respectively. 7- The different of power consumption in pretreatment, when comparing the SE levels M5 and U5, could be aspect increasing M5 with the ratio of 84.4% (1.8414 times U5). Even though these results the highest value methane content has obtained with 10 days and microwave pretreatment (M5) while the control (C) trend to be lowest value. 8- The maximum net energy gained from micro wave pretreatment (M5) then ultrasonic pretreatment (U5) with 10 days retention times and the total energy consumed present about 9.2% and 8.8% from the energy production respectively, while the lowest energy gained from the control with 5 days retention time and energy consumption about 16.11%.