Comparative evaluation of biogas production from Poultry droppings, Cow dung and Lemon grass

There is urgent need for proper waste management and development of alternate energy using wastes in developing countries. Optimal digestion mixture of substrates ensures that waste products of animals, industries etc. are optimized. This study was designed to determine the optimal mixing ratio of cow dung and poultry droppings in biogas production under tropical condition. The mixing ratio used were 100:0, 75:25, 50:50, 25:75 and 0:100 for cow dung (CD) and poultry droppings (PYD), respectively. The fermentation was carried out in five 30 L digesters locally fabricated. The biogas yields obtained in the work for the cow dung and poultry dropping mixture were in the order of   25% CD + 75% PYD >  100% CD + 00% PYD > 50% CD + 50% PYD > 00% CD + 100% PYD > 75% CD + 25% PYD. The kinetics of anaerobic digestion process of the various digestion mixtures was successfully evaluated with modified first order model equation; the result shows that poultry dropping (alone) has the highest short term biodegradability index of 2.4 while the 50% CD+50% PYD digester has the highest removal rate of the biodegradable fractions (k) of -0.199 among all the substrates. Thus,  optimum mixing ratio for cow dung and poultry dropping suggested by the study is 25% CD + 75% PYD mixing ratio which gave 16.35 L/total mass of slurry (TMS) within the period under study.   Key words: Waste management, energy, cow dung, poultry droppings, biogas.

Field studies were conducted at the Teaching and Research Farm, Federal University Wukari, to evaluate the bacterial population and selected physicochemical properties of compost in Wukari, Taraba State, Nigeria. Eight compost treatments were tested: GCP (Gmelina leaf + cow dung + poultry droppings), SGCP (Sawdust + Gmelina leaf + cow dung + poultry droppings), RGCP (Rice husk + Gmelina leaf + cow dung + poultry droppings), MGCP (Maize stalks + Gmelina leaf + cow dung + poultry droppings), GCPU (Gmelina leaf + cow dung + poultry droppings + urea), SGCPU (Sawdust + Gmelina leaf + cow dung + poultry droppings + urea), RGCPU (Rice husk + Gmelina leaf + cow dung + poultry droppings + urea), and MGCPU (Maize stalks + Gmelina leaf + cow dung + poultry droppings + urea). Wood ash, water, and topsoil were added to all treatments. Compost pits (1 m³) were prepared for each treatment, replicated three times in a Randomized Complete Block Design (RCBD). Turning, bacterial enumeration, and temperature recordings were conducted monthly. Results revealed significant variation in bacterial populations, with MGCPU recording the highest counts. Compost temperatures remained below 40°C across all stages, indicating decomposition occurred predominantly within the mesophilic range. Total nitrogen (TN) content varied significantly, with RGCPU yielding the highest TN value. Available phosphorus was moderate across treatments, while potassium levels showed no significant difference. Overall, RGCPU and MGCPU outperformed other treatments in terms of microbial activity and nutrient content. Thus, RGCPU is recommended as the most suitable composting treatment for the study area.

As part of the effort in developing alternative protein ingredient to reduce the costs of feed associated with livestock production, maggotries were constructed to compare the yield and chemical composition of maggot meal produced from three substrates – poultry dropping, pig, and cattle dung. 150 kg each of poultry droppings, pig, and cattle dung were assigned into three treatments and further divided into 3 replicates of 50 kg each. Three liters of fresh cattle blood (attractant) was added per replicate without stirring. The housefly (Musca domestica) shed its eggs on the blood in the course of feeding which later developed into maggot. The collection of data started 5 days after the emergence of maggots on the substrates. 4.91 kg of maggot was obtained from poultry dropping, 3.53 kg from pig dung, and 0.95 kg from cattle dung. The chemical composition showed that maggot meal produced from poultry dropping substrate is higher in crude protein and crude fat (42.53% and 7.38%) than that of pig dung (40.78% and 6.08%) and cattle dung (41.69% and 6.29%) respectively. The amino acids composition of maggot meal produced from poultry dropping (lysine 0.89%, methionine 0.67%, and tryptophan 0.74%) were also comparably higher than that from pig dung (lysine 0.57%, methionine 0.38% and tryptophan 0.51%) and cattle dung (lysine 0.76%, methionine 0.51 kg and tryptophan 0.68%). However, the microbial load and mineral composition were observed to be higher in maggot meal produced from pig dung than those obtained from poultry dropping and cattle dung. Poultry dropping is of higher yield in maggot meal production, crude protein, crude fat, amino acid composition, and lower microbial load than pig and cattle dung. Although the maggot meals obtained from the three substrates can be used as an alternative protein source, poultry dropping has a higher yield and nutrient profile.

Canna x generalis plant is proved as a wetland species identified for the treatment of partially treated domestic wastewater. Mycrophyte chaff harvested from wetland system is commonly discharged into the environment, posing a hazard to the friendliness of the environment. There are examples of plant chaff being used as a renewable energy source, particularly in the production of bio gas. Therefore a study on the biogas production from blends of canna x generalis plant chaff with cow dung and Poultry waste is carried out. The wastes are blended as Canna chaff and Cow dung (CC: CD), Canna chaff and Poultry dropping (CC: PD), all in different ratios, while the CC alone served as control. The CC waste is ground, blended with cow dung and Poultry waste and charged to the digesters in the prescribed ratio. The moisture content of the wastes are determined as the water to waste ratio. The anaerobic digestion is operated under a mesophilic temperature range of 23°C - 37°C during the digestion period. Findings revealed that the cumulative biogas yield from cow dung and canna chaff in 1:3 and 1:4 ratios is 40 % higher than the cumulative biogas yield from canna chaff alone. The cumulative biogas produced by combining Poultry droppings and canna chaff in a 1:3 ratio is 32 percent more than the cumulative biogas yield with substrate canna chaff alone. All the blends commenced flammable gas production within 24 hr of charging the digesters, however, the gas flammability was not sustained and gas production decreased considerably after 4th day. Overall results show that blending the canna plant chaff with cow dung and Poultry droppings in proportion 1:3 yielded maximum cumulative biogas over the entire digestion period.

The present study identified the most effective fertilizer based on the nutritional quality of Chironomidae (Chironomus sp, benthic macroinvertebrates) produced from organic fertilizer. The objective was to ascertain the most effective fertilizer based on the nutritional value of benthic organisms produced from cow dung, rabbit droppings, poultry droppings and pig manure. The experimental design consisted of 24 Chironomidae production ponds. Twenty-four rectangular ponds (1m x 1m) of approximately 1 m3 volume mounted in series, exposed to the open air. Each pond was filled 25 dm3 of substrate, fourty (40) liters of borehole water and immediately fertilized. The dose of 140 g/dm3 of different fertilizers was used for the production of freshwater genuine Chironomidae. The density of Chironomidae in the various production media was significant and found to be 2797 individuals/dm3, 2657 ind/dm3 for cow dung, 2573 ind/dm3 and 2432 ind/dm3 for rabbit droppings, cow dung, pig manure and poultry droppings, respectively. The evaluation of protein content of Chironomidae produced from cow dung, rabbit droppings, poultry droppings and pig manure resulted in 17.57%, 22.98%, 26.80% and 20.48%, respectively. The survival rates of Clarias gariepinus fry fed on Chironomidae produced from cow dung, rabbit droppings, poultry droppings and pig manure and treatment control (Coppens) were found to be optimal (94 ± 0.22), (92 ± 2.38), (95 ± 0.73), (95 ± 0.76) and (95 ± 1.32) and significant, respectively, when compared to those fed on Coppens. Chironomidae with rate protein significant contents between 22 and 26% of rabbit droppings and poultry droppings, respectively, with levels of liposoluble and water-soluble vitamins can substitute imported feed at the first stage of fry.

The study was conducted during rainy season between May and August 2019 at the Teaching and Research Farm of Crop Science and Horticulture, Faculty of Agriculture, Chukwuemeka Odumegwu Ojukwu University, Igbariam Campus. This experiment was carried out to test the effect of different organic manure viz; cow manure, poultry droppings and pig manure and inorganic fertilizer N.P.K 15:15:15 on the growth and yield of fluted pumpkin. There were five treatments: Control, 10t/ha Poultry droppings, 12t/ha Cow manure, 10t/ha Pig manure and N.P.K 15:15:15 which was replicated four times making it 20 plots. The experiment was laid in a Randomized Complete Block Design. Data were collected on Seedling Emergence Percentage, Number of Leaves, Number of Branches, Vine Length and Fresh Weight of Leaf. At 2WAP and 6WAP for Number of leaves cow manure gave the highest mean number while at 4WAP, pig manure came out highest. For Number of branches at 2WAP and 6WAP, Pig manure gave the highest mean value while at 4WAP, Cow manure performed best. For VIne Length, Pig manure gave the highest mean number at both 2WAP and 4WAP. While at 4WAP Poultry droppings performed highest. For Fresh Weight of Fluted pumpkin Cow manure performed the highest at both 8WAP and 11WAP.However, these parameters showed an increase with the application of the different organic manure (Poultry droppings, Cow manure and Pig manure) while N.P.K 15:15:15 and control (untreated plot) did not successfully show much increased on the growth and yield parameters measured. Based on the result of the study, the parameters suggests that Organic manure releases enough nutrient elements which are required for maximum growth and yield of fluted pumpkin and they are recommended as soil amendment for soil productivity and high crop yield

A field experiment was conducted at Teaching and Research Farm, Adamawa State University, Mubi, in the Northern Guinea Savanna of Nigeria during the 2017 growing season June to December 2017, to investigate the response of tiger nuts (Cyperus esculentus L.) to NPK, Cattle dung and Poultry droppings with the objective of selecting the best fertilizer combinations that can boost the yield of tiger nut. The treatments consisted of T1=240kgha-1 NPK, T2= 240kgha-1 Poultry droppings (PD), T3= 480kg-1 Cow dung (CD) T4=177.5kgha-1 NPK+62.5kgha-1 Poultry droppings (PD), T5=177.5kg-1 NPK +302.5kg-1 Cow dung (CD) T6=100kgha-1 NPK+ 140kgha-1 Poultry droppings (PD)+240kg-1 Cow dung (CD) T7= Control (no fertilizer treatment). The experiment was laid out in a Randomized Complete Block Design (RCBD), in three (3) replicates data was collected on Plant height, Number of leaves, Days of 50% flowering, Days to 90% maturity, Number of tuber per plant, 100 tuber weight, tuber yield per plot and tuber yield kg/ha. Data collected was subjected to Analysis of Variance (ANOVA) using MINITAB computer software program, significant means were separated using Duncan Multiple Range Test (DMRT) at P ≤ 0.05. Simple Pearson correlation was also conducted to show the relationship between these observed characters to yield. The result revealed that, the soil treated with the mixture of 100kgha-1 NPK+ 140kgha-1 Poultry droppings (PD)+240kg-1 Cow dung (CD) recorded the fastest growth, yielded the highest number of leaves, produced the heaviest tuber weight, highest number of tuber per plan, tuber yield per plot and tuber yield in Kgha-1 compared with the other treatments. The findings from this research revealed that a mixture of 100kgha-1 NPK+ 140kgha-1 Poultry droppings (PD) + 240kgha-1 Cow dung is the best fertilizer combination and rate that can enhance the yield of tiger nut. Significant positive correlation between tuber yield and plant height number of leaves, hundred tuber weights, number of tuber per plant, and tuber yield per plant suggest that increase in these characters will lead to increase in tuber yield of tiger nut, hence these are important characters to be considered when planning for hybridization involving tiger nut for yield improvement.

IN GENERALIn this thesis the possibilities for digestion of cow and pig manure are described for a completely stirred tank reactor system (CSTR) and an accumulation system (AC-system).For this purpose were researched:1. Anaerobic digestion of cow manure. Optimization of the digestion process for energy production on dairy farms.2. Digestion of manure at lower temperatures.The goal of the first mentioned research was optimization of anaerobic digestion of cow manure in a mesophilic CSTR-system. The results of this research as well as practice experience show that without considerable problems a stable anaerobic digestion process is obtained. Further application of anaerobic digestion of animal slurries on farm-scale in CSTR-systems under mesophilic conditions is at the present energy prices economically not remunerative. This was an important reason for starting research on the applicability of simpler and cheaper systems for digesting manure, such as an accumulation system (AC- system) at lower temperatures.A major part of research on manure digestion is carried out in mesophilic conditions and also in practice the application is mostly in the mesophilic temperature range (Demuynck et al., 1984). Results of laboratory research (v. Velsen, 1981; Hawkes et al. , 1984; Yaldiz, 1987; Hill et al. , 1983) offered little perspective for application of low temperature digestion in practice. Results in this thesis show that the retention times in the above mentioned research were to short to reach a stable digestion at lower temperatures.The goal of the research on digestion of manure at lower temperatures was to obtain insight into processes concerning anaerobic digestion of manure at low temperatures and to investigate the applicability of digestion and storage in a so-called AC-system.A CSTR-system is characterized by a constant supply of fresh manure as well as by a constant removal of digested manure. The sludge load is therefore constant. An AC-system is also characterized by a constant supply of fresh manure, but the removal of digested manure only takes place once per filling (storage) period. The small inoculation at the start of the filling period, typical for an AC-system, results in a high initial sludge load. Through the growth of the biomass during the filling time the sludge load will decrease.START-UP OF SLURRY DIGESTION SYSTEMS.It is clear that the first start-up should be carried out with inoculation material as much as possible adapted to the digestion conditions. However such inoculation material is hardly ever available. It is therefore important to know the factors affecting start-up and the stability of the ultimate digestion process, such as:- process temperature.- the quality of the inoculation material.- the amount available inoculation material.- sludge load.Chapter 2 and 3 of this thesis describe the start-up of manure digestion in several systems. The results presented in Chapter 2 show that with batch wise digestion of fresh manure without inoculation at 5, 10 and 15°C no methane is produced within a 5 months period. Methane production at these low temperatures is possible when high inoculation percentages are applied. A 50% inoculation shows even at a process temperature as low as 5°C methane production.Systems, also without inoculation, at process temperatures of 20°C and higher will obtain in a relatively short time sufficient methanogenic activity. With batch wise digestion of fresh cow manure at 25 and 30°C the lag-phase is respectively ± 60 and 20 days, while the accumulated fatty acids are converted into methane in 125 en 75 days. With a non-inoculated manure digestion start-up the quality of the manure to be digested is of considerable importance. When manure has been stored for some time a sort of pre-start- up has taken place. This explains the relative short lag-phase (respectively ± 20 and 60 days) at the start- up of an AC-system for digesting stored cow and pig manure at 20°C.The results in Chapter 2 also show that a non-inoculated start-up at temperatures of 15°C and lower, will cover an extended period of time. High inoculation provides a fast start-up, even at low temperatures, but is mostly not feasible in practice.Chapter 3 describes the realization of start-up of an AC-system at 15°C with low inoculation (1-13%). The quality of the inoculation material appears to be of great importance for the proceeding of the start- up. This quality is highly dependable on the cultivation conditions, viz.:- The type of digestion system used.- The applied process temperature.The used digestion systemResearch results show that digested manure from a CSTR-system is not suitable for starting-up an AC-system at 15°C 1-13% inoculation and 100 days filling time. In order to remove accumulated fatty acids when starting-up an AC-system on cow manure, extreme long digestion times are required (240-310 days), under the above mentioned conditions and inoculated with at 20°C digested CSTR-system manure (20°C -CSTR-sludge). At a following 'second start-up', 13% inoculated with the 'freshly' digested material, the start-up period is only 150 instead of 240 days. The 'first start-up' is characterized by a successive degradation of acetic and propionic acid, whereas in the 'second start-up' with AC-sludge these fatty acids are removed simultaneously. Similar results can be achieved with the start-up of an AC-system at 15°C for the digestion of pig manure with 15°C-CSTR-sludge as inoculation.The applied process temperatureThe quality of the inoculation material is not only influenced by the system in which it was cultivated but also by the temperature it was liable to. The starting-up of an AC-system at 15°C will proceed faster with a 15% inoculation of 15°C-AC-sludge than with 20°C-AC-sludge. Similar results have been found with batch digestion of manure. Inoculation with sludge cultivated at 18°C will give a higher gas production in batch digestion at 20°C than inoculum cultivated at 27 and 35°C. At process temperatures of 27 and 35°C. the mentioned inocula show little difference in gas production. Wellinger and Kaufmann (1982) and Cullimore et al. (1985) also found this acclimatization of the sludge to lower temperatures.When using the same amount and type of inoculum at a digestion temperature of 20°C the starting-up period in an AC-system is considerable shorter than at 15°C. At 20°C the accumulated fatty acids can be converted within the filling time of 100 days with a 7-13% inoculum, whereas at 15°C a start-up period of at least 240 days was required.In practice non or little adapted inoculum is available. It is than recommendable to operate the AC- system during the first start-up at 20°C. The following filling can be conducted at 15°C In practice this means AC-systems should be started-up preferably in summer or additional heating should be installed. When it is impossible to raise the process temperature temporarily, additional storage capacity should be available, in order to convert the accumulated fatty acids and to obtain a sludge with sufficient C2 and C3 degradation capacity.NH4+-N is a major inhibition component in the digestion of manure. When sludge unadapted for high NH4+-N concentrations, is used for starting-up an AC-system, an adaptation period should be taken into calculation, in which the fatty acid degradation and gas production will stagnate (v. Velsen, 1981). With the start-up of AC-systems on pig manure, Hill et al. (1983) attribute the inhibition of the methane production to the high concentrations of accumulated fatty acids, when sewage sludge was used as inoculum. The results in Chapter 3 indicate that when unadapted inoculum (such as sewage sludge and granular sludge) is used in an AC-system for digesting manure with a relatively high NH4+-N concentration, an adaptation period is required to NH4+-N in which a stagnation of the fatty acid degradation and gas production will occur. The results of starting-up experiments of both CSTR- as AC-systems with CSTR sludge (presented respectively in Chapter 2 and 3) indicate that also inhibition by fatty acids can appear, viz.:- When a CSTR-system at 20°C is started-up with mesophilic sludge operated at a high sludge loading, the 'steady state' is characterized by a high fatty acid concentration in the effluent and low gas production. However when the sludge loading is increased step wise, other conditions unchanged, the 'steady state' is characterized by a low fatty acid concentration in the effluent and a high gas production.- When 50% (20°C -CSTR-sludge is used as inoculum for starting-up an AC-system for treating cow manure at 15°C the lowest gas production was observed with the highest sludge loading (ft= 70 days instead of 100 days). The results of the experiments with as well the CSTR- as the AC-system show that the inhibition can be terminated by a temporary raise of the process temperature.PROCESS MANAGEMENT OF CSTR- AND AC-SYSTEMS.Results concerning continuous experiments with CSTR- and AC-systems are described in Chapter 4 and 5. The methane production in the digestion of manure depends on the course of hydrolysis, acidification and methanogenesis. Temperature and applied loading are the two most important process parameters .The research concerning the digestion in completely mixed systems is carried out with cow manure in a temperature range from 15 to 40°C. It is indeed possible to obtain a stable digestion at 15°C but in this case very long retention times are required (~! 100 days). Also the gas production is then considerably lower compared with a digestion at 30°C and 20 days retention time. This lower gas production is caused by a reduced hydrolysis.Digestion at 20°C and a retention time of 100 days results in a similar gas production as a digestion at 30°C and 20 days retention time. Under these conditions approximately 25% of the influent COD is converted to methane gas. About half of this origins from fatty acids already present in the influent and the rest is derived through hydrolysis of suspended solids. At longer retention times no significant increase of the specific gas production is found. With an increase to 35°C only at a retention time of 15 days a small significant increase of the gas production is observed. With process temperatures of 30-35°C the specific gas production (m3/m3 manure) increases with increasing retention times ranging from 10-20 days. The hydrolysis is the rate limiting step. The non-VFA-dissolved-COD fraction is inert to anaerobic treatment. For non of the investigated process conditions a reduction of this non-fatty acid dissolved COD is found.Digestion at 30-35°C in a CSTR-system is well capable of dealing with sudden increases of the loading as a result of decreases of retention time. A one step reduction of the retention time of 15, 20, 25 or 30 to 10 leads to a direct increase of the gas production and only a minor raise of the effluent fatty acid concentration. In this way the volumetric gas production (m3/m3.day) can be more than doubled within a few days. In practice the methane production can be adapted, in this way, to the energy demand at that moment.In Chapter 5 results of cow and pig manure digestion in AC-systems are presented. The course of the digestion is dependent on process temperature, filling time, percentage inoculation and the composition and concentration of the manure.The results of experiments with cow manure give an insight in the stability of the process during several successive filling periods at process temperatures of 15 and 20°C When digesting cow manure (influent COD= 95-113 g/l) at 15°C in an AC-system with a 15% inoculation, a 'steady state' can not be reached within the filling time of 100 days. An extra digestion period of 40-50 days is necessary for a complete conversion of the accumulated fatty acids. The course of the following filling periods is more or less identical. A change of manure composition (95 ->113 g/l COD, 1.9 ->3.5 g/l NH4+-N) results in an increase of the digestion time in order to degrade the accumulated fatty acids. The gas production rate however, remains almost the same.The AC-digestion of cow manure (95 g COD/l) at 20°C has been conducted with inoculation percentages of 1, 7 and 13% at a filling period of 100 days. Even with the lowest inoculation the accumulated fatty acids are nearly completely converted during the filling time of 100 days. When an inoculation of 7 and 13% is applied, a considerable part of the filling period is in a 'steady state'.Considering the better perspectives for practical application of AC-systems for pig manure instead of cow manure, more extended research was conducted with pig manure.When applying digested cow manure (15°C-AC-sludge) as inoculation for digesting pig manure (74 g COD/l; 3.7 g NH4+-N/l) at 15°C higher gas production rates are found than for digesting cow manure (113 g COD/l; 3.5 NH4+-N/l) under the same process conditions. However also with the digestion of pig manure it is not possible to covert the accumulated fatty acids within the filling period, a post digestion of ± 50 days is required. Theoretically a minimal inoculation of 25% is necessary in order to convert the accumulated fatty acids within the filling period. With filling periods of 270 days a 10% inoculation will be sufficient. At a manure production of 1 m3/day reactor volumes of respectively 133 and 300 m 3should be installed.When digesting more concentrated pig manure (118 g COD/l; 5.9 g NH4+-N/l) in an AC-system at 15°C this results in an accumulation of propionic acid. Even after extreme long digesting periods (100+180 days post digestion) no degradation of propionic acid is shown. Probably the high concentration of NH4+-N (5.9 g/l) in the manure is the cause of stagnation of the propionic acid breakdown.An increase of process temperature from 15 to 30°C with a similar filling time, results in an increase of as well the volumetric as the specific gas production. Both the hydrolysis and the methane generation increase with a raise of temperature from 15 to 30°C.In contrast with a process temperature of 15°C higher temperatures (20 and 30°C) induce hardly any difference in gas production and fatty acid course when the manure concentration is lowered from 118 to 74 g COD/l; The accumulated fatty acids are degraded into methane respectively in 140 and 120 days, at (20°C at 30°C) this is respectively 50 and 40 days, after which a steady state occurs. The specific growth rate of the methanogens as well for 20 as for 30°C does not differ with concentrated or diluted manure.Results of the executed research show, that intensive stirring in the AC-systems with a high initial loading (e.g. a 15% inoculation and a 100 day filling period at a process temperature of 15°C) has a strong negative effect on the degradation of propionic acid and to a lesser extent on acetic acid. In an AC- system with a high initial activity (e.g. a 10% inoculation and a 100 days filling time at process temperatures of 20 and 30°C hardly or no negative effect of stirring was found. It should be concluded that intensive mixing is process technologically unfavorably. Only for reasons of management some stirring can be useful, e.g. when removing the digested manure or when heating is applied.TOXICITYIn Chapter 6 the results are discussed of the research dealing with the effect of organic matter and the NH4+-N concentration on the digestion of cow manure in CSTR-systems, at a process temperature of 30°C and a retention time of 10 days. The organic matter concentration of the manure, within a range of 2-7%, has no effect on the digestion. The NH4+-Nconcentration however has a very distinct effect, as well on the hydrolysis as on the methanogenesis. The effluent fatty acid concentration increases exponentially and the hydrolysis declines linear with NH4+-N concentrations in the range of 1.2-4.9 g/l The relation between the percentage hydrolysis in the reactor (H R ) and the NH4+-N concentration can be empirically described with the equation:H R = 22.8-4.16 [NH4+-N].When digesting manure with a high NH4+-N concentration (4.9 g/l) at relative short retention times, two different equilibrium effluent fatty acid concentrations can establish. The lowest concentration can be achieved through a temporarily lowering of the loading. Similar results were found with starting up digesters at lower temperatures as described in Chapter 2 and probably can be attributed to the inhibitory effect of fatty acids.Results of research on CSTR-systems show a clear negative effect of NH4+-N, this is however not the case with AC-systems at 20 and 30°CAPPLICABILITY OF AC- AND CSTR-SYSTEMS.The digestion of manure in CSTR-systems for gas production on farm-scale is applied in the Netherlands since 1979. Between 1979-1982 ± 25 installations have come into operation on pig and dairy farms. The development of the energy prices is the main factor causing no further growth of biogas installations after 1982.The earning-capacity of biogas installations was apart from the drop of energy prices, negatively influenced by the considerable lower efficiencies of the installations (especially on piggeries) found in comparison with laboratory and semi-technical investigations. The cause of this is the occurrence of 'pre- digestion' in the manure storage. In fact, every farmer has got already a digester, however the process is not optimized and the gas is not collected and used. This finding gave the main rise to investigate the possibilities of combined storage and digestion. The application of an AC-system, in which the storage and digestion is combined, is in principle also much more suitable for manure digestion on farm-scale than the CSTR-system, for no extra reactor and/or effluent storage is required. Present developments on manure handling, viz., the required extension of manure storage and the requirement to cover the storage gas-tight for eliminating emission of NH3, make that the storage starts to resemble a digester.The results presented in this thesis show clearly that an increase of the storage time can result in an important raise of the gas production, even at low temperatures 15°C Since it is known that CH 4 contributes by far more severe to the greenhouse effect than CO 2 (Goossensen & Meeuwissen, 1990), the biogas production during storage should be avoided or optimized and used in order to save fossil fuel. In the latter way a contribution can be made to fight the greenhouse effect.The obtained results also show that avoiding methane production is very difficult. When a suitable bacterial population has established the methanogenesis will develop irrevocably, unless inhibitory substances are used. The latter is from an environmental point of view not recommendable. At a manure temperature of 20°C as it can occur in summer, 1% inoculation is enough to start the digestion process within the filling period. Since practice shows it is impossible to empty manure storages completely, approximately 10-15% of the manure in general remains, it can be concluded from the obtained results that with the extension of storage time to 5 months or longer also at temperatures of 15°C, considerable gas production will appear. At the test accommodation for piggery at Rosmalen a 700 m3 manure silo was isolated, covered gas-tight and equipped with a simple heating system. During two years research was done on the combination of storage and digestion of manure at ± 18°C. When it becomes compulsory to cover manure storages gas-tight, the combination of manure storage and digestion will certainly becomes an attractive alternative.The use of an AC-system is in principle suitable when long term storage is compulsory. In the present situation in the Netherlands, where much organic manure is produced, a major part of this manure will have to be processed. When processing manure a maximal regain and re-use of valuable products and a minimal use of energy should be aimed. Anaerobic digestion as a part of such a system is to be seen as a method to remove and convert a major part of the solid and soluble organic fraction of the manure into methane. The methane produced can be used as energy for further process steps. When there is no need for longer storage if manure is processed on a large scale, the AC-system is less attractive than the CSTR-system.By anaerobic digestion only a part of the organic compounds can be converted into methane. A further removal of solids can be accomplished by mechanical separation after or if possible before digestion. Mechanical separation of the 'fresh' slurry, into a solid and soluble fraction, has the advantage of a possible separate digestion of the fractions, the soluble fraction in a high loaded reactor, e.g. an UASB and the solid fraction in a low loaded reactor. In this way the total required reactor volume can be considerably reduced.The soluble fraction contains the major part of the nitrogen, while the solid fraction contains most of the phosphor. The nitrogen in the soluble fraction is mainly present as NH4+-N. An in principle very attractive system for removal of NH4+-N (and phosphate) in the soluble fraction is the stripping/absorption process. A diagram of this process is given in Figure 1 (v. Velsen, 1985).It is incomprehensible that this system or other modified systems of this (Drese, 1988) are not yet tested on large scale.From the point of view of appropriate use of resources it is necessary to regain and recycle the large amounts of nitrogen from the manure and not as proposed sometimes (Koster, 1990) to convert this into nitrogen gas by means of nitrification/denitrification, especially because this requires vast amounts of high grade energy. Complete recovery of NH4+-N is not always necessary or economically justified. A combination of the stripping/absorption with the nitrification/denitrification process should at least be considered.

Vegetable cultivation contributes significantly to food production, providing a varied and nutritious food supply for human use and Climate-smart agriculture (CSA) practice is recommended in recent times for agricultural practice. Fluted pumpkin is an essential food crop farmed by small-scale farmers, and it helps fight against malnutrition in Nigeria. This study assessed the growth performance of Fluted Pumpkin cultivation in mbaise, Imo State, for the period of 3 months, using organic manure, which includes cow dung, pig dung, and poultry droppings, as sources of soil nutrients. Randomized Block Design was used for the experimental design and there were three treatments and a control (untreated pot), 1kg per pot of composted cow dung, pig dung, and poultry droppings, which were replicated three times, making it 12 pots. Parameters measured were on the number and length of leaves at 2 weeks, 4 weeks, and 8 weeks and presented in tables. The results show that these parameters have a growth increase by applying different organic manure (cow dung, pig dung, poultry dropping) to the pumpkin pot, in contrast to the control (Untreated pot). However, the treatment with poultry droppings and cow dung had the highest leaf counts compared with the control pot, and pig dung had the lowest performance rate among the three organic manure types used. The result of the growth parameter revealed a significant (P<0.05) difference in all the treatments used. The study recommends the use of organic manure for fluted pumpkin cultivation, especially poultry droppings. It suggests using different organic manure for maximum growth and yield, which are essential for soil amendment and productivity. Therefore, farmers are advised to adopt climate-smart agricultural techniques to help boost their food crop production, ensure food security, promote policy formation, and improve sustainable farming methods.

Poultry manure and cow dung have been established as potential material for the bioremediation of petroleum polluted sites, with emphasis on nutrient addition. Our aim was to isolate from poultry droppings and cow dung bacteria with ability to degrade petroleum hydrocarbons. Bacteria were isolated from poultry droppings and cow dung by continuous enrichment and vapor transfer techniques. Petroleum utilization by each isolate was confirmed in carbon free medium containing Escravos crude oil (1%). The two best isolates were selected for further study. Isolates were identified by Analytical Profile Index (API). Antibiotic sensitivity was determined by multidisc. Growth was assayed in broth culture by plate count. Residual oil was determined by Gas Chromatography equipped with Flame Ionisation detector (GC-FID). The isolates were putatively identified as Pseudomonas putida (MP2) and Pseudomonas sp. (MC4). Both isolates were susceptible to ciprofloxacin and chloramphenicol and tarivid. They resisted amoxicillin and gentamycin, augmentin, sparfloxacin and septrin. The growth rates were 0.17 and 0.23/day for strains MP2 and MC4 respectively, while the organisms degraded 88.39% and 89.06 % of crude oil respectively in 20 days. Aliphathic hydrocarbons in the range C11 to C22 were mostly reduced to less than 20%, while C22 – C26 disappeared completely within the same period in both cases. Bacteria capable of extensive degradation of Escravos crude oil were isolated from poultry droppings and cow dung. Such isolates could be veritable candidates for bioaugmentation of hydrocarbon polluted environmental compartments.

The advantages of recording micro change in pressure every second inside a biogas production digester using strain gage measurement was well demonstrated in this work. The production of biogas from a composite of Lemon grass and Poultry droppings was carried out by measuring the total gas pressure exerted on the surface of sealed near-cylindrical plastic container used as a digester. The suitability of using a combination of lemon grass and poultry droppings for biogas generation and the determination of an optimal mixing ratio to maximize gas production was studied. The aerobically pre-fermented substrates were mixed in five different ratios labelled ‘Digester A-E’ respectively to form composite and the formed slurry was digested for 30 days in the five (5) different digesters lagged with fiberglass wool. Pressure values were determined using the principles of ‘thin walled cylindrical pressure vessel’ computed from the strain gage rosette readings. The results after 30 days show that Digester B with lemon grass had the highest gas production with a pressure of 41.8 kP. Digester C which contained 100% chicken droppings had a pressure of about 11.5 kP, but when mixed with lemon grass inside digester E, in a mixing ratio of 70% to 30% respectively, the pressure of the gas produced increased to 26.5 kP. This is an increase of about 15 kP which is a little over double the amount of gas produced with only chicken droppings. Thus, the result of mixing 30% of lemon grass and 70% of chicken droppings doubled the gas production potential of chicken droppings. Digester A (with 50% lemon grass and 50% chicken droppings) and Digester D (with 70% lemon grass and 30% chicken droppings) had pressures of 17.4 kP and 32.7 kP respectively.

Rice straw co-digestion potential with cow dung and poultry droppings for maximizing biogas production in Bangladesh.

Performance evaluation of three different-shaped bio-digesters for biogas production and optimization by artificial neural network integrated with genetic algorithm

Vermistabilization of textile mill sludge spiked with poultry droppings by an epigeic earthworm Eisenia foetida

A field experiment was conducted from August to November 2023 at the Instructional Fish Farm, College of Fisheries, Acharya Narendra Deva University of Agriculture & Technology, Kumarganj Ayodhya, Uttar Pradesh. The study aimed to assess water quality parameters. The experimental design included fifteen earthen ponds (8m × 8m × 1m), divided into five treatments with three replicates each. The treatments were as follows: (T1) control with pond bottom soil base, (T2) pond bottom soil with cattle dung at 20 t/ha, (T3) pond bottom soil with cattle dung at 15 t/ha, (T4) pond bottom soil with poultry droppings at 10 t/ha, and (T5) pond bottom soil with poultry droppings at 7.5 t/ha. Over the 90-day experimental period each pond evaluated the effects of cattle dung andpoultry droppings on water quality parameter. Results demonstrated that the treatment with poultry droppings at 10 t/ha (T4) significantly enhanced water quality, proving to be superior to treatments with cattle dung, followed by treatment T2 (20 t/ha cattle dung).