Effects of stocking rate and moisture content on the growth and maturation of Eisenia andrei (Oligochaeta) in pig manure

The research conducted earlier in our country was mainly aimed at solving the problem of rational use of liquid manure produced in large pig breeding enterprises. How-ever, more than 70% of pork is produced on small, medi-um-size and large farms represented by several technolog-ical premises. In these enterprises, the issues of pro-cessing liquid manure as the experience of their operation in the Southern Federal District shows are resolved unsat-isfactorily. One of the advanced solutions is the use of a mobile unit for the separation of liquid pig manure into frac-tions, the basic element of which is a brush auger. The separation process in the auger occurs in the filtration zones with the production of sediment and squeezing with the production of a solid fraction. The results of experi-mental studies to determine the moisture content of the sediment in various parts of the filtration zone arepresent-ed. It has been found that this indicator depends on the length of the filtration and dewatering zones, the angle of inclination of the screw to the horizon and the rotation fre-quency of the screw. The obtained results allowed deter-mining the length of the filtration and dewatering zones, the sum of which should not exceed 4 m, the angle of inclina-tion of the auger -up to 30° and the rotation frequency within 6.3-9.4 s-1. At the same time, the moisture content of the sediment at the exit from the dewatering zone is from 83.5% up to 78.8%

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Influence of moisture content of solid-state NaOH pretreatment and codigestion on methane production in the semi-dry anaerobic digestion of rose stalk

BioResources ◽

10.15376/biores.14.2.4210-4223 ◽

2019 ◽

Vol 14 (2) ◽

pp. 4210-4223

Author(s):

Yongsheng Chen ◽

Zhijuan Ke ◽

Yue-gan Liang

Keyword(s):

Anaerobic Digestion ◽

Solid State ◽

Moisture Content ◽

Methane Production ◽

Biogas Production ◽

Pig Manure ◽

Naoh Pretreatment ◽

Production Kinetics ◽

Anaerobic Codigestion ◽

Dry Anaerobic Digestion

Large quantities of burned or abandoned rose stalks are leading to serious environmental pollution. In this study, the effect of the moisture content of a solid-state NaOH pretreatment on methane production was first determined by a biochemical methane potential test. Then, the effect of codigestion with pig manure on methane production was investigated under the optimal moisture via thermophilic semi-dry anaerobic digestion by leaching bed reactor. Biogas production kinetic was assessed by the first-order kinetic model and modified Gompertz model. An increase in methane yield and biogas production kinetics was shown in the solid-state NaOH pretreated biomass. There was no significant difference in methane production for the three moisture contents studied during pretreatment (54%, 70%, and 77%). The anaerobic codigestion of rose stalk and pig manure increased 41% to 52% for methane yields and improved biogas production kinetics compared with monodigestion of rose stalk. Anaerobic codigestion did not greatly change the process stability, except for NH4+-N. The optimal process for the anaerobic digestion of rose stalk was as follows. The rose stalk was initially pretreated via solid-state NaOH pretreatment with a moisture content of 70%. Then, the pretreated rose stalk was co-digested with pig manure at a total solids ratio of 1:1.

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Substantiation of optimum relative humidity of slurry when applying the batch-type gravity flow system for its removal

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/845/1/012141 ◽

2021 ◽

Vol 845 (1) ◽

pp. 012141

Author(s):

A V Trifanov ◽

V I Bazykin ◽

I E Plaksin ◽

E A Tikhonov ◽

I V Grigorev

Keyword(s):

Relative Humidity ◽

Moisture Content ◽

Flow System ◽

Negative Impact ◽

Residual Layer ◽

Gravity Flow ◽

Pig Manure ◽

Burial Depth ◽

Batch Type ◽

Pig Farms

Abstract The batch-type gravity flow system for slurry removal is most commonly installed on the new and reconstructed pig farms. The newly designed system is characterized by the presence of plastic sewing pipes under each slurry-collecting canal. Such a system allows for complete automation of slurry removal and, under proper operation, mitigates the negative impact of pig farms on the environment through the lower annual output of slurry. The paper presents the calculation of the main design parameter of the system, such as the depth of slurry pits and the burial depth of longitudinal and transverse slurry collectors. Under the increase of pig manure humidity from 88% to 90%, the height of the residual layer decreases owing to lower manure shear stress in the part, where the manure moisture content increases. Under the relative humidity above 91%, the height of the residual layer in the pit increases rapidly due to the intensive stratification of slurry into fractions. Thus, the minimum height of the residual layer in the pit is achieved at the relative moisture content of 89-91%. Slurry should be accumulated in the pits to the 3/4 or 4/5 of the height (depth) of the pit. The accumulation period must be a multiple of the operating cycles of housing of various age and gender groups of pigs.

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