Salustiano Mato

How earthworm density affects microbial biomas and activity in pig manure

We studied the influence of the earthworm, Eisenia fetida, on the microbial populations during the vermicomposting of pig manure. Fresh pig manure was placed in replicated boxes with (two densities, 25 and 50) and without earthworms for a period of 16 d. Samples were destructively collected periodically and analyzed for microbial biomass nitrogen, microbial respiration, substrate-induced respiration (SIR) and substrate dehydrogenase activity. Microbial biomass N, microbial respiration, SIR and substrate dehydrogenase activity were significantly lower in the earthworm treatments after 8 d.

BIOCONVERSION OF SOLID PAPER-PULP MILL SLUDGE BY EARTHWORMS

Bioconversion of solid paper-pulp mill sludges and primary sewage sludge for 40 days at a ratio of 3:1 dw:dw was studied in containers with and without earthworms (Eisenia andrei). This mixture was a suitable medium for optimum growth and reproduction of the earthworms. Regardless of the presence of earthworms, degradation occurred during the bioconversion period, but the presence of earthworms accelerated the mineralization of organic matter, favored the breakdown of structural polysaccharides and increased the humification rate. Consequently, the C/N ratio and the degree of extractability of heavy metals were lower in the worm-worked end product.

Vermicomposting of wastewater sludge from paper-pulp industry with nitrogen rich materials

Abstract The vermicomposting of pulp mill sludge mixed with sewage sludge, pig slurry and poultry slurry at different ratios was studied. Eisenia andrei (Bouche, 1972) showed high growth rates and high mortalities in all the mixtures considered.

The growth and reproduction of Lumbricus rubellus and Dendrobaena rubida in cow manure mixed cultures with Eisenia andrei

Abstract The growth and reproduction of the epigeic species Lumbricus rubellus and Dendrobaena rubida in cow manure and the possible interactions of these species with Eisenia andrei are studied. The mean growth rate of D. rubida was 3.84 mg day−1, reaching sexual maturity at 54 days and producing an average of 1.45 cocoons per week. After collection, 85% of the cocoons of this species were viable, incubation took an average of 21.7 days and an average of 1.67 worms emerged from each cocoon. The mean growth rate of L. rubellus was 8.02 mg day−1, maturing at 74 days and with a mean weekly production of 0.54 cocoons. After an incubation period of 36.5 days, 64% of the cocoons hatched, one worm emerging from each. The mixed cultures tested did not present any advantage over pure cultures. E. andrei showed higher growth rates in mixed cultures, while the growth rate of L. rubellus and D. rubida decreased slightly in mixed cultures as compared to pure cultures.

Changes in microbial dynamics during vermicomposting of fresh and composted sewage sludge

Municipal sewage sludge is a waste with high organic load generated in large quantities that can be treated by biodegradation techniques to reduce its risk to the environment. This research studies vermicomposting and vermicomposting after composting of sewage sludge with the earthworm specie Eisenia andrei. In order to determine the effect that earthworms cause on the microbial dynamics depending on the treatment, the structure and activity of the microbial community was assessed using phospholipid fatty acid analysis and enzyme activities, during 112days of vermicomposting of fresh and composted sewage sludge, with and without earthworms. The presence of earthworms significantly reduced microbial biomass and all microbial groups (Gram+ bacteria, Gram- bacteria and fungi), as well as cellulase and alkaline phosphatase activities. Combined composting-vermicomposting treatment showed a lesser development of earthworms, higher bacterial and fungal biomass than vermicomposting treatment and greater differences, compared with the control without earthworms, in cellulase, β-glucosidase, alkaline and acid phosphatase. Both treatments were suitable for the stabilization of municipal sewage sludge and the combined composting-vermicomposting treatment can be a viable process for maturation of fresh compost.

Evolution of microbial dynamics during the maturation phase of the composting of different types of waste

During composting, facilities usually exert greater control over the bio-oxidative phase of the process, which uses a specific technology and generally has a fixed duration. After this phase, the material is deposited to mature, with less monitoring during the maturation phase. While there has been considerable study of biological parameters during the thermophilic phase, there is less research on the stabilization and maturation phase. This study evaluates the effects of the type of starting material on the evolution of microbial dynamics during the maturation phase of composting. Three waste types were used: sludge from the fish processing industry, municipal sewage sludge and pig manure, each independently mixed with shredded pine wood as bulking agent. The composting system for each waste type comprised a static reactor with capacity of 600L for the bio-oxidative phase followed by stabilization and maturation phase in triplicate 200L boxes for 112days. Phospholipid fatty acids, enzyme activities and physico-chemical parameters were measured throughout the maturation phase. The evolution of the total microbial biomass, Gram + bacteria, Gram - bacteria, fungi and enzymatic activities (β-glucosidase, cellulase, protease, acid and alkaline phosphatase) depended significantly on the waste type (p<0.001). The predominant microbial community for each waste type remained present throughout the maturation process, indicating that the waste type determines the microorganisms that are able to develop at this stage. While fungi predominated during fish sludge maturation, manure and municipal sludge were characterized by a greater proportion of bacteria. Both the structure of the microbial community and enzymatic activities provided important information for monitoring the composting process. More attention should be paid to the maturation phase in order to optimize composting.

Importance of soil exchangeable cations and aluminium content on land snail distribution

Abstract The influence of soil exchangeable cations and aluminium content on the distribution of various terrestrial gastropods was investigated. Calcium was the most important factor, though aluminium and magnesium content also had some effect. Potassium and sodium had no significant influence on distribution. The species most sensitive to the factors analysed were Cochlicopa lubrica, Vertigo pygmaea and Carychium tridentatum.

Activity and partial characterisation of xylanolytic enzymes in the earthworm Eisenia andrei fed on organic wastes

Abstract This study demonstrates the occurrence of active xylanolytic enzymes in extracts from Eisenia andrei , Bouche 1972. Xylanase was the most active enzyme (2.06 U g −1 ), followed by acetyl xylan esterase (0.55 U g −1 ). Lower activities showed β- d -glucuronidase (0.17 U g −1 ), α- l -arabinosidase (0.04 U g −1 ) and β-xylosidase (0.03 U g −1 ). All of the xylanolytic enzymes displayed higher total activity when the earthworms were fed on a xylan-containing medium. Xylanase, α- l -arabinosidase and acetyl xylan esterase showed maximal activity at neutral pH. In contrast, β-xylosidase and β-glucuronidase displayed maximal activity at pH 3.0 and 4.0, respectively. All enzymes displayed a high activity within the physiological temperature range 35 to 40°C. K m and V max values of xylanolytic enzymes were also estimated. Kinetic parameters for xylanase were determined in extracts of earthworms fed on standard medium ( K m =6.91±1.120 mg ml −1 ; V max =0.05±0.002 U mg −1 ), and in extracts of earthworms fed on a medium containing xylan ( K m =5.60±1.070 mg ml −1 ; V max =0.12±0.006 U mg −1 ).

Seafood-Processing Sludge Composting: Changes to Microbial Communities and Physico-Chemical Parameters of Static Treatment versus for Turning during the Maturation Stage

In general, in composting facilities the active, or intensive, stage of the process is done separately from the maturation stage, using a specific technology and time. The pre-composted material to be matured can contain enough biodegradable substrates to cause microbial proliferation, which in turn can cause temperatures to increase. Therefore, not controlling the maturation period during waste management at an industrial level can result in undesired outcomes. The main hypothesis of this study is that controlling the maturation stage through turning provides one with an optimized process when compared to the static approach. The waste used was sludge from a seafood-processing plant, mixed with shredded wood (1:2, v/v). The composting system consists of an intensive stage in a 600L static reactor, followed by maturation in triplicate in 200L boxes for 112 days. Two tests were carried out with the same process in reactor and different treatments in boxes: static maturation and turning during maturation when the temperature went above 55°C. PLFAs, organic matter, pH, electrical conductivity, forms of nitrogen and carbon, hydrolytic enzymes and respiratory activity were periodically measured. Turning significantly increased the duration of the thermophilic phase and consequently increased the organic-matter degradation. PCA differentiated significantly the two treatments in function of tracking parameters, especially pH, total carbon, forms of nitrogen and C/N ratio. So, stability and maturity optimum values for compost were achieved in less time with turnings. Whereas turning resulted in microbial-group stabilization and a low mono/sat ratio, static treatment produced greater variability in microbial groups and a high mono/sat ratio, the presence of more degradable substrates causes changes in microbial communities and their study during maturation gives an approach of the state of organic-matter degradation. Obtaining quality compost and optimizing the composting process requires using turning as a control mechanism during maturation.

Effects of Bulking Agents in Composting of Pig Slurries

The large amounts of slurry wastes produced in intensive farms cause serious disposal and pollution problems. Composting of slurries from animal waste offers an answer to odour nuisance and water pollution associated with their management. The aim of this research was to carry out a preliminar laboratory study trying to transform slurries into compost so they can be used as horticultural substrates, organic soil conditioners or fertilizers.