PHYSICAL AND ENGINEERING PROPERTIES OF PEAT SOIL STABILIZED WITH THE ADMIXTURE OF CACO3+RICE HUSK ASH DUE TO WATER INFILTRATION FROM SURROUNDING AREAS

Peat is a type of soil with high organic content, very low bearing capacity, and high uneven settlement. Some methods to improve soil have been applied to peat in order to make it strong enough for civilization-building foundation situated on it. Peat stabilization is a method that is continuously developed considering that the cost it needs is lower and this approach is more environmentally friendly compared to other methods. The admixture of lime (CaCO3) and Rice husk ash, a new ecofriendly stabilizer material, has been applied to peat soil and showed a good result. However, in studies conducted previously, the effect of water infiltration from surrounding areas of soil was stabilized was not involved as variable influencing the change of parameter. Based on that, this laboratory study was carried out to model the real condition in the field when the stabilization is performed and to identify the physical and engineering changes of peat soil in the 10th, 20th, and 30th days of stabilization in its border and middle parts, with the percentage of material stabilizer 5%, 10%, 15% and 20% of the unit weight of the initial condition of peat. The result of laboratory test shows that the addition of admixture of lime (CaCO3) and rice husk ash can improve the physical and engineering properties of peat soil are stabilized. Water infiltration occurred on peat soil is stabilized has not affected the physical and engineering properties of the soil. It can be seen from the physical and engineering properties of the border and central parts of peat soil is stabilized that still have a similar value. It is assumed to be caused by CaSiO3 gel formed still needs a longer duration to become stable gel. However, in this initial study it was known that the more stabilizers added, made the better the parameters of the stabilized peat soil.

Potential of peat carbon storage in natural forests Tripa Peat Swamp at Aceh Barat Daya District

Carbon storage is the total weight of carbon stored in the ecosystem at a certain time, especially in natural forests in the Tripa peat swamp area of Aceh Barat Daya. Peatlands are wetland ecosystems that are formed by the accumulation of organic matter on the forest floor from weathering of the vegetation on it over a long period of time. The research objectives were 1) to calculate peat soil carbon storage and 2) to measure the depth of peat soil in natural forest in the Tripa peat swamp area, Aceh Barat Daya Regency. The research activity was carried out from February to March 2021, in a natural forest in the Tripa Aceh Barat peat swamp area, divided into three stations and at each station, three sampling plots were made. Data collection using purposive sampling technique, Analysis of carbon stock was analyzed using the formula for calculating carbon stock by entering data on the percentage of soil organic carbon in the laboratory, and data on peat depth in a descriptive analysis. The results showed that the amount of peat soil carbon storage, especially in natural forest in the Tripa Aceh Barat Daya peat swamp area, was 2.556 tons/ha and the peat depth range was fibric with a depth of 0-95 cm, hemic 96-292 cm, and substance 293-310.

EFFECT OF DOLOMITE AND CHICKEN MANURE APPLICATION ON PAK CHOI (Brassica rapa chinensis) PRODUCTION AND CARBON DIOXIDE EMISSIONS IN TROPICAL PEATLANDS

The current study was aimed to determine the effect of ameliorant on Pak choi (Brassica rapa chinensis) productivity, CO2 emissions, and factors affecting the rate of CO2 emission. The study was carried out using a non-factorial completely randomized design with seven treatments. The imposed treatment are without ameliorant (control), 10, 20, 30 ton ha-1 chicken manure, 4 ton ha-1 Dolomite + Chicken Manure @ 10 ton ha-1, Dolomite 4 ton ha-1 + Chicken Manure @ 20 ton ha-1 and Dolomite 4 ton ha-1 + Chicken Manure @ 30 ton ha-1. The variables observed are the chemical properties of peat soil, fresh and dry weight of pak choi, CO2 emissions, and factors that affect CO2 emissions. The results of the study revealed that the combination of Dolomite and chicken manure has a significant effect on the studied parameters and the combination of 4 ton ha-1 dolomite + 30 ton ha-1 chicken manure had the highest pH change (average of 6.36), highest productivity, and CO2 emission (344.42 mg cm-2hr-1). Results of the study can be concluded that Dolomite and chicken manure has a significant effect on the various growth parameters of B. rapa chinensis and the properties of the peat soil.

COMPRESSIVE CAPACITY OF HELICAL PILE FOUNDATION ON PEAT WITH VARIATION OF HELICAL PLATE DIAMETER

<p>The use of helical foundations to support structures on peat soil is still a new method. Research is needed to develop this foundation. There are 6 types of helical foundation tested on peat soil. To study the effect of helical plate diameter, plate diameters were varied with sizes 25 cm (M), 35 cm (L), and 45 cm (G). Plate positions (1, 2, 3 plates) are designed at 300 mm spacing. The axial compression bearing capacity test is carried out based on the constant rate of penetration procedure. At the beginning of loading, the load increases significantly. At a certain descent, the load begins to decrease slowly. The load-settlement curve shows that the larger the plate diameter, the greater the load it can withstand. The largest bearing capacity is produced by the GGG 30 foundation (3 plates dia.45 cm), which is 10.83 kN. LLL 30 helical foundation (3 plates dia.30 cm) provides a bearing capacity of 7.14 kN. These results clearly explain that the increase in plate diameter is directly proportional to the increase in the axial compression bearing capacity.</p>

Microbial growth and attachment of Salmonella and enterohemorrhagic and enteroaggregative Escherichia coli strains on cress microgreens grown in peat soil system

PurposeThis study aimed to investigate how enteric pathogens and their biofilm populations on fresh produce survive according to time that contamination has occurred on leaves and contamination route: seed irrigation water.Design/methodology/approachCress was contaminated in two different ways: contamination of seeds and irrigation water with 8-log MPN/mL bacterial load, Salmonella Newport, Escherichia coli O157:H7, O104:H4 or O78:H2. While contaminated seeds were cultivated for seed contamination, contaminated irrigation was applied at the end of each week to separate groups of samples obtained from cultivated surface-sterile seeds to understand how long these pathogens could survive until harvest.FindingsThe results indicated these pathogens survived until harvest, and formed biofilms on cress leaves grown using both contaminated seeds and irrigation water. No significant difference was observed among populations of Salmonella and E. coli groups in terms of survival (∼4.5–6.0 log MPN/g) and biofilm formation (∼4.4–5.7 log MPN/g) for contamination by seed. Also, SEM images revealed biofilm-like structures, the proofs of the attachment of these pathogens on leaf surfaces.Originality/valueFrom our knowledge this is the first study focusing on the survival and biofilm formation of one Salmonella serotype (Newport) and three E. coli serotypes (O157:H7, O104:H4, and O78:H2), representing enterohemorrhagic and enteroaggregative E. coli pathogenic subgroups, under the same irrigation and growth schemes. Furthermore, this study mimics the contamination of seeds and irrigation water with sewage or wastewater and may shed light on contamination of fresh produce grown using poor wastewater treatment.

Stabilization of Johor Peat Soil using Sugarcane Bagasse Ash (SCBA)

Peat soil have been categorized as a problematic organic soil, because they have a high settlement rate when placed any structure on it. Therefore, the peat soil must first be stabilized using cement before it can be used. However, massive use of cement can lead to environmental pollution. Therefore, this study intends to use sugar cane bagasse ash as a substitute for cement in peat soil stabilization. The mix ratio of 5% to 20% was used to find the optimal mix ratio. Various tests were carried out on samples such as basic properties tests, Unconfined Compressive Strength (UCS) and Scanning Electron Microscope (SEM). After all the tests, the 5% replacement SCBA mix ratio gave the highest unconfined compressive strength if compared to the other mixtures ratio. Therefore, it is selected as the optimum mix ratio. The soil strength achieved by the SCBA 5% replacement ratio was found to be higher than cement stabilization alone due to the presence of secondary pozzolan reactions. The microstructure result from the SEM test had shown that the 5% replacement SCBA mix ratio filled in the hollow left by the peat soil. Hence, able to improve its soil structure and thus increasing its strength.

Thermal Imaging Study on The Effect of Permeability on Smouldering Behaviour of a Tropical Peat

Smouldering is a slow-burning, low-temperature, flameless combustion, and frequently happens in peatland fires. The smouldering spread occurs because of the parameter achievement in oxygen supply, generated heat, and heat released to the environment. The condition of porous and fibrous peat soils makes oxygen supply easily happens. The difficulty of getting to the location of the burning peatland is one of the problems to extinguish the fire. This study aims to observe with thermal imaging study the effect of peat permeability on smouldering behaviour of a tropical peat sample. Mechanical compaction was applied to reduce permeability and pore value in the central of the peat soil. Then, peat soil is ignited to create the smouldering propagation through the compacted peat area. The combustion process that occurs on the surface is observed by a visual camera and an Infrared FLIR Thermal Camera. The initial results showed a reduction in the smouldering spread rate on the compacted soil region as compared to the undisturbed peat smouldering region. Nevertheless, smouldering combustion of peat still occurred in all regions of the reactor, once the smouldering front could penetrate the compacted region.

Full Genome Sequence of a Methanomassiliicoccales Representative Enriched from Peat Soil

The full genome of a Methanomassiliicoccales strain, U3.2.1, was obtained from enrichment cultures of percolation fen peat soil under methanogenic conditions, with methanol and hydrogen as the electron acceptor and donor, respectively. Metagenomic assembly of combined long-read and short-read sequences resulted in a 1.51-Mbp circular genome.

Study of a green algae Lobochlamys segnis Strain-019 from peatland

Characterization of a green algae Lobochlamys segnis strain 019 using morphological dan phylogenetic study were determined. In this study, contribution of natural nutrients will be evaluated by culturing this strain using Sphagnum peat soil extract in comparing to that of a commercial media for freshwater algae. Based on morphological study, L.segnis strain 019 is a unicellular biflagellate. This Chlamydomonas-like algae possessed a cup shaped to lateral chloroplast with central pyrenoid and a low indistinct papilla. Molecular phylogenetic analyses based on 18 S rDNA indicated that this strain is a member of Lobochlamys subclade, and formed a robust clade (PP = 1.0, BP = 99%) with Oogamochlamys. Strain 019 formed a buble-like colonies covered by mucilage material under agar culture condition. In this study, a moderate acidic condition pH 4.0 was applied for both media due to liquid medium of Sphagnum peat soil extract detected in this pH value. The biomass production, lipid production and fatty acid composition using peat soil extract and AF-6 media are evaluated and discussed.