Compost Water Research Articles

Changes in mineral forms of nitrogen and sulfur and enzymatic activities during composting of lignocellulosic waste and chicken feathers

The aim of this study was to show the dynamics of changes in the activity of enzymes responsible for C, N, and S metabolism, i.e., cellulase, protease, urease, and arylsulfatase in two lignocellulosic composts as well as changes in the concentration of mineral forms important in plant nutrition (N-NH4+, N-NO3−, S-SO42−). Most of the enzyme activity was higher during 10 weeks of composting in compost I, containing higher amounts of easily available organic matter than in compost II. Enzymatic activities in compost II remained at a higher level for a longer time, but they increased at a slower rate. Mineral content changes in the compost mass consisted primarily of an increase in N-NO3− concentration and a decrease in N-NH4+ and S-SO42− levels, especially in compost I. The concentration of mineral nitrogen and sulfur forms in compost water extracts was about 10–100 times lower than in the compost mass. At the end of composting, the amount of sulfates in the compost mass was 30 and 150 mg kg−1 dw in compost II and I, respectively. In this context, the composts obtained should be considered valuable for fertilizing soils poor in this component and for cultivating plants with high sulfate S demand.

The influence of biochar and compost mixtures, water content, and gas flow rate, on the continuous adsorption of methane in a fixed bed column

Biofiltration is an excellent alternative for the treatment of diffuse emissions of methane (CH4) that cannot be treated by physical/chemical means or recovered for energy. Despite the advances on CH4 biological treatment technologies, they are limited by the low aqueous solubility of CH4 into the biofilm where CH4 mineralization occurs. In this study, the CH4 adsorption kinetics, adsorption capacity and transport behavior of CH4 was studied in batch experiments and in a fixed-bed column by varying the biochar and compost mixtures under 5-levels, 3 different water contents (dry, 15% and 30% water holding capacity), and 2 inlet flow rates. Experimental results were formally tested using analysis of variance (ANOVA) in order to draw objective conclusions based on statistical inference. As CH4 biofiltration requires water addition to maintain microbial activity, these results indicate adsorption capacity is not lost with water addition if biochar content is the dominant packing material. The Langmuir isotherm described the data best (R2 = 0.99). Maximum adsorption capacity by monolayer adsorption, or qmax, is relatively similar with or without the addition of water as long as the biochar component is the dominant material at 3.5 mg CH4/g medium for a 7:1 biochar: compost, v/v mixture. Empirical regression models for qo, kTh, (Thomas model) and τ and KYN (Yoon-Nelson model) were developed for the break through curves of CH4. The current work demonstrates the applicability of utilizing biochar, a relatively inexpensive adsorbent, can compensate for the low solubility of CH4 and overcome the rate-limiting step of mass transfer from the gas phase and into the methanotrophic biofilm. Further, biochar may be a reliable back-up system for CH4 storage especially for fluctuating inlet loads that may be encountered in industrial applications adsorbing up to 13 mg CH4/g biochar under dry conditions.

Potentials of cocoa pod husk-based compost on Phytophthora pod rot disease suppression, soil fertility, and Theobroma cacao L. growth.

Cocoa black pod disease caused by Phytophthora megakarya and reduced soil fertility are major constraints to cocoa production resulting in high yield losses. In the absence of effective control measures and constraints related to the use of chemical fungicides and fertilizers, there is a need to develop additional and sustainable disease and fertilization management strategies. With the lack of studies related to the use of compost in cocoa cultivation, the present study aims to evaluate the potential of cocoa pod husk (CPH)-based compost as a soil amendment to reduce the severity of cocoa black pod disease and enhance plant growth. In vitro antagonism test showed that compost water extracts (CWE) reduced mycelial growth with inhibition rate reaching 100% associated with microorganisms. Disease score of cocoa plantlets grown on compost-amended soils significantly reduced compared to plantlets grown on non-amended soil (control). All compost rates tested significantly increased populations of actinomycetes and fungi and biological activity in the soil. Compost application increased soil pH and majority of the essential elements but decreased Al content, which is toxic to cocoa growth in acidic soils. Soil application of compost at the dose of 20% (v/v) significantly increased stem length and number of leaves compared to the control. This study shows that CPH-based compost can not only improve soil fertility and cocoa growth but also reduce cocoa black pod disease severity by direct effects on inoculums level in the soil and by inducing resistance in the plant.

Effect of Broiler Slaughter Waste Compost on Seed Germination and Growth Performance of Selected Crop Plants

Organic farming is a global trend in green economy. Composting has been promoted as a organic farming method and waste management technique. It has been reported that raw compost made of municipal solid waste (MSW) lacks essential macro and micro nutrients. Slaughter House Waste (SHW) which generally is a cause of concern in waste management is a good source of nutrients. This study was aimed at evaluating growth performance of plants applied with a combination of MSW and SHW. Open windrow method was used to prepare the mixture made of 80% MSW and 20% SHW. In vitro seed germination was tested using the compost suspension and distilled water (as the control). A 1:1 combination of Compost and soil was filled into three pots (12 cm diameter) and three green gram seeds were planted in each pot. Another set of three pots was filled with raw compost and in the control, soil was filled into three pots, and three green gram seeds were planted in each pot. The number of germinated seeds was counted and after four weeks the shoot heights, fresh weight and dry weight were measured along with number of leaves of each seedling. A second set of experiments was carried out following the same method with radish seeds. Both green gram and radish seeds showed 100% germination in compost and distilled water. Remarkable increase in root length was observed in compost compared to distilled water. In the pots 100% seed germination occurred in both crops in all three treatments. Plants grown in combination of compost and soil showed higher growth performance with more leaves, higher shoot length and higher fresh and dry weights than plants grown in 100% soil medium. However, poor growth was observed in plants grown in raw compost alone. Results revealed that compost with slaughterhouse waste is an effective organic fertilizer for test crops. The nutrients lacking compost made of just MSW can be improved to a high quality fertilizer by adding SHW. However, compost made of MSW and SHW alone is not suitable for planting crops but this could be used by mixing with soil. Keywords: Compost, Seed germination, Slaughterhouse waste

Suppressive effect of composts from residual biomass on Pythium ultimum

Two experiments were established in the laboratory of the Department of Organic Farming and Cropping Systems and the greenhouse of the University of Kassel, Germany, in 2017. The experiments studied the suppressive effects of three composts: 1. household-waste compost (HC); 2. spent mushroom compost (SMC); and 3. vermicompost (VC) against Pythium ultimum on pea. For in vitro experiment, two different incubation periods for every compost extract (7 and 14 days) and tap water as control were established. All composts had a suppressive effect on the pathogen, and HC had the most limiting effect on the mycelium. HC suppressed the mycelium disk up to 34 mm, while SMC, VC and control showed 46, 64 and 106 mm mycelium inhibition, respectively. This experiment showed that a higher percentage of composts have significantly more liming effect on P. ultimum. Moreover, longer extraction time had significantly less suppressive effect on P. ultimum. The infection index for pots with 1% infection was not significantly different between VC (1.4) and HC (1.7); however, SMC (2.2) was significantly less suppressive. This work demonstrates that all composts are suppressive against P. ultimum, though SMC had significant difference toward the infection index by the control treatment in both infection levels.

Leaching characteristic of toxic trace elements in soils amended by sewage sludge compost: A comparison of field and laboratory investigations

A 3-years field test and laboratory leaching test have been conducted to assess the environmental impact of land application of sewage sludge compost in conjunction with wheat and rice crops. Considering the complexity and variability of field conditions, we compared the result of laboratory test with the field test to understand the accuracy and uncertainty associated with using the laboratory test to evaluate the field scenario. The laboratory test with cycling of compost additions and water percolation was a high time-efficient and feasible method to simulate the annually repeated additions of compost in the field application scenario. The results of laboratory test were congruent to the 3-years field test regarding the leaching characteristics and geochemical speciation of toxic trace elements. Both the laboratory and the field test showed that repeated additions of compost to soils can increase leaching concentrations of toxic trace elements at neutral to alkaline pH. Increased toxic trace elements leaching was caused by the increase of organic matter from compost application and organic matter dissolution at alkaline pH. Uncertainties of the laboratory test mainly included the negligibility of crop growth and the strongly reducing condition formed with continuous percolation procedure.

Use of a germination bioassay to test compost maturity in Tekelan Village

Livestock waste from cattle farms in Tekelan village, Getasan Subdistrict, Semarang Regency can be grouped into three types, namely solid waste, slurry and waste water. Solid waste (cow dung) was processed into compost, while slurry and waste water were used to make liquid fertilizer. This compost was used as a component of planting media in horticultural crops and potted plants production. We evaluated the toxicity (phytochemical and ecotoxicological) test of compost by using germination index (GI). Vigna radiata seeds are sown on filter paper dampened with compost extract for different times. GI was calculated by relative germination (G) and relative radical length (L). The germination index (GI) = G / G0 x L / L0 x 100, where G0 and L0 are values obtained by distilled water as a control. The results showed that germination bioassay and radical length using aquades and groundwater in Tekelan village did not affect the radical length of Vigna radiata . Technically, groundwater in Tekelan village can be used as a germination bioassay control. The cow dung compost substrate appears to have a major influence on compost toxicity. Mature compost was produced on day 14 with a GI of 104.03.

The effect of wet compost extract on the root tubers of green pea

Nitrogen plays significant role in the life of plants, it could be the main limiting factor of plant growth. Sustainable plant nutrition pays attention to satisfy the plants’ nutrient demand without chemical fertilizers, e.g. by bounding the atmospheric nitrogen. The nitrogen fixing organizations play important role in supplying plants with nitrogenbecause the N2-fixingbacteria can fix high amounts of nitrogen.Many effects of the sewage sludge compost extracts is known in the literature. We studied the effect of sewage sludge compost water extract in laboratory conditions on the growth of Rhizobium spp. isolated from green pea, while in a small plot experiment thepea-Rhizobium symbiosis were studied on sandy soil in the Nyírség region. The extract was produced under aerobic conditions. The compost extract was applied before and/or after sowing. In the laboratory experiments we used the sterile version of extract, in different doses.In our work we present the effect of compost water extract on the number of green pea roots nodules, dry weight of the plant and reproduction of the Rhizobium bacteria.

Disintegration in Compost Conditions and Water Uptake of Green Composites from Poly(Lactic Acid) and Hazelnut Shell Flour

Green composites of poly(lactic acid)-PLA and hazelnut shell flour (HSF) with and without epoxidized linseed oil (ELO) as plasticizer/compatibilizer were subjected to different aging conditions such as water uptake by immersion and disintegration in compost soil. The effect of the hydrolytic degradation was analyzed by measuring the weight gain as a function of the immersion time in water and calculating the corresponding diffusion coefficients. As expected, the water diffusion coefficient increases with HSF content while no remarkable change is obtained for plasticized compositions with ELO. Differential scanning calorimetry reveals a noticeable increase in crystallinity after the degradation process by water immersion. Degradation in controlled compost soil was followed thorough measurements of weight changes. In general, the weight change for a particular degradation time is lower as the HSF content increases. In addition, presence of ELO as plasticizer/compatibilizer delays the degradation process in compost soil. Scanning electron microscopy highlighted a noticeable deterioration of aged samples after 2 weeks with multiple crack formation and high surface abrasion due to microbial activity after 4 weeks.

“Biodegradable” Plastics: A Myth of Marketing?

When compared to their petroleum based counterparts, bioplastics can be biodegradable, sustainable, more environmentally friendly (lower greenhouse gas emissions and fossil fuel usage) and/or should be a renewable option to plastic product production. Despite certain limitations, bioplastics remain a front runner as a suitable replacement for petroleum based plastics. This study aimed at investigating the biodegradability of bioplastic vs. petroleum based plastic under various conditions.This experiment focused on bioplastic samples retrieved from a frozen yoghurt shop in Chile and its rate of biodegradability under different conditions by varying the temperature, pH and environment. A comparison was drawn between the bioplastic samples and petroleum based plastic samples with both sets being subjected to the same conditions. The spoons were subjected to three temperatures and seven different media (NaOH, NH3, compost, Air, HCl, CH3CHOOH and pond water) to determine their biodegradability.Subsequent to exposing the available bioplastic to different conditions by varying the temperature, pH and nature of the environment, the bioplastic samples did not biodegrade but gained weight. These results were surprising, and were similar to that of the petroleum based plastics under the same conditions. This similarity could lead one to deduce that bioplastic samples labelled as such may in fact not be made from biological sources.

Use of composted agro-energy co-products and agricultural residues against soil-borne pathogens in horticultural soil-less systems

One feedstock of composted agro-energy co-products and agricultural residues was physically-chemically-microbiologically characterized and investigated for the phytotoxic property and the disease suppression for finding next-generation “green composts” suitable for use in horticultural soil-less systems. The suppression of three composts made of crude steam-explosion liquid-waste of miscanthus (SELWM), giant reed (SELWA) and wheat straw (SELWWS) mixed with the agro-waste mostly available in Southern Italy [CWS (SELWWS+woodchip+tomato-waste),CM (SELWM+coffee-ground+artichoke-waste) and CA (SELWA+defatted olive marc+fennel-waste)] was tested by the in vitro and in vivo experiments against seven horticultural pathosystems (Phytium ultimum/Cucumber, Phytophthora nicotianae/Tomato, Rhizoctonia solani/Bean, Sclerotinia sclerotiorum/Lettuce, Fusarium oxysporum f. sp. melonis/Melon, Fusarium oxysporum f. sp. lycopersici/Tomato,and Verticillium dahliae/Eggplant). One compost (CC) sourced from the differentiated municipal bio-waste with pathogen-specific property was employed as reference. The phytotoxicity of composts was assessed on lettuce and cress. In vitro bioassays carried out on pure colonies showed that raw compost water extracts (CWEs) were able to inhibit all of pathogens adopting a pouring technique, and that a well-cut diffusion method allowed the block of growth of the pathogens without physical interaction with compost microflora. The sterile-filtration of CWEs annulled inhibition of the pathogens, but S. sclerotiorum and V. dahliae were inhibited by sterile CWEs using a pouring procedure. In vivo tests performed under greenhouse conditions using peat-based plant growing media amended with each compost at dosage of 20% (v/v) showed multi-suppressive activity: CWS suppressed most efficiently P. ultimum, R. solani, P. nicotianae, F. oxysporum f. sp. melonis, F. oxysporum f. sp. lycopersici, V. dahliae; CM was capable to suppress P. ultimum, R. solani, P. nicotianae, S. sclerotiorum, V. dahliae; CA was suppressive against R. solani, P. nicotianae, V. dahliae. The microbiological inactivation of composts by heating treatment reduced suppression in all of pathosystems, but for S. sclerotiorum/Lettuce and V. dahliae/Eggplant the loss of suppressivity was smaller in CA, CM and CC. The predictive parameters to suppression were different: total fungal biomass for P. nicotianae; FDAH for P. ultimum; Trichoderma for R. solani; Aspergillus, Pseudomonas and Streptomyces for F. oxysporum. Instead, the parameters that drive suppression of S. sclerotiorum and V. dahliae were not well cleared. The use of composted agro-waste seems to be an efficient alternative to peat-based substrates for controlling diseases on a broad range of horticultural crops with inappreciable phytotoxic effects if added in moderate dose.

Input and Output Budgets for Nitrogen of Paddy Field in South Korea

The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in paddy field area of South Korea in 2010 and 2013. Input and output budgets for nitrogen were estimated by mass balance approach. The mass balance approach reduces the effect of flow variations, and the large scale approach minimizes local effects, resulting in easier and faster establishment of strategy for nonpoint pollution problems. Nitrogen inputs were chemical fertilizer, compost, atmospheric deposition, biological fixation, and agricultural water, while crop uptake, denitrification, volatilization, and infiltration were nitrogen outputs. The estimated total nitrogen inputs for paddy field in South Korea were 266,211 ton yr -1 , 260,729 ton yr -1 , while those of total nitrogen outputs were 168,463 ton yr -1 , 164,994 ton yr -1 in 2010 and 2013, respectively. Annual amounts of potential nitrogen outflow from paddy field were 97,748 ton yr -1 , 95,735 ton yr -1 in 2010 and 2013. Also, annual rate of potential nitrogen outflow were 36.7%, 36.7% in 2010 and 2013, respectively.

Biodegradation of poly(butylene succinate) film by compost microorganisms and water soluble product impact on mung beans germination

The biodegradation of poly(butylene succinate) (PBS) films by compost microorganisms were studied for insight into the composition of water soluble products and their effect on the surroundings, including medium pH, microorganism viability and mung beans germination. After degradation by compost microorganisms adhering to the film surface, PBS films showed a lot of cracks and holes, accompanied by a continuous decrease of remaining mass and molecular weight. In the initial two weeks, the water soluble products acidified the medium from pH7.2 to pH5.2 and inhibited the microbe growth. With the assimilation of these products as carbon sources by microorganisms, the medium pH value gradually returned to neutral and the microbes fast proliferated as well. The ultra performance liquid chromatography-mass spectrum analysis confirmed that the water soluble products were composed of 1,4-butanediol (B), succinic acid (S), and their oligomers BS, BSB, SBS, BSBS, BSBSB and SBSBS, whose contents depended on their production, microbial assimilation and instability. The germination test revealed that the water soluble products themselves were little hazardous to mung beans, but the acidified medium significantly inhibited the mung beans germination. Fortunately, PBS-degrading microorganisms were able to recover the safe neutral environment by assimilating these acid products.

Integrating liquid fraction of pig manure in the composting process for nutrient recovery and water re-use

Composting of solid fraction of swine manure is a usual practice in most farms in order to obtain a fertilizer of better quality. Due to the negative hydric balance of the composting process, watering the composting material is necessary, what may be carried out with liquid fraction of pig manure. In this way, substantial amounts of liquid fraction can be treated by composting, allowing the recovering the nutrients and reducing the volumes to be transported to the more distant crop fields or subjected to further treatment. Thus, the main objective of this research was to study the treatment of liquid fraction of pig manure by co-composting with solid fraction of pig manure and other solid biowaste generated in rural areas. The present research is part of a project to find an integral solution for pig manure consisting of nutrient recovery through compost production and water re-use after biological purification in constructed wetlands. In accordance with the European waste management hierarchy, sustainable and low cost cleaner technologies aiming at resource recovery must be developed as an alternative to conventional technologies applied to the treatment of pig manure. This paper presents the results of composting of liquid fraction of fresh manure, which is conceived at the same time as a pig wastewater pre-treatment, wastewater volume reduction and a nutrient recovery system. Two 30 m3 turned windrows were constituted with solid fraction of pig manure and Populus sp. wood chips as bulking material at volume ratios of 1:1 and 1:2 and watered intensely with liquid fraction whilst thermophilic temperatures were maintained. Subsequently, both windrows were divided and the new windrows each received the same quantity of a different organic waste (solid fraction of pig manure, sawdust and grape bagasse), being watered with liquid fraction for a further 30 days. Stabilised composts with a nitrogen content ranging from 1.8 to 2.0% and a carbon to nitrogen ratio from 14.0 to 18.8 were obtained. Water balances showed evaporation rates ranging from 14 to 76 L/t total solids·d and overall evaporation ratios from 1 to 2.7 m3/t total solids, referred to dry matter of solid waste. While the reduction of liquid fraction volume ranged from 58 to 88% (depending on the watering rate), mass reduction of pollutants reached approximately 90% of total Kjeldahl nitrogen, ammonium and suspended solids. In comparison with traditional composting processes of solid fraction, our results show that huge amounts of liquid fraction can be treated by co-composting with solid fraction and other solid wastes. Integrating the liquid fraction of pig manure in the composting process has improved the compost quality and has reduced the pollutant load in the remaining liquid fraction, which makes possible an advanced treatment in constructed wetlands in order to reach the necessary water quality to be recycled or even to discharge in natural water bodies. In this way, both composting and constructed wetland systems can offer an integral solution for the recovery of water and fertilizer elements contained in pig manure and diverse locally generated solid wastes. However, in spite of these benefits, more research focussing on nitrogen balances, ammonia volatilisation and greenhouse emissions will be of great interest.

Identification of novel esterase-active enzymes from hot environments by use of the host bacterium Thermus thermophilus

Functional metagenomic screening strategies, which are independent of known sequence information, can lead to the identification of truly novel genes and enzymes. Since E. coli has been used exhaustively for this purpose as a host, it is important to establish alternative expression hosts and to use them for functional metagenomic screening for new enzymes. In this study we show that Thermus thermophilus HB27 is an excellent screening host and can be used as an alternative provider of truly novel biocatalysts. In a previous study we constructed mutant strain BL03 with multiple markerless deletions in genes for major extra- and intracellular lipolytic activities. This esterase-diminished strain was no longer able to grow on defined minimal medium supplemented with tributyrin as the sole carbon source and could be used as a host to screen for metagenomic DNA fragments that could complement growth on tributyrin. Several thousand single fosmid clones from thermophilic metagenomic libraries from heated compost and hot spring water samples were subjected to a comparative screening for esterase activity in both T. thermophilus strain BL03 and E. coli EPI300. We scored a greater number of active esterase clones in the thermophilic bacterium than in the mesophilic E. coli. From several thousand functionally screened clones only two thermostable α/β-fold hydrolase enzymes with high amino acid sequence similarity to already characterized enzymes were identifiable in E. coli. In contrast, five further fosmids were found that conferred lipolytic activities in T. thermophilus only. Four open reading frames (ORFs) were found which did not share significant similarity to known esterase enzymes but contained the conserved GXSXG motif regularly found in lipolytic enzymes. Two of the genes were expressed in both hosts and the novel thermophilic esterases, which based on their primary structures could not be assigned to known esterase or lipase families, were purified and preliminarily characterized. Our work underscores the benefit of using additional screening hosts other than E. coli for the identification of novel biocatalysts with industrial relevance.

Altered carbon delivery from roots: rapid, sustained inhibition of border cell dispersal in response to compost water extracts

Background and aims In a previous study, a compost water extract (CWE) applied to pea seedlings resulted in >95 % protection against root infection. The protection was correlated with retention of a sheath of root border cells surrounding each root tip. A transient exposure to CWE was correlated with 80 % reduction in infection, and with retention of border cell sheaths. Early effects of CWE on border cell dispersal therefore were examined.

Nitrogen compound pollution associated with the use of sewage sludge compost and limestone outcrop residue under saline irrigation

The use of composted sewage sludge and limestone outcrop residue in land rehabilitation, soil improvement, and technosol making can influence the mobility of nitrogen compounds in groundwater. This experiment analyzed this source of possible pollution under an experimental design based on the use of columns (0–30 cm) formed by both wastes and a heavy irrigation regime. Two waters of different quality (saline and non-saline) were used for irrigation. The presence of nitrate, nitrite, and ammonium in the leachates was checked. The environmental risk due to the presence of nitrogen species associated with the use of these materials was very low in general, although nitrate was the most important compound affected by the use of sewage sludge compost and saline water. The combination of saline water for irrigation with the compost has to be seriously considered as a source of pollution for surface and ground waters, and the use of both resources may be a key factor to be studied (low-quality water and sewage sludge compost).

Potato pulp as a composting substrate

Potato pulp is a waste, which is produced in considerable quantities by starch manufacturing industry. Addition of pulp fibre residue to soil results in beneficial effects on soil physical and biochemical properties. In this study, organic potato pulp was mixed with organic grass in three concentrations (75:25 (A), 50:50 (B) and 25:75 (C) % w/w) with the aim of comparing the dynamics of the composting process during a 30-day period. A mini-field experiment was conducted in 0.7 m 3 windrows which were left without covering and additional mixing during composting process, except sampling procedure. During 30-days’ experiment the C:N ratio decreased from 25÷30 to 13÷17 indicating the active conversion of organic matter in windrows with three different combinations of the substrate. An increase of grass concentration led to an increase of the temperature in the windrow at the thermophilic phase of the process. This effect can be explained by higher porosity of the composting substrate containing 75% grass and 25% (w/w) potato pulp. Fourier transform infrared (FT-IR) spectra of compost water extracts indicated the heterogeneity of compost. The water content in two windrows was 59÷75% and 81÷86%, respectively, thus indicating considerable differences in the dynamics of physico-chemical and microbiological processes. The order of earthworms’ preference for compost samples can be listed as follows: A < C < B. Therefore, the ratio potato pulp:grass as 1:1 could be considered as the most optimal under the tested conditions.

Anaerobic thermophiles.

The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has definitely made this area of investigation more exciting. Particularly fascinating are their structural and physiological features allowing them to withstand extremely selective environmental conditions. These properties are often due to specific biomolecules (DNA, lipids, enzymes, osmolites, etc.) that have been studied for years as novel sources for biotechnological applications. In some cases (DNA-polymerase, thermostable enzymes), the search and applications successful exceeded preliminary expectations, but certainly further exploitations are still needed.

Characterizing Water Holding Capacity and Runoff during Composting of Greenwaste and Biosolids

ABSTRACT Most composters in the United States use open-windrows. During high intensity precipitation events, uncontained water running off of the surface of the compost piles can potentially contaminate surface waters with nutrients and metals. Water that is absorbed poses no runoff concern but may threaten groundwater quality. To gain insight into these processes, stormwater runoff fractions and water holding capacity of compost piles have been characterized for greenwaste (GW) and biosolids (BS) materials. Laboratory scale experiments were conducted using days 1, 7, and 14 materials representing three different stages of composting. This study also evaluated sloped and flat-top as different pile geometries and surfactant use for promoting infiltration. Results indicate that fresh materials were most hydrophobic and the infiltration rates increased with increased composting times. The water storage capacity of the compost pile increased with the age of the compost pile. Compost water storage capacities could not be reliably estimated as the difference between field capacity and as-received water contents.