Transformation of Arsenobetaine and Growth of Bacteria on Zeolitic Tuffs

Arsenobetaine (AsB) is a known organoarsenical of harmless toxicity. It is formed mainly by the metabolization of arsenate in marine organisms such as fish, mollusks and crustaceans. Preliminary investigations have shown that AsB can be degraded in contact with zeolites used as feed additives. Employing high‐performance liquid chromatography (HPLC) combined with simultaneous parallel electrospray ionization (ESI) and inductively coupled plasma mass spectrometric (ICP‐MS) detection, the formation of degradation products was monitored over fifty days in batch reactors containing AsB and clinoptilolites in an aqueous solution. After a 50‐day contact with different natural Mexican zeolites, the AsB concentration decreased by 37 to 100 %. In contrast, no degradation products of AsB were detected after contact with a synthetic clinoptilolite. The formation of dimethyl (1‐carboxymethyl) arsine and arsenate proceeded with different yields in the set of four natural zeolites. To search for the presence of bacteria on the zeolites as an alternative explanation for the metabolism of AsB in our experiments, the growth of microorganisms was studied on two natural clinoptilolites from Hungary and Mexico after severe acid wash. After 10 days of cultivation in iron and sulfur media, almost a threefold increase of the microbial population was observed. In further experiments on the retention of inorganic arsenic, one sample retained, for example, 25 μg/g As(V) and 2.5 μg/g As(III) from a 400 μg/L arsenic solution.     

Sawdust and natural zeolite as a bulking agent for improving quality of a composting product from anaerobically stabilized sewage sludge

This study has dealt with the production of compost from dewatered anaerobically stabilized primary sewage sludge (DASPSS) and sawdust (SWD). SWD is added in order to increase the humic substances in the final product. The DASPSS is mixed with clinoptilolite (Cli), which is used as a bulking agent at 20% w/w, and the mixture is amended with sawdust at 10%, 30% and 40% (w/w). The final results have indicated that by increasing the sawdust concentration in the initial mixture, the humic substances in the final product increase too. The natural zeolite that was added in the initial mixture takes up a significant amount of heavy metals. In order to observe the maturity of the final product, the germination index is used in oat cultivation. The results indicate that the substrate appears to be non-phytotoxic after 75 d of maturity. Also, in order to estimate the metal leachability of the final compost product, the generalized acid neutralization capacity procedure is applied, and it is found that by increasing the pH values, the heavy metal concentrations decrease.     

Effects of sulphur and Thiobacillus thioparus on cow manure aerobic composting

A simulated aerobic composting experiment was used to explore the effects of sulphur and Thiobacillusthioparus during six manure composting treatments. The addition of sulphur led to a decrease of the pH level within the range 6-6.3, which was lower than the control treatment (CK). The concentration of ammonium nitrogen in T1 (0.25% sulphur), T2 (0.5% sulphur), T3 (0.25% sulphur + T. thioparus) and T4 (0.5% sulphur + T. thioparus) were much higher than the ammonium N in CK. The results indicated that addition of sulphur could increase the concentration of ammonium N and reduce loss of nitrogen. However, excess sulphur had a negative effect on temperature and GI. Addition of T. thioparus could increase concentration of available S, alleviate these negative influences and reduce compost biological toxicity.     

Evaluating the quality of communities made compost manure in South Africa: a case study of content and sources of metals in compost manure from Thulamela Municipality, Limpopo province

The main aim of this research was to assess the quality of the compost manure of a community project which is part of Government's initiative for job creation. This was done by determining the sources, presence and concentrations of metals in the composting materials and compost manure. Generally, there are many communities involved in making compost manure with no assessment of the quality of the compost. This is because no quality assurance guidelines are in place. The main source of heavy metals in the composting materials was found to be sawdust while cabbage was the main source of the essential nutrient elements such as magnesium calcium and potassium. The level of heavy metals in all the compost materials were found in the following order: Fe>Mn>Cr>Ni>Zn>Cu>Co>Cd. The level of essential elements was in the following order: Ca>Mg>K>S>Na>Li>Si>P. The level of heavy metals in the compost materials reflected the level in the final compost manure. The concentration of metals in the compost materials and compost manure was below the international standards of compost manure. Therefore, compost manure can be said to be of good quality. However, sawdust was found to be not a good compost material as it was the source of main heavy metals.     

Effects of the addition of different nitrogen sources in the tequila fermentation process at high sugar concentration

AIMS: To study the effect of the addition of different nitrogen sources at high sugar concentration in the tequila fermentation process. METHODS AND RESULTS: Fermentations were performed at high sugar concentration (170 g l(-1)) using Agave tequilana Weber blue variety with and without added nitrogen from different sources (ammonium sulfate; glutamic acid; a mixture of ammonium sulfate and amino acids) during the exponential phase of growth. All the additions increased the fermentation rate and alcohol efficiency. The level of synthesis of volatile compounds depended on the source added. The concentration of amyl alcohols and isobutanol were decreased while propanol and acetaldehyde concentration increased. CONCLUSIONS: The most efficient nitrogen sources for fermentation rate were ammonium sulfate and the mixture of ammonium sulfate and amino acids. The level of volatile compounds produced depended upon types of nitrogen. The synthesis of some volatile compounds increased while others decreased with nitrogen addition. SIGNIFICANCE AND IMPACT OF THE STUDY: The addition of nitrogen could be a strategy for improving the fermentation rate and efficiency in the tequila fermentation process at high sugar Agave tequilana concentration. Furthermore, the sensory quality of the final product may change because the synthesis of the volatile compounds is modified.     

Effect of carbide sludge (lime) on bioavailability and leachability of heavy metals during rotary drum composting of water hyacinth

Abstract

The bioavailability and leachability of heavy metals play a major role in the toxicity of heavy metals in the compost applied for soil conditioning. A rotary drum composter was used for the study of heavy metal bioavailability and leachability during water hyacinth composting with a mixture of cattle manure, sawdust and lime. Lime was added in 1, 2 and 3% to the mixture of water hyacinth, cattle manure and sawdust at a ratio of 6:3:1 respectively. Influences of physico-chemical parameters on heavy metal bioavailability and leachability were studied during the process. The bioavailability of heavy metals solubility and diethylene triamine penta-acetic acid extractability was examined. The toxicity characteristics leaching procedure (TCLP) test was performed for assessing the hazardous properties of compost. The nutrients and the total concentration of heavy metals were increased during the composting process. The lime was very effective in reducing water solubility, plant availability and leachability of the selected heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd and Cr) during the process. The addition of lime provided a buffer against the decrease in pH and a sufficient amount of Ca that would improve the metabolic activity during composting. The addition of an excess amount of lime slowed the metabolic activity of the microbes due to its high alkalinity. The TCLP test confirms that the heavy metals concentrations in the control and in the lime-amended compost were below the threshold limits.     

Amending soils of different texture with six compost types: impact on soil nutrient availability, plant growth and nutrient uptake

Background

Composts with different feedstocks may have differential effects on soil properties and plant growth which, may be further modulated by soil texture.

Materials and methods

In a 77-day pot experiment in the glasshouse, we investigated the effect of a single application as mulch of six types of composts derived from different starting feedstocks in two soils (13% and 46% clay, referred to as S13 and S46) on soil physical, chemical and biological properties, plant growth and nutrient uptake. Composts were placed as 2.5?cm thick mulch layer on the soil surface and wheat plants were grown and harvested at 42?days and at 77?days (grain filling).

Results

Composts differed in total and available N and P and particle size with C1, C3, C4 and C5 being fine-textured, whereas C2 and C6 were coarse-textured. Compost addition as mulch increased soil total organic C and EC, but had no effect on pH. In all treatments, cumulative soil respiration was higher in S13 than in S46 and was increased by compost addition with the greatest increase with C2 and C6. Compared to the unamended soil, most compost mulches (except C2) increased macroaggregate stability. Compost mulches significantly increased available P and N in both soils, except for C2. Compost mulches increased available N up to 6-fold in both soils with the strongest increase by C5. Most composts also increased wheat growth and shoot P and N concentrations with the greatest effect on plant N concentration by C5 and on plant P concentration by C4. However, C2 decreased shoot N and P concentrations compared to the unamended soil. Most compost mulches (except C2) increased mycorrhizal colonization by up to 50% compared to the unamended soil.

Conclusions

Fine-textured compost mulches generally had a greater effect on soil properties and plant growth than coarse-textured composts. Despite distinct differences between the soils with respect to clay content, TOC and available P, the effect of the compost mulches on soil and plant properties was quite similar.     

Responses of Wheat Yield,Macro- and Micro-Nutrients,and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn.     

Separation of Alcaligenes eutrophus cells containing Poly(3-hydroxybutyrate) from fermentation broth with pretreatment using Al- and Fe-based coagulants

Alcaligenes eutrophus containing intracellular poly(3-hydroxybutyrate) was recovered from fermentation broth by centrifugation and filtration after pretreatment with Al- and Fe-based coagulants. Coagulation efficiency was largely affected by pH, and the optimum pH's for cell recovery were about 4.6-5.6 for the Al-based coagulants and about 5-8 for the Fe-based coagulants. Ammonium ions that combined with metals to form complex compounds increased the coagulant requirement, and the additional requirement of coagulant was found to be proportional to the ammonium concentration. In addition, various ligands in addition to ammonium ions contained in the culture medium interfered with the coagulation reaction and increased the coagulant requirement also. The coagulant requirement increased with the cell concentration regardless of coagulant type. The polymeric coagulants such as PACS, Hi-PAX, and Ferix-3 were more effective than nonpolymeric coagulants of aluminum sulfate and ferrous sulfate. The optimum dosages of the coagulants tested were determined over a broad range of cell concentration of 20.5-210 g/L. It was observed that the energy requirement for centrifugation could be greatly reduced with cell coagulation.     

Contrasting Effects of Farmyard Manure (FYM) and Compost for Remediation of Metal Contaminated Soil

We investigated effect of farm yard manure (FYM) and compost applied to metal contaminated soil at rate of 1% (FYM-1, compost-1), 2% (FYM-2, compost-2), and 3% (FYM-3, compost-3). FYM significantly (P < 0.001) increased dry weights of shoots and roots while compost increased root dry weight compared to control. Amendments significantly increased nickel (Ni) in shoots and roots of maize except compost applied at 1%. FYM-3 and -1 caused maximum Ni in shoots (11.42 mg kg^?1) and roots (80.92 mg kg^?1), respectively while compost-2 caused maximum Ni (14.08 mg kg^?1) and (163.87 mg kg^?1) in shoots and roots, respectively. Plants grown in pots amended with FYM-2 and compost-1 contained minimum Cu (30.12 and 30.11 mg kg^?1) in shoots, respectively. FYM-2 and compost-2 caused minimum zinc (Zn) (59.08 and 66.0 mg kg^?1) in maize shoots, respectively. FYM-2 caused minimum Mn in maize shoots while compost increased Mn in shoots and roots compared to control. FYM and compost increased the ammonium bicarbonate diethylene triamine penta acetic acid (AB-DTPA) extractable Ni and Mn in the soil and decreased Cu and Zn. Lower remediation factors for all metals with compost indicated that compost was effective to stabilize the metals in soil compared to FYM.     

Determination of a relationship between chitinase activity and microbial diversity in chitin amended compost

By using denaturing gradient gel electrophoresis (DGGE) and simultaneously measuring the enzymatic activity of chitinase, we could link genetic diversity of the indigenous microbial communities with chitinase activity in compost samples. A garden/park waste compost and a source separated organic household waste compost, showed different genetic diversity as measured by PCR-DGGE of total DNA extracted from the composts. The household waste compost had the highest chitinase activity. To increase chitinase activity, the two composts were amended with chitin. This addition induced a change in both the bacterial and fungal genetic diversity when compared to the non-amended compost samples. Likewise, both composts reacted to the addition of chitin with an increase in chitinase activity. Thus, a relationship between genetic diversity and chitinase activity was established for the composts in question. The N-mineralization in the household waste compost was apparently increased by the addition of chitin, while such an effect was not observed in the garden/park waste compost.     

Heavy Metal Accumulation and Ecological Responses of Turfgrass to Rubbish Compost with EDTA Addition

Domestic rubbish compost is a complex-polluted system, containing multiple heavy metals,which limits its application. In the present study, Cr, Mn, Ni, Cu, Zn, Cd, and Pb accumulation and ecological responses of turfgrass to rubbish compost were investigated following the addition of EDTA. The results showed that the addition of EDTA significantly increased heavy metal accumulation in Lolium perenne L.and Festuca arundinacea L. Most heavy metal concentrations in L. perenne increased with increasing EDTA supply. The concentrations of Cr, Mn, Ni, Cu, and Cd in L. perenne were highest following the addition of 30 mmol/kg EDTA and the concentrations of Cr and Ni at this point reached concentrations of1914.17 and 521.25 μg/g, respectively. When the EDTA level was ＜ 20 mmol/kg, the accumulation of most heavy metals in F. arundinacea increased with increasing EDTA supply, but showed a tendency to decrease at EDTA concentrations ＞20 mmol/kg. The highest concentrations of Mn, Ni, Cu, and Zn in F.arundinacea reached 268.01, 110.94, 161.52 and 1 354.97 μg/g, respectively, following the addition of 20mmol/kg EDTA. The EDTA-induced increase in the accumulation of heavy metals in turfgrass was plantand metal-specific. L. perenne had a relatively high ability to accumulate Cr, Ni, and Zn. The highest Zn concentration was 2 979.58 μg/g and, following the addition of EDTA, the concentrations of the three metals were increased 26.23, 20.03, and 10.49-fold, respectively, compared with control. However, F. arundinacea showed a high ability to accumulate Cr, with the highest concentration (596.02 μg/g) seen following the addition of 30 mmol/kg EDTA; the concentration of Cr increased 15.51-fold compared with control. With EDTA addition, ecological responses of both turfgrass species showed that EDTA at concentrations ＜10mmol/kg increased seed germination and aboveground net primary production (ANP) of L. perenne and slightly inhibited those of F.arundinacea, but EDTA at concentrations ＞20 mmol/kg inhibited these parameters significantly for both species. Moreover, EDTA increased the chlorophyll and proline content at all concentrations tested. On the basis of the synthetic remediation index, the optimal EDTA concentration for turfgrass remediation of heavy metals in compost is approximately 10 mmol/kg.     

Composting of olive leaves and pomace from a three-phase olive mill plant

The composting of olive leaves and olive pomace from a three-phase olive mill was tested as a method for solid waste reuse. The process was carried out using a compost windrow and mixing olive leaves and pomace at a ratio of 1:2. Compost was retained in the windrow for 60 days during which thermophilic temperatures developed for the first 40 days. The compost was then placed into a closed area to mature for another 60 days. The final product proved to be high quality amendment with C/N 27.1 and high nutrient concentrations (N, 1.79%; P, 0.17%; K, 4.97%; Na, 2.8%). Mature compost presented the highest germination index (198%) reported to date, as the germination index in the majority of previous studies is under 80%. Furthermore, tests revealed that addition of 31.5 tons of compost per ha, could increase lettuce yield by 145%.     

Improving the quality of municipal organic waste compost

The effects of different municipal organic waste (MOW) management practices (shredding, addition of carbon-rich materials and inoculation with earthworms) on organic matter stabilization and compost quality were studied. Four static piles were prepared with: (i) shredded MOW; (ii) shredded MOW+woodshavings; (iii) non-shredded MOW; and (iv) non-shredded MOW+woodshavings. After 50 days, a part of each pile was separated for vermistabilization, while the rest continued as traditional thermophilic composting piles. At different sampling dates, and in the finished products, the following parameters were measured: pH, electrical conductivity, carbon dioxide evolution, and concentrations of organic matter, total nitrogen, water-soluble carbon, nitrate nitrogen, ammonium nitrogen, and extractable phosphorus. Shredded treatments exhibited faster organic matter stabilization than non-shredded treatments, evidenced specially by earlier stabilization of carbon dioxide production and shorter thermophilic phases. Woodshavings addition greatly increased quality of final products in terms of organic matter concentration, and pH and electrical conductivity values, but decreased total nitrogen and available nutrient concentrations. Vermicomposting of previously composted material led to products richer in organic matter, total nitrogen, and available nutrient concentrations than composting only, probably due to the coupled effect of earthworm activity and a shorter thermophilic phase.     

The use of sewage sludge and horticultural waste to develop artificial soil for plant cultivation in Singapore

Greenhouse pot experiments were performed with Ipomoea aquatica (Kang Kong) to evaluate artificial soil produced from poor fertility subsoil, horticultural compost, and sewage sludge. The addition of horticultural compost and sewage sludge to subsoil substantially improved plant growth, improved the physical properties of subsoil and enriched subsoil by essential nutrients for plants. The effect was enhanced when the two ingredients were added to subsoil together. The highest yield of biomass of I. aquatica was observed in artificial soil prepared by mixing subsoil with 4% (wet weight/wet weight) of horticultural compost and 2% (dry weight/wet weight) of sewage sludge. The contents of heavy metals in plants, grown in the artificial soil, were significantly lower than toxic levels. The artificial soil could be recommended for urban landscaping and gardening in Singapore.     

Gametocytogenesis induction by ammonium compounds in cultured Plasmodium falciparum

Asexual parasites of a strain that seldom or never produce gametocytes in in vitro culture began gametocytogenesis after 24 h treatment with RPMI 1640 medium containing concanavalin A (final concentration, 10 micrograms ml-1) and ammonium carbonate (final concentration, 15 mM ml-1) or ammonium bicarbonate (final concentration, 15 mM ml-1). Gametocytogenesis was consistently observed from the 3rd day after the treatment. Concanavalin A enhanced gametocytogenesis induction by ammonium carbonate or ammonium bicarbonate, although concanavalin A does not itself have gametocytogenesis induction activity. Whereas no gametocytogenesis was observed after addition of concanavalin A and ammonium acetate (final concentration, 5-25 mM ml-1) or ammonium chloride (final concentration, 5-15 mM-1). Addition of ammonium compounds resulted in decrease of parasitemia, regardless of gametocytogenesis.     

Citrate, a possible precursor of astaxanthin in Phaffia rhodozyma: influence of varying levels of ammonium, phosphate and citrate in a chemically defined medium.

The influence of ammonium, phosphate and citrate on astaxanthin production by the yeast Phaffia rhodozyma was investigated. The astaxanthin content in cells and the final astaxanthin concentration increased upon reduction of ammonium from 61 mM to 12.9 mM (from 140 microg/g to 230 microg/g and 1.2 microg/ml to 2.3 microg/ml, respectively). Similarly, both the astaxanthin content and astaxanthin concentration increased by reducing phosphate from 4.8 mM to 0.65 mM (160 microg/g to 215 microg/g and 1.7 microg/ml to 2.4 microg/ml, respectively). Low concentrations of ammonium or phosphate also increased the fatty acid content in cells. By analogy with lipid synthesis in other oleaginous yeasts, an examination of the data for varying nitrogen and phosphate levels suggested that citrate could be the source of carbon for fatty acids and carotenoid synthesis. Supporting this possibility was the fact that supplementation of citrate in the medium at levels of 28 mM or higher notably increased the final pigment concentration and pigment content in cells. Increased carotenoid synthesis at low ammonium or phosphate levels, and stimulation by citrate were both paralleled by decreased protein synthesis. This suggested that restriction of protein synthesis could play an important role in carotenoid synthesis by P. rhodozyma.     

好氧高温猪粪堆肥中重金属砷、铜、锌的形态变化及钝化剂的影响

采用连续提取法研究了猪粪好氧堆肥处理中重金属浓度和形态的变化以及添加不同比例的重金属钝化剂对其浓度和形态的影响.结果表明：经过堆肥处理后,猪粪中重金属As、Cu和Zn的总浓度均有所增加.从重金属结合形态的变化来看,可交换态As和Zn含量降低,残渣态As和Zn含量升高,表明As和Zn存在着向有效性相对较低的形态转化的趋势;重金属Cu则表现出不同的变化趋势,即可交换态与残渣态Cu含量下降,而碳酸盐结合态、铁锰结合态及有机结合态Cu含量有所增加,在今后的堆肥利用中应注意其可能带来的环境风险;3种重金属钝化剂及不同添加比例的处理中,5.0%的海泡石和2.5%的膨润土分别对重金属As、Zn表现出较好的钝化效果,堆肥后残渣态As和Zn的增幅分别达到79.8%和158.6%,均高于不加钝化剂处理.与对照相比,堆肥后7.5%的海泡石对残渣态Cu的降低幅度最小,为39.3%.猪粪堆肥中添加适量的重金属钝化剂,可以在一定程度上降低重金属的有效性以及猪粪堆肥利用中重金属污染的风险.     

Composting of bio-waste, aerobic and anaerobic sludges--effect of feedstock on the process and quality of compost

In-vessel composting of three stocks with originally different degree of organic matter degradation was conducted for: (1) kitchen source-separated bio-waste (BW), (2) aerobic (AS) as well as (3) anaerobic sludges (AnS) from municipal wastewater treatment plant. Composting experiment lasted over a year. The highest activity of the process was in the BW compost. It was implied by the highest temperature, CO(2) release, ammonification and nitrification, intensive accumulation and removal of low-weight carboxylic acids (water- and NaOH-extractable). Between the sludges higher mineralization and CO2 release was in AnS, while ammonification and nitrification were higher in AS compost; no significant difference between sludge composts was noticed for dynamics of pH, conductivity, concentrations of LWCA, and some nutrient compounds and heavy metals. Nitrogen content of the final compost increased in BW, but decreased in AS and AnS. Phytotoxicity of Lepidium sativum was eliminated faster in sludge composts compared to BW compost.     

Immobilization and phytoavailability of cadmium in variable charge soils. III. Effect of biosolid compost addition

We examined the effect of biosolid compost on the adsorption and complexation of cadmium (Cd) in two soils (Egmont and Manawatu) which varied in their organic matter content. The effect of biosolid compost on the uptake of Cd from the Manawatu soil, treated with various levels of Cd (0–10 mg Cd kg^–1 soil), was also examined using mustard (Brassica juncea L.) plants. The transformation of Cd in soil was evaluated by a chemical fractionation scheme. Addition of biosolid compost increased negative charge in soil. The effect of biosolid compost on Cd adsorption varied between the soils, with a large portion of the sorbed Cd remaining in solution as an organic complex. Increasing addition of Cd increased Cd concentration in plants, resulting in decreased plant growth at high levels of Cd (i.e., phytotoxicity). Addition of biosolid compost was effective in reducing the phytotoxicity of Cd as indicated by the decrease in the concentration of NH₄OAc extractable-Cd and soil solution-Cd. The solid-phase fractionation study indicated that the addition of biosolid compost decreased the concentration of the soluble and exchangeable Cd fraction but increased the concentration of organic-bound Cd fraction in soil. Alleviation of Cd phytotoxicity by biosolid compost can be attributed primarily to complexation of Cd by the organic matter in the biosolid compost.