Detection of Escherichia coli in a cattle manure composting process by selective cultivation and colony polymerase chain reaction

Livestock manure is suitable for use as a composting material. However, various intestinal microbes, such as Escherichia coli, are significant components of such manures. Thus, it is desirable that the level of intestinal microbes, and particularly opportunistic pathogens, in compost is inspected and counted regularly. The sensitivity and specificity of detection of E. coli in compost have been improved by selective cultivation followed by colony polymerase chain reaction (PCR) using the ECO primer. Indeed, the sensitivity of this method is higher than that of DNA extraction from compost and PCR. In this study, changes in numbers of E. coli present in a field-scale composting process over time was assessed using selective cultivation and colony PCR. Numbers of ECO-positive colonies after 24 h decreased, with a concomitant rise in compost temperature. ECO-positive colonies were not detected from 33 to 48 h. However, ECO-positive colony numbers increased beginning on day 4 and continuing until day 42. Thus, it seems likely that the high temperatures reached during the composting process did not affect E. coli numbers in the final compost. Additionally, selective cultivation followed by colony PCR using specific primers is an appropriate method of determining levels of cultivable pathogens in composted materials.     

Municipal waste compost as an alternative to cattle manure for supplying potassium to lowland rice

The importance of the use of potassium in agriculture is increasing in South Asia for making most productive use of the nutrient in terms of economic returns. Nutrient supply traditionally by cattle manure is constrained by its insufficient availability. Municipal waste compost may be an alternative source of nutrient supplements. Field experiments were conducted at the Experimental Farm of Calcutta University, West Bengal, India during the wet seasons of 1997, 1998 and 1999 on flooded lowland rice. Potassium fractions in municipal waste compost and cattle manure were determined by sequential extraction and also the potassium uptake by rice to compare the effectiveness of municipal waste compost with traditional manure. Potassium was significantly bound to the organic matter in municipal waste compost. Potassium uptake by rice grain and straw increased significantly with the combined application of organics and fertilizers and it was higher in grain than in straw. Water-soluble and non-exchangeable potassium contents of municipal waste compost and cattle manure were highly correlated with the uptake of potassium by straw and grain. Exchangeable and residual potassium were also significantly correlated with the uptake of potassium by straw and grain of rice. Much higher uptake of K in rice straw and rain resulted from applying the manures in conjunction with fertilizers than when applied singly.     

Detection of Escherichia coli in a cattle manure composting process by selective cultivation and colony polymerase chain reaction

Livestock manure is suitable for use as a composting material. However, various intestinal microbes, such as Escherichia coli, are significant components of such manures. Thus, it is desirable that the level of intestinal microbes, and particularly opportunistic pathogens, in compost is inspected and counted regularly. The sensitivity and specificity of detection of E. coli in compost have been improved by selective cultivation followed by colony polymerase chain reaction (PCR) using the ECO primer. Indeed, the sensitivity of this method is higher than that of DNA extraction from compost and PCR. In this study, changes in numbers of E. coli present in a field-scale composting process over time was assessed using selective cultivation and colony PCR. Numbers of ECO-positive colonies after 24 h decreased, with a concomitant rise in compost temperature. ECO-positive colonies were not detected from 33 to 48 h. However, ECO-positive colony numbers increased beginning on day 4 and continuing until day 42. Thus, it seems likely that the high temperatures reached during the composting process did not affect E. coli numbers in the final compost. Additionally, selective cultivation followed by colony PCR using specific primers is an appropriate method of determining levels of cultivable pathogens in composted materials.     

Evaluating carbon emissions of China’s waste management strategies for building refurbishment projects: contributing to a circular economy

This study evaluates carbon emissions of construction and demolition (C&D) waste generated by building refurbishment, using a life cycle assessment approach through a case study project in China. Three waste management scenarios were developed for a building refurbishment project in the city of Suzhou. Scenario 1 is under the business-as-usual C&D waste management practice in China; scenario 2 is based on the open-ended 3R strategy, which focuses on the downstream impact of waste; and scenario 3 considers both the upstream and downstream impact of waste. The results reveal that the composition of the waste generated from building refurbishment projects is different from construction and demolition projects. In the life cycle of C&D waste management of building refurbishment projects, the refurbishment material stage generates the highest carbon emissions compared to the dismantlement, refurbishment construction, and refurbishment material end of life stages. Scenario 1 produces higher carbon emissions than scenario 2, but the difference is not significant in the whole life cycle of the building refurbishment project, whereas carbon emissions for scenario 3 are significantly less than both scenario 1 and scenario 2. The study finds the reason for this difference is that scenario 1 and scenario 2 are based on a linear economy that relies on unsustainable demand for raw materials, whereas scenario 3 is based on a circular economy that uses upcycled materials to substitute for raw materials and considers waste management from a cradle to cradle perspective. This study fills a research gap by evaluating carbon emissions of different waste management strategies for building refurbishment projects, which are expected to be an increasing portion of overall construction activity in China for the foreseeable future.

     

The fate of the recombinant DNA in corn during composting

In order to make regulations that safeguard food and the environment, an understanding of the fate oftransgenes from genetically modified (GM) plants is of crucial importance. A compost experiment including mature transgenic corn plants and seeds of event Bt 176 (Zea mays L.) was conducted to trace the fate of the transgene cryIA(b) during the period of composting. In bin 1, shredded corn plants including seeds were composted above a layer of cow manure and samples from the corn layer were collected at intervals during a 12-month period. The samples were tested for the transgene persistence and microbial counts and also the compost was monitored for temperature. In bin 2, piles of corn seeds, surrounded by sheep manure and straw, were composted for 12 months. A method combining nested polymerase chain reaction (PCR) and southern hybridization was developed for detection of the transgene in compost. The detection sensitivity was 200 copies of the transgene per gram of dry composted corn material. Composting commenced on day 0, and the transgene was detected in specimens from bin 1 on days 0 and 7 but not on day 14 or thereafter. The transgene in corn seeds was not detectable after 12 months of composting in bin 2. Temperatures in both bins rose to about 50 degrees C within 2 weeks and remained above that temperature for about 3 months, even when the ambient temperature dropped below -20 degrees C. Extracts from compost were inoculated onto culture plates and then were incubated at 23 to 55 degrees C. Within the first 2 weeks of composting in bin 1, the counts of bacteria incubated at 55 degrees C increased from 3.5 to 7.5 log10, whereas those incubated at 23 degrees C remained at about 7.5 log10. The counts of fungi incubated at 45 degrees C increased slightly from 2.5 to 3.1 log10, but those incubated at 23 degrees C decreased from 6.3 to 3.0 log10. The rapid degradation of the transgene during composting of Bt corn plants suggested that the composting process could be used for safe disposal of transgenic plant wastes.     

The Fate of the Recombinant DNA in Corn During Composting

Abstract

In order to make regulations that safeguard food and the environment, an understanding of the fate of transgenes from genetically modified (GM) plants is of crucial importance. A compost experiment including mature transgenic corn plants and seeds of event Bt 176 (Zea mays L.) was conducted to trace the fate of the transgene cryIA(b) during the period of composting. In bin 1, shredded corn plants including seeds were composted above a layer of cow manure and samples from the corn layer were collected at intervals during a 12-month period. The samples were tested for the transgene persistence and microbial counts and also the compost was monitored for temperature. In bin 2, piles of corn seeds, surrounded by sheep manure and straw, were composted for 12 months. A method combining nested polymerase chain reaction (PCR) and southern hybridization was developed for detection of the transgene in compost. The detection sensitivity was 200 copies of the transgene per gram of dry composted corn material. Composting commenced on day 0, and the transgene was detected in specimens from bin 1 on days 0 and 7 but not on day 14 or thereafter. The transgene in corn seeds was not detectable after 12 months of composting in bin 2. Temperatures in both bins rose to about 50°C within 2 weeks and remained above that temperature for about 3 months, even when the ambient temperature dropped below ?20°C. Extracts from compost were inoculated onto culture plates and then were incubated at 23 to 55°C. Within the first 2 weeks of composting in bin 1, the counts of bacteria incubated at 55°C increased from 3.5 to 7.5 log ₁₀, whereas those incubated at 23°C remained at about 7.5 log ₁₀. The counts of fungi incubated at 45°C increased slightly from 2.5 to 3.1 log₁₀, but those incubated at 23°C decreased from 6.3 to 3.0 log ₁₀. The rapid degradation of the transgene during composting of Bt corn plants suggested that the composting process could be used for safe disposal of transgenic plant wastes.     

Formation of chloromethoxybenzaldehyde during composting of organic household waste

Standardized household waste was mixed with different litter amendments, straw, leaves, hardwood shavings, softwood shavings, paper, and sphagnum peat, resulting in six compost mixtures. In addition non-amended household waste was composted. Composting was done in small rotatable bins and compost samples were taken on a regular basis until day 590. Extraction and analysis of wet compost samples showed no evidence for the presence of chloroorganic compounds. Drying and re-wetting of compost samples, however, revealed that chloromethoxybenzaldehyde (CMBA) was formed in all composts at concentrations varying between 5.6 and 73.4 microg kg(-1) dry matter. CMBA was not present in the original materials. During composting, there was a clear positive relation between formation of CMBA and microbial activity, as indicated by C losses and temperature. Formation took place during the most intensive phase of composting when C losses were highest. Under anaerobic conditions, however, which prevailed initially in the non-amended compost, no CMBA was formed. Calculation of total amounts of CMBA in composts revealed that there was a small decrease during storage in the hardwood, peat, and softwood composts. However, all composts contained CMBA after 590 days. The mean concentration was 33.4 microg kg(-1) dry matter (s.d. = 21.9). Possible biocidal effects of composts when used in cultivation may be explainable by the presence of natural toxic compounds formed during composting.     

The fate of 14C-diazinon in compost, compost-amended soil, and uptake by earthworms

A process for disposing of pesticide rinsates using sorption onto organic matter followed by composting is being evaluated. As a part of this evaluation process, we have studied the bioavailability of composted delta-2-14C-diazinon and its degradation products to earthworms (Eisenia foetida Savigny) in 30 and 60 d compost amended soil. After 60 d of composting there was considerable degradation of diazinon (95%) and a corresponding increase in the primary hydrolysis product, 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMHP) as determined by high performance thin layer chromatography (HPTLC). Approximately 50% of the radioactivity became incorporated into the non-extractable fractions associated with composted organic matter with no measurable amounts of 14CO2 produced during the 60-day composting period. Following addition of the composted materials to soil, diazinon leading to 50% mortality after 14 d of exposure; continued to slowly degrade and become increasingly sorbed/entrapped within the soil-compost matrix. Soil amended with 30-d composted diazinon was toxic to earthworms whereas, no mortality was observed in those earthworms exposed to the 60-d composted diazinon. However, earthworms exposed to 30-d and 60-d composted diazinon were found to have similar levels of radioactivity in their tissues. The majority of the radioactivity in earthworms exposed 60-d composted diazinon was either unextractably bound within the earthworm tissue or was not acetone soluble. Most of the radioactivity that could be extracted with acetone was not separated by the two HPTLC methods we used. This study demonstrates that composting high concentrations of diazinon can greatly reduce toxicity and the amount of diazinon that is bioavailable to a representative soil macroinvertebrate (E. foetida).     

Evaluating landfill disposal of chromated copper arsenate (CCA) treated wood and potential effects on groundwater: evidence from Florida

Chromated copper arsenate (CCA) treated wood has been used for more than 50 years. Recent attention has been focused on appropriate disposal of CCA-treated wood when its service life ends. Groups in the US and Europe concerned with the possibility of arsenic migration to groundwater from disposed CCA-treated wood have proposed that consumers be required to dispose of the wood as a hazardous waste, in the most protective of landfills. We examined available data for evidence of arsenic migration from unlined construction and demolition (C&D) debris landfills in Florida, where CCA-treated wood is disposed. Florida was chosen because soil, groundwater, landfill design, weather, and levels of CCA-treated wood use make the state a uniquely sensitive indicator for observing arsenic migration from CCA-treated wood disposal sites, should it occur. We developed and quality-checked a CCA-treated wood disposal model to estimate the amount of wood and associated arsenic disposed. By 2000, an estimated 13 million kg of arsenic in CCA-treated wood was disposed in Florida; however, groundwater monitoring data do not indicate that arsenic is migrating from unlined C&D landfills. Our results provide evidence that highly stringent regulation of CCA-treated wood disposal, such as treatment as a hazardous waste, is unnecessary.     

水葫芦与厨余垃圾混合好氧堆肥中氮素变化及对腐熟度的影响

通过采用间歇式好氧动态堆肥工艺,对厨余垃圾与添加水葫芦的厨余垃圾进行堆肥实验,探讨堆肥进程中全氮、氨基酸态氮、蛋白质的变化及对腐熟度的影响。结果表明,全氮含量在堆肥后期有所提高,分别由1.76%和2.23%提高到3.64%和2.67%;氨基酸态氮含量与微生物活性显著负相关;添加水葫芦使堆体温度提高,促进了蛋白质的快速降解;堆肥中N素是影响种子发芽的主要因素;添加水葫芦能够促进堆肥的腐熟。     

The composition,leaching, and sorption behavior of some alternative sources of phosphorus for soils

Concerns about the sustainability of inorganic fertilizers necessitate the characterization of alternative P source materials for agronomic P-efficiencies and P losses via leaching. Firstly, this study examined nutrient compositions including P speciation of seven soil amendments: sewage sludge (SS), anaerobic digestate (AD), green compost (GC), food waste compost (FWC), chicken manure (CM), biochar, and seaweed. Secondly, soil P leaching and availability was studied on a subset of four materials (SS, AD, GC, and CM). Sorption of extracts onto columns of a test soil showed strong P retention for SS and compost, but weak P sorption for CM and especially AD, suggesting short-term leaching risks for soil applied AD. Limited P desorption with water or citrate indicated sorbed P was strongly fixed, potentially limiting crop availability. These data indicate that variation in P forms and environmental behavior should be understood to maximize P usage, but minimize leaching and soil P accumulation. Hence, different alternative P source materials need differing recommendations for their agronomic management.     

ESTROM—a Romanian–Swiss research programme

Background, aim, and scope  Composting is an effective treatment process to realize sludge land application. However, nitrogen loss could result in the reduction of nutrient value of the compost products and the stabilization effect of composting on heavy metal concentration and mobility in sludge has been shown to be very limited. Materials and methods  Laboratory-scale experiments were carried out to investigate the effects of bamboo charcoal (BC) on nitrogen conservation and mobility of Cu and Zn during sludge composting. Results  The result indicated that the incorporation of BC into the sludge composting material could significantly reduce nitrogen loss. With 9% BC amendment, total nitrogen loss at the end of composting decreased 64.1% compared with no BC amendment (control treatment). Mobility of Cu and Zn in the sludge may also have been lessened, based on the decline in diethylenetriaminepentaacetic acid-extractable Cu and Zn contents of composted sludge by 44.4% and 19.3%, respectively, compared to metal extractability in the original material. Discussion  Ammonia adsorption capability of BC might be the main reason for the retention of nitrogen in sludge composting materials. Decrease of extractable Cu²⁺ and Zn²⁺ in the composting material mainly resulted from the adsorption of both metals by BC. Conclusions  Incorporation of BC into composting material could significantly lessen the total nitrogen loss during sludge composting. Mobility of heavy metals in the sludge composting material could also be reduced by the addition of BC. Recommendations and perspectives  Bamboo charcoal could be an effective amendment for nitrogen conservation and heavy metal stabilization in sludge composts. Further research into the effect of BC-amended sludge compost material on soil properties, bioavailability of heavy metals, and nutrient turnover in soil needs to be carried out prior to the application of BC-sludge compost in agriculture.     

Co-composting of distillery wastes with animal manures: carbon and nitrogen transformations in the evaluation of compost stability

The aim of this work was to study the viability of recycling the solid wastes generated by the winery and distillery industry by means of co-composting with animal manures, as well as to evaluate the quality of the composts obtained. Two piles, using exhausted grape marc and cattle manure or poultry manure, respectively (at ratios, on a fresh weight basis, of 70:30), were composted by the Rutgers static pile composting system. Throughout the composting process, a number of parameters were monitored, such as pH, electrical conductivity, organic matter, water-soluble carbon, water-soluble polyphenols, different forms of nitrogen (organic nitrogen, ammonium and nitrate) and humification indices (humification ratio, humification index, percentage of humic acid-like C, polymerisation ratio and cation exchange capacity), as well as the germination index. Organic matter losses followed first-order kinetics equation in both piles, the highest organic matter mineralisation rate being observed with exhausted grape marc and cow manure. On the other hand, the mixture with the lowest C/N ratio, using exhausted grape marc and poultry manure, showed the highest initial ammonium contents, probably due to the higher and more labile N content of poultry manure. The increase in the cation exchange capacity revealed the organic matter humification during composting. In contrast, other humification parameters, such as the humification ratio and the humification index, did not show the expected evolution and, thus, could not be used to assess compost maturity. Composting produced a degradation of the phytotoxic compounds, such as polyphenols, to give composts without a phytotoxic character. Therefore, composting can be considered as an efficient treatment to recycle this type of wastes, due to composts presented a stable and humified organic matter and without phytotoxic effects, which makes them suitable for their agronomic use.     

Nitrous oxide flux from landfill leachate-sawdust nitrogenous compost

Composted nitrogenous waste has the potential to produce excessive amounts of nitrous oxide (N2O), a potent greenhouse gas that also contributes to stratospheric ozone depletion. In this laboratory study, sawdust was irrigated with varying amounts of landfill leachate with high NH4+-N content (3950 mg l(-1)). Physicochemical properties, including the amount of N2O produced, were monitored during the composting process over 28 days. A rapid decline in NH4+-N in the first 4 days and increasing NO3--N for 11 days was followed by lower but stabilized levels of available-N, even with repeated leachate irrigation. Less than 0.03% of the leachate-applied N was lost as N2O. Higher leachate applications as much as tripled N2O production, but this represented a lesser proportion overall of the total nitrogen. Addition of glucose to the composting process had no significant effect on N2O production. The derived sawdust-leachate compost supported healthy growth of Sesbania rostrata. It is concluded that compost can be produced from sawdust irrigated with landfill leachate without substantial emission of N2O, although excessive flux of N2O remains about high application rates over longer time periods.     

An Estimation of Construction and Demolition Debris in Seoul,Korea: Waste Amount,Type, and Estimating Model

ABSTRACT

Construction and demolition (C&D) debris is generated at the site of various construction activities. However, the amount of the debris is usually so large that it is necessary to estimate the amount of C&D debris as accurately as possible for effective waste management and control in urban areas. In this paper, an effective estimation method using a statistical model was proposed. The estimation process was composed of five steps: estimation of the life span of buildings; estimation of the floor area of buildings to be constructed and demolished; calculation of individual intensity units of C&D debris; and estimation of the future C&D debris production. This method was also applied in the city of Seoul as an actual case, and the estimated amount of C&D debris in Seoul in 2021 was approximately 24 million tons. Of this total amount, 98% was generated by demolition, and the main components of debris were concrete and brick.     

Integrated Waste Management in a Zone of Northern Italy: Compost Production and Use,and Analytical Control of Compost,Soil, and Crop

Agricultural soils of two Italian maize farms were treated for five years with an industrially produced high-quality compost. Cattle manure and the usual mineral fertilizer were used for comparison purposes. The effects of the organic and mineral fertilizer treatments were studied by analyzing the compost and manure, cultured soils, and harvested material. The grain yield was also determined. Organic fertilization improved soil pH, CEC, content of organic matter and NPK. Soil respiration and N mineralization were found to be higher than in the purely mineral-treated soil. Plant K take-up was improved, whereas grain yield was not affected. It was confirmed that organic fertilization, particularly compost use, maintained and increased soil fertility. The study demonstrated the feasibility of using in loco analytical facilities to follow the entire recycling process—from waste to compost production—and the use of the final product in the field.     

Integrated waste management in a zone of northern Italy: compost production and use, and analytical control of compost, soil, and crop

Agricultural soils of two Italian maize farms were treated for five years with an industrially produced high-quality compost. Cattle manure and the usual mineral fertilizer were used for comparison purposes. The effects of the organic and mineral fertilizer treatments were studied by analyzing the compost and manure, cultured soils, and harvested material. The grain yield was also determined. Organic fertilization improved soil pH, CEC, content of organic matter and NPK. Soil respiration and N mineralization were found to be higher than in the purely mineral-treated soil. Plant K take-up was improved, whereas grain yield was not affected. It was confirmed that organic fertilization, particularly compost use, maintained and increased soil fertility. The study demonstrated the feasibility of using in loco analytical facilities to follow the entire recycling process-from waste to compost production-and the use of the final product in the field.     

Effect of inoculating flower stalks and vegetable waste with ligno-cellulolytic microorganisms on the composting process

A lab-scale composting experiment was carried out using vegetable and flower stalks waste to study the effectiveness of ligno-cellulolytic microorganisms (LCMs) obtained from the previous isolation on composting process, especially on enhancement of biodegradation rate of these organic materials. The addition of LCMs to compost showed promised to be a valuable asset by rendering timely benefits in efficiency, maturity, and quality of the composting. This was evidenced by a significant increase of temperature, O2 consumption and CO2 emission, and population density of LCMs in compost mass compared with that of biotic (addition of culture of horse feces) and abiotic (1% molasses amendment) treatments, as well as control trial. The phytotoxicity assay showed that the substrate became mature after 60 days' composting. The LCMs inoculation enhanced the biodegradation of the composting materials as evidenced by an increasing screening ratio (1.2 cm sieve pore) of 34.5% in the treated trail, compared with that of control, which elucidated that big advantage of adding selected inoculants over other treatment, and screening ratio is a reasonable index to compare the quality of different compost. However, the inoculation seemed to have no significant effect on the moisture content, pH, and the final organic carbon of the composting materials.     

Impact assessment of waste management options in Singapore

This paper describes the application of life cycle assessment for evaluating various waste management options in Singapore, a small-island city state. The impact assessment method by SimaPro is carried out for comparing the potential environmental impacts of waste treatment options including landfilling, incineration, recycling, and composting. The inventory data include gases and leachate from landfills, air emissions and energy recovery from incinerators, energy (and emission) savings from recycling, composting gases, and transport pollution. The impact assessment results for climate change, acidification, and ecotoxicity show that the incineration of materials imposes considerable harm to both human health and the environment, especially for the burning of plastics, paper/cardboard, and ferrous metals. The results also show that, although some amount of energy can be derived from the incineration of wastes, these benefits are outweighed by the air pollution (heavy metals and dioxins/furans) that incinerators produce. For Singapore, landfill gases and leachate generate minimal environmental damage because of the nation's policy to landfill only 10% of the total disposed wastes. Land transportation and separation of waste materials also pose minimal environmental damage. However, sea transportation to the landfill could contribute significantly to acidification because of the emissions of sulfur oxides and nitrogen oxides from barges. The composting of horticultural wastes hardly imposes any environmental damage. Out of all the waste strategies, the recycling of wastes offers the best solution for environmental protection and improved human health for the nation. Significant emission savings can be realized through recycling.     

Effect of Inoculating Flower Stalks and Vegetable Waste with Ligno-cellulolytic Microorganisms on the Composting Process

Abstract

A lab-scale composting experiment was carried out using vegetable and flower stalks waste to study the effectiveness of ligno-cellulolytic microorganisms (LCMs) obtained from the previous isolation on composting process, especially on enhancement of biodegradation rate of these organic materials. The addition of LCMs to compost showed promised to be a valuable asset by rendering timely benefits in efficiency, maturity, and quality of the composting. This was evidenced by a significant increase of temperature, O₂ consumption and CO₂ emission, and population density of LCMs in compost mass compared with that of biotic (addition of culture of horse feces) and abiotic (1% molasses amendment) treatments, as well as control trial. The phytotoxicity assay showed that the substrate became mature after 60 days’ composting. The LCMs inoculation enhanced the biodegradation of the composting materials as evidenced by an increasing screening ratio (1.2 cm sieve pore) of 34.5% in the treated trail, compared with that of control, which elucidated that big advantage of adding selected inoculants over other treatment, and screening ratio is a reasonable index to compare the quality of different compost. However, the inoculation seemed to have no significant effect on the moisture content, pH, and the final organic carbon of the composting materials.