Effects of Low Temperature-tolerant Microbial Inoculants from Municipal Solid Waste Compost on Turf Storage in Winter

Beneficial microorganisms were extracted from municipal solid waste compost and treated under low temperature stress to prepare complex microbial inoc- ulants. Turfgrass was inoculated with the prepared microbial inoculants to investigate the ecological effect of ~crobial inoculants on turf storage in winter. The re- suits showed that complex low temperature tolerant microbial inoculants significandy improved plant height and aboveground biomass of turfgrass. Compared with the non-inoculated control, plant height and biomass of the first batch of inoculated turfgrass were enhanced by 6.47% and 14.32%, respectively; and they were en- hanced by 6.94% and 17.41%, respectively, for the second batch of inoculated turfgrass. Under low temperature stress in winter, the reviving rate of inoculated tarfgrass was significandy higher than that of control, which was improved by 3.34% and 43.33% for the first and second batches of inoculated turfgrass respective- ly. After low temperature storage in winter, inoculated turfgrass revived in advance; specifically, the reviving date of the second batch of inoculated turfgrass was 3 d earlier than that of control. This low temperature tolerant microbial consortium was effective for turfgrass as an ecofriendly and acceptable technology to improve plant performance and development in winter and accelerate time to market of turf.

Synergistic effects of chemical additives and mature compost on reducing H_2S emission during kitchen waste composting

Additives could improve composting performance and reduce gaseous emission,but few studies have explored the synergistic of additives on H_(2)S emission and compost maturity.This research aims to make an investigation about the effects of chemical additives and mature compost on H_(2)S emission and compost maturity of kitchen waste composting.The results showed that additives increased the germination index value and H_(2)S emission reduction over 15 days and the treatment with both chemical additives and mature compost achieved highest germination index value and H_(2)S emission reduction(85%).Except for the treatment with only chemical additives,the total sulfur content increased during the kitchen waste composting.The proportion of effective sulfur was higher with the addition of chemical additives,compared with other groups.The relative abundance of H_(2)S-formation bacterial(Desulfovibrio)was reduced and the relative abundance of bacterial(Pseudomonas and Paracoccus),which could convert sulfur-containing substances and H_(2)S to sulfate was improved with additives.In the composting process with both chemical additives and mature compost,the relative abundance of Desulfovibrio was lowest,while the relative abundance of Pseudomonas and Paracoccus was highest.Taken together,the chemical additives and mature compost achieved H_(2)S emission reduction by regulating the dynamics of microbial community.

A pilot field-scale study on biotrickling filter treatment of NH_3-containing odorous gases from organic waste composting plants

The use of a biotrickling filter was investigated for a pilot field-scale elimination of NH3 gas and other odorous gases from a composting plant in Tongzhou District, Beijing. The inlet gas flow rate was 3500 m3/h and NH3 concentration fluctuated between 2.76–27.84 mg/m3, while the average outlet concentration was 1.06 mg/m3 with an average of 94.9% removal. Critical volumetric loading (removal efficiency=100%) was 11.22 g-N/(m3·h). The odor concentration removal was 86.7%. NH3 removal efficiency decreased as the free ammonia (FA) in the trickling liquid increased. The pressure drop was maintained at about 50 Pa/m and was never more than 55 Pa/m. During the experiment, there was neither backflushing required nor any indication of clogging. Overall, the biotrickling filter was highly efficient and cost-effective for the simultaneous biodegradation of NH3 and other odorous gases from composting, suggesting the possibility of treating odorous gases at the industrial level.

Use of additive and pretreatment to control odors in municipal kitchen waste during aerobic composting

The effects of adding a bulking agent and chemically pretreating municipal kitchen waste before aerobic composting were studied using a laboratory-scale system. The system used20-L reactors and each test lasted 28 days. The objective was to decrease NH3 and H2S emissions during composting. The bulking agent, dry cornstalks, was mixed with the kitchen waste to give a mixture containing 15%（wet weight） bulking agent. A combined treatment was also conducted, in which kitchen waste mixed with the bulking agent was pretreated with ferric chloride（FeC l3）. Less leachate was produced by the composted kitchen waste mixed with bulking agent than by the kitchen waste alone, when the materials had reached the required maturity. The presence of cornstalks also caused less H2 S to be emitted, but had little impact on the amount of NH3 emitted. The FeC l3 was found to act as an effective chemical flocculant,and its presence significantly decreased the amounts of NH3 and H2S emitted. Kitchen waste mixed with cornstalks and treated with FeC l3 emitted 42% less NH3 and 76% less H2 S during composting than did pure kitchen waste.

Comparative effects of composted organic waste and inorganic fertilizer on nitrate leachate from the farm soils of northern Guam

The purpose of this study was to quantify the release of nitrate into vadose zone as well as the nitrogen-holding capacity of compost applied on calcareous soils of northern Guam amended with both inorganic fertilizer and composted organic waste,to examine potentially adverse effect of these nutrient materials to groundwater quality.Three different nitrogen levels each of the composted organic waste and the inorganic fertilizer were applied to corn(maize)(farmland)study plots for three consecutive seasons,two dry and one rainy season.During each season,soil organic matter(SOM,w/w%)content and carbon-nitrogen ratio(C/N,w/w%),were determined for analysis of the nitrogen-holding capacity of these calcareous soils.Nitrate levels in soil pore water were also determined for study of potential groundwater contamination.For three seasons,compost plots showed higher SOM%contents and lower C/N%than fertilizer plots.That is,compost-treated soils showed higher SOM content and adsorbed more nitrogen under normalized soil mass than did fertilizer-treated soils.Nitrate levels in pore water were generally higher on compost plots during early stages of corn but were generally higher on fertilizer plots during active leaf,tasseling,and maturity stages.During the rainy season,nitrate leachate seemed to increase,but this trend could not be confirmed because rainfall amounts were not measured.Overall,composted organic waste proved to be a good amendment for soil productivity and agricultural sustainability while reducing nitrate leachate from northern Guam farmland.

A new complex plant for carbonization and composting of municipal wastes

A new complex plant for carbonization and composting of municipal wastes proposed for Gero City is introduced. The separated combustible waste and non-separated combustible waste are carbonized in two fluidized carbonization furnaces in the plant, and the coke produced is used in steelworks. The separated garbage and forest-wastes are mixed with dried septic-tank sludge to produce high quality compost for farms. This use of waste materials in the complex plant considerably lowers the amount of waste going to land-fills, and in addition, creates lower total emission of dioxins and carbon dioxide into the environment.

Humification characterization of biochar and its potential as a composting amendment

Biochar has received increasing attention due to its applications as a soil amendment. Here, the chemical properties of solid and water-extractable fractions of four biochar samples were investigated. The results showed that wood biochar and bamboo biochar samples were 60%-80% more hydrophobic than those of rice husk biochar and rice husk ash. In addition, the acidity was 3.88 mmol/g from the total functional groups and 1.03 mmol/g from the carboxyl groups/lactones/phenols found in the wood biochar sample, which were about 1.5 times greater than those of the bamboo biochar sample. These functional groups could be used to determine the sorptive capacity of biochar for ionic solutes and water content and to increase the degradation of compost organics. The wood biochar sample was found to have the most humification materials （fulvic acid-like material ＋ humic acid-like material） in the water-extractable fraction, which was 3-10 times higher than that in the rice husk biochar and rice husk ash; humified materials were not detected in the bamboo biochar sample. Humification materials in biochar may be involved in increasing the proportion of humic acid-like materials in humic-like substances within the compost product. Wood biochar had better hydrophobic, sorptive, aromatic, and humification properties compared to other biochars, suggesting that it may be used in composting in order to exert its effect as both a bulking agent and a composting amendment during the solid waste composting process.

Efects of solution chemistry on arsenic(V) removal by low-cost adsorbents

Natural and anthropogenic arsenic （As） contamination of water sources pose serious health concerns, especially for small communities in rural areas. This study assessed the applicability of three industrial byproducts （coal fly ash, lignite, and green waste compost） as the low-cost adsorbents for As（V） removal under various field-relevant conditions （dissolved oxygen, As（V）/Fe ratio, solution pH, and presence of competing species）. The physico-chemical properties of the adsorbents were characterized by XRD, XRF, FT-IR, and NMR analysis. Batch experiments demonstrated that coal fly ash could provide effective As（V） removal （82.1%-95%） because it contained high content of amorphous iron/aluminium hydroxides for As（V） adsorption and dissolvable calcium minerals for calcium arsenate precipitation. However, the addition of lignite and green waste compost was found unfavourable since they hindered the As（V） removal by 10%-42% possibly due to dissolution of organic matter and ternary arsenate-iron-organic matter complexes. On the other hand, higher concentrations of dissolved iron （comparing As（V）/Fe ratios of 1：1 and 1：10） and dissolved oxygen （comparing 0.2 and 6 mg/L） only marginally enhanced the As（V） removal at pH 6 and 8. Thus, addition of dissolved iron, water aeration, or pH adjustment became unnecessary because coal fly ash was able to provide effective As（V） removal under the natural range of geochemical conditions. Moreover, the presence of low levels of background competing （0.8 or 8 mg/L of humic acid, phosphate, and silicate） imposed little influence on As（V） removal, possibly because the high adsorption capacity of coal fly ash was far from exhaustion. These results suggested that coal fly ash was a potentially promising adsorbent that warranted further investigation.