Composting is an effective methodology for the treatment of organic waste like pig manure (PM) beforeland application. However, nitrogen loss through NH3 volatilization during the thermophilic phase is oneof the major disadvantages of composting. The presence of Cu and Zn in compost arising from pig feedadditives is also an issue. In this study the effects of bamboo charcoal (BC) and bamboo vinegar (BV)added to composting piles on nitrogen conservation and immobility of Cu and Zn during PM compostingwas investigated. Total Kjeldahl nitrogen (TKN) loss and mobility of Cu and Zn decreased with increasedBC addition. TKN loss and mobility of Cu and Zn in the treatment with 9% BC at the end of compostingsignificantly decreased by 65%, 35% and 39% respectively, as compared to the control. Addition of BV furtherdecreased TKN loss. After composting, TKN loss in the treatment with 3% BC + 0.4% BV was 23% lowerthan that in the treatment with 9% BC. The final results indicated that by adding BC or BC + BV into PMcomposting is an effective method to reduce TKN loss and control the mobility of Cu and Zn.

Ex situ nitrification followed by denitrification inside the landfill has been recommended to removeammonia from leachate. The effects of increasing nitrate load and decreasing organic carbon content inthe injected leachate on the denitrifying capacity of municipal solid waste (MSW) were investigated.Results showed that MSWpossesses a high denitrification capacity. Nitrate reduction could be initiatedwithin 48 h after the first addition of nitrate. Nitrate reduction rate increased with the increasing nitrateloading concentration. When the nitrate loading concentration was increased to 850 mg L_1, nitratereduction rate reached up to 35 mg L_1 h_1. Nitrite accumulation could be found after the addition ofnitrate in each test. However, the maximum nitrite accumulation efficiency declined with increasednitrate load. Organic carbon played an important role in the reduction of nitrate, and both endogenousand exogenous organic materials could act as electron donors.

Photosynthetic assimilation of CO2 is a primary source of carbon in soil and root-exudates and can influence the community dynamics of rhizosphere organisms.-Thus, if carbon partitioning is affected in transgenic crops, rhizosphere microbial-communities may also be affected. In this study, the temporal effects of gene-transformation on carbon partitioning in rice and rhizosphere microbial communities-were investigated under greenhouse conditions using the 13C pulse-chase-labeling method and phospholipid fatty acid (PLFA) analysis. The 13C contents in-leaves of transgenic (Bt) and nontransgenic (Ck) rice were significantly different at-the seedling, booting and heading stages. There were no detectable differences in-13C distribution in rice roots and rhizosphere microorganisms at any point during-rice development. Although a significantly lower amount of Gram-positive-bacterial PLFAs and a higher amount of Gram-negative bacterial PLFAs were-observed in Bt rice rhizosphere as compared with Ck at all plant development-stages, there were no significant differences in the amount of individual 13C-PLFA-between Bt and Ck rhizospheres at any growing stage. These findings indicate that-the insertion of cry1Ab and marker genes into rice had no persistent or adverse-effect on the photosynthate distribution in rice or the microbial community-composition in its rhizosphere-

Background, aim, and scope Composting is an effectivetreatment process to realize sludge land application.However, nitrogen loss could result in the reduction ofnutrient value of the compost products and the stabilizationeffect of composting on heavy metal concentration andmobility in sludge has been shown to be very limited.Materials and methods Laboratory-scale experiments werecarried out to investigate the effects of bamboo charcoal(BC) on nitrogen conservation and mobility of Cu and Znduring sludge composting.Results The result indicated that the incorporation of BCinto the sludge composting material could significantlyreduce nitrogen loss. With 9% BC amendment, totalnitrogen 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 beenlessened, based on the decline in diethylenetriaminepentaaceticacid-extractable Cu and Zn contents of compostedsludge by 44.4% and 19.3%, respectively, compared tometal extractability in the original material.Discussion Ammonia adsorption capability of BC might bethe main reason for the retention of nitrogen in sludgecomposting materials. Decrease of extractable Cu2+ andZn2+ in the composting material mainly resulted from theadsorption of both metals by BC.Conclusions Incorporation of BC into composting materialcould significantly lessen the total nitrogen loss during sludgecomposting. Mobility of heavy metals in the sludge compostingmaterial could also be reduced by the addition of BC.Recommendations and perspectives Bamboo charcoalcould be an effective amendment for nitrogen conservationand heavy metal stabilization in sludge composts. Furtherresearch into the effect of BC-amended sludge compostmaterial on soil properties, bioavailability of heavy metals,and nutrient turnover in soil needs to be carried out prior tothe application of BC-sludge compost in agriculture.

Oxygen availability in landfill cover soil is a major limitation to the growth and activity of methanotrophsas methane oxidation is an aerobic microbial process. Plants tolerant to high concentrations of landfillgas (LFG) may play an important role in improving methane oxidation within landfill cover soil andreducing emission of methane, a greenhouse gas, from it. In this study, the effect of an LFG tolerant plantChenopodium album L. on methane oxidation activity (MOA) and bacterial community composition inlandfill cover soil was investigated. Soil samples from four simulated lysimeters with and without LFGand plant vegetation were taken at 4 stages during the plant’s development cycle. Results showed thatthe total number of culturable bacteria in soil could be significantly increased (P < 0.05) by the growth ofC. album. The total number of methanotrophs and MOA in soils with LFG was significantly higher(P < 0.05) than in soils without LFG on sampling days 90, 150 and 210. The total number of methanotrophsand MOA in lysimeters with LFG added increased in the presence of C. album when the plantentered the seed setting stage. Polymerase chain reaction and denaturing gradient gel electrophoresis(PCR-DGGE) gel patterns of 16S rDNA gene fragment and band sequencing analyses showed apparentdifferences in soil bacterial communities in the presence of LFG and plant vegetation. Members of thegenus Methylosarcina were found to be the active and dominant methanotrophs in rhizosphere soil of C.album with LFG, while Methylococcus, Methylocystis, and Methylosinus were the primary methanotrophgenera in LFG soil without C. album. Thus, C. album appears to select for specific methanotrophic bacteriain the presence of LFG. Soil MOA and microbial diversity can also be significantly affected by the presenceof this plant.

Use of transgenic crops, including those expressing the insecticidal Cry protein from Bt, is increasing at a rapid rate in worldwide.Field and laboratory studies of transgenic Bt crops have been carried out to detect the persistence and activity of the Cry protein in soiland its effect on soil microorganisms to assess their risks to environment. However, there were few studies that evaluate the seasonaleffects of Bt rice on rhizosphere soil microbial communities compared to those of insecticides commonly applied in paddy soil for thecontrol of lepidopteran insects. In this study, seasonal effects of transgenic rice expressing the Cry1Ab insecticidal protein active againstlepidoperan pests and the insecticide triazophos [3-(o,o-diethyl)-1-phenyl thiophosphoryl-1,2,4-triazol] on soil enzyme activities andmicrobial communities were compared under field conditions. During a 2-year field study, rhizosphere soil samples of transgenic-Bt rice(Bt), non-Bt parental rice (Ck) and non-Bt parental rice with triazophos (Ckp) applied were taken at four stages in the rice developmentalcycle: seedling, booting, heading and maturing. Microbial processes were investigated by measuring different biochemical activitiesincluding those involved in C and P cycling. Denaturing gradient gel electrophoresis (DGGE) and terminal-restriction fragment lengthpolymorphism (T-RFLP) analyses were used to compare rhizosphere microbial compositions. Some occasional and inconsistent effectsof the application of triazophos on the bacterial composition in the rhizosphere soil of rice plant were found at the booting and headingstages as compared with that of transgenic-Bt rice. There were no statistically significant differences (P40.05) in phosphatase activity,dehydrogenase activity, respiration, methanogenesis or fungal community composition in rhizosphere soil between Bt, Ck and Ckp overthe rice cropping cycle. However, seasonal variations in the selected enzyme activities and microbial community composition in therhizosphere soil of Bt, Ck and Ckp were clearly detected. These results suggested that the changes in rhizophere soil microbial communitycomposition associated with the crop growth stage overweighed the application of triazophos and the cry1Ab gene transformation.KMD1 (Bt) rice expressing the cry1Ab gene had no measurable adverse effect on the key microbial processes or microbial communitycomposition in rhizophere soil over 2 years of rice cropping.

Municipal solid waste (MSW) decomposition under oversaturated condition in comparison with leachate recirculation was investigated in twosimulated reactors (A and B). Reactor B was operated with leachate recirculation while in reactor A, an oversaturated condition was maintainedwithout leachate recirculation. Results showed that MSW decomposition in reactor A was much faster than that in reactor B. The final CODcrconcentration and pH value of leachates in reactor Awere around 1000 mg L_1 and 7.0, respectively, in comparison to 18,000 mg L_1 and below6.5 in reactor B after 420 days of incubation. Biogas production was positively related to ambient temperature. The total biogas and methane yieldswere 2800 L and 1330 L in reactor A while only 1470 L and 600 L in reactor B. These results indicated that the relative retardation of MSWdegradation in reactor B was primarily resulted from the increased resistance of mass transfer and the accumulation of biogas caused by leachaterecirculation and the resultant acid inhibition. Bioreactor landfill operated under liquid oversaturated and MSW loose condition could be apromising approach for accelerating municipal solid waste degradation.

Municipal solid waste (MSW) source-classified collection represents a change in MSW management in China and other developing countries.Comparative experiments were performed to evaluate the effect of a newly established MSW source-classified collection system on the emissionof PCDDs/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) and heavy metals (HMs) from a full-scale incinerator in China. As a result ofpresorting and dewatering, the chlorine level, heavy metal and water content were lower, but heat value was higher in the source-classified MSW(classified MSW) as compared with the conventionally mixed collected MSW (mixed MSW). The generation of PCDDs/Fs in flue gas from theclassified MSW incineration was 9.28 ng I-TEQ/Nm3, only 69.4% of that from the mixed MSW incineration, and the final emission of PCDDs/Fswas only 0.12 ng I-TEQ/Nm3, although activated carbon injection was reduced by 20%. The level of PCDDs/Fs in fly ash from the bag filterwas 0.27 ng I-TEQ/g. These results indicated that the source-classified collection with pretreatment could improve the characteristics of MSW forincineration, and significantly decrease formation of PCDDs/Fs in MSW incineration. Furthermore, distributions of HMs such as Cd, Pb, Cu, Zn,Cr, As, Ni, Hg in bottom ash and fly ash were investigated to assess the need for treatment of residual ash.

Two three-stage biofilters packed with compost (BFC) or sludge (BFS), respectively, were prepared for removing trimethylamine (TMA) fromwaste gases. The correlation between reactor performance and bacterial community composition was investigated. Although TMA could besuccessfully removed by both biofilters, TMA removal efficiency in the bottom stage of the BFC was considerably higher than that of the BFS.Moreover, NH3 generated by the degradation of TMA could be removed in the BFC, while it accumulated in the BFS. Spatial and temporal shiftsof bacterial community composition in both biofilters developed differently as assessed by polymerase chain reaction-denaturing gradient gelelectrophoresis (PCR-DGGE) followed by clone library analysis. Results showed that the lack of ammonia-oxidizing bacteria (AOB) may havecontributed to the accumulation of NH3 in the BFS. Therefore, AOB may play a decisive role in a complete degradation of TMA. It is necessaryfor the sludge packing material to be inoculated with AOB in order to initiate ammonia oxidation in the bioreactor. Understanding of microbialcommunity compositions in biofilters plays an important role in seeking biological limiting factors related to the removal efficiencies of TMA andother compounds from waste gas and further enhancing the performance of biofilters.

There have been few investigations of the possible effects of genetically engineered plants on the microbiota and enzyme activities in flooded soil. We studied the influence of the transgenic rice KeMingDao (KMD) straw on the culturable microbiota and enzymatic activities in a flooded paddy soil under laboratory conditions. KMD contained a synthetic cry1Ab gene from Bacillus thuringiensis under the control of a maize ubiquitin promoter and linked in tandem with the gusA and hpt genes. The results showed that there were only some occasional significant differences eP, 0:05T in the number of Colony forming units of aerobic bacteria, actinomycetes and fungi and in the number of anaerobic fermentative bacteria, denitrifying bacteria, hydrogen-producing acetogenic bacteria, and methanogenic bacteria between the paddy soil amended with Bt-transgenic rice straw and with the non-Bt parental rice straw during the early stages of incubation. From d14 to d84 there were significant increases eP, 0:05T in soil dehydrogenase and soil neutral phosphatase activity in soils amended with rice straw compared to soil without added straw. The dehydrogenase activity was significantly greatly (almost 1.95-fold) in soil amended with Bttransgenic straw from d7 to d14 but from d21 to d49 there was significantly greater activity (about 1.47-fold) in the soil amended with non- Bt-straw. There were no apparent differences between the activity of soil neutral phosphatase in the soils to which non-Bt-straw and Bt-straw had been added. However, both soils to which rice straws were added demonstrated significant differences in the number of microorganisms except for aerobic bacteria and enzymatic activities with respect to the control soil throughout the incubation. The above results indicated that the Bt-straw from KMD transgenic rice is not toxic to a variety of culturable microorganisms in the studied flooded paddy soil.