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.