Mitigation of global greenhouse gas emissions from waste: conclusions and strategies from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. Working Group III (Mitigation).

Greenhouse gas (GHG) emissions from post-consumer waste and wastewater are a small contributor (about 3%) to total global anthropogenic GHG emissions. Emissions for 2004-2005 totalled 1.4 Gt CO2-eq year(-1) relative to total emissions from all sectors of 49 Gt CO2-eq year(-1) [including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and F-gases normalized according to their 100-year global warming potentials (GWP)]. The CH4 from landfills and wastewater collectively accounted for about 90% of waste sector emissions, or about 18% of global anthropogenic methane emissions (which were about 14% of the global total in 2004). Wastewater N2O and CO2 from the incineration of waste containing fossil carbon (plastics; synthetic textiles) are minor sources. Due to the wide range of mature technologies that can mitigate GHG emissions from waste and provide public health, environmental protection, and sustainable development co-benefits, existing waste management practices can provide effective mitigation of GHG emissions from this sector. Current mitigation technologies include landfill gas recovery, improved landfill practices, and engineered wastewater management. In addition, significant GHG generation is avoided through controlled composting, state-of-the-art incineration, and expanded sanitation coverage. Reduced waste generation and the exploitation of energy from waste (landfill gas, incineration, anaerobic digester biogas) produce an indirect reduction of GHG emissions through the conservation of raw materials, improved energy and resource efficiency, and fossil fuel avoidance. Flexible strategies and financial incentives can expand waste management options to achieve GHG mitigation goals; local technology decisions are influenced by a variety of factors such as waste quantity and characteristics, cost and financing issues, infrastructure requirements including available land area, collection and transport considerations, and regulatory constraints. Existing studies on mitigation potentials and costs for the waste sector tend to focus on landfill CH4 as the baseline. The commercial recovery of landfill CH4 as a source of renewable energy has been practised at full scale since 1975 and currently exceeds 105 Mt CO2-eq year(-1). Although landfill CH4 emissions from developed countries have been largely stabilized, emissions from developing countries are increasing as more controlled (anaerobic) landfilling practices are implemented; these emissions could be reduced by accelerating the introduction of engineered gas recovery, increasing rates of waste minimization and recycling, and implementing alternative waste management strategies provided they are affordable, effective, and sustainable. Aided by Kyoto mechanisms such as the Clean Development Mechanism (CDM) and Joint Implementation (JI), the total global economic mitigation potential for reducing waste sector emissions in 2030 is estimated to be > 1000 Mt CO2-eq (or 70% of estimated emissions) at costs below 100 US$ t(-1) CO2-eq year(-1). An estimated 20-30% of projected emissions for 2030 can be reduced at negative cost and 30-50% at costs < 20 US$ t(-) CO2-eq year(-1). As landfills produce CH4 for several decades, incineration and composting are complementary mitigation measures to landfill gas recovery in the short- to medium-term--at the present time, there are > 130 Mt waste year(-1) incinerated at more than 600 plants. Current uncertainties with respect to emissions and mitigation potentials could be reduced by more consistent national definitions, coordinated international data collection, standardized data analysis, field validation of models, and consistent application of life-cycle assessment tools inclusive of fossil fuel offsets.     

Removal of hydrocarbons from Nile water

The need to remove hydrocarbons from water supply sources raises questions on the efficiency of the present water treatment processes in removing hydrocarbons. Therefore, the effectiveness of physicochemical processes involving chlorination, chemical coagulation and sand filtration were investigated. The effect of variable filtration media was also examined. In addition, the use of an activated carbon column was considered, and the effect of different retention times was evaluated. Results of this study showed that chemical coagulation using alum and Nalco removed only 32% of the total hydrocarbons and 80% of turbidity. Use of sand and a mixture of anthracite and sand filters showed additional removal of hydrocarbons and turbidity during the continuous filtration process. Increasing the anthracite depth relative to the total effective filtration depth increases the efficiency of the filter. Adsorption on granular activated carbon was shown to be an effective means for the removal of hydrocarbons. Results obtained indicated that the carbon adsorption capacity increases linearly as the retention time increases.     

Evaluation of the mutagenic potential of some compounds using Salmonella typhimurium

The mutagenicity of sodium nitrite, potassium chromate, O-tolidine, and smoke condensate from tobacco was shown on Salmonella typhimurium TA 1535. Sodium nitrite was definitely mutagenic on TA 1535 without S-9 mix. Potassium chromate without S-9 mix was also mutagenic on TA 1535. However, addition of S-9 mix resulted in a complete loss of potassium chromate mutagenicity. O-tolidine with and without S-9 mix elicited a very weak and variable mutagenic effect for strain TA 1535. Smoke condensate from pipe tobacco without S-9 mix elicited a weak mutagenic effect, whereas with S-9 mix it showed no mutagenicity on TA 1535.     

Microbial degradation of hydrocarbons in Ismailia canal water

The biodegradation of hydrocarbons was performed in refinery wastewater obtained by natural microbial flora in Ismailia canal water. About 87% of hydrocarbons were degraded after 9 days under simulated natural conditions. It was found that the addition of fuel oil to the canal water, which already contained significant amounts of refinery wastewater, retarded biological degradation. Percentage of degradation was found to be 67%. This increase in the hydrocarbons concentration affects dramatically on the generation rate of microorganisms present naturally in canal water.     

Resource estimation using random recursive equation models

Major policy decisions concerning resource use are made on the availability of resource information in a given period of time. In this paper, resource use strategies are discussed using random recursive equation techniques. The model incorporates the random disturbances occuring during short intervals of time. The discrete-time model is designed to predict the expected resource availability and to indicate the precision in terms of its variance.     

Biosynthesis and Characterization of Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) from Bacillus cereus S10

The biodegradable and biocompatible copolymer poly-(3-hydroxybutyrate-co-5 mol% 3-hydroxyvalerate), poly-(3HB-co-5 mol% 3HV), was synthesized by Bacillus cereus S10 and the highest yield was determined as 69.91 % at pH 7 and 30 °C after 48 h of incubation using a glucose as the sole carbon source. Poly-(3HB-co-5 mol% 3HV) was purified from bacterial biomass using chloroform. FTIR analysis showed absorption bands at 1,723, 1,274, 1,373, 1,453, 2,932 cm^?1 corresponding to C=O, C–O stretching, CH₃, –CH₂ and –CH groups, respectively. ¹H-NMR and ¹³C-NMR analysis confirmed that the copolymer was composed of 95 mol% of 3-hydroxybutrate and 5 mol% of 3-HV monomeric units. Poly-(3-HB-co-5 mol% 3HV) was used for nanoparticles preparation. The diameter of nanoparticles was 202 nm.