Economic growth and environmental sustainability from renewable energy applications

The use of fossil fuel causes severe environmental problem such as climate change in the global scale and acid rain in the regional level. Along with its nonrenewable property, renewable and clean energy sources must be explored so as to keep the economy growing sustainably. Nowadays many renewable energy alternatives such as bioenergy, solar power, hydro power, and wind power have been employed, and each of them has their own pros and cons. This special issue focuses on the use of urban and rural wastes in several aspects such as (i) the use agricultural residuals in bioenergy production; (ii) treatments of municipal solid waste in pyrolysis and biochar application; (iii) sewer sludge and other organic matters in renewable energy production; and (iv) plastic materials in wind farm construction and production of solar panels, to assist the production of renewable energy to improve the resource management and maintain the environment.

The Feasibility Research on Producing Lightweight Aggregates Made from the Waste Stone Sludge

This paper aims to investigate on producing lightweight aggregates made from the waste stone sludge. It was utilizing the mechanism of high temperature solid solution method as well as in coordination with the production method of reservoir sediments lightweight aggregates to conduct an investigation on the development of lightweight aggregate using stone sludge. The investigation shows that the analysis results for the stone sludge are not in the limits of the expandable region of the ternary diagram due to the high content of FeOx. That caused the expandable temperature range was narrow, the expandability of aggregate was poor and the aggregate particle density was relatively high. But, it still could be producing lightweight aggregates made from the waste stone sludge in this paper. The better solution may be to add the high-content organic materials to adjust chemical composition, such as water purification sludge, sewer sludge, reservoir sludge etc.

Draft Genome Sequence of the Methane-Oxidizing Bacterium Methylococcus capsulatus (Texas)

ABSTRACTMethanotrophic bacteria perform major roles in global carbon cycles via their unique enzymatic activities that enable the oxidation of one-carbon compounds, most notably methane. Here we describe the annotated draft genome sequence of the aerobic methanotrophMethylococcus capsulatus(Texas), a type strain originally isolated from sewer sludge.

Comparison of methane production by co-digesting fruit and vegetable waste with first stage and second stage anaerobic digester sludge from a two stage digester

Fruit and vegetable waste (FVW) was co-digested with first stage (FSS) and second stage anaerobic digester sludge (SSS) separately, over the course of 10 days, in batch reactors. Addition of FVW significantly increased the methane production in both sludges. After 10 days of digestion FSS + FVW produced 514 ± 57 L CH4 kg VS−1added compared with 392 ± 16 L CH4 for the SSS + FVW. The increased methane yield was most likely due to the higher inoculum substrate ratio of the FSS. The final VS and COD contents of the sewer sludge and FVW mixtures were not significantly different from the control values suggesting that all of the FVW added was degraded within 10 days. It is recommended that FVW be added to the first stage of the anaerobic digester in order to maximize methane generation.

Increased biogas production in a wastewater treatment plant by anaerobic co-digestion of fruit and vegetable waste and sewer sludge – A full scale study

Anaerobic digestion is a well established technology for the reduction of organic matter and stabilization of wastewater. Biogas, a mixture of methane and carbon dioxide, is produced as a useful by-product of the process. Current solid waste management at the city of Prince George is focused on disposal of waste and not on energy recovery. Co-digestion of fresh fruit and vegetable waste with sewer sludge can improve biogas yield by increasing the load of biodegradable material. A six week full-scale project co-digesting almost 15,000 kg of supermarket waste was completed. Average daily biogas production was found to be significantly higher than in previous years. Digester operation remained stable over the course of the study as indicated by the consistently low volatile acids-to-alkalinity ratio. Undigested organic material was visible in centrifuged sludge suggesting that the waste should have been added to the primary digester to prevent short circuiting and to increase the hydraulic retention time of the freshly added waste.