Potential contribution of the wastewater sector to energy supply

2011 ◽  
Vol 63 (8) ◽  
pp. 1765-1771 ◽  
Author(s):  
S. Heubeck ◽  
R. M. de Vos ◽  
R. Craggs

The biological treatment of wastewater could yield high energy fuels such as methane and alcohols, however most conventional treatment systems do not recover this energy potential. With a simple model of the energy yields of various wastewater treatment technologies it is possible to demonstrate how minor shifts in technology selection can lead the industry from being identified as predominantly energy intensive, to being recognised as a source of energy resources. The future potential energy yield is estimated by applying energy yield factors to alternative use scenarios of the same wastewater loads. The method for identifying the energy potential of wastewater was demonstrated for the New Zealand wastewater sector, but can equally be applied to other countries or regions. The model suggests that by using technologies that maximise the recovery of energy from wastewater, the potential energy yield from this sector would be substantially increased (six fold for New Zealand).

2021 ◽  
Vol 17 (3) ◽  
pp. 240-247
Author(s):  
O. M. Hanzhenko

Purpose. To reveal the influence of harvest timing of biomass of sweet sorghum various varieties and hybrids on their productivity and biofuel yield in the zone of insufficient moisture in the Eastern Forest-Steppe of Ukraine. Methods. Biological (conducting field research during 2017–2020) and statistical (descriptive statistics, analysis of variance, correlation and regression analyzes). Results. The lowest yield of sweet sorghum green biomass was during harvesting in early August. In ‘Sylosne 42’ and ‘Favoryt’ varie­ties it was 52.6 and 61.1 t/ha, in ‘Medovyi F1’ and ‘Dovista’ hybrids – 76.3 and 77.7 t/ha, respectively. The postponement of harvesting to mid-September allows increasing the yield of varieties ‘Favoryt’ and ‘Sylosne 42’ to 97.1 and 103.5 t/ha, ‘Dovista’ and ‘Medovyi F1’ hybrids up to 146.6 and 132.9 t/ha, respectively. With even later harvesting periods, an increase in the yield of green biomass was observed only in ‘Dovista’ (up to 152.5 t/ha). In the full ripening phase (BBCH 92–98), sugar sorghum plants accumulate the maximum amount of sugars in the sap. The highest cap sugar content was in plants of ‘Medovyi F1’ hybrid – 17.5%, in the other studied cultivars it varied from 14.8 to 15.5%. The hi­g­hest yield of biofuel and energy per unit area was achieved with gro­wing ‘Dovista’ (up to 815.8 GJ/ha) and ‘Medovyi F1’ (up to 792.0 GJ/ha) hybrids. Despite the high level of plasti­city, ‘Favoryt’ variety is inferior in total energy yield (up to 547.2 GJ/ha). ‘Sylosne 42’ has the lowest plasticity index (b = 0.79); however, it is the most stable variety, which allows to obtain a stable, though not high, energy yield (up to 559.6 GJ/ha). Conclusions. In the zone of insufficient moisture in the Eastern Forest-Steppe of Ukraine, the hi­ghest productivity indicators and the maximum energy potential can be provided by the hybrids of sweet sorghum ‘Dovista’ and ‘Medovyi F1’ for their harvesting not earlier than the phase of full maturity


2020 ◽  
Vol 80 (2) ◽  
pp. 133-146
Author(s):  
L Zhang ◽  
Z Zhang ◽  
J Cao ◽  
Y Luo ◽  
Z Li

Grain maize production exceeds the demand for grain maize in China. Methods for harvesting good-quality silage maize urgently need a theoretical basis and reference data in order to ensure its benefits to farmers. However, research on silage maize is limited, and very few studies have focused on its energetic value and quality. Here, we calibrated the CERES-Maize model for 24 cultivars with 93 field experiments and then performed a long-term (1980-2017) simulation to optimize genotype-environment-management (G-E-M) interactions in the 4 main agroecological zones across China. We found that CERES-Maize could reproduce the growth and development of maize well under various management and weather conditions with a phenology bias of <5 d and biomass relative root mean square error values of <5%. The simulated results showed that sowing long-growth-cycle cultivars approximately 10 d in advance could yield good-quality silage. The optimal sowing dates (from late May to July) and harvest dates (from early October to mid-November) gradually became later from north to south. A high-energy yield was expected when sowing at an early date and/or with late-maturing cultivars. We found that Northeast China and the North China Plain were potential silage maize growing areas, although these areas experienced a medium or even high frost risk. Southwestern maize experienced a low risk level, but the low soil fertility limited the attainable yield. The results of this paper provide information for designing an optimal G×E×M strategy to ensure silage maize production in the Chinese Maize Belt.


1994 ◽  
Vol 30 (5) ◽  
pp. 87-95 ◽  
Author(s):  
Susan E. Murcott ◽  
Donald R. F. Harleman

In the past decade, the development of polymers and new chemical technologies has opened the way to using low doses of chemicals in wastewater treatment. “Chemical upgrading” (CU) is defined in this paper as an application of these chemical technologies to upgrade overloaded treatment systems (typically consisting of conventional primary plus biological treatment) in Central and Eastern European (CEE) countries. Although some of the chemical treatment technologies are proven ones in North America, Scandinavia, and Germany, a host of factors, for example, the variations in composition and degree of pollution, the type of technologies in use, the type and mix of industrial and domestic sewage, and the amount of surface water, had meant that the viability of using CU in CEE countries was unknown. This report describes the first jar tests of CU conducted during the summer of 1993. The experiments show CU's ability to improve wastewater treatment plant performance and to potentially assist in the significant problem of overloaded treatment plants. Increased removal of BOD, TSS, and P in the primary stage of treatment is obtained at overflow rates above 1.5 m/h, using reasonably priced, local sources of metal salts in concentrations of 25 to 50 mg/l without polymers.


1999 ◽  
Vol 39 (8) ◽  
pp. 177-184 ◽  
Author(s):  
Derin Orhon ◽  
Seval Sözen ◽  
Erdem Görgün ◽  
Emine Ubay Çokgör ◽  
Nazik Artan

Coastal tourist areas should be classified as environmentally sensitive areas. Effective nutrient control should be implemented to safeguard the quality of receiving waters in these areas. In this context, the applicable discharge limitations are reviewed with specific reference to European directives and criteria developed for small coastal residential areas in Turkey are reported; wastewater characterization and its impact on treatment technology selection is reviewed; appropriate treatment technologies are evaluated in terms of selecting new applications and upgrading and retrofitting existing systems.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 182
Author(s):  
Kang Hyun Lee ◽  
Ye Won Jang ◽  
Hansol Kim ◽  
Jang-Seu Ki ◽  
Hah Young Yoo

Microalgae have been attracting attention as feedstock for biorefinery because they have various advantages, such as carbon fixation, high growth rate and high energy yield. The bioactive compounds and lutein contained in microalgae are known to be beneficial for human health, especially eye and brain health. In this study, in order to improve the recovery of bioactive extracts including lutein from Tetraselmis suecica with higher efficiency, an effective solvent was selected, and the extraction parameters such as temperature, time and solid loading were optimized by response surface methodology. The most effective solvent for lutein recovery was identified as 100% methanol, and the optimum condition was determined (42.4 °C, 4.0 h and 125 g/L biomass loading) by calculation of the multiple regression model. The maximum content of recovered lutein was found to be 2.79 mg/mL, and the ABTS radical scavenging activity (IC50) and ferric reducing antioxidant power (FRAP) value were about 3.36 mg/mL and 561.9 μmol/L, respectively. Finally, the maximum lutein recovery from T. suecica through statistical optimization was estimated to be 22.3 mg/g biomass, which was 3.1-fold improved compared to the control group.


Author(s):  
Hamed A. A. Omer ◽  
Sawsan M. Ahmed ◽  
Roshdy I. El-Kady ◽  
Aly A. El-Shahat ◽  
Mahmoud Y. El-Ayek ◽  
...  

Abstract Background Agriculture by-products are considered a great potential value for utilization by ruminants as well as rabbits. They usually can be the maintenance and part of the production requirements. However, in developing countries, as well as in Egypt, animals suffer from shortage of feeds that are continuously increasing in costs. In general, biological treatments were shown to be the most effective and improved chemical composition of rice straw or corn stalks. Method This work aimed to investigate the possible ways of utilizing rice straws or corn stalks in rabbit feeding. The field work is designed to study the effect of biological treatment of Pleurotus ostreatus cultivated on rice straws and Trichoderma reesei cultivated on corn stalks and replacing clover hay by rice straws and corn stalks at levels of 0, 33, 66, and 100% either without or with microbes adding. Seventy-eight New Zealand White (NZW) rabbits aged 4–5 weeks (565 ± 13.57 g) were randomly divided into thirteen equal experimental groups. Results Untreated rice straws or biologically treated with Pleurotus ostreatus increased their contents of crude protein (CP) by 178.75 and 224.5% and nitrogen-free extract (NFE) by 6.30 and 24.53, respectively. Meanwhile, crude fiber (CF) content was reduced by 31.32 and 56.75%, and organic matter content was decreased by 2.81 and 5.51%, respectively, in comparison with the raw rice straws. Also, biological treatment of rice straws caused a decrease in values of neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and hemicellulose contents in comparison with either raw or treated rice straws. Furthermore, biological treatment with Trichoderma reesei realized a decrease in organic matter (OM), CF, NDF, and ADF and increased CP and ash contents in corn stalks. NFE content of corn stalks was decreased as a result of treatment without or with Trichoderma reesei experimental rations by 11.95% and 3.82% compared to raw corn stalks (CS). Biological treatments with fungi significantly (P < 0.05) improved average daily gain (ADG) and feed conversion. ADG and feed conversion were significantly (P < 0.05) improved when rabbits were fed diets containing rice straw (RS) compared to that fed CS. Rabbits fed diets replaced clover hay (CH) with 33% or 66% of RS or CS significantly increased ADG compared to control and that replaced 100% of both RS and CS containing rations. Levels of replacing had no significant effect on their dry matter intake (DMI) values. The highest improvement in feed conversion was recorded with rabbits that received diets replaced 33% of berseem hay (BH) by RS or CS, followed by that replaced 66% of BH by RS or CS. There were significantly interactions between biological treatments (T), roughage source (S), and replacement levels (L) (T × S × L) only on ADG. The best fed conversion was realized by rabbits fed diet replaced BH with 33% of RS that are treated by Pleurotus ostreatus (4.05 g DMI/g gain). Rabbits fed 33% biologically treated rice straw with Pleurotus ostreatus showed the highest economic efficiency (179%) followed by rabbits that received 33% of both rice straws treated without Pleurotus ostreatus and rabbits that received corn stalks biologically treated with Trichoderma reesei (161%). Conclusion Biological treatments of rice straws by Pleurotus ostreatus or corn stalks by Trichoderma reesei were safe, and it improves their chemical analysis and improved both daily gain and feed conversion, decreasing the costing of diet formulation which consequently decreased the price of 1-kg live body weight.


2006 ◽  
Vol 134 (5) ◽  
pp. 1068-1073 ◽  
Author(s):  
M. G. BAKER ◽  
L. D. LOPEZ ◽  
M. C. CANNON ◽  
G. W. DE LISLE ◽  
D. M. COLLINS

New Zealand has a large reservoir of Mycobacterium bovis infection in wild and farmed animals. This study aimed to assess the extent of human infection with this organism and the potential contribution of these animal sources. Combined epidemiological and laboratory investigation of human tuberculosis cases over the period 1995–2002 showed that M. bovis accounted for 2·7% (54/1997) of laboratory-confirmed human tuberculosis cases, a rate of 0·2/100000 population. M. bovis isolates from humans (23) were typed using restriction endonuclease analysis (REA) and compared with isolates from wild and domestic animals (2600). Fourteen (61%) of the human isolates had REA patterns that were identical to patterns for isolates from cattle, deer, possums, ferrets, pigs, and occasionally cats. These results suggest a low level of ongoing M. bovis transmission from animal reservoirs to humans in New Zealand.


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