Abstract: The cumulative costs for O&M may represent as
much as 65%-90% of the turbine's investment cost. Nowadays the
cost effectiveness concept becomes a decision-making and
technology evaluation metric. The cost of energy metric accounts for
the effect replacement cost and unscheduled maintenance cost
parameters. One key of the proposed approach is the idea of
maintaining the WTs which can be captured via use of a finite state
Markov chain. Such a model can be embedded within a probabilistic
operation and maintenance simulation reflecting the action to be
done. In this paper, an approach of estimating the cost of O&M is
presented. The finite state Markov model is used for decision
problems with number of determined periods (life cycle) to predict
the cost according to various options of maintenance.
Abstract: Sewage sludge is a biomass resource that can create a
solid fuel and electricity. Utilizing sewage sludge as a renewable
energy can contribute to the reduction of greenhouse gases. In Japan,
the "National Plan for the Promotion of Biomass Utilization" and the
“Priority Plan for Social Infrastructure Development" were approved
at cabinet meetings in December 2010 and August 2012, respectively,
to promote the energy utilization of sewage sludge. This study
investigated costs and greenhouse gas emission in different sewage
sludge treatments with technologies for energy from sewage sludge.
Expenses were estimated based on capital costs and O&M costs
including energy consumption of solid fuel plants and biogas power
generation plants for sewage sludge. Results showed that the cost of
sludge digestion treatment with solid fuel technologies was 8% lower
than landfill disposal. The greenhouse gas emission of sludge
digestion treatment with solid fuel technologies was also 6,390t as
CO2 smaller than landfill disposal. Biogas power generation reduced
the electricity of a wastewater treatment plant by 30% and the cost by
5%.
Abstract: Sediment loads transfer in hydraulic installations and their consequences for the O&M of modern canal systems is emerging as one of the most important considerations in hydraulic engineering projects apriticularly those which are inteded to feed the irrigation and draiange schemes of large command areas such as the Dez and Mogahn in Iran.. The aim of this paper is to investigate the applicability of the vortex tube as a viable means of extracting sediment loads entering the canal systems in general and the water inatke structures in particulars. The Western conveyance canal of the Dez Diversion weir which feeds the Karkheh Flood Plain in Sothwestern Dezful has been used as the case study using the data from the Dastmashan Hydrometric Station. The SHARC software has been used as an analytical framework to interprete the data. Results show that given the grain size D50 and the canal turbulence the adaption length from the beginning of the canal and after the diversion dam is estimated at 477 m, a point which is suitable for laying the vortex tube.
Abstract: Food and fibre production in arid and semi-arid regions has emerged as one of the major challenges for various socio-economic and political reasons such as the food security and self-sufficiency. Productive use of the renewable water resources has risen on top ofthe decision-making agenda. For this reason, efficient operation and maintenance of modern irrigation and drainage schemes become part and parcel and indispensible reality in agricultural policy making arena. The aim of this paper is to investigate the complexity of operating and maintaining such schemes, mainly focussing on challenges which enhance and opportunities that impedsustainable food and fibre production. The methodology involved using secondary data complemented byroutine observations and stakeholders views on issues that influence the O&M in the Dez command area. The SPSS program was used as an analytical framework for data analysis and interpretation.Results indicate poor application efficiency in most croplands, much of which is attributed to deficient operation of conveyance and distribution canals. These in turn, are reportedly linked to inadequate maintenance of the pumping stations and hydraulic structures like turnouts,flumes and other control systems particularly in the secondary and tertiary canals. Results show that the aforementioned deficiencies have been the major impediment to establishing regular flow toward the farm gates which subsequently undermine application efficiency and tillage operationsat farm level. Results further show that accumulative impact of such deficiencies has been the major causes of poorcrop yield and quality that deem production system in these croplands uneconomic. Results further show that the present state might undermine the sustainability of agricultural system in the command area. The overall conclusion being that present water management is unlikely to be responsive to challenges that the sector faces. And in the absence of coherent measures to shift the status quo situation in favour of more productive resource use, it would be hard to fulfil the objectives of the National Economic and Socio-cultural Development Plans.
Abstract: In Algeria, liberalization reforms undertaken since the 1990s have resulted in negative effects on the development and management of irrigation schemes, as well as on the conditions of farmers. Reforms have been undertaken to improve the performance of irrigation schemes, such as the national plan of agricultural development (PNDA) in 2000 and the water pricing policy of 2005. However, after implementation of these policies, questions have arisen with regard to irrigation performance and its suitability for agricultural development. Hence, the aim of this paper is to provide insight into the profitability of irrigation during the transition period under current irrigation agricultural policies in Algeria. By using the method of farm crop budget analysis in the East Mitidja irrigation scheme, the returns from using surface water resources based on farm typology were found to vary among crops and farmers- groups within the scheme. Irrigation under the current situation is profitable for all farmers, including both those who benefit from subsidies and those who do not. However, the returns to water were found to be very sensitive to crop price fluctuations, particularly for non-subsidized groups and less so for those whose farming is based on orchards. Moreover, the socio-economic environment of the farmers contributed to less significant impacts of the PNDA policy. In fact, the limiting factor is not only the water, but also the lack of land ownership title. Market access constraints led to less agricultural investment and therefore to low intensification and low water productivity. It is financially feasible to recover the annual O&M costs in the irrigation scheme. By comparing the irrigation water price, returns to water, and O&M costs of water delivery, it is clear that irrigation can be profitable in the future. However, water productivity must be improved by enhancing farmers- income through farming investment, improving assets access, and the allocation of activities and crops which bring high returns to water; this could allow the farmers to pay more for water and allow cost recovery for water systems.
Abstract: Sedimentation is a hydraulic phenomenon that is
emerging as a serious challenge in river engineering. When the flow
reaches a certain state that gather potential energy, it shifts the
sediment load along channel bed. The transport of such materials can
be in the form of suspended and bed loads. The movement of these
along the river course and channels and the ways in which this could
influence the water intakes is considered as the major challenges for
sustainable O&M of hydraulic structures. This could be very serious
in arid and semi-arid regions like Iran, where inappropriate watershed
management could lead to shifting a great deal of sediments into the
reservoirs and irrigation systems. This paper aims to investigate
sedimentation in the Western Canal of Dez Diversion Weir in Iran,
identifying factors which influence the process and provide ways in
which to mitigate its detrimental effects by using the SHARC
Software.
For the purpose of this paper, data from the Dezful water authority
and Dezful Hydrometric Station pertinent to a river course of about 6
Km were used.
Results estimated sand and silt bed loads concentrations to be 193
ppm and 827ppm respectively. Given the available data on average
annual bed loads and average suspended sediment loads of 165ppm
and 837ppm, there was a significant statistical difference (16%)
between the sand grains, whereas no significant difference (1.2%)
was find in the silt grain sizes. One explanation for such finding
being that along the 6 Km river course there was considerable
meandering effects which explains recent shift in the hydraulic
behavior along the stream course under investigation. The sand
concentration in downstream relative to present state of the canal
showed a steep descending curve. Sediment trapping on the other
hand indicated a steep ascending curve. These occurred because the
diversion weir was not considered in the simulation model.