scholarly journals Assessing the Economic Feasibility of Integrated Waste to Use Systems for Uganda

2021 ◽  
Vol 8 ◽  
pp. 27-45
Author(s):  
Miria Frances Agunyo ◽  
Sarah Kizza-Nkambwe ◽  
Kukunda Elizabeth Bacwayo

Waste and sanitation Management is a major challenge in urban areas in Uganda where waste is composed of atleast 70% organic content and is basically collected and disposed of in landfills. While 90% of the sanitation facilities used are onsite systems often requiring additional treatment of sewage and faecal matter sewage yet faecal and sewage sludge treatment plants are few. The projected population increase is expected to further influence urbanization, increasing the need for basic waste and sanitation services. Integrated Waste to Use systems that consider combined management of organic waste streams i.e. biowaste, animal waste, sewage and faecal sludge, could be a viable solution for the urban areas. The systems which consist of a combination of anaerobic digestion, composting, incineration and solar drying technologies promote resource recovery in the form of biogas, briquettes and organic fertilizer. The economic feasibility of the Waste to Use systems was carried out and the results indicated that the feasibility of the systems was positively influenced by the inclusion of the anaerobic digestion process, which allowed for recovery of biogas and digestate as organic fertilizer. Furthermore, a combination of low system investment costs, increased revenues from resource recovery, consideration of equity capital of at least 30%, interest rate of at most 10% and fugitive emissions less than 7 % would positively influence the economic feasibility of the system alternatives.

Author(s):  
Abraham Amenay Zewde ◽  
Zifu Li ◽  
Zhou Xiaoqin

Abstract The global challenges that face sustainable sanitation services in developing countries are the lack of fecal sludge management; this is due to the rapid urbanization and population growth as it generates enormous quantities of fecal sludge. The extensive use of unimproved sanitation technologies is one of the main reasons for environmental and public health concerns. In dispersed rural areas, isolated slums or in urban areas where a sewerage system is costly, decentralized wastewater system can be used. Therefore centralized management of decentralized wastewater systems along with proper institutional framework treatment of fecal sludge can be used to enhance the economies of developing counties from resource recovery. The discovery of new ways to inactivate pathogens contained in human waste is key in improving access to sanitation worldwide and reducing the impact of conventional waste management processes on the environment. The entire FS management system should include on-site sanitary treatment methods, collection, and transportation of FS, treatment facilities as well as resource recovery or disposal of the treated end products. This review paper addresses the hygienization of fecal sludge and improved treatment technologies for safe reuse or disposal of the end products and the significant economic revenues attained from the treatments of fecal sludge.


2018 ◽  
Vol 2018 (4) ◽  
pp. 353-365
Author(s):  
David Parry ◽  
Cameron Clark ◽  
Corey Kliebert ◽  
Paul Steele

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3411
Author(s):  
Clara Fernando-Foncillas ◽  
Maria M. Estevez ◽  
Hinrich Uellendahl ◽  
Cristiano Varrone

Wastewater and sewage sludge contain organic matter that can be valorized through conversion into energy and/or green chemicals. Moreover, resource recovery from these wastes has become the new focus of wastewater management, to develop more sustainable processes in a circular economy approach. The aim of this review was to analyze current sewage sludge management systems in Scandinavia with respect to resource recovery, in combination with other organic wastes. As anaerobic digestion (AD) was found to be the common sludge treatment approach in Scandinavia, different available organic municipal and industrial wastes were identified and compared, to evaluate the potential for expanding the resource recovery by anaerobic co-digestion. Additionally, a full-scale case study of co-digestion, as strategy for optimization of the anaerobic digestion treatment, was presented for each country, together with advanced biorefinery approaches to wastewater treatment and resource recovery.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4292
Author(s):  
Lidia Lombardi ◽  
Barbara Mendecka ◽  
Simone Fabrizi

Industrial anaerobic digestion requires low temperature thermal energy to heat the feedstock and maintain temperature conditions inside the reactor. In some cases, the thermal requirements are satisfied by burning part of the produced biogas in devoted boilers. However, part of the biogas can be saved by integrating thermal solar energy into the anaerobic digestion plant. We study the possibility of integrating solar thermal energy in biowaste mesophilic/thermophilic anaerobic digestion, with the aim of reducing the amount of biogas burnt for internal heating and increasing the amount of biogas, further upgraded to biomethane and injected into the natural gas grid. With respect to previously available studies that evaluated the possibility of integrating solar thermal energy in anaerobic digestion, we introduce the topic of economic sustainability by performing a preliminary and simplified economic analysis of the solar system, based only on the additional costs/revenues. The case of Italian economic incentives for biomethane injection into the natural gas grid—that are particularly favourable—is considered as reference case. The amount of saved biogas/biomethane, on an annual basis, is about 4–55% of the heat required by the gas boiler in the base case, without solar integration, depending on the different considered variables (mesophilic/thermophilic, solar field area, storage time, latitude, type of collector). Results of the economic analysis show that the economic sustainability can be reached only for some of the analysed conditions, using the less expensive collector, even if its efficiency allows lower biomethane savings. Future reduction of solar collector costs might improve the economic feasibility. However, when the payback time is calculated, excluding the Italian incentives and considering selling the biomethane at the natural gas price, its value is always higher than 10 years. Therefore, incentives mechanism is of great importance to support the economic sustainability of solar integration in biowaste anaerobic digestion producing biomethane.


2017 ◽  
Vol 10 (5) ◽  
pp. 143
Author(s):  
Tongyuan Wang

This article proposes a systematic engineering for sustainable economic and ecologic development. This system is deemed to be applicable in any country of the world. The system aims to realize five important objectives: water source clearance, energy saving and emission reduction, renewable energy and organic fertilizer production, and ecological agriculture development, all in large scale and at low cost. The main conception of the new system to reach these goals is the replacement of the conventional sewage treatment approach with more efficient and more ecological process – the natural fermentation of the mixture of the urban sewage and agrarian wastes, such that water body clearance, including water de-eutrophication, green algae prevention and siltation dredging will all be accomplished at virtually a zero cost. Along with this process, the system can produce a vast amount of renewable energy and organic fertilizers, consequently ecological agriculture development in large scale can be realized. As a result, this system will greatly reduce the use of chemical fertilizers thus largely reduce the consumption of fossil energy and the related polluting emissions. This system is thus fully a circular economy model through full west-reuse processes, which ultimately will enhance our life quality with healthier food and living environment. The system is flexible and adaptable to be implemented in either small towns or megacities. The implementation and operation of this system will also benefits employment growth. Lastly, in terms of economic feasibility and profitability, millions to billions of dollars of annual revenue can be generated from the running of this system in a country.


2019 ◽  
Vol 180 ◽  
pp. 938-948 ◽  
Author(s):  
Zeng Huiru ◽  
Yan Yunjun ◽  
Federica Liberti ◽  
Bartocci Pietro ◽  
Francesco Fantozzi

2018 ◽  
Vol 13 (3) ◽  
pp. 513-523 ◽  
Author(s):  
J. Tolksdorf ◽  
P. Cornel ◽  
M. Wagner

Abstract The SEMIZENTRAL approach is an infrastructure solution for the challenges of high growth dynamics and resource scarcity in fast growing urban areas. The integration of water, wastewater, waste, and energy in one system increases resource efficiency. District-wise realization enables the infrastructure system to grow at the same rate as the city. The concept has been realized for the first time on a scale of 12,000 population equivalent in Qingdao, China. Greywater and blackwater are collected separately; treated greywater is reused for toilet flushing. Reclaimed blackwater is used for irrigation. The analyses of the wastewater composition reveal significant differences in comparison to design values as well as to literature values for greywater and blackwater. Unexpected user behaviour, as well as cross-connections, are likely reasons. The greywater and blackwater treatment processes in the Resource Recovery Center were adapted to the influent's characteristics, so that legal effluent limits are fulfilled, despite changes in influent quality. Small systems often show higher influent variability. Design data for systems with source separation are still lacking. Measurement campaigns in areas similar to the planning area are recommendable, but might not always be possible. In addition, there is a risk of cross-connections between blackwater and greywater, though this can be reduced. For these reasons, there is (possibly high) uncertainty regarding design values for greywater and blackwater. Correspondingly, the treatment processes need to be designed flexibly. For future implementation, technical risks deriving from source separation have to be weighed against the expected higher acceptance of reuse of treated greywater in households. Intra-urban reuse of total wastewater, in combination with extensive public relations programs, might be an alternative.


2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Ahmad Shobib

Cow manure can be used for making organic fertilizer because it contains nutrients such as Nitrogen (N), Phosphorus (P), and Potassium (K). Rice straw has a high C-Organic content. Adding straw compost will increase soil organic matter content. The study aims to determine the fermentation process that occurs so as to produce organic fertilize, know the effect of fermentation time and the effect of the composition of raw materials for cow manure and rice straw on the process of making organic fertilizer to the content of organic fertilizer according to SNI 7603 : 2018. The method use by aerobic fermentation is by mixing cow manure and rice straw and M-Dec bioactivators by comparison 3 : 1, 2 : 2,1 : 3 and fermentation time 7, 14, 21, 28 days. The parameters tested are C-organic, Nitrogen (N), C/N ratio, Phosphorus (P), and Potassium (K). The best quality organic fertilizer in the treatment of cow manure : rice straw with a ratio of 2 : 2 on the 28th day fermentation process namely C-organic content 34,63 %, C/N ratio is 25, macro nutrient content N+P2O5+K2O of 3,14 % that has met SNI 7763 : 2018. Keyword: M-Dec bioactivator, aerobic fermentation, cow manure, rice straw, C/N ratio


2020 ◽  
Vol 58 (5A) ◽  
pp. 190
Author(s):  
Khoi Diep Ngoc Vo

The paper presents the results of the evaluation of sludge decomposition ability from a municipal wastewater treatment plant by an aerobic process on the Mishimax device (MK-50). The principle of the process was based on the microorganisms activated by the bulking agent as a bio-carrier to decompose organics composition and increase the evaporation by heating. An average sludge amount of 30 kg/day was added into MK-50, with the moisture of 80.2 – 83.6 %, with the C/N ratio of around 22 - 35. The heated air with 50 oC in temperature was supplied into a rotary bioreactor during the experiment period. After every 30 days of fermentation, the results from three experiments showed that the sludge volume decreased from 83 - 85 %, the stabilization efficiency by dry weight of sludge reached at 32 - 39 %, corresponding to the average decomposition rate is 12 g/kg.day, the evaporation efficiency was more than 95 %. Sludge after stabilization process had the colour of brown-grey, pH of about 6.5 - 7.2, the humus particles with the size of less than 1 mm accounted for over 60 %, the evaluation of product indexes according to nutrients like TOC, T-N meet the standard of 10TCN 526:2002/BNN&PTNT. The stabilized sludge was used for growth plant test and compared to a market organic fertilizer under the same conditions of cultivation and monitoring. The initial results of this study were a basis for research of sludge treatment technology approaches to waste recycling orientation in urban areas in Vietnam.


2019 ◽  
Vol 69 (3) ◽  
pp. 238-247 ◽  
Author(s):  
Nils Kändler ◽  
Ivar Annus ◽  
Anatoli Vassiljev ◽  
Raido Puust

Abstract Stormwater runoff from urban catchments is affected by the changing climate and rapid urban development. Intensity of rainstorms is expected to increase in Northern Europe, and sealing off surfaces reduces natural stormwater management. Both trends increase stormwater peak runoff volume that urban stormwater systems (UDS) have to tackle. Pipeline systems have typically limited capacity, therefore measures must be foreseen to reduce runoff from new developed areas to existing UDS in order to avoid surcharge. There are several solutions available to tackle this challenge, e.g. low impact development (LID), best management practices (BMP) or stormwater real time control measures (RTC). In our study, a new concept of a smart in-line storage system is developed and evaluated on the background of traditional in-line and off-line detention solutions. The system is operated by real time controlled actuators with an ability to predict rainfall dynamics. This solution does not need an advanced and expensive centralised control system; it is easy to implement and install. The concept has been successfully tested in a 12.5 ha urban development area in Tallinn, the Estonian capital. Our analysis results show a significant potential and economic feasibility in the reduction of peak flow from dense urban areas with limited free construction space.


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