scholarly journals Sustainable Autarky of Food-Energy-Water

Meeting the demand for food, energy, and water to sustain the worldwide growth of urban population is a major challenge. Several recent reports have concluded that one approach to overcome this challenge is to recover and recycle resources within the food-energywater (FEW) nexus in urban settings. Urban wastewaters (UWW) are now being recognized as a resource, rich in nutrients and energy, rather than a waste stream that has to be treated and disposed of at the expense of significant energy input and associated environmental emissions. Reclaiming reusable water, nutrients, and energy from UWWs can contribute to autarky of FEW nexus and render the wastewater management process sustainable and potentially profitable. This paper presents a novel approach to treat UWW with the potential for high recovery of energy, nutrients, and water from UWW for use in food crop production. This approach entails cultivation of energy-rich algal biomass in primary-settled UWW followed by extraction of biocrude and nutrients from the algal biomass by hydrothermal liquefaction. A fraction of the recovered nutrients is recycled to boost biomass production while the rest can be stockpiled for use as fertilizer. Results from a pilot scale field study conducted at a local wastewater treatment plant confirmed that the algal system can achieve >80% removal of organic carbon, ammoniacal-nitrogen, and phosphates in UWW, meeting the respective discharge standards in a single step, with a batch process time of three days.

Author(s):  
Samar A. El-Mekkawi ◽  
Sayeda M. Abdo ◽  
Farag A. Samhan ◽  
Gamila H. Ali

Abstract Background Algal biomass fermentation is one of the promising alternatives for bioethanol production. The bioethanol yield relies on fermentation conditions as the algal biomass amount, the yeast volume (% v/v), and the fermentation time. In this work, algal biomass harvested from a pilot-scale high rate algal pond (HRAP) was fermented anaerobically using immobilized Saccharomyces cerevisiae (ATCC 4126). The HRAP was constructed at the Zenin wastewater treatment plant (WTP), Giza, Egypt. A separate hydrolysis fermentation process (SHF) was applied for algal biomass. The effect of the algal biomass amount, the yeast volume (% v/v), and the time of fermentation as three independent variables were studied simultaneously and analyzed statistically using Design-Expert software V6.0.8. Results The harvested algal biomass from HRAP contains 45% carbohydrates and was dominated by Microcystis sp. The results revealed that optimum bioethanol yield 18.57 g/L is achieved by fermenting 98.7 g/L algae using 15.09% of the volume immobilized yeast for 43.6 h with a 95% confidence interval. Conclusion Microalgae grown on wastewater are a promising source of bioethanol production. Maximizing the ethanol production is achieved by optimizing the fermentation parameters as algal biomass, fermentation time, and yeast volume percent. The simultaneous optimization of the parameters using a statistical program is an effective way to maximize the production and predict a model that describes the relationship between these parameters and their response. The prospective research is going to study the effect of these predicted parameters on continuous fermentation on the semi-pilot scale.


Author(s):  
Omar Alagha ◽  
Ahmed Allazem ◽  
Alaadin A. Bukhari ◽  
Ismail Anil ◽  
Nuhu Dalhat Mu'azu

The present study investigates the performance of a pilot-scale Sequencing Batch Reactor (SBR) process for the treatment of wastewater quality parameters, including turbidity, total suspended solids (TSS), total solids (TS), nitrogen (ammonia (NH3–N), nitrite (NO2−), and nitrate (NO3−), phosphate (PO43−), the chemical oxygen demand (COD), and the 5-day biological oxygen demand (BOD5), from municipal wastewater. Two scenarios, namely, pre-anoxic denitrification and post-anoxic denitrification, were investigated to examine the performance of a pilot-scale SBR on the wastewater quality parameters, particularly the nitrogen removal. The correlation statistic was applied to explain the effects of operational parameters on the performance of the SBR system. The results revealed that the post-anoxic denitrification scenario was more efficient for higher qualify effluent than the first scenario. The effluent concentrations of the targeted wastewater quality parameters obtained for the proposed SBR system were below those of the local standards, while its performance was better than that of the North Sewage Treatment Plant, Dharan, Eastern province, Kingdom of Saudi Arabia (KSA), in terms of the BOD5, COD, TN, and PO43- treatment efficiencies. These results indicated the suitability of SBR technology for wastewater treatment in remote areas in the KSA, with a high potential of reusability for sustainable wastewater management.


2006 ◽  
Vol 1 (4) ◽  
Author(s):  
Huub H.J. Cox ◽  
Steve Fan ◽  
Reza Iranpour

Terminal Island Treatment Plant converted its digesters to thermophilic operation with the objective to comply with the U.S. EPA Part 503 Biosolids Rule requirements for Class A biosolids. The following processes were tested: a) single-stage continuous; b) two-stage continuous; c) single-stage sequencing batch. Salmonella sp. were always non-detect in digester outflows (<3 MPN/4 g dry wt), whereas fecal coliform densities were usually below the Class A limit of 1000 MPN/g dry wt. However, the recurrence of fecal coliforms in post-digestion caused non-compliance with the Class A limit at the truck loading facility as the last point of plant control for compliance. After several design modifications of the post-digestion train, operation of the digesters as sequencing batch digesters according to the time-temperature requirement of Alternative 1 of the Part 503 Biosolids Rule achieved compliance for both Salmonella sp. and fecal coliforms at the last point of plant control (truck loading facility).


2000 ◽  
Vol 41 (1) ◽  
pp. 163-166 ◽  
Author(s):  
W. Gebert ◽  
P.A. Wilderer

The investigated effects of heating the filling material in trickling filters were carried out at the Ingolstadt wastewater treatment plant, Germany. Two pilot scale trickling filters were set up. Heat exchanger pipings were embedded in the filter media of one of these trickling filters, and the temperature in the trickling filter was raised. The other trickling filter was operated under normal temperature conditions, and was used as a control. The results clearly demonstrate that the performance of trickling filters cannot be constantly improved by heating the biofilm support media. A sustained increase of the metabolic rates did not occur. The decrease of the solubility of oxgen in water and mass transfer limitations caused by an increase of the biofilm thickness are the main reasons for that. Thus, the heating of trickling filters (e.g. by waste heat utilization) in order to increase the capacity of trickling filters under cold weather conditions cannot be recommended.


2010 ◽  
Vol 62 (8) ◽  
pp. 1965-1965
Author(s):  
S. Park ◽  
J. Lee ◽  
J. Park ◽  
I. Byun ◽  
T. Park ◽  
...  

Publisher‘s note. We regret that the published version of this article erroneously denoted the first author as corresponding author; in fact the formal corresponding author of this paper is Professor Taeho Lee, whose address is repeated below.


2021 ◽  
Vol 11 (4) ◽  
pp. 1788
Author(s):  
Thanh-Tri Do ◽  
Binh-Nguyen Ong ◽  
Tuan-Loc Le ◽  
Thanh-Cong Nguyen ◽  
Bich-Huy Tran-Thi ◽  
...  

In the production of astaxanthin from Haematococcus pluvialis, the process of growing algal biomass in the vegetative green stage is an indispensable step in both suspended and immobilized cultivations. The green algal biomass is usually cultured in a suspension under a low light intensity. However, for astaxanthin accumulation, the microalgae need to be centrifuged and transferred to a new medium or culture system, a significant difficulty when upscaling astaxanthin production. In this research, a small-scale angled twin-layer porous substrate photobioreactor (TL-PSBR) was used to cultivate green stage biomass of H. pluvialis. Under low light intensities of 20–80 µmol photons m−2·s−1, algae in the biofilm consisted exclusively of non-motile vegetative cells (green palmella cells) after ten days of culturing. The optimal initial biomass density was 6.5 g·m−2, and the dry biomass productivity at a light intensity of 80 µmol photons m−2·s−1 was 6.5 g·m−2·d−1. The green stage biomass of H. pluvialis created in this small-scale angled TL-PSBR can be easily harvested and directly used as the source of material for the inoculation of a pilot-scale TL-PSBR for the production of astaxanthin.


2021 ◽  
Vol 287 ◽  
pp. 112295
Author(s):  
Gulshan Kumar Sharma ◽  
Shakeel Ahmad Khan ◽  
Manoj Shrivastava ◽  
Ranjan Bhattacharyya ◽  
Anil Sharma ◽  
...  

2017 ◽  
Vol 77 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Yanjun Mao ◽  
Xie Quan ◽  
Huimin Zhao ◽  
Yaobin Zhang ◽  
Shuo Chen ◽  
...  

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.


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