scholarly journals Biogas Production from Food Residues—The Role of Trace Metals and Co-Digestion with Primary Sludge

Environments ◽  
2020 ◽  
Vol 7 (6) ◽  
pp. 42 ◽  
Author(s):  
Moshe Habagil ◽  
Alexander Keucken ◽  
Ilona Sárvári Horváth
Keyword(s):  
Methane Production ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Process Efficiency ◽  
Municipal Wastewater Treatment ◽  
Primary Sludge ◽  
Mixing Ratios ◽  
Feasible Option ◽  
Food Residues

The majority of municipal Wastewater Treatment Plants (WWTPs) in Sweden produce biogas from sewage sludge. In order to increase the methane production, co-digestion of internal sludge with Organic Fraction of Municipal Solid Waste (OFMSW) might be feasible in the future. The objective of this study was therefore to find a beneficial solution for the utilization of OFMSW at the WWTP in Varberg, Sweden. The effects of co-digesting primary sludge (PS) and OFMSW collected in the municipality, in different mixing ratios, were investigated by semi-continuous anaerobic digestion assays. Furthermore, the effects of the addition of a commercial trace elements mixture solution (CTES), available on the market in Sweden, were also examined. Co-digestion of OFMSW and PS resulted in specific methane yields of 404, 392, and 375 NmL CH4/g volatile solids (VS), obtained during semi-continuous operations of 301, 357 and 385 days, for the reactors fed with OMFSW:PS ratio of 4:1, 3:1, and 1:1, and at maximum organic loading rates (OLRs) achieved of 4.0, 4.0 and 5.0 gVS/L/d, respectively. Furthermore, mono-digestion of OFMSW failed already at OLR of 1.0 gVS/L/d, however, an OLR of 4.0 gVS/L/d could be achieved with addition of 14 µL/g VS Commercial Trace Element Solutions (CTES) leading to 363 mL CH4/g VS methane production. These experiments were running during 411 days. Hence, higher process efficiency was obtained when using co-digestion of OFMSW and PS compared to that of OFMSW in mono-digestion. Co-digestion is a more feasible option where a balanced Carbon/Nitrogen (C/N) ratio and nutrient supply can be maintained.

scholarly journals Ultrasonic pretreatment for anaerobic digestion of suspended and attached growth sludges

2019 ◽  
Vol 54 (4) ◽  
pp. 265-277 ◽  
Author(s):  
Peter Roebuck ◽  
Kevin Kennedy ◽  
Robert Delatolla
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Biofilm Reactor ◽  
Municipal Wastewater Treatment ◽  
Ultrasonic Pretreatment ◽  
Conventional Activated Sludge ◽  
Digestion Kinetics ◽  
The Impact

Abstract Anaerobic digestion (AD) is a proven technology for energy production from the stabilization and reduction of sewage waste. The AD and impact of ultrasonic pretreatment of four waste activated sludges (WASs) from conventional and three non-conventional municipal wastewater treatment plants were investigated. WAS from a conventional activated sludge (CAS) system, a rotating biological contactor (RBC), a lagoon, and a nitrifying moving-bed biofilm reactor (MBBR) were pretreated with ultrasonic energies of 800–6,550 kJ/kg total solids to illustrate the impact of sludge type and ultrasonic pretreatment on biogas production (BGP), solubilization, and digestion kinetics. The greatest increase in BGP over the control of pretreated sludge did not coincide consistently with greater sonication energy but occurred within a solubilization range of 2.9–7.4% degree of disintegration and are as follows: 5% ± 3 biogas increase for CAS, 12% ± 9 for lagoon, 15% ± 2 for nitrifying MBBR, and 20% ± 2 for RBC. The effect of sonication on digestion kinetics was inconclusive with the application of modified Gompertz, reaction curve, and first-order models to biogas production. These results illustrate the unique response of differing sludges to the same levels of sonication energies. This article has been made Open Access thanks to the kind support of CAWQ/ACQE (https://www.cawq.ca).

Carbon footprints of Scandinavian wastewater treatment plants

2013 ◽  
Vol 68 (4) ◽  
pp. 887-893 ◽  
Author(s):  
D. J. I. Gustavsson ◽  
S. Tumlin
Keyword(s):  
Wastewater Treatment ◽  
Carbon Footprint ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Municipal Wastewater Treatment ◽  
Carbon Footprints ◽  
Fossil Carbon

This study estimates the carbon footprints of 16 municipal wastewater treatment plants (WWTPs), all situated in Scandinavian countries, by using a simple model. The carbon footprint calculations were based on operational data, literature emission factors (efs) and measurements of greenhouse gas emissions at some of the studied WWTPs. No carbon neutral WWTPs were found. The carbon footprints ranged between 7 and 108 kg CO2e P.E.−1 year−1. Generally, the major positive contributors to the carbon footprint were direct emissions of nitrous oxide from wastewater treatment. Whether heat pumps for effluents have high coefficient of performance or not is extremely important for the carbon footprint. The choice of efs largely influenced the carbon footprint. Increased biogas production, efficient biogas usage, and decreased addition of external fossil carbon source for denitrification are important activities to decrease the carbon footprint of a WWTP.

scholarly journals Advanced Wastewater Treatment to Eliminate Organic Micropollutants in Wastewater Treatment Plants in Combination with Energy-Efficient Electrolysis at WWTP Mainz

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3599 ◽  
Author(s):  
Oliver Gretzschel ◽  
Michael Schäfer ◽  
Heidrun Steinmetz ◽  
Erich Pick ◽  
Kim Kanitz ◽  
...  
Keyword(s):  
Water Management ◽  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Automatic Frequency ◽  
Municipal Wastewater Treatment ◽  
Organic Micropollutants ◽  
Micropollutant Removal

To achieve the Paris climate protection goals there is an urgent need for action in the energy sector. Innovative concepts in the fields of short-term flexibility, long-term energy storage and energy conversion are required to defossilize all sectors by 2040. Water management is already involved in this field with biogas production and power generation and partly with using flexibility options. However, further steps are possible. Additionally, from a water management perspective, the elimination of organic micropollutants (OMP) is increasingly important. In this feasibility study a concept is presented, reacting to energy surplus and deficits from the energy grid and thus providing the needed long-term storage in combination with the elimination of OMP in municipal wastewater treatment plants (WWTPs). The concept is based on the operation of an electrolyzer, driven by local power production on the plant (photovoltaic (PV), combined heat and power plant (CHP)-units) as well as renewable energy from the grid (to offer system service: automatic frequency restoration reserve (aFRR)), to produce hydrogen and oxygen. Hydrogen is fed into the local gas grid and oxygen used for micropollutant removal via upgrading it to ozone. The feasibility of such a concept was examined for the WWTP in Mainz (Germany). It has been shown that despite partially unfavorable boundary conditions concerning renewable surplus energy in the grid, implementing electrolysis operated with regenerative energy in combination with micropollutant removal using ozonation and activated carbon filter is a reasonable and sustainable option for both, the climate and water protection.

scholarly journals SARS-CoV-2 Detection in Istanbul Wastewater Treatment Plant Sludges

2020 ◽  
Author(s):  
Bilge Alpaslan Kocamemi ◽  
Halil Kurt ◽  
Ahmet Sait ◽  
Fahriye Sarac ◽  
Ahmet Mete Saatci ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Waste Activated Sludge ◽  
Secondary Process ◽  
Virus Concentration ◽  
Municipal Wastewater Treatment ◽  
Primary Sludge

Following the announcement of SARS-CoV-2 worldwide pandemic spread by WHO on March 11, 2020, wastewater based epidemiology received great attention in several countries: The Netherlands [Medama et al., 2020; K-Lodder et al., 2020], USA [Wu et al., 2020; Memudryi et al., 2020], Australia [Ahmed et al., 2020], France [Wurtzer et al., 2020], China [Wang et al., 2020], Spain [Randazzo et al., 2020; Walter et al., 2020], Italy (La Rosa et al., 2020; Rimoldi et al., 2020) and Israel [Or et al., 2020], performed analysis in wastewaters by using different virus concentration techniques. Turkey took its place among these countries on 7th of May, 2020 by reporting SARS-CoV-2 RT-qPCR levels at the inlet of seven (7) major municipal wastewater treatment plants (WWTPs) of Istanbul [Alpaslan Kocamemi et al., 2020], which is a metropole with 15.5 million inhabitants and a very high population density (2987 persons/km2) and having about 65 % of Covid-19 cases in Turkey. Sludges that are produced in WWTPs should be expected to contain SARS-CoV-2 virus as well. There has not yet been any study for the fate of SAR-CoV-2 in sludges generated from WWTPs. Knowledge about the existing of SARS-CoV-2 in sludge may be useful for handling the sludge during its dewatering, stabilizing and disposal processes. This information will also be valuable in case of sludges that are used as soil conditioners in agriculture or sent to landfill disposal. In wastewater treatment plants, generally two different types of sludges are generated; primary sludge (PS) and waste activated sludge (WAS). PS forms during the settling of wastewater by gravity in the primary settling tanks. Little decomposition occurs during primary sludge formation. Since most of the inorganic part of the wastewater is removed in the earlier grit removal process, the PS consists of mainly organic material that settles. The PS is about 1-2 % solids by weight. In the biological treatment part of the WWTPs, the biomass that forms in the anaerobic, anoxic and oxic zones of the process is settled in final clarifiers by gravity and returned to the beginning of the biological process so that it is not washed off. The waste activated sludge (WAS) is the excess part of the biomass that grows in this secondary treatment process. It has to be removed from the process not to increase the mixed liquor suspended solids concentration (bacteria concentration) in the secondary process more than a fixed value. The WAS is about 0.6 - 0.9 % solids by weight. This work aims to find whether SARS-CoV-19 is present in the PS and WAS before it is dewatered and sent to anaerobic or aerobic digester processes or to thermal drying operations. For this purpose, on the 7th of May 2020, two (2) PS samples were collected from Ambarlı and Tuzla WWTPs, seven (7) WAS samples were collected from Terkos, Ambarlı, Atakoy I & II, Pasakoy II, Buyukcekmece and Tuzla I WWTPs. Polyethylene glycol 8000 (PEG 8000) adsorption [Wu et al., 2020] SARS-Cov-2 concentration method was used for SARS-CoV-2 concentration after optimization. [Alpaslan Kocamemi et al., 2020]. Real time RT-PCR diagnostic panel validated by US was used to quantify SARS-CoV-2 RNA in primary and waste activated sludge samples taken from WWTPs in Istanbul. All samples were tested positive. Titers of SARS-CoV-2 have been detected ranging copies between 1.17E4 to 4.02x104 per liter.

scholarly journals Feasibility and potential of separate anaerobic digestion of municipal sewage sludge fractions

Water SA ◽  
2020 ◽  
Vol 46 (1 January) ◽  
Author(s):  
Dilek Erdirencelebi ◽  
Cansu Bayhan
Keyword(s):  
Methane Production ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Substantial Reduction ◽  
Methane Yield ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Municipal Wastewater Treatment ◽  
Oil And Grease ◽  
Daily Production

Feasibility of the separate anaerobic stabilization of primary (PS) and secondary (SS) sludge fractions produced in municipal wastewater treatment plants (WWTP) was studied at volatile loading rates (VLR) of 0.57–2.05 and 0.27–0.57 kg VS/(m3∙d) for PS and SS, respectively, corresponding to 16–30 and 14–28 d of hydraulic retention time (HRT). Laboratory-scale semi-continuous anaerobic reactors were operated at 35°C.  The operational performance and quality of the final stabilized sludge were monitored. PS and SS showed opposite thickening abilities exhibiting a need for direct feeding of PS to the digesters. Biodegradability was obtained as 52(±1) and 40(±5)% volatile solid (VS) removal for PS and SS, respectively. Optimum VLR was determined according to the highest methane yield (specific methane production), VS reduction and dewaterability of the stabilised sludge. An inhibitory effect was observed at higher VLRs in PS digestion inducing a gradual reduction in the methane yield and daily production. High oil and grease content was subject to a substantial reduction in PS digestion showing a dependency on HRT. Conversely, a considerable degree of augmentation took place in the stabilised SS with no correlation to HRT at values lower than 30 d. Efficient reduction in the oil and grease content improved dewaterability in stabilised PS whereas high oil and grease content prevented an improvement for stabilised SS. Major benefits were obtained as lower HRT and high stability with higher methane production and fertilizing (N and P content) characteristics for digestion performance and stabilized SS, whereas direct feeding and higher HRT for PS digestion were determined as beneficial.  

scholarly journals Modification of municipal wastewater for improved biogas recovery

2020 ◽  
Vol 15 (3) ◽  
pp. 683-696
Author(s):  
Vaileth Hance ◽  
Thomas Kivevele ◽  
Karoli Nicholas Njau
Keyword(s):  
Anaerobic Digestion ◽  
Energy Demand ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Organic Content ◽  
Municipal Wastewater Treatment ◽  
Naoh Solution ◽  
Municipal Wastewater Treatment Plants

Abstract The energy demand, which is expected to increase more worldwide, has sparked the interest of researchers to find sustainable and inexpensive sources of energy. This study aims to integrate an energy recovering step into municipal wastewater treatment plants (MWWTPS) through anaerobic digestion. The anaerobic digestion of municipal wastewater (MWW), and then co-digestion with sugar cane molasses (SCM) to improve its organic content, was conducted at 25 °C and 37 °C. The results showed a substrate mixture containing 6% of SCM and total solids (TS) of 7.52% yielded a higher amount of biogas (9.73 L/L of modified substrate). However, chemical oxygen demand (COD) of the resulting digestate was high (10.1 g/L) and pH was not stable, and hence needed careful adjustment using 2 M of NaOH solution. This study recommends a substrate mixture containing SCM (2%) and TS (4.34%) having biogas production (4.97 L/L of modified substrate) for energy recovery from MWWTPS, since it was found to have more stable pH and low COD residue (1.8 g/L), which will not hold back the MWW treatment process. The annual generation of modified substrate (662,973 m3) is anticipated to generate about 16,241 m3 of methane, which produces up to 1.8 GWh and 8,193 GJ per annum.

scholarly journals Electron beam technology for biogas and biofertilizer generation at municipal resource recovery facilities

Nukleonika ◽  
2021 ◽  
Vol 66 (4) ◽  
pp. 213-219
Author(s):  
Andrzej G. Chmielewski ◽  
Marcin Sudlitz ◽  
Bumsoo Han ◽  
Suresh D. Pillai
Keyword(s):  
Electron Beam ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Resource Recovery ◽  
Microbial Pathogens ◽  
Municipal Wastewater Treatment ◽  
Beam System ◽  
Municipal Wastewater Treatment Plants ◽  
Wastewater Samples

Abstract In the era of circular economies, municipal wastewater treatment plants (WWTPs) are viewed as resource recovery facilities. At the very minimum, the targeted resources are water, biogas, and phosphorus. However, municipal wastewater streams (sludge and effluent) need to be adequately treated to eliminate the potential for the transmission of microbial pathogens including protozoa, bacteria, and viruses. This paper presents the results from a study demonstrating the use of electron beam technology for sludge hygenization and enhanced methane (biogas) production using municipal wastewater samples. Cogeneration of heat for fertilizer drying and granulation and electricity for powering the electron beam system are also demonstrated.

Co-digestion of press liquids of source-sorted municipal organic waste in anaerobic sludge treatment of municipal wastewater treatment plants

2016 ◽  
Vol 73 (12) ◽  
pp. 3080-3086 ◽  
Author(s):  
Johannes Effenberger ◽  
Lydia Jahn ◽  
Volker Kuehn
Keyword(s):  
Wastewater Treatment ◽  
Methane Production ◽  
Organic Waste ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Screw Press ◽  
Anaerobic Sludge ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plants

Abstract This paper describes a semi-continuous laboratory-scale investigation of a potential co-substrate for mesophilic anaerobic sludge digestion in a municipal wastewater treatment plant. A feed liquid produced from source-sorted municipal organic waste by pretreatment with a screw press was subjected to the investigation. Quantities produced in press trials as well as the composition of the feed liquid are presented. Mass balances for N, P and chemical oxygen demand are given in order to verify the methane production of the feed liquid in co-digestion with sewage sludge at mesophilic conditions. Hydraulic retention time of the reactors were 14.7 to 16 d and organic loading rates were 1.5 to 2.7 kg volatile solids (VS) per cubic metre per day. The pretreatment by screw press is compared to the production of feed liquids with pulper-based pretreatment processes. While the addition of the feed liquid increased methane production by about 345 ml CH4/g VSin, total solids of the feed liquid were reduced to about 63%. With respect to co-digestion at municipal wastewater treatment plants, several risks associated with the investigated feed liquid are outlined.

scholarly journals Feasibility and potential of separate anaerobic digestion of municipal sewage sludge fractions

Water SA ◽  
2020 ◽  
Vol 46 (1 January) ◽  
Author(s):  
Dilek Erdirencelebi ◽  
Cansu Bayhan
Keyword(s):  
Methane Production ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Substantial Reduction ◽  
Methane Yield ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Municipal Wastewater Treatment ◽  
Oil And Grease ◽  
Daily Production

Feasibility of the separate anaerobic stabilization of primary (PS) and secondary (SS) sludge fractions produced in municipal wastewater treatment plants (WWTP) was studied at volatile loading rates (VLR) of 0.57–2.05 and 0.27–0.57 kg VS/(m3∙d) for PS and SS, respectively, corresponding to 16–30 and 14–28 d of hydraulic retention time (HRT). Laboratory-scale semi-continuous anaerobic reactors were operated at 35°C.  The operational performance and quality of the final stabilized sludge were monitored. PS and SS showed opposite thickening abilities exhibiting a need for direct feeding of PS to the digesters. Biodegradability was obtained as 52(±1) and 40(±5)% volatile solid (VS) removal for PS and SS, respectively. Optimum VLR was determined according to the highest methane yield (specific methane production), VS reduction and dewaterability of the stabilised sludge. An inhibitory effect was observed at higher VLRs in PS digestion inducing a gradual reduction in the methane yield and daily production. High oil and grease content was subject to a substantial reduction in PS digestion showing a dependency on HRT. Conversely, a considerable degree of augmentation took place in the stabilised SS with no correlation to HRT at values lower than 30 d. Efficient reduction in the oil and grease content improved dewaterability in stabilised PS whereas high oil and grease content prevented an improvement for stabilised SS. Major benefits were obtained as lower HRT and high stability with higher methane production and fertilizing (N and P content) characteristics for digestion performance and stabilized SS, whereas direct feeding and higher HRT for PS digestion were determined as beneficial.  

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