scholarly journals Concentration of Municipal MBBR Effluent by FO for Resource Recovery: Batch Experiments in Side-Stream Configuration

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 278
Author(s):  
Willy Røstum Thelin ◽  
Edvard Sivertsen ◽  
Gema Raspati ◽  
Kamal Azrague ◽  
Herman Helness
Keyword(s):  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Loading Rate ◽  
Resource Recovery ◽  
High Rate ◽  
Organic Loading Rate ◽  
Particle Removal ◽  
Organic Loading ◽  
Particulate Fouling ◽  
Flux Decline

A novel approach for resource recovery includes forward osmosis (FO) as a concentration step in municipal wastewater treatment. The current study investigates different pre-treatment strategies including biological treatment with a moving-bed bioreactor (MBBR) at different loading rates and particle removal by filtration and sedimentation. Membrane performance and recovery potential for energy and nutrients were investigated in laboratory-scale FO experiments in batch mode using pre-treated municipal wastewater as feed and 35 g/L NaCl as a draw solution. Initial water fluxes were in the range of 6.3 to 8.0 L/(m2·h). The baseline fluxes were modelled to account for flux decline due to concentration effects and to enable the prediction of flux decline due to membrane fouling. Fouling-related flux decline varied from 0 to 31%. Both organic fouling and precipitation of CaCO3 and CaHPO4 were identified by using SEM–EDS. High-rate flushing resulted in complete flux recovery under most conditions. Scaling could be avoided by lowering the pH. Two operation strategies were tested to achieve this: (1) applying a bioreactor with a low organic loading rate to achieve high nitrification, and (2) adding a strong acid. A low organic loading rate and the use of additional particle removal were efficient measures that reduced organic/particulate fouling. The recovery potentials for COD and phosphorous in FO concentrate were close to 100%.

Co-digestion of microalga-bacteria biomass with papaya waste for methane production

2018 ◽  
Vol 78 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Glenda Cea-Barcia ◽  
Jaime Pérez ◽  
Germán Buitrón
Keyword(s):  
Enzymatic Activity ◽  
Municipal Wastewater ◽  
Loading Rate ◽  
High Rate ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Ammonium Concentration ◽  
Volatile Solid ◽  
Organic Loading ◽  
Total Volatile

Abstract The anaerobic co-digestion of microalga-bacteria biomass and papaya waste (MAB/PW) was evaluated under semi-continuous conditions. Microalgae-bacteria biomass was obtained from a high rate algal pond fed with municipal wastewater and artificially illuminated. The co-digestion of MAB/PW was evaluated using a 1:1 (w/w) ratio and an organic loading rate of 1.1 ± 0.1 g COD/L/d. Enzymatic activity assays of papain were performed in the feeding to determine the activity of this enzyme in the substrate mixture. A methane yield of 0.55 L CH4/gVS and 68% of total volatile solid removal were observed. The volumetric productivity was 0.30 ± 0.03 L CH4/L/d with a methane content of 71%. It was observed that papaya waste was a suitable co-substrate because it maintained a low ammonium concentration, decreasing the risk of inhibition due to ammonia and then increasing the methane yield of the microalgae-bacteria biomass compared to the biomass alone. The pretreatment effect by the addition of papaya waste on the microalgae-bacteria biomass was supported by the papain activity remaining in the substrate.

scholarly journals Performance of AnMBR in Treatment of Post-consumer Food Waste: Effect of Hydraulic Retention Time and Organic Loading Rate on Biogas Production and Membrane Fouling

2021 ◽  
Vol 8 ◽  
Author(s):  
Javkhlan Ariunbaatar ◽  
Robert Bair ◽  
Onur Ozcan ◽  
Harish Ravishankar ◽  
Giovanni Esposito ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Food Waste ◽  
Membrane Fouling ◽  
Loading Rate ◽  
Biogas Production ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Side Stream ◽  
Removal Efficiencies

Anaerobic digestion of food waste (FW) is typically limited to large reactors due to high hydraulic retention times (HRTs). Technologies such as anaerobic membrane reactors (AnMBRs) can perform anaerobic digestion at lower HRTs while maintaining high chemical oxygen demand (COD) removal efficiencies. This study evaluated the effect of HRT and organic loading rate (OLR) on the stability and performance of a side-stream AnMBR in treating diluted fresh food waste (FW). The reactor was fed with synthetic FW at an influent concentration of 8.24 (± 0.12) g COD/L. The OLR was increased by reducing the HRT from 20 to 1 d. The AnMBR obtained an overall removal efficiency of >97 and >98% of the influent COD and total suspended solids (TSS), respectively, throughout the course of operation. The biological process was able to convert 76% of the influent COD into biogas with 70% methane content, while the cake layer formed on the membrane gave an additional COD removal of 7%. Total ammoniacal nitrogen (TAN) and total nitrogen (TN) concentrations were found to be higher in the bioreactor than in the influent, and average overall removal efficiencies of 17.3 (± 5) and 61.5 (± 3)% of TAN and TN, respectively, were observed with respect to the bioreactor concentrations after 2 weeks. Total phosphorus (TP) had an average removal efficiency of 40.39 (± 5)% with respect to the influent. Membrane fouling was observed when the HRT was decreased from 7 to 5 d and was alleviated through backwashing. This study suggests that the side-stream AnMBR can be used to successfully reduce the typical HRT of wet anaerobic food waste (solids content 7%) digesters from 20 days to 1 day, while maintaining a high COD removal efficiency and biogas production.

Effect of organic loading rate on a wastewater treatment process combining moving bed biofilm and membrane reactors

2005 ◽  
Vol 51 (6-7) ◽  
pp. 421-430 ◽  
Author(s):  
E. Melin ◽  
T. Leiknes ◽  
H. Helness ◽  
V. Rasmussen ◽  
H. Ødegaard
Keyword(s):  
Membrane Fouling ◽  
Loading Rate ◽  
Biofilm Reactor ◽  
Cod Removal ◽  
High Rate ◽  
Organic Loading Rate ◽  
Membrane Pore ◽  
Moving Bed ◽  
Loading Rates ◽  
Removal Efficiencies

The effect of moving bed biofilm reactor (MBBR) loading rate on membrane fouling rate was studied in two parallel units combining MBBR and membrane reactor. Hollow fiber membranes with molecular weight cut-off of 30 kD were used. The HRTs of the MBBRs varied from 45 min to 4 h and the COD loading rates ranged from 4.1 to 26.6 g COD m−2 d−1. The trans-membrane pressure (TMP) was very sensitive to fluxes for the used membranes and the experiments were carried out at relatively low fluxes (3.3–5.6 l m−2 h−1). Beside the test with the highest flux, there were no consistent differences in fouling rate between the low- and high-rate reactors. Also, the removal efficiencies were quite similar in both systems. The average COD removal efficiencies in the total process were 87% at 3–4 h HRT and 83% at 0.75–1 h HRT. At high loading rates, there was a shift in particle size distribution towards smaller particles in the MBBR effluents. However, 79–81% of the COD was in particles that were separated by membranes, explaining the relatively small differences in the removal efficiencies at different loading rates. The COD fractionation also indicated that the choice of membrane pore size within the range of 30 kD to 0.1 μm has very small effect on the COD removal in the MBBR/membrane process, especially with low-rate MBBRs.

scholarly journals A CRITICAL REVIEW ON THE EFFECT OF FEED TO INOCULUM RATIO ON BIOGAS DIGESTION

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
M Kalyani ◽  
Shalini Suran ◽  
P Ramya
Keyword(s):  
Particle Size ◽  
Municipal Wastewater ◽  
Loading Rate ◽  
Synergistic Effects ◽  
Considerable Effect ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Successful Operation ◽  
Start Up ◽  
Biogas Digestion

This paper primarily focuses on the effect of feed to inoculum ratio on biogas digestion; and outlines the various feeds, inoculums, and synergistic effects of the combination of inoculums by referring to the literature. The Start-up of an anaerobic digestion system is highly critical and pivotal for the successful operation of an anaerobic digester. For this purpose, a certain amount of inoculum is added to the digester along with the substrate to provide the necessary microorganisms to initiate the digestion process. The ratio and the type of inoculum used substantially affect the rate of biodegradation and the lag time. The degradation of substrate depends on the concentration of microorganisms. When food waste was considered as the feed it was found that factors such as waste oil content, the addition of alkaline buffer, particle size, organic loading rate had a considerable effect on the feed to inoculum ratio. Studies considering some other feeds such as animal by products from piggery slaughterhouses, poultry slaughterhouse wastes, agro-industrial waste, anaerobically digested sludge obtained from municipal wastewater, and dewatered digestate cake were also compared. Hence, the objective of this study is to offer an integrated view of the appropriate feed and the inoculum under the effect of various other essential parameters. The major performance indicators from this study were found to be particle size of inoculum, organic loading rate, the addition of alkaline buffer, F/I ratio, and structure of inoculum

Impact of Organic Loading Rate and DO on Filamentous Bulking Sludge and the Study of its Characteristics in Membrane Bioreactor

2010 ◽  
Vol 113-116 ◽  
pp. 1280-1284 ◽  
Author(s):  
Yu Tian ◽  
Xin Ying Su ◽  
Lin Chen ◽  
Tian Ling Jiang
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Loading Rate ◽  
Organic Loading Rate ◽  
Filamentous Bacteria ◽  
Organic Loading ◽  
High Substrate Concentration ◽  
Filamentous Bulking ◽  
And Control ◽  
The Impact

The membrane fouling behaviors and fouling mechanism of filamentous bulking sludge in membrane bioreactor (MBR) have been reported in recent studies. However, few studies have been conducted towards the causes and control of filamentous bulking sludge in MBR. In order to make clear the conditions of filamentous bacteria overgrowth in MBR, the impact of DO and organic loading rate on filamentous growth and its characteristics were investigated in this paper. The results showed that overgrowth of filamentous bacteria occurred under a relatively high substrate concentration (organic loading rate was 0.61 KgCOD/(KgMLSS•d), and DO was above 2 mg/L) in MBR. Nutrient removal effect can not be deteriorated under filamentous bulking sludge, with average 95, 57 and 92% removal efficiencies of COD, TN and TP respectively. The particle size of filamentous sludge was larger than that of normal sludge and the filamentous bacteria produced more SMP and EPS than floc forming bacteria.

scholarly journals Change of foulant concentration in an anaerobic membrane bioreactor

2020 ◽  
Author(s):  
Susumu Hasegawa ◽  
Genki Murakami ◽  
Ryosuke Takagi ◽  
Hideto Matsuyama
Keyword(s):  
Liquid Chromatography ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Loading Rate ◽  
Membrane Bioreactors ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Excess Sludge ◽  
Anaerobic Membrane Bioreactors ◽  
High Rejection

Abstract Anaerobic membrane bioreactors (AnMBRs) have many advantages, such as producing methane gas for energy generation and little excess sludge. However, membrane fouling is a serious problem because the foulant, which causes the membrane to foul, may get rejected by the membrane and accumulate in the reactor, resulting in an acceleration of membrane fouling. However, there is no information related to a change in the foulant concentration in an AnMBR. Therefore, we examined the changes in the foulant concentration in the reactor, related to membrane fouling in an AnMBR. For the influent, reactor solution, and effluent, the concentration of each component of the foulant was analyzed by using a liquid chromatography-organic carbon detector (LC-OCD). It was found that fouling in the AnMBR was closely related to the components in the reactor, and the main foulant of the ultrafiltration (UF) membrane was biopolymers (BPs). BP accumulated in the reactor because of a high rejection by the UF membrane. However, once the BP accumulated in the reactor was biodegraded, the concentration of BP decreased with time even under a high organic loading rate of 1.9kg TOC/m3/day.

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