Field study on N2O emission from subsurface wastewater infiltration system under variable loading rates and drying-wetting cycles

2017 ◽  
Vol 76 (8) ◽  
pp. 2158-2166 ◽  
Author(s):  
Ying-Hua Li ◽  
Hai-Bo Li ◽  
Xin-Yang Xu ◽  
Si-Yao Xiao ◽  
Si-Qi Wang ◽  
...  
Keyword(s):  
Field Study ◽  
Conversion Rate ◽  
Oxygen Demand ◽  
N2o Emission ◽  
Conversion Ratio ◽  
Gas Chromatograph ◽  
Variable Loading ◽  
N2o Production ◽  
Loading Rates ◽  
Operation Conditions

In this field study, the impacts of influent loadings and drying-wetting cycles on N2O emission in a subsurface wastewater infiltration (SWI) system were investigated. N2O emitted under different operation conditions were quantified using static chamber and gas chromatograph techniques. N2O conversion rate decreased from 6.6 ± 0.1% to 2.7 ± 0.1% with an increase in hydraulic loading (HL) from 0.08 to 0.24 m3/m2·d. By contrast, N2O conversion rate increased with increasing pollutant loading (PL) up to 8.2 ± 0.5% (PL 4.2 g N/m2·d) above which conversion rate decreased, confirming that N2O production was under the interaction of nitrification and denitrification. Taking into consideration the pollutants (chemical oxygen demand (COD), NH4+-N, NO3−-N and total nitrogen (TN)) removal ratio and N2O emission, optimal loading ranges and drying-wetting modes were suggested as HL 0.08–0.12 m3/m2·d, PL 3.2–3.7 g N/m2·d and 12 h:12 h, respectively. The results revealed that in SWI systems, conversion ratio of influent nitrogen to N2O could be between 4.5% and a maximum of 7.0%.

scholarly journals Assessment of the Effect of Remediation Strategies on the Environmental Quality of Aquaculture Ponds in Marilao and Meycauayan, Bulacan, Philippines

2018 ◽  
Vol 8 (20) ◽  
Author(s):  
John Vincent R. Pleto ◽  
Mark Dondi M. Arboleda ◽  
Jessica F. Simbahan ◽  
Veronica P. Migo
Keyword(s):  
Oxygen Demand ◽  
River System ◽  
The Philippines ◽  
Conversion Ratio ◽  
Feed Conversion Ratio ◽  
Culture Period ◽  
Vetiver Grass ◽  
Feed Conversion ◽  
Remediation Strategies ◽  
Aquaculture Ponds

Background. Water quality in the Marilao-Meycauayan-Obando river system (MMORS) of Bulacan, the Philippines, is of great concern due to the pollution load from local industries. The river system is currently used as a source of water for the aquaculture industry in Bulacan. Objectives. In order to address organic and heavy metal pollution, several remediation strategies were tested in aquaculture ponds along the river system. Strategies such as phytoremediation (vetiver grass pontoons), application of probiotics and zeolite (with filtration as pre-treatment) were utilized in ponds to decrease or remove toxic pollutants in water and sediments. Methods. Two sites were chosen as the pilot remediation sites – ponds in Barangay Nagbalon, Marilao and Barangay Liputan, Meycauayan, Bulacan. Pond bottom preparation was done to improve the condition of the pond bottom sediments before stocking by adding zeolite. Physicochemical parameters of water such as dissolved oxygen (DO), temperature, pH, salinity, ammonia, phosphate, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were monitored throughout the culture period. Heavy metals in sediments and fish were monitored. Fish parameters such as average body weight and feed conversion ratio were determined. Results. The DO levels were below recommended levels in the morning and reached a supersaturated level in the afternoon. Ammonia and COD levels were above recommended limits. A decreasing trend was observed for ammonia levels in treatment ponds. In terms of the growth of milkfish, the pond with probiotics showed the highest growth and better feed conversion ratio in Nagbalon and in the phytoremediation pond in Liputan. Percentage survival of milkfish was much higher at Liputan. Copper, chromium, lead and manganese were detected in pond sediments. After application of zeolite, there was a decrease in lead levels throughout the culture period. Conclusions. The different remediation studies were compared in terms of cost, effectivity and application and phytoremediation (vetiver grass pontoons) was determined to be the most cost-effective remediation strategy. Competing Interests. The authors declare no competing financial interests.

Fenton degradation of Cartap hydrochloride: identification of the main intermediates and the degradation pathway

2015 ◽  
Vol 72 (7) ◽  
pp. 1198-1205 ◽  
Author(s):  
Kaixun Tian ◽  
Cuixiang Ming ◽  
Youzhi Dai ◽  
Kouassi Marius Honore Ake
Keyword(s):  
Aqueous Medium ◽  
Flue Gas ◽  
High Performance ◽  
Oxygen Demand ◽  
Nitrogen Monoxide ◽  
Degradation Pathway ◽  
Gas Chromatograph ◽  
Gas Analyzer ◽  
Fenton System ◽  
Long Chain

The advanced oxidation of Cartap hydrochloride (Cartap) promoted by the Fenton system in an aqueous medium was investigated. Based on total organic carbon, chemical oxygen demand and high-performance liquid chromatography, the oxidation of Cartap is quite efficient by the Fenton system. Its long chain is easily destroyed, but the reaction does not proceed to complete mineralization. Ion chromatography detection indicated the formation of acetic acid, propionic acid, formic acid, nitrous acid and sulfuric acid in the reaction mixtures. Further evidence of nitrogen monoxide and sulfur dioxide formation was obtained by using a flue gas analyzer. Monitoring by gas chromatograph-mass spectrometer demonstrated the formation of oxalic acid, ethanol, carbon dioxide, and l-alanine ethylamide. Based on these experimental results, plausible degradation pathways for Cartap mineralization in an aqueous medium by the Fenton system are proposed.

Tilapia rearing with high rate algal pond effluent: ammonia surface loading rates and stocking densities effects

2018 ◽  
Vol 78 (1) ◽  
pp. 49-56
Author(s):  
I. A. Sánchez ◽  
R. K. X. Bastos ◽  
E. A. T. Lana
Keyword(s):  
Weight Gain ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
High Rate ◽  
Surface Loading ◽  
Loading Rates ◽  
Total Weight Gain ◽  
Low Weight ◽  
Total Ammonia

Abstract In two pilot-scale experiments, fingerlings and juvenile of tilapia were reared in high rate algal pond (HRAP) effluent. The combination of three different total ammonia nitrogen (TAN) surface loading rates (SLR1 = 0.6, SLR2 = 1.2; SLR3 = 2.4 kg TAN·ha−1·d−1) and two fish stocking densities (D1 = 4 and D2 = 8 fish per tank) was evaluated during two 12-week experiments. Fingerlings total weight gain varied from 4.9 to 18.9 g, with the highest value (equivalent to 0.225 g·d−1) being recorded in SLR2-D1 treatment; however, high mortality (up to 67%) was recorded, probably due to sensitivity to ammonia and wide daily temperature variations. At lower water temperatures, juvenile tilapia showed no mortality, but very low weight gain. The fish rearing tanks worked as wastewater polishing units, adding the following approximate average removal figures on top of those achieved at the HRAP: 63% of total Kjeldahl nitrogen; 54% of ammonia nitrogen; 42% of total phosphorus; 37% of chemical oxygen demand; 1.1 log units of Escherichia coli.

Anaerobic co-digestion of winery waste and waste activated sludge: assessment of process feasibility

2013 ◽  
Vol 69 (2) ◽  
pp. 269-277 ◽  
Author(s):  
C. Da Ros ◽  
C. Cavinato ◽  
F. Cecchi ◽  
D. Bolzonella
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Waste Activated Sludge ◽  
Organic Loading ◽  
Operational Conditions ◽  
Loading Rates ◽  
Thermophilic Conditions ◽  
Soluble Chemical Oxygen Demand

In this study the anaerobic co-digestion of wine lees together with waste activated sludge in mesophilic and thermophilic conditions was tested at pilot scale. Three organic loading rates (OLRs 2.8, 3.3 and 4.5 kgCOD/m3d) and hydraulic retention times (HRTs 21, 19 and 16 days) were applied to the reactors, in order to evaluate the best operational conditions for the maximization of the biogas yields. The addition of lee to sludge determined a higher biogas production: the best yield obtained was 0.40 Nm3biogas/kgCODfed. Because of the high presence of soluble chemical oxygen demand (COD) and polyphenols in wine lees, the best results in terms of yields and process stability were obtained when applying the lowest of the three organic loading rates tested together with mesophilic conditions.

scholarly journals The Concept of Wastes to Energy Using Sugary Wastes

2012 ◽  
Vol 9 ◽  
pp. 57-62
Author(s):  
Fiza Sarwar ◽  
Wajeeha Malik ◽  
Muhammad Salman Ahmed ◽  
Harja Shahid
Keyword(s):  
Volatile Fatty Acids ◽  
Loading Rate ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Sugar Mills ◽  
Anaerobic Sludge Blanket

Abstract: This study was designed using actual effluent from the sugary mills in an Up-flow Anaerobic Sludge Blanket (UASB) Reactor to evaluate treatability performance. The reactor was started-up in step-wise loading rates beginning from 0.05kg carbon oxygen demand (COD)/m3-day to 3.50kg-COD/m3-day. The hydraulic retention time (HRT) was slowly decreased from 96 hrs to eight hrs. It was observed that the removal efficiency of COD of more than 73% can be easily achieved at an HRT of more than 16 hours corresponding to an average organic loading rate (OLR) of 3.0kg-COD/m3-day, at neutral pH and constant temperature of 29°C. The average VFAs (volatile fatty acids) and biogas production was observed as 560mg/L and 1.6L/g-CODrem-d, respectively. The average methane composition was estimated as 62%. The results of this study suggest that the treatment of sugar mills effluent with the anaerobic technology seems to be more reliable, effective and economical.DOI: http://dx.doi.org/10.3126/hn.v9i0.7075 Hydro Nepal Vol.9 July 2011 57-62

Ear Dominance and Telephone Sales

1997 ◽  
Vol 85 (2) ◽  
pp. 451-457 ◽  
Author(s):  
Adrian Furnham ◽  
Simon Richardson ◽  
Tony Miller
Keyword(s):  
Retrospective Study ◽  
Individual Differences ◽  
Field Study ◽  
Conversion Rate ◽  
Sales Performance ◽  
Personal Preference ◽  
Sales Teams ◽  
Ear Dominance ◽  
Percentage Conversion

In a field study, three equally sized sales teams used one of three head-sets—left, right, both ears—for a day's selling of insurance by telephone. This had no effect on sales In a retrospective study of records, daily sales performance including the percentage conversion rate for sales divided by the number of calls and the number and duration of calls was related to preference for type of head-set. Sales were markedly influenced by the choice of head-set. People who chose to wear the left earpiece significantly out-sold the others wearing right and stereohead-sets. Neither the number of incoming calls nor the time spent on the telephone were influenced by the choice of head-set. When sales are analysed in terms of individual differences in personal preference for type of head-set, those who chose the left ear had an advantage. Forced use of the left, versus right ear or both ears for one day had no effect.

scholarly journals Performance of Anaerobic Digestion of Acidified Palm Oil Mill Effluent under Various Organic Loading Rates and Temperatures

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2432
Author(s):  
Muhammad Arif Fikri Hamzah ◽  
Peer Mohamed Abdul ◽  
Safa Senan Mahmod ◽  
Azratul Madihah Azahar ◽  
Jamaliah Md. Jahim
Keyword(s):  
Anaerobic Digestion ◽  
Palm Oil ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Microbial Community Analysis ◽  
Palm Oil Mill Effluent ◽  
Methane Formation ◽  
Organic Loading ◽  
Loading Rates ◽  
Palm Oil Mill

This study compared the performance of thermophilic and mesophilic digesters of an anaerobic digestion system from palm oil mill effluent (POME), in which temperature is a key parameter that can greatly affect the performance of anaerobic digestion. The digesters were incubated at two distinct temperatures of 55 and 37 °C, and operated with varying organic loading rates (OLRs) of 2.4, 3.2, and 4.0 g COD/L.d by altering the chemical oxygen demand (COD) of acidified POME during feeding. The results indicated that the performance of anaerobic digestion increased as the OLR increased from 2.4 to 4.0 g COD/L.d. At the OLR of 4.0 g COD/L.d, the thermophilic condition showed the highest methane yield of 0.31 ± 0.01 L/g COD, accompanied by the highest COD removal and volatile solid reduction, which were found to be higher than the mesophilic condition. Microbial community analysis via denaturing gradient gel electrophoresis (DGGE) revealed that Methanothermobacter sp. emerges as the dominant microbe, which is known to utilize the carbon dioxide pathway with hydrogen acting as an electron donor for methane formation

Anaerobic treatment of proteinaceous wastewater under mesophilic and thermophilic conditions

1999 ◽  
Vol 40 (1) ◽  
pp. 77-84 ◽  
Author(s):  
H. H. P. Fang ◽  
D. Wai-Chung Chung
Keyword(s):  
Bacterial Species ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Batch Tests ◽  
Thermophilic Conditions ◽  
Anaerobic Sludge Blanket ◽  
Hydrolysis Of

Experiments were conducted in two 2.8 liter UASB (upflow anaerobic sludge blanket) reactors treating proteinaceous wastewaters at 37° and 55°C with 9 hours of hydraulic retention. Results showed that the mesophilic reactor consistently removed 83.5-85.1% of COD (chemical oxygen demand) at loading rates ranging 8-22 g COD l−1 d−1 (corresponding to 3000-8250 mg l−1 of proteinaceous COD in wastewater), whereas the thermophilic reactor removed only 68.5-82.7%. At 32 g COD l−1 d−1 (i.e. 12000 mg COD l−1), the removal efficiencies were lowered to 75.7% in the mesophilic reactor and 65.1% in the thermophilic reactor. At 42 g COD l−1 d−1, severe sludge washout occurred in the mesophilic reactor; at the same loading rate, the thermophilic reactor removed only 53.8% of COD even though sludge washout was under control. The degradation rate in the both reactors was limited by the initial hydrolysis of proteins. However, batch tests showed that thermophilic sludge had slightly higher methanogenic activities than mesophilic sludge in treating proteins and intermediate acids, except propionate. The sludge yields in mesophilic and thermophilic reactors were 0.066 and 0.099 g VSS g COD−1, respectively. Observations by scanning electron microscopy indicated that both types of sludge granules were of irregular shape. There was little noticeable difference between the two granules; both had neither a layered microstructure nor a predominant bacterial species.

N2O producing capability of nitrosomonas europaea, nitrobacter winogradskyi and alcaligenes faecalis

1997 ◽  
Vol 36 (10) ◽  
pp. 65-72 ◽  
Author(s):  
Yuhei Inamori ◽  
Xiao-Lei Wu ◽  
Motoyuki Mizuochi
Keyword(s):  
Nitrosomonas Europaea ◽  
Alcaligenes Faecalis ◽  
N2o Emission ◽  
Mixed Cultures ◽  
Ammonia Oxidizer ◽  
Experimental Conditions ◽  
N2o Production ◽  
Pure Cultures ◽  
Pva Gel ◽  
Different Cultures

Nitrosomonas europaea, Nitrobacter winogradskyi and Alcaligenes faecalis—typical ammonia-oxidizer, nitrite-oxidizer and heterotrophic nitrifier were immobilized in PVA gel and employed in the study. Continuous experiments were conducted in their pure and mixed cultures with DO concentrations in the cultures kept at 4, 2, 0.5 mg·l−1. Comparisons among N2O emission from different cultures were made to show their N2O producing capabilities. Results showed that: compared with N. europaea and A. faecalis, N. winogradskyi produced negligible N2O. On the other hand, N. europaea had the highest N2O producing ability. Unit N. europaea produced N2O 18–53 times higher than unit A. faecalis did. However, due to the higher population of A. faecalis, N2O production of the A. faecalis culture was higher than that of the N. europaea culture when DO concentration in the cultures was 2 mg·l−1; whereas, N2O yields of the A. faecalis culture were smaller than those of the N. europaea culture at DO concentrations of 4 and 0.5 mg·l−1. N2O emitted from most the mixed cultures was lower than that from pure cultures under the experimental conditions.

The effect of a vertical flow filter bed on a hybrid constructed wetland system

2005 ◽  
Vol 51 (9) ◽  
pp. 137-144 ◽  
Author(s):  
A. Noorvee ◽  
E. Põldvere ◽  
Ü. Mander
Keyword(s):  
Constructed Wetland ◽  
Flow System ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Vertical Flow ◽  
Efficient Removal ◽  
Loading Rates ◽  
Purification Efficiency ◽  
Wetland System ◽  
Filter Bed

Data from 18 sampling wells in Kodijärve horizontal subsurface flow (HSSF) constructed wetland (CW) (South Estonia) is presented and differences in purification efficiencies inside the HSSF CW are calculated. Temporarily anaerobic conditions in the Kodijärve HSSF system did not allow efficient removal of BOD7, NH4-N, Ntot and Ptot. In 2002 a vertical subsurface flow filter was constructed to enhance aeration. The design of the system was based simply on the oxygen demand of the wastewater and on the aeration potential of vertical flow wetlands. The vertical flow system has shown satisfactory results. The purification efficiency of BOD7 in the Kodijärve CW has improved significantly and there has been a slight increase in purification efficiencies of NH4-N and Ntot. On the ohther hand, the removal efficiency of Ptot has decreased significantly. Although, the mass loading rates have increased, mass removal rates of all four parameters have improved significantly. Nevertheless, optimization of the constructed wetland system is essential in order to meet effluent standards during wintertime.

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