590471
research-article2015
WMR0010.1177/0734242X15590471Waste Management & ResearchSheinbaum et al.
Original Article
Biodiesel from waste cooking oil in Mexico City
Waste Management & Research 2015, Vol. 33(8) 730–739 © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0734242X15590471 wmr.sagepub.com
Claudia Sheinbaum1, Marco V Balam2, Guillermo Robles1, Sebastian Lelo de Larrea1 and Roberto Mendoza1
Abstract The aim of this article is to evaluate the potential use of biodiesel produced from waste cooking oil in Mexico City. The study is divided in two main areas: the analysis of a waste cooking oil collection pilot project conducted in food markets of a Mexico City region; and the exhaust emissions performance of biodiesel blends measured in buses of the Mexico City public bus transportation network (RTP). Results from the waste cooking oil collection pilot project show that oil quantities disposed depend upon the type of food served and the operational practices in a cuisine establishment. Food markets’ waste cooking oil disposal rate from fresh oil is around 10%, but with a very high standard deviation. Emission tests were conducted using the Ride-Along-Vehicle-EmissionsMeasuring System in two different types of buses while travelling a regular route. Results shows that the use of biodiesel blends reduces emissions only for buses that have exhaust gas recirculation systems, as analysed by repeated measure analysis of variance. The potential use in Mexico City of waste cooking oil for biodiesel is estimated to cover 2175 buses using a B10 blend. Keywords Biodiesel, waste cooking oil, food markets, emissions, Mexico City
Introduction In general, waste cooking oil (WCO) can be defined as an oilbased substance consisting of edible vegetable matter that has been used in the preparation of foods and is no longer suitable for human consumption (Kalam et al., 2011). Fats and vegetable oils are mixtures of triacylglycerols, composed of fatty acids and glycerol. During the deep-frying cooking process, triacylglycerols are oxidised and polymerised, producing polar compounds like free short-chain fatty acids, mono- and di-glycerides, aldehydes, ketones, polymers, and cyclic and aromatic compounds (DGF, 2012). Some of these degradation products have been linked to different human ailments when ingested (DGF, 2011). For this reason, the deep-fry cooking process generates WCO no longer suitable for consumption. Nevertheless, oil and grease are among the most stable of organic compounds that are not easily decomposed biologically (Stoll and Gupta, 1997). The discharge of WCO into drains or sewers provokes blockages, and if dumped in municipal solid waste landfills or into municipal sewage treatment plants, it creates operational problems along with pollution of water and soil (Talens Peiró et al., 2008). Mexico has federal and local regulations for the fat content of wastewater disposal (Diario Oficial de la Federación, 1997; Gaceta Oficial del Distrito Federal, 2012), however; the enforcement of the regulation is weak. The same case occurs with WCO management plans, considered in the local law of solid wastes (Gaceta Oficial del Distrito Federal, 2003). For this reason it is
important not only to regulate, but also to generate alternatives and incentives for WCO management. There are several options for the collection and treatment of oil and grease residues once they have been discharged into the drain. The most common is the grease trap, which avoids water pollution but maintains the problem of the final disposal. A different approach is to separate WCO at its source and develop collecting systems for recycling. There are several cities in the world that have developed this approach (Schneider and Ragossnig, 2013; Sheinbaum-Pardo et al., 2013; Wang and Wang, 2013). WCO can be used in soap manufacture and oleo chemical industries, and can also be used as the main raw material to produce biodiesel. The simplest process to produce biodiesel from vegetable oil (and methanol) is a base-catalysed transesterification that produces methyl esters and glycerine (Nas and Berktay, 2007). Biodiesel can be blended with diesel and used in many different concentrations, but biodiesel blends higher than B20
1Instituto
de Ingenieria, Universidad Nacional Autónoma de México, Mexico DF, Mexico 2Ambientalis Environmental Consulting, Mexico DF, Mexico Corresponding author: Claudia Sheinbaum, Instituto de Ingenieria, Universidad Nacional Autónoma de México, Ciudad Universitaria, México DF 04510, Mexico. Email: [email protected]
Downloaded from wmr.sagepub.com by guest on November 14, 2015
731
Sheinbaum et al. (20% biodiesel) require special handling and engine modifications (United States Environmental Protection Agency, 2010). One of the main concerns of using biodiesel blends from WCO is the air pollution that can caused by the burning of this fuel. Several authors have studied exhaust engine emissions using biodiesel blends as fuel. Some studies report that biodiesel decreases the tailpipe emissions of particulate matter (PM), carbon monoxide (CO), and volatile organic compounds, yet more controversy has been manifested on nitrogen oxide (NOx) emissions (Basha et al., 2009; Can, 2014; Giakoumis et al., 2012; Kalam et al., 2011; Mandal et al., 2011; Verhaeven et al., 2005; Yaakob et al., 2013). For this reason, any project that considers the use of biodiesel from WCO in a large scale would require a deep analysis, especially if it is going to be developed in urban areas with air quality problems. In this article, we present a case study developed in food markets of a Mexico City region. The study was conducted for several purposes: (a) to evaluate problems and barriers in the development of a WCO collection programme in markets and restaurants of Mexico City; (b) to quantify an average rate of WCO disposal in relation to fresh oil; and (c) to evaluate exhaust engine emissions of biodiesel from WCO blends in Mexico City buses.
Methodology WCO collection The study was conducted in a city area called Delegación Cuauhtémoc. It is one of the 16 political districts of the city. It has 530 thousand inhabitants, but receives more than 3 million people every day. It includes downtown Mexico City where most of the federal and local government offices are based. It produces 4.6% of the national gross domestic product, and it concentrates 36% of urban equipment and 40% of the cultural infrastructure of the city (Instituto Nacional de Estadística y Geografía, 2010). Delegación Cuauhtémoc has 29 food markets that embrace 1505 small restaurants. The WCO collection programme for food markets, which lasted over a year, consisted of four stages: (a) division of work and collection logistics; (b) education and training for restaurant owners and workers; c) collection follow-up and survey application; d) measurement of WCO disposal rate. In the WCO collection campaign included three teams. The first team led by the university was in charge of the programme coordination, education, training, application, and analysis of surveys and measurements. The private producer of biofuel was in charge of WCO collection, and officials of the Cuauhtémoc District were in charge of establishing communication between the university group and the private enterprise, with restaurants owners and market administrators. Education and training for cuisine owners and workers focused on four areas: (a) a general overview of the health effects of over-fried oil; (b) harmful effects of sewer blockages; (c) the use of WCO for biodiesel production; and (d) the procedure to collect and dispose of WCO. The restaurants collected WCO in a
Figure 1. WCO container.
small container that was deposited in a larger market container designed exclusively for WCO (Figure 1). After the first training, two surveys were conducted. The first one was applied in 316 restaurants (out of 1505), which corresponded to a sample of a 95% confidence level and 5% confidence interval. The objectives of these surveys were: (a) find the willingness to participate in the WCO collection programme; and (b) estimate the average amount of fresh oil used per costumer. A second survey was conducted in 127 restaurants that were participating actively in the programme (out of 219), which corresponded to a sample of a 95% confidence level and 5.5% confidence interval. The objective of this survey was to estimate the rate of WCO disposal. Because the results of the second survey had a very high dispersion, a direct measurement of the volume of WCO disposal was carried out in 19 restaurants. Three measurements were developed for each restaurant. The measurements consisted in quantifying the fresh oil that was to be used in 1 week. Additionally, we asked the owner to collect the WCO and store it during the week. The volume of the fresh oil as well as the volume of the WCO was measured every week for three different weeks.
Biodiesel production Biodiesel is produced in a small private plant. The production process started with the recovery of WCO from restaurants and households. Once the WCO was collected, it is filtered in order to separate solids, and then transformed into biodiesel by the transesterification process (Sheinbaum-Pardo et al., 2013). Biodiesel is tested according to the ASTM International standard D6751 (ASTM, 2015).
Emission testing Most research on biodiesel emissions have focused on the comparison between sources of biodiesel and petro-diesel in laboratory settings, in contrast, our measurements were carried out in the most natural settings possible, using a Ride-Along-VehicleEmissions-Measuring (RAVEM) System in a route that simulated the normal conditions of the public transport system (Weaver and Balam-Almanza, 2001).
Downloaded from wmr.sagepub.com by guest on November 14, 2015
732
Waste Management & Research 33(8)
Table 1. RTP buses by technology and model year. Model
2001
2002
2004
2006
2009
EPA-98 EPA-04 EURO-V EURO-IV Total
282
340
103
282
282
340
103
282
250 30 21 301
Note: Although some buses are more than 10 years old, they will continue to be in operation because of lack of funds for bus substitution.
The measurements were developed in September 2013, for two blends, B10 and B20, in buses of the public city-owned transport company called RTP (Red de Transporte de Pasajeros: Passenger Transport Network). CO2, CO, NOx, and PM were measured, but CO2 emissions were also accounted using a different methodology (Sheinbaum-Pardo et al., 2013). With 1308 buses (Table 1), RTP represents about 14% of all diesel passenger urban buses in the city. The average distance travelled by a RTP bus is 200 km per day and the average fuel economy is 2 km L-1 (Red de Transporte de Pasajeros, 2013). Two types of bus technology were measured: EPA-98 and EPA-04. These technologies correspond to the US Federal (EPA) emission standards for heavy-duty diesel truck and bus engines for 1998 and 2004 (United States Environmental Protection Agency, 2015), the latest emission standard required for the bus to have exhaust gas recirculation systems. Emission measurements were carried out using the RideAlong-Vehicle-Emissions-Measuring System (RAVEM), which was designed to maintain proportional sampling during transient variations in engine speed, load, and exhaust flow rate. RAVEM, based on the principle of constant volume sampling (CVS), measures gaseous and particulate exhaust emissions from diesel, and alternative fuel engines while riding along a vehicle. A schematic of RAVEM system can be found in Weaver and BalamAlmanza (2001) and Weaver and Petty (2004). As in all CVS systems, the pollutant concentration in the diluted exhaust leaving the dilution tunnel is proportional to the pollutant mass flowrate in the raw exhaust sample entering the tunnel. Realtime emissions of CO, CO2, and NOx can be thus determined by measuring the concentrations of these pollutants in the dilute exhaust. CO and CO2 concentrations were measured with a California Analytical Instruments (CAI) Model ZRH-2 NDIR analyser; and NOx concentrations were measured with a CAI 400S-HCLD heated chemo-luminescent analyser. For particulate matter measurements (PM), samples of the diluted exhaust and filtered dilution air were taken from the downstream and upstream ends of the dilution tunnel and analysed in laboratory, considering the discount of PM air content (Weaver and Petty, 2004).
Quality assurance The operation procedures include some measures of quality assurance (QA). Two key QA procedures are CO2 recovery and fuel consumption. During the CO2 recovery procedure, CO2 is injected from a pressurised cylinder to the dilution tunnel. At the
end of the procedure, CO2 measures are compared with the changed weight of the cylinder. Fuel consumption QA compares the fuel mass consumed during the tests, with fuel mass calculated from the mass balance of CO and CO2 emissions. Table 2 shows results of QA tests.
Procedure Buses and fuels. Six buses of two different technologies were selected for exhaust emission measurements: three EPA-98 and three EPA-04, all of them in well-maintained operative conditions. All six buses were measured for 100% petro-diesel (B0) as a baseline; and B10 and B20 blends. Three sets of measurements were taken to assure statistical robustness. Diesel was obtained from the RTP station service that buys fuel from the Mexican state-owned company Pemex. According to current fuel standards, diesel sulphur content is 15 ppm (Diario Oficial de la Federación, 2006). Route, weight simulation, and testing procedures. A test cycle was designed to follow a route that simulated the normal conditions of the RTP buses. The test cycle bus route was 8.3 km long, and had 22 bus stops of 10 s each. Overall, it took 45 min to transit. Buses were tested under regular traffic conditions from 8 a.m. to 6 p.m. Water containers weighting 4.5 t were used to simulate a load of 70% of the bus maximum capacity. The same driver drove the buses for every test. All buses were tested three times for all three types of fuel mix (B0, B10, and B20). Once a bus was ready for testing, the measurement equipment was connected and calibrated, and then the filters for PM were inserted. Testing was carried out on the predetermined route for 45 min, if the route was finished before time, the bus would wait in idle until the established time was reached. The bus speed was determined by the contiguous traffic. Once testing was terminated, gas samples were measured and PM filters were removed and sent to the laboratory for analysis. Figures 2 and 3 show pictures of this measurement set up.
Results and discussion WCO collection project The education–training programme was conducted for those interested in the project (it was not mandatory to attend). The programme registered personnel and owners of 452 restaurants of 28 food markets (which represented 41% of the total). After 2 months, and two visits of the team to all participants, only 121 restaurants of 16 markets remained (Table 3), which represented 27% of those who assisted in the education–capacitation programme, and only 8% of the food markets of the area of study. The main reason for the poor participation was the lack of encouragement from the market administration to follow the programme. A first survey to estimate the new edible oil bought per costumer per day, was applied to 316 restaurants. Results are presented in Table 4. A second survey to estimate the WCO rate over new oil was conducted for some the restaurants that participated in the project (121). Results are shown in Figure 4. Because of the dispersion of the sample, extreme numbers were taken out of the final results
Downloaded from wmr.sagepub.com by guest on November 14, 2015
733
Sheinbaum et al. Table 2. QA RAVEM tests. Test
Test type
Fuel estimation (mass balance) (g)
Fuel consumption (measured) (g)
%
MX1113 MX1125 MX1193 MX1194
Fuel recovery Fuel recovery CO2 recovery CO2 recovery
869 378 52 51
870 385 55 50
99 97 95 102
Figure 2. RAVEM on board.
Figure 3. Water containers on board.
(above 35%); Table 5 presents new results. As shown, the standard deviation is nearly the value of the average (9.3% ±8%). For this reason, a direct measurement was conducted. Details are explained in the methodology section. Measurements were taken from 19 restaurants out of four food markets. For each restaurant, three volume measurements were taken (one week each). As shown, measurements were not possible in all the restaurants. Results are surprisingly similar to those of the second survey (Table 6). The rate of WCO from new oil resulted in 10.8% ±9.6%. Results show that oil quantities released or disposed depended upon the type of food served and the operational practices in a cuisine establishment. In the case of food markets in Mexico City, it is between 2% and 20%, with an average of 10%.
Table 3. Participants after 2 months.
RAVEM: Ride-Along-Vehicle-Emissions-Measuring.
Emission tests
Number
Food market
1 2
San Joaquin anexo Tepito 60 (ropa y telas ) Melchor Ocampo Lagunilla zona San Lucas Insurgentes La Dalia San Juan Arcos de Belen Dos de Abril Abelardo l. rodriguez ( zona ) Martinez de la Torre zona Bugambilia Francisco Sarabia Isabel la Catolica San Cosme Pequeño comercio
3 4 5 6 7 8 9 10 11
Emission results for each vehicle are presented as the arithmetic average of all three measurements for each fuel type tested: B0, B10, and B20. Measurements made with B0 served as a baseline to which comparisons of B10 and B20 were made. When test results exceeded 20% for PM and 15% for other pollutants, they were eliminated from averaging. Nevertheless, arithmetic averages contain at least two measurements. The results described below are organised according to the bus engine technology.
EPA-04 Table 7 and Figure 5 show a summary of the emission results of each of the EPA-04 buses tested. Emissions are reported in grams per kilometer for PM, NOx, CO2, and CO, along with an
12 13 14 15 16 Total
Participation of restaurants
% of total
7 5
58 100
33 23 30 11 10 28
76 56 66 84 45 62
16 11
57 30
12
23
10 4 5 6 8 219
62 26 33 10 50 55
Case study developed from February to September 2014.
estimation of fuel consumption. Furthermore an estimation of relative change is also depicted. As shown, all three EPA-04 vehicles reduced 66% of PM emissions when using B10, and 36% when using B20. It is difficult to understand why the lower concentration of biodiesel
Downloaded from wmr.sagepub.com by guest on November 14, 2015
734
Waste Management & Research 33(8)
presents larger reductions, since it was expected that B20, having less sulphur than B10 and B0, would present less particulate formation; however, these results are consistent in all three vehicles. NOx reductions were of 4% and 8% for B10 and B20, respectively, also consistent in all three vehicles. Table 4. New edible oil bought per costumer per day in food markets. Restaurants where survey was applied Average number of costumers per week Average volume of new oil bought per week Average amount of new oil per costumer per week Standard deviation
316 350 13.75 L 0.06 L 0.01 L
Case study developed from February to September 2014.
EPA-98
140%
Table 9 and Figure 6 show a summary of the emission results of each of the EPA-98 buses tested. Emissions are reported in the same manner as the EPA-04 emission results above. As shown, instead of reductions, in the case of EPA-98 buses, measures
120%
WCO/new oil
CO2 emissions (directly related to fuel consumption) were reduced by 6% with the use of B10 and by 5% with the use of B20. This suggests that biodiesel is a very interesting option to explore in the whole vehicle fleet. CO results, although illustrative, are of little impact since diesel vehicles emit very little quantities of this gas. We conducted a repeated measures multivariate analysis of variance (ANOVA) to estimate the extent to which observed changes in emissions were significant. Table 8 summarises these results. As shown, only measurements of NOx and CO presented significant reductions in passenger buses using the EPA-04 technology.
100% 80% 60% 40%
Table 5. Estimation of WCO from new oil based on survey results.
20% 0%
0
20
40
60 80 Restaurants
100
120
140
Figure 4. Results of second survey: WCO rate from new oil. WCO: waste cooking oil.
Valid surveys WCO rate Standard deviation
108 9.3% 8.0%
WCO: waste cooking oil.
Table 6. Volume measurements (WCO out of new oil). Restaurant Measurement 1 New oil (L) WCO (L) Rate 1 9.8 2 7.5 3 34.5 1 24.0 2 7.5 3 4 9.0 1 2 3 4 10.0 5 7.0 6 1 1.8 2 3 4 10.0 5 9.0 6 18.0 Average Standard deviation
0.9 2.4 0 0.9 2.4
Measurement 2
Measurement 3
New oil (L) WCO (L) Rate
New oil (L) WCO (L)
1.0 1.0
0.5
9.1% 10.7 32.0% 3.0 24.0 3.7% 32.0% 12.0 6.0 44.4% 6.0 12.0 5.0 6.0 11.6% 5.0 17.7% 18.0 3.6 27.8% 9.0
0.3 0.5 1.5
7.5 2.5% 13.4 5.6% 8.3% 9.0
4
1.2 1.2
Average Rate
New oil (L) WCO (L) Rate
9.4% 10.8 33.3% 6.0 30.0 21.0 3.7% 7.5
0.9 0.9
8.3% 10.4 15.0% 5.5
0.9 1.4
3.4 0.3
16.1% 15.0 4.0% 9.0
1.4 1.0
2.9 1.9
48.3% 29.8%
7.0 9.2
2.7 1.8
0.4 0.3
6.7% 5.0%
0.1 0.1 0.1
1.9% 1.2% 0.9%
0.7 0.1
18.3% 6.0 13.3% 6.3 28.8% 8.3% 6.0 10.0% 5.0 4.2% 18.0 9.7% 2.7 10.8 11.7 9.3% 0.4% 6.3
0.6
9.5%
1.0
11.1% 12.0
0.2
1.7%
6.0 6.7 21.5 3.2 10.8 11.7 7.5 9.9 9.0 13.0
0.5 0.7 1.0 0.3 0.3 0.1 0.7 0.3 0.5 0.9
0.4 1.1 1.6 1.4 0.5 0.5 0.8 0.4 0.0
WCO: waste cooking oil.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
8.9% 26.1% 9.6% 11.5% 38.1% 19.1% 7.5% 10.0% 4.7% 7.9% 2.8% 0.9% 9.3% 3.4% 5.6% 6.9% 10.8% 9.6%
735
Sheinbaum et al. Table 7. Summary of EPA-04 emission results. Bus–blend
5143–BO 5143–B10 5143–B20 5108–BO 5108–B10 5108–B20 5091–BO 5091–B10 5091–B20 Average B0 Average B10 Average B20
Distance travelled (km)
Emissions (g km-1) PM
σ
CO2
σ
NOx
σ
CO
σ
8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3
0.60 0.19 0.53 0.47 0.17 0.21 0.37 0.13 0.18 0.48 0.16 0.31
0.28 0.03 0.09 0.18 0.01 0.01 0.03 0.03 0.01
1612 1387 1517 1462 1381 1349 1290 1331 1270 1455 1366 1378
133 38 7 41 20 42 50 21 10
15.2 14.0 13.5 16.0 15.4 14.8 15.9 15.6 15.1 15.7 15.0 14.4
1.0 0.2 0.2 0.4 0.4 0.1 0.2 0.1 0.2
9.7 5.9 9.5 5.7 4.4 5.1 5.1 3.4 5.1 6.8 4.6 6.5
0.9 0.5 0.2 0.4 0.5 0.0 0.3 0.1 0.7
Figure 5. EPA-04 results of test emissions.
show increases in PM (59% and 15% on average for B10 and B20, respectively), and marginal increases in NOx (8% and 3% for B10 and B20 blends, respectively). In the case of CO2, there is a 17% increase for B10 and a 3% increase for B20. Again, we conducted a repeated measures multivariate ANOVA to estimate the extent to which observed changes in emissions were significant. Table 10 summarises these results. As shown, no measurements presented significant differences in passenger buses using the EPA-98 technology.
Potential of biodiesel from WCO and related emissions Sheinbaum et al. (2013) estimated WCO production in Mexico, using vegetable oil sales and WCO recovery rate. A gross
estimation for Mexico City WCO availability for biodiesel production can be calculated based on population. Therefore, biodiesel production from WCO for a certain year will be: BD MC = WCOMC *η (1)
and:
WCO MC = VO M / Pop M * Pop MC * Rr (2)
where BDMC is the biodiesel production potential in Mexico City, η is the recovery efficiency of WCO to biodiesel production (in volume), WCOMC is the waste cooking oil available for biodiesel in Mexico City, VOM is the vegetable oil sales in the country, PopM is the country´s population, PopMC is the
Downloaded from wmr.sagepub.com by guest on November 14, 2015
736
Waste Management & Research 33(8)
Mexico City population, and Rr is the recovery ratio of WCO to fresh vegetable oil consumption (from food markets based on this study). Table 11 shows values for equations (1) and (2) for the year 2012. Assuming that all the WCO produced in Mexico City is utilised for biodiesel production, the biodiesel potential from WCO in the City is 7938 m3 based on 2012 data. RTP public buses (SMA, 2010a) circulate an average distance of 73,000 km per year and have an average fuel economy of 2 km L-1. If a B10 blend is used, potentially, 1087 public buses in Mexico City could use biodiesel from a WCO blend. If B20 is used, then potentially 544 buses can use biodiesel from WCO. Considering a recovery ratio (Rr) of 20%, the number of buses is multiplied by 2. The emission reduction potentials are shown in Table 12 and Table 13 only for buses with EPA-04 technologies and beyond. In contrast, the CO, NOx, PM, and CO2 emissions registered in year 2010 from diesel passenger buses in the Mexico City Metropolitan area were: CO: 46,493 t; NOx: 25,311 t; PM10 +PM2.5: 700 t; CO2: 2,159,207 t (Secretaría del Medio Ambiente del Gobierno del Distrito Federal, 2010a, 2010b).
Table 8. Summary of the repeated measures multivariate ANOVA. Measure
F
sig.
PM NOx CO CO2
2.197 4.800 4.632 0.10
0.176 0.044 0.029 0.960
The significance (sig.) shown depicts the Greenhouse–Geisser corrected value. PM: particulate matter.
Conclusions and recommendations This article presents the outcomes of a pilot project of WCO collection developed in food markets from an area of Mexico City. It also presents the results of exhaust emissions performance of biodiesel blends measured in buses of the City’s public bus transportation network (RTP). Based on these results, an estimation of WCO availability for biodiesel production in Mexico City was estimated. Results from the WCO collection pilot project show that oil quantities released or disposed depend upon the type of food served and the operational practices in a cuisine establishment. A disposal rate of WCO from fresh oil was 10.8%, with a standard deviation of 9.6%. In order to achieve more participation of restaurant owners, an increased participation of market and governmental authorities is recommended. Results show that biodiesel blends from WCO should not be used for buses with technologies EPA-98 and earlier, because emissions of PM and NOx might increase. Design differences between EPA-98 and EPA-04 engines could explain these results. In contrast to an EPA-98 engine, an EPA-04 engine counts with an exhaust gas recirculation system. This system was originally designed to reduce NOx emissions. In engines with this system, the exhaust gas is cooled and recycled into the motor to dilute the air/fuel mix, and thus, the quantity of oxygen entering the combustion chamber. This has an effect of temperature reduction in the chamber, which consequently reduces the formation of NOx (Kreso et al., 1998). For technologies that use exhaust gas recirculation systems, such as the EPA-04 buses, the best blend for CO reductions was B10 and for NOx reductions was B20. Results were analysed by a repeated measures multivariate ANOVA to estimate the extent to which observed changes in emissions were significant The potential use in Mexico City of WCO for biodiesel is estimated to cover 2175 buses using a B10 blend. This would
Table 9. Summary of EPA-98 emission results (results from field tests). Bus-blend
1115-BO 1115-B10 1115-B20 1367-BO 1367-B10 1367-B20 1127-BO 1127-B10 1127-B20 Average B20 Average B10 Average B20
Distance travelled (km)
σ
8.3 8.3 8.3 8.3 8.0 8.3 8.3 8.3 8.3 8.3 8.2 8.3
0.0 0.0 0.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.2 0.0
Emissions (g km-1) PM
σ
CO2
σ
NOx
σ
CO
σ
0.17 0.41 0.20 0.17 0.25 0.20 0.26 0.29 0.28 0.20 0.32 0.23
0.03 0.15 0.02 0.01 0.01 0.03 0.01 0.01 0.01
1167 2124 1555 1180 1330 1211 1827 1444 1744 1391 1633 1504
64 69 93 60 63 36 61 63 57
11.6 21.3 15.7 11.8 13.9 13.2 22.6 14.7 18.7 15.4 16.6 15.9
0.7 0.7 0.8 0.7 0.3 0.8 1.1 0.8 1.0
5.1 9.3 6.4 6.8 7.0 5.2 10.0 9.3 11.0 7.3 8.6 7.5
0.1 0.0 0.6 0.2 1.2 0.1 0.1 0.2 0.2
PM: particulate matter.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
737
Sheinbaum et al.
Figure 6. EPA-98 results of tests emissions. Table 10. Summary of the repeated measures multivariate ANOVA.
recycling, as well as a programme with full participation of local district governments and producers of biodiesel.
Measure
F
sig.
Acknowledgements
PM NOx CO CO2
0.661 0.236 0.149 1.119
0.466 0.650 0.758 0.326
The authors gratefully acknowledge the support of Ivonne R Soria and Sonia Briceño for their collaboration in this project.
The significance (sig.) shown depicts the Greenhouse-Geisser corrected value. PM: particulate matter.
reduce 349.3 t of CO, 111.1 t of NOx, 50.8 t of PM, and 16,455 t of CO2 per year. Furthermore, this study shows the importance of developing emission tests before applying a biofuel programme. The hypothesis that older buses would be the most suitable targets for biodiesel substitution was demonstrated to be incorrect. They would have incremented local pollutant emissions. The development of a Mexico City programme that collects WCO and transforms it into biodiesel would bring reductions in local pollution, and green-house gas emissions. It would also help to solve the environmental and maintenance problems related to final disposal of large amounts of WCO. In order to increase WCO disposal, it is necessary for the City Government to develop a local standard to increase WCO
Declaration of conflicting interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study project was supported by the Ministry of Science, Technology and Innovation of Mexico City, and it was conducted by a research group at UNAM, with the participation of a private producer of biodiesel and the local government of the Delegación Cuauhtémoc.
References ASTM (2015) ASTM D6751-15. Standard specification for diesel fuel oil, biodiesel blend (B6 to B20). Basha SA, Gopal KR and Jebaraj S (2009) A review on biodiesel production, combustion, emissions and performance. Renewable and Sustainable Energy Reviews 13: 1628–1634. Can Ö (2014) Combustion characteristics, performance and exhaust emissions of a diesel engine fuelled with a waste cooking oil biodiesel mixture. Energy Conversion and Management 87: 676–686.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
738
Waste Management & Research 33(8)
Table 11. Potential biodiesel production in Mexico City (year 2012). VOM
PopM
PopMC
Rr
WCO to BD efficiency
tonne 482,923
millions 117.05
millions 8.91
10%
95%
BDMC
Density of biodiesel from WCO
BDMC
tonne 3,492.3
tonne (m3)-1 0.88
m3 3,968.5
Source: Comision Nacional de Población (2014); Instituto Nacional de Estadística y Geografía (2014); Sheinbaum -Pardo et al. (2013); UNFCCC/ CCNUCC (2008). WCO: waste cooking oil; M: Mexico; MC: Mexico City.
Table 12. Mitigation potential of WCO-biodiesel of local pollutants in Mexico City. Emissions per bus (g km-1)
Total reduction (tonne)
B0
B10
B20
B10
B20
Buses CO NOx PM
6.8 15.7 0.48
1087 4.6 15 0.16
544 6.5 14.4 0.31
174.6 55.5 25.4
11.9 51.6 6.7
Source: Results from Table 7 and Table 11.
Table 13. Mitigation potential per year of WCO-biodiesel of CO2 emissions in Mexico City. Number of buses CO2
Emissions biodiesel from WCO (g L-1)
574.7
Emissions from petrodiesel (g L-1)
2647.6
Mitigation potential B10 B10 (tonne)
B20 (tonne)
1087 16,449
544 16,449
Source: Results from Table 11. Comision Nacional de Población (CONAPO) (2014) Proyecciones de Población. Available at: http://www.conapo.gov.mx (accessed 2 December 2014). Diario Oficial de la Federación (DOF) (1997) NOM-002-SEMARNAT-1996. Norma Oficial Mexicana que establece Límites Máximos de Contaminantes en las Descargas de Aguas Residuales en Aguas y Bienes Nacionales. Available at: http://www.conagua.gob.mx/CONAGUA07/ Noticias/NormasOficialesMexicanas.pdf (accessed 10 June 2015). Diario Oficial de la Federación (DOF) (2006) Norma Oficial Mexicana NOM-086-SEMARNAT-SENER-SCFI-2005: Especificación de los combustibles fósiles para la protección ambiental, México. Available at: http://www.profepa.gob.mx/innovaportal/file/1278/1/nom-086-semarnat-sener-scfi-2005.pdf (accessed 10 June 2015). DGF (2011) Recommendations and findings of the 6th international symposium on deep-frying – errors and myths of industrial and catering frying, Hagen, Germany, 22–24 May 2011. Available at: http://www.dgfett.de/ material/recomm.php (accessed 10 June 2015). DGF (2012) Optimum deep-frying. Recommendations by the German Society for fat science (DGF, Deutsche Gesellschaft für Fettwissenschaft e.V.). Available at: http://www.dgfett.de/material/optimum_frying.pdf (accessed 10 June 2015). Gaceta Oficial del Distrito Federal (GODF) (2003) Ley de Residuos Sólidos del Distrito Federal. Available at: http://www.paot.org.mx/centro/leyes/ df/pdf/2015/LEY_RESIDUOS_SOLIDOS_28_11_2014.pdf (accessed 10 June 2015). Gaceta Oficial del Distrito Federal (GODF) (2012) NADF-015-AGUA-2009. Norma Ambiental para el Distrito Federal que establece los límites máximos permisibles de contaminantes en las descargas de aguas residuales de procesos y servicios al sistema de drenaje y alcantarillado del Distrito Federal, provenientes de las fuentes fijas. Available at: http://www.
sedema.df.gob.mx/sedema/images/archivos/sedema/leyes-reglamentos/ normas/locales/NADF-015-AGUA-2009.pdf (accessed 10 June 2015). Giakoumis EG, Rakopoulos CD, Dimaratos AM, et al. (2012) Exhaust emissions of diesel engines operating under transient conditions with biodiesel fuel blends. Progress in Energy and Combustion Science 38: 691–715. Instituto Nacional de Estadística y Geografía (INEGI) (2010) Agenda estadística del Distrito Federal. Instituto Nacional de Estadística y Geografía (INEGI) (2014) Banco de Información Económica. Available at: http://www.inegi.org.mx/ sistemas/bie/ (accessed 2 December 2014). Kalam MA, Masjuki HH, Jayed MH, et al. (2011) Emission and performance characteristics of an indirect ignition diesel engine fuelled with waste cooking oil. Energy 36: 397–402. Kreso A, Johnson J, Gratz L, et al. (1998) A study of the effects of exhaust gas recirculation on heavy-duty diesel engine emissions. SAE Technical Paper 1998: 981422. DOI: 10.4271/981422. Mandal B, Palit S, Chowdhuri AK, et al. (2011). Environmental impact of using biodiesel as fuel in transportation: a review. International Journal of Global Warming 3: 232–256. Nas B and Berktay A (2007) Energy potential of biodiesel generated from waste cooking oil: An environmental approach. Energy Sources Part B 2: 63–71. Red de Transporte de Pasajeros (2013) Operation report. Internal report. Schneider DR and Ragossnig AM (2013) Biofuels from waste. Waste Management & Research 31: 339–340. Secretaría del Medio Ambiente del Gobierno del Distrito Federal (SMA) (2010a). Inventario de emisiones de gases de efecto invernadero y carbón negro de la ZMVM. Available at: http://www.sma.df.gob.mx/ inventario_emisiones/index.php?op=pub# (accessed 2 December 2014). Secretaría del Medio Ambiente del Gobierno del Distrito Federal (SMA) (2010b) Inventario de emisiones de contaminantes criterio de la ZMVM.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
739
Sheinbaum et al. Available at: http://www.sma.df.gob.mx/inventario_emisiones/index. php?op=pub# (accessed 2 December 2014). Sheinbaum-Pardo C, Calderón-Irazoque A and Ramírez-Suárez M (2013) Potential of biodiesel from waste cooking oil in Mexico. Biomass and Bioenergy 56: 230–238. Stoll U and Gupta H (1997) Management strategies for oil and grease residues. Waste Management & Research 15: 23–32. Talens Peiró L, Méndez GV and Durany XGI (2008) Exergy analysis of integrated waste management in the recovery and recycling of used cooking oils. Environmental Science and Technology 42: 4977e81. United States Environmental Protection Agency (2010) Biodiesel, technical highlights. Office of Transportation and Air Quality EPA-420-F-10–009. United States Environmental Protection Agency (2015) Heavy trucks, buses, and engines. Available at: http://epa.gov/oms/hd-hwy.htm (accessed 6 May 2015). UNFCCC/CCNUCC (2008) Approved baseline and monitoring methodology AM0047. Production of biodiesel based on waste oils and/or waste fats
from biogenic origin for use as fuel. CDM e Executive Board AM0047/ Version 02. Sectoral Scope: 01 and 05 EB33. Verhaeven E, Pelkmans L, Govaerts L, et al. (2005) Results of demonstration and evaluation projects of biodiesel from rapeseed and used frying oil on light and heavy duty vehicles. SAE Technical Paper Series 2005– 01–2201. Wang H and Wang C (2013) Municipal solid waste management in Beijing: characteristics and challenges. Waste Management & Research 31: 67–72. Weaver CS and Balam-Almanza MV (2001) Development of the `RAVEM’ Ride-Along Vehicle Emission Measurement System for Gaseous and Particulate Emissions. SAE Technical Paper Series 2001-01-3644. Weaver CS and Petty LE (2004) Reproducibility and accuracy of on-board emission measurements using the RAVEM™ System. SAE Paper 2004– 01: 0965. Yaakob Z, Mohammad M, Alherbawi M, et al. (2013) Overview of the production of biodiesel from waste cooking oil. Renewable and Sustainable Energy Reviews 18: 184–193.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
research-article2015
WMR0010.1177/0734242X15590471Waste Management & ResearchSheinbaum et al.
Original Article
Biodiesel from waste cooking oil in Mexico City
Waste Management & Research 2015, Vol. 33(8) 730–739 © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0734242X15590471 wmr.sagepub.com
Claudia Sheinbaum1, Marco V Balam2, Guillermo Robles1, Sebastian Lelo de Larrea1 and Roberto Mendoza1
Abstract The aim of this article is to evaluate the potential use of biodiesel produced from waste cooking oil in Mexico City. The study is divided in two main areas: the analysis of a waste cooking oil collection pilot project conducted in food markets of a Mexico City region; and the exhaust emissions performance of biodiesel blends measured in buses of the Mexico City public bus transportation network (RTP). Results from the waste cooking oil collection pilot project show that oil quantities disposed depend upon the type of food served and the operational practices in a cuisine establishment. Food markets’ waste cooking oil disposal rate from fresh oil is around 10%, but with a very high standard deviation. Emission tests were conducted using the Ride-Along-Vehicle-EmissionsMeasuring System in two different types of buses while travelling a regular route. Results shows that the use of biodiesel blends reduces emissions only for buses that have exhaust gas recirculation systems, as analysed by repeated measure analysis of variance. The potential use in Mexico City of waste cooking oil for biodiesel is estimated to cover 2175 buses using a B10 blend. Keywords Biodiesel, waste cooking oil, food markets, emissions, Mexico City
Introduction In general, waste cooking oil (WCO) can be defined as an oilbased substance consisting of edible vegetable matter that has been used in the preparation of foods and is no longer suitable for human consumption (Kalam et al., 2011). Fats and vegetable oils are mixtures of triacylglycerols, composed of fatty acids and glycerol. During the deep-frying cooking process, triacylglycerols are oxidised and polymerised, producing polar compounds like free short-chain fatty acids, mono- and di-glycerides, aldehydes, ketones, polymers, and cyclic and aromatic compounds (DGF, 2012). Some of these degradation products have been linked to different human ailments when ingested (DGF, 2011). For this reason, the deep-fry cooking process generates WCO no longer suitable for consumption. Nevertheless, oil and grease are among the most stable of organic compounds that are not easily decomposed biologically (Stoll and Gupta, 1997). The discharge of WCO into drains or sewers provokes blockages, and if dumped in municipal solid waste landfills or into municipal sewage treatment plants, it creates operational problems along with pollution of water and soil (Talens Peiró et al., 2008). Mexico has federal and local regulations for the fat content of wastewater disposal (Diario Oficial de la Federación, 1997; Gaceta Oficial del Distrito Federal, 2012), however; the enforcement of the regulation is weak. The same case occurs with WCO management plans, considered in the local law of solid wastes (Gaceta Oficial del Distrito Federal, 2003). For this reason it is
important not only to regulate, but also to generate alternatives and incentives for WCO management. There are several options for the collection and treatment of oil and grease residues once they have been discharged into the drain. The most common is the grease trap, which avoids water pollution but maintains the problem of the final disposal. A different approach is to separate WCO at its source and develop collecting systems for recycling. There are several cities in the world that have developed this approach (Schneider and Ragossnig, 2013; Sheinbaum-Pardo et al., 2013; Wang and Wang, 2013). WCO can be used in soap manufacture and oleo chemical industries, and can also be used as the main raw material to produce biodiesel. The simplest process to produce biodiesel from vegetable oil (and methanol) is a base-catalysed transesterification that produces methyl esters and glycerine (Nas and Berktay, 2007). Biodiesel can be blended with diesel and used in many different concentrations, but biodiesel blends higher than B20
1Instituto
de Ingenieria, Universidad Nacional Autónoma de México, Mexico DF, Mexico 2Ambientalis Environmental Consulting, Mexico DF, Mexico Corresponding author: Claudia Sheinbaum, Instituto de Ingenieria, Universidad Nacional Autónoma de México, Ciudad Universitaria, México DF 04510, Mexico. Email: [email protected]
Downloaded from wmr.sagepub.com by guest on November 14, 2015
731
Sheinbaum et al. (20% biodiesel) require special handling and engine modifications (United States Environmental Protection Agency, 2010). One of the main concerns of using biodiesel blends from WCO is the air pollution that can caused by the burning of this fuel. Several authors have studied exhaust engine emissions using biodiesel blends as fuel. Some studies report that biodiesel decreases the tailpipe emissions of particulate matter (PM), carbon monoxide (CO), and volatile organic compounds, yet more controversy has been manifested on nitrogen oxide (NOx) emissions (Basha et al., 2009; Can, 2014; Giakoumis et al., 2012; Kalam et al., 2011; Mandal et al., 2011; Verhaeven et al., 2005; Yaakob et al., 2013). For this reason, any project that considers the use of biodiesel from WCO in a large scale would require a deep analysis, especially if it is going to be developed in urban areas with air quality problems. In this article, we present a case study developed in food markets of a Mexico City region. The study was conducted for several purposes: (a) to evaluate problems and barriers in the development of a WCO collection programme in markets and restaurants of Mexico City; (b) to quantify an average rate of WCO disposal in relation to fresh oil; and (c) to evaluate exhaust engine emissions of biodiesel from WCO blends in Mexico City buses.
Methodology WCO collection The study was conducted in a city area called Delegación Cuauhtémoc. It is one of the 16 political districts of the city. It has 530 thousand inhabitants, but receives more than 3 million people every day. It includes downtown Mexico City where most of the federal and local government offices are based. It produces 4.6% of the national gross domestic product, and it concentrates 36% of urban equipment and 40% of the cultural infrastructure of the city (Instituto Nacional de Estadística y Geografía, 2010). Delegación Cuauhtémoc has 29 food markets that embrace 1505 small restaurants. The WCO collection programme for food markets, which lasted over a year, consisted of four stages: (a) division of work and collection logistics; (b) education and training for restaurant owners and workers; c) collection follow-up and survey application; d) measurement of WCO disposal rate. In the WCO collection campaign included three teams. The first team led by the university was in charge of the programme coordination, education, training, application, and analysis of surveys and measurements. The private producer of biofuel was in charge of WCO collection, and officials of the Cuauhtémoc District were in charge of establishing communication between the university group and the private enterprise, with restaurants owners and market administrators. Education and training for cuisine owners and workers focused on four areas: (a) a general overview of the health effects of over-fried oil; (b) harmful effects of sewer blockages; (c) the use of WCO for biodiesel production; and (d) the procedure to collect and dispose of WCO. The restaurants collected WCO in a
Figure 1. WCO container.
small container that was deposited in a larger market container designed exclusively for WCO (Figure 1). After the first training, two surveys were conducted. The first one was applied in 316 restaurants (out of 1505), which corresponded to a sample of a 95% confidence level and 5% confidence interval. The objectives of these surveys were: (a) find the willingness to participate in the WCO collection programme; and (b) estimate the average amount of fresh oil used per costumer. A second survey was conducted in 127 restaurants that were participating actively in the programme (out of 219), which corresponded to a sample of a 95% confidence level and 5.5% confidence interval. The objective of this survey was to estimate the rate of WCO disposal. Because the results of the second survey had a very high dispersion, a direct measurement of the volume of WCO disposal was carried out in 19 restaurants. Three measurements were developed for each restaurant. The measurements consisted in quantifying the fresh oil that was to be used in 1 week. Additionally, we asked the owner to collect the WCO and store it during the week. The volume of the fresh oil as well as the volume of the WCO was measured every week for three different weeks.
Biodiesel production Biodiesel is produced in a small private plant. The production process started with the recovery of WCO from restaurants and households. Once the WCO was collected, it is filtered in order to separate solids, and then transformed into biodiesel by the transesterification process (Sheinbaum-Pardo et al., 2013). Biodiesel is tested according to the ASTM International standard D6751 (ASTM, 2015).
Emission testing Most research on biodiesel emissions have focused on the comparison between sources of biodiesel and petro-diesel in laboratory settings, in contrast, our measurements were carried out in the most natural settings possible, using a Ride-Along-VehicleEmissions-Measuring (RAVEM) System in a route that simulated the normal conditions of the public transport system (Weaver and Balam-Almanza, 2001).
Downloaded from wmr.sagepub.com by guest on November 14, 2015
732
Waste Management & Research 33(8)
Table 1. RTP buses by technology and model year. Model
2001
2002
2004
2006
2009
EPA-98 EPA-04 EURO-V EURO-IV Total
282
340
103
282
282
340
103
282
250 30 21 301
Note: Although some buses are more than 10 years old, they will continue to be in operation because of lack of funds for bus substitution.
The measurements were developed in September 2013, for two blends, B10 and B20, in buses of the public city-owned transport company called RTP (Red de Transporte de Pasajeros: Passenger Transport Network). CO2, CO, NOx, and PM were measured, but CO2 emissions were also accounted using a different methodology (Sheinbaum-Pardo et al., 2013). With 1308 buses (Table 1), RTP represents about 14% of all diesel passenger urban buses in the city. The average distance travelled by a RTP bus is 200 km per day and the average fuel economy is 2 km L-1 (Red de Transporte de Pasajeros, 2013). Two types of bus technology were measured: EPA-98 and EPA-04. These technologies correspond to the US Federal (EPA) emission standards for heavy-duty diesel truck and bus engines for 1998 and 2004 (United States Environmental Protection Agency, 2015), the latest emission standard required for the bus to have exhaust gas recirculation systems. Emission measurements were carried out using the RideAlong-Vehicle-Emissions-Measuring System (RAVEM), which was designed to maintain proportional sampling during transient variations in engine speed, load, and exhaust flow rate. RAVEM, based on the principle of constant volume sampling (CVS), measures gaseous and particulate exhaust emissions from diesel, and alternative fuel engines while riding along a vehicle. A schematic of RAVEM system can be found in Weaver and BalamAlmanza (2001) and Weaver and Petty (2004). As in all CVS systems, the pollutant concentration in the diluted exhaust leaving the dilution tunnel is proportional to the pollutant mass flowrate in the raw exhaust sample entering the tunnel. Realtime emissions of CO, CO2, and NOx can be thus determined by measuring the concentrations of these pollutants in the dilute exhaust. CO and CO2 concentrations were measured with a California Analytical Instruments (CAI) Model ZRH-2 NDIR analyser; and NOx concentrations were measured with a CAI 400S-HCLD heated chemo-luminescent analyser. For particulate matter measurements (PM), samples of the diluted exhaust and filtered dilution air were taken from the downstream and upstream ends of the dilution tunnel and analysed in laboratory, considering the discount of PM air content (Weaver and Petty, 2004).
Quality assurance The operation procedures include some measures of quality assurance (QA). Two key QA procedures are CO2 recovery and fuel consumption. During the CO2 recovery procedure, CO2 is injected from a pressurised cylinder to the dilution tunnel. At the
end of the procedure, CO2 measures are compared with the changed weight of the cylinder. Fuel consumption QA compares the fuel mass consumed during the tests, with fuel mass calculated from the mass balance of CO and CO2 emissions. Table 2 shows results of QA tests.
Procedure Buses and fuels. Six buses of two different technologies were selected for exhaust emission measurements: three EPA-98 and three EPA-04, all of them in well-maintained operative conditions. All six buses were measured for 100% petro-diesel (B0) as a baseline; and B10 and B20 blends. Three sets of measurements were taken to assure statistical robustness. Diesel was obtained from the RTP station service that buys fuel from the Mexican state-owned company Pemex. According to current fuel standards, diesel sulphur content is 15 ppm (Diario Oficial de la Federación, 2006). Route, weight simulation, and testing procedures. A test cycle was designed to follow a route that simulated the normal conditions of the RTP buses. The test cycle bus route was 8.3 km long, and had 22 bus stops of 10 s each. Overall, it took 45 min to transit. Buses were tested under regular traffic conditions from 8 a.m. to 6 p.m. Water containers weighting 4.5 t were used to simulate a load of 70% of the bus maximum capacity. The same driver drove the buses for every test. All buses were tested three times for all three types of fuel mix (B0, B10, and B20). Once a bus was ready for testing, the measurement equipment was connected and calibrated, and then the filters for PM were inserted. Testing was carried out on the predetermined route for 45 min, if the route was finished before time, the bus would wait in idle until the established time was reached. The bus speed was determined by the contiguous traffic. Once testing was terminated, gas samples were measured and PM filters were removed and sent to the laboratory for analysis. Figures 2 and 3 show pictures of this measurement set up.
Results and discussion WCO collection project The education–training programme was conducted for those interested in the project (it was not mandatory to attend). The programme registered personnel and owners of 452 restaurants of 28 food markets (which represented 41% of the total). After 2 months, and two visits of the team to all participants, only 121 restaurants of 16 markets remained (Table 3), which represented 27% of those who assisted in the education–capacitation programme, and only 8% of the food markets of the area of study. The main reason for the poor participation was the lack of encouragement from the market administration to follow the programme. A first survey to estimate the new edible oil bought per costumer per day, was applied to 316 restaurants. Results are presented in Table 4. A second survey to estimate the WCO rate over new oil was conducted for some the restaurants that participated in the project (121). Results are shown in Figure 4. Because of the dispersion of the sample, extreme numbers were taken out of the final results
Downloaded from wmr.sagepub.com by guest on November 14, 2015
733
Sheinbaum et al. Table 2. QA RAVEM tests. Test
Test type
Fuel estimation (mass balance) (g)
Fuel consumption (measured) (g)
%
MX1113 MX1125 MX1193 MX1194
Fuel recovery Fuel recovery CO2 recovery CO2 recovery
869 378 52 51
870 385 55 50
99 97 95 102
Figure 2. RAVEM on board.
Figure 3. Water containers on board.
(above 35%); Table 5 presents new results. As shown, the standard deviation is nearly the value of the average (9.3% ±8%). For this reason, a direct measurement was conducted. Details are explained in the methodology section. Measurements were taken from 19 restaurants out of four food markets. For each restaurant, three volume measurements were taken (one week each). As shown, measurements were not possible in all the restaurants. Results are surprisingly similar to those of the second survey (Table 6). The rate of WCO from new oil resulted in 10.8% ±9.6%. Results show that oil quantities released or disposed depended upon the type of food served and the operational practices in a cuisine establishment. In the case of food markets in Mexico City, it is between 2% and 20%, with an average of 10%.
Table 3. Participants after 2 months.
RAVEM: Ride-Along-Vehicle-Emissions-Measuring.
Emission tests
Number
Food market
1 2
San Joaquin anexo Tepito 60 (ropa y telas ) Melchor Ocampo Lagunilla zona San Lucas Insurgentes La Dalia San Juan Arcos de Belen Dos de Abril Abelardo l. rodriguez ( zona ) Martinez de la Torre zona Bugambilia Francisco Sarabia Isabel la Catolica San Cosme Pequeño comercio
3 4 5 6 7 8 9 10 11
Emission results for each vehicle are presented as the arithmetic average of all three measurements for each fuel type tested: B0, B10, and B20. Measurements made with B0 served as a baseline to which comparisons of B10 and B20 were made. When test results exceeded 20% for PM and 15% for other pollutants, they were eliminated from averaging. Nevertheless, arithmetic averages contain at least two measurements. The results described below are organised according to the bus engine technology.
EPA-04 Table 7 and Figure 5 show a summary of the emission results of each of the EPA-04 buses tested. Emissions are reported in grams per kilometer for PM, NOx, CO2, and CO, along with an
12 13 14 15 16 Total
Participation of restaurants
% of total
7 5
58 100
33 23 30 11 10 28
76 56 66 84 45 62
16 11
57 30
12
23
10 4 5 6 8 219
62 26 33 10 50 55
Case study developed from February to September 2014.
estimation of fuel consumption. Furthermore an estimation of relative change is also depicted. As shown, all three EPA-04 vehicles reduced 66% of PM emissions when using B10, and 36% when using B20. It is difficult to understand why the lower concentration of biodiesel
Downloaded from wmr.sagepub.com by guest on November 14, 2015
734
Waste Management & Research 33(8)
presents larger reductions, since it was expected that B20, having less sulphur than B10 and B0, would present less particulate formation; however, these results are consistent in all three vehicles. NOx reductions were of 4% and 8% for B10 and B20, respectively, also consistent in all three vehicles. Table 4. New edible oil bought per costumer per day in food markets. Restaurants where survey was applied Average number of costumers per week Average volume of new oil bought per week Average amount of new oil per costumer per week Standard deviation
316 350 13.75 L 0.06 L 0.01 L
Case study developed from February to September 2014.
EPA-98
140%
Table 9 and Figure 6 show a summary of the emission results of each of the EPA-98 buses tested. Emissions are reported in the same manner as the EPA-04 emission results above. As shown, instead of reductions, in the case of EPA-98 buses, measures
120%
WCO/new oil
CO2 emissions (directly related to fuel consumption) were reduced by 6% with the use of B10 and by 5% with the use of B20. This suggests that biodiesel is a very interesting option to explore in the whole vehicle fleet. CO results, although illustrative, are of little impact since diesel vehicles emit very little quantities of this gas. We conducted a repeated measures multivariate analysis of variance (ANOVA) to estimate the extent to which observed changes in emissions were significant. Table 8 summarises these results. As shown, only measurements of NOx and CO presented significant reductions in passenger buses using the EPA-04 technology.
100% 80% 60% 40%
Table 5. Estimation of WCO from new oil based on survey results.
20% 0%
0
20
40
60 80 Restaurants
100
120
140
Figure 4. Results of second survey: WCO rate from new oil. WCO: waste cooking oil.
Valid surveys WCO rate Standard deviation
108 9.3% 8.0%
WCO: waste cooking oil.
Table 6. Volume measurements (WCO out of new oil). Restaurant Measurement 1 New oil (L) WCO (L) Rate 1 9.8 2 7.5 3 34.5 1 24.0 2 7.5 3 4 9.0 1 2 3 4 10.0 5 7.0 6 1 1.8 2 3 4 10.0 5 9.0 6 18.0 Average Standard deviation
0.9 2.4 0 0.9 2.4
Measurement 2
Measurement 3
New oil (L) WCO (L) Rate
New oil (L) WCO (L)
1.0 1.0
0.5
9.1% 10.7 32.0% 3.0 24.0 3.7% 32.0% 12.0 6.0 44.4% 6.0 12.0 5.0 6.0 11.6% 5.0 17.7% 18.0 3.6 27.8% 9.0
0.3 0.5 1.5
7.5 2.5% 13.4 5.6% 8.3% 9.0
4
1.2 1.2
Average Rate
New oil (L) WCO (L) Rate
9.4% 10.8 33.3% 6.0 30.0 21.0 3.7% 7.5
0.9 0.9
8.3% 10.4 15.0% 5.5
0.9 1.4
3.4 0.3
16.1% 15.0 4.0% 9.0
1.4 1.0
2.9 1.9
48.3% 29.8%
7.0 9.2
2.7 1.8
0.4 0.3
6.7% 5.0%
0.1 0.1 0.1
1.9% 1.2% 0.9%
0.7 0.1
18.3% 6.0 13.3% 6.3 28.8% 8.3% 6.0 10.0% 5.0 4.2% 18.0 9.7% 2.7 10.8 11.7 9.3% 0.4% 6.3
0.6
9.5%
1.0
11.1% 12.0
0.2
1.7%
6.0 6.7 21.5 3.2 10.8 11.7 7.5 9.9 9.0 13.0
0.5 0.7 1.0 0.3 0.3 0.1 0.7 0.3 0.5 0.9
0.4 1.1 1.6 1.4 0.5 0.5 0.8 0.4 0.0
WCO: waste cooking oil.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
8.9% 26.1% 9.6% 11.5% 38.1% 19.1% 7.5% 10.0% 4.7% 7.9% 2.8% 0.9% 9.3% 3.4% 5.6% 6.9% 10.8% 9.6%
735
Sheinbaum et al. Table 7. Summary of EPA-04 emission results. Bus–blend
5143–BO 5143–B10 5143–B20 5108–BO 5108–B10 5108–B20 5091–BO 5091–B10 5091–B20 Average B0 Average B10 Average B20
Distance travelled (km)
Emissions (g km-1) PM
σ
CO2
σ
NOx
σ
CO
σ
8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3
0.60 0.19 0.53 0.47 0.17 0.21 0.37 0.13 0.18 0.48 0.16 0.31
0.28 0.03 0.09 0.18 0.01 0.01 0.03 0.03 0.01
1612 1387 1517 1462 1381 1349 1290 1331 1270 1455 1366 1378
133 38 7 41 20 42 50 21 10
15.2 14.0 13.5 16.0 15.4 14.8 15.9 15.6 15.1 15.7 15.0 14.4
1.0 0.2 0.2 0.4 0.4 0.1 0.2 0.1 0.2
9.7 5.9 9.5 5.7 4.4 5.1 5.1 3.4 5.1 6.8 4.6 6.5
0.9 0.5 0.2 0.4 0.5 0.0 0.3 0.1 0.7
Figure 5. EPA-04 results of test emissions.
show increases in PM (59% and 15% on average for B10 and B20, respectively), and marginal increases in NOx (8% and 3% for B10 and B20 blends, respectively). In the case of CO2, there is a 17% increase for B10 and a 3% increase for B20. Again, we conducted a repeated measures multivariate ANOVA to estimate the extent to which observed changes in emissions were significant. Table 10 summarises these results. As shown, no measurements presented significant differences in passenger buses using the EPA-98 technology.
Potential of biodiesel from WCO and related emissions Sheinbaum et al. (2013) estimated WCO production in Mexico, using vegetable oil sales and WCO recovery rate. A gross
estimation for Mexico City WCO availability for biodiesel production can be calculated based on population. Therefore, biodiesel production from WCO for a certain year will be: BD MC = WCOMC *η (1)
and:
WCO MC = VO M / Pop M * Pop MC * Rr (2)
where BDMC is the biodiesel production potential in Mexico City, η is the recovery efficiency of WCO to biodiesel production (in volume), WCOMC is the waste cooking oil available for biodiesel in Mexico City, VOM is the vegetable oil sales in the country, PopM is the country´s population, PopMC is the
Downloaded from wmr.sagepub.com by guest on November 14, 2015
736
Waste Management & Research 33(8)
Mexico City population, and Rr is the recovery ratio of WCO to fresh vegetable oil consumption (from food markets based on this study). Table 11 shows values for equations (1) and (2) for the year 2012. Assuming that all the WCO produced in Mexico City is utilised for biodiesel production, the biodiesel potential from WCO in the City is 7938 m3 based on 2012 data. RTP public buses (SMA, 2010a) circulate an average distance of 73,000 km per year and have an average fuel economy of 2 km L-1. If a B10 blend is used, potentially, 1087 public buses in Mexico City could use biodiesel from a WCO blend. If B20 is used, then potentially 544 buses can use biodiesel from WCO. Considering a recovery ratio (Rr) of 20%, the number of buses is multiplied by 2. The emission reduction potentials are shown in Table 12 and Table 13 only for buses with EPA-04 technologies and beyond. In contrast, the CO, NOx, PM, and CO2 emissions registered in year 2010 from diesel passenger buses in the Mexico City Metropolitan area were: CO: 46,493 t; NOx: 25,311 t; PM10 +PM2.5: 700 t; CO2: 2,159,207 t (Secretaría del Medio Ambiente del Gobierno del Distrito Federal, 2010a, 2010b).
Table 8. Summary of the repeated measures multivariate ANOVA. Measure
F
sig.
PM NOx CO CO2
2.197 4.800 4.632 0.10
0.176 0.044 0.029 0.960
The significance (sig.) shown depicts the Greenhouse–Geisser corrected value. PM: particulate matter.
Conclusions and recommendations This article presents the outcomes of a pilot project of WCO collection developed in food markets from an area of Mexico City. It also presents the results of exhaust emissions performance of biodiesel blends measured in buses of the City’s public bus transportation network (RTP). Based on these results, an estimation of WCO availability for biodiesel production in Mexico City was estimated. Results from the WCO collection pilot project show that oil quantities released or disposed depend upon the type of food served and the operational practices in a cuisine establishment. A disposal rate of WCO from fresh oil was 10.8%, with a standard deviation of 9.6%. In order to achieve more participation of restaurant owners, an increased participation of market and governmental authorities is recommended. Results show that biodiesel blends from WCO should not be used for buses with technologies EPA-98 and earlier, because emissions of PM and NOx might increase. Design differences between EPA-98 and EPA-04 engines could explain these results. In contrast to an EPA-98 engine, an EPA-04 engine counts with an exhaust gas recirculation system. This system was originally designed to reduce NOx emissions. In engines with this system, the exhaust gas is cooled and recycled into the motor to dilute the air/fuel mix, and thus, the quantity of oxygen entering the combustion chamber. This has an effect of temperature reduction in the chamber, which consequently reduces the formation of NOx (Kreso et al., 1998). For technologies that use exhaust gas recirculation systems, such as the EPA-04 buses, the best blend for CO reductions was B10 and for NOx reductions was B20. Results were analysed by a repeated measures multivariate ANOVA to estimate the extent to which observed changes in emissions were significant The potential use in Mexico City of WCO for biodiesel is estimated to cover 2175 buses using a B10 blend. This would
Table 9. Summary of EPA-98 emission results (results from field tests). Bus-blend
1115-BO 1115-B10 1115-B20 1367-BO 1367-B10 1367-B20 1127-BO 1127-B10 1127-B20 Average B20 Average B10 Average B20
Distance travelled (km)
σ
8.3 8.3 8.3 8.3 8.0 8.3 8.3 8.3 8.3 8.3 8.2 8.3
0.0 0.0 0.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.2 0.0
Emissions (g km-1) PM
σ
CO2
σ
NOx
σ
CO
σ
0.17 0.41 0.20 0.17 0.25 0.20 0.26 0.29 0.28 0.20 0.32 0.23
0.03 0.15 0.02 0.01 0.01 0.03 0.01 0.01 0.01
1167 2124 1555 1180 1330 1211 1827 1444 1744 1391 1633 1504
64 69 93 60 63 36 61 63 57
11.6 21.3 15.7 11.8 13.9 13.2 22.6 14.7 18.7 15.4 16.6 15.9
0.7 0.7 0.8 0.7 0.3 0.8 1.1 0.8 1.0
5.1 9.3 6.4 6.8 7.0 5.2 10.0 9.3 11.0 7.3 8.6 7.5
0.1 0.0 0.6 0.2 1.2 0.1 0.1 0.2 0.2
PM: particulate matter.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
737
Sheinbaum et al.
Figure 6. EPA-98 results of tests emissions. Table 10. Summary of the repeated measures multivariate ANOVA.
recycling, as well as a programme with full participation of local district governments and producers of biodiesel.
Measure
F
sig.
Acknowledgements
PM NOx CO CO2
0.661 0.236 0.149 1.119
0.466 0.650 0.758 0.326
The authors gratefully acknowledge the support of Ivonne R Soria and Sonia Briceño for their collaboration in this project.
The significance (sig.) shown depicts the Greenhouse-Geisser corrected value. PM: particulate matter.
reduce 349.3 t of CO, 111.1 t of NOx, 50.8 t of PM, and 16,455 t of CO2 per year. Furthermore, this study shows the importance of developing emission tests before applying a biofuel programme. The hypothesis that older buses would be the most suitable targets for biodiesel substitution was demonstrated to be incorrect. They would have incremented local pollutant emissions. The development of a Mexico City programme that collects WCO and transforms it into biodiesel would bring reductions in local pollution, and green-house gas emissions. It would also help to solve the environmental and maintenance problems related to final disposal of large amounts of WCO. In order to increase WCO disposal, it is necessary for the City Government to develop a local standard to increase WCO
Declaration of conflicting interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study project was supported by the Ministry of Science, Technology and Innovation of Mexico City, and it was conducted by a research group at UNAM, with the participation of a private producer of biodiesel and the local government of the Delegación Cuauhtémoc.
References ASTM (2015) ASTM D6751-15. Standard specification for diesel fuel oil, biodiesel blend (B6 to B20). Basha SA, Gopal KR and Jebaraj S (2009) A review on biodiesel production, combustion, emissions and performance. Renewable and Sustainable Energy Reviews 13: 1628–1634. Can Ö (2014) Combustion characteristics, performance and exhaust emissions of a diesel engine fuelled with a waste cooking oil biodiesel mixture. Energy Conversion and Management 87: 676–686.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
738
Waste Management & Research 33(8)
Table 11. Potential biodiesel production in Mexico City (year 2012). VOM
PopM
PopMC
Rr
WCO to BD efficiency
tonne 482,923
millions 117.05
millions 8.91
10%
95%
BDMC
Density of biodiesel from WCO
BDMC
tonne 3,492.3
tonne (m3)-1 0.88
m3 3,968.5
Source: Comision Nacional de Población (2014); Instituto Nacional de Estadística y Geografía (2014); Sheinbaum -Pardo et al. (2013); UNFCCC/ CCNUCC (2008). WCO: waste cooking oil; M: Mexico; MC: Mexico City.
Table 12. Mitigation potential of WCO-biodiesel of local pollutants in Mexico City. Emissions per bus (g km-1)
Total reduction (tonne)
B0
B10
B20
B10
B20
Buses CO NOx PM
6.8 15.7 0.48
1087 4.6 15 0.16
544 6.5 14.4 0.31
174.6 55.5 25.4
11.9 51.6 6.7
Source: Results from Table 7 and Table 11.
Table 13. Mitigation potential per year of WCO-biodiesel of CO2 emissions in Mexico City. Number of buses CO2
Emissions biodiesel from WCO (g L-1)
574.7
Emissions from petrodiesel (g L-1)
2647.6
Mitigation potential B10 B10 (tonne)
B20 (tonne)
1087 16,449
544 16,449
Source: Results from Table 11. Comision Nacional de Población (CONAPO) (2014) Proyecciones de Población. Available at: http://www.conapo.gov.mx (accessed 2 December 2014). Diario Oficial de la Federación (DOF) (1997) NOM-002-SEMARNAT-1996. Norma Oficial Mexicana que establece Límites Máximos de Contaminantes en las Descargas de Aguas Residuales en Aguas y Bienes Nacionales. Available at: http://www.conagua.gob.mx/CONAGUA07/ Noticias/NormasOficialesMexicanas.pdf (accessed 10 June 2015). Diario Oficial de la Federación (DOF) (2006) Norma Oficial Mexicana NOM-086-SEMARNAT-SENER-SCFI-2005: Especificación de los combustibles fósiles para la protección ambiental, México. Available at: http://www.profepa.gob.mx/innovaportal/file/1278/1/nom-086-semarnat-sener-scfi-2005.pdf (accessed 10 June 2015). DGF (2011) Recommendations and findings of the 6th international symposium on deep-frying – errors and myths of industrial and catering frying, Hagen, Germany, 22–24 May 2011. Available at: http://www.dgfett.de/ material/recomm.php (accessed 10 June 2015). DGF (2012) Optimum deep-frying. Recommendations by the German Society for fat science (DGF, Deutsche Gesellschaft für Fettwissenschaft e.V.). Available at: http://www.dgfett.de/material/optimum_frying.pdf (accessed 10 June 2015). Gaceta Oficial del Distrito Federal (GODF) (2003) Ley de Residuos Sólidos del Distrito Federal. Available at: http://www.paot.org.mx/centro/leyes/ df/pdf/2015/LEY_RESIDUOS_SOLIDOS_28_11_2014.pdf (accessed 10 June 2015). Gaceta Oficial del Distrito Federal (GODF) (2012) NADF-015-AGUA-2009. Norma Ambiental para el Distrito Federal que establece los límites máximos permisibles de contaminantes en las descargas de aguas residuales de procesos y servicios al sistema de drenaje y alcantarillado del Distrito Federal, provenientes de las fuentes fijas. Available at: http://www.
sedema.df.gob.mx/sedema/images/archivos/sedema/leyes-reglamentos/ normas/locales/NADF-015-AGUA-2009.pdf (accessed 10 June 2015). Giakoumis EG, Rakopoulos CD, Dimaratos AM, et al. (2012) Exhaust emissions of diesel engines operating under transient conditions with biodiesel fuel blends. Progress in Energy and Combustion Science 38: 691–715. Instituto Nacional de Estadística y Geografía (INEGI) (2010) Agenda estadística del Distrito Federal. Instituto Nacional de Estadística y Geografía (INEGI) (2014) Banco de Información Económica. Available at: http://www.inegi.org.mx/ sistemas/bie/ (accessed 2 December 2014). Kalam MA, Masjuki HH, Jayed MH, et al. (2011) Emission and performance characteristics of an indirect ignition diesel engine fuelled with waste cooking oil. Energy 36: 397–402. Kreso A, Johnson J, Gratz L, et al. (1998) A study of the effects of exhaust gas recirculation on heavy-duty diesel engine emissions. SAE Technical Paper 1998: 981422. DOI: 10.4271/981422. Mandal B, Palit S, Chowdhuri AK, et al. (2011). Environmental impact of using biodiesel as fuel in transportation: a review. International Journal of Global Warming 3: 232–256. Nas B and Berktay A (2007) Energy potential of biodiesel generated from waste cooking oil: An environmental approach. Energy Sources Part B 2: 63–71. Red de Transporte de Pasajeros (2013) Operation report. Internal report. Schneider DR and Ragossnig AM (2013) Biofuels from waste. Waste Management & Research 31: 339–340. Secretaría del Medio Ambiente del Gobierno del Distrito Federal (SMA) (2010a). Inventario de emisiones de gases de efecto invernadero y carbón negro de la ZMVM. Available at: http://www.sma.df.gob.mx/ inventario_emisiones/index.php?op=pub# (accessed 2 December 2014). Secretaría del Medio Ambiente del Gobierno del Distrito Federal (SMA) (2010b) Inventario de emisiones de contaminantes criterio de la ZMVM.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
739
Sheinbaum et al. Available at: http://www.sma.df.gob.mx/inventario_emisiones/index. php?op=pub# (accessed 2 December 2014). Sheinbaum-Pardo C, Calderón-Irazoque A and Ramírez-Suárez M (2013) Potential of biodiesel from waste cooking oil in Mexico. Biomass and Bioenergy 56: 230–238. Stoll U and Gupta H (1997) Management strategies for oil and grease residues. Waste Management & Research 15: 23–32. Talens Peiró L, Méndez GV and Durany XGI (2008) Exergy analysis of integrated waste management in the recovery and recycling of used cooking oils. Environmental Science and Technology 42: 4977e81. United States Environmental Protection Agency (2010) Biodiesel, technical highlights. Office of Transportation and Air Quality EPA-420-F-10–009. United States Environmental Protection Agency (2015) Heavy trucks, buses, and engines. Available at: http://epa.gov/oms/hd-hwy.htm (accessed 6 May 2015). UNFCCC/CCNUCC (2008) Approved baseline and monitoring methodology AM0047. Production of biodiesel based on waste oils and/or waste fats
from biogenic origin for use as fuel. CDM e Executive Board AM0047/ Version 02. Sectoral Scope: 01 and 05 EB33. Verhaeven E, Pelkmans L, Govaerts L, et al. (2005) Results of demonstration and evaluation projects of biodiesel from rapeseed and used frying oil on light and heavy duty vehicles. SAE Technical Paper Series 2005– 01–2201. Wang H and Wang C (2013) Municipal solid waste management in Beijing: characteristics and challenges. Waste Management & Research 31: 67–72. Weaver CS and Balam-Almanza MV (2001) Development of the `RAVEM’ Ride-Along Vehicle Emission Measurement System for Gaseous and Particulate Emissions. SAE Technical Paper Series 2001-01-3644. Weaver CS and Petty LE (2004) Reproducibility and accuracy of on-board emission measurements using the RAVEM™ System. SAE Paper 2004– 01: 0965. Yaakob Z, Mohammad M, Alherbawi M, et al. (2013) Overview of the production of biodiesel from waste cooking oil. Renewable and Sustainable Energy Reviews 18: 184–193.
Downloaded from wmr.sagepub.com by guest on November 14, 2015
