A New Approach Method of CH4 Emission Estimation from Landfills Municipal Solid Waste (MSW)

The CH4 is one of the six Greenhouse Effect Gases (GEG) that is mentioned in the Kyoto Protocol. The GEG is generated by the anthropic activities which are conducive to climate changes if their management is not conducted in a proper way. The main purpose of the environment policy is the reduction of the GEG emission. It is well-known that the CH4 gas emission from municipal solid waste MSW landfills is responsible for 4 ÷ 5% of the total Greenhouse Effect. It is necessary to have a practical method to calculate the quantitative CH4 gas emission, in order to apply an efficient management of the CH4 gas emission from MSW landfills, conforming or non-conforming. This method has to be transparent, credible, coherent, and applicable both for conforming and non-conforming MSW deposits. This paper proposes a new estimation calculation method of the CH4 gas emission from all MSW deposits in Romania. The IPCC group of experts has made recommendations related to the estimation of CH4 but the European Union (EU) admits that the environmental conditions are not the same in every Member State. The annual evolution of CO2 for the CH4 gas emission at every MSW location is valuable information for the Environment Authority with a view to realistic environmental planning and for an efficient policy to be applied in order to reduce the greenhouse effect of MSW landfills.

called PRTR Protocol or Kiev Protocol) [2] together with the UN Convention on climate changes. This Convention is referring, among others, to the landfills having a daily activity of more than 10,000 tons/day MSW which amounts to more than 450,000 tons/year. For these MSW landfills, starting with 2007, the individual CH 4 emission rate [3] has to be calculated and the results have to be communicated to the public. EU has adopted the European Emission Register in order to be in conformity with the PRTR Protocol. This Register provides some criteria to be fulfilled: transparency, coherence, the possibility to compare results. These criteria are a condition for the calculated results to be accepted into a national data base. Romania has adopted the UN PRTR Protocol and for the MSW landfills with more than 10,000 tons/day, the CH 4 emission will be included in a register. The Member State governments have to report all aspects related to the Climate Changes [3] to an inter-governmental group. It is very clear that a method to estimate the CH 4 methane gas emission from MSW landfills is absolutely necessary [3].
This method has to cover the calculation of the CH 4 emission from both conforming and non-conforming MSW Romanian landfills [4] [5]. This method was applied for the CH 4 emission calculation of 13 MSW landfills-conforming and non-conforming. In this paper the calculated values for CH 4 emission [4] [5] [6] and the equivalent CO 2 for 1 non-conforming and for 2 conforming landfills are presented. Analyzed landfills are located in Satu Mare, Ilfov and Bucharest municipality, Romania. The proposed method has a high degree of efficiency.
The CH 4 emission calculus for those 13 Municipal landfills (msw) and the drawing up adjacent graphics related to the equivalent of CO 2 demonstrate that the GEG is present. The Romanian Environmental Authorities have to act on this matter and to acknowledge about the GEG intensity and its duration [7], in the same time.
The Proposed method allows us the quantitative evaluation of CH 4 emission to be used as a natural energy source. Within the actual management of wastes only the sort of wastes having economical energy value is applied, according to the Europe Council provisions. It is to be mentioned also that only 20% of the generated wastes is sorted. In the deposit body, they are not included: metallic wastes, plastics, tires, recyclable wood or with energetic value, paper wastes and recyclable cartoon. It is to be mentioned also that, from information delivered by the local source, within the landfill body they are not included: inert wastes (construction and demolition), plastics, soils and stones, asbestos; the total contents of these wastes are not considered to be more than 10%.
I have to make a remark: the drawing up graphics were obtained by manual calculation rather than using specific software. ated by the agriculture and live-stock farm activities, e.g. animal and bird dejections. The bio-degradable wastes (rubbish) generated by intensive agriculture have to be taken into consideration as well.
The problem of the global warming and the obligation to apply the Kyoto Convention requirements involve the fulfillment of the rules regarding the limitation of the MSW gas emission [7] and the prohibition to have MSW landfills which do not comply with the rules of environmental protection [2].

Estimative Methods for Ch4 Gas Emission Calculation
The quantity of the CH 4 gas emission from MSW landfills can be estimated, by calculus applying two methods, as follows: This method supposes that a non-dangerous MSW deposit will generate [9] [10], within a year, a certain quantity of CH 4 and, in the next year, it will be a new amount of CH 4 This method will not take into consideration the hypothesis that an MSW deposit is a conglomerate mixed wastes one (see Table 1). Another factor to be taken into consideration is the time-the basic factor for GES emission [10]. Different MSW components are gradually, deteriorated in time, so CH 4 and CO 2 as well as the non-methane gases, and are generated.
In order to illustrate results due to the method 1 use, the conform MSW calculus equations regarding CH 4 emission [10] [11] will be indicated, as follows.
These calculus equations are: where: • L 0 -CH 4 generated potential ( ) g g G C G MSW which depends by the MSW morphological composition it will be calculated by using the following relation, [7] [11]; • R-CH 4 recovered at the inventory year of ( ) g g G C G MSW , the recommended value, supposing that CH 4 is burned and not collected; if not, the recovered quantity of CH 4 calculated by using this method will be reduced from the CH 4 generated quantity.
• 0X-oxide factor having a fractionary values-0 for non-conforming deposits and 0.1 for the well arrangements (conforming) deposits.
CH 4 generated potential, where: • MCF-CH 4 correction factor, whose values are dependent by the location and the management of MSW; • DOC f -the DOC dissimilated fraction-0.55 having values within the interval 0.5 ÷ 0.6; • F-CH 4 fraction part-from deposit gas (LFG) [5], given value is 0.5; It is supposed that a MSW landfill will generate, within a year, a certain amount of CH 4 gas emission which can be estimated [10]. This method doesn't take into consideration the hypothesis that a MSW landfill is a mixed conglomerate of wastes (rubbish).
Another factor to be considered is the time which is the basic factor for CH 4 gas emission [10]. Different components of the MSW landfill are, gradually, degraded in time, and CH 4 , other gases are produced [6].  [17] do not solve the problem of the composition of the waste (rubbish) from MSW. The use of waste statistics assumes that the waste (rubbish) should be analyzed by means of a representative sample of economic operators and human agglomeration [12]. Taking into consideration that every district of Romania has approx. 200 economic operators and urban agglomeration we shall have approximately 8400 economic operators, in total [9].
Approximately 500,000 economic operators are assumed to be in the country which means that statistics representation will cover only 1.6% of the total country economic operators. This fact is quite unacceptable.

DESCRIPTION OF"DANILA VIERU METHOD FOR CONFORMING AND NON-CONFORMING MSW LANDFILLS CH 4 GAS EMISSION ESTIMATION IN ROMANIA, BY CALCULUS"
The method: "Danila Vieru method for conforming and non-conforming MSW landfills CH 4 gas emission estimation, in Romania, by calculus", makes use of the following formula: lved. % 16 12 , CH year This formula (equation) has some advantages, e.g.: 1) The hierarchy [6] of degraded MSW, IN TIME, under the environmental factors [atmospheric precipitations, annual average temperature, alternating periods of rain and drought, freezing and non-freezing periods, the degree of MSW compression, the thickness of waste (rubbish) layers, etc. [13]; 2) The use of time periods for the degradation of MSW; 3) The use of IPCC recommendation related to the application of the methodology calculation formula of CH 4 gas emission from MSW landfills; 4) Taking into consideration the specific environmental conditions of every district of Romania; 5) The specific economic conditions of every district, such as: industrial development, hand-made production, various branches of agriculture, etc. are taken into consideration; It is well-known that CH 4 methane is a specific gas, and its contribution (percentage) to global warming is about 4 ÷ 5% so that the need for the quantification of CH 4 gas emission is imperative. In the meantime, measures to reduce the contribution of the CH 4 gas emission from MSW landfills have to be taken into account.
In July 16, 2009, due to the presence of non-conforming MSW landfills in Romania, some of them are closed while others will be in transition periods, in the case of MSW landfills, the emission of CH 4 methane gas will continue even after the closing period of non-conforming MSW landfills until approximately the year 2017. Before wastes (rubbish) are deposited within the body of MSW and a rational sorting have to be are done.
After the closure of MSW landfills, the quantity of the CH 4 gas emission will decrease but still will continues to exist [14]. Following the legal conditions for opening a new MSW landfill it is absolutely necessary to know the evolution of CO 2 (in equivalent), the location of the new MSW landfill and the potential impact over the environment. As it is known, in approximately 10 years, the warming effect will be intensified due to the collection of the gas MSW landfill.
In my opinion, the above mentioned remarks should be taken into consideration when a CH 4 methane gas emission calculus formula is applied, for the entirely territory of Romania.

Example of Calculus, Methodology-The Assessment
Basic consideration: a) The percentage composition of MSW landfill body is in accordance with the data provisions given in Table 1. b) The wastes (rubbish) from the MSW landfill body are gradually degraded in accordance with the environment conditions; c) To calculate the quantity of CH 4 gas emission from degraded MSW, at the year of calculation, the IPCC recommended values [9] have been taken into consideration.
d) The MSW degraded quantity has the same percentage composition as the MSW landfill body; e) The MSW degraded quantity generates DOC-Dissolved Organic Carbon, and, as a consequence, the CH 4 gas emission is produced.
f) The MSW degraded quantity calculated, in the year T, is given by the expression: Q mswdegrad.T Within Table 1 the waste composition, as% from total, was established following information delivered by: • • Information delivered by the MSW landfills administrators related to the collection area, quantities and type of wastes included in MSW.  Bihor county. It is to be mentioned that the Waste composition, as a conglomerate landfill, is subjected to the environment factors, and as a consequence, the LFG gas (mainly, CH 4 ) is generated, covering the total lifetime of the deposit.

The Evaluation of Qmswdegrad.T in the T Year of Calculation
To determine the MSW degraded quantity, in the first year of emission, the following formula has been used: After the first year, the calculation formula became: where: x x − + = − , [15]. The deposit How to drawing up the Nomograme [15] of the MSW deposit will be explained in another paper.
• T-represent the year of calculation not the current calendar year. A certain MSW deposited quantity remains undegraded every year [8] [12]. This quantity will be taken into consideration in the next year as the Q mswundegrad.T .
This quantity can be estimated by using the formula: The calculus can be done in this way: • Empirical [16] by using the formula: 0.014 T + 0.28, where T-is the annual average temperature, in C 0 , in the district where MSW is located.
If we take into consideration the Romanian districts climate zone conditions the recommended values (as percentage) are to be: 43%, 45%, 50%, 55% and 60%.  Figure 1 and Figure 2.
The evolution of the equivalent CO 2 for a non-conforming MSW landfill is presented in Figure 3. It is to be observed that the CH 4 gas emission continues, after the closing date-the year 2010, as shown.
Wastes deposited quantities (msw) within deposit body are shown in Table 3. These quantities, due to "m" values, according to the Nomograme [15], generated CH 4 quantities as presented within Figure 1, with the following signi-D. Vieru    [15]: in the year 2011 there were collected 7.5 million cubic meters of CH 4 which have been used for green energy production.
For the period 2000 to 2011, the percentage (%) of MSW composition has been considered, as shown in Table 1. Plastic wastes, inert waste, construction and demolition have not to be taken into consideration because they will not affect the CH 4 gas emission [8] [14].
The data were confirmed by collection data.

A Case Study
Within 2000 ÷ 2011 period (see Figure 1) quantities belonging to the interval 250 ÷ 400 Gg, there were deposited, annually. The GEG Effect has been intensified has been intensified, so that in the year of 2011 and a quantity of 7.5 million cubic meters of CH 4 has been used for electric energy production. As a direct consequence the GEG Effect decreased considerably, see Figure 1.
At the starting year of 4 CH emission within the Equation (2) can be used the expression: [3] where m represents the number of months in which maximum 45% of deposited MSW are degradeted, 7 12 m ≤ ≤ [3]. It is to be observed that the CH 4 gas emission increased gradually, but not suddenly, in accordance with the environmental condition of the landfill location [6]. A certain wastes (rubbish) quantity of MSW landfill will remain undegraded and will be taken into consideration in the next year, so the process of MSW It is to be observed that the CH 4 gas emission increased gradually, but not suddenly, in accordance with the environmental condition of the landfill location [6]. A certain waste (rubbish) quantity of MSW landfill will remain un-degraded and will be taken into consideration in the next year, so the process of MSW degraded will generate again DOC, and, as a consequence, CH 4 [6]. A certain waste (rubbish) quantity of MSW landfill will remain undegraded and will be taken into consideration in the next year, so the process of MSW degraded will generate again DOC. The sludge from MSW can be taken into consideration, separately or may be incorporated within bio-degraded waste (rubbish).

Conclusions
This article doesn't comment on the present calculation model but rather draws the attention to a more adapted to the real conditions estimation, by calculus, of the CH 4 gas emission from the actual MSW landfills in Romania, which have to be estimated by the end of 2017. Even if deposited MSW quantities were up to 30 (Gg), in the beginning of 1979 and reached 90 (Gg) in 2010, the evolution of CO 2 exists and has to be known by the Romanian authorities. It is considered that this estimation has to be determined up to the life-end of the considered landfill. As an example, at the existing MSW landfill, in the Satu Mare County, the evolution of the equivalent CO 2 for a period of 42 years up to 2010 when it was closed is presented. The authorities have to inform the public about the evolution of the equivalent CO 2 for existing MSW landfill and also for the location of the new MSW landfills. On the other hand, for the non-hazardous MSW landfills having a capacity between 350 450 ÷ [Gg] it was observed that the top management of this MSW landfills issued estimated quantities of CH 4 gas at unrealistic values, sometimes more than two times lower with respect to the real one, estimated by usual calculation models.
To reduce the greenhouse effect, the evolution of the equivalent CO 2 for the existing MSW landfills in Romania has to be estimated in such a way as to be useful for an applicable environmental planning in accordance with the government's and the European policy in the field of environmental protection. Other gas emissions such as: NON-METHANE ORGANIC COMPOUNDS, 2 NO , NO x , Polycyclic aromatic hydrocarbons , HFC , PFC have not been taken into consideration.
The real estimation of the CH 4 emission quantity from MSW landfills, in Romania, will contribute to a better environmental planning and a better understanding of the contribution that different gases have on the general warming effect and climate changes greenhouse effect.
Finally, it is to be noted that the calculation of the CH 4 emission quantity, by using the Danila Vieru's Method, ( ) 1 Formula , will help Romanian environmental authorities to implement the legal and right decisions regarding the adequate moment when the collected 4 CH emission can be burned, and thus be used in an economical manner.
The proposed method could be applied for the CH 4 emission calculation at MSW landfills quantities between 100 ÷ 200 (Gg/y) e.g. the Satu Mare nonconforming MSW landfill (see Figure 3).
This method which was verified for Romanian landfills could be easily adapted for other countries too, paving the way for a real estimation of the methane gas emission, as real as possible.
The proposed method can be applied either to the MSW landfills which respect legal providing and those (MSW) which not respect such provisions. The quantitative CH 4 estimation is beneficial for the Environmental Authorities but also for the potential investors interested in the CH 4 management. It is to be noted that potential investors have to know the emission quantity and its duration. After MSW depositing is over, it is absolutely necessary to the time-duration when the emission is stopped. In the same time, after the CH 4 emission is over, the resulted compost should be of interest for the farmers.