Levels of Polycyclic Aromatic Hydrocarbons (PAHs) in Healthcare Waste Incinerators’ Bottom Ash from Five County Hospitals in Kenya

Health-care waste contains potentially harmful microorganisms and compounds which can infect and affect hospital patients, healthcare workers, the general public and environment. Therefore, management of health care waste requires safe handling, treatment and disposal procedures. While incineration reduces the volume and quantity of waste for final disposal, it leads to the production of fly and bottom ashes laden with toxic incomplete combustion products such as Polycyclic Aromatic Hydrocarbons (PAHs), dioxins, furans and heavy metals. This exposes workers who handle and dispose the bottom ashes, hospital patients, the general public and environment. The goal of this study was to determine the total and individual levels of 16 most prevalent and toxic PAHs. Bottom ash samples were collected from incinerators in five county hospitals in Kenya, namely;Moi-Voi, Narok, Kitale, Makindu and Isiolo. Bottom ash samples were collected over a period of six months from the five hospitals. The samples were then sieved, homogenised and stored at 4°C in amber coloured glass containers. The PAHs were extracted using 30 ml of a hexane-acetone solvent (1:1) mixture by ultrasonication at room temperature (23°C) for 45 minutes. The PAHs were then analyzed with a GC-MS spectrophotometer model (Shimadzu GCMS-QP2010 SE) connected to a computer work station was used for the PAHs analysis. The GC-MS was equipped with an SGE BPX5 GC capillary column (30 m × 0.25 mm × 0.25 μm) for the separation of compounds. Helium was used as the carrier gas at a flow rate of 15.5 ml/minute and 14.5 psi. 1 μl of the sample was injected at 280°C, split mode (10:1). The oven programming was set for a total runtime of 40 minutes, which included: 100°C (2-minute hold);10°C /min rise to 200°C;7°C /min rise to 249°C;3°C /min rise to 300°C (2-minute hold). The interface temperature was set at 290°C. Analysis was done in Selected Ion Monitoring (SIM) mode and the peak areas of each of the PAHs were collected from the chromatograph and used for quantification of the 16 PAHs listed by the U.S. Environmental Protection Agency (EPA) which included, BaA (benz[a]anthracene: 4 rings), BaP (benzo[a]pyrene: 5 rings), BbF (benzo [b]fluoranthene: 5 rings), BkF (benzo[k]fluoranthene: 5 rings), Chr (chrysene: 4 rings), DbA (dibenz[a,h]anthracene: 5 rings), InP (indeno[1,2,3 - cd] pyrene: 6 rings) and Acp (acenaphthene: 3 rings), Acpy (acenaphthylene: 3 rings), Ant (anthracene: 3 rings), BghiP (benzo[g,h,i]perylene: 6 rings), Flu (fluorene: 3 rings), FluA (fluoranthene: 4 rings), Nap (naphthalene: 2 rings), PhA (phenanthrene: 3 rings) and Pyr (pyrene: 4 rings). Ion source-interface temperature was set at 200°C - 250°C. Internal standards from Sigma Aldrich were used in the analysis and the acquired mass spectra data were then matched against the NIST 2014 library [1] [2]. The mean PAHs concentration in the bottom ashes of each hospital varied broadly from 0.001 mg/kg to 0.4845 mg/kg, and the mean total concentration levels of individual PAHs ranged from 0.0072 mg/kg to 1.171 mg/kg. Low molecular weight PAHs (Phenanthrene, Naphthalene and Fluorene) were predominant in all the hospital wastes whereas Kitale and Narok presented the lowest PAHs concentrations and the lowest number of individual PAHs. Moi/Voi recorded the highest total PAHs concentration at 1.3129 ± 0.0023 mg/kg from a total of 11 PAHs being detected from the bottom ash samples. Narok had only three PAHs being detected at very low concentrations of 0.0041 ± 0.00 mg/kg, 0.0076 ± 0.00 mg/kg and 0.012 ± 0.00 mg/kg for phenanthrene, anthracene and chrysene respectively. This study presents hospital incinerator bottom ash as containing detectable levels of both carcinogenic and non-carcinogenic PAHs. Continued unprotected exposure of hospital workers (waste handlers) to the bottom ash PAHs could be hazardous to their health because of their cumulative effect. Preventive measures e.g. the use of Personal protective equipment (PPE) should be prioritised to minimise direct contact with the bottom ash. The study recommends an upgrade on incinerator technology for efficient combustion processes thus for better pollution control.

Concentration of Copper, Zinc, Lead, Cadmium, and Nickel in the Incinerator Bottom Ash in Five County Hospitals in Kenya

Healthcare wastes contain potentially harmful microorganisms, inorganic and organic compounds that pose a risk to human health and the environment. Incineration is a common method employed in healthcare waste management to reduce volume, quantity, toxicity as well as elimination of microorganisms. However, some of the substances remain unchanged during incineration and become part of bottom ash, such as heavy metals and persistent organic pollutants. Monitoring of pollution by heavy metals is important since their concentrations in the environment affect public health. The goal of this study was to determine the levels of Copper (Cu), Zinc (Zn) Lead (Pb), Cadmium (Cd) and Nickel (Ni) in the incinerator bottom ash in five selected County hospitals in Kenya. Bottom ash samples were collected over a period of six months. Sample preparation and treatment were done using standard methods. Analysis of the heavy metals were done using atomic absorption spectrophotometer, model AA-6200. One-Way Analysis of Variance (ANOVA) was performed to determine whether there were significant differences on the mean levels of Cu, Zn, Pd, Cd and Ni in incinerator bottom ash from the five sampling locations. A post-hoc Tukey’s Test (HSD) was used to determine if there were significant differences between and within samples. The significant differences were accepted at p ≤ 0.05. To standardize the results, overall mean of each metal from each site was calculated. The metal mean concentration values were compared with existing permissible levels set by the WHO. The concentrations (mg/kg) were in the range of 102.27 - 192.53 for Cu, Zn (131.68 - 2840.85), Pb (41.06 - 303.96), Cd (1.92 - 20.49) whereas Ni was (13.83 - 38.27) with a mean of 150.76 ± 77.88 for Copper, 131.66 ± 1598.95 for Zinc, 234.60 ± 262.76 for Lead, 12.256 ± 10.86 for Cadmium and 29.45 ± 18.24 for Nickel across the five sampling locations. There were significant differences between levels determined by one-way ANOVA of Zn (F (4, 25) = 6.893, p = 0.001, p ≤ 0.05) and Cd (F (4, 25) = 5.641, p = 0.02) and none with Cu (F (4, 25) = 1.405, p = 0.261, p ≤ 0.05), Pb (F (4, 25) = 1.073, p = 0.391, p ≤ 0.05) and Ni (F (4, 25) = 2.492, p = 0.069). Results reveal that metal content in all samples exceed the WHO permissible levels for Cu (100 mg/kg), while those for Ni were below the WHO set standards of 50 mg/kg. Levels of Zn in three hospitals exceeded permissible level of 300 mg/kg while level of Pb exceeded WHO set standards of 100 mg/kg in two hospitals. Samples from four hospitals exceeded permissible level for Cd of 3 mg/kg. This study provides evidence that incinerator bottom ash is contaminated with toxic heavy metals to human health and the environment. This study recommends that hospitals should handle the bottom ash as hazardous wastes and there is need to train and provide appropriate personal protective equipment to healthcare workers, waste handlers, and incinerator operators and enforce compliance to existing regulation and guidelines on healthcare waste management to safeguard the environment and human health.

Effects of Using Municipal Solid Waste Incineration Tailings as Lightweight Aggregate on the Mechanical Properties of Specified Density Concrete

Municipal solid waste incineration tailings were used as lightweight aggregate(MSWIT-LA)in the preparation of specified density concrete to study the effects on compressive strength,axial compressive strength,flexural strength,microhardness,total number of pores,pore area,and pore spacing.The results showed that the internal curing and morphological effects induced by an appropriate quantity of MSWIT-LA improved the compressive response of specified density concrete specimens,whereas an excessive quantity of MSWIT-LA significantly reduced their mechanical properties.An analysis of pore structure indicated that the addition of MSWIT-LA increased the total quantity of pores and promoted cement hydration,resulting in a denser microstructure than that of ordinary concrete.The results of a principal component analysis showed that the mechanical response of specified density concrete prepared with 25%MSWIT-LA was superior to that of an equivalent ordinary concrete.It was therefore concluded that MSWIT-LA can be feasibly applied to achieve excellent specified density concrete properties while utilising municipal solid waste incineration tailings to protect the environment and alleviate shortages of sand and gravel resources.

Model Prediction and Optimal Control of Gas Oxygen Content for A Municipal Solid Waste Incineration Process

In the municipal solid waste incineration process,it is difficult to effectively control the gas oxygen content by setting the air flow according to artificial experience.To address this problem,this paper proposes an optimization control method of gas oxygen content based on model predictive control.First,a stochastic configuration network is utilized to establish a prediction model of gas oxygen content.Second,an improved differential evolution algorithm that is based on parameter adaptive and t-distribution strategy is employed to address the set value of air flow.Finally,model predictive control is combined with the event triggering strategy to reduce the amount of computation and the controller's frequent actions.The experimental results show that the optimization control method proposed in this paper obtains a smaller degree of fluctuation in the air flow set value,which can ensure the tracking control performance of the gas oxygen content while reducing the amount of calculation.

Investigation of basic properties of fly ash from urban waste incinerators in China

Basic properties of fly ash samples from different urban waste combustion facilities in China were analyzed using as X-ray fluorescence （XRF）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）. The leaching toxicity procedure and some factors influencing heavy metals distribution in fly ash were further investigated. Experimental results indicate that the fly ash structures are complex and its properties are variable. The results of XRF and SEM revealed that the major elements （〉10000 mg/kg, listed in decreasing order of abundance） in fly ash are O, Ca, Cl, Si, S, K, Na, Al, Fe and Zn. These elements account for 93% to 97%, and the content of Cl ranges from 6.93% to 29.18 %, while that of SiO2 does from 4.48% to 24.84%. The minor elements （1000 to 10000 mg/kg） include Cr, Cu and Pb. Primary heavy metals in fly ash include Zn, Pb, Cr, Cu etc. According to standard leaching test, heavy metal leaching levels vary from 0 to 163.10 mg/L （Pb） and from 0.049 to 164.90 mg/L （Zn）, mostly exceeding the Chinese Identification Standard for hazardous wastes. Morphology of fly ash is irregular, with both amorphous structures and polycrystalline aggregates. Further research showed that heavy metals were volatilized at a high furnace temperature, condensed when cooling down during the post-furnace system and captured at air pollution control systems. Generally, heavy metals are mainly present in the forms of aerosol particulates or tiny particulates enriched on surfaces of fly ash particles. The properties of fly ash are greatly influenced by the treatment capacities of incinerators or the variation of waste retention time in chamber. Fly ash from combustors of larger capacities generally has higher contents of volatile component and higher leaching toxicity, while those of smaller capacities often produce fly ash containing higher levels of nonvolatile components and has lower toxicity. The content of heavy metals and leaching toxicity maybe have no convincing correlation, and high alkali content of CaO greatly contribute to leaching toxicity of heavy metal and acid neutralization capacity against acid rain.

Chemical speciation and mobility of heavy metals in municipal solid waste incinerator fly ash

Chemical speciation is a significant factor that governs the toxicity and mobility of heavy metals in municipal solid waste incinerator fly ash. Sequential extraction procedure is applied to fractionate heavy metals(Pb, Zn, Cd, Cu, and Cr) into five defined groups: exchangeable, carbonate, Fe-Mn oxide, organic, and residual fractions. The mobility of heavy metals is also investigated with the aid of toxicity characteristic leaching procedure. In the fly ash sample, Pb is primarily presented in the carbonate(51%) and exchangeable(20%) fractions; Cd and Zn mainly exist as the exchangeable(83% and 49% respectively); Cu is mostly contained in the last three fractions(totally 87%); and Cr is mainly contained in the residual fraction(62%). Pb, Zn and Cd showed the high mobility in the investigation, thus might be of risk to the natural environment when municipal solid waste incinerator fly ash is landfilled or reutilized.

Effect of Water Washing Pre-treatment on the Properties of Glass-ceramics from Incinerator Fly Ash Using Electronic Arc Furnace

Production of glass-ceramics by sintering the molten slag obtained from electric arc furnace treatment of fly ash was investigated. The effect of washing pretreatment prior to melting the fly ash on the microstructure and properties of the glass-ceramics was examined. The results show that washing pretreatment of fly ash can decrease alkali metal chloride and increase network former in fly ash, which results in the increase of peak crystallization temperature of parent glass and strengthening of properties of bending strength and chemical stability of the glass-ceramics. The optimal heat treatment temperature for parent glass of washed fly ash is 1 173 K, at which the crystalline phase of glass-ceramics is composed of gelignite （Ca2A12SiO7） and akermanite （Ca2MgSi207）. Glass-ceramics produced at optimal heat treatment temperature are excellent in term of the physical and chemical properties and leaching characteristics, indicating attractive potential as substitute of nature materials.

Effects of Sulfur Compounds on Cd Partitioning in a Simulated Municipal Solid Waste Incinerator

The effect of sulfur compounds （including sulfur, sulfide, sulfite and sulfate）, initial concentration of heavy metal and operating conditions on Cd emission in municipal solid waste （MSW） incineration were investi-gated using a simulated tubular furnace and simulated MSW spiked with Cd. The concentration of Cd was meas-ured by inductively coupled plasma-atomic emission spectrometry （ICP-AES） after digesting the samples including bottom ash, fly ash and flue gas according to related USEPA methods. The results show that S and Na2S tend to in- crease Cd partitioning in bottom ash, whereas Na2SO3 and Na2SO4 tend to reduce Cd partitioning in bottom ash. The effect of sulfur compounds on Cd partitioning in bottom ash was in the sequence of Na2S〉S〉Na2SO3〉 Na2SO4. chemical equilibrium analysis is also performed to determine the effect of sorbents on Cd adsorption. The calculations show that S presents strong affinity for Cd and restrains Cd adsorption by SiO2, whereas when temperature rises to between 830℃ and 1030℃, Cd adsorption efficiency of SiO2 is over 80% and the efficiency of Al2O3 is up to 85%.

Effective incineration technology with a new-type rotary waste incinerator

The technology of steady combustion in a new type of rotary incinerator is firstly discussed. The formation and control of HCl,NOx and SO_(2) during the incineration of sampled municipal organic solid waste are studied with the incinerator. Results showed that the new model of rotary incinerator can effectively control and reduce the pollutant formations by post combustion.

Analysis of Medical Waste Incinerator Performance Based on Fuel Consumption and Cycle Times

A detailed assessment of an incinerator based on fuel consumption and cycle time data is presented in this paper. The study was conducted at Temeke district hospital for 22 months consecutively covering 654 days of daily data collection on fuel consumption and cycle times. The composition for the medical waste incinerated varied between 15% and 35% for sharps waste and between 65% and 85% for other waste, with mean values of 25% and 75%, respectively. The results revealed poor performance of the incinerator due to higher fuel consumption (above 30 L/cycle). The incineration cycle times were observed to range between 2 and 4 hours, all of which were too high for the loading rates observed (55 - 214 kg). A strong dependency of diesel oil consumption on cycle time was observed due to lack of temperature control leading to continuous fuel flow into the burners. The incineration capacity was very low compared to other incinerators in terms of tons per year. This paper gives an insight on the factors affecting incinerator performance assessed based on diesel oil consumption and cycle times. It can be generalized that the incinerator performance was poor due to several factors ranging from poor incinerator design, operator skills, waste management practices, waste storage practices, etc. The hospital was advised to install a new incinerator with short incineration cycle time (30 - 40 minutes) and lower fuel consumption (10 L/cycle) at a loading rate of 200 kg/cycle.

A Burning Experiment Study of an Integral Medical Waste Incinerator

Mass burning of the medical waste is becoming attractive in China because Chinese government has banned landfilling of medical waste. Many advantages can be found in this method, such as reduction in waste volume, destruction of pathogens and transformation of waste into the form of ash. However, the medical waste with high moisture in China is not suitable to be treated in the present direct mass burning incinerators. In this paper, a novel integral incinerator is developed with combining a feeder, a rotary grate, a primary combustion chamber (PCC) and a “coaxial” secondary combustion chamber (SCC) into a unique unit. Its capability is 10 ton/day. As the air excess level in the PCC was only 40% stoichiometric ratio, the PCC acted as a gasifier. The 1.0 excess air ratios in the SCC preserved the purpose of full combustion of flue gas. Temperature and pollutants concentration in the SCC were measured to understand the combustion behavior of volatile organics. Emission concentrations of pollutants before stack were also tested and compared with the China National Incineration Emission Standard.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in flue gas emissions from municipal solid waste incinerators in China

Polychlorinated dibenzo-p-dioxins and furans （PCDD/Fs） emissions in flue gas from two types of municipal solid waste incinerators （MSWIs） most commonly used in China were investigated in this study. The selected incinerators include two grate-type MSWIs： MSWI-A （350 t/d） and MSWI-B 050 t/d）, and two fluidized bed MSWIs： MSWI-C （400 t/d） and MSWI-D （400 t/d）, which are all equipped with semi-dry lime scrubber and bag filter except MSWI-D equipped with cyclone and wet scrubber （WS） as air pollutant control device （APCD）. Results indicated that the emission concentration and the international toxic equivalents （I-TEQs） of the PCDD/Fs from the stacks were in the range of 1.210-10.273 ng/Nm^3 and 0.019-0.201 ng I-TEQ/Nm^3, respectively. They were greatly lower than the emission regulation standard of PCDD/Fs in China （1.0 ng I-TEQ/Nm^3）. However, only the PCDD/Fs emission level from MSWI-C was below 0.1 ng I-TEQ/Nm^3. Although the homologue profiles were distinct, the contributions of the 2,3,7,8-subsituted congeners to the total I-TEQ were similar among all the investigated MSWIs. Two major 2,3,7,8-substituted congeners, 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD, account for 47% and 9% （average values） of the total I-TEQ values, respectively. The correlation between PCDD/Fs levels and composition of flue gas was also discussed.

Steam Oxidation Resistance of Nitride Bonded Silicon Carbide Refractories for Waste Incinerators at Elevated Temperatures

Steam oxidation resistance of Si3N4 and Si2N2O as well as SiAlON bonded SiC refractories at 900℃was tested according to ASTM-C863.Phase composition and microstructure before and after oxidation were analyzed by XRD and SEM.The results show that Si3N4 and Si2N2O bonded SiC refractory presents better steam oxidation resistance than SiAlON bonded SiC.For Si3N4 and Si2N2O bonded SiC,the oxidation speed is higher with more pronounced volume expansion in the early 100 h;afterwards,the volume expansion slows down gradually and starts to level off after 300 h.It is considered that the high silica glass phase formed during the oxidation covers Si3N4 and Si2N2O,and SiC as a protective layer and fills the open pores.But for SiAlON bonded SiC,the volume expands gradually and constantly with the increasing oxidation duration even after 500 h,due to the continuous formation of mullite transformed from oxidation products and Al2O3 in SiAlON.

Validation for the Determination of Extractable Metals in Ashes from Biomass Incinerators by ICP-OES

Biomass ashes contain valuable elements for plant growth, but also often high amounts of harmful heavy metals which limit their reuse in forests and on grassland. For monitoring metal concentrations, a fast and reliable method allowing the quantitative determination even at trace levels is mandatory. Therefore an analytical method consisting of an acidic microwave assisted digestion prior to ICP-OES measurement was optimized. The elements of interest were AI, As, B, Ba, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Sb, St, Ti, V, and Zn. A validation including the following parameters was performed for each analyte： limit of detection, limit of quantification, recovery by spiking experiments, accuracy by analyzing a certified reference material, reproducibility （wihtin-24 hours, 4 and 7 days）, linearity, and uncertainty of measurement. Two standards series were used for calibration - one with 1 M HNO3 and one with additionally 2 g/L Mg（NOD2 to investigate the elimination or decrease of possible matrix effects. Both calibration methods showed very good recoveries. The method optimized allows the determination of the relevant elements covered by the recommendation of the Austrian ministry for agriculture and represents thus an appropriate tool for monitoring the metal contents in biomass ashes.

INCINERATOR FOR FIAMMABLE RADIOACTIVE WASTES

An incinerator was built up in 1987 in Shanghai. In this paper, the devices of the incinerator, main parameters of the process, the results of combustion tests for nonradioactive waste and simulated radwaste are given. The instructive information for radwaste treatment were provided.

Determination of thermal parameters for waste liquid and gas fluidized-bed incinerator

Equations are established for calculation of dense and dilute phase zone combustion temperatures, quantity of auxiliary fuel and thermal efficiency for a fluidized bed incinerator with coal burnt as auxiliary fuel, waste liquid burnt in dense phase zone and waste gas burnt in dilute phase zone while there is a heat transfer, thereby providing theoretical basis for design of waste liquid and gas fluidized bed incinerators.

Geo-environmental application of municipal solid waste incinerator ash stabilized with cement

The behavior of soluble salts contained in the municipal solid waste incinerator(MSWI) ash significantly affects the strength development and hardening reaction when stabilized with cement.The present study focuses on the compaction and strength behavior of mixed specimens of cement and MSWI ash.A series of indices such as unconfined compressive strength,split tensile strength,California bearing ratio(CBR) and pH value was examined.Prior to this,the specimens were cured for 7 d,14 d,and 28 d.The test results depict that the maximum dry density(MDD) decreases and the optimum moisture content(OMC)increases with the addition of cement.The test results also reveal that the cement increases the strength of the mixed specimens.Thus,the combination of MSWI ash and cement can be used as a lightweight filling material in different structures like embankment and road construction.

Performance of a Large-Scale Medical Waste Incinerator in a Referral Hospital

The aim of the study was to analyze the performance of large scale incinerator installed in a referral hospital. The study involved weighing and loading infectious waste of different composition (sharps and other waste), recording temperatures in the primary and secondary chamber with time, fuel used and collecting and weighing the bottom ash for 65 days. The analysis shows that the incinerator on average uses 362 L/day (45 L/h) to incinerate 945 kg of medical waste (40.8 kg/day of sharps waste and 904 kg/day of other waste), generating 51.2 kg of ash daily. The observed fuel consumption rate was too high necessitating corrective action. The average weight reduction was 94.6%. The study shows that the average sharps waste composition for medical waste incinerated was 4.3% and other waste was 95.7%. The incinerator capacity ranged between 100 and 130 kg/h. The fuel effectiveness ranged between 2.0 and 3.0 liters of diesel per kg of waste incinerated. The fuel effectiveness increased linearly with total waste incinerated and incinerator capacity, respectively, depending on the fuel consumption rate.

Effects on Strengths of Cement Mortar When Using Incinerator Bottom Ash as Fine Aggregate

The main purpose of this paper is to study the feasibility of using the Incinerator bottom ash fine aggregate to replace natural fine aggregate in the cement mortar products. The research adopts high cement content mortar to conduct the experiment, in which the weight ratio of cement/aggregate is 1/2. The experiment uses Incinerator bottom ash fine aggregates, which passes through #16 sieve, and natural sand of the same size as the aggregate, and separates mortar specimens in- to two main categories based on different W/C ratio. Moreover, different proportions of furnace slag and F-class are used to replace a portion of cement so as to explore the influence on strength of Incinerator bottom ash aggregates mortar by adding the two admixtures. The study shows that, based on the 1:2 cement/aggregate weight ratio, Incinerator bottom ash fine aggregates mortar, unit weight around 1.8 g/cm3, is 20% lighter natural fine aggregate mortar, unit weight around 2.2 g/cm3. The Incinerator bottom ash fine aggregates mortar can only reach 60%-70% the compressive strength of natural fine aggregates mortar. Direct tensile strength and flexural tensile strength tests are 15% and 30% of compressive strength respectively, due to the irregular strength development, which does not follow general concepts, such as low W/C ratio and mineral admixtures will not necessarily help in strength development in Incinerator bottom ash fine aggregates mortar.

Prediction of NO_(x)concentration using modular long short-term memory neural network for municipal solid waste incineration

Air pollution control poses a major problem in the implementation of municipal solid waste incineration(MSWI).Accurate prediction of nitrogen oxides(NO_(x))concentration plays an important role in efficient NO_(x)emission controlling.In this study,a modular long short-term memory(M-LSTM)network is developed to design an efficient prediction model for NO_(x)concentration.First,the fuzzy C means(FCM)algorithm is utilized to divide the task into several sub-tasks,aiming to realize the divide-and-conquer ability for complex task.Second,long short-term memory(LSTM)neural networks are applied to tackle corresponding sub-tasks,which can improve the prediction accuracy of the sub-networks.Third,a cooperative decision strategy is designed to guarantee the generalization performance during the testing or application stage.Finally,after being evaluated by a benchmark simulation,the proposed method is applied to a real MSWI process.And the experimental results demonstrate the considerable prediction ability of the M-LSTM network.