ASPECTS REGARDING THE KINSHASA URBAN LANDFILLS ASSESSMENT AND PROPOSALS FOR SUSTAINABLE DEVELOPMENT

Landfill management is one of the major issues in the application of sustainable development principles and ecological maintenance of the cities. Promoting their appreciation, and even more preventing for their minimization, are at the heart of many debates within the scientific community, local communities, companies and civil society. The city of Kinshasa is demographically growing much too fast, its capacity to manage the waste produced by 10000000 inhabitants is more than overwhelmed. The question is “WHAT CAN BE DONE?” Today it is acknowledged that these quantities of waste can be fruitfully put to use rather than looking at it simply like at a bothersome, congesting and polluting phenomenon. We have now to consider this above all a “secondary” raw materials resource. The problem is not the amount of waste, but the inability of governments and waste disposal companies to get rid of it. The city of Kinshasa seems today to have a certain disconnection from its environment because of the impacts of human actions these last fifty years. In addition to household refuse and pollution causing an unsanitary environment in most parts of the city, one particularly notes the consequences of uncontrolled urbanization and poor waste management, resulting in widespread insalubrity of the city. The present paper was assessed the situation regarding the urban landfills in Kinshasa by using field evaluation and population questioning.


INTRODUCTION
The uncontrolled urban waste situation in Kinshasa produces a direct negative impact on public health and environment.These effects can be summarized as following: air pollution and emission of offensive odors due in particular to methane vapor's coming from waste burning; chemical and organic pollution of water resources which become enabling environments for mosquitoes and vermin breeding, and representing thus a threat to health, either directly by their consumption, or indirectly by the consumption of agricultural products irrigated with polluted water; degradation of city's aesthetic aspect and immobilization of productive lands due to the presence of non-biodegradable products (e.g.: plastic bags, demolition waste, etc.); free access to animals to urban waste, leading them to ingest solid and toxic materials.The city urban waste disposal in Kinshasa is generally done in the absence of proper hygienic conditions and with obvious adverse consequences on the environment.Indeed, in the strict sense of the word, the efficient management of urban waste consists in city's garbage disposal, because storing them in inhabited areas pollutes the environment and affects the quality of life [1][2][3][4][5][6].
Kinshasa has indeed several waste disposals without recovery control level, without fire control, covering material, without mechanical compaction and waste levelling.Here, the waste is simply abandoned: the surface waters and the groundwater table are contaminated, the soils are polluted, the insects proliferate, the rodents and the animals roam, unpleasant odors, microbial pathogens are developing, the smoke is permanent, etc.
In order to establish a clearer situation on the waste management situation in Kinshasa was adopted the field investigation method (direct investigation and discussions with the population).Also in our methodology was used documentary research (national documents), literature research, quantitative and qualitative surveys; results of the surveys and data processing.

ANALYSIS METHODS AND TECHNIQUES
Our methodology is built on two main research strategies.On the one hand, there is the inductive-empirical method based on direct observations, and, on the other hand, there is the hypothetic-deductive method guiding our survey and inquiry process, from preliminary questionings.As indicated above, our methodology is built around documentary research (consulting works and documents), internet research, field observations; quantitative and qualitative surveys; results of the surveys and gathered data processing.

Field surveys
Under this analysis, we have focused on the direct survey, this enabling us to understand better the city and the diversity of its communes their population.This approach allowed us to discover aspects that were not covered by official investigations and not to be found in statistics.These mainly include the spatial distribution of investigations, the relations between them, and the collective and specific perception of household waste, domestic refuse, and the behavior of city-dwellers towards waste.Therefore, we went through by direct observation, by interviews and surveys, in order to better understand the problem of household waste management in Kinshasa, within a sustainable development context.

Size and choice of sample
The size of the referred sample must be basically according to the representativeness of indicators and accuracy, while maintaining the investigation within reasonable time limits and our possibilities.This, the chosen sample was the one providing representative indicators for all communes of Kinshasa.
In fact, given the real difficulties to proceed and to divide the city into homogeneous sectors, since they do not exist, a simple random method was applied, with a large sample with great dispersion, method which allowed us to have good household estimators.
Through this method, we have chosen a 600 household sample, 50 of which by communes.The concerned households have not been pre-selected.More than this, no preliminary selection criterion has been imagined.We have simply relied on the goodwill and availability of respondents, this taken into account the reluctance, even hostility of certain people to respond to our questions.However, we have tried to respect the quota of households to be surveyed by enumeration area.

Data processing
We proceeded at the same time to conceptual as well as to quantitative treatment.The first consisted mainly of the description and location of observed facts and data gathered on the field.The description was built around keywords and previously defined concepts.We wanted this description to be precise and schematic, in order to reach a thorough and methodical explanation of the causes and the effects of phenomena revealed on the field.The latter allowed us to gather the 600 survey cards administrated on the field.Thus, our processing concerned 600 surveys.It was carried out by means of OriginPro 8.5.0 and XLStat software.

Uncontrolled or random discharge
The situation inherited from colonial period, when Kinshasa was first of all equipped with transit landfill and garbage containers, then with final landfill, along the river, at the current location of Navy Headquarters, did not serve as a model for the urban waste disposal.The fact is that now in Kinshasa the waste transporters do not have appropriate sites to dispose of the garbage in a proper manner.Moreover, the sites that formerly housed the waste disposal have been anarchically parceled out by the city authorities [2].
As a consequence, households that cannot afford to pay a pushcart person to evacuate their garbage, discharge their loads in open air.Fig. 1.The distribution of respondents by the presence of random landfill in analyzed commune: Limete, Bumbu, Lemba, Selembao, Barumbu, Kimbanseke, Ndjili, Masina, Kisenso, Kalamu, Lingwala, Ngaliema.
After readout of Figure 1 output, it was revealed that 45 % of the population of Kinshasa evacuate their garbage in an uncontrolled discharge, against 40 % who do not evacuate the garbage in a random discharge and 14 % of households in Kinshasa did not reveal their answer on this matter.
Kinshasa has indeed several waste disposals without recovery control level, without fire control, covering material, without mechanical compaction and waste leveling.Here, the waste is simply abandoned: the surface waters and the groundwater table are contaminated, the soils are polluted, the insects proliferate, the rodents and the animals roam, unpleasant odors are loose, microbial pathogens are developing, smoke is permanent, etc. [2,6,7].

Landfilling of the waste producers
The investigations we have carried out within this analysis show that according to the results in Figure 2, currently (2013) only 10 % of households in Kinshasa throw their garbage.This may be explained by the fact that these households do not have enough space within their parcel to dig a garbage hole, because of the huge parcel fragmentation observed these last decades in Kinshasa.
When the city had in 1989 about 3.5 million inhabitants, the CNAEA report 1990 had mentioned that almost 30 % of Kinshasa population threw away their household waste in the courtyard.This means about 113000 tons each year.1996 PNA reports showed that 1.5 million inhabitants threw away their household waste.This means about 168000 tons each year.If these figures represent the general situation in the entire city, there are also targeted studies confirming the aforementioned facts.In Makala, for instance, 44 % of households threw away their garbage in the courtyard [5,6].In Bribano slum, at Kingabwa, 83 % threw their garbage within the parcel and at Masina there are 7 % doing the same.

Incineration
The analysis of the data in Figure 2 concerning the incineration shows that 12 % of Kinshasa households dispose of their domestic refuse by incineration, and it is more in the commune of Kisenso where more than half of the households, i.e. 52 %, use this way of getting rid of the garbage, followed by the commune of Kimbanseke, where 28 % of the households burn their waste.This may justify the thesis based on which the incineration is particularly done by certain households in peripheral areas.This practice, which is not however used systematically, it is common mainly in a random landfill, which are under fire almost permanently.This uncontrolled incineration may be a source of pollution, depending on the quality of the burnt waste and the duration of the exposure.

Composting
In the city of Kinshasa, the waste composting is not a very common practice, the results of the investigations carried out in Kinshasa households showing in Figure 2 that only 7 % of Kinshasa households practice composting.However, several handicraft compost pits existed in Kinshasa province, but they did not prove to be most efficient because of the offensive odors and due to the lack of the market.
Studies about the household waste disposal methods in Kinshasa show that some households transform their garbage in manure for their vegetable gardens [6][7][8][9][10].

Urban waste impact assessment in Kinshasa
The city of Kinshasa seems today to have a certain disconnection from its environment because of the impacts of human actions these last fifty years.In addition to household refuse and pollution causing an unsanitary environment in most parts of the city, one particularly notes the consequences of uncontrolled urbanization and poor waste management, resulting in widespread insalubrity of the city.Ongoing municipality efforts or private initiatives show improvements in certain sides of the city, but a huge amount of works still remains to be done, and mostly lessons to be learned on what we must not do in the future urbanization [6][7][8][9][10][11][12][13].

Impact on human environment
The sanitation infrastructure deficit is important in the city of Kinshasa.There is a big discrepancy between services and population growth, and many neighborhoods are poorly equipped, which causes the inequity in the access to sanitation.Consequently, several diseases occurred with impact on the human environment.The readout of this graphic shows that 80 % of Kinshasa population suffer of malaria, 68 % of the population suffer of typhoid fever, 29 % suffer of diarrhea, and 15 % suffer of amoebiasis.These data prove fully our hypotheses according to which uncontrolled waste disposal is the origin of several diseases are due to insalubrity (Figure 3).Fig. 4. Survey distribution according to the connexion between diseases and waste: Limete, Bumbu, Lemba, Selembao, Barumbu, Kimbanseke, Ndjili, Masina, Kisenso, Kalamu, Lingwala, Ngaliema.
The readout of Figure 4 on the connexion that may exist between waste and diseases showed that, within the population of Kinshasa, 60 % of the respondents confirmed that there was a tight connection between random disposal and their diseases, 23 % of the respondent households think there is no connexion between uncontrolled disposal and their diseases, and 17 % of the respondents refused to share their opinion on this matter.

Discharge impact and disturbances on physical environment a) Impact on water
The amount of water used in the city of Kinshasa comes more than 80 % form N'djili River.In the same time, directly or indirectly, the final destination of part of the waste is this river.Indeed, the run-off waters bring part of the waste in formal or informal depositions in the city's waterways, these latter flowing N'djili River to end up their fall in Congo River.b) Disturbances due to wild discharges: -Odours: the odours generated by discharges have several sources: the materials themselves, gases released by discharges, leachates; -Leachates: the discharge leachates are mainly produced by rain waters infiltrating into the ground, the discharge humidity and imported waters leaking into the ground; -Biogas: the biogas generated in the body of the discharge is due to waste microbial decomposition or to physico-chemical phenomena.In the first situation, the humidity content in the body of the discharge and the organic matters condition the production of biogas; -Dust emission: the presence of random discharges may cause dust emissions in different places.These dust emissions, as well as paper and plastic films dispersion, may also be caused by the wind.

Landfill sustainable development approach in Kinshasa
As the city of Kinshasa develops and the population becomes more and more aware of the connexion between the quality of life and that of the environment, people in charge of this aspect became forced to provide a better environmental frame for today's and tomorrow's generations.
Our objective is now to propose practical and precise steps, necessary for the improvement of Kinshasa landfill management, in view of a sustainable development.Thus, the implementation of this draft must take into account three components: technical and practical; political and economic; planning and development.

Technical and practical aspects
The technical and practical aspects to be implemented within the framework of this proposal shall be based on the knowledge of the types of waste regularly produced by Kinshasa households, and of the produced quantity, to allow us to issue solution proposals leading us to a sustainable development.These technical aspects concern the planning of collecting systems, transportation, disposal and valorization.
Thus, the Kinshasa waste life-cycle we propose implies five stages distributed in time and space as following: waste generation; sorting and collecting; valuation by recycling; treatment of non-recoverable fraction; final discharge in a dedicated sit of an eco-compatible refuse.
This practical diagram (Figure 5) favours the waste conversion by recycling and/or composting, instead of throwing it away.Since not all the waste can be converted, only a small proportion is to be sent to the Centre d'Enfouissement Technique (Landfill Site).This will offer this final landfill the possibility to exist for a long time.

Sorting and collecting
The sorting is a key operation for the implementation and success of the valorization of waste, such as composting, biogas production and even for recycling.Indeed, once the organic matter mixes with other unwanted materials such as recyclable materials, plastic or batteries, the contamination degree increases and certain recyclable materials, such as cardboard, perish.This diagram (Figure 6) shows that waste must undergo a first sorting at the source, at the producers; this first sorting will consist of separating the organic waste from special household waste and recoverable industrial waste.After the transport of these sorts towards the transit sites, a second sorting, more thorough, shall be carried out in order to separate the organic waste, the non-organic waste and special waste; the organic waste are to be sent to composting center, while in the case of non-organic waste one part is to be recycled in order to be valued in a similar product, and the remaining part of the non-recoverable waste is to be sent to the Centre d'Enfouissement Technique (Landfill Site).

Proposal for waste recycling by composting
Composting the household waste in Kinshasa describes the significant proportion of organic matter, and this is why composting may be an option more appropriate in view of household waste recycling.
The composting approach is interesting for the city of Kinshasa and for the peri-urban population.This will allow indeed the reduction of solid household waste and will also improve the living conditions of the urban and peri-urban population.This will profit from the compost trading and also from the increased agricultural productivity.
This is justified by the fact that in Kinshasa the crisis suffered by the population forced most of the people to enter into urban and peri-urban agriculture, and as a result in almost every street of the city it is not anymore a surprise to see market gardening, even on the main boulevards.Hence the necessity to install a compost bin in every commune in order to bring together producers and consumers.

Proposal to transform urban waste into biogas in Kinshasa
As Kinshasa is facing the major issue of waste management, the biogas technology will allow transforming the waste into energy.This will not only clean the environment, but it will also bring a solution to different thorny problems such as lack of power or compensating the load shedding.
Here, within the solid waste management diagram, we propose producing the biogas from city's solid waste.This proposal is going to contribute to the sanitation of the city of Kinshasa, given that this process requires the combination of faeces and household waste, thus offering a source of clean energy.

Proposal of recycling plastic waste
In Kinshasa, recycling is practiced for certain types of waste, but not on large scale.For example: a) Metal and scrap iron is picked up by individuals who sell it to Limete, 17th street, to Chinese and Indian buyers; the latter export it as raw material into their countries.We have to underline the fact that, at this level, recovery is almost total, since all over the city a metal and scrap buying action was carried out by pushcart persons and other people engaging in this kind of work in order to sell to potential buyers.
b) As for cardboard, there is a factory in Limete buying a small quantity for the production of packaging material and especially toilet paper.c) A small quantity of bags are reused by citizens and several companies recover heavy plastic for the production of cups.
This experience on plastic bags recovery is an opportunity not only in the fight against insalubrity in the city of Kinshasa, but it also contributes to the development of a popular economy against poverty, given that selling this product creates income for several hundred people in the field of collecting and recovering waste.

Development of transit sites
The city of Kinshasa, as we will always say it, encounters problems with regard to waste collection.Indeed, some parts of remote neighborhoods are not accessible to large trucks, such as the ones for picking-up the garbage.The waste collection vehicles cannot move easily through the very narrow streets.On the other hand, some neighborhoods have a very poor road network that would not allow vehicles to get through.In order to solve this problems, the RATPK (Public Works Sanitation Department) must set aside transit venues to facilitate the solid waste collection all over the city and to optimize the transport to the final landfill controlled by the Centre d'Enfouissement Technique (Landfill Site) to be developed.

Development of landfill centers
In the city of Kinshasa, the waste disposal never meets the necessary guarantees to avoid not only the water, soil or air pollution, but also to ensure an efficient site management.Most often, disposal sites have been implemented with little apprehension of the problems they might create.
Controlled landfilling remains distinctly a good alternative.However, if waste sorting has not been successful, this option if far from being ecological.
Therefore, in addition to implementing a waste sorting policy and valorization of their organic part, it is essential to set up a controlled landfill for the non-recycled waste.This measure aims to solve the solid waste storage and treatment issues.It initially includes the improvement of Centre d'Enfouissement Technique (Landfill Site) in Mpasa, while waiting for extensive studies to be conducted and then for the development of a new Centre d'Enfouissement Technique (Landfill Site) in Mitendi (Figure 7).

CONCLUSIONS
The sustainability of the actions proposed within the strategic plan depends on RATPK's ability to better organize the waste collection and to ensure the maintenance and servicing for the infrastructures to be set up.
The relations between the different actors to be involved in waste management are to be defined by community contracts.The plan's sustainability shall also be ensured by the fight against solid waste dumping in nature, which shall be done by: -Strengthening of household waste pre-collection system and purchase of small equipment for the benefit of the associations; -An increased number of transit stations meant to receive the household waste which was usually discharged in the streets of the city.
Moreover, the contracts to be signed between the different actors in each commune shall allow an appropriate waste pre-collection.These contracts will also allow to different associations to dispose of appropriate resources to ensure the sustainability of their activities and to set up alternative mechanisms for their equipment.In fact, the information, education and raising awareness activities in favor of beneficiary associations, shall highlight the correlation between the unhealthy environment and the prevalence of all associated diseases, and shall allow the sustainable fight against habits such as throwing waste in inappropriate places.The proposed draft on waste management involves all segments of the urban population.The households, gathered in associations, shall be able to purchase contracts for pre-collecting, composting and organic waste supply for the production of biogas.
This system provides a double-edged advantage: -Households, the first to be concerned by the waste problems, will become now the first actors in its management; -When purchasing these contracts, households shall be able to earn money and thus improve their standard of living.
To conclude, the proposed actions are based on a participatory approach and allow a better environment management, an improvement of urban and peri-urban population's standard of living.They shall engage an increased accountability of the populations and a better organization of the main communities as well as the promotion of small operators.Also the community may try achieving integrated waste management through the implementation of common actions: officials-population in reflection of real cases of success (from EU or USA).