Nature works sustainably through various cycles. Organic wastes feed the soil processes and the soil, in turn feeds the plants. Soil organisms such as earthworms use the organic wastes as their food and derive energy to carry out the vital function of producing balanced plant nutrition. Plants that get such balanced nutrition are free from any pest attack. When we break this cycle, we create two loose ends (we call them problems), that of pollution due to neglected organic wastes and expenses on synthetic fertilizers/pesticides. Neglected organic wastes get piled up and breed pests (such as cockroaches, ants, rodents, etc.) and also produce odour.
Pathogens that may originate from sick persons also can proliferate in such waste heaps and create health hazard. Often incineration of organic wastes is recommended to kill the pathogens, but valuable organics too get incinerated, producing greenhouse gases. Even the conventional composting also amounts to burning about half of the organics in the garbage, producing greenhouse gases and biological ash called compost. Biomethanation, too, is a wasteful process. One mole of methane in biogas is associated with one mole of CO2. Organics that converted into CO2, thus are available neither as fuel, nor for the soil processes. There has been, thus, a need to develop an eco-friendly process to use our wasted organic resources (better term for “organic wastes”). This was developed during 1987-1996 and popularized among the urban gardeners, giving an alternative to the use of chemical fertilizers and pesticides (Bhawalkar, 1996). This paper reviews the successful adoption of this “closing the loop” strategy and discusses the mechanisms behind this simple eco-friendly process of organic wastes recycling.
Urban gardening needs to be encouraged to cool down the urban concrete structures and also to take care of air pollution created by burning of fossil fuels by our automobiles. Since garden gets the last priority after the building, roads and the parking area, there is hardly any space left. Terraces however, continue to get exposed to the hot sun. The diurnal temperature fluctuations can weaken the slabs and start leakages over the years. It is thus necessary to develop green rooftops to keep the terraces cool and reduce urban air pollution. But the gardening technique needs to be eco-friendly. Use of chemical fertilizers, for example, will produce acidic leachate and damage the slabs. Chemical fertilisers also cause nutrient imbalances, this increases the pest attacks and leads to the use of toxic sprays. Urban gardeners do the gardening for pleasure and do not wish to use the toxic sprays that are also harmful to man and several friendly creatures. We thus, need to harness all the techniques of organic agriculture to develop urban gardening.
Technique of In-situ Recycling
Bhawalkar Ecological Research Institute (BERI) that was known as Bhawalkar Earthworm Research Institute (BERI) from 1980 to 1995 has been in the field of waste management. BERI realized that instead of focusing on collection, transport and disposal of garbage, it is necessary to integrate garbage into plant growth cycle. Only plants can consume our solid, liquid and gaseous > wastes(that is how, Nature is designed) and only plants can produce our oxygen and other needs such as food, fuel, fibre, fertilizer, medicines, etc. Current practice of dumping garbage in the low-lying areas outside the current city limit has no logic, it soils the groundwater through production of acidic leachate that also has heavy metals and also pollutes the air. This leads to pollution of rain. So the pollution comes back to us in the form of air or water.
If we observe the Nature, plant and animal waste just falls on the soil, the soil is rarely exposed to sunlight. The organic mulch also reduces soil erosion due to heavy rainfall. Organic mulch is under constant stage of accumulation and decomposition and this liberates the plant nutrients needed > for new growth. CO2 is the most limiting plant nutrient, and then are the other plant nutrients such as nitrogen, phosphorus and other macro and micronutrients. The fact that CO2 is the most limiting plant nutrient can be seen from the increased plant production in greenhouses that can provide upto 1,000-2,000 ppm CO2 as compared to 400 ppm in the air. In fact, the success of green revolution that used high amount of nitrogenous fertilizers (such as urea) was based on the soil-mining reaction that converts to soil’s fixed organic reserve into CO2. This reaction is that of denitrification and is triggered only when we provide large amount of soluble nitrogenous fertilizers. Soil organic matter levels have been reduced from 2-3 percent to 0.1 to 0.5 percent and when there is nothing to mine, the chemical fertilizers are not producing the results now. This mining technique also spoiled the groundwater and river water and produced food with residual nitrates. It is reported that pests attack a crop only if the crop has residual nitrates. During storage too, food spoilage (due to fungi, insects and rats) is due to residual nitrates. Organic farming has reduced pest problems and the organic food also has better keeping quality. It is also has higher nutrition (in terms of higher dry matter, vitamins, minerals and lower nitrates). In general nitrates have negative impact on human body and mind, so one can appreciate the Natural mechanism of pests and food spoilage as being the quality control mechanisms of Nature (Lampkin, 1990). If we suppress these with the help of toxic chemicals, we end up consuming toxic food with nitrates and toxic chemicals and this leads to cancer.
Before feeding the raw garbage onto the soil below a growing plant, to simulate what happens in Nature, it was realized that one needs to put a small amount of vermiculture powder(about 1 gram per pot or small plant on the ground) to enliven the soil. Only a living soil can consume the organic food. If we feed organic food onto a dead soil (soil that has a predominance of nitrifying and denitrifying bacteria, that is, a chemically fertilized soil), then the organics get accumulated and get putrefied to produce odour. This attracts the pests such as cockroaches, ants, rats, termites, scorpions, snakes, etc. These natural creatures are the bioindicators of soil that is overfed with organic food (Bhawalkar, 1996). The act of adding the vermiculture powder is aimed at increasing the soil’s appetite by introducing a selected culture of soil’s beneficial microflora and fauna. If 1 m2 of dead soil gets 10 grams of vermiculture powder, it can consume upto 1 kg of organic food per m2 each day, without attracting any pests. A family of 5 persons generates this amount of organic waste. It is thus necessary only to allot 1 m2 of gardening area per family. This can be in the balcony or on the terrace too. It can also be in the form of 7 pots and these can be kept in the steel grill that is common nowadays outside a window. One pot can be fed each day, the organic food gets used up within 7 days and one can feed on 7-days’ rotation.
It is estimated that about 10,000 families are using this method of “In-situ utilization of organic food in organic garden” in Pune and other cities, for more than 10 years. This was pioneered by Shrimati Lata Shrikhande of Kanchan Lane (off Law College Road) in Pune. She has been recycling her garbage since 1980 and has inspired thousands of families to start garbage-fed terrace gardens in Pune and several other cities. With proper communication through modern media, it is easier to spread this further. In fact, each new building in Pune is motivated to start such garbage-recycling activity today, under the guidelines issued by the Supreme Court.
In Mumbai, Joshi Lane in East Ghatkopar has used this method for the past 8 years successfully and inspired others too. BMC has involved this method in ALM (Advanced Locality Management) movement. In Joshi Lane, 1 potted plant per person is kept on the roadside gutter. One person collects the biodegradable garbage each day from all the families and feeds into these pots, the other fraction of garbage, such as glass, paper, metals, plastics, etc. arising mainly from the modern packaging trend, is handed over to the ragpickers (resource recycling agents). In Mumbai, BMC spends 1.5 Rs/kg on collection, transport and disposal of garbage. The environmental cost of this improper disposal is not included in this figure. Now, carbon credit is2 available for any activity that prevents production of CO2 and in fact, converts CO2 into organic biomass. If families that take up such urban gardening activity, are given a rebate from the municipal taxes, equivalent to Rs 1.5 per kg of garbage recycled this way, this concept will pick up automatically. The environmental benefits of this eco-activity will be a bonus.
It will be interesting to discuss the key issues involved with this garbage recycling activity. These are presented in the Q&A format below.
Q: Why do people hate garbage and want somebody (governmental agency) to take it away from them?
A:Garbage, or in general organic wastes, creates unpleasant signals such as odour, pathogens and pests. Hence the fear about garbage. But just dumping the garbage outside the city limits is hardly a solution. We have to understand the root cause of garbage pollution and also use 3 R’s: Reduce, Reuse and Recycle to arrive at the true solution.
Q: What is the root cause of garbage pollution?
A: Garbage or organic wastes create pollution due to the nitrates in them. Food spoilage is due to nitrates, lot of food gets spoiled and becomes garbage. Out of the 3 R’s, first R is about reducing the production of garbage. This is possible if we resort to organic gardening and thus, inspire the farmers to take up to organic farming. The nitrates in the garbage can also be utilized if garbage is used to feed the living soil created by adding 10 grams of vermiculture powder per m2 of garden. This is one-time dose and takes care of all garbage problems and in fact, converts garbage into gold (plant biomass and oxygen).
Q: How can one prove that all the garbage problems are due to nitrates?
A: One can simulate garbage by taking any combination of carbohydrates (sugar, starch, cellulose, lignin, etc.), proteins and nitrates. Initial experiments can be only with carbohydrates and nitrates, to understand spoilage of mango pulp/juice, for example. One can see that mild signals of harmless insects come at low ratio of nitrates/carbohydrates, at increasing ratio one finds biting creatures, and at higher ratio, one finds obnoxious odour and pathogen growth. Carbohydrates without nitrates, such as heap of dry leaves, cotton, paper, etc. cause no pollution and hence these materials get used by the society. One can go on adding increasing amount of nitrates in these materials and see how they create the pollution signals. Material with carbohydrates and proteins, such as well-washed paneer can last longer than paneer laced with nitrates. One can create an odour-bomb (typically a dead rat odour) by putting nitrates in increasing amount on paneer. Since the exact ratio needed to produce a given pollution signal depends upon the temperature, exact figures cannot be given, but the trend that increasing nitrates cause increasing amount of pollution is obvious. In fact, BERI has now developed a BIOSANITIZER that just locks up the nitrates and solves the garbage pollution problems in a minute. The locked nitrates are available only to plants and not to nuisance-causing pests, pathogens or for odour production. One can now use the BIOSANITIZER to convert garbage into manure that can be used later when needed. A family needs a space of 0.2 m2 only to process garbage using the BIOSANITIZER now and costs Rs 1,000/-. This is the cost of BIOSANITIZER (10 grams, Rs 400/-) and the construction of a bin (Rs 600/-). It is interesting to know that this is the amount the municipal corporation spends per family in big cities in about 2 years, to transport garbage and dump it outside the expanding city limits, only to create pollution.
Several such BIOSANITIZER-based garbage-stabilization projects have been set up in Pune and other cities during the past 5 years. It is estimated that 300 urban buildings, 20 schools, 5 colleges, 5 temples, 8 hotels, 10 hospitals, 20 industries and 10 government institutions are successfully operating these projects. In fact, they have become mandatory for all new establishments now.
Q: What is the difference between the traditional and conventional composting techniques?
A: Traditional method uses cow manure (particularly, that from a desi cow) to stabilize the garbage. The manure used to go to the farmers’ field and then get used by the soil. This method achieved stabilization (stopping the CO2 evolution) by locking the nitrates. But the conventional method that is promoted by the agricultural scientists, involves adding more nitrates (or in general, the nitrogenous materials) to speed up the CO2 evolution and get a
stabilized product (compost) after the CO2 evolution stops. All the easily biodegradable carbohydrates(such as sugar, starch, cellulose, etc.) get wastefully bio-oxidised during such composting process, depriving the soil of her food and this also creates air pollution by producing CO2 and waste heat(Tate, 1995). Though the high temperature is appreciated as a pathogen-control mechanism, the compost can regrow the pathogens after it cools down. Some pathogens will easily survive in the cool boundary of the compost and serve as a culture. Compost thus is a biological ash, good for chemical agriculture. It is wrong to do a carbon-losing composting in organic agriculture.
Q: What is the drawback of biomethanation?
A: If the biogas is not collected and allowed to be wasted in the air, it is sheer polluting activity. However, even if the biogas is utilized as fuel, it still a wasteful activity because the process of producing the biogas is already consuming about half of organic food and produces CO2. Instead, if one uses garbage directly to grow more trees, one can get double the amount of fuel, without the risk of handling an explosive gas. Biogas is claimed to be a “clean” fuel, but this is far from the truth because its combustion still produces nitrogen oxides. Traditional firewood produces no harmful smoke, in fact that smoke is good for health. Irritating smoke is produced when we burn firewood that has nitrates!
Q: What are the obstacles in popularizing the garbage-fed urban gardens?
A: There is a lot of money involved in the current practices of collection, transport and dumping of garbage outside the city. So, any other method that suggests a decentralized solution tends to get neglected. However, with increasing fuel prices and awareness about organic food production, the decentralised terrace gardening using garbage will pick up.
Q: What about the sewage (organic wastewater)?
A: Western countries have solved the problem of organic garbage just by installing kitchen sink grinders that simply grind garbage and put it into the sewer. But this is no solution. One can use BIOSANITIZER to clean sewage and then use it for organic gardening. For treating 1 family’s sewage, one needs a 500 liters tank(of any suitable material), open or close and 10 grams of BIOSANITIZER(Rs 400/-) to start the system. The project gets commissioned within a day. One can do gardening even on rocky land because the treated sewage has all the organic nutrients.
Garbage is a resource, it has become a problem mainly because of its increasing nitrate contamination. These nitrates are coming from chemical farming. By conserving (locking) the nitrates and then using the garbage (and also sewage) for organic gardening, we can demonstrate how pollution can be prevented by using our neglected resources. Pollution, after all, is only a signal (warning) that we are wasting our resources. Man is after all a sensible (selfish) animal, we just have to teach him how to be selfish, not foolish. The act of dumping garbage outside the city and letting the sewage into rivers, lakes, sea, etc. amounts to foolishness.