A Farmer Centred Approach to Wastewater Treatment
and Resource Recovery

1. Introduction:

Indian agriculture had sustained its production with organic matter recycling methods over the past 60 centuries. The productivity, however, started reducing in this century, primarily due to environmental pollution, arising through burning of fossil fuels.  Farmers had to switch over to the use of chemical fertilisers (and pesticides) to sustain food production. The old method is referred to as organic farming whereas the new method is termed as chemical farming. The latter method, however, has now been found to be unsustainable due to its negative impact on the environment and increasing costs to the farmers as well as to the national economy. Scientists are now rediscovering the secrets of organic farming, with modern knowledge of soil biology and ecology. Vermiculture ecotechnology has been found to facilitate the conversion from chemical farming to organic farming without drop in the agricultural output. This paper discusses a farmer centred approach to wastewater treatment and resource recovery, to facilitate organic farming.

2. What is chemical farming? 

Chemical farming involves the use of chemical fertilisers and pesticides to increase the agricultural output, a method that was promoted during the past four decades to boost the food production.

The limiting nutrient of plants is carbon dioxide, next comes nitrogen and other nutrients. The output is controlled by the limiting nutrient, that is, by the availability of carbon dioxide. Modern greenhouses show spectacular results primarily due to increased supply of carbon dioxide. It should be noted that one needs to supply carbon dioxide in the plant vicinity, without polluting the whole atmosphere. The latter produces global warming that disturbs the climate and food production.

In chemical farming one has to use excessive amounts of nitrogenous fertilisers (such as urea or ammonium nitrate) to start the denitrifying reaction in the soil. This involves converting the nitrates back into nitrogen gas, quite a wasteful reaction for nature. This reaction also cracks the capital reserve of the soil organic matter and produces the carbon dioxide that increases food production. Obviously this cannot be a sustainable method because it exploits the soil's organic reserves created over the centuries. These reserves need to be maintained and built up because they give the soil its ability to hold moisture and nutrients. After a few decades of chemical farming, we have witnessed a drop in the soil fertility and hence reducing yields. Soil organic content has been depleted and even the response to the chemical fertilzers is poor nowadays.

In chemical farming, farm residues (such as straw) cannot be used to build up the soil organic matter. Uncomposted organics rob the nitrates and delay the denitrifying reaction necessary for the production of carbon dioxide. Hence farmers have to compost the organic residues first, even if they are well stabilized (they are non-polluting and are not in the stage of decomposition). Composting process burns 50-90 percent of organic matter wastefully, producing carbon dioxide that can pollute the atmosphere. Composting also produces leachate that pollutes the groundwater. Chemical farming cannot sustain without an input of compost, about 20 tons per hectare per year, a recommendation evolved out of research at the agricultural universities. Farmers cannot get the raw materials to produce this amount and hence, farmers neglected this aspect, only to lose the soil productivity. Such soils with depleted organic matter cannot hold moisture and nutrients and farmers have to spend more on irrigation and fertilizers. If irrigation or rain is in deficit, there is a crop failure.   

To promote the denitrification in the soil, chemical farming involves the use of excessive amount of inorganic nitrogen fertilisers, much more than the actual needs of the plants. This results in pollution of ground and surface water with nitrates, that have a negative impact on physical and mental health of humans and pet animals. Each year the farmer needs to increase fertiliser use to sustain output because soil develops its ability to denitrify more speedily. All beneficial soil life gets destroyed in the denitrification region.  The farmer has to spend more each year and the nation has to import more oil to produce these fertilisers. The Punjab farmers produced higher yields, no doubt, but got reducing profits each year.

Since more than required nitrogen is supplied, the plants get surplus nitrates in their sap. This has harmful effect on plant growth because each plant grows well only in a narrow bandwidth of soil nitrates. Other plant nutrients, such as phosphorous, potassium and other major and micronutrients, are required to counter the harmful effect of extra supply of nitrogen. Again, an extra cost to the farmers and to the nation as many of these need to be imported. There is also pollution of water bodies due to leaching of soluble nutrients.

Plants having surplus nitrates are unsuitable for human consumption. Nature has developed pests to attack such plants and check the food quality. Not knowing this, farmers were advised to use (spend for) pesticides that poisoned the whole ecology and only produced resistant pests, forcing farmers to use a stronger (more toxic) pesticide each year, adding to the burden on his pocket. Use of pesticides also resulted in the production of food polluted with pesticides and nitrates, both harmful for human consumption. Such plant produce also has more moisture, making the extra food production superfluous. This produce also has a poor shelf life due to the nitrate content. It is found that food spoilage due to fungi, insects or rodents is due to residual nitrates in food. These are nature's mechanisms to destroy the faulty food.

Apart from the extra input costs, one needs to use higher irrigation in chemical farming, just to adjust the nitrate level to the plant's required bandwidth. Increase in chemical farming has depleted (and polluted) our water resources.

Wastewater treatment needs to be planned differently for organic and chemical farming. In organic farming, free nitrates (nitrites and ammonia) need to be locked, while conserving the organic content because the latter is the base of organic farming. In chemical farming, however, organic matter in the wastewater needs to be biologically incinerated in the wastewater treatment plants, using electricity, which is often produced by techniques that are polluting. Current pollution control laws are formulated with chemical farming in mind. The treated wastewater, without the organic content (COD) and enriched with inorganics, is suitable only for the chemical farming, but highly harmful to the nature and natural organic farming. High inorganics to organics ratio, which is characteristic of the secondary treated wastewater, is ideal food for water hyacinth, mosquitoes and pathogens. It is found that while raw sewage may lead to the breeding of ordinary mosquitoes in the water bodies, the secondary treated sewage encourages breeding of malaria and dengue mosquitoes. It is also an ideal food for other pathogens. Allowing the secondary treated sewage and other wastewaters in the water bodies should not be permitted unless the inorganic content, too, is removed. This is very costly (called tertiary treatment), hence not practiced.

3. Eco-friendly Wastewater Treatment: 

We need to understand nature's requirements and treat wastes (solid wastes and wastewaters). Fish can utilise organic matter in water if the inorganic content is reduced. Use of cowdung in fisheries is a good example. Use of poultry manure (this has higher inorganic to organic ratio) leads to mosquito production after the fish get killed due to the nitrate toxicity. Human excreta and urine, too, has high inorganic content that is harmful to the environment.

The soil, too, needs the supply of organic matter, with minimal inorganic load. The soil life is managed by the earthworms that aerate the soil, maintain the pH and cull the harmful soil pathogens, encouraging the beneficial soil microorganisms that use organic matter and rock soil minerals, to produce the plant nutrients as per the plants' genuine needs. This leads to healthy plant production, without the need to use polluting agrochemicals.

Soil’s fertilizer factory, thus is managed by the earthworms that process the rock particles to produce the plant nutrients. The energy source is organic matter, available from dead roots and organic inputs to the soil (in the form of organic fertilizers). The earthworms, however, cannot tolerate salinity of soil and the water used for irrigation.. Hence wastewater needs to be processed to produce a high organic to salt ratio and only the toxic organic content needs to be removed. Use of BioSanitizer makes this an easy task.

4. BioSanitizer

This concept was developed by Dr Uday S. Bhawalkar of Bhawalkar Ecological Research Institute (BERI), Pune. It is based on the following concepts:

Wastes (solid or liquid, the latter being known as wastewaters) are actually resources if they are treated to become food for the ecology.

If toxic organics and inorganics are managed, nontoxic organics (sugars, starch, cellulose, etc.) are food for the ecology and need not be bioincinerated, as done in the conventional secondary treatment of wastewaters and in composting.

BioSanitizer is a catalyst produced from natural ingredients and is a simple tool to manage the toxic organics, and inorganics, converting the waste ingredients into resources. The action is known as biosanitization and controls the pathogens too, because the pathogens prefer inorganic and toxic organic pollution.

BioSanitizer can be used to biosanitize both the solid as well as liquid wastes, only the moisture content is different in these two catagories. Human excreta, if healthy, is produced as a solid waste. We pour costly and scarce drinking water to produce sewage. Sewage is conventionally treated to produce sewage sludge that needs to be treated as solid waste. Since the inorganic load of sewage sludge is high, wooden chips are mixed to start composting reaction. Carbon dioxide is produced in the stages of electricity generation, secondary sewage treatment and in composting. This is equivalent to loss of resource (organic matter). Environmental pollution takes place only when we waste a resource.

BioSanitizer locks the inorganic content of the wastes and cracks the toxic organics to produce safe organics, retaining food organics during this treatment. The locked inorganics become safe for the aquatic life and the soil. These also become a resource in healthy soil (with earthworms). Plants can derive nutrition from the locked inorganics in healthy soil. To produce healthy soil, one just has to feed the soil with wastes that have been biosanitized with BioSanitizer

BioSanitizer harnesses interesting natural mechanisms to convert wastes into resources. These were learnt after reading the "books of nature" over the past forty years.

5. Using BioSanitizer:

Solid wastes or wastewaters can be stabilized in two ways:

By bioincinerating the simple organics, to stop the decomposition reaction (production of carbon dioxide), or

By locking the inorganics. This also stops the carbon dioxide production and produces stabilized wastes.

BioSanitizer uses the latter method that conserves the resources totally.

To stabilize solid wastes, one can add 1 gram BioSanitizer per 10 tons of waste. BioSanitizer is added in the top layer and the mass sprinkled with water, to produce stabilized waste in 10 days. This is the time for mixing, not the reaction time. The reaction is quite fast, over within a few minutes. One can reduce the mixing time with the use of mechanical mixing methods, if necessary.

To treat wastewater, one can add 1 gram BioSanitizer to the wastewater stream of 10 m³/day. BioSanitizer is added at the beginning of the sewer line or open nalla carrying wastewater, or in the first tank of the wastewater treatment unit. BioSanitizer locks the inorganics, cracks the toxic organics and also produces active oxygen that takes care of BOD and pathogens. A minimal treatment time, of few hours, depending upon the level of pollution, is required. Since no mechanical aeration or mixing is required for BioSanitizer action, this method is best used for "on-line" treatment while the wastewater flows in the underground or open channels. It is also useful for treatment of polluted lakes, rivers and wells/borewells. 1 gram is a good dose for a well/borewell and one gets results within few hours. Brackish water becomes sweet and one also gets free of pathogens, toxic organics and heavy metals..

6. Success Achieved:

BioSanitizer has been used successfully to clean the Powai Lake in Mumbai and Pashan lake in Pune. BioSanitizer has shown efficacy to clean the Ambil nalla in Pune. This carries sewage and pours it into the Mutha River. BioSanitizer also has been used in the sewers in Pune. Several individuals and industries have used BioSanitizer in their septic tanks to get water that is an asset for their gardens. Several industries have stopped mechanical aeration in their activated sludge plants and have found that BioSanitizer generates no sludge for disposal. The wastewater treatment plants require no machinery, electricity and operators. Several farmers have used BioSanitizer to treat their wells/bore wells to manage the inorganic pollution. and by cities and industries to treat wastewaters in eco-friendly manner. These methods are also easy to operate and maintain because BioSanitizer has auto-control action. The treated water becomes an asset for the soil.

7. Conclusion: 

BioSanitizer makes wastewater treatment a simple task. It converts pollution into an asset. The method pays for itself in a short time because of value-addition to the wastes. Capital investment is low and there are no recurring expenses. People accept it readily during the period of ongoing recession. It also makes sense ecologically.

Dr. Uday S. Bhawalkar