Distillery Spent Wash, an Ameliorant for Domestic Waste Composting and Vermicomposting

By Rajendran Palaniswami¹*, M. Anandhakumar² and N. Nagarajan³
April 2011

The Authors are Associate Professor and Research Head¹*, M.Phil² and Research Scholars³ at the Department of Applied Zoology and Biotechnology, Vivekananda College, in Tiruvedakam West, Madurai, Tamil Nadu, India.   * Corresponding Author

Abstract
Rampant use of chemical fertilizers contributes largely to soil degradation and adversely impacted agricultural productivity deteriorating the environment. The lack of sustainability in production in recent years is becoming a major concern. Proper management of waste can produce good quality organic manure which can act as soil conditioners. The organic wastes generated due to domestic activities contain decomposable substances that can form substrates to produce organic manure by composting and Vermicomposting. Spent wash produced from distillery industries is rich in organic material and characteristically less toxic and easily amenable for microorganisms. An attempt is made to use the spent wash as an ameliorant to enhance the organic manure form kitchen wastes using composting and Vermicomposting. Bioassay study results of cowpea plant (Vigna unguiculata) has proved the productive character of distillery spent wash as an ameliorant for composting and Vermicomposting. The present result also advocates a new eco-friendly, economical and environmentally safe strategy to utilize the distillery effluent for producing valuable organic fertilizer that reduces environmental hazards to meet the needs of the agriculturalists and the industrialists.

Introduction

One of the most conspicuous features of the modern consumerist’s society is the generation of massive quantities of waste. This is both costly and difficult to dispose off through conventional methods. Environmental degradation due to the indiscriminate use of modern agricultural techniques such as the use of synthetic fertilizers is a major threat confronting the world. It leads to loss of soil fertility due to imbalanced use of fertilizers that has adversely impacted agricultural productivity and causes soil degradation. Now there is a growing realization that the adoption of ecological and sustainable farming practices can only reverse the declining trend in the global productivity and environment protection (Wani and Lee, 1992; Wani et al., 1995). Anitha et al. (2004) reported that 500 g of biodegradable kitchen waste is generated per day in a family consisting of four members. Among 3,000 million tones of organic wastes annually produced in India, 60 % constitutes biodegradable kitchen waste (3,000 tones) and it can be utilized for important resources like fertilizer using vermitechnology, the versatile technique that yields organic fertilizer using earthworms (Vig and Kanur, 2005).

India is a major producer of sugar in the world and sugar industry offers employment potential and contributes substantially to economic development. There are about 579 sugar mills and 285 distilleries in India. The alcohol industry produces a huge amount of wastes every day, which is rich in organic material and characteristically less toxic and easily amenable for microorganisms. Alcohol is produced in India by the fermentation of molasses. The mother liquor left after the sugar production is spent wash. It is dark brown in colour, with high temperature, low pH and high ash content (Chauhan and Dikshit, 2006). The distillery spent wash do not contain any toxic compound, but rich in plant nutrients, organic carbon and proteinaceous substances. Therefore, it could be safely used for composting or co-composting of organic/biological wastes (Ramasamy et al., 2007). The constituents of the distillery effluents are plant organic matter, dead yeast cells, and salts of K, Ca, Mg, etc., which the sugarcane plant has absorbed from the soils and are not having the hazardous chemicals. Advocating its application to the soil for agriculture is highly beneficial. Agricultural usages of these effluents are the safest and cheapest disposal for a safer environment (Soundarrajan et al., 2007).

Ten to fifteen liters of molasses spent wash is generated during one–liter ethanol production. Thus, more than 30 billion liters of molasses spent wash is generated annually by 254 cane molasses based distillery in India alone (Kumar et al., 1998). There is an increasing interest in the agricultural use of industrial wastes because of the possibility of recycling valuable components such as organic matter, nitrogen (N), phosphors (P), potassium (K) and other nutrients and their suitability for land application (Ramasamy et al., 2007).

The waste generated form the industry can be remediated using composting and vermitechnology, a novel technique meant for waste utilization. India being agriculture based country, it could easily produce millions of tones of Vermicompost and considerably reduce the use of chemical fertilizers. (Rajendran et al., 2008). The current paper reveals the advantages of utilizing domestic and distillery industrial wastes combining with conventional composing process and vermitechnology. Attempt is made to use distillery spent wash as an ameliorant for conventional composting processes. The macro and micronutrient content of compost and vermicompost is analyzed and the results are discussed.

Materials and Methods

Distilleries spent wash for the study was collected from Dharani Sugars & Chemicals Pvt. Ltd., situated at Naranapuram village of Sivagiri Taluk in Tirunelveli District, Tamil nadu, India. The physico-chemical characters were analyzed in factory lab. Kitchen wastes from Vivekananda college mess and earthworm species, Eisenia foetida from college vermifarm were procured for composting and vermicomposting studies respectively. Four pre-compost pits (60cm × 60cm × 30cm) were prepared for the experimental trials as follows:

Pit-1 ► Domestic Waste (5 kg)
Pit-2 ► Domestic Waste (5 kg) + Spent Wash (3 L)
Pit-3 ► Domestic Waste (5 kg) + Cow Dung (3 kg)
Pit 4 ► Domestic Waste (5 kg) + Cow Dung (3 kg) + Spent Wash (3 L)

The domestic waste was made into small pieces and dumped into pits as per the above said combinations. The pits provided optimal conditions for composting. Limited aeration, temperature and water were provided throughout the process (45 Days). Water was frequently sprayed into the pit to maintain moisture. After the composting process, digested material was used for vermicomposting. The macro (Nitrogen, Phosphorous and Potassium) and micronutrient (Iron, Manganese, Zinc and Copper) contents of pre-digested compost and vermicompost were analyzed at soil testing centre, Tamil Nadu Agriculture Department, Madurai following the methods explained by Tandon (1993). Phosphate in soil is determined by Olsen’s method (Olsen et al., 1954) for neutral-alkaline soils and Bray and Kuurtz P1 method (Bray and Kurtz, 1945) for acid soils.

Table 1 · Physico chemical characters of Distillery spent wash
Component of Spent wash Spent wash (%)
Carbon33.0
Hydrogen2.65
Sulphur0.75
Nitrogen1.28
Oxygen22.2
Ash39.1
Table 2 · Microbial population (CFU) in compost and vermicompost
Experimental trails Compost (CFU) Vermicompost
(CFU)
Domestic waste1 × 1073 × 107
Domestic waste + Spent wash2 × 1075 × 107
Domestic waste + Cow dung3 × 1077 × 107
Domestic waste + Cow dung + Spent wash6 × 1071 × 109
CFU = Colony Forming Units
Experimental Trials:
Pit-1 : Domestic Waste
Pit-2 : Domestic Waste + Spent Wash
Pit-3 : Domestic Waste + Cow Dung
Pit 4 : Domestic Waste + Cow Dung + Spent Wash
Figure 1 · Macronutrient variation percentage (%) in
Compost and Vermicompost, in different experimental trials
Fig 1
Figure 2 · Micronutrient variation percentage (%) in
Compost and Vermicompost, in different experimental trials
Fig 2
Figure 3 · Vigor index of Vigna unguiculata seeds grown
in vermiwash prepared from different experimental trials
Fig 3
Figure 4 · Root length of Vigna unguiculata grown in
different experimental trials at various growth durations
Fig 4
Figure 5 · Shoot length of Vigna unguiculata grown in
different experimental trials at various growth durations
Fig 5
Figure 6 · Biomass of Vigna unguiculata grown in
different experimental trials at various growth durations
Fig 6
Figure 7 · Chlorophyll of Vigna unguiculata grown in
different experimental trials at various growth durations
Fig 7

Pre-digested domestic wastes (experimental trials and control) were transferred to four different plastic troughs for the introduction of earthworms for vermicomposting. Suitable control was also maintained. Fifty earthworms (Eiseniafoetida) were introduced into each plastic trough and allowed for vermicomposting. Frequent water spraying was done to maintain moisture till the completion of the process (20 - 30 days). Lourduraj and Yadav (2005) method was followed for the collection of vermiwash. The liquid extraction was being collected in a container and used for vigor index studies. Microbial populations of the predigested compost and vermicompost were carried out following serial dilution technique (Kannan, 1996) and denoted in terms of colony forming units (CFU).

Certified Vigna unguiculta (Cowpea) seeds were used for vigour index and other bioassay studies. Vermicompost prepared form experimental trials were used for morphometry (root and shoot length), gravimetry (plant dry weight) and chlorophyll estimation. Vigour index was performed by following the procedures of Abdul Baki and Anderson (1973). Ten seeds were placed over the vermiwash soaked cotton and watering was done regularly. Triplicates with control were maintained throughout the experiment. The Petri plates were kept at indoor laboratory conditions under diffused light. Germination counts were taken after 5 days. The shoot and root lengths were measured (cm) after 10 days. The morphometric and gravimetric studies of root and shoot were carried out with the seeds grown on different vermiwash collections. Plant height was measured from the ground level up to the tip of the plant. The shoot / root length were measured from the grown shoot / root to tip of the longest / shoot / root and expressed in cm. The plant samples collected were initially air dried and later oven dried at 60° ± 5° C. The dried materials were weighed and expressed as g / plant.

Results

The physico-chemical characters of the spent wash samples are shown in Table 1. The spent wash is acidic (pH 3.5) and loaded with high carbon content (33%). This being plant origin, it contains considerable amount of plant nutrients and the nitrogen content is 1.28%. The microbiological characters of the compost and vermicompost prepared using different experimental trials show variation (Table 2) in colony farming units (CFU). Increase in microbial count is observed in all the experimental vermicompost samples compared to the conventional bio-compost. The colony farming units observed is higher in the samples collected from pit 4 and lower in pit 1. The pit that contained domestic waste alone is treated as control.

The micro and macro nutrients of experimental trial pits (domestic waste+ cow dung, domestic waste+ spent wash and domestic waste+ cow dung+ spent wash) are compared with control (domestic waste alone). The variations in nutrient content compared to the control are given in percentage (Fig 1 and 2). The changes observed in the experimental trial pits are mainly due to the presence of cow dung and spent wash. Nitrogen and phosphorous content of vermicompost in control and experimental trial pits showed increase compared to their respective bioscompost (Fig 1). However the potassium content showed decline in Pit 4 and 2. The nitrogen content of vermicompost in the experimental Pit 4 showed increase compared to the control. Phosphorous content in all the pits showed decline except in the compost from pit 4. Potassium level showed decrease in all the experimental trial pits except pit 3. Micronutrient variation of experimental trial pits compared to the control is represented (in terms of %) in Fig 2. In compost and vermicompost of the experimental trials raise in iron content is observed compared to the control. Much variation is not observed in manganese content. Elevated zinc content is noticed in vermicompost and compost of Pit -3 and 4 elevated copper level is observed in Vermicompost. However in other pits much variation is not observed.

Vigour index of Vigna unguiculata grown in vermiwash collected from the control and experimental trials are represented in Fig 3. The experimental trial results indicate an increase in vigour index in all the pits compared to the control that contained only tape water. Root length of cowpea plant grown with vermicompost prepared from experimental trials is represented in Fig 4. Significant increase is observed in the root lengths of the plants that were grown for different durations in the vermicompost prepared by experimental trials. Shoot length of cowpea plant grown with Vermicompost prepared from the experimental trials are represented in Fig 5. Significant increase is noticed in the shoot length of all the plants that were grown for different durations. Shoot length of plants that were grown for 30 and 40 days duration is prominent compared to 10 day plant. Biomass of cowpea grown for different durations is represented in Fig. 6. Uniform increase in all the plants is observed in proportion to growth duration. However prominent biomass increase is observed in the plants that were grown for fourty days. Chlorophyll content of cowpea grown for different duration with vermicompost prepared using different experimental trial is shown in Fig 7. Uniform increase in chlorophyll content compared to control is seen in all the plants grown with vermicompost prepared by experimental trials. Chlorophyll content shows proportionate raise in relation to the duration of growth. Maximum chlorophyll level is seen in the plants that were grown for fourty days. However ten and thirty day’s plants shows minimum and intermediate chlorophyll level compared to the fourty day’s plant.

Discussion

The physico-chemical character of the spent wash sample collected from the distillery industry is loaded with high carbon content since it is plant origin. The distillery of effluent contains fairly high amounts of plant nutrients viz., N, P, K, Ca, Mg, S and appreciable amounts of micronutrients, which the sugarcane crop has absorbed from the soil as well as organic matters (absorbed from atmosphere). The available K status of the soil increased to the tune of two to three times from the initial soil test value in spite of the crop removal, which might be due to the higher K contents of the effluent (Soundarrajan et al., 2007).

The microbiological characters of vermicompost prepared using different experimental trials compared to compost shows more microbes. The result coincides with the study of James (1991) indicating microbial biomass in the worm cast was found to be high and their activity was essential for release of nutrients into the medium so as to be taken by the plants. The gut of the earthworms act as a bioreactor providing ideal conditions like temperature, pH and oxygen concentration for speedy growth of useful aerobic bacteria and actinomycetes thus resulting in the microbial density about 1000 times greater than in the surrounding soil (Sajnanath and Sushama, 2004).

Macro and micronutrients of vermicompost from experimental and control trials are more compared to conventional bio compost. Earthworms are able to convert wastes into fine mucus coated fecal pellets, popularly known as vermicompost. This is a quality organic manure rich in beneficial micro flora and plant promoter substances along with major and micro nutrients necessary for plant growth, in water soluble form so that they are immediately available for plant use (Bhawalkar and Bhawalkar, 1992). Enhanced nutrients (N, P, K, S, Ca, Mg, Mn, Fe, Zn) in the case vermicast, compared to the surrounding soil was shown to be due to mineralization taking place in the gut as well as in the casts (Parthasarathi and Ranganathan, 1999).

Increase in nitrogen and phosphorous content of vermicompost in control and experimental trial pits compared to their respective bio-compost help to increase the growth of plants. Available N, P and K content, gradual increases in the available nutrients at different growth stages had significantly increased post harvest soil compared in initial soil and control (Soundarrajan et.al 2007). The decrease in potassium content in the present study is in accordance with the results of Orazco et al., 1996. Their investigation reveals the effect of earthworm on decomposition of coffee pulp increases available phosphorous, calcium, Mg and decrease in K. Lumbricids in a pasture soil produced casts that contained 73% of the nitrogen found in the ingested litter, indicating both the importance of earthworms in incorporating litter nitrogen into the soil and the inefficiency of nitrogen digestion by earthworms (Syers et al., 1979). The available nitrogen in the soil increased significantly with increasing levels of vermicompost and highest nitrogen uptake was obtained at 50% of the recommended fertilizer rate plus 10 e ha-1 vermicompost. Similarly the uptake of nitrogen, phosphorous, potassium and magnesium by rice (oryza sativa) plant was highest when fertilizer was applied in combination with vermicompost (Jadav et al., 1997). The bio-waste recycling studies of Sajnanath and Sushama (2004) using Eisenia fetida reveals in vermicompost the iron content increased 1.5 times, while all other elements decreased. The present study result also shows a raise in iron content in vermicompost compared to the control.

Increase in vigour index of Vigna unguiculata grown in vermiwash collected from the control and experimental trials is due to the presence of rich microflora, several enzymes (auxins), and complex growth regulators like gibberlins (Kumar mall et al ., 2005). Experiments at Tennessee Technological University found that 10% vermicompost in a potting mix improved the germination of the seeds of low viability (Echinacea purpurea) by 43%. Nagavallemma et al., (2006) reported vermicompost has growth promoting hormones and proved its activity using maize (Zea maize). The plant growth hormones in vermicompost prepared by experimental trials might be the reason for the significant increase in the root and shoots lengths of the plants that were grown for different durations. The result is also in accordance with the studies of Vijaya and Aliya (2005) in the tree species Albizia lebbeck. The study reveals increased shoot length and dry biomass in the trees that were grown with vermicompost.

Vermicompost plays a major role in improving growth and yield of different field crops, vegetables, flower and fruit crops. The application of Vermicompost gave higher germination (93%) of mung bean (Vigna radiate) compared to control (84%). Further, the growth and yield of mung bean was also significantly higher with vermicompost application. The fresh and dry matter yield of cowpea (Vigna unguiculata) were higher when soil was amended with Vermicompost than with bio digested slurry (Karmegam and Daniel 2000). Biomass of cowpea grown for different durations in the present study with vermicompost showing uniform increase in proportion to growth duration coincides with the above results.

Uniform increase in chlorophyll content compared to control seen in all the plants grown for different durations may be due to the vermicompost prepared by different experimental trials. The chlorophyll content studies of Prabhakar et al. (2006) in Cicer aeritenum grown with fertilizer factory effluent for different durations reveal a significant increase which may be due to the presence of lower concentration of effluents. Chlorophyll content of cowpea grown for different duration with vermicompost prepared using different experimental trial. Chlorophyll content shows proportionate raise in relation to the duration of growth. Maximum chlorophyll level is seen in the plants that were grown for fourty days. However ten and thirty day’s plants shows minimum and intermediate chlorophyll level compared to the fourty day’s plant.

Conclusion

Earthworms are the natural fertilizer factories which serve as bio-catalytic agents to enhance the soil fertility through physical chemical and biological processes. Earthworms can be called as biological indicators of soil fertility because soil with earthworms supports the healthy population of a variety of organization essential for maintaining a healthy soil. (Khan, 2008). Recycling of agro-industrial wastes using earthworms has become an important component of sustainable agriculture which has a multidirectional impact in terms of safe disposal of wastes, preventing environmental pollution besides providing nutrient rich materials. The vermicompost produced form the above procedure can replace the chemical fertilizer and pave the way for the utilization of large quantities of distillery spent wash and domestic wastes.

References

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