1. Introduction Domestic sewage is one of the major wastes disposed every day. It is99.
9% pure water by weight, rest of the 0.1% contains variety of dissolved andsuspended impurities which causes significant problems and also containsdisease causing microbes 1. Most of the communicable diseases are due tounsafe water, most of which is contaminated either by sewage or agriculturalrun-off. At Govardhan Eco Village (GEV), the domestic sewage waste is treated bySoil Biotechnology Method. SBT consists of impermeable containment and incorporates soil,formulated granular filter media and a select culture of organisms such asearthworms and plants. It involves a combination of physical and biologicalprocess for processing of waste water and it derives its fundamental principlefrom the functioning of a terrestrial ecosystem. It is a naturalbio-geochemical cycle of nature and hence proves to be most effectiveeco-friendly technology for waste water treatment.
The SBT plant at GovardhanEco Village recycles 30,000 liters of sewage every day 2. Chemical and Microbial analysis of domestic sewage water is donebefore and after treatment to prove the benefits of this eco-friendlytechnology. 2. Parameters analyzedFollowing water quality parameters were analyzed to assess the waterpollution status: (1) pH (2) Total dissolved solid (TDS) (3) Total SuspendedSolids (TSS) (4) Dissolved oxygen (DO) (5) Chemical oxygen demand (COD) (6)Biochemical oxygen demand (BOD) (7) Total Kjeldhal Nitrogen (8) Oil and Grease(9) Detection of sodium, potassium, Nickel, Copper and Aluminum by AAS (10) Enumerationof total viable bacteria, coliforms, psychrophiles and thermophiles (11)Detection of fungi and actinomycetes. 3. Water quality parameters and their effects on agricultureThe water was collected from GEV, Palghar district in order to studyphysico-chemical and microbial characteristic of domestic sewage water pre- andpost treatment. The samples were collected following the standard methodsdescribed for sampling.
The standard methods and procedures were used for qualitativeand quantitative estimation of water quality parameters. 3.1 pH: pH is the measure of the acidity or alkalinity of a solution. WaterpH between 6.5 and 8.
5 is considered to be the advantageous for irrigation. pHvalues above and below the normal range, indicates that action needs to betaken to get better crop performance3. 3.2 COD: Chemicaloxygen demand is a measure of the amount of oxygen necessary for the chemicaloxidation of organic matter.
It can be high without any negative effects forthe plants and the soil. In some cases high organic matter content isconsidered positive as it improves the water holding capacity of the soil onthe long term. 3.3 BOD: Biological oxygen demand is a measure of the amount of oxygenrequired for the biological oxidation of organic matter.
It can be used as ameasure to find out the efficiency of waste water treatment plants. 3.4 TSS: Total suspended solids arethe dry-weight of particles blocked by a filter 4. TSS, measured in mg/l, can becalculated as 3.5 TDS: “Total dissolved solids”refer to any minerals, salts, metals, cations or anions dissolved in water.
It comprises of inorganic salts andsome minute amounts of organic matter that are dissolved in water 5, 6. 3.6 Total kjeldhalnitrogen: The nitrogen cycle is the means by whichatmospheric nitrogen is made available in different forms to living organisms.From the basic molecules of ammonia, nitrate and nitrite to the more complexamino acids and proteins, nitrogen is essential for living organisms tofunction. It is an important part in the smooth operation of many wastewatertreatment plants 7, 8. 3.
7 OIL AND GREASE: Oil and grease is organic toxic waste which causes ecology damagesfor aquatic organisms, plant, animal, and is mutagenic and carcinogenic forhuman being. They form a layer on water surface that decreases dissolved oxygen9. 3.8 Aluminum: Can cause non-productivity in acid soils (pH < 5.5), but morealkaline soils at pH > 7.0 will precipitate the ion and eliminate anytoxicity 10,11. 3.
9 Nickel: Toxic to most of the plants ranging 0.5 mg/l – 1.0 mg/l. Toxicitycan be reduced at neutral or alkaline pH 10. 3.
10 Copper: Toxic to most of the plants ranging 0.1 to 1.0 mg/l in nutrientsolutions. Copper can cause leaf chlorosis as well as the suppression of rootgrowth 10,11. 3.11 Sodium: Sodium exists in almost all irrigation water and is not essentiallya cause for concern unless high concentrations are present.
High concentrations(> 70 mg/L) can be dangerous to both plants and soils. Sodium in irrigationwater can be absorbed by roots and flora, and foliar burning can occur if excessamounts accumulate in leaf tissue 12. 3.
12 Potassium: The potassium (K+) cation behaves similarly to sodium inthe soil and is commonly found in natural waters in small amounts. 3.13 Microbiological analysis:Since the composition of wastewater varies, thetypes and numbers of organisms will fluctuate. Fungi, protozoa, algae, bacteriaand viruses are present.
Raw sewage may contain millions of bacteria permilliliter including the coliforms, streptococci, anaerobic spore-formingbacilli, the proteus group and other types originating in the intestinal tractof humans. The causative agents of poliomyelitis, hepatitis, typhoid, dysenteryand cholera may occur in sewage. Certain bacteriophages are readily isolatedfrom sewage.
The potential methane producers such as Methanococcus, Methanobacterium, Methano-sarcina contribute to theproduction of anaerobic and temperature elevated conditions in sewage13.Bacterial growth is sensitive to temperature because high temperature canincrease the fluidity of the phospholipid bilayer which leads to cell lysis.However, bacteria are known to have higher enzymatic activity at highertemperature because of increased thermal energy. For example, when thermophilicsludge treatment is compared to mesophilic treatment, the sludge biodegradabilityis higher with thermophilic degradation 14.
3.13.1 Total viable countIn routine analysis the total number of bacteria present in 1 ml ofsewage is determined by standard plate count method.
One set of plates isincubated at 370 C for 48 h (mesophilic bacteria). Another set ofplates is incubated at 220 C for 72 h (psychrophilic bacteria) andyet another set of plate is incubated at 550C for 72 h (thermophilicbacteria). After incubation the colonies are counted and the amount of cfu/ml(colony forming units) can be calculated 15.Plate count technique is useful in determining the efficiency ofoperation for removing or destroying organisms. A microbial count can be madebefore and after a specific treatment and results obtained indicate the degreeto which the bacterial population has been reduced.
A water sample containingless than 100 bacteria per ml is considered to be safe 5. The total number ofpsychrophilic bacteriaNon pathogenic bacteria grow mainly at lower temperatures. It isimportant that Gram-negative bacteria in water produce lipopolysaccharides intheir cell wall which can be toxic – like endotoxins of pathogenic bacteria.Because of this, their numbers in water should be constantly monitored. A largeincrease in their numbers is evidence of the presence of easily availableorganic compounds in the water. Theoretically, the presence of 0.1 mg organiccarbon in water can result in an increase of bacteria up to 108 cfuin 1 ml.
Phosphorus is also a factor which stimulates the growth ofpsychrophilic microorganisms. Adding even small amounts of this element (i.e.,50mg/l)causes 10 times the acceleration of bacterial growth in a water treatment plant15.
The total number ofmesophilic bacteriaMore dangerous are high numbers of bacteria growing at 370C,because among this high population, pathogenic forms may be found which aredangerous for human health. High number of bacteria in samples of water canprove that water treatment processes proceed badly or that polluted water issiphoned15. The total number of thermophilicbacteriaIt is an index of production of gases such as methane that elevatethe temperature of sewage and allow the proliferation of thermophilic bacteria14. 3.13.2 Total coliform andfecal coliform (MPN – Most probable number)It is statistical method based on the probability theory.
In thistechnique, the sample is serially diluted till the numbers of organisms reachthe point of extension. From each of these dilutions several multiple tubes ofa specific medium are inoculated. Presence of organism is indicated by acid andgas in the medium. Pattern of positive and negative test results are then usedto estimate the number of coliforms in the original sample. Since the testgives the most probable number of organisms present in the sample. it is alsoknown as MPN test16. 3.
13.3 Study of biologicalnitrogen fixersAzotobacter is a free living, non symbiotic nitrogen fixingbacterium that brings about biological nitrogen fixation 17. Since the sewageis SBT treated it is possible that these valuable microorganisms may enter thetreated sewage by diffusion from the soil.
Enrichment technique is used toincrease the number of this organism as its number is very few in soil samplesand hence in the treated sewage. 4. Materials and methods:4.
1 pH: pH was determined by pH metry using a pH meter18. 4.2 COD: 50.1N Pottasium dichromate, 0.1M sodium thiosulphate, 2M sulphuricacid, 1% starch solution. COD was determined by titrimetry by using procedureusing Aneja.
4.3 BOD: 50.5% Allyl thiourea, 1N sulphuricacid, sodium hydroxide. BOD was determined by titrimetry by using procedureusing Aneja. 4.4 TSS: APHA 2540 D TotalSuspended Solids Dried at 103–105°C 19.
4.5 Oil and grease: American Public Health Association (APHA)5520 B. Partition-Gravimetric Method 20. 4.6 Microbiologicalanalysis:Raw and treated sewage effluent samples were incubated overnight at370C, before analysis.The samples were sampled to enumerate total viable counts and totalcoliform counts.
Also, the fungi and actinomycetes present in the samples werestudied. The sample was also checked for the presence of nitrogen fixingbacteria, Azotobacter spp.The samples were 10-fold serially diluted and the total viable countwas carried out using appropriate dilutions, sterile molten nutrient agarmedium and incubation conditions by pour plate method15. Determination oftotal coliform count was carried out by MPN (three tube method) using singleand double strength Lauryl tryptose broth16.For the study of fungi and actinomycetes, a loopful of each of thesamples were streak isolated on sterile Sabouraud’s dextrose agar and sterileKenkunight and munnair’s agar plates respectively5.
Azotobacter spp was isolated by enrichment in Sterile Ashby’smannitol broth medium and subsequent streaking on sterile Ashby’s mannitol agarplates5.