Greywater is the wastewater generated in the bathroom, laundry and kitchen. Greywater is therefore the component of domestic wastewater, which has not originated from the toilet or urinal. The greywater generation in NEERI is presented in Table 4.33
4.5 Physico-chemical Properties of Water and Wastewater
The water and wastewater samples were collected from different point of sources in NEERI campus & colony and analyzed for determines of physico-chemical and bacteriological properties as shown.
4.6 Percent Greywater Generation and Water Losses of Total Water Supply in NEERI
In NEERI, total municipal water supply is 733333 L/D and total water consumption is 521633.876 L/D. Thus, water loss is 211699.1 L/D. These losses are due to the leakage in taps, urinals, pipe bursting, construction purposes, etc. The total greywater generation is 12.871% of total water consumption in NEERI and greywater % composions shown in Table.4.35.
Total Water Supply in NEERI = 733333 (L/D)
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Total Water Consumption = 521633.88 (L/D)
Percent Water Consumption = 71.13%
Water Losses of Total Water Supply = 211699.1 (L/D)
Percent Water Losses = 28.869 (%)
4.7 Water consumption in liter per capita per day (Lpcd)
Water Consumption in Colony East and West, RSH & Guest House = 216703.9 (L/D)
Total No. of Person in NEERI Colony Approximately = 1000 P
Water Consumption in Liter /Capita / Day = 216.07 (Lpcd)
4.35 Composions of Greywater in Quarter No.D6 of D-Block, NEERI Colony
4.8 Percentage of water requirements and wastewater distribution in Quarter No. D-6 of D-Block, NEERI Colony; Percentage of water requirements and wastewater distribution show in under following graphs:
4.8.1 Characteristics of Household Greywater in Quarter No.D-6 of D-Block, NEERI Colony
There is variation in chemical and microbiological quality of greywater depending on source type. A typical qualitative composition of greywater for bathing, cloths washing and wash basin (it excludes kitchen wastewater) are:
[i] Cloth Washing
Foam, high pH, nitrate, oil, and grease, oxygen demand, phosphate, salinity, soaps, sodium, suspended solids, turbidity.
[ii] Bathing Shower
It contains bacteria, hair, odour, oil and grease, oxygen demand, soaps, detergents, suspended solids and turbidity etc.
[iii] Wash Basins
It is used for washing of teeths, mouth, hand and saving etc. toothpaste contains in general sodium monofluoro, phosphate, silica sorbital, triclosan, calcium corbonate, siodium chloride and hair during savings, soaps, bacteria, during mouth and hand washing.
There is variation in chemical and microbiological quality of greywater depending on source type. A typical qualitative composition of greywater and chemical characteristics of greywater quality are presented in Table 4.38. Treatments requirements vary based on chemical characteristics and intended use of treated greywater.
The microbiological quality in terms of number of thermotolerant coliforms of greywater form various sources are presented in Table 4.39. Thermotolerant coliforms are also known as faecal coliforms (expressed as colony forming units per 100 ml) and are a type of micro-organisms which typically grow in the intestine of warm blooded animals (including humans) and are shed in millions to billions per gram of their faeces. A high faecal coliform count is undesirable and indicates a greater chance of human illness and infection developing through contact with the wastewater. Typical levels of thermo tolerant coliforms found in raw greywater sewages are in the order of 29X102 to 57X102 cfu/100 ml.
4.8.2 Performance Evaluation of the GTP in Q. No.D6 of D-Block, NEERI Colony
The performances evaluation of greywater treatment plant were investigated for these samples of greywater at steady state conditions and the average value data are summarized in Table 4.36. The average organic load in greywater found after pre-filtration 227.68 and after treated greywater 46.92 mg COD/lit, the solids in treated greywater were found to have about 156 mg/L dissolved and 29 mg/L suspended particles. From Table 4.38, all the parameters found in greywater were reduced and found better performance of the greywater treatment plant. The average 80 % COD and BOD 82 % of organic load was removed and TSS 74 %, TDS 55 %, Hardness 14 %, TKN 30 % and Turbidity 75 % were found to be adsorbed by the natural adsorbents used in filtration. Bacteriological characteristics of greywater summarized in Table 4.37, heavy metals summarized in Table 4.39 and greywater comparisons of water requirement and greywater generation Indian households and Quarter No.D-6 in D-Block, NEERI Colony summarized in Table 4.40. The traces of potassium, fluoride, Sulphate and calcium were found and removed fully from greywater. Greywater generation (L/D) from all blocks of NEERI Colony and Treated greywater parameters and their % Removal efficiency shown in fig.4.3-4.4
4.8.3 Typical Values of Greywater Quality Results in Quarter No.D-6 of D-Block, NEERI Colony
Always on Time
Marked to Standard
The purpose of the greywater quality tests was to identify the contaminants in greywater, their concentration and the possible adverse effects associated with greywater reuse. The greywater quality parameters were assessed according to the EPA recommended limits in the existing greywater (wastewater) guidelines. A summary of the major greywater quality parameters showing ranges of typical values is presented in Table 4.38.
188.8.131.52 Greywater Generation
Number of person staying in Quarter No.D-6 = 4
Greywater generated from bath, laundry & wash basins.
Number of observation = 21
Minimum value = 225 lit/day (56.25 Lpcd)
Maximum value = 400 lit/day (100 Lpcd)
Mean value = 316 lit/day (79 Lpcd)
Standard deviation = 11.43 Lpcd
184.108.40.206 Greywater Reused for Toilet Flushing (Indoor)
Number of observation = 27
Minimum value = 65.60 lit/day (16.40 Llpcd)
Maximum value = 120 lit/day (30 Lpcd)
Mean value = 98 lit/day (24.50 Lpcd)
Standard deviation = 3.71 Lpcd
220.127.116.11 Greywater Reused for Gardening/Irrigation (Outdoor)
Greywater reused before and after treatment for irrigation = 92 lit/day + 93 lit/day = 185 lit/day = 46 Lpcd
Raw greywater about 93 litre daily is used for watering vegetables seed plants viz. Onion, Tomato, Brinjal for replantation and Spinach, to see the impact of greywater on it. The goal of this study is to reuse of greywater for gardening/irrigation, washing purpose and toilet flushing.
Following are the results and analysis of greywater generated and reused for gardening/irrigation and future planning for water conservation in NEERI Colony.
Greywater generated in Quarter No.D-6 of NEERI Colony = 79 Lpcd x 4 person = 316 lit/day and 184 liters greywater reused for watering about 22 sq.m area of vegetable seed plants daily. That means about 10 litre of greywater is required for one sq.m area of irrigation.
Assuming 4 personââ‚¬â„¢s average residence in a quarter of NEERI Colony, the greywater generation is estimated to the 316 liters/day (79 Lpcd).
Total population in NEERI East and West Colony, Research Scholar Home and Guest House is considered to be = 1,000 persons.
Total greywater generated in NEERI Colony = 79 x 1,000 = 79,000 lit/day (79.00 cum/day) can be used for gardening/irrigation purposes.
About 7900 sq.m area can be irrigated by reusing of greywater of 79.00 cum. in NEERI Colony daily.
Total amount can be saved by reusing of greywater (79.00 cum.daily) = 79.00 x 20 = Rs.1580.00 lit/day = Rs.5,76,700/year (water charges Rs. 20 / cum of water).
If all the greywater reused in NEERI Colony for gardening/irrigation etc (Outdoor use), then about Rs. 5.77 lakhs / year can be saved.
18.104.22.168 Operation and Maintenance of GTP in Quarter No.D-6 of D-Block, NEERI Colony
A weekly cleaning is maintained to remove the choked large particles, materials from foams and initial coarse filter chamber which is installed before the treatment plant.
About two to three tea spoons full of bleaching powder is mixed in storage tank (sump) for about 320 litres daily to maintain about 0.1-0.2 mg/L residual chlorine in treated greywater to kill the pathogenic bacteria which spread diseases.
Treated greywater is used daily for watering the gardens, irrigation and toilet flushing as it begins to run septic and gives bad smell.
Treated greywater is pumped to overhead roof tank and used daily. It is observed that, treated and infected greywater can be stored up to two days without any bad smell.
Dry leafs of surrounding big trees are fallen down in the treatment plant, which is removed in weekly or 15 days to avoid pollution.
During heavy rains greywater is diverted to sewer line to avoid over flows and failure in treatment plant system. In such situation rain water collected in storage