Sewage and sludgeSewage and sludgeSewage and sludgeSewage and sludge

Concentrated organic manures

Class: 6

and

Concentrated organic manures

Oil cake, Bone meal, blood meal, fish manure, meat meal etc.

Oilcakes: is the residue left after the oil is extracted from oil bearing seeds

Edible oil Cakes : feed to the cattle

Coconut cake : 3.0% N

Mustard Cake : 5.2% N

Ground nut cake : 7.2% N

Safflower cake : 7.9% N

Sesame cake : 6.2% N

OC should be well powdered before application for quick decomposition nutrients are liberated after decomposition of oil cakes,

C:N=3-15, low, nitrifies quickly, nearly 50-80% N is available within 2-3 months, Used as top dressing

Concentrated organic manures has no residual effect

Except Mahua Cake Oil Cake may apply as top dressing

Non-edible Oilcakes

Castor Cake : 4.3% N

Neem cake : 5.2% N

Mahua Cake : 2.6% N

Toxic substances: (Saponin) Muhua cake- poorest N available after 2 months of appln.

Suitable for orcahrd , Long Day Crop like Sugarcane, Tapioca

Neem cake: used for controlling nematodes @ 1 t /ha

Use as a fertilizer: Neem cake organic manure protects plant roots from  Nematodes, soil grubs and  White ants probably due to its residual limonoid content.

It also acts as a natural fertilizer with pesticidal properties. Neem cake is widely used in India to fertilize  paddy , cotton and sugarcane.

Neem seed cake also reduce alkalinity in soil, as it produces organic acids on decomposition.

Being totally natural, it is compatible with soil microbes, improves rhizosphere microflora  and hence ensures fertility of the soil.

The cake contains salannin, nimbin, azadirachtin and azadiradione as the major components.

Hoof and Horn Meal organic fertilizer is a great source of N (12%) for  organic garden plants, especially high feeders like corn, tomato and lettuce.  It also has  a small amount of P (2%) for healthy roots and stems.

It  is made from cooked ground dehydrated cattle hooves and horns obtained from slaughterhouses.

H&H Meal is equivalent to  Blood Meal  in N content, but the nutrient availability is slower, which is better for organic crops and with less "leaf burn" damage and it contains P.  It nutrient availability starts at around 4-6 weeks and can

lasts 12 months.

Bone mealEssentially P fertilizer, slow acting manure, apply at the time of planting or sowing, suitable for acid soil, rich in sesquioxides

Bones consisits of Ca3 (PO4)2 together with some organic substances like fats and protiens.

So, good source of Lime, phosphoric acid and N

The presence of fat hinders the process of decomposition. Therefore, bones are sometimes treated with steam to remove fat before they crushed. Steamed bone meals are more brittle, and easy to crush and decomposes quickly.

Bone meal Steamed bone mealTotal P 20.2 22.0Avail P

(citrate soluble)8.0 16.0

200 major cities in India generate 2600 million m3 of raw sewage per year

Production of sludge is estimated to be around 1200 tonnes per day, potentiality is 4000 tonnes per day

Delhi city produces 600 Mm3 of waster water per day, 175 Mm3 untreated

Five major sewage treatment plants in Delhi produce 1200 M lit treated effluents per day-used to irrigated crops

Sewage sludge –a potential threat to heavy metal pollution in Indian soils

Disposal of sewage effluents for irrigation

Sewage has two components,

Solid portion technically known as sludge

Liquid portion, commonly known as sewage water or effluent . The raw or crude sewage consists mainly of water carrying various solids partly in soln and partly in suspension

Both the components of sewage are used in increasing Both the components of sewage are used in increasing crop production but due to crop production but due to bacterial contaminationbacterial contamination untreated sewage is not advocated for growing untreated sewage is not advocated for growing vegetablesvegetables

Bacterial contamination is reduced by fermentation and Oxidation treatment

Settled sludge :- Produced by plain sedimentation

Digested activated sludge :-

Digested sludge:- Digested sludge is obtained from raw sewage through settling by gravity and sedimentation. The solid parts subsequently digested anaerobically for a period of 10-15 days. This digested material is then pumped in suitable beds for drying out. This sludge’s usually gave an offensive odour but they are free from pathogenic organisms present in unprocessed sludges

Activated sludge: produced by a special rapid aerobic treatment of sewage that results in coagulation and settling of suspended materials. This pdt is superior to digested sludge and has no offensive adour.

Chemically precipitated sludge:- Produced by treatment of certain chemicals to remove certain poisonous

compounds and heavy metals as also to precipitate the dispersed material.

Activated sludge contains :

3-6% N, ~ 2% P2O5 and 1% K2O in form a that can become readily available when applied to soil. (ISSS,2009)

On an average, the sewage sludge has the following composition on oven dry basis

Composition Amount on oven dry weight basis (%)

Organics 40-50

Inert materials 30-40

Bio-resistant organics 10-15

Miscellaneous substances 5-8

Basic flow of sewage sludge composting process

Composition of Sludge

N (1.5 – 3.5% ) P (0.75- 4.0%) K (0.3- 0.6%)

Sewage: Effluent waters which should be removed from settlements and industrial enterprises are known as Sewage

food wastes, various washings and laundry wastes, waters from lavatories, baths etc.

waste waters are unstable polydispersed system

Inorganic impurities are sand, clay, particles of ore, slag, chalk, mineral salts, mineral oils

Municipal sewage

Sewage water : can be used as an irrigation source. However, it should be treated before application to fields.

Soil sickness: results from excessive organic and N loading, which causes anaerobiosis and imbalance in C:N and C:P.

Excessive N-loading: also induces production of more foliage, resulting in less fruiting, particularly in the case of vegetables like brinjal, okra, chillies.

The yield decline: due to continuous application of untreated sewage water is primarily due to blocking of soil pore spaces by colloidal matter. The soil quickly becomes sewage-sick.

Industrial sewage

special methods of the treatment are reqd.

(i) NaCN+ H2SO4→ (Na)2SO4 + HCN (260C)

(ii) NaCN + HOCl = CNCl + NaOH

CNCl + H2O → HCNO + HCl

HCNO + Cl2 + H2O → CO2 + N2 + 2HCl

(at pH 10.0)

Cyanogen chloride

Cyanic acid

Crops suitable for sewage irrigation

Fodder crops like Oats, Jowar, Maize, berseem and lucerne

Sugarcane

Vegetable crops, like Cabbage, cauliflower, turnip, potato, brinjal, lady’s finger, beans etc.

Crops unsuitable for sewage irrigation

• Tomato

• Radish

• Onion

• Ggarlic

• Carrot and leafy vegetables

Heavy metal composition of sewage sludge from different cities in India

City Cu Zn Cd Cr Ni Pb

  mg/kg

Ahmeda

bad

535 2147 3.5 60.4 32.3 76.8

Delhi 440 1610 5.5 53.5 81.5 34.5

Nagpur 272 832 1.5 49.2 14.8 24.3

Chennai 210 935 8.3 38.5 60.5 16.6

Jaipur 265 1720 7.3 17.6 37.5 66.9

Source : Maity et al (1992).

DTPA-extractable heavy metals in soils under different crops irrigated with sewage and underground water

Crop Source of Zn Fe Cu Mn Cd irrigation water mg/kg

Berseem Sewage 13.4 75.3 24.4 33.2 0.119 Underground 4.20 38.0 7.80 28.4 0.074

Spinach Sewage 41.2 65.6 32.2 28.8 0.253 Underground 4.20 59.4 7.00 24.4 0.079

Coriander Sewage 21.1 69.0 49.4 23.0 0.208 Underground 6.60 32.4 9.50 18.4 0.054

Source: Sharma and Kansal(1986)

DTPA-extractable heavy metal status in Peri-Urban Soils (treated with sewage) during Summer of 2001Soil sample DTPA-extractable heavy metal content/mg.kg-1

Pb Cd Cr

Kalyani 0.35 1.70 0.63 Mahishtala-2, Dhapa 0.70 1.00 7.207.20Mathpukur 1.08 1.21 4.18

Tangra, Dhapa 1.52 12.6 4.96

Bantala 1.68 17.0 18.9South Mahishtala, Tiljala 1.70 0.58 8.30

Barasat 2.88 1.04 3.54Titagarh 1.96 1.01 2.30

Kolaghat 0.51 1.82 5.62

Source: Sanyal (2002)

Distillery Effluents (Spent wash)Distillery is one of the most important agri based industries in India for manufacturing of ethyl alcohol from molasses. A large volume of foul smelling effluent which is commonly known as distillery effluent or spent wash is generated.

Usually with 1 L of alcohol production 12-15L spent wash effluent is generated. Approximately 40 billion Litres of spent wash is generated/ annum from 285 distilleries in the country, which is generally discharged in to the water courses under untreated or partially treated conditions, causing environmental pollution owing to its very high organic load.

In order to reduce its high biological oxygen demand (BOD) and Chemical Oxygen Demand (COD), many distilleries recycle these effluents to produce methane by passing them through biomethanation digesters and the effluent thus obtained is known as Post methanation effluent (PME)

Let the Hundred flowers bloom pabitramani@gmail.com

http://www.bckv.edu.in

Feedstuffs Toxic factors

Groundnut and its meal

Trypsin inhibitor, goiterogen, tannins,

Mustard or rape seed and its meal

Goiterogens (thioglucosides or glucosinolates), tannic acid, erucic acid, sinapine (cholinester), pectins

Safflower seed and its meal

Estrogenic factor, Two phenolic glucosides (Bitter flavour)

Sunflower seed and its meal

Chlorogenic, quinic-acid

Sesame seed and its cake

Phytate and Oxalates

Linseed and its cake

Linamarin (cyanogenic glucoside), antipyridoxine (Linatin)

Feedstuffs Toxic factors

Neem seed

and its meal 

Bitterness → Limonoids → Triterpenoids

Nonisoprenoid polypenolics- Flavanoids,

Tannins and coumarin viz.  Nimbin, Salannin and Azadirachtin

Mahua cake Mowrin (Saponin) and Tannins

Fish meal and meat meal

Gizzerosine and histamine

Heavy metals

Sewage-sludge

Sewage-sludge

Drying Bed

Irradiation vessel

28

Treated water

Excess Sludge

ClarifierFeed

Mixed Liquoror“Sludge”

Returned Activated Sludge (RAS)

Settled Sludge

The Activated Sludge ProcessThe Activated Sludge Process

OXYGEN

OXYGEN

Pure Oxygen

Classical Oxygenation by sidestream oxygen injection

Recirculation Pump Activated Sludge Basin

Water Water IntakeIntake

Secondary EjectorSecondary Ejector

Venturi-typedevice

The OXY-DEP® processTypically fromLiquid Oxygen