liquid waste management -...
TRANSCRIPT
Liquid Waste management Date: 13 March 2018
Liquid Waste (Any waste that is in liquid form)
Improper disposal of liquid waste leads to
Pollution of water bodies
Pollution of groundwater
Breeding of mosquitoes, bad odour
Spreading of diseases
Deterioration in the aesthetic beauty of places
Liquid waste classification
Liquid waste
Domestic
Sewage Sullage
Industrial
Effluent from industrial process
Eg: effluent from municipal markets, slaughter houses and industrial
process
Sewage
• Black water - Mixture of Urine, Faeces and flush water (35% of total wastewater
• Grey water - Water generated from Kitchen, washing of clothes, bathing water and floor cleaning water (65% of total wastewater
• Sewerage - Pipe network carrying sewage
Wastewater Characteristics
• BOD – measure of biodegradable organics, approximate quantity
of oxygen required for biological stabilisation of the organic matter
• COD – measure of quantity of oxygen required for stabilizing biological as well as chemical pollutants
• TSS – Total suspended solids
• Faecal Coliform – Indicator bacteria for pathogens
Before and after Wastewater treatment (taken sewage as the wastewater)
Characteristics Before treatment After treatment
pH 5.5 - 9 6.5-9
BOD 250-300 mg/l <30 mg/l
COD 600 mg/l <250 mg/l
TSS 200 mg/l <100 mg/l
Faecal coliforms
106 MPN/100 ml <1000 MPN/100ml
* The concentration of contaminants in industrial wastewater could be higher than that of
Sewage. The characteristics of treated effluent should conform to the regulatory authority
Wastewater treatment Chain
Primary treatment
(Physical Process)
• Removal of solids
• Screen
• Grit chamber
• Primary settlers
Secondary treatment
(Biological Process)
• Removal of organic content
• Anarobic process
• Aerobic process
Tertiary Treatment
(Chemical/Pholtolytic process)
• Disinfection – pathogen removal
• Chlorination
• Ultra violet
Screens Grit removal Primary settler
Biological process
Secondary settler Filtration Disinfection Treated water
Sludge drying bed
Typical Sewage treatment flow chart
Wastewater
Sewage management systems
Sewage management
models
Centralised treatment
(eg: Muttathara sewage treatment plant in TVM)
Decentralised treatment
(Institutional level)
Sewage Treatment Systems
Centralised treatment
High capital cost
Not suitable for high water table area
Practical difficulty in sewerage laying
Project implementation time longer (3-5 years)
Reduces reuse of treated resources
Decentralised treatment
Treatment systems at institutional level or treatment systems for small population
Less capital cost
Project implementation time short (6 months-1 year)
Allows segregation wastewater streams and encourage reuse options
Decentralised treatment (Institutional level)
• Hospitals
• Educational institutions
• Municipal markets
• Slaughter houses
• Residential Apartments (Having more than 300 residents)
• Large office complexes
• Recreational water theme parks
• Industries
Wastewater management in Institutions
Selection of wastewater treatment systems
Quantify the amount of wastewater to be treated (usually 80% of the water demand)
Assess the characteristics of wastewater in accredited laboratories (BOD, COD, pH, TSS, Faecal coliform content)
Assess the nature of soil and groundwater table in the area
Depending on the Wastewater characteristics and site specific conditions treatment process are selected
Land area available and amount of money also affects treatment configuration
Wastewater Quantification guidelines (ref: CPHEEO manual)
No Institutions Water Supply (litres/day)
1 Hospital including laundry and beds exceeding 100 450 per bed
2 Hospital including laundry and beds not exceeding 100 340 per bed
3 Lodging houses/hotels 180 per bed
4 Hostels 135 per person
5 Nurses homes and medical quarters 135 per person
6 Boarding schools/Colleges 135 per person
7 Restaurants 70 per seat
8 Airports and Seaports, duty staff) 70 per person
9 Airports and Seaports, alighting and boarding persons 15 per person
10 Train and Bus Stations, duty staff 70 per person
11 Train and Bus Stations, alighting and boarding persons 15 per person
12 Day Schools/colleges 45 per person
13 Offices 45 per person
14 Factories, duty staff 45 per person
15 Cinema, concert halls and theatres 15 per person
Onsite sanitation systems in public institutions (Educational Institutions, Offices etc)
• Septic tanks – Assessment of existing septic tanks, septic have a soak pit?, Water tight?
• 3 R’s - Reduce (can we reduce the amount of water used?, fixing of leaks in taps, flushes etc
- Recycle (Rain water harvesting
- Reuse (Is there any scope of greywater reuse. If grey water is seperated from black water, greywater can be treated inexpensively and use for agriculture, flushing, floor cleaning and toilet washing.)
Wastewater stagnation
On-site wastewater treatment options
1. Greywater treatment systems (as the BOD and COD is lesser than blackwater these systems may not be expensive)
Septic tanks
Grey water
Planted Gravel filter Disinfection
Treated water
2. Greywater Piped root zone irrigation or Soak pit
Decentralised wastewater treatment plants
Septic tank soak pit system can be used for habitats containing up to 300 users
In hospitals the water demand is more than domestic settings
Proposed wastewater plants in LSGIs (to be constructed)
a) Sewage treatment plant in Taluk hospital Sultanbethery
b) Sewage treatment plant in Govt. Ayurvedic Hospital Porakkattiri
c) Wastewater treatment plant in municipal markets Kottakkal and Kanjangadu municipalities
d) Sewage treatment plant in Vadakara Jilla Hospital
Thalipparambu Municipality (wastewater treatment plant)
Faecal Sludge management for onsite sanitation systems
• Majority of households in Kerala use Septic tanks/pits
• Faecal sludge – Waste collected from Septic tanks/Pits
• Faecal sludge collected by vaccum trucks and dumped into water bodies, barren land and drains causing environmental pollution
• Solution to this problem?
Septage treatment plants serving group of Block Panchayats
Eg: Two Septage Treatment plants in Eranakulam district (Brahmapuram and Wellington Island)
Soil conditioner and clean water for agriculture from Septage treatment
Septage Treatment plant in Brahmapuram
Use/Disposal of treated water and sludge
Useful Products from sewage treatment
Organic manure (soil conditioner) from sludge
Treated water for agriculture, construction purposes, toilet flushing, floor and toilet washing etc.
Biogas can be used for cooking or used to make electricity
Disposal of treated water through soak pits, to water bodies or drains
Model for proper wastewater treatment and reuse in non-sewered areas
Faecal Sludge treatment plants
Decentralised treatment plants
Main points
• Systems should be developed for greywater management in institutions where there is an onsite sanitation such as septic tanks
• Liquid waste treatment systems should be implemented in educational Institutions with hostel facilities, hospitals, markets, apartments and slaughter houses
• Treated water reuse for non-potable uses must be encouraged
• Faecal sludge treatment plants for treating septage waste
• Compost production from septage
Thank You