The pre-requisite for the concept of common treatment is the treatment at low cost . With more and more improvisation and stress  on  in-house  measures,  it  is  now  established  that the nature of job in small scale industries has immense potential of not only adopting certain measure to control pollutants at source thereby reducing pollution load and cost of treatment but also to reap rich benefits. Some examples are summarised below :

Industry	Measures	Benefits
Hosiery	Manufacturing liquid detergent from spent kier liquor	l Reduction in pollution load
Electroplating	Reactive rinsing by use of rinsewater after alkaline cleaning for rinsing components after pickling	l Reduced water consumption and wastewater generation l Effective cleaning of components
	Modification in dragout tray arrangements (hang the workpiece vertically instead of dragging out horizontally)	l Better rinsing l Reduced chemical consumption
	Installation of double plating line instead of single line inn plating bath	l Enhanced production capacity
Cotton dyeing	Substituting soda ash by caustic soda in dyeing process	l Reduced chemical consumption
Tannery	Installation of flow meter	l Exact measurement of water / chemical
	Scrapping salt from hides before rinsing	l Salt recovery, low TDS in effluent
	Measurement of chemicals by weight and not by volume	l Reduced wastage of chemicals
	Substitution of Benzidine based dye with non- Benzidine based dye stuff	l Elimination of toxicity due to dye stuff
	Recycling of spent alkaline bath after screening for next batch	l Reduction in chemical consumption and pollution load
Small pulp & paper	Increase in wire mesh size in de-pither	l Increased pith recovery l Decrease in chemical consumption

Courtesy : NPC

Various systems for cost sharing as exercised by Common Treatment provisions operating in India as well as in other countries are discussed below. The concerned management body can opt the most suited and viable system based on the local situation and feasibility to implement. The system exercised in most of CETPs operational in India is partly based on Quality-Quantity method with case specific modifications.

1. Quantity Method

• Simplest Method and applicable for joint treatment of sewage and low strength industrial waste
• Operation cost and the cost for debt service are divided by total volume(quantity) of waste in a given time
• Advantageous where nature of waste from industries are generally uniform.

1. Quantity – Quality method

• Charges are proportional to the benefits from the treatment plant. The computation of treatment cost can be summarised in following steps:

Step-2
Work-out fixed cost (depreciation, loan repayment etc.) and operational cost on annual basis, for all major components like conveyance system, pumps, clarifiers, digesters etc.

Step-3
Identify the variables (BOD, SS , volume) and extent of dependence the variable is considered for design specification for the given component. eg. Conveyance system and digesters are designed based primarily on volume and SS respectively, whereas for clarifier , volume and SS are equally considered.

Step-4
Work-out apportionment of the total treatment cost (fixed and operational), based on the function of the variables.

Step-5
Depending upon design specification of the plant, against critical parameters, work out the cost component for unit volume treated, kg BOD removed and kg SS removed .

Step-6
Calculate the cost of treatment for effluent from any industry based on unit cost component as in Step-4 and effluent characteristics in terms of quantity (volume) and quality (BOD, SS etc.) for the given industry.

• Based on " Polluter Pays" principle
• The factors considered in cost computation are volume, degree of noxiousness ‘S’ of wastewater and dilution factor ‘V’ to ensure survival of fish (48 hr. exposure)

V = A/A_o + B/B_o + TDS/ TDS_o + F – 1

Where A = Settleable matter , mg/L

B = COD of settled sample, mg/L

TDS = Total dissolved solids mg/l

F = Fish Toxicity

A _o , B_o , TDS_o = Standards

• Noxiousness degree ‘S’ is estimated from dilution factor expressed in appropriate slabs
• Annual treatment cost apportioned to each polluter is calculated as follows:

Cost Share = S. Q . Z. / S (S. Q.)

1. Fukashiba formulation

• Japanese system adopted for CETP catering to petrochemical industries
• Charges levied are calculated differently on the basis of quantity and differently for quality
• While quantity rate is mutually decided and is binding to all member industries, the quality rate is determined based on B. O. D. , C.O.D., Suspended solids and concentration of N-hexane extract in effluent from individual industry

1. Roman Formulation

• Based on the idea that :

1. Construction cost of CETP should correspond to the volume and strength of effluent from individual industry
2. Conveyance cost should be proportional to the volume by each industry irrespective of its distance from CETP

• Provision of penalties in terms of transgression of ‘discharge volume’ regulated for each industry
• Incorporates Roman concept that economic aspect of pollution control should never be considered as the main factor influencing economic decision.
• Different factors considered in cost computation are:

1. Avg. flow of effluent from industry to CETP
2. Total flow of effluent reaching CETP
3. Construction cost of CETP
4. Construction cost of all additional facilities used for conveyance of effluent
5. Avg. strength of effluent of the given industry expressed as BOD₅ in kg O₂ / m³
6. Avg. strength of total effluent expressed as BOD₅ in kg O₂ / m³
7. Cost of treatment plant units depending on the pollution load to construction cost of the whole treatment plant.

1. Chemtech Formulation

• This formulation is based on the proportion of the CETP usage
• Industries pay according to their volume of effluent and the influence of chemical, physical and biological conditions of the waste on capital and operational cost of CETP.
• Cost of neutralisation at CETP is not considered as this is considered to be a part of pre-treatment by the industry.

1. Graduated Payment Formulation

• Based on concept of graduated payment, whereby:

1. Large industries pay marginally higher cost
2. Cost paid by smaller industries is fixed as minimal amount thus eliminating intricate accounting procedures
3. The cost for large or medium industries can be calculated based on factors which include effluent generation of individual industry, total quantum of effluent reaching CETP and pollution factor ‘P’ as follows:

1. Flecksedar Methodology

• Cost apportioning can be attempted based on following system:

1. Cost be adjudged separately for designed and actual treatment capacity of CETP
2. The type of treatment and the cost incurred on it , be levied from the industry(s) responsible for particular pollutant

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