Prevention and Treatment of Industrial Waste Water
Transcript of Prevention and Treatment of Industrial Waste Water
Prevention and Treatment of Industrial Waste Water
Klaas Visscher Yuniko consultancy
Vehbi Duraku Radius consultancy
Introduction
• Industrial wastewater can differ very much from municipal wastewater.
• Approach to deal with industrial w.w. challenge is different and more complex
• Water pollution is a result of raw material/product losses in the production process
• Experiences in The Netherlands learned half of the pollution can be prevented
• More products to sell and less treatment costs• When measuring the pollution degree of the w.w. it is
possible to estimate the product/raw material losses• Focus on food industry especially dairy industry
Steps in waste water pollution control
• Inventory of the sources of pollution– Survey of the water use, volumes and quality
– Setup and control of mass balances for raw materials, water and products
• The triple P-phase: Pollution Prevention Pays– Good housekeeping; prevention of product losses and
leaking of valves
– Reuse and recycling of co- and by-products
• Inventory for needed capacity of end-of-pipe treatment
• Design, selection and construction of a wastewater treatment plant
The effect of milk losses in the factory (1)(calculation example)
- Discharge of 1 litre of milk every day causes a pollution of 1,7 p.e.
- A population equivalent (p.e.) the average pollution load daily discharged by one inhabitant.
- Dairy in the Balkan processes 20 m3 milk per day discharges about 1,500 p.e. (average several dairies Balkan region)
- Product/milk losses discharging 1,500 p.e. is 1,500/ 1.7 = 880 l milk per day.
- 4,4 % (0.880/20) of the milk processed discharged at the sewage.
- Losses of milk in The Netherlands reduced to 0.5 %
The effect of milk losses in the factory (2)(calculation example)
- Yearly costs product/milk losses 880 x 0.30 (price milk) x 300 (production days) = 79,200 euro
- WW Treatment costs Balkan region about 20 euro/p.e
- WW Treatment costs 1500 p.e. is 30.000/year- Total costs product loss and treatment costs
79.200 + 30.000 = 109.200 euro- When product/milk loss reduced to 2 %, savings
of more than yearly 60,000 euro possible. - Pollution Prevention Pays (P.P.P.)
Composition Wastewater
Dairy Whey Municipal
COD mg/l 2000 - 4000 50.000 –
80.000
400 - 600
BOD mg/l 1000 - 2000 30.000 –
40.000
150 - 250
Tot N mg/l 50 - 150 200 - 500 40 - 60
Tot P mg/l 10 - 20 30 - 50 5 - 10
TSS mg/l 300 - 800 100 - 400
Separation of whey
• Whey is a by-product of cheese production and very polluting
• When whey is separated waste water treatment plant can be 2 to 3 times smaller
• Alternative economical feasible options for whey are developed like:
- Production of whey drinks
- Use as cattle feed
- Conversion to biogas
Biogas plant whey KABI
Treatment options
• Biological aerobic treatment
• Biological anaerobic treatment
• Physical chemical treatment
Comparison of wastewater treatment options (1)
Aerobic systems Anaerobic systems Physical-chemical
systemsFeasible for wastewater
with:
Low strength/COD
Low temperature (10-20 °C)
Feasible for wastewater
with:
Medium/High strength/COD
Medium temperature (around
30°C)
Feasible for wastewater
with:
Medium/High strength
Low and medium
temperature
Treatment efficiency:
More than 95 %
Possible to meet standards
for discharge at surface
water
Treatment efficiency:
About 85 %
To meet standards for
discharge at surface water
additional aerobic treatment
is needed
Treatment efficiency:
About 60 %
To meet standards for
discharge at surface water
additional aerobic treatment
is needed
Comparison of wastewater treatment options (2)
Aerobic systems Anaerobic systems Physical-chemical
systems
By-products:
A lot of excess sludge
By-products:
Little excess sludge
Valuable biogas
By-products:
A lot of excess sludge
Operational costs are
high:
Aeration (= energy) costs
Costs of sludge disposal
Operational costs are
low:
Low energy consumption
Energy production
(biogas)
Low costs of sludge
disposal
Operational costs high:
High costs chemicals
High costs of sludge
disposal
Discharge industrial waste water at sewage system
• Waste water treatment plants for the biggest cities like Prizren, Gjakova and Peja.
• Challenges of accepting industrial waste water at the public sewage
• Discharge at a municipal sewage system can be profitable but there are risks
• Technical risks; high contribution to the pollution load and disturbance of the treatment process
• Financial risks; when paying a fair price, industry can implement in-process measures or a pre-treatment, so costs will be much lower
Conclusions (1)
• Waste water pollution in the industry is caused by the losses of raw material and product during the production process
• When analyzing the waste water, these losses can be calculated and estimated
• Reducing losses can save money by selling more products and reduction of waste water treatment costs
• Separating whey at the dairy industry can reduce investments and annual costs waste water treatment significant
Conclusions (2)
• Anaerobic treatment is an economical option for processing of whey and medium and high strengths waste water
• Aerobic treatment is a feasible and sound solution to treat low strength waste water
• Profound investigation of the quantity and quality of the waste water is necessary for a right choice and design of a waste water treatment
• Discharge of industrial waste water at a domestic sewage system has technical and financial risks.