Post on 30-Oct-2021
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.