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.