Implementation of Wastewater Treatment Plant at Fully Automated Beet Sugar Mill

IndustrySouth-East European INDUSTRIAL Мarket - issue 6/2009

Kayseri Sugar Factory is one of the biggest producers of beet sugar in Turkey. Before the wastewater treatment plant (WWTP) establishment its all excess water was collected in primitive lagoons, without water-retaining systems.
The main contractor of the WWTP project was engineering company ARTAS A.S. The technology partner designed and commissioned Anaerobic Wastewater Treatment System was Lars Enviro Pvt. Ltd., India.

About the project
Wastewater from sugar manufacturing facilities has a high organic load and should be treated on site.
Typical levels of COD:
• 2,300-8,000 mg/L from cane processing
• up to 10,000 mg/L in beet processing.
Sugar Beet Processing- Kayseri
Sugar WWTP Design Basis:
COD (mg/L): 7600
TSS (mg/L) : <500
TKN (mg/L) : 100
Flow:
6000 m 3/d wastewater (Bruckner’s water & process water)
2400 m 3 /d condensate overflow
Total capacity of WWTP: 8400m3 /d.
The process objective was To reach effluent standards   of  Turkish Legislation for Sugar Industry:
COD : 450 mg/L
TSS : 100 mg/L
pH : 6 - 9

The treatment basis included anaerobic treatment (6000 m3 /d wastewater) followed by aerobic treatment (6000 m3 /d anaerobically treated wastewater + 2400 m3 /d condensate overflow).
In the campaign period after the project completement Kayseri Sugar Factory production amounted 960 000 ton of beet (2007-08 campaign). In the production process the factory utilized 5m3 water for ton of beet. The wastewater (after internal recycling) was 1m3 wastewater/ton of beet. Total amount of wastewater collected (to be treated) was 1 000 000 m3.

Construction of the plant
Due to shallow ground water table and weak & highly compressible soil, Artas have used thick RCC slabs & geo-synthetic material to counter uplift pressure on the foundation.
Steel Tanks Fabrication - all the plates and structural members were shop-fabricated, sand-blasted and primer-painted at workshop. The entire erection work was done using cranes.
To prevent freezing of the equipment and water in pipes the hot water pipes are insulated also the equipment and instruments caged.
The Plant Operation
The operations in waste water treatment plant are controlled via SCADA (supervisory control and data acquisition) system. Live data is shown as graphical shapes over a static background. As the data changes in the field, the foreground is updated.
This on-line process control system displays the parameters of all main instruments: Flowmeters; pH meters; Pressure Transmitters; Temperature Transmitters; Level Transmitters, etc. Also the valve and motor positions (as on/off); Start/stop the pumps (time referance if desired); Open/close the valves (time referance if desired) and Frequency adjustment of the motors. The values are displayed on the screen.
The past data is stored. Trends (graphs) of analogue values are stored too.
Monitoring & Analysis
Monitoring of the WWTP is realized by SCADA monitoring and recording. Also operators are taking hourly pH and temperature data from the critical points (using electronic hand -instruments) and samples for laboratory analysis.
Seeding and Commissioning
• Highly active seed from an operating Sewage Treatment Plant was used for seeding the reactor. TSS concentration was around 45000 mg/L.
• Liquid content from the existing lagoon was also used as seed supplement.
• Seed Transfer along with raw wastewater continued for about 10 days to make up top liquid level of HYT and LESAR reactor.
• It took about 30 days since then to reach ’full feed’ condition with all parameters under control.
• This being first campaign, Kayseri decided to route the raw wastewater through existing lagoons before feeding it into WWTP.
• For next season, the wastewater would be taken directly into WWTP.

WWTP Performance
Steady State Anaerobic Process Performance
• Average flow : 6037 m3/day
• Inlet COD : 1716 mg/L
• Inlet pH : 6.6 - 6.8
• Reactor temp. : 36 - 37 deg C
• Outlet COD : 125 mg/L
• COD removal : 92 %
• Vol. acids/ alkalinity ratio : 0.14 - 0.25
• Biogas generation : Flared
Steady State Aerobic Process Performance
• Condensate water flow : 2110 m3/day
• Average inlet COD : 460 mg/L
• Average Combined flow : 8135 m3/day
• Combined Inlet COD : 193 mg/L
• Outlet COD : 25 mg/L
• Outlet TSS : 14 mg/L
• MLSS : 4353 mg/L

Biogas Burning
As part of its environmental strategy Kayseri Sugar is planning an investment for energy generation from biogas. Anaerobic bacteria break down organic material in the absence of oxygen and produce "biogas" as a waste product.
Biogas Produced:
Methane (50-80%), carbon dioxide (20-50%), and trace levels of other gases (H2 ,CO, N, H2S). Methane is highly flammable, explosive and difficult to detect. All biogas is burned via automatic flare. Kayseri Sugar is planning an investment for energy generation from biogas (electrical generation by burning it as a fuel in a gas turbine or steam boiler).
Fully automatic flare for the incineration of biogas:
1. Electric ignition (ignition transformers and ignition electrodes)
2. Automatic valve with electric motor drive (for automatic closing and opening of the gas pipe.)
3. Flame- arrestor (near the gas torch)
1. Electric ignition (ignition transformers & ignition electrodes)
4. Flame control :Automatic firing built in the switchboard; UV flame - sensor
5.Switchboard providing the fully automatic control of the flare.

Source: ARTAS A. S. web presentation




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