FIELD OF THE INVENTION:
This invention relates to a system and process for recycling and treatment of parboiling waste water from parboiling plants.
This invention further relates to a system and process for conservation by recirculation of water in paddy parboiling plants.
BACKGROUND OF THE INVENTION:
Water quality and human health have been closely linked throughout history. However, it was not until the last quarter of the 19th century that pioneering work by Robert Koch and Louis Pasteur established the germ theory of infectious disease. With the understanding that fecal-borne bacteria, viruses, and protozoans responsible for most water-borne diseases, it was possible to develop sanitation and water treatment practices which provided people with a safe water supply. In industrial countries safe water is now taken for granted.
Contrary to what many people believe, it is not necessary to boil water to make it safe to drink. Also contrary to what many people believe, it is usually not necessary to distill water to make it safe. Heating water to 50°C (122°F) will kill all germs, virus, and parasites. This process is called pasteurization and it use for milk is well known though milk requires slightly different time temperature combinations. One obvious problem that arises with pasteurization is the question of how to tell when and if the water has reached the right temperature. Pasteurization will not help if water is brackish or chemically contaminated.
The physical factors which influence pasteurization process are the following:
• temperature and time;
• acidity of the products;
• residual air in product.

Pasteurization processes. In pasteurizing certain acid juices for example, there are two categories of processes:
a) Low pasteurization where pasteurization time is in the order of minutes and
related to the temperature used; two typical temperature/time combinations
are as following:
45°C to 50°C over 100 minutes 75%: over 8 to 10 minutes.
Pasteurization temperature and time will vary according to:
•Nature of product; initial degree of contamination;
•Pasteurized products to rage conditions and shelf life required.
In this first category of pasteurization processes it is possible to define three phases:
• heating to a fixed temperature:
• maintaining this temperature over the established time period (=pasteurization time):
• cooling the pasteurized products: natural (slow) or forced cooling.
b) Rapid, high or flash pasteurization is characterized by a pasteurization time
in the order of seconds and temperatures of about 85° to 90°C or more,
depending on holding time. Typical temperature/time combinations are as
follows:
88°C (190°F) for 1 minute;
100°C for 12 seconds; 121°C for 2 seconds.

While bacterial destruction is very nearly equivalent in low and in high pasteurization processes, the 121°C/2 seconds treatment give the best quality
products in respect of flavour and vitamin retention.
Such short holding times, however, require special equipment which is more difficult to design and generally is more expensive than the 50-65°C/120 minutes type of processing equipment.
The thermo-penetration is extremely important, especially in the case of the pasteurization of products because it is the determining factor for the success of the whole operation. During pasteurization it is necessary that a sufficient heat quantity is transferred to product; this is in order that the product temperature rises sufficiently to be lethal to micro-organisms throughout the product mass.
There is a severe problem of water pollution caused by parboiling waste water: Disposal of waste water from parboiling plants in the rice mills adversely affects the surrounding atmosphere; The waste water is unsuitable for drinking, agriculture and industry; destroys aquatic life. Further disposal of this water causes offensive flavor due to release of methane and hydrogen sulphide. The crops in surrounding areas are destroyed and soil productivity is reduced to a great extent.
OBJECTS OF THE INVENTION:
It is therefore an object of this invention to propose a system and process for recycling and treatment of parboiling waste water from parboiling plants. It is a further object of this invention to propose a system and process for recycling and treatment of parboiling waste water by pasteurization and thereby reduce the fresh water requirement for parboiling process.

It is a still further object of this invention to propose a system and process for recycling and treatment of parboiling waste water from parboiling plants by the recirculation of water in paddy parboiling plants, to reduce the process water demand.
Another object of this invention is to propose a system and process for recycling and treatment of parboiling waste water from parboiling plants by recirculation of water in paddy parboiling plants, which destroys or inactivates micro organisms from water and thus eliminates smell and other putrid products in rice.
Yet another object of this invention is to propose a system and process for recycling and treatment of parboiling waste water from parboiling plants by using high temperature discharge water in recycling, reducing the requirement of thermal energy for heating the water to soaking temperature.
Yet another object of this invention is to propose a system and process for recycling and treatment of parboiling waste water from parboiling plants by the recirculation of water in paddy parboiling plants, which improves the quality of resultant rice.
Another object of this invention is to propose a system and process for
recycling and treatment of parboiling waste water from parboiling plants to
reduce the need for water treatment plant making the parboiling more
economical.
These and other objects and advantages of the invention will be apparent from
the ensuing description, when read in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING;
Fig. 1: Flow diagram of the process technology according to the invention.

DETAILED DESCRIPTION OF THE INVENTION;
Thus according to this invention is provided a system and process for recycling and treatment of parboiling waste water from parboiling plants. In accordance with the invention, is provided a system for recycling and treatment of parboiling waste water from parboiling plants, said system comprising a water storage tank (1), a control system (5) operatively connected to the water storage tank (1) via (i) a steam injector (ii) a temperature probe and (iii) a plurality of water level probes. The water storage tank (1) is configured to receive fresh water via a pump (2), pump water at a pre-determined temperature to a soaking tank (4 ) via a pump (1) and receive waste water via a pump (3) from a soaking tank (4) .
The control system (5) is coupled to the PLC and said PLC is configured to control level of water in the storage tank.
The PLC is also configured to control temperature between 50-55° C in the storage tank and is further configured to control the volume of steam from the steam injector.
In accordance with this invention is further provided a process for the recirculation of water in paddy parboiling plants, where the technology is based upon low-temperature-long-time (LTLT) pasteurization of water. The flow diagram of the process technology is shown in figure 1 of the accompanying drawings..
The process for the recirculation of water in paddy parboiling plants comprises filling a water storage tank (1) with water at 1.25 kl water per ton of paddy, heating said water in the tank to a predetermined temperature by steam injection, providing the heated water to soaking tanks provided with paddy and soaking the paddy, discharging the soak water, pumping said discharged soak water into water storage tank, and making up the volume by adding balance cold water at 0.35 kl per ton of paddy, heating the water in the water

storage tank, maintaining the water at a predetermined temperature to pasteurize the water, recycling the pasteurized water to the soaking tank for soaking the next batch of paddy.
In each cycle about 2-5% water is automatically discharged from the water storage tank to remove sediments from the bottom of the tank. The water in the water storage tank is maintained at a temperature of 50-55° C and, the water in the water storage tank is heated by steam injection. The pasteurization of the water in the hot water tank is effected by holding the water at 50 - 55° C at least for 3 - 5 hours.
The level of water in the water storage tank, the temperature in the water storage tank, addition of cold water to the water storage tank and discharging sediment - containing water from the water storage tank are automatically controlled by the PLC.
In accordance with an exemplary embodiment, the process consists of the following steps:
1. Water tanks are filled with fresh water at the rate of about 1.25kl/ton of paddy. Water tanks are equipped with high and low level sensors both at the top and bottom ends of the water tanks. Levels in the tanks are controlled automatically by the PLC.
2. The soaking water in the tanks is heated to a temperature to get to desired soaking temperature, by steam injection. Hot water temperature is controlled by PLC.
3. After soaking, waste water is discharged at the rate of about 0.9 kl/ton of paddy. This discharge is pumped to the hot water tank and balance coldwater at the 0.35 kl per ton of paddy is added to the discharge water. This operation is automatically accomplished by the PLC.
4. There cycled water is heated to 50-55°C by steam injection. For
pasteurization the water mass is required to be maintained within these

limits for a minimum 3 hours in order to kill deteriorative microrganisms in the water. There cycled water may be stored for several days if water temperature is maintained within 50-55°C as higher temperature will not
allow microbial growth in water. Again the temperature of recycled water is maintained by steam injection automatically.
5. The pasteurized recycled hot water from step 4, is used for soaking of next batch of paddy.
6. Steps from 3 to 5 are repeated for all subsequent batches.
7. In each cycle about 2-5% water is automatically discharged from the hot water tank to remove the sediments from the bottom, after filling the soaking tanks.
8. If for some reason the water temperature in the soaking tank falls below
45°C entire contents of the hot water tank are automatically discharged.
The entire process of soaking using recycled water is fully automatic. Recycling of water increases TDS to 115mg/d land reduces the pH of soaking water to about 3 at equilibrium. This makes the soaking pH acidic which helps in making the resultant rice light in color and of better shine.
This process achieves conservation of water. Water requirement is reduced from 1.25kl to 0.35kl per ton of paddy processed. Water demand for the parboiling process is reduced by 3.5 Times. There is a low steam requirement in heating of water. Only 0.31kg steam at 2bar pressure is required per ton of paddy. The process also eliminates need for expensive water treatment plant. High temperature destroys or inactivates micro organisms from water and thus eliminates smell and other putrid products in rice and improves the quality of the resultant rice.

We Claim:

1. A system for recycling and treatment of parboiling waste water from
parboiling plants, said system comprising:
a water storage tank (1) configured to:
receive fresh water via a pump (2)
pump water at a pre-determined temperature to a soaking tank (4 )
via a pump (1)
receive waste water via a pump (3) from a soaking tank (4) a control system (5)
operatively connected to the water storage tank (1) via (i) a steam injector (ii) a temperature probe and (iii) a plurality of water level probes.
2. The system as claimed in claim 1, wherein the control system (5) is coupled to the PLC.
3. The system as claimed in claim 1 and 2, wherein said PLC is configured to control level of water in the storage tank.
4. The system as claimed in claim 1 and 2, wherein said PLC is configured to control temperature between 50-55° C in the storage tank.
5. The system as claimed in claim 1 and 2, wherein the PLC is configured to control the volume of steam from the steam injector.
6. A process for the recirculation of water in paddy parboiling plants
comprising filling a water storage tank (1) with water at 1.25 kl water per ton of
paddy, heating said water in the tank to a predetermined temperature by steam
injection, providing the heated water to soaking tanks provided with paddy and

soaking the paddy, discharging the soak water, pumping said discharged soak water into water storage tank, and making up the volume by adding balance cold water at 0.35 kl per ton of paddy, heating the water in the water storage tank, maintaining the water at a predetermined temperature to pasteurize the water, recycling the pasteurized water to the soaking tank for soaking the next batch of paddy.
7. The process as claimed in claim 6, wherein in each cycle about 2-5% water is automatically discharged from the water storage tank to remove sediments from the bottom of the tank.
8. The process as claimed in claim 6, wherein the water in the water storage tank is maintained at a temperature of 50-55° C.
9. The process as claimed in claim 6, wherein the water in the water storage tank is heated by steam injection.

10. The process as claimed in claim 6, wherein pasteurization of the water in the hot water tank is effected by holding the water at 50 - 55° C atleast for 3 -5 hours.
11. The process as claimed in claims 6 and 7, wherein the level of water in the water storage tank, the temperature in the water storage tank, addition of cold water to the water storage tank and discharging sediment - containing water from the water storage tank are automatically controlled by the PLC.