1.Why do we need a Rochem system?

There are many advantages that Rochem has over any other systems available in the market:

• Rochem RO System starts where others End - DT-RO Systems for RO Rejects
• Rochem provides the Lowest Guaranteed Costs: All Inclusive O&M Contract.
• Rochem gives a unique facility which includes all consumables, membranes, etc.
• Rochem also offers a Fixed Price Contract for Periods Desired by the Customer
• Rochem provides its customers with Superior of World Class Technology
• Rochem gives only High Quality Components / Accessories
• Rochem ensures Lower Life Cycle Cost Of System o Rochem has a Strong & Growing Service Network
• Rochem has a Strong Back Up and also full Technical Competency
• Rochem provides Local Service Backup at 12 Locations All over India.

2.What kind of investment is needed for installing Rochem Plants?

The Economic Feasibility of the Rochem DT-RO System for the Application to RO Rejects is as follows:
- 2400 M³/Day System Rs.700 lacs (Approximately - Unpacked Exworks) - Payback for 60% Recovery would be 5 Years without taking into consideration the cost of disposal of rejects and a constant cost of water The Option of Rochem setting up the unit at their cost and charge RCF on the basis of M³ of Permeate Produced with minimum Guarantee Production Quantity and adequate Guarantees towards payments RCF Purchasing the Equipment and Rochem Operating & Maintaining the same at a Guaranteed Fixed Cost

3.Why is the Rochem Disc TubeTM the best in RO?

The patented fluid dynamics and design result in open channel, unrestricted and fully turbulent feed water flow system.
Suspended solids carried in the feed water cannot be trapped or easily settle out inside membrane module.

Infrequent and highly successful maintenance cleaning of the membrane can be achieved using standard in-built cleaning system.

Advantage of the Rochem Module system:

Minimizes membrane fouling and scaling by the unique fluid dynamics of the DT configuration

No/Low Chemical Operating Costs: Unlike other RO systems the Rochem DT Module technology means that no/low permanent feed water pretreatment is required.

Lower Membrane Replacement Costs: In Conventional membrane elements are life-sealed at manufacture. Therefore the complete membrane element must be replaced at HIGH COST.
In Rochem Marine DT Modules it is possible to replace individual sheets at a FRACTION of the COST

Easy Access to all Membranes: Modules can easily be opened up to permit replacement or inspection of each membrane cushion.
This is IMPOSSIBLE on other type of Conventional RO Modules.

High Quality Product Water / Latest Membrane Technology: It is chemically stable. It uses Thin Film Composite (TFC) membrane materials. Using membrane in sheet form means that we can select and accurately control the quality of membrane installation to ensure minimal salt passage to produce high quality permeate

Fail-safe Unattended Operation: the only moving parts are the pumps and it has a fully automatically controlled and failsafe operating functions. Moreover NO Special skills are required to operate the system.

Compact and Flexible Modular Units: The truly modular design and construction of all standard Rochem RO units simplifies transportation and installation and enables flexible use of limited floor space.

Frequently Asked Questions Rochem DT Module™ system used for processing sugarcane molasses based distilleries producing spentwash as the effluent :

1.How does the separation of water from a difficult liquid like spentwash take place?

In this case, the specific configuration of DT Module™ plays the important role of separating the water from spentwash. Had it not been for this configuration, it would have been impossible to separate water. Ordinary configurations (like spiral wound) do not give such separation of water & especially over a long period of time. Once the DT Module takes care of the problems of fouling & choking, the water separation is done by applying pressure against the osmotic pressure generated by the contents of spentwash. The higher the amount of inorganic contents of spentwash, the higher is osmotic pressure created by them & higher is the pressure to be applied to separate the water. The characteristics of the membrane decide the cut off limits of the contents. The separation of water does not entirely depend on the difficult nature of the liquid being processed.

2. What are the characteristics & proportion of water separated from spentwash?

The characteristics & proportion of water to be separated from spentwash depend on the type of membrane used, as well as the starting characteristics of the spentwash. About 98 to 99% of COD, BOD & TDS in the original spentwash can be cut off & the colourless water separated will thus have the balance 1 or 2% COD, BOD & TDS. For normally occurring spentwash (generated @12 to 15 liters per liter of alcohol), Rochem is offering such reverse osmosis membranes, whereby one gets average 50% water recovery. The real limiting factor for the water recovery is the inorganic contents of the spentwash. Depending on the inorganic contents, even from the spentwash generated @ up to 9liters per liter of alcohol, same proportion of water can be recovered.
Can the Rochem system be applied to raw spentwash also?
The application of Rochem system for spentwash does not depend on whether the same is raw or after biogas digestion. The water recovery from the same shall depend only on its inorganic contents. For raw spentwash because of the higher values of the parameters, more membrane surface area has to be provided. Hence raw spentwash processing with the same 50% water separation shall need about 15% higher capital cost.

3. What can be the characteristics of water separated from raw spentwash?

The Rochem system shall remove about 98 to 99% of initial values of COD, BOD & TDS. The water separated will have that much lower COD, BOD & TDS. However, 50% water separated will be colourless.

4. Is it possible to increase the water recovery percentage from spentwash?

Yes. There are two ways to do so. First one can apply Rochem high-pressure system to the 50% concentrated spentwash remaining after separation of 50% water. Thereby another 30% water can be recovered. However, on account of its sophisticated nature, Rochem is not presently offering the same. Secondly, instead of reverse osmosis membrane process, Rochem offers Nanofiltration system, wherein the percent water recovery can go up to 70% from the spentwash. Operationally, the overall system is same, except the membranes are of different type.

5.What are the characteristics of water separated from spentwash using Nanofiltration?

The 70% water separated from spentwash using Nanofiltration has a very pale yellow tinge. It shall have higher COD, BOD & TDS compared to that obtained by reverse osmosis.. Accordingly, the water recovered in this manner, can be used for non technical operations like internal gardening, cleaning water or cooling water etc. or added to raw water tank.

4.What is the life of the membrane in Rochem system? What could be its replacement cost?

Rochem systems have a unique feature of cleaning in place (CIP) system, using which the preventive maintenance of the membrane has to be carried out to prolong the life of the membrane. After reaching some predetermined parameters of pressure & flow etc., CIP system to carry out the cleaning of the membrane to revive their characteristics have to be religiously carried out. This will prolong the life of the membrane. Secondly, being modular in nature, the positions of the membrane modules within a system can be altered or exchanged, thus replacing the membranes earlier exposed to higher TDS by those exposed to lower TDS. This will further help to prolong the life of membrane. Thirdly, the individual membranes sheets can be removed, inspected & subjected to cleaning if needed at all etc. This will prevent damage to the membranes. All these put together, for an application of using it for a notorious liquid like spentwash, Rochem system can be expected to have membrane life of more than 5 years. The replacement cost, which is never required in one single lot, because of the earlier explained features, is estimated at 0.9 paise per liter of spentwash processed. This is less than one paisa per liter of spentwash. Secondly it is a capital expenditure financed out of depreciation availed on the system. As regards giving a written guarantee, Rochem can give it only for one year, since life depends on so many factors of proper maintenance. However, if any party signs an operation & maintenance contract with Rochem, it can avail of the benefits of longer membrane life.

5. How the normally offered spiral wound membrane system differs from Rochem system?

The biggest difference is that no body shall give guarantee for spiral wound system for spentwash application! ! Technically, the configuration of spiral wound & Rochem system differ very widely. The spiral wound configuration provides very narrow path to the liquid being processed & cannot be cleaned & revived after fouling. These characteristics make spiral wound systems impossible to be applied to spentwash. If done irrespective of these factors, the membranes cannot be cleaned & may have to be thrown. Why there are no existing units using Rochem technology with spentwash application? Application for spentwash using Rochem system to separate good quality water was invented by Rochem in the year 2001 in India only. Spentwash arises only from distilleries operating on cane sugar molasses. There are no such distilleries in Europe, where Rochem developed their DT Module™. However, Rochem system is being successfully applied for a number of years in past to other applications, wherein it has to process even higher COD & TDS.

6.Considering it to be a new application, without any previous recorded use for spentwash, can Rochem give any guarantee to the prospective buyers?

Yes, of course. Rochem could be in position to give a performance guarantee of 10% value of the order valid for one year; if its system supplied for spentwash fails to produce the desired results, subject to proper up-keeping of the operating & maintenance parameters. However, it must be appreciated that 50% recovery of water is dependent on the characteristics of input parameters. Performance guarantee is only for an absolute failure, which will never happen.

7.What is the operating cost for Rochem System for spentwash application?

The operating cost shall consist of
(a) electricity cost
(b) chemicals & consumables required for preventive maintenance
(C) manpower cost.
The electricity & manpower costs shall vary. Rochem has assumed electricity cost to be at a level of Rs.4.50/ unit. Secondly Rochem assumes that the system require 4 operator with normal wages. (3No.for 3 shifts & one standby). Rochem has a standard assumption for chemicals & consumables for preventive maintenance. Accordingly, the operating cost will be 2.5 to 3 paise per liter of spentwash processed.

8.What kind of chemicals does Rochem use for preventing maintenance & membrane cleaning?

They are proprietary chemicals developed by Rochem for their chemical properties to suit the membrane material. They are to be purchased from Rochem to ensure well being of the membrane material. Use of any other chemicals are not recommended & Rochem is not responsible for damage, if any, arising from use of any other chemicals.

9.Can anyone purchase the membranes & cleaning chemicals directly from Rochem, Germany?

No. The collaboration agreement & financial participation of Rochem, Germany with Rochem, India does not allow any such arrangement. Secondly, the cheaper overheads in India enable the chemicals to be bought in India at cheaper rate.

10.What is the income tax benefit available for Rochem system?

Under Income Tax Act, different rates of depreciation are prescribed. The rates as applicable for Resource Recovery, Rochem reverse osmosis system applied to spentwash for recovery of water to be recycled is eligible for 100% depreciation, since water is a very well known resource, without which distillery cannot be run. Thus the investment in Rochem system will help judicious tax planning. It can be financed from out of funds, which otherwise would have been wasted in income tax payment.