10. Course of action

10.1. Objective 1

10.2. Objective 2

10.3. Objective 3

10.4. Objective 4

10.5. Estimated investment costs and returns on capital

What must we do to recover the losses that result from the discharge of these materials, will the recovery be cost effective and will there be a relatively quick payback of the capital investment. Or are we better off installing a marine outfall pipe and sending everything back to the sea?

10.1.1 Install evaporation plant

From Figure 45 we see that the major source of yield loss and pollution is the loss of the stickwater. Stickwater contributes about 48 kg of dry solids per ton of fish landed or about 19% of the dry matter in the fish. There is a very quick payback when an evaporation plant is installed. There are other considerations, however. The increased dryer load by the addition of the stickwater concentrate could require more dryer capacity. If the raw material is of poor quality, then the volatiles in the water will evaporate and come out in the condensate water and some will carry over into the meal. If the factory does not have steam dryers, the evaporator cannot take advantage of the available waste heat and it would be necessary to add additional boiler capacity. There are opportunities also. In the 1960's, in North Carolina USA, five companies operated fishmeal plants for a relatively short fall season (8-10 weeks). Much of the equipment for these plants was installed for the season by relocating it from factories whose season was over. None of the plants had stickwater plants so the pumpwater, blood water and stickwater were discharged overboard. A new company formed to handle these waters. Evaporators and tanks were installed and an arrangement was made to pickup the water for processing with no cost for the mateiral. A market was developed with companies that took the concentrate and dried it back on vegetable carriers such as alfalfa, soybean meal, and wheat. This new product began to compete with the fishmeal because it was cheaper and eventually the fishmeal plants began to add the solubles back on their own presscake. Most of the factories in that area are now closed but that was the start of wholemeal production in the USA. In Peru, several factories could join together, install and operate an evaporation plant and recover what they are jointly discharging. Or a new company could form to handle this valuable material. If there is no evaporation plant, recovery of the blood water will not be done as it is necessary to evaporate the blood water to recover all the solids so the losses are even higher.

10.2.1 Eliminate or redice water in the unloading process

Pumpwater is the next major source of yield loss and is almost on an equal footing with the stickwater. The pumpwater is further complicated by the fact that: (Figure 46)

1. The source of the water is sea water so there is a very high salt content
2. The volume is very large
3. It is generated in a very short period of time
4. It can contain large amounts of solids and fat.

There may be other issues but these should be the major ones.

We can solve the salt problem by using fresh water if it were available, but it is our understanding that most of the fresh water wells would go dry or there would be salt water infusion into the wells if that volume was removed (Figure 47). For our 50 ton/hour plant we are talking about a minimum of 200,000 cubic meters of water over the season but during the typical unloading operation this could be 400 cubic meters per hour. For all of Peru, the volume of pumpwater should be 16.8 million cubic meters over the season. Another way to eliminate the salt problem would be to go to vacuum unloaders. These unloading systems use air instead of water. A small volume of water is used to seal the valve and for cleanup but other than that there is no water. Vacuum unloaders cannot move the fish the distances that are needed in Peru. In order for the vacuum unloader to work properly it would be necessary to either build a pier out to the unloading station and dry convey the fish to the plant or to install the unloading operation in the City's port so that the vessels can come alongside the dock. It would then be necessary to move the fish to the factory by truck. The dry unloading operation has the advantage that you no longer will worry about yield losses in the pumpwater or long range effluent limitations. But the systems are expensive and the payback might be five or more years.

If we don't have a sufficient volume of fresh water and dry unloading is not practical, we should look at reducing the volume of water. We can reduce the volume of water by going to dry pumps or semi-dry pumps. There are several pumps on the market being used here in Peru and Chile, as well as in other parts of the world. The current pump being used throughout the fishmeal industry here in Peru uses at least a 2:1 ratio of water to fish (this might be as high as 3.5:1).

The pressure/vacuum pump is being used in Chile and several are now being installed in Peru. The pump operates on a ratio of 1:1 and this would reduce the volume of water by a factor of 2. In some cases and with some species of fish the ratio can be reduced. There have been some questions about whether the pump can unload 200 tons/hour and move the fish the required distance (1000-1500 meters). We have no data on the composition of the pumpwater generated by this pump at this time.

The Netzsch pump operates on a ratio of 0.5:1 and this would reduce the volume of water by a factor of 4. This pump is being used in Peru but there have been problems with it. It is very heavy and difficult to move and the capacity is not sufficient for the larger factories. At this point we have no data on the pumpwater from this pump but hope to have it at some time.

The Myrens pump is used in Iceland and Norway. It is a dry pump that operates on a ratio of 0.1:1 and would reduce the water volume by a factor of 25. The Myrens pump is also used to move fish within the factory so that conveyors are not needed. In Iceland they use some of the blood water to start the unloading process. The pump is suspended from a crane and lowered into the hold of the vessel or it can be mounted on the vessel. The pump may not be able to move the fish the 1000-1500 meter distance that is necessary, so it was recommended that three pumps be used in series to move the fish that distance.

If we can reduce the volume of water sufficiently, then we might be able to change over to fresh water or at least process this reduced volume of water.

Recycling of the pumpwater is used in the USA, and some factories in Chile. In the recycle process wet pumps are used at the normal ratio of water to fish. The pumped fish are transported to the factory where the water and fish are separated and the fish are measured or weighed. The pumpwater is then screened through 1 mm screens and collected in a feed tank for recycling back to the vessel. The process is continued until the water is too thick or the vessels have been unloaded.

Recycling (Figure 48) offers several advantages; any system can be retrofitted, the solids buildup is constantly recovered, it uses much less water (in the USA the ratio is about 0.3:1 water to fish) which can then be evaporated. There are some precautions that must be taken in the recycling to prevent the formation of gases, and fresh water must be used to eliminate the salt problem. Depending upon the plant configuration, it might be possible to utilize a waste heat evaporator to concentrate the pumpwater instead of a second evaporator. Figure 49 shows a typical recycling system that might be used in the Peruvian fishmeal industry.

10.3.1 Recover solids from the reduced volume pumpwater

From the literature (Figure 50) and tests in Pisco (Figure 51) we have found that screening the water through 1 mm screens will only recover about 38% of the solids in the pumpwater. Finer screens might be able to recover more, but will not recover the dissolved solids that are in the pumpwater.

The fishmeal industry has experimented with dissolved air floatation (DAF) and dynamic air floatation (DYAF) as a way to recover solids and fat from the waste water streams. DAF involves injecting micro bubbles of air into the screened water so that fine solids and oil are floated to the surface and skimmed off. The water is then discharged and the solids/oil mixture further processed. Using the DAF system instead of a fine screen and then recycling the water back to the vessel, might be another way to reduce water and recover solids. The final water can then be screened or processed along with the stickwater. It should be pointed out that DAF will not remove dissolved solids. Studies have been done over a very long period of time to use coagulating chemicals to recover some of the dissolved solids but then you must deal with the chemicals and the regulatory issues that govern their discharge.

For plants that have operating stickwater plants, the easiest way to recover all the solids from the reduced volume pumpwater would be evaporation. Evaporation is not an option if salt water is used for pumping the fish since the salt content of the water would be further concentrated almost to brine. This brings us back to the fresh water issue. If we can reduce the water volume sufficiently, then it might be possible to utilize fresh water with a recycle system.

10.4.1 Recover the blood water

Bloodwater is the liquid produced during storage of the fish. It is made up of blood from the raw material, some fish solids, plus seawater found in the fish and some pump water. The composition of the bloodwater will vary with the composition of the raw material and the length of time that the fish are stored before processing. The bloodwater is usually added back to the process to recover the nutrients and to avoid pollution problems (Figure 52). The process usually includes a heating step to 7-80 centigrades to coagulate the protein followed by a centrifuging step to remove the coagulated solids and oils. The resulting liquid is then added back into the stickwater and evaporated. The solid fraction usually goes to the presscake line for drying and the oil, normally dark and of poor quality, is either held separately and sold at discount prices or mixed with the fuel oil and burned.

The recovery of the bloodwater is a major step in improving yields and reducing pollution. The quality of the nutrients in the bloodwater will vary with the quality of the raw material at the time the fish are unloaded and their deterioration during storage in the factory. Based on the limited sampling of the bloodwater in the Paracas plants it is difficult to place an exact value on the recovery of the nutrients. Samples were taken from fresh and spoiled fish. In one case, the solids content of the bloodwater was 60% (spoiled fish) and in others as low as 4% (very fresh fish).

Based on the data that was received, you could expect to lose between 0.5% and 6.2% of the processed blood water as protein and fat depending upon the condition of the fish. Since there was no actual volume measurement of the blood water, it was not possible to relate these figures to the tons of fish landed. The data does indicate however, that once the bloodwater has been coagulated and separated, there is still about 76% of the nutrients in the liquid phase. If the liquid phase is discharged as effluent instead of evaporating it with the stickwater, then the major part of the nutrients are being discarded. The proteins in the bloodwater appear to be soluble and are not being coagulated by the process being used (Figure 53). Evaporation would seem to be the best route to recovering this material.

We've now identified the potential problem areas, defined the challenges and offered options to meet the challenges and improve returns by increasing yields. But what are the estimated costs and the payback to recover the capital investment. It isn't possible here to go into a complex return on investment analysis for Peru, but we can estimate the capital cost and calculate how long it will take to recover that investment with product. Figure 54 outlines the various optional technologies and groups of technology that have been described. In Figure 55 we list the various combinations together with their capital cost, amount of fishmeal that can be recovered, its value and the time it will take to recover that capital. It does not take into account operating costs and maintenance.