08.12.2019
Sewage and Waste Water Treatment

When we flush the toilet ashore, we do not have to bother about what happens next – the stuff disappears and this is someone else’s responsibility from now on. But that is not the case on board ship. To keep up treatment plant working properly everyone, not just the engineers has to understand what we cannot and what we cannot do with the sewage and grey water from the basins, showers and so on, which we produce. Everyone does not just mean ship’s crew – it includes anyone who comes on board, i.e. pilots, stevedores, even visitors from the shore office.

The reason we have regulations on how to deal with sewage is common sense, really. The stuff is not something you would like to have when your family is going to the beach for a day. What we are allowed to do with sewage is covered by the international regulations. The revised MARPOL Annex IV says there is no restriction on discharging sewage that passed through the approved treatment plant.

But, if your ship does not have an approved plant, as laid down in MARPOL, then you are not allowed to discharge any comminuted disinfected sewage closer than three miles to the nearest land. Even within that distance, it has to go into the holding tank, even if it has been through the treatment plant.

So, what does happen when we flush the lavatory and wash our hands? The waste goes to a treatment plant either using gravity and pumps or, in more modern systems, using a vacuum. Almost all treatment plants on ships work on what is called extended aeration. This simply means that air is blown through the sewage, which stimulates the production of the aerobic bacteria. Aerobic means existing in the presence of oxygen. Their job in life is to eat sewage.

In principle, this is how the aeration plant works. There are three compartments – aeration, settling and chlorine contact. Sewage flows or is pumped through a coarse filter to the aeration compartment and air is bubbled through series of diffusers. The air comes from low pressure compressors. The bacteria digest the sewage turning it into inert sludge, water, and CO2. Some of the sludge collects in the bottom of the compartment. The digested effluent together with the bacteria and the remaining sludge flow through another coarse screen into the settling tank. Sludge and bacteria sink to the bottom and recirculated to the aeration compartment.

Debris is skimmed from the surface. The clean effluent flows through a chlorinator into a contact tank. The chlorine kills any remaining harmful bacteria. Make sure you familiarize yourself with the local regulations. Some countries, Korea for example, insist on chlorination while others, such as Canada, forbid it.

Grey water from showers, sinks and so on, also flows into the contact tank and the resulting effluent which is now cleaned and harmless, is discharger overboard. The discharge is controlled by float switches located in the last chamber. The switches start the discharge pump which forces the fluid though a valve and overboard. There is an emergency overflow but it is very important to prevent sewage overflowing into the bilges because, if that happens, the oily water separator and the oil content monitor will not work.

This is the inlet filter on the front of the aeration compartment – it is a coarse screen designed to let human soil and toilet paper pass through it and nothing else. So please, no cigarette ends or packets, no condoms, no female sanitary products, no newspapers and no kitchen towels. Toilet paper is designed to dissolve, the kitchen towers are not.

Sewage and Waste Water Treatment - 3Grey water like sink waste does not go through the aeration process so there is one area in the ship where we have to be very careful – the galley. Too much grease can block pipes so those people who work here try to keep as much of it as possible out of the sink. Then, there is cooking oil. But there was a case in the United States when Port State inspectors sent down divers to investigate an oil spill on the ship in harbor – it turned out that someone emptied the entire contents of the deep fat fryer into the galley sink. If you need to get rid of the cooking oil, put it in a waste oil tank.

Of course, lavatories have to clean, too. Note that in the ship’s sewage treatment plant bacteria are our friends and not enemies. So we have to use special cleaners that do not kill aerobic bacteria. When you maintain your system, it is very important to inspect the outlet connection, particularly if your system uses vacuum technology instead of water and gravity to move the sewage the lavatories to the treatment plant. A break here on in any part of the piping will reduce the efficiency of the vacuum and has to be replaced.

There is another reason why this connection is important – it prevents any backflow of the sewage gases into the toilet compartment. But in case they do get in, it is essential to keep toilet and washing areas properly ventilated. Check extraction grills, louvers and ducts to make sure they are clean and not blocked with dirt; if there are fans installed, make sure they work.

The disinfectant tablets in the chlorinator also have to be checked regularly during routine rounds and their proper levels maintained. Make sure you keep sufficient spares as recommended by the manufacturer. From time to time the plant itself has to be cleaned and all build-up of sludge removed. Refer to the manual for the instructions. In principle, we shut the system down and empty it either partially or completely. We open up the compartments, inspect them and clean them.

We check the operation of the float switches and alarms, the condition of air diffusers and the compressor filters, belts and bearings. We replace any defective jointing. It is particularly important to check the compressors and the diffusers which supply air. If there is insufficient air, the aerobic bacteria die and are replaced by the opposite, anaerobic bacteria. They also digest sewage, but in the process they produce gases which are highly toxic, flammable and in some cases explosive – hydrogen sulfide, methane, Sewage and Waste Water Treatment - 4ammonia.

When you are cleaning the plant, do not go inside, wear the face mask, goggles and gloves at all times. Very rare, and in the really exceptional circumstances, when someone has to go inside the plant, remember that this is dangerous. Treated like any other entry into an enclosed space, do a proper risk assessment and take all the necessary precautions. Once the system is clean, you can re-fill and start it again and, as with any other maintenance work on board, keep a clear simple record of what you have done.

We normally clean the treatment plants when the ships Is drydocked or, sometimes, when in port. If cleaning is done in port, the sludge and the rest of the plant’s contents have to be discharge to proper facilities ashore. On rare occasions, we might have to clean the plant at sea because so long as we are far enough from land, untreated sewage can be discharged overboard. This is also an opportunity to use a bacteria killing cleaner so long as the system if flushed with sea water before the treatment plant is reconnected.

After starting the plant again, it takes between ten days and two weeks for aerobic bacteria to reestablish themselves. So, if you are cleaning it at sea, you must only completely de-sludge the system when the ship is going to be in unrestricted waters for that time.

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17.11.2019
Country Requirements Of Ballast Water Management

Here we will give you some brief introduction to the difference between regional requirements. Some countries have their own rules of ballast water management and these rules may differ from the ones of the IMO.

For example, before entering the United States exclusive economic zone, all ballast water shall be exchanged wither by sequential or flow-through methods. A special ballast water form shall be filled in and sent to the National Ballast Water Information Clearing House.

A special ballast water permit is required to trade in Californian waters. For the Great Lakes and Hudson River above the George Washington Bridge, a separate ballast water form has to be filled in.Country Requirements Of Ballast Water Management - 2

The Scapa Flow terminal on the Orkney Island in the United Kingdom is today the only terminal with facilities to receive all ballast water ashore. They have a capacity of forty thousand BBLS per hour.

Canada requires ships entering Canadian waters to perform ballast water exchange at sea, as far from land as it is practicable and in ocean depth greater than two thousand meters. In exceptional circumstances and for ships that have not left the North American Continental Shelf on the inbound voyage, the exchange may be made in internal Canadian waters within the Lawrence channel and in water depth exceeding three hundred meters. Such exchanges should be restricted to the areas South-East of 63 degrees West.

Argentine requires in-tank treatment by adding chlorine to ballast water through air pipes.

Australia is probably the country with strictest rules regarding ballast water management. They require following information to be recorded and saved for not less than two years: ballast water uptake locations given as a port of uptake or in longitude and latitude, identification of any ballast water tanks when the source of ballast water is unknown, ballasting start and end times, dates and volume of all ballast water taken on board, all Australian ports of intended ballast water discharge, date the ballast water is to be discharged in Australian ports or waters, time the ballast water is to be discharged in Australian ports or waters, ballast water being discharged – indicate whether it is a full or partial discharge, location where ballast water exchange took place, e.g. at sea, in deep mid-ocean, outside of Australian twelve nautical mile limit.

Country Requirements Of Ballast Water Management - 3In addition, you will need to confirm depth of water where ballast water exchange was conducted, e.g. 200 meters or greater, ballast water pumps used during the ballasting and de-ballasting operations, capacity of the ballast water pump per hour in metric tons, capacity and volume of the ballast water tank being pumped, time, duration for the ballast water being pumped to undergo full exchange, amperage or kilowattage of the ship’s generators prior to and during the ballasting operation, ballast water exchange percentage, date when the ballast water sea suction strainers were last inspected and whether they are in good order and prepared, records of damage and/or repair made to the ballast water equipment including ballast pumps, tanks, and piping etc. They also require all ballast water exchange to be recorded on a separate form.

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03.02.2019
Ballast Water Management Plan and Duties of the Ballast Water Management Officers

Let us try and get to some better understanding of the contents of a Ballast Water Management Plan. As per the IMO Resolution A.868, all ships must have a Ballast Water Management Plan. This Plan must include at least the following:

- Safety procedures for ship and crew associated with ballast water management

- Detailed description of ballast water management practices

- Detailed procedures for disposal of sediments

- Procedures for coordinating ballast water management with coast and port states

- Designation of ballast water management officer

- Reporting requirements

Please make sure you find the shipboard management plan and go through it very carefully. Two of the world recognized and authoritative organizations, Intertanko and ICS, standing for the International Chamber of Shipping, have compiled a model plan that can easily be applied to most of vessels.

Subject plan will cover the following topics, as necessary:

- Ship particulars

- Explanation of need for the ballast water management and reporting to port states

- Ballast water arrangements

- Safety considerations

- Procedures for managing ballast water

- Ballast water sampling points

- Crew training and familiarization

- Duties of appointed ballast water management officer

- Ballast water reporting form and handing log.

As per the above mentioned IMO Resolution A.868, all ships must maintain the appropriate records to ensure that the ballast water management and all treatment procedures are followed and duly recorded. These records must include at least the following key information:

- Date

- Ship’s position

- Tanks

- Ballast water temperature

- Ballast water salinity and amount of ballast water loaded or discharged

And now, let us talk a bit about the duties and training requirements for on-board personnel. In the ballast water management plan, a ballast water management officer is to be appointed. On vessels where the chief officer usually handles the ballast water operation, he will be appointed as the ballast water management officer. On vessels where an engineer usually handles the ballast water operations, he will most likely be appointed as ballast water management officer. The ballast water management officer has the following duties:

- Ensure that the ballast water treatment or exchange follows procedures of the ballast water management plan

- Prepare the ballast water declaration form prior to arrival in port

- Be available to assist the port state control or quarantine officers for any sampling that may need to be undertaken

- Maintain the ballast water record log.

All personnel involved in ballast water handling must have adequate knowledge about ballast water management. This knowledge can be achieved by practical training on board or through the computer based training. The duties for each crew member involved in ballast water management you can find out by asking your ballast water management officer.

All officers and crew involved in ballast handing shall receive training in the following topics:

- The reason for exchange a ballast at sea

- The two main methods of exchange, namely flow-through (simultaneous filling and overflow of ballast water) and sequential(discharge and refilling of tanks)

- The means of carrying out ballast water management on board

- The reason why other means of ballast water management should not be used on board

- The location of sampling points

- Methods of sediment removal to be employed and how frequently it should be carried out

- The contingency procedure for situations that may affect the safe ballast exchange at sea to be explained.

This article was supposed to provide readers with the very basic introductory information about the Ballast Water Management Plan and the duties of the key shipboard personnel engaged in the ballasting operations. You are definitely invited and encouraged to go through the content of the training materials available here, including books, training videos and regulatory documents. As stated above, every single person involved in these operations in any way, shall possess sound understanding of the process since this is a key point for provision of the safety ballast handling operations and avoiding pollution to the marine environment.

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04.11.2018
Ballast Water Management Methods

Let us talk about various techniques used for treating ballast water. Limiting the amount of ballast taken is the first step in an effective ballast management plan. Practices that minimize the intake of port and coastal sediments can also be effective in reducing aquatic introductions. Ballasting should be avoided in very shallow waters, in stagnant areas, in the vicinity of sewage outflows and dredging operations, in areas where known pathogens are present etc. Whenever practical, the loading of ballast water should be delayed until the ship is in open ocean waters.

Ballast water exchange is currently considered the single most practical method for ballast water management. Ballast water exchange can be accomplished by either the sequential empty-refill method or by flow through, also referred to as the overflow method. It has been reported that these methods are about 95% effective in eliminating aquatic organisms. Ballast water exchange operations should be performed in deep water away from coastal shelves and estuary influences.

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27.05.2018
What Is Ballast Water?

Generally, ballast water is water carried in ships' ballast tanks to improve stability, balance and trim. It is taken up or discharged when cargo is unloaded or loaded, or when a ship needs extra stability in foul weather. When ships take on ballast water, plants and animals that live in the ocean are also picked.

In this article we will try to give some small background to the ballast water management which is becoming an issue of higher and higher importance to the protection of the marine environment. International shipping has been identified as one of the key pathways for the movement of species between different eco systems. Organisms and pathogens found in the ballast water and sediments in ballast tanks have significant economic and ecological impact on marine biodiversity in many regions.

They can also potentially pose a serious threat to human health from the spread of diseases and species harmful to humans. Unlike some forms of ship-sourced environmental harm, the problem arises from the activity inherent to ship's operation. Currently, there is no entirely satisfactory means of preventing the transfer of species in ballast water.

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