On-Board Waste Treatment LECTRA/SAN MC
(formerly EC): USCG Approved Waste Treatment Device For Boats
The need for environmentally sound, pleasant, safe, and simple to operate on-board treatment systems has become clear in the last couple years. Despite the No Discharge Areas, passage of the Clean Vessel Act of 1992 and diligent enforcement by the USCG, State Marine Police, DNR and other bureaus, many boaters continue to dump raw sewage into our national and international waters. There will never be enough law enforcement officers to effectively enforce against illegal discharge from boat holding tanks. One strategy is to provide solutions to marine sanitation concerns in real world terms that preserves the environment.
To meet market need and demand, Raritan Engineering Co. has been working to make environmentally sound waste treatment systems that are easy, safe and pleasant to use. Raritan’s popular Lectra San MC (LST/MC) On-Board Waste Treatment Unit represents the easiest marine sanitation system to use. Flushing the toilet can automatically start the treatment process in just one step. With each flush sewage is treated immediately and automatically. No dangerous and/or offensive raw sewage is stored in the boat. Most boaters demand that marine sanitation systems be as easy to use as their toilets at home. As the needs of recreational boaters have changed, Raritan Engineering has responded with products that have solved many of the real problems with handling boat sewage.
Raritan Engineering Company, Inc. manufactures and sells accessories (appliances) for boats up to 75′ in length. Raritan Engineering Co. has demonstrated many innovative approaches to problems and market opportunities unique to the marine environment over the past 40 years. Through these successes, Raritan Engineering Co. has developed a very strong OEM and aftermarket customer base. Raritan Engineering’s expertise is marine plumbing; it is a leader in the field. Raritan has earned a worthy reputation through being quality conscious, responsive to market needs, and innovative. Anyone involved with large pleasure boats will confirm this.
Raritan Engineering Co. held patents for some of the earliest marine toilets for recreational boating. Raritan Engineering Co. responded to the need for treatment years before there was a Clean Water Act. Together, with Diamond Shamrock Corp., Raritan brought the first Type I MSD through USCG certification. Raritan Engineering Co. has continually reinforced its leadership role by providing improved technology for handling boat generated sewage for the past twenty five years.
The Lectra/San MC is designed to dependably treat sewage on-board boats. The process is simple, safe and pleasant to accomplish. It exceeds USCG Type I requirements and was granted Type I label certification. Certification followed extensive testing by a recognized laboratory in accordance with United States Coast Guard requirements. The evaluation involved rigorous electrical, mechanical and sewage processing tests. The Lectra San exceeded EPA requirements for effluent quality and eliminates coliform bacteria better than most municipal treatment plants. The independent lab test results required for certification documented coliform reduction in the sewage treatment process to less than 20 per 100 ml.
In 1997, a series of studies were undertaken by the Department of Veterinary and Pathology, University of Sydney, Australia. The test determined the effectiveness of the LST/MC’s (formerly EC) ability to destroy the hepatitis A virus (HAV). The lab test resulted in the following comments by the Virologist: this system is effective and will remove 78 – 98% of viruses from fecal material, as HAV is one of the most difficult viruses to destroy by chemical sterilization, a higher rate of removal for other enteric viruses can be expected when using this device.
The Lectra/San MC treats the waste in two distinct ways:
1. REDUCTION (maceration) of solid waste to indistinguishable particles,
2. OXIDATION of waste matter (destroys odors and bacteria) by hypochlorous acid.
The process starts with salt water in the treatment tank.
NaCl –> Na Cl- Sodium Chloride is a strong electrolyte so it
exists in water as sodium and chloride ions.
H2O –> H OH- Through hydrolysis, water breaks into hydrogen
ions and hydroxyl ions.
The electrode pack is energized during the treatment cycle and electricity passes through the conductive salt water. Hypochlorous acid, a powerful bactericide and oxidizing agent, is produced on the surface of the plates.
At the Anode:
2Cl- OH- H –> HCl HOCl 2e- Hydrochloric acid and hypochlorous acid are produced, liberating two electrons.
At the Cathode:
2e- 2 H 2Na 2OH- –> 2 NaOH H2 The two electrons, hydrogen ions, sodium ions and hydroxyl ions combine to produce sodium hydroxide and some hydrogen.
The Net Reaction is:
2Cl- 3OH- 3H 2Na –> HCl HOCl 2NaOH H2
With constant mixing from both motors, the products are mixed together for continued reactions.
NaOCl H2O –> NaOH HOCl Hypochlorous acid (HOCl) is formed when sodium hypochlorite reacts with water.
HOCl XXXX –> HCl XXXXOx Hypochlorous acid reacts with soil, dirt, and bacteria giving up its oxygen; leaving hydrochloric acid.
HCl NaOH –> H2O NaCl The hydrochloric acid reacts with the sodium hydroxide to form salt and water.
No external chemicals are added to the basic components of digested food, macerated paper, salt water and electricity. Waste is broken down through oxidation which is preferable to aerobic break-down because of the “friendlier” nature of oxidized waste by-products and the reduction of BOD. The hydrogen formed at the cathode bubbles off into the atmosphere. The water and salt by-products are eventually discharged into the receiving waters.
5. System Components
a. Treatment Tank
The three gallon (11.4 liters) treatment tank is divided into two chambers. The dividing partition contains the electrode pack with electrodes protruding into each chamber. The first chamber contains the macerator which reduces the sewage to tiny particles. The electrode pack produces the disinfectant which treats and disinfects the macerated sewage. During subsequent flushes, this macerated sewage flows through a cross-over pipe into the second chamber. The water must flow up and over into the second chamber which keeps larger particles in the first (macerator) chamber for further size reduction. In the second chamber, the waste receives further treatment and mixing before it is discharged. No sludge accumulates in either chamber when used properly.
b. Indicator Panel
The light-switch sized indicator panel contains a touch pad button for starting the treatment cycle and LED indicators labeled appropriately to indicate proper operation or the nature of a possible fault. When installed with an electric toilet, the toilet may be flushed at the same time the treatment is started for a simple one-touch operation.
When installed with a manually operated toilet (hand pump type) an optional pump sensor kit can be installed at the toilet which is wired to and automatically activates the Lectra/San MC’s treatment process.
c. Control Module
The control module contains a microprocessor control, logic circuitry and treatment monitoring capability to determine if the electrode pack is functioning, with variable condition automatic compensation control to ensure complete treatment every time. Power switching solenoids, fuse protection and a leaf shunt to measure current flowing through the electrodes are also included.
d. Salt Feed Tank (optional)
Three models are available: Two gallon (7.6 liter), Four gallon (15.2 liter) with automatic water refill, or Four gallon (15.2 liter) with automatic water refill and salt water injection.A concentrated saltwater solution is maintained in the salt feed tank. This concentrated salt water is metered into the suction line of the toilet or injected into the treatment tank when the water used in the boat’s toilet is not salty enough for the system to operate properly. The device is designed such that when using water near ocean salinity the salt feed tank will not be required. Brackish or fresh water flush requires additional salt to provide acceptable treatment and keep the unit operating correctly.
The Lectra/San MC is operated with the push of a single touch pad button switch. The treatment operation is automatic; the macerating and mixing motors as well as the electrode plates are turned on and off by the unit’s own timer control. Installations with hand pump toilets activate the LST/MC prior to pumping the toilet to flush or install the optional pump sensor kit which automatically activates the LST/MC while pumping the toilet. Installations with electrically operated toilets usually choose to utilize the automatic timed flush function built into the Lectra/San MC’s control. This allows the toilet to flush for a factory preset time of ten seconds insuring a clean bowl and lines without having to stand and hold a separate button for toilet operation. The operator may increase or decrease the length of flush by adjusting the flush time from one to twenty seconds. The LST/MC can also be activated from the special output of the Atlantes marine toilet. The LST/MC, used with almost any discharging marine toilet is the simplest marine sanitation system to operate correctly.
7. Flush/Pretreat Cycle
The toilet is flushed with the minimum amount of water to clear the bowl and line. Salt, if needed, is automatically drawn in from the salt feed tank. The flushed water and waste enters the flooded treatment unit displacing an equal volume of previously treated waste overboard. Only the mixing motor runs during the flush/pretreatment cycle. The flush/pretreat cycle lasts for about 35 seconds. At the end of the flush/pretreatment cycle, the control automatically switches to the treatment cycle.
8. Treatment Cycle
The macerating motor and electrodes are activated for the duration of the treatment cycle. The mixing motor also continues to operate during the treatment cycle. The hypochlorous acid disinfecting agent is generated at this time. The vigorous mixing action of the macerator and the mixer accelerate and enhance the oxidation of the waste and quickly destroy the bacteria and odor causing agents. The treatment cycle lasts for about two minutes but may run longer if the units regulating system must compensate for changes in voltage, salinity or water temperature. At the end of the treatment cycle, the unit automatically switches off.
The treatment tank holds about four flushes; the waste is therefore treated four times before being discharged. There can be no accumulation of gas inside the treatment tank because the Lectra/San MC operates completely filled with water. Lectra/San MC operates on standard 12 volt DC, 24 volt DC or 32 volt DC marine batteries. One and one-half (1.5) ampere hours of power are required for each two minute treatment cycle of the 12 volt units. The 24 and 32 volt units each require about 1.2 ampere hours.
The fundamental advantages of treating waste properly on-board compared to filling up and pumping out holding tanks or dumping raw sewage overboard are obvious to boaters and informed environmentalists. The ease of use and lack of visible, physical and odiferous contact encourage the user to use the system correctly and as specified. The treatment provided is safe, environmentally sound and easy to use.
Raritan Engineering has provided the best solution for handling on-board sewage on larger recreational boats by staying in contact with the market and responding to the changing needs. Further improvements in reducing non-point source water pollution; specifically boat generated waste will continue to come from the combined efforts of the boating public, legislators, law enforcement agencies and companies like Raritan Engineering.
*The basic outline of this paper and the chemical process follow the information provided in C.G. Parsons’ paper “Lectra/San -A Coast Guard-Approved Flow Through Treatment Device For Boats” printed in New Materials & New Processes Vol. 1 (1981), Diamond Shamrock Corporation.
Lectra/San is a registered trademark of Exceltec, 1110 Industrial Boulevard, Sugarland, Texas 77478 Telephone:(281) 240-6770
Raritan Engineering Co. Inc. is a registered user of the registered trademark Lectra/San.
Raritan Engineering Co. Inc., 530 Orange St., Millville, NJ 08322. Sales and service office 3101 SW 2nd Ave, Ft. Lauderdale, Fl 33315.