1: Design Considerations for Permanent Sewage Pumpouts in Today’s Marinas By: Marty McDonald HDB Marine 888.689.3248 HDBMarine.com

Sewage pumpout systems are a necessity in today’s marinas.

Law – the majority of boats are equipped with sewage holding tanks (they have options of having their own sewage treatment units aboard)

Full service Marinas provide pumpout equipment to removing the sewage from the boats and disposing of the sewage in accordance to State and local sanitation codes. (1) discharge to a public wastewater collection system and treatment facility (2) discharge to a holding tank with removal and disposal by a licensed septic hauler (3) discharge to an approved onsite septic treatment plant

Types of sewage pumpout systems – Marinas

A. Fixed Point of Pumpout

This is the most common – a fixed pumpout station is located at a fuel dock, dock-end, or dedicated area

FUEL Dock Locations – special consideration must be given to the equipment when used on a

fuel dock –must comply with National Electric Code (NEC). Requirements include explosion-proof motors and controls and more. With Today’s equipment A great solution – is to locate the pump equipment away from the fuel dock and use remote stanchions with wireless on/off control to the pump (this eliminates all electrical wiring at the stanchion.

2:

Pumpout Stanchion with Wireless battery control ON/OFF eliminates electrical wiring and risk of spark in Fuel area.

It is not necessary to mount the pump at the site of service. Remotely stationed pumps may be preferable when service areas are congested with other equipment. Service points of up to 1000 feet can be accomplished when properly designed.

A single pump may serve multiple pumpout point in the pumpout area. Users must be attentive about fully closing the vales at each location. Some marinas choose to install indicator lights to identify which units are in operation.

B. Slip side Pumpout Service The fastest growing trend in sewage pumpout design for marinas is providing pumpout service at the boat slip location.

Larger marinas – faster service, eliminates congestion at the fixed Point of Pumpout, better service for customers (boaters now demand this service)

Pumpout hydrants are located along the dock so that two or four boats may be serviced from the hydrant. Generally a hydrant is located at every other berth location. Linear docks with side-ties may locate the hydrants on 80’ or 100’ centers along the side of the dock.

3:

Pumpout Hydrants located to service two boats

A growing trend among pumpout manufacturers is to service the hydrants with peristaltic pump systems with Wireless remote ON/OFF controls. The pump may be located remotely for aesthetic or design preferences.

4:

Pump unit equipped with Wireless ON/OFF controls – located 200’ away from the docks – by the sewage disposal point

Two pumpout units – located behind shrubbery for aesthetic purposes – one pump services 1200’ of

dockage/hydrants – second pump service 1800’ of dockage/hydrants –pumps are operated by Wireless

remote control system –pumps have a common manifold system so that each pump can serve as backup

for the other.

5:

Sewage piping – materials and design considerations

Most of us understand that in residential applications – sewage flows downhill.

However, that is not so with sewage systems in marina applications. It is critical to understand that

sewage piping in marinas is either under pressure or is handling a vacuum within the line. It is important

to determine the right type and size of piping for the sewage system for a marina.

We recommend that the marina engaged the services of an engineer or qualified plumbing expert.

Design considerations are based upon:

State and local code requirements

Suction Lift – vertical distance from the bottom of the onboard holding tank to the inlet of the dockside pump

Discharge Head – vertical distance from the outlet of the pump to the point where discharge terminates into a sewer, manhole, and holding tank or lift station.

Physical requirements of the dock design, property layout, and goals

Engineers evaluate the in-line velocity through the piping, pressures within the pipe, flow rate with respect to scrubbing or potential buildup within the piping, friction loss, and much more. Engineers will use this information to:

Size the piping

Size the pump Often times, marinas on inland fluctuating lakes are faced with extreme discharge head requirements that will require lift stations and Flood design considerations. Special expertise may also be required where sewage lines are to be installed underwater. Flex lines that run underwater can cause “hammering” or noise by trapping air within the line. Pipe Materials & Design The sewage pumpout system in a marina is only as good as the plumbing lines. Plastic piping is the norm for sewage piping in marinas. Advantages:

Lightweight

Resistance to corrosion

Easy to handle and install Areas of concern:

Must allow for thermal expansion or contraction in pipe length

Avoid vibration and wear points that will cause holes or weakening

UV resistance? Some codes require schedule 40 PVC to be painted if exposed to the sun

6: Two Types of Plastic Piping

1. Polyvinyl chloride piping (PVC) – glued joints, 20’ maximum lengths, Schedule 40 may be applicable in simple or small applications. Schedule 80 is preferred because it is UV resistant and more rugged and dependable than schedule 40. Special care should be given in properly cutting, cleaning and gluing of the PVC joints. While there is a type of industrial Fused PVC, it is not seen in marina applications.

2. High-density Polyethylene piping (HDPE) – welded/fused joints, 1000’ maximum length, flexible yet rigid, can heat and bend as required. Installed with fewer joints, properly fused joints are as strong as or stronger than the pipe itself and are leak free. HDPE is the material of choice for many plumbing contractors.