Sludge Watch ==> Maryland - contentious community drip irrigation wastewater plan

[Maureen Reilly]

Drip irrigation sewage systems rare in Maryland
By Katherine Crowell
Staff Writer


SALISBURY -- Dozens of local residents are building a case against a drip 
irrigation sewer system proposed for a subdivision off Riverside Drive 
Extended, but one of the problems they face in learning about the system is 
the lack of examples in Maryland.

Only one drip irrigation sewer system operates in the state in Calvert 
County. The system supports the Marley Run subdivision in Huntingtown, but 
the treatment process has been unable to meet the water quality standard set 
by the state, officials said.

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A drip irrigation system works by putting wastewater from all the homes into 
a common collector. The wastewater generated per day goes through a filter 
system and passes into the ground through a network of pipes spread out 
across several acres of land and buried a few inches below the ground.

Marley Run
The Marley Run wastewater system was issued a groundwater permit for a drip 
irrigation sewer in August 1998 and has been operating since December 2001. 
The system handles up to 15,000 gallons of wastewater per day for 53 homes. 
The subdivision is planned to have 100 homes and the system's maximum 
capacity is 40,000 gallons per day.

The cause of the problem with the system hasn't been determined, but one 
possibility is a chemical compound released during the treatment process 
that is preventing the wastewater from reaching the required water quality 
by killing the necessary microorganisms that essentially eat up pollutants, 
said Barry King, utilities bureau chief for Calvert County. Marley Run uses 
a fixed activated sludge treatment, or a trademarked treatment that combines 
three biological processes into one tank as opposed to using separate tanks. 
The problem might also be related to extreme temperatures in the winter and 
summer because these systems are often susceptible to weather-related 
conditions, he said.

Even though there are problems with the treatment aspect, the drip 
irrigation discharge process has been working fine, King said. The quality 
of the wastewater is still better than it would be if a conventional septic 
system was used, he said.

"The concept is sound with the irrigation system," he said. "The ultimate 
goal here is to improve the waterways of Maryland and Virginia. One of the 
primary components is going to be a reduction in the number of conventional 
septic systems used, especially if we're going to continue growth. There's a 
trend away from the conventional septic system."

Robert Ballinger, spokesman for the Maryland Department of the Environment, 
said the agency is working on a legally binding document that sets up 
procedures and regulations they expect the overseer of such systems to 
follow in the future. In the case of Marley Run, MDE is working with Calvert 
County to make a schedule for fixing the problem.

"We were concerned and certainly want them to function properly," said 
Ching-Tzone Tien, chief of MDE's groundwater permitting division.

Conventional septic vs. drip irrigation systems
Localities throughout the state are grappling with this emerging technology, 
Tien said.

While drip irrigation has been used for farming landscapes such as orchards 
and gardens to supply water to fruit trees and flowers for a very long time, 
it is a relatively recent alternative for treating and disposing of 
wastewater, he said. Subsurface drip irrigation started becoming a popular 
alternative in the mid-1990s to late 1990s, he said.

"It is a fine treatment system," Tien said, referring to the system's 
ability to treat wastewater to a very clean quality.

There are significant differences between the conventional septic drainfield 
systems and the drip irrigation system, including the higher cost of a drip 
irrigation system, he said. The cost combined with the fact that it is 
fairly new technology are the main reasons why only 11 drip irrigation 
systems have been proposed in the state thus far, Tien said. One of the 
proposed permits under review is the hotly contested Reagan's Run, a 58-home 
subdivision off of Riverside Drive proposed by Greg Tucker of Tucker Homes 
LLC.

The conventional septic drainfield system is made of disposal pipes buried 
deep in the ground, sometimes more than 10 feet, where the most permeable 
soil is located. Nutrients are not absorbed by crops above ground and the 
system is not subject to freezing and no storage pond is required. The 
wastewater loading rate for the conventional system is between .8 and 1.2 
gallons per square foot a day.

Drip irrigation systems are built by disposal tubing buried just a few 
inches below the surface, and grasses are used to absorb and remove 
nutrients. The system can be affected by adverse weather conditions like 
freezing, and a pond is required for holding effluent during bad weather 
conditions. The wastewater loading rate is .18 gallons per square foot per 
day, but requires more disposal area than a drainfield system.

The best system for a particular development is determined by the site 
conditions, Tien said.

"If there are permeable soils and a deep water table, a conventional 
drainfield system is a more cost effective system," Tien said. "If the water 
table is shallow and soil is not as permeable, the shallow drip system is 
more feasible."

Reagan's Run
Last month, Tucker submitted an application to MDE for a permit to construct 
a central drip irrigation system on the site located at 27791 Riverside 
Drive. The septic discharge would disperse a maximum of 18,525 gallons of 
wastewater a day.

Because of high citizen concern in this case, a public hearing will likely 
be announced by MDE, Tien said.

Tucker has hired engineers who specialize in wastewater treatment systems to 
determine whether the site can handle a community drip irrigation sewer 
system and the results of their analysis thus far has been that it can 
because the sandy soil is permeable and the water tables are in the 2-foot 
to 5-foot range. This type of wastewater treatment system would allow Tucker 
to build twice the number of homes compared to if he complied with what's 
typical of the neighborhood -- individual septic tank systems.

The Reagan's Run system is in the very beginning phases since the permit was 
applied for in July and has not been designed yet. The irrigation field is 
proposed to be 7.8 acres and will have the required reserve area, in case 
the system does fail at any point.

Craig Goodwin, general manager of the Seattle based engineering firm NCS 
Wastewater hired by Tucker, said failures he's seen in systems throughout 
the country are usually caused by design or installation problems. The 
tubing must be distributed evenly with the contours of the soil.

One of the many other concerns residents have is who will have to foot the 
bill in case anything goes wrong and the system fails or needs major 
repairs. Tucker, as the permittee, is responsible for monitoring the system 
according to the standards yet to be set by MDE, or he can contract the job 
out to a private business.

Rai Sharma, director of Wicomico County Public Works, said at a public 
meeting recently that the county, while it acts as the governing authority 
over the development, will not be responsible for maintaining and monitoring 
the site. That job is likely to be contracted out to a private business and 
paid for through a monthly fee by the subdivision's homeowners association.

"This is not going to be a shared facility," Sharma said. "It's going to be 
a community facility. A company will handle this, not the county."

kcrowell at dmg.gannett.com

410-845-4655
http://www.delmarvanow.com/apps/pbcs.dll/article?AID=/20070107/NEWS01/701070317/1002