Contents

Sewer Televising

New Digestor Cover
Saves Money

Leak Detection for
Water Systems

Wesleyan Church of Hamburg Phase III

We currently have equipment and trained technicians for the inspection, by color television camera, of sanitary and storm sewers as well as service laterals to check for obstructions, leakage and breaks. If your sewer system has infiltration and/or inflow problems we can help you find the sources.

We can also provide videotape logs for future reference or use in confronting sewer ordinance violators. Logs are captioned and have date, time and footage. On-tape narration can be provided if desired.

Using our sonde locator, we can physically mark the ground surface to show location of and depth to pipe defects.

The equipment is capable of inspecting pipe from 4 inches to 36 inches in diameter. In certain cases we can also check interior piping down to two inches in size.

Our equipment is very compact and can be removed from our truck to a remote off-road project site if necessary. Other conduits (electrical, telephone) and even chimneys can also be inspected.

Complementing our televising equipment is our smoke testing machine. Our technicians can help locate improperly constructed sewer connections, inflow and infiltration sources using the machine to pressurize smoke into the pipelines. Digital photographic documentation can be furnished along with location sketches.

We recently completed a storm sewer system TV inspection of 18,000 linear feet of 12 inch to 72 inch pipe, a 1200 foot reach of 6 inch sanitary sewer and a 450 foot run of 8 inch sanitary sewer. The camera videotaped all the sewers and documented pipe breaks, joint leaks, root intrusions and obstructions to flow.

New Digester Cover Saves Dollars
by Jeffrey C. Bahret, P.E.

Back in our Spring 1998 Newsletter, we reviewed a new design of anaerobic digester covers for wastewater treatment plants. This new cover design (Dystor System), is primarily used in replacement of the old rigid floating covers. The rigid floating digester covers are limited in their ability to store methane gas for heating the sludge contents. They are also prone to tipping and binding within the digester tank which can not only damage the cover, but also the internal piping within the tank.

A key problem with these traditional rigid floating covers is simply their advanced age. After about 30 years of being in the corrosive environment of organic acids and methane /carbon dioxide/sulfur gases, the carbon steel used in the covers construction is no longer structurally sound. The corrosion is typically so pervasive that rehabilitation is not cost effective. Hence, the owner is left with the replacement option only, when considering a structurally deficient cover. Fortunately, we are no longer bound by the old rigid steel cover design, as material technology has advanced in recent years to enable a new flexible membrane design to emerge.

The Dystor system is a gas holder design that uses a dome-shaped, engineered membrane system to store methane gas for use, provide for additional sludge storage and prevent odors.

The Village of Springville wastewater treatment plant’s primary digester was retro-fitted for a new flexible gas holder cover (see photo), and went "on-line" June 1, 1999. This was the first of its kind in New York State. The retro-fit included modifications of the digesters ring wall and replacement of interior/exterior piping systems. One item which makes this installation very unique, is that the primary digester was fitted with two 18 inch diameter "bubble-canons" in the mid-80's. They act like large positive displacement pumps, using large methane bubbles as pistons. These mixing devices mix the sludge very efficiently at a combined rate of 2,400 gallons per minute. This turbulent liquid surface activity was accounted for in the design of the new cover system and has not caused any problems.

We are now operating within our second winter since the new cover installation. We can, from the data collected to date, make the following conclusions:

Severe winter weather (sustained freezing temperatures and heavy snowfall) has not caused any problems with the system.

The 50% increase in available sludge storage created by this cover installation has helped day-to-day operation practice.

The better mixing environment has increased methane gas production by 22%.

The 1,000 percent increased gas holding storage has reduced the amount of gas wasted (burned off) by 77 percent.

And the major item; The amount of natural gas purchased to supplement the methane gas used to heat the digester sludge is down 51%. This equates to an annual savings of approximately $5,000 per year at present natural gas prices.

Leak Detection for Water Systems
by Tom Reed, J.D. Northrup Construction Co.

In these days of increased costs and shrinking municipal budgets, sometimes very useful tools for managing these costs are overlooked. Feeling the budget crunch along with other municipal departments, the water departments have had to come up with new ideas and procedures to insure that their water systems perform smoothly and efficiently, thereby maintaining projected budgets and preventing unanticipated costs in some items from diverting funds from scheduled maintenance or needed system improvements. To operate effectively within its established budget, the water department must monitor very closely and struggle to control its unaccounted for water losses. Some losses, such as meter slippage, can be adjusted by estimated percentages and unmetered use can be periodically estimated and factored in, but the most budget damaging losses can be those attributed to leakage. This loss must be identified as quickly; followed by the necessary steps to pinpoint and repair.

So, what is a leak? This could range from a dripping corporation stop to a flexure break in ductile cast iron. Many of these leaks may actually have been initiated during construction and have grown larger as a function of time. Others may just happen after 50 years of service.

One of the most effective tools that the water department can utilize to control this unaccounted water loss is a defined leak detection program which may be implemented in a number of steps. These steps are briefly outlined below:

Periodic monitoring and comparison of production or supply meter readings. These meter readings should be recorded and analyzed on a daily basis to establish daily production or supply requirements. These requirements can then be compared to past, same period requirements, to determine if usages are average and normal or if a possible leak has occurred.

Overall water system survey. Once it has been established that a leak problem does exist within the system the next step is to localize the area where it exists. This may be accomplished by using isolation valves and monitoring the supply meter until the local area of the problem is known; or by using a relatively simple listening device to survey the access points (hydrants, line valves, service valves) to determine where leak sound is present.

If the leak fails to surface, which many do not, or if there are no indicators present to pinpoint the exact location of the leak, a computerized leak detection system can be used to pinpoint the exact location of the leak to facilitate repairs.

The computerized leak detection system mentioned utilizes the sound generated by the leak itself to pinpoint its exact location. This is accomplished by bracketing the leak sound at available access points with listening devices/transmitters and relaying this sound to a specialty computer which, can then compute the exact location of the leak. This acoustical analysis can usually locate the leak within 1 to 2 feet, and is a very cost effective means of locating leaks in areas where they do not surface, or where it would be cost prohibitive for exploratory excavation.

It is highly recommended that the every water system be electronically surveyed a minimum of once every three years. This is to eliminate those small leaks that very gradually increase the unaccounted for water losses. This complete survey, after all leaks are located and repaired, establishes a system reference base point to which later comparisons can be made to judge overall system performance.

The cost of a complete system leak survey, whether done by in house personnel or by an outside firm, can be easily justified since payback has been shown to occur usually in less than four months.

A few examples of survey results are:

Bradford Water Authority, Bradford, PA water system survey June 1993, 41 leaks were located for repairs with an estimated daily loss of 1,200,000 gal/day.

City of Tonawanda, NY water system survey April 1993, 36 leaks were located for repair with an estimated daily loss of 630,000 gal/day.

City of Tonawanda NY water system survey April 1999, 40 leaks were located for repair with an estimated daily loss of 640,000 gal/day.

In comparing completed surveys for the City of Tonawanda, NY, one in 1993 and another in 1999, it is very apparent that leak detection must be a continuous, never ending process in order to maintain an efficient, safe, cost effective water system.

Wesleyan Church of Hamburg Phase III
by Garrett M. Hacker, E.I.T.

The Wesleyan Church of Hamburg Phase III Worship Hall addition, Erie County, NY is closer to completion. Huff-Morris Architects of Richmond, Virginia heads the 12.5 million dollar project and design team consisting of Wilson, Klaes, Brucker & Worden, P.C. (Mechanical, Electrical and Plumbing), Siracuse Engineers (Structural) and E&M Engineers and Surveyors P.C. (Civil).

E&M provided comprehensive design and technical services including the following: property and wetland boundary and topographic survey, site design, deceleration and acceleration lane addition to McKinley Parkway and onsite soil inspection during construction phases.

With the high volume of traffic during a typical Sunday morning, traffic flow throughout the site was a high priority. The existing McKinley Parkway entrance drive was removed due to its close proximity to the Bayview, Sowles, McKinley intersections and moved north allowing for safer egress. The new entrance drive consists of three lanes enabling stacking of vehicles within the site and a designated turning lane. To minimize traffic disturbance on McKinley Parkway deceleration and acceleration lanes were added to the south bound lane.

To utilize the entire site, an existing drainage ditch collecting storm water from an upstream 350 acre residential watershed was channeled through three 36-inch culverts bisecting the site and discharging to Rush Creek. Onsite storm water runoff is controlled through a network of precast concrete drainage inlets and smooth bore high density polyethylene pipe. Channeled runoff is then directed to one of two onsite detention basins. During small storms (2-5 year recurrence) water bypasses the storage basins via a 6-inch diameter pipe and directly discharges to Rush Creek. However, larger storms (10 year recurrence and higher) are restricted by the 6-inch pipe and begin to fill the basins. By detaining only large storms, the church was able to utilize this area for volley ball and other sport related activities.

Kirst Construction of Boston, NY (General Contractor) anticipates a Spring of 2002 completion.