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Dear Mr. Scott Davis [President, RBS] As per your request the following is a report on sludge disposal using the Phragmites reeds at The Beverly Sewerage Treatment Plant located in Beverly City, NJ. The Beverly Sewerage Treatment Plant services the City of Beverly and the Township of Delanco. The treatment plant deign flow is 1.0 MGD , however the actual flows are less then 0.500MGD, The treatment process is Anaerobic, Primary Settling (Imhoff tanks) followed by High Rate Trickling Filters, Secondary Settling and chlorination with the final effluent discharged to the Delaware River. Anaerobic Sludge is removed daily from the primaries at 2 to 3 % solid and is draw into primary holding tanks where the sludge is decanted and the solid concentration of the sludge can increase by as much as 5 to 7 % before being transfer to secondary holding tanks. Sludge in the secondary holding tank is anaerobically digested with a minimum retention time of 15 days, The solid concentration of the sludge removed from the secondary holding tanks therefore get to be so thick that the double plunger pump has trouble pumping the material to the reed beds. Secondary effluent is used to dilute and break up the sludge so it can flow evenly onto and through the reed beds. In May 1985 The Beverly Sewerage Authority, under contract with [RBS], converted 13,400 sq.ft. of open air sand drying beds into artificial wetlands with the planting of the reeds at a spacing of one plant per sq. ft. In the first year (May through December,1985) 50,000 gals of sludge was loaded to the beds. In the spring of 1986 reed plants were popping out all over and sludge was loaded sparingly for the first few months. During the summer months we loaded the bed every 15 days and during the winter we loaded every 30 days. By the end of the year (1986) a total of 208,100 gals of sludge was loaded onto the beds. In addition, 30 cubic yards of stock piled sludge was dumped into the beds with the approval of Reed Bed Systems, Inc.. We also used one portion of a bed for dumping our Jet-Vac sewer cleaning machine which accumulates a great deal of grit and grease from the collection system. In June, 1987 two feet of tongue & groove pressure treated lumber was added to the existing concrete walls, making the total freeboard 4.5 ft high, increasing the life of the beds from 5 years to 10 years.
In December,1993, after eight years of operations, the reed beds were taken out of service because the wooden tongue & groove freeboard retainer walls were popping at the seams, leaking, and bowing out during loading. When the beds were shut down we had approximately 8" of freeboard remaining, and by the time the excavation started in July, 1994 we had almost 12" of freeboard and the sludge had shrunk back off the side walls by five inches. In June, 1994 the Authority bidded out and awarded a contract to excavate and transport the dried sludge to a approved landfill, with the initial understanding that all excavation work would be done from outside of the beds to protect the under drains from damage. Waste Management of PA sampled and tested the sludge for approved land disposal, then made arrangements with the Authority for its ultimate disposal at G.R.O.W.S Landfill , Falls Township, PA c/o Waste Management of PA. In July 1994 the excavation started. The contractor provided an excavator with 30" wide floatation tracks, and due to the fact the reed stems were not harvested that year, the reed stems were layered down by the excavator creating a natural matting under the tracks of the excavator. Therefore we allowed the contractor to enter onto the beds, and within 10 days the entire project was completed. A total of 440.83 Tons of dry sludge was removed. Our costs were:
At the completion of the removal project the under drains of the beds were closed and the beds were flooded with effluent, and within two weeks the reeds started to grow back. A small amount of sludge was applied for the winter. In the spring of 1995 sludge was again applied very lightly -- because of a delay at the DEP office our permit for the reuse of the beds was not received until late spring of 1996.
The loading in 1998 is light because it is the Authority's intention in the
98/99 Capital Improvements Budget to remove all the old wood and concrete walls
and construct all-new, reinforced watertight concrete walls 5’ high, with all new
distribution piping around all the Reed Beds.
In closing I would like to say that the Reed Bed System has worked very well for Beverly, with very little trouble and extremely low maintenance. The reeds have saved Beverly Sewerage Authority a good sum of money over the first eight years of operation. During the period in which we hauled out liquid sludge we paid an average of $37,000 per year in Hauling & Disposal costs. The many visitors that have toured our plant are always surprised how little was involved in implementing and operating such a system and can not believe that they are standing next to millions of gallons of sludge. C. Fredrick Weller, Executive Director |
