WorldWide Drilling Resource

34 OCTOBER 2016 WorldWide Drilling Resource ® HDD Goes the Distance for Wastewater in Maryland Compiled by Editorial Staff of WorldWide Drilling Resource ® Anne Arunde County, Mary and, s overhau ng approx mate y 28,000 near feet of sewer force ma ns. The county s us ng hor zonta d rect ona dr ng (HDD) to protect ex st ng nfrastructure, m n m ze env ronmenta d sturbance, and s mp fy regu atory rev ews and approva s. The commun ty of Mayo, south of h stor c Annapo s, Mary and, s ocated on a pen nsu a between the South R ver and the Rhode R ver, wh ch both run nto northern Chesapeake Bay. Regarded as a state treasure n Mary and, Chesapeake Bay s a favor te dest nat on for recreat ona boaters, and a host to s gn f cant crab and oyster f sher es. The Mayo Water Rec amat on Fac ty (MWRF), owned and operated by Anne Arunde County, pumps sept c tank eff uent from homes and bus nesses on the pen nsu a, treats the waste to meet current requ rements, then d scharges the treated eff uent nto the bay. The Mary and Department of the Env ronment s requ r ng the county to upgrade the eve of treatment for wastewater co ected from the Mayo pen nsu a to ach eve enhanced nutr ent remova (ENR) performance by January 2017, a statew de dead ne. After deta ed ana ys s, the most cost-effect ve means of prov d ng ENR eve treatment for a wastewater or g nat ng on the Mayo pen nsu a was to decomm ss on the MWRF and pump wastewater to a arger treatment fac ty n Annapo s, a so operated by the county and a ready upgraded for ENR performance. Br er ey Assoc ates ass sted w th the project s concept deve opment and des gn. The se ected a ternat ve nvo ved construct on of approx mate y 28,000 feet of new force ma n to transport wastewater from the Mayo area northward to the ex st ngAnnapo s Water Rec amat on Fac ty. Once the new force ma n s n serv ce, the MWRF w be converted nto a reg ona sewer pump ng stat on. Due to the ength of the project, construct on was d v ded nto seven separate contracts. The f rst of these contracts was the 4100-foot a gnment beneath the South R ver. G ven the sens t ve ecosystem, HDD was used to nsta th s f rst sect on. Br er ey Assoc ates ed the HDD des gn team through subsurface ground cond t ons cons st ng of deep, very soft so s. To m t gate the potent a of nadvertent dr f u d osses, a bore depth of over 100 feet be ow r ver bottom was chosen; 24- nch d ameter, DR-7 HDPE capab e of w thstand ng nsta at on forces was a so se ected. Carson Corporat on of Lafayette, New Jersey, began dr ng on October 30, 2015, and the f na pu was comp eted on December 15, 2015. To m n m ze d sturbance to adjacent res dents, HDD w a so be dep oyed to nsta the major ty of the rema n ng sect ons wh ch range from about 1100 feet to 3000 feet n ength. G ven the var ab e subsurface cond t ons, both DR-9 and DR-11 HDPE w be used. HDD operations in Anne Arundel County Maryland. Images courtesy of Brierley Associates. )0&"%1 "6)&4 ,, ,, 2)&0 -%3120*"+ )0&"%1 "-% 312., )0&"%1 "-3'"$230&0 .' -&02*" !&+%&% 0*++ */& 3"+ !"++ 0*++ */& !*0&+*-& 0*++ .% "1*-( .,/.1*2& !*0&+*-& 0*++ .%1 .-*$ 0*++ */& "1*-( *21 &0$311*.- "1*-( *21 0*++ .++"01 *1)*-( ..+1 3#1 2"02&0 .%1 "-% 2"#*+*7&01 + */ -$ 0* + & )*0% 2 8 !*-12&% ).-& 8 8 "5 2., %0*++/*/&*-$ $., 8 444 %0*++/*/&*-$ $.,