Page 22: of Maritime Reporter Magazine (July 2013)

22 Maritime Reporter & Engineering News ? JULY 2013 TECHNICAL FEATURE WASTE WATER DISCHARGE agulants that create metal hydrox-ides, it is felt that additional treat-ment is needed to achieve a level of non-detect in analysis of storm water or industrial efß uent. Com- parison of West Coast passive Þ ltra-tion systems indicates a low range of 25 ? 42% treatment efÞ ciency to a high range of 94.5 ? 98.2%. It was obvious that site conditions and pollutant loads vary from opera-tion to operation and from location to location. The Paci Þ c Northwest Pollution Prevention Resource Center cites more than 100 PaciÞ c Northwest shipyards where pas-sive Þ ltration is used with consis- tent good results in these ranges in their report ?Pollution Prevention at Shipyards.? Thus, with the combi- nation of precipitate processes and passive Þ ltration methods, it was expected that the URS/Marisco 3PF System would have the capacity to achieve complete removal of target constituents, designed to effectively employ coagulation, precipitation, sedimentation and passive Þ ltration to achieve State of Hawaii Depart-ment of Health regulatory levels of 2.9 ?g/L for copper and 95 ?g/L for zinc.To test and evaluate the design, URS and Marisco assembled a table-top unit. Built to scale, this model incorporated all of the components of the intended full-scale model and was constructed at Marisco?s dry dock location to receive waters from the wash down process containing copper and zinc. Marisco discontin-ued implementation of other BMPs during vessel maintenance to create a worst-case scenario as can be seen in the system inß uent levels in the compiled data below. Two testing regimes were conducted, and analy-sis on samples was executed by an accredited laboratory. Results in- MARISCO, LTD. 3PF System Test Phase I Results Sample ID Representing Result pH Result Cu Result Zn Result Cu Result Zn (Std. Units) (Ttl. ?g/L) (Ttl. ?g/L) (Dis. ?g/L) (Dis. ?g/L) DeckWash Resid From Deck A First Deck Wash 7.90 8800 7700 730 990 Deck Wash Resid From Deck B Second Deck Wash 8.26 340 280 22 ND Deck Wash From Tote System In ß uent 8.33 5200 3700 920 580 3PF Treated Wash Resid System Ef ß uent 10.6 140 90 45 80 UndockPunapau Compliance 8.21 ND ND n/a n/a Reduction in Ttl. Cu from deck wash ? 93.5% Reduction in Ttl. Cu from treatment process ? 97.3% Reduction in Ttl. Zn from deck wash ? 92.4% Reduction in Ttl. Zn from treatment process ? 97.6% Reduction in Dis. Cu from deck wash ? 97.6% Reduction in Dis. Cu from treatment process ? 95.1% Reduction in Dis. Zn from deck wash ? 100% Reduction in Dis. Zn from treatment process ? 86.2% MARISCO, LTD. 3PFS Test ? Phase II November 23, 2012 Sample ID Result Result Cu Result Zn Result Cu Result Zn pH (su) (Ttl. ?g/L) (Ttl. ?g/L) (Dis. ?g/L) (Dis. ?g/L)System Inß uent 8.10 1,700 2,100 120 120 System Efß uent (3-hour) 10.9 ND 23 ND ND System Efß uent (24-hour) 12.5 ND ND ND ND MARISCO, LTD. Deck Wash Ef cacy Test ? Phase I Sample ID Result Result Cu Result Zn Result Cu Result Zn pH (su) (Ttl. ?g/L) (Ttl. ?g/L) (Dis. ?g/L) (Dis. ?g/L)First Deck Wash 7.88 28,000 18,000 870 1,000 Second Deck Wash 8.47 1,500 710 74 29 Third Deck Wash 8.38 50 110 ND ND Compliance Ambient 8.07 29 ND NA NA Compliance Efß uent 8.12 ND ND NA NA Please note that Phase I involved only 45 minutes of treatment time while Phase II incorporated both 3- and 24-hour treatments. The deck wash efÞ cacy is merely to illustrate the effec- tiveness of deck washing and includes illustration of incremen- tal reduction in copper and zinc concentrations with an ultimate measurement of non-detect in the compliance efß uent sample. MR #7 (18-25).indd 22MR #7 (18-25).indd 227/1/2013 9:07:20 AM7/1/2013 9:07:20 AM