1402 SE EVERETT MALL WAY MR BILLS 2018-01-01 MF Import

01-04-1993 04�11PM FkOM Aard�ark eny TO 2596856 P.03 _ i�' �� Page ? M�, Bill's, Everett Mall December 15, 1992 The semi-au[omatic grease traps are more straight forwazd. A valve at tLe discharge of the grease trap is closed, causing grease [o be discharged throngh a hose to a container. The problem [hen is that the operator has to be able to judge whether the disr�atge from the hose is grease or water. Tka cleaaing of such s trap w< . oe more ditticult due to che additional gieces of the assemb!•�, The hose and valve would alao hart to be cicaned. In general, all grease traps have to be cleaned out periodically. Some more frequently t6an others. The longer between cleanings, the moze unpleasant tfie task becomes. This is why 1 would not oversize a grtase trap: Oversizing increases the time intervals be[ween cleanings whicL makes the task more unplaasant, which incresses the possibility of the task beiug coaveaieatly 'forgotten". Injection of enzymes or solvents into the grease lines will not replace cleaning a grease trap. It would be unwise to assumc that � bio•agent or solvent would remove all the grcase, all the time. Tberc are too many varinbles to consider. The advaatage of the enzyme ar solveni is co improve the �pr,ration of a grcase removal system and prevent accnmulation of grease ia the sewer. That is why the cities of Bellevue and Renton have adopted the requirement. We fcel the slJition of an enzyme injCction system is only an enLanccment to a properly desigaed greue extractioa system. Enzyme injection should provide the City with uot only a level of confideuce, buc also a means of protecting their sewer ietras[ructure. I coatac[ed two manufacturers' reprasentativ�s to obtain information as to the cmount of grease which could be digested by the enzymes. Thcir responses were that they don't provide that type of �pecification for a number of reasons, Primerily, there ue lots af difCerent types of grease and some are harJer to digesi than uthers. Additionally, the temptrature o( the watcr cnteriag the grease trap greatly affects the yiability of the enzymes: Too hot a water could kill off th� enzymes, colder tcmperatures slow down the digesdoa rate. There are so many vnriables and no standards of such. TLe manufacmrers do not try to prnvide aa alrernative to grcase traps, they just offer a product tha[ malces properly sized tr�pa wwk hctter. . As I mentioned in the meeting, the plumhing design is not yet �omplete due to a lack nf information nbout the kitchea design. Today I received some additional data which is pertiaeat to our discussion. The pot aink will be a three compartmcat, 24x24x12" deep unit, and will be the only equiproent diachnrge ia[o [he greose trap. (The disbwasher will not be connectcJ per direction of the City of Everett Plumbiag InSpectors.) The grease trap has now been re-sized in aecordance with the pamphlet T provided lo you a[ Chc meeting: "ASPE Data Book, Cflapter 35: Grease Interccptors". A low boy type above gronad model Las been selected to fit vnder the sink (max. height �0", including atcess). The following calculalions sbow how the trap is si c�.d: Size of sink: (3) (24x24x12) = 20,735 cubic inches. Assu_ : each sink is 75% full Cor �olume ot pots ttnd pans (.75) 20,73G = 15,552 cabic ;nches. Convert ta gallons = 15,552 + 231 cubic inches/gallon = 67.3 �allons. Using a 2 minu[e drain period yields a 33.65 gpm size