On-Site Wastewater Treatment and Disposal Systems - Forced ...

More documents

Recommendations

Info

‘SU !PJpJapun paaeJo4Jad JO aukoF uado 03~~ pazQa[LoD aq UN 7.uanL44a leq~ OS apeJ6 qq6i 1s e 03 pado 1s KL lensn SC 31 l LAOS palDedwo3 LeJnleu aq~ 40 7sksuo3 rCew Inq ’ AJuosew Jay10 JO alaJ3uo3 pacrnod 40 paq3nJJsuo3 ua240 s4 Ja2 t44 w 40 JOO 14 au l Jke aqa 03 rCLa3aJLp pasodxa 4 b paqe Lnsuk aq l a3e4Jns pues pua JaA03 paaeLnsu& aqa uaaM2aq paMo[le aq p pow (~3 19 03 OE) l u! PZ 02 ZI 40 amis v l pa>e lnsu .L aq p Lnoqs S JaA03 ‘aqea3bp suoia ;puo:, JayaeaM aJaqM l sa3e4Jns Jaq Li4 23aJoJd 03 aAJas 0s Le Kew saweJ4 uapooM uo palunow yqol3 aJenpJey JO suaaJ3s l Le.LJaaew a LqeqCns Jay20 JO ‘ Leaaw paz 1ueA Le6 ‘syue id UapooM paaeaY(a 40 pa33nJlsuo3 aq Kew sJaAo=) l suo~~~puo3 ~0~0 a3npaJ 01 saAJas 0sLe JaA03 ayl l slewkuu ~0 spaaM 40 Juawq3eoJ3ua p!oAe 03 pue ‘suok3cpuo3 Jaqr&eaM aJaAas qsube6e $3a$OJd 03 paJaAo3 aq rCew sJa2 Lc4 ssa33e aaJ j l a3eds paJaAo3 aya U)L(J~M yIq ‘aDe4Jns Jaq L k4 aq$ ahoqe ad id 2uaA leD!JJaA e ql .IM paJuaA aq p Lnoqs au; 1 u )eJp y3ea 40 pua wPaJJsdn ayl l a6JeyDsLp 01 apeJ6 %I 01 cj.0 KLaaewbxoJdde ae pado 1s pue sJa>uaD (w-9-E) 34-11 3e paDeds LLleuuou aJe sauk L u!eJa l ~ooL4 JaalL4 aya U~Y~~M q3uaJq MoLleqs e ukqtjb~ pbe~ aq Kew auki uieJp a43 ‘sJaJL.L4 MOLLPL(S UI *auk L u!eJp aya 0% quanL44a paJa1 ii4 KJJe3 02 pwwd Qvi6k ts aq wow YWM ‘JOOL4 Jai LiJ aqa UO ALl3aJip piei aq rCew sau k L uLeJpJapun ayl l uogaDa ~~03 pue uo~~nq~J~s bp ~04 paLo Ld -wa aq OS Le rCew adkd paleJo4Jad leuobauaAuo3 l qJede (~13 ~‘1) l ur z/l ueyf& JaaeaJ6 JO (~13 9.0) l ub p/l ueql ssal qou paDeds aJe s~.u;o~ $eyl 0s p!et LLLeuuou sk all1 ayl ‘(~13 01) l uc p 40 Jaaaweip wnw~u~w e qqbM LebJaqPw a LqeqdaDDe UP 40 pa$DnJqsuoD aq p Lnoys saui 1 u!eJpJapun aql l e ipaw JaY+LkJ ayl Q~M 6UkDe4JaVJi LaAeJ6 ead payseM 40 (~3 $3) l ur c 40 wnwp~~w e YqhM UkeLJaAO aq ifPW aUOaS JO LaAe.46 aql l (W3 8’s 02 9.0) ‘Ug Z/l-T 02 p/l WOJ4 6uk6ueJ sazbs QCM auoas JO laAeJ6 papeJ6 payseM 40 (a’3 Sz) l uk 01 40 wnw~u~w e aq pLnoys SaLIlL UieJpJapun ~04 LeiJaqew 6ukppaq ayl l a3e4Jns eipaw aya 40 uoi$Jod e aAowaJ ~0 ayeJ 01 aw!a sh 1~ uaqM ‘JaAaMoq fsakaln3!44ip a3ueuaaukew aJeaJ3 LL~M a3bzQeJd s lql l uoisoJa aDe4Jns pboAe 03 parCoLdwa aq os Le AeW e kpaw JaJ ~14 aq$ Jaho pa3e Ld LaAeJ6 ead payseM 40 Jade 1 v l Jno3s a3npa.i LLkM saJeLd ayq 40 KJaydkJad aya punoJe paDe Id sauoqs a6JeL JO saqe Ld yse Lds ay$ punoJe sqJn3 40 asn ayl l a3e4Jns pues aq2 apoJa $0~ op a3e4Jns JaaLl4 aqa 02 rC[lDaJip 6u~6JeqX~p Saul\ leql aJnsu1 02 uale? aq lsnw aJe3 l SJO~nq~J~S ip ifeJds JO ‘Ja$li4 ay3 40 SJaUJO3 JO Jaqua3 ayl le paae3o 1 saqe id yse Ids 03 6u k6JeyDs tp saui ladkd ‘aze4 -Jns aqz& uo pbe[ sq6noJl 40 sueaw rCq aq Lew JaJLb4 aqa 03 uokqnqiJqs!a
.L ‘uo~~ne3 4~4~ Inq ‘paLo tdwa aq rCew s LakJaarru Jayqo ~0 ‘ Leo3 ‘Bets ‘pues 40 saJnax!w ‘sJaaLi4 pa!Jnq JO4 ~LSnO~AaJd pale3lpU4 Sy l Ja32ew 3kue6Jo 40 aaJ4 LeLJalew Je LnueJ6 a LqeJnp ‘paqseM he aq Lew sJa2 lb4 ssame aaJ4 ur parCo Ldwa erpaw Jaa 1 ij ‘$3 JaqdPy3 u& paqbJ3sap aJe ‘SJaJlb4 asay ~04 SWa>Sk uoqdks JO ‘sdwnd pur JaqureyD 6u4sop aql 40 saJnlea4 uokqmJasuo3 pue u6ksap aql SJaqLij 6u~~e[n3J~3a~ E*L*&*g -8-g aJn6i j uk paquasaJd sl yue’) uo~~eln3J~3aJ e 40 3bqewaq3s v l (ahoqe &*g*&*g uob3sas) JaaLi4 ssa33e aaJ4 ay3 ~04 asoya 03 Le3kauapl aJe uoi33nJqs -uo3 Ja2 144 40 s~uatua La ayl l a3e4Jns JaJ Lb4 aqa 07 ssa33e aaJ4 qa!h pa~mJ~suo3 ~~~euuou aJe sJa$Ll4 6ui$e Ln3Ji3aa *L-g aJn6ij uk paauas -aJd si ~3% 1.14 pues T$uar+~~wJa~u~ Buiqe LnWb3aJ LeDidrCq e 40 alk40Jd v •SUO~~&NJO~ 3LqeuIi 13 Aq paJinbaJ se paqe insub pue pap!AOJd aq ptnoqs SJtaAOD l SaALt?A [8JlUO3 put? ‘SJaWkq ‘sdwnd 40 ameuaJu!ew ~04 aLq!ssaD -38 aq yinw ~UQ ay1 l (MoLJ Ja%eMaqsen MeJ 40 awn Lob s ,hp au0 lsea 1 ae 0~ ~ua~e~~rtba wn LOA e JO) yule3 Dkldas ay2 40 azks aql z/l 01 B/T &Le~ou ~4 71 l AU- 2iadas aqa 03 LejJa?ew pue qJ6uaJas lua[ehLnba 40 si yueq UO~~&?[nDJ~3aJ ayl l a3e4Jns Ja3~44 aya 01 aJnax!w JaJeMaJseM aqa sdwnd ‘ ws jueym~ 1% ~3 at+? e Aq pa 1 LoJauoD ‘dwnd v *van L44a Ja2 1 .LJ pUeS 40 uobaJod P SIC LlaM SP ‘yUe2 Di?das e WOJ4 MOL4JaAO aq3 SaAia3 -aJ lueq uogte Ln3JlmJ aq1 l quan 144a Jai ii4 a LSDaJ 03 dwnd e saleJ -odJomi q3bq~ (~aqrrey3 6ucsop) Jaqwey3 uo~~eln3.4~3aJ aya sk Jaqtk4 ssa3 -39 aaJ4 ayq pur ~a3 ~14 6uiae LnDJCDaJ aq2 uaaM3aq amaJa44 .Lp 3kseq aql SaeJOdJO3U 1 ,,aAteA 3w4,, au ‘(6-g aJn6kj) 3uawaBueJJe ,,ariLeA aeoL4,, anbkun e pue ‘WA [PA y3ay3 ‘ saae6 a Lqeahow ‘ saxoq Jaal .L Lds apn LX.J =--ii .spoyaaw 40 &a~Jeh e Kq pa LLoJauos aq rCew soi?eJ uokJetn3Ji3ad ‘(92) 1:s 01 1:~ uaartJaq paysklqeasa rC~~muJou aJe sok$eJ uo~~eln3J~3a~ l sasiJ LaAa 1 JaJrM aql uayM aaa paqJaAuk aya 440 as013 pue dn JeoL4 LL~M t teq au l 3aqseq aJ!rn e ui papuadsns 1 Leq JaqqnJ e pue aal. a Ldwis e ‘8 Jaadeyg ui pun04 aq /few suolge3!4 iDads LoY(3uo3 pue dwnd uo slielaa ‘apCJJaA0 Ja3PM q6bq pue 440-$nqs JeOLJ e lQ!M padd!nba aq plnoys pue c (92) uy~ O& KJaha ukw 01 03 s uaaM$aq aaeJado 01 ~30~3 awb$ e Kq patloJJuo3 aq p[noqs dwnd uok3etn3JiDaJ aql ‘U NJ o< J;;i;: ssaL UC duel uoble Ln3Jb3aJ aql Aadwa 07 paz;s aq p Lnoys Kay1 -asJoy E/I ~04 paaeJ sdumd alqbsJatuqns /CL LeuLlou aJe sdwnd uobqejnDJ LDau
Page 2 and 3:
DE SIGN MANUAL WASTEWATER TREATMENT
Page 4 and 5:
FOREWORD Rural and suburban communi
Page 6 and 7:
Chapter CONTENTS Page FOREWORD ACKN
Page 8 and 9:
Number FIGURES Wastewater Managemen
Page 10 and 11:
FIGURES Number Page ne Saturator Sa
Page 12 and 13:
FIGURES Number Page Use of Metal Ho
Page 14 and 15:
Number TABLES Selection of Disposal
Page 16 and 17:
Number TABLES (continued) Operati o
Page 18 and 19:
TABLES (continued) Number Page of D
Page 20 and 21:
In many areas, onsite systems have
Page 22 and 23:
2.1 Introduction CHAPTER 2 STRATEGY
Page 24 and 25:
subsurface soil absorption is the p
Page 26 and 27:
features of the site (See 3.3.1 and
Page 28 and 29:
2.2.2 System Selection With the pot
Page 30 and 31:
2.2.4 Onsite System Management Past
Page 32 and 33:
determined largely by the physical
Page 34 and 35:
16 - I ,
Page 36 and 37:
Step Client Contact Preliminary Eva
Page 38 and 39:
FIGURE 3-2 EXAMPLE OF A PORTION OF
Page 40 and 41:
Property USDA Texture Flooding Dept
Page 42 and 43:
TABLE 3-3 SOIL SURVEY REPORT INFORM
Page 44 and 45:
found for a subsurface soil absorpt
Page 46 and 47:
Instrument Supported - Abney Level:
Page 48 and 49:
FIGURE 3-8 PREPARATION OF SOIL SAMP
Page 50 and 51:
Sandy Loam + _. ,i . L Silt Loam Cl
Page 52 and 53:
Depth (Ft.) 0 2 4 6 8 10 12 14 Text
Page 54 and 55:
Grade Structureless Weak Moderate S
Page 56 and 57:
Excavated Soil Material (Tamped in
Page 58 and 59:
If test results agree with this tab
Page 61 and 62:
Percolation test FIGURE 3-15 PERCOL
Page 63 and 64:
mm..--- - --- FIGURE 3-16 COMPILATI
Page 65 and 66:
FIGURE 3-16 (continued) 0 Texture S
Page 67 and 68:
13. Winneberger, J. T. Correlation
Page 69 and 70:
is the overall socioeconomic status
Page 71 and 72:
FIGURE 4-l FREQUENCY DISTRIBUTION F
Page 73 and 74:
extreme, however, minimum and maxim
Page 75 and 76:
4i2.2.2 Individual Activity Contrib
Page 77 and 78:
and the resultant wastewater charac
Page 79 and 80:
TABLE 4-7 TYPICAL WASTEWATER FLOWS
Page 81 and 82:
TABLE 4-9 FIXTURE-UNITS PER FIXTURE
Page 83 and 84:
4.3.2 Wastewater Quality The qualit
Page 85 and 86:
* FIGURE 4-3 STRATEGY FOR PREDICTIN
Page 87 and 88:
12. Witt, M. Water Use in Rural Hom
Page 89 and 90:
5.2 Water Conservation and Wastewat
Page 91 and 92:
5.2.2 Water-Saving Devices, Fixture
Page 93 and 94:
TABLE 5-2 (continued) Total Flo Red
Page 95 and 96:
Generic Typea Description Pit Privy
Page 97 and 98:
TABLE 5-4 WASTEWATER FLOW REDUCTION
Page 99 and 100: 5.2.2.3 Clotheswashing Devices and
Page 101 and 102: Generic Typea Description Mixing Va
Page 103 and 104: TABLE 5-6 WASTEWATER FLOW REDUCTION
Page 105 and 106: TABLE 5-7 EXAMPLE POLLUTANT MASS RE
Page 107 and 108: FIGURE 5-l EXAMPLE STRATEGIES FOR M
Page 109 and 110: In most situations, projections of
Page 111 and 112: FIGURE 5-3 FLOW REDUCTION EFFECTS O
Page 113 and 114: 5.7 References 1. 2. 3. 4. 5. 6. 7.
Page 115 and 116: 6.1 Introduction CHAPTER 6 ONSITE T
Page 117 and 118: l SauJUOdtUo3 lesodsip pue JuJmeJJa
Page 119 and 120: l ALJadoJd aeo 14 JO a[aaas aou Kel
Page 122 and 123: ‘($3) %gg 40 uo~a3npaJ e (3as/w t
Page 124 and 125: l salpnqs asaq 49 s3 LnsaJ ayq saz!
Page 126 and 127: hei!ues I I i I 1 I PCm I b j- I. -
Page 128 and 129: : apn L3u k suo!qeJap csuo3 Jaq30
Page 130 and 131: *an LeA a Lqeuoha -sanb 40 JJe pue
Page 132 and 133: (01) NOIlV3IlddV MO7 39tiVl llOzi 1
Page 134 and 135: l suo~~~puo3 Le~uawuoJ~Aua JaaLk4 p
Page 136 and 137: l 3n aqq Kq pazkJa23eJeq3 sh q3LqM
Page 138: .aJn7eJal k L aqq u k pays k Lqeasa
Page 141 and 142: 9-9 37flVl pSil3111~ lN311IbWl1NI 3
Page 143 and 144: l paq aqq 40 aDe4Jns aACleJaLi4u .L
Page 145 and 146: ‘8 Jaad&?ys ul pun04 aJle suoyd!s
Page 148 and 149: l Ja$lk4 ay3 ukqq!M JaaewaaseM 40 u
Page 152 and 153: P- &JLXLJ~e~Jl~Jd UJOJj C . - A 1a~
Page 154 and 155: a3ueua2ukew pue uobJeJad0 8.E.g LeJ
Page 156 and 157: sameualJnddv axanbas Jau il SLOJ7.t
Page 158 and 159: eJJaakJ3 u6isaa Z’6’E’g *asop
Page 160 and 161: 318QaQEi33aNON 01-9 3msu simaotld N
Page 162 and 163: SNOIlQ~tl9I~N03 1NQld 39QI3Qd NOIlQ
Page 164 and 165: El-9 31av1 S3ItX-US 01313 1INt-l 31
Page 166 and 167: d. Method of Aeration Oxygen is tra
Page 168 and 169: contain electrical components, they
Page 170 and 171: control that results in power savin
Page 172 and 173: TABLE 6-16 OPERATIONAL PROBLEMS--EX
Page 174 and 175: I TRICKLING FILTFR FIGURE 6-12 EXAM
Page 176 and 177: presents suggested design ranges fo
Page 178 and 179: Item Media Tank Aeration System RBC
Page 180 and 181: Observation Filter Ponding Filter F
Page 182 and 183: TABLE.6-21 HALOGEN PROPERTIES (27)
Page 184 and 185: The use of chlorine as a disinfecta
Page 186 and 187: HOC1 , would predominate. It is cle
Page 188 and 189: 6.5.2.5 Construction Features a. Fe
Page 190 and 191: e Wastewater FIGURE 6-14 IODINE SAT
Page 192 and 193: (experience with some units indicat
Page 194 and 195: directing flow through and around t
Page 196 and 197: FIGURE 6-17 TYPICAL UV STERILIZING
Page 198 and 199: Shigella TABLE 6-25 UV DOSAGE FOR S
Page 200 and 201:
Cleaning of quartz glass enclosures
Page 202 and 203:
the bubble diffuser units to lo-30
Page 204 and 205:
TABLE 6-26 POTENTIAL ONSITE NITROGE
Page 206 and 207:
Nitrification of septic tank efflue
Page 208 and 209:
Influe? Effluent 0 Tank Denitrifica
Page 210 and 211:
solution. It can be used to remove
Page 212 and 213:
TABLE 6-27 POTENTIAL ONSITE PHOSPHO
Page 214 and 215:
Anionic polyelectrolytes can be use
Page 216 and 217:
component of the onsite treatment s
Page 218 and 219:
7. 8. 9. 10. 11. 12. 13. 14. 15. 16
Page 220 and 221:
30. 31. 32. 33. 34. 35. 36. 37. 38.
Page 222 and 223:
58. 59. 60. 61. 62. 63. 64. 65. 66.
Page 224 and 225:
7.1 Introduction CHAPTER 7 DISPOSAL
Page 226 and 227:
7.2.1.2 System Selection The type o
Page 228 and 229:
Distribution FIGURE 7-2 TYPICAL BED
Page 230 and 231:
TABLE 7-l SITE CRITERIA FOR TRENCH
Page 232 and 233:
TABLE 7-2 RECOMMENDED RATES OF WAST
Page 234 and 235:
can slough off the sidewall. These
Page 236 and 237:
FIGURE 7-3 ALTERNATING TRENCH SYSTE
Page 238 and 239:
FIGURE 7-4 PROVISION OF A RESERVE A
Page 240 and 241:
FIGURE 7-5 TRENCH SYSTEM INSTALLED
Page 242 and 243:
TABLE 7-4 DOSING FREQUENCIES FOR VA
Page 244 and 245:
The depth of the porous media may v
Page 246 and 247:
Distr Pipe, FIGURE 7-6 TYPICAL INSP
Page 248 and 249:
against freezing and to stabilize .
Page 250 and 251:
Pertodic Deternvne Cause u O&loadin
Page 252 and 253:
oils, and greases, can cause failur
Page 254 and 255:
4" Inspection Pip FIGURE 7-9 SEEPAG
Page 256 and 257:
The same guidelines used in locatin
Page 258 and 259:
Straw, Hay or Fabric? FIGURE 7-10 T
Page 260 and 261:
I tern Landscape Position Slope Typ
Page 262 and 263:
The acceptable depth to an impermea
Page 264 and 265:
FIGURE 7-12 PROPER ORIENTATION OF A
Page 266 and 267:
Mound Height TABLE 7-9 DIMENSIONS F
Page 268 and 269:
Example 7.1: Calculation of Mound D
Page 270 and 271:
1.0 + 1.4 = - t 0.75 + 1.5 1 [ = (3
Page 272 and 273:
. Fill Placement Step 1: Place the
Page 274 and 275:
7.2.4.6 Considerations for Multi-Ho
Page 276 and 277:
7.2.5.2 Application a. Site Conside
Page 278 and 279:
7.2.6 Artificially Drained Systems
Page 280 and 281:
---- FIGURE 7-17 UNDERDRAINS USED T
Page 282 and 283:
periods, particularly on level site
Page 284 and 285:
TABLE 7-11 DRAINAGE METHODS FOR VAR
Page 286 and 287:
high water table elevation. To prev
Page 288 and 289:
FIGURE 7-18 TYPICAL ELECTRO-OSMOSIS
Page 290 and 291:
7.2.8.1 Design a. Single Line . Sin
Page 292 and 293:
Inlet From Pretreatment or Previous
Page 294 and 295:
watertight Pipe & Joints1 FIGURE 7-
Page 296 and 297:
ox networks (see Figure 7-23). Howe
Page 298 and 299:
280 s P 4
Page 300 and 301:
FIGURE 7-26 LATERAL DETAIL - TEE TO
Page 302 and 303:
To simplify the design of small pre
Page 304 and 305:
FIGURE 7-29 RECOMMENDED MANIFOLD DI
Page 306 and 307:
Step 3: Select lateral diameter. Fo
Page 308 and 309:
Step 8: Select proper pump or sipho
Page 310 and 311:
Friction loss in 25 ft 2. Velocity
Page 312 and 313:
FIGURE 7-32 DISTRIBUTION NETWORK FO
Page 314 and 315:
In summary, the final network desig
Page 316 and 317:
7.2.8.3 Construction FIGURE 7-33 SC
Page 318 and 319:
Since the network is pressurized, s
Page 320 and 321:
FIGURE 7-35 CROSS SECTION OF TYPICA
Page 322 and 323:
The capillary rise characteristic o
Page 324 and 325:
The hydraulic loading rate is deter
Page 326 and 327:
during the critical months of the y
Page 328 and 329:
7.3.3 Evaporation and Evaporation/I
Page 330 and 331:
FIGURE 7-37 TYPICAL EVAPORATION/INF
Page 332 and 333:
October November December January F
Page 334 and 335:
7.3.3.7 Seasonal, Multifamily, and
Page 336 and 337:
13. 14. 15. 16. 17. 18. 19. 20. 21.
Page 338 and 339:
38. 39. 40. 41. 42. 43. 44. 45. 46.
Page 340 and 341:
The grease traps discussed here are
Page 342 and 343:
Type of Fixture Restaurant kitchen
Page 344 and 345:
Removable Slab Inlet --CL Tee with
Page 346 and 347:
- 8.3.3 Factors Affecting Performan
Page 348 and 349:
The pumping head is calculated by a
Page 350 and 351:
liquid level drops, the weights los
Page 352 and 353:
8.3.5 Construction The tank must be
Page 354 and 355:
Hori FIGURE 8-6 TOP VIEW OF DIVERSI
Page 356 and 357:
9.1 Introduction CHAPTER 9 RESIDUAL
Page 358 and 359:
Parameter TABLE 9-2 CHARACTERISTICS
Page 360 and 361:
Parameter Total Coliform Fecal Coli
Page 362 and 363:
9.4.1 Land Disposal Four methods ca
Page 364 and 365:
TABLE 9-4 (continued) Alternative D
Page 366 and 367:
W z Process Lagooning (1)(13)(14) (
Page 368 and 369:
Process Description Liouid Stream S
Page 370 and 371:
11. 12. 13. 14. 15. 16. 17. 18. 19.
Page 372 and 373:
Some of the techniques discussed ma
Page 374 and 375:
10.3.1 State Agencies Except for th
Page 376 and 377:
10.3.4.1 Private Nonprofit Institut
Page 378 and 379:
10.4.1.1 Standards for Site Suitabi
Page 380 and 381:
Scope of Activities Perform inspect
Page 382 and 383:
Scope of Activities Perform necessa
Page 384 and 385:
10.4.4.1 Inspections Inspections co
Page 386 and 387:
SYSTEM 1. U.S. Bureau of Reclam$t~o
Page 388 and 389:
FIGURE A-2 TEXTURAL TRIANGLE DEFINI
Page 390 and 391:
Class Platelike. with one dimension
Page 392 and 393:
saturation may be necessary to conf
Page 394 and 395:
the porosity of soils containing mo
Page 396 and 397:
FIGURE A-5 SOIL MOISTURE RETENTION
Page 398 and 399:
A.3.3 Flow of Water Through Layered
Page 400 and 401:
GLOSSARY A horizon: The horizon for
Page 402 and 403:
following chemical flocculation; wi
Page 404 and 405:
floodway: A channel built to carry
Page 406 and 407:
ped: A unit of soil structure such
Page 408 and 409:
solids: Material in the solid state
Page 410 and 411:
TECHNICAL REPORT DATA (Please read
show all

On-Site Wastewater Treatment and Disposal Systems - Forced ...

Create successful ePaper yourself

Delete template?

Save as template?