ESTILOS DE APRENDIZAJE Y ESTRATEGIAS ACTIVAS
Phillips 66 (también llamada Discusión 66) es una técnica de
2.3.2.1 T his reg ulat ion req u i res that:
‘W here w ater is sup p li ed by a w ater u nde rtaker or l icen sed w a ter supp l ier and is the n further distr ibute d by a person oth er than a w ater undertaker or l ice nsed w ater su pp li er the monitor in g must be carri ed out o n the basis of the risk a ss essment ’.
2.3.2.2 T hese supp l ies ar e ref erred to as supp li e s f rom private distribution n etw orks in th is g ui dan ce.
2.3.2.3 As part of the risk assessment f or a pri va te distri but ion n et wo rk , the loc al author it y n eeds to li ais e with th e water un dertak er (or the l icen sed water s upp li er) about th e q ual it y of the water del i vered to the b ou ndar y of the premise s. T he wat er shou ld compl y wit h al l the s tandards and ind ic ator parameters at th is poi nt un less th e und ertak er (or suppl ier) , as a cons eq uence o f a past or current f ail ur e, has a prog ramme of work in pl ace to ach ie ve c ompl ia nce. T he undertak er (or supp li er) is req uir ed t o pro vi de the loc al a ut horit y with th is inf ormation, i nc lud ing det ai ls of undertak ing s, authoris ed de partures a nd not ices, whi ch se t out
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what remed ia l act ion /impro veme nt work s ha ve b een ag reed wi th DW I. T his shou ld ide ntif y an y parameters that shou ld be
monitore d at cons umers’ taps wit hi n the p ri vate d istr ibut ion
net work as a con seq uence of the q ualit y of the water su pp li ed by the und ertak er (or supp li er). In most cases no suc h paramete rs wi l l be ide ntif ied.
2.3.2.4 T he purpose of monitoring is to ver if y wh ether the contro l measures in p lac e to ensure the s af ety of drink ing water are eff ective. T hus the a ssessment of potenti al ri sk s and measure s put in p la ce to mit ig ate these r isk s is us ed to inf orm the nee d f or monitor ing on a cas e -by-c ase b as is. T he l oca l author it y ne eds to assess wh ich p arameters cou ld b e in d a ng er of f ailing to meet a standard or in dic ator parameter as a co n seq uence of the natu re (f or example th e p ip es, tank s, materials and l a y out) an d the cond iti on (f or examp le corro si on of iron mains, f req uency of bursts) of the pri vate distri but ion n et work and the nat ure an d cond iti on of the pip e work and f itting s wit hin th e bu il di ng s (f or examp le the pre senc e of lead p ipes, the hyg ien ic co nd itio n of the taps/in serts). If plastic p ipe s f orm part of the pri vate d istrib uti on net wor k or the pi pe work with in prem ises and there are petro l , die se l or oi l storag e f acilit ies wit hi n the p remises, loca l
author itie s sho ul d be a ware that a n y sp i ll ag e of these subst an ces cou ld permeat e the pla stic p ip es an d ca use an of f ensi ve tast e, odour or a ppe aranc e of the water sup pl y. If the undertak er (or supp l ier) has h ad a past prob lem with p o or treatment result in g in depos it ion of iron, m ang anese or al umin i um in the d istri but io n net work , or corrosi o n of iron mains in th e distr ibut ion net work , these de pos its ma y ha ve b een transf erre d into th e pri vate distr ibut ion n et work and risk f ailure s to meet the standar ds for these par ameters at consumers ’ taps.
2.3.2.5 T heref ore some exa mples of parameters that loca l a uthor itie s shou ld co ns ider the need to mon itor in pr i vate d istr ibut ion net work s, depe nd ing on the resu lts of the risk assessment inc lu de the f oll o wing (this l ist i s i ll ustrati ve and is not exhau sti ve) :
• coliforms and E.coli (ingress into the network or poor hygienic cond iti ons, es pec ia ll y tank s);
• colony counts (upward trend may indicate deterioration of water q ual it y) ;
• conductivity, hydrogen ion and turbidity ( as per the notes in Sche du le 1, Part 2, I ndi cator Par ameters) ;
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• iron and zinc (from corrosion of galvanised steel or cast iron pip es). Note th at zin c is not a p arameter in the Reg ul atio ns b ut it can oc cur wh en g a l va nis ed p ipe s are pr esent an d reg ulat ion 4(a) inc lu des a n y su bstance wh ich c onst i tutes potent ia l risk to human he alt h;
• iron, manganese, aluminium and turbidity (deposits from poor past treatment);
• taste and odour (ingress and permeation of plastic pipes); • trihalomethanes and bromate (disinfection by-products)
(espec ia l l y if there is chlor in atio n with in the pri vate distr ibut ion n et work ); and
• lead, nickel and copper (from the pipe work or tap fittings in the pri vate d istrib uti on net work or with in the premis es. 2.3.2.6 If the risk assessme nt sho ws th at monito ring of one or more
parameters i s nec es sar y to determi ne wh ether the stan dards and ind ic ator parameters are met at consume rs’ taps in prem ises supp l ied thro ug h the pri vate d istr ibut ion net work , the loc al
author it y wil l h a ve to deci de on th e f req uenc y of monitori ng . T he f req uenc y wil l de pen d on the deg ree of percei ved r isk of f ailin g to meet the standar d or ind icator p arameter, the lik e l y var iati on i n the conc entrati on or va l ue of the parameter, the results of any pre vi ous mon itor ing , the nature an d e xte nt of the privat e distr ibut ion n et work and the t yp es of premises su pp li ed. If the monitor ing sho ws a fai lure of a standar d or a f ailure of an ind ic ator parameter t hat is a p otent ia l da ng er to human hea lt h due to the pr i vate di stribut ion n et work or the cond iti on of the pip e work with in prem ises , the loca l a uthor ity i s req uired to tak e
appropr iate acti on (s ee sect ion 9( E).2.4 o f this g uida nce). If the monitor ing sho ws th at the conce ntrati on s, va lu es or states o f the parameters are we ll with in th e permitte d le vels and suf f icient monitor ing (enoug h sampl es o ver a p eri o d of time, say t wo ye ars) has be en un dertak en , the loca l a uthor ity may d ec ide th at f urther monitor ing of the privat e di strib utio n net work is not req uire d f or some parameters, b ut it shou ld al wa ys monitor f or microbi ol og ica l parameters. T he lo c al aut horit y s hou ld r evi e w its risk assess ment when e ver ther e is a n y s ig nif icant c hang e in c ircumstan ces an d it must revie w it as a minimum e ver y f ive ye ars.
2.3.2.7 If the risk assessme nt sho ws th at a f eature of the private distr ibut ion n et work i s a potent ia l risk , f or exampl e a ser vice reser vo ir or co ll ecti o n chamber, the loca l authorit y s hou ld c ar ry out monitor ing f or appropri ate paramet ers , f or examp le
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f eature. A series of col on y co unt resu lt s wi l l in di cate wheth er there is a tre nd an d potent ia l deter iorat io n in water q ual it y. 2.3.2.8 In the case of f urther distri buted water b eing sup pl ie d to a pu bl ic
bui ld ing , then the r is k assessment als o n eeds to tak e into cons iderat io n the do mestic d istri buti on s ystem of the pub li c bui ld ing .