The low down on sep­tic tanks

Matamata Chronicle - - Building -

THERE are spe­cific rules gov­ern­ing sep­tic tank in­stal­la­tion and sit­ing. 1. Mod­ern pre-treat­ment sys­tems

– A pre-treat­ment sys­tem is the first stage in han­dling house­hold waste flows be­fore dis­charge to land. Mod­ern non-flush toi­let sys­tems for dwellings with­out wa­ter clos­ets in­clude:

VIP toi­lets (or ven­ti­lated im­proved pit toi­lets) Com­post­ing toi­lets De­hy­drat­ing toi­lets Non-flush toi­let sys­tems re­quire a grey wa­ter sep­tic tank and soak sys­tem to han­dle kitchen, bath­room and laun­dry waste wa­ter.

2. Mod­ern pre-treat­ment sys­tems for full wa­ter­borne waste­water ser­vic­ing (flush toi­let black­wa­ter plus kitchen, bath­room and laun­dry flows) in­clude:

Aer­o­bic treat­ment plants (aer­ated sys­tems and biofil­ter sys­tems)

Ad­vanced sep­tic tank and sand fil­ter (or fab­ric fil­ter)

Ad­vanced sep­tic tanks (larger tanks with spe­cial ef­flu­ent out­let fil­ters in place of an out­let tee)

3. Mod­ern lan­dap­pli­ca­tion sys­tems

– A range of soil treat­ment sys­tems is now avail­able where trench sys­tems are not suit­able. These in­clude: Dripline ir­ri­ga­tion ETS beds (evap­o­tran­spi­ra­tion-seep­age)

LPED trenches (low­pres­sure-ef­flu­ent­dis­tri­bu­tion)

Wis­con­sin Mounds for boggy ar­eas or thin soils over rock or high ground­wa­ter.

ETS, LPED and mounds use the soil to treat ad­vanced sep­tic tank ef­flu­ent in a far more ef­fec­tive way than tra­di­tional sep­tic tank and trench sys­tems.

Dripline sys­tems dis­perse high qual­ity treated waste­water into gar­dens where ad­van­tage can be taken of the ef­flu­ent’s nu­tri­ent and wa­ter value. Usu­ally the most en­vi­ron­men­tally ef­fec­tive on-site waste­water sys­tem com­prises ei­ther an aer­o­bic treat­ment plant or a sand fil­ter plant, both of which pro­duce high qual­ity ef­flu­ent for sup­port­ing plants in land­scaped ar­eas through dripline ir­ri­ga­tion.

Sep­tic tanks re­quire am­ple top­soil and or­ganic mat­ter to en­able bac­te­ria to break down sep­tic tank ef­flu­ent and al­low the wa­ter in the ef­flu­ent to soak away ef­fec­tively.

The soil pro­vides the ma­jor­ity of the treat­ment in a sep­tic tank and soak trench sys­tem.

Poor soils re­sult in sys­tem fail­ure.

The treat­ment process in an aer­o­bic plant or sand fil­ter sys­tem breaks down most of the waste mat­ter and cre­ates nu­tri­ents for plant growth.

The soil is the least im­por­tant part of the treat­ment process but cap­tures bac­te­ria and viruses to al­low them to die off with time. En­gage a De­signer – A de­signer will ar­range an in­ves­ti­ga­tion of your site, its soil con­di­tions and nat­u­ral drainage pat­terns, and then dis­cuss where you would like to put your dwelling and other on-site fa­cil­i­ties.

Check with your coun­cil re­gard­ing de­sign­ers op­er­at­ing in your area.

Ap­ply­ing for a build­ing per­mit for your on-site sys­tem

– Your de­signer will also find out what your district coun­cil’s re­quire­ments are and check if your re­gional coun­cil has set any spe­cial en­vi­ron­men­tal re­quire­ments for on-site sys­tems in your area.

Us­ing an al­ter­na­tive tech­nol­ogy sys­tem

– If you de­cide to go with one of the al­ter­na­tive tech­nol­ogy sys­tems check with your de­signer as to its suitabil­ity for your site.

Make sure you ask about the sys­tem’s per­for­mance record and, if ap­pro­pri­ate, ask the sup­plier or in­staller for a per­for­mance guar­an­tee over the first three years of use.

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