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Modulusretro

Index

The table of Loadings detailed oppositewas prepared by the British WaterPackage Sewage Treatment PlantFocus Group comprising all majormanufacturers, suppliers and servicecompanies of all types of small wastewater treatment systems.

The Environment Agency, the NorthernIreland Environment Agency and theScottish Environment ProtectionAgency support the use of this code ofpractice.

This table of loadings allows the totaldaily sewage load from properties to becalculated and it is recommended thatall manufacturers and designers shoulduse this table when sizing and designingnon-mains sewage treatment systems.

The flows and loads values givenrepresent current best knowledgewithin the UK but may change with timein line with per capita water use.

The user/purchaser should be madeaware that there is a risk of poorperformance from the equipment if loadsare understated. The accuracy of thedeclared loads is of paramountimportance. expected total load and theflow, considering both peak and totalflow.

Guidance is provided to assist the userto identify the various sources ofsewage, to consider the nature of thesewage to be treated and to make usersaware of issues which may affect treatability and system performance.

The table of loadings may be used todesign all sizes of sewage treatmentsystems serving up to 1000 population.

FLOW BOD Ammonia as N(Litres) (Grams) (grams)

Domestic DwellingsStandard residential 180 60 8Mobile home type caravans with full services 180 75 8

IndustrialOffice / Factory without canteen 50 25 5Office / Factory with canteen 100 38 5Open industrial site, e.g. construction, quarry, without canteen 60 25 5*Full-time Day Staff 90 38 5*Part-time Staff (4 hr shift) 45 25 3

SchoolsNon-residential with canteen cooking on site 90 38 5Non-residential without a canteen 50 25 5Boarding school (i) residents 200 75 10(ii) day staff (inc. mid-day meal) 90 38 5

Hotels, Public Houses & Social ClubsHotel Guests (Prestige hotels) 300 105 12Hotel Guests (3H & 4H hotels) 250 94 10Guests (Bedroom only – no meals) 80 50 6Residential Training/Conference Guest (inclusive all meals) 350 150 15Non residential Conference Guest 60 25 2.5Drinkers 12 15 5Holiday camp chalet resident 227 94 10Resident Staff 180 75 10Restaurants - Full Meals - luxury catering 30 38 4- pre-prepared catering 25 30 2.5- Snack Bars & bar meals 15 19 2.5- Function Rooms including buffets 15 19 2.5- Fast Food i.e. (roadside restaurants) 12 12 2.5- Fast Food Meal (burger chain and similar) 12 15 4Students (Accommodation only) 100 56 5

Amenity SitesToilet Blocks (per use) 10 12 2.5Toilet (WC) (per use) 10 12 2.5Toilet (Urinal) (per use) 5 12 2.5Toilet Blocks in long stay car parks/lorry parks (per use) 10 19 4Shower (per use) 40 19 2Golf Club 20 19 5Local community sports club, e.g. squash, rugby & football 40 25 6Swimming ( A separate pool without an associated sports centre) 10 12 2.5Health Club/Sports Centre 50 19 4Tent sites 75 44 8Caravan Sites :i) Touring not serviced 100 44 8(ii) Static not serviced 100 44 8(iii) Static fully serviced 180 75 8

Hospitals & Residential Care Homes

Residential old people / nursing 350 110 13Small hospitals 450 140 AssessLarge hospitals Assess individually

*Staff figures also apply to other applications

Flows & LoadsPer person / activity / day (unless otherwise specified)

rangespecification

RETROModel

PopulationEquivalent

MinimumSeptic Tank

volume required

HydraulicFlow

Litres per day

BODLoading

Grams perday

OverallHeight

H

Width

W

Length

L

InletInvert

OR1 6 2700 1080 360 1535 1260 2770 500

OR2 12 4500 2160 720 1920 1260 2770 500

OR3 20 6000 3600 1200 2135 1260 2770 500

Please Note : Larger Retro Systems can be designed and supplied on request.

*Hydraulic flows and BOD loading are based upon British Waters “Flows & Loads” criteria for domestic applications detailed on previous page. All systems must havea fully functional septic tank upstream with an unrestricetd influent from the tank. This is imperative in the performance of this system.

All dimensions in millimetres unless otherwise stated. Oaklands reserve the right to change specification without prior notice in line with our policy of continuous development

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OR1 plant shown below

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