KENYA STANDARD                   KS 2 767-11:2020  
                
   
 
 
 
 
 
 
  
 
 
 
 
 
 
 
Wastewater treatment plants  - Part 11: 
General data required  
 
 
 
 
 
 
 
 
 
 
©KEBS 2020                         First  Edition 2020 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 KS 2 767-11: 2020                                                                                                    
        
 
ii                     © KEBS 2020 — All rights reser ved TECHNICAL COMMITEE REPRESENTATION  
 
The following organizations were represented on t he Technical Committee:  
 
1. CSI International ltd  
2. Dousglobal Management solutions  
3. Ecosave Africa Ltd  
4. Embu Water and Sanitation Company LTD  
5. Environment Institute of Kenya  
6. Green Kenya Investment Corporation  
7. Jomo Kenyatta university of agriculture and technology  
8. KenGen PLC  
9. Kenya Chemical Society  
10. Kenya water Institute  
11. Kenyatta  university  
12. Nairobi City Water and Sewerage Company  
13. National Environment Management Authority  
14. National Public Health Laboratory  
15. Synergy  Ltd 
16. Taita Taveta University  
17. TANATHI Water Works Develop ment Agency  
18. Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
 
 
 
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvements to published standards, addressed to t he Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
 
 
 
 
 
 
© Kenya Bureau of Standards, 2020 
  
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 12 of 2001 of  the Laws 
of Kenya, copyright subsists in all Ken ya Standards and except as provided under Section 26 of this Act, no 
Kenya Standard produced by Kenya Bureau of Standards may be reproduced, stored in a retrieval system in 
any form or transmitted by any means without prior permission in writing from the M anaging Director . 
 
 
 KENYA STANDARD                                  KS 2 767-11: 2020 
                
 © KEBS 2020 — All rights reserved            iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Wastewater treatment plants - Part 11: 
General data required  
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+ 254 020 ) 605490, 602350, Fax: (+254 020 ) 604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region     Lake Region          Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40   Tel.: (+254 057) 23549, 22396         Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814         
 
 
 
 
 
 
 
 
 KS 2 767-11: 2020                                                                                                    
        
 
iv                     © KEBS 2020 — All rights reser ved Foreword  
 
This Kenya Standard was prepared by the Sanitation and Water Treatment Technical  Committee under the 
guidance of the Standards Projects C ommittee and it is in accordance with the procedures of the Kenya 
Bureau of Standards  
 
The parts of these series are as follows:  
– Part 1: General construction principles  
– Part 3: Preliminary treatment  
– Part 4: Primary settlement  
– Part 5: Lagooning proc esses  
– Part 6: Activated sludge processes  
– Part 7: Biological fixed -film reactors  
– Part 8: Sludge treatment and storage  
– Part 9: Odour control and ventilation  
– Part 10: Safety principles  
– Part 11: General data required  
– Part 12: Control and automati zation 1) 
– Part 13: Chemical treatment  
– Part 14: Disinfection 1) 
– Part 15: Measurement of the oxygen transfer in clean water in activated sludge aeration tanks  
– Part 16: Physical (mechanical) filtration 1) 
 
In the preparation of this Kenya Standard, the f ollowing source was consulted extensively:  
 
EN 12255  Wastewater treatment plants - Part 11: General data required  
 
 
 
 
 
. 
 
                          KS 2 767-11: 2020  
 
 
© KEBS 2020 — All rights reserved           
    5  KENYA  STANDARD                    
 
Wastewater treatment plants - Part 11: General data required  
 
1.  Scope 
 
This Standard  specifies data which is necessary for the planning, design, bidding, performan ce guarantee s, 
construction, start-up and compliance testing of a wastewate r treatmen t plant or parts of it. 
 
Differen ces in wastewate r treatmen t throughou t have led to a variety of practices being developed . This standar d 
gives fundamenta l informat ion abou t the practices; this standar d has not attempte d to specify all available practices. 
 
 
2.   Normat ive references  
 
This Standard  incorporate s by dated or undate d referen ce, provisions from other publications. These normat ive 
referen ces are cited at the appropr iate places in the text and the publications are listed hereafter .  For dated 
referen ces, subsequen t amendment s to or revisions of any of these publications apply to this Standard  only when 
incorporate d in it by amendmen t or revision.  For undate d referen ces the latest edition of the publication referre d to 
applies (including amendment s). 
 
KS 2766 Wastewate r treatmen t – Vocabulary 
 
KS 6767 -1 Wastewate r treatmen t plants – Part 1: Genera l construction principles 
 
3.   Term s and definitions 
 
For the purpo ses of this Standard  the terms and definitions given in KS 2766 and the following apply: 
 
3.1.  
plant 
a new wastewate r treatmen t plant; an upgrad ing or extension of an existing wastewate r treatmen t plant or a part of 
a new or extende d wastewater treatment plant (e. g. sludg e handlin g facilities)  
 
3.2.  
client 
a municipality, city or other organ isation which intend s to build a wastewate r treatmen t plant or parts thereof , or its 
repre sentat ive  
 
3.3.  
functional  tender 
a tende r documen t that contains the design loads, a description of the site wher e the plant is to be erected, the 
relevant discharge limits and any additional requirements  
  
NOT E     Turn-key contra ctors design the plant on the basis of the requirement s and plans specified by the client (possibly with the assistance 
of a consulting engineer) and give bids on the plant as a whole in accordan ce with an overall guarantee . The turn-key contra ctor who secures the 
contra ct is responsible for the construction and the start-up of the plant as well as for the compliance with requirement s demande d in the tende r 
document s (turn-key project). 
 
3.4.  
sectional tender 
tende r document s prepare d for differen t sections of work for a plant 
 
NOT E    e. g. earth work, concrete work, mechanical equipment , electrical installations, buildings etc. A plant is norma lly designed by a consulting 
engineer. Differen t compan ies may get the comm ission for the different sections. A consulting engineer may be comm issioned to coordinate and 
to supervise the work. 
 
3.5.  
consulting engin eer 
an independen t engineer  commissioned  by the client designing a plant or parts of it and/o r supervising the 
construction 
 KS 2 767: 2020  
            
                              © KEBS 2020 — All rights reserved  6 NOT E    He may assist the client with any work prepar ing all or part of the tende r document s. He supervises the construct ion and check s the 
time schedu le and costs . The consu lting engineer has knowledge and experience in planning, design and operat ional aspects of wastewate r 
treatmen t plants. In some countr ies a special certification may be required. 
 
3.6.  
turn-key contractor 
a contra ctor building a plant or parts of it as a whole 
 
NOT E     The turn-key contra ctor is a compan y which has knowledge and experience in planning, design, construction and operat ional 
aspects of wastewate r treatmen t plants. 
 
4.   Client options 
 
The client decides whethe r a functional tende r or a sectional tende r shall be prepared.  
 
The client may comm ission a consulting engineer to carry out one or more of the following: 
 
– establish the design loads and data as described in clause 5; 
 
– prepar e the tende r document s for a functional tender;  
 
– design the plant and estimate the costs and prepar e the tende r document s for the sectional tender;  
 
– inspect the construction in case of functional tender ing; 
 
– supervise and coordinate the construction in case of sectional tender ing; 
 
– evaluate the bids on the tender s and to propo se which contra ctor or contra ctors (in case of sectional tender ing) 
should be comm issioned.  
 
 
5.   Basic design data requ ired 
 
Wher e applicable the following basic data either measured or estimate d shall be provided by the client or his 
repre sentat ive e. g. consulting engineer.  
 
5.1. Loading  data 
 
5.1.1.    Sewerage  system  
 
The data on the sewerage syste m shou ld include: 
 
 areas served by combined and/o r separat e sewer s; 
 
 proport ions of flows and loads from separat e and/o r comb ined sewer system s for all  weathe r cond itions; 
 
 storag e capac ity for storm water within the sewerage system;  
 
 potent ial to contro l and balance flows and loads within the sewerage system;  
 
 infiltration flows in all weathe r conditions and their seasonal fluctuations (wher e appropr iate); 
 
 septic and corrosive component s of the wastewater.  
 
 
5.1.2.   Population  served 
 
The data on the popu lation served shall include: 
popu lation connecte d to the sewerage system;  
 
 popu lation conne cted at start-up of the plant; 
 
 popu lation conne cted at design horizon; 
 
 seasonal variations of popu lation (e. g. holiday periods); 
                          KS 2 767-11: 2020  
 
 
© KEBS 2020 — All rights reserved           
    7   weekly variations of popu lation (e. g. movemen t of commut ing popu lation). 
 
 
5.1.3.    Significant  trades  and indust ries 
 
A list of trade s and industr ies which discharg e significant loads to the sewerage syste m shou ld include the following 
flows and loads e. g.: 
 
– COD , BOD5, KN, NH4-N, NO3-N, total phosphoru s, total suspende d solids 
, organ ic suspende d solids, salinity and alkalinity; 
 
shown as current , start-up, and design targe t data for: 
 
– hourly peak (m3/h, kg/h);  
 
– weekly peak day (m3/d, kg/d);  
 
– maximum weekly average (m3/week, kg/week);  
 
– annua l average (m3/a, kg/a).  
 
In addition, for trade s and industries with seasonal fluctuations the periods of high and low loads shall be included 
preferab ly as an annua l diagram.  
 
The client shall specify discharger s who hand le hazardou s, toxic or inhibitory mater ial and identify which precautions 
are necessary to prevent that hazardous, toxic or inhibitory mater ials being discharged.  
 
Organic discha rges with low biodeg radabilit y shoul d be specified.  
 
 
5.1.4.    Data  from  existing  wastewater treatment  plants  
 
The loading data and the operat ional results of the existing wastewate r treatmen t plants contain valuable informat ion. 
As a minimum the following data for at least the previous year shall be provided: 
 
– annua l wastewate r flow (m3/a), proport ions treate d physically, chemically and biologically; 
 
– average quant ity (m3/d) and compo sition of sludge with % solids, and % volatile solids conten t and heavy 
meta ls; 
 
– annua l quant ity of screenings, grit and floatab les; 
 
– average volume of liquor from sludge treatmen t (m3/d) and organ ic and nutrient content;  
 
– average quant ity of digester gas (m3/d); 
– energ y produ ced from digester gas kWh/a);  
 
–energ y consumed (kWh/a);  
 
– probabilit y plots and diagrams showing the following over a year wastewater flows (m3/d) and the daily loads 
of COD , BOD5, KN, NH4-N, NO3-N, total phosphoru s, total suspende d solids, organ ic suspende d solids, salinity 
and alkalinity; 
 
– seasonal temperatur e of the wastewate r or biological reactor temperature s over a year; 
 
– diurnal fluctuation of the wastewate r flow at all weathe r conditions; 
 
– peak flow at storm wate r conditions (m³/h);  
 
– amoun t and loads of other wastes than wastewate r being delivered to the plant (e. g. night soil) and 
 KS 2 767: 2020  
            
                              © KEBS 2020 — All rights reserved  8 – performan ce of the treatmen t plant . 
 
 
5.1.5.    Design  flows and loads  
 
The design flows and loads shall be based on the present flows and loads considering growt h or decrease of the 
popu lation, the trade s and the industries and future conne ctions of other commun ities, trade s and industries. If there 
are no mean s to measure the present flows and loads the design data may be based on the projected popu lation. 
In addition to the popu lation the specific dry weathe r flow, (popu lation. d), a peak factor considering storm water 
and infiltration wate r and the specific loads in g/ (popu lation.   d) of COD , BOD5, KN, NH4-N, NO3-N, total phosphoru s, 
total suspende d solids and organ ic suspende d solids have to be provided. Flows and loads of trade s and industries 
should be determ ined by measurement s at the sites. 
 
The following design data should be provided: 
 
– maximum hourly wastewate r flow Qmax (m3/s) reaching the plant and the probab le 
durat ion; 
– details of discharge limits for storm wate r e. g. after screening, grit chamber , primary sedimentat ion or other 
treatmen t to a receiving wate r or a retent ion basin; 
 
– design peak flow as rema ining maximum flow after storm wate r discharge  (m3/s) 
 
– diurnal variation of the flow at a typical dry weathe r working day (l/s); 
 
– design loads as appropr iate for the process in kg/h, kg/d, kg/wee k of COD , BOD5, KN, NH4-N, NO3-N, total 
phosphoru s, total suspende d solids and organ ic suspende d solids as well as the correspond ing volume of 
wastewater;  
 
– minimum daily and weekly ratios of COD/ N and COD/P;  
 
– in case of seasonal flow and load fluctuations, day-to-day variation of flow (m3/d) and loads (kg/d) of the main 
parame ters over a year; 
 
– seasonal temperatur e of the wastewate r over a year; 
– annua l volume of wastewate r (m3/a) and annua l loads (kg/a) of COD , BOD, KN, NH -N, total phosphoru s, total 
 
suspende d solids and organ ic suspende d solids. 
 
5.2.   Efflu ent quality, requirements for  the disposal of residues and sludge  
 
5.2.1.  Effluent  quality  
 
The requirement s of the discharge consent shall be provided. The mode of inspection (e. g. grab samples, 2-hour 
compo site samples, 24-hour compo site samples) and the requirement s to meet the consent standar d (e.g. perm itted 
annua l frequen cy of exceeding consent standard ) shall be provided. 
 
5.2.2.  Requirements  for storm  water overflow  discharge  
 
If there are special requirement s for storm wate r to be discharge d from the wastewate r treatmen t plant these shall 
be stated.  
 
5.2.3.  Requirements  for the residues  from  preliminary  treatment  
 
The requirement s for the disposal of the residues shall be stated , e. g. wate r conten t of screenings, organ ic content 
of grit, and whethe r separat e or co-disposal of grit, screenings and floatab le mater ial are perm itted. 
 
5.2.4.  Requirements  for sludge  disposal  
 
The mode of sludg e disposa l which is preferred by the client , e. g. at agricultu ral utilization , landfill , incine ration , co- 
incinerat ion at powe r stations or other industries, shall be stated as well as the appropr iate requirement s, e. g. 
stabilization , water content . If certain chemicals, (e. g. for mechanica l dewatering), are prohibite d these shall be 
identified. 
 
5.3. Site description  
                          KS 2 767-11: 2020  
 
 
© KEBS 2020 — All rights reserved           
    9  The site description shall include: 
 
5.3.1.    Plan s (maps)  of the site 
 
Plans (map s) of the site shall be provided indicating: 
 
 elevation of site; 
 GPS coordinates  
 
 contou r lines and topograph y; 
 
 site boundar y; 
 
 existing buildings and structures including existing wastewate r treatmen t plant; 
 
 all services including sewer s, rising mains, wate r mains, electrical  cables , telephon e cables , including 
informat ion on the capacity (e. g. pressure, voltage, flow); 
 
 service roads (including perm issible truck weight) and walkways; 
 
 access  from public road;  
 
 final effluent discharge point with maximum , minimum and average wate r level of receiving water.  
 
5.3.2.  Existing  wastewater treatment  plants  
 
The details of any existing treatmen t plant shall be described. Plans of layout and structures shall be provided. The 
condition of the concrete, service roads and the mechanical and electrical equipmen t shall be described. 
 
5.3.3.   Ground  geology,  ground water and climate  
 
Boreho le informat ion should be provided as follows: 
 
– special characteristics of soil and groun d wate r including information on possible contam ination; 
 
– location of the boreho les; 
 
– groun d conditions (e. g. clay, rock, sand);  
 
– maximum , minimum and average groundwate r levels. 
 
Climatic informat ion including temperature , humidity, winds etc. should be provided. 
 
5.3.4.    Spec ial site constraints  
 
Any special site constraints shall be stated and may include the following: 
 
– perm issible maximum height of any building or structure; 
 
– limits on odou r or noise emissions; 
 
– preservation of groundwate r levels; 
 
– preservation of environmen t and natura l habitat; 
 
– distances of any buildings from site boundar y; 
 
– any limits or restrictions on building, transport and operat ion; 
 
– any special construction mater ial requirement s. 
 
5.4.  Addition al data required 
 
The following data required for design should be stated by the client or his repre sentat ive: KS 2 767: 2020  
            
                              © KEBS 2020 — All rights reserved  10  
a) the minimum numbe r of parallel units; 
 
b) bypasses; 
 
c) stand-by equipment;  
 
d) requiremen t for stand-by powe r supply (kVA); 
 
e) any operat ional paramete r (e. g. sludge age, retent ion time, surface loading, sludge loading) specifically 
reque sted by the client; 
 
f) contro l and automat ion requirement s; 
 
g) design service life of equipment;  
 
h) truck weight for service roads; 
 
i) requirement s (spac e and equipment/furn iture) for workshops , laborator ies, store room s and offices; 
 
j) performan ce guarantee s for: 
 
– the plant performan ce at design load; the testing period in length and time of the year shall be stated;  
 
– the projected consumpt ion of powe r and chemicals; testing may be performe d togethe r with the before 
ment ioned testing; these tests may be reque sted for a lower load and/o r for anothe r period; 
 
– single units, e. g. screen, mixer, aerat ion equipment , digester. 
 
NOT E    In order to condu ct performan ce guarante e testing it may be necessary to install additional piping, meter ing and monitoring devices 
(see 5.6.2).  
 
5.5.  Time schedule 
 
a) For a sectional tende r all relevant contra ctual mile stones shall be stated and should include: 
 
– starting date of contra ctual delivering time; 
 
– anticipated time scale of the start-up and of the comm issioning of the plant; 
 
– the latest time scale for the contra ctor to repor t the construction and/o r installations ready for inspection and 
for take over.  
 
b) For a functional tende r all relevant contra ctual mile stones shall be stated and should include: 
 
– anticipated starting date of contra ctual delivering time (notice to proceed);  
 
– time scale for delivering the document s (draw ings appro val, appro val certificate); 
 
– time scale for overall functional test (comm issioning; comm issioning certificate); 
 
– time scale for provisional take-over and final take-over. 
 
NOT E   Depend ing on the specific national regulations the client with the help of the contra ctor should obtain the perm ission for the planne d 
treatm ent process and construction work from the author ities prior to the notice to proceed. This perm ission should be obtained befor e the final 
contra ct. 
 
5.6.  Start-up and guarantee testing 
 
5.6.1.    Start -up 
 
The client may ask for: 
 
– vocational training of personne l; 
 
– advice on the technology. 
 
5.6.2.   Guarantee  testing                           KS 2 767-11: 2020  
 
 
© KEBS 2020 — All rights reserved           
    11   
If performance guarantee s are requeste d, it shall be specifie d how the guarantee s are to be teste d and who will 
bear the costs. The client may ask for: 
 
– client and contra ctor perfor m testing in cooperat ion; 
 
– testing performe d by a qualified third party in co-operat ion with the client; 
 
– testing performe d by a qualified third party in co-operat ion with the contra ctor. 
 
The time frame and the method s for process and plant testing and chemical analysis shall be specified. 
 
5.7.  Operational cost infor mation 
 
The client should provide unit costs wher e appropr iate. Examples include: 
 
– personne l costs with indicatio n of trade and skill level;  
 
– electrical energ y; 
 
– fuel oil; 
 
– natura l gas; 
 
– chemicals (e. g. for phosphate precipitation, sludge dewater ing and denitrification); 
 
– disposal of residues (screenings and grit) depend ing on the mode of disposal as stated in 5.2.3;  
 
– disposal of sludge depend ing on the mode of disposal as stated in 5.2.4.  
 
6.  Document s to be prov ided by a turn-key contracto r or the consu lting engineer  
 
6.1.  Complete documents 
 
If the informat ion and data provided by the client are not sufficient for the design and the calculation of the 
costs additional informat ion shall be reque sted: 
 
a) by contra ctors immed iately after receiving the tende r documents or  
b) by a consulting engineer immed iately when needed.  
 
6.2.   Design options  
 
Norma lly the consulting engineer has to submit several options for which the costs are estimated . A turn-key 
contra ctor may also submit variants of the same treatmen t process. 
 
6.3.  Propo sed solution  
 
The offer of a turn-key contra ctor or the propo sed solution of the consulting engineer shall be presented by text and 
draw ings in detail in an agree d language . An abstract written for decision makers with no technical background 
should be provided. A list of abbre viations and symbols shall be attached. The process description shall be provided. 
It shall be explaine d how proces s objective s will be achieved.  
 
The technological and hydraulic calculations including referen ces shall be provided. The relevant design parameter 
for each offere d treatmen t process has to be adequate ly documente d to allow the client to assess the propo sed 
process. 
 
The procedure s to ensure how norma l operat ion is maintained during  periods of malfunction, break -down of 
equipmen t and units out of operat ion for maintenan ce shall be described. 
 
Within an agree d time scale the following genera l items (if applicable) shall be presented by text and draw ings in 
detail: 
 
– proces s contro l syste m (may be regarde d as part of the treatmen t process) , e. g. contro l pane l, computer - 
contro l, sub contro l stations, instrumentat ion for process contro l; KS 2 767: 2020  
            
                              © KEBS 2020 — All rights reserved  12  
– electrical power syste m including digeste r gas engines, transformers , cable arrangement , sub power meters, 
contro l station, peak powe r deman d (kVA); 
 
– lighting including types and luminous intensity, cables, switches; 
 
– taps and hydrant s for service water including the water distribution syste m as well as the water treatmen t plant 
if required; 
 
– service roads according to the load as stated in 5.4; 
 
– walkways; 
 
– workshop, office and storehou se buildings including equipmen t and furniture as stated in 5.4; 
 
– operat ing and maintenan ce manua ls. 
 
The propert ies of the mater ial for construction and of the equipmen t installed shall be specified. 
If not specified by the client the procedure s for start-up and testing shall be stated.  
 
6.4.  Calculation  and presentation of costs 
 
6.4.1.   Construction  costs  
 
Considering the particular conditions of the area and the site, the costs for the complete plant shall be calculate 
d.  
 
Different iation shall be made betwee n the costs for civil works (e. g. concrete tanks, houses, roads), the costs for 
mechanical equipmen t and the costs for electrical installations including monitoring and process contro l. 
 
In addition, the costs arising for start-up and guarante e testing shall be stated.  
 
6.4.2.   Operational  costs  
 
Considering the particular conditions of the process and the site the annua l operat ional costs shall be presented in 
accordan ce with flow and load based on the costs and prices as stated in 5.7 as follows: 
 
a) personne l costs : base d on number and skille d level required, working in shifts and/o r regula r working time; 
 
b) energ y costs: to be separate ly calculated for (wher e appropr iate): 
 
– raw wastewate r pump ing, 
– main treatmen t process (e. g. aerat ion, mixers, interna l pump ing, scrapers), 
– tertiary treatment,  
– sludge treatmen t including pump ing, mixing, mechanical dewater ing, 
– miscellaneou s (e. g. lighting, heating of buildings); 
 
based on the estimate d consumpt ion of (wher e appropr iate): 
 
– electrical energ y, 
– natura l gas, 
– digester gas, 
– fuel oil; 
 
c) costs for chemicals: to be separate ly calculated based on the estimate d consumpt ion wher e appropr iate for: 
 
– primary sedimentat ion for pre-precipitation and/o r flocculation, 
– biological reactors for phosphate precipitation, 
– biological reactors for denitrification, 
– final clarifiers or filters for phosphate precipitation, 
– final clarifiers or filters to improve solids remo val, 
– sludge to improve thickening, 
– sludge dewater ing; 
 
d) costs for disposal of residues and sludge : to be separate ly calculated based on the estimate d volume or mass 
wher e appropr iate for:                          KS 2 767-11: 2020  
 
 
© KEBS 2020 — All rights reserved           
    13   
– screenings, 
– grit, 
– grease and floatab les and 
– sludge;  
 
e) costs for maintenan ce of civil works and equipmen t shall be separate ly calculated wher e appropr iate for: 
 
– office buildings, workshops, store houses, laborator ies and other non-process buildings, 
– tanks and channe ls exposed to wastewate r or sludge,  
– pipes exposed to wastewater , sludge or gas, 
– plastic tanks and pipes exposed to wastewater , sludge or gas, 
– mechanical equipmen t including spare parts and lubricants, 
– electrical equipmen t including instrumentat ion and monitoring. 
 
6.4.3.    Presentation of  costs  
 
The client may comm ission a consulting engineer to estimate the costs as specified in 6.4.1 and 6.4.2 . The 
consulting engineer shall estimate the total annua l costs for alternat ives including capital costs. 
 
At sectional tender ing the contra ctors shall give bids on the costs for all items listed in the tende r document s. They 
may offer and state the costs of special solutions which are adequat e to that described in the tende r document s. 
 
A turn-key contra ctor shall give a bid on the costs as specified in 6.4.1 and 6.4.2 and as reque sted in the tender 
document s. 
 
Based on the bids the client shall be able to calculate the total annua l costs of the plant including capital costs using 
cost benef it analysis.