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®&M Considerations for STEP Systems
<br /> Mike Saunders I question is,What is a properly con-I a profound impact on the overall cost of
<br /> structed and maintained STEP system, 1 the STEP system.
<br /> Arever-rising number of com- and how can we identify one? O&M responsibilities for conven-
<br /> unfties and new develop- First,we must consider the qual- tfonal gravity sewer systems generally
<br /> erits are choosing waste-I ity of the STEP system,as well as the are limited to infrastructure located
<br /> water management solutions that use 1 system's major O&M protocols.The II within the public right-of-way.If this
<br /> alternative wastewater collection sys- quality of the system components must O&M policy is applied to a STEP sys-
<br /> tern technologies,such as the septic I provide the best value,rather than the I tern,it would be necessary to transfer
<br /> tank effluent pump(STEP).STEP sys- lowest initial capital cost.Protocols O&M responsibility for onsite com-
<br /> tems collect wastewater from each must be designed to ensure that the I ponents to the property owner,or,
<br /> property In an onsite 3800-to 5700-L system provides optimal service and alternatively,the onsite infrastructure
<br /> (1000-to 1500ga1)interceptor tank and is the most cost-effective option for the would have to be located within the
<br /> then pump screened primary effluent community.If a STEP system does not I public right-of-way.Successful STEP
<br /> to a treatment facility or neighboring satisfy these objectives,it is not prop- systems generally provide centralized
<br /> sewer.Most organic solids are retained erly constructed and maintained. I O&M fm'onsite infrastructure that
<br /> in the tank to degrade anaerobically The C&M costs for a STEP system is located on private property.The
<br /> while the screened effluent is conveyed can be broken into two major compo- costs for O&M are included in the fees
<br /> offsfte through small-diameter,shah nents.The first is the onsite system, charged to property owners.
<br /> lowlyburiedpressuremains. I which includes the tank,effluent filter, O&M typically is facilitated by a
<br /> ps and controls,building sewer,I combination of easements,service
<br /> Applied properly,STEP wastewater pum
<br /> _ .collection systems can offer.several- ._and_service`lateral.,The-second is the tariffs,and service agreements that
<br /> benefits for existing communities and conveyance component,which includes. are.intended to grant O&M personnel
<br /> new developments,including reduced the collection mains,air-release valves, access while preserving the rights of.
<br /> up-front capital costs,lower life-cycle odor-control filters,and shutoff valves. both the management entity and the
<br /> costs,and lower treatment costs than In the context of the overall waste- customer.In practice,homeowners are
<br /> conventional gravity sewer collection( water collection system cost,the almost always willing to grant access
<br /> systems. 0&M of STEP collection mains is to a STEP system on their property for
<br /> 'typically insignificant.Such an O&M I O&M,rather than maintain wastewater
<br /> Pinpointing O&M COStS program generally includes only valve infrastructure themselves.Functionally,
<br /> STEP systems often are selected maintenance in accordance with the S'PEP infrastructure located on private
<br /> because the construction costs for a manufacturer's recommendations property has provided an accessible,
<br /> gravity sewer collection system are and replacement of media in any ex- safe,and secure location for the com-
<br /> iprohibitive or because existing site iiting odor-control filters.Although I ponents and O&M without exposing the
<br /> conditions make Installing a gravity I most STEP systems are constructed system owner to increased liability.
<br /> sewer system logistically impractical. with cleanouts that facilitate pigging Same STEP systems have been
<br /> In most instances,STEP systems are( orff flushing the mains,this I-,rarely, in service more than 30 years.In
<br /> selected with anticipation of opera- ever,necessary.Breaks in or leaks Its simplest form,the STEP system
<br /> tions and maintenance(O&M)costs from collection mains are rare and can be achieved by using a standard
<br /> being higher than those of a compa- inexpensive to repair. I septic tank and placing a pump on a
<br /> �! table gravity sewer system. O&M costs for STEP systems are j concrete block.Conversely,a system
<br /> ost entirely attributable to the onsite can be a pre-engineered package that
<br /> STEP system manufacturers often alm
<br /> will state that"properly constructed components.The largest.proportion of I integrates the tank,pump,filter,and
<br /> and maintained"STEP systems can these costs is attributable to tank pump-I controls into a single package.In re,
<br /> provide comparable or possibly lower outs,filter cleaning,and pump replace-I ably,many of the older systems fall
<br /> long-term O&M costs than a gravity merit.O&M costs for major components somewhere in between.As the tech-
<br /> sewer system.Conversely,engineers ar m
<br /> e directly influenced by component nology has evolved,several anufac-
<br /> and utility operators will point to an I quality,installation quality,maintenance II turers have developed and marketed
<br /> existing STEP wastewater collection I Protocols,and ease of access to the site system components or,in some oases,
<br /> system as a testament to higher O&M for maintenance.Accordingly,the deci-i complete STEP packages.All compo-
<br /> ' costs.When we consider these two sions managers make about a limited rents or packages should be evalu-
<br /> opposing perspectives,the obvious 1 number of onsite O&M factors can have I ated carefully to establish the best
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