The WaCT DCA is complex tool, and while we have tried to make it intuitive and easy to use, this page presents answers to some of the questions asked by users. If you have a question that is not covered below, use the technical support link on the DCA main menu page and we will respond as quickly as we can.
Why does my DCA report "run-time error:" when I try to use it
The WaCT DCA contains macros and a full 'Visual Basic for Applications' (VBA) application, the most common cause of this error is when your Microsoft Excel installation's 'Trust Centre' settings are not permitting the VBA application to run. The Excel DCA user guide has an Annex describing how to change the 'Trust Centre' settings and install the DNA digital certificate that the spreadsheet application has been signed with (if running on a Windows PC). If you are using the application on an Apple Mac then you should only have to 'Enable macros' when prompted to do so. If you think that your settings are correct and you are still getting a run-time error reported, contact techical support and describe the action that you were undertaking when the error occured and we will investigate. The DCA is a very complex application, and while it has been extensively tested, it is quite possible there are unidentified residual 'bugs'.
Why is the DCA showing a higher than 100% collection rate
In order to get a true picture, and for the WaCT model to report correctly, it is necessary to ensure that data collected for waste generation correctly matches data collected for waste treatment and disposal. This is one of the trickiest aspects when applying the WaCT methodology and particularly when it comes to waste disposal data. It is important to carefully scrutinise waste input data to disposal facilities.
CATEGORIES OF WASTE PRODUCER
We only want to include municipal solid wastes generated by households and non-household sources:
We only want to include municipal solid wastes generated by households and non-household sources within the study area:
There are two important considerations here, firstly a disposal facility surveyed could be receiving wastes from outside the study area (these should be excluded), and secondly municipal solid wastes generated within the study area could be going to disposal facility outside the study area (in which case the 'remote' disposal facility needs to be surveyed). See also the question about negative values.
Why am I seeing a negative value in one of the waste flows
The WaCT DCA performs a 'Mass Flow Analysis' (MFA). An apparent negative value usually indicates that you are missing data. For example, if your disposal site data indicates 5 tonnes/day of recoverable wastes are being 'picked' for recovery by waste 'pickers', and your recovery facilities data indicates a total of only 4 tonnes per day received, then you will see -1 tonnes per day received by recovery facilities from household and non-household waste generators. In this case you are missing input data for recovery facilities (or you have over-estimated the 'picking'). Make sure you survey facilities receiving the 'picked' recoverable materials from landfill.
The figure below shows which values in the flow diagram you are actually measuring, and which are calculated, note that two values measured are not actually displayed in the DCA flow (total quantities received at recovery and disposal facilities - they are used to calculate input flows).
Waste collected from households and non-household generators and taken to disposal = total received at disposal less waste received from recovery operations (residues/rejects).
Waste collected from households and non-household generators and taken to recovery = total received at recovery less materials picked from disposal for recovery.
Waste disposed = total received at disposal facilities less materials picked for recovery.
Materials recovered = total received at recovery facilities less residues/rejects.
Note that if data is miss-matched, any of the calculated values could be negative - this indicates errors in the data. Note that a negative value in uncollected, which will correspond to a greater than 100% collection rate - again indicating there are errors in the data.
See also question 'I have created many records for inputs to materials recovery facilities, but I only see a small quantity of collected waste going to recovery (or a negative quantity), why is this?'
I have an Apple Mac computer, can I use the DCA
Yes you can, but V1.## does not support survey registration and upload to this data portal. Version 2 supports both Windows OS and Mac OS and does have full functionality, although the Mac OS does not handle PDF conversion of images well which renders images 'squashed' vertically which in turn affects the factsheet PDF pagination.
If you have a version 1.4# DCA and would like to use version 2.# send your DCA to us and we will import the data into the current Version 2.# and return it to you.
Can I use the WaCT DCA on an Android tablet
Sorry, no - the Android version of Excel does not support Visual Basic for Applications (VBA).
My city does not have readily identifiable lower, middle, and higher income level areas - what should I do
We suggest making a 'best guess' selecting residences by types and conditions of properties.
What do I do if my city does not have a disposal facility
The WaCT methodology uses a proxy percentage for rejects/residues from materials / energy recovery operations. It assumes that these quantities of waste are destined for disposal. We therefore recommend creating a 'dummy' record for a disposal facility with control level 'no control' and set the quantity received equal to the total residues/rejects from the various material / energy recovery facilities.
What do I do if my city has an Energy from Waste (EfW) facility (incinerator with energy recovery)
The WaCT methodology does not mention the need to undertake a waste characterisation study for wastes received at an EfW. However, if the facility operators are unable to provide information on the waste fractions received, a characterisation study should be performed sampling received waste using the same methodology as described for measuring the relative compositions received at waste disposal facilities, but using the recovery facility input waste types. This is important if the WaCT data is to be used as input data to a GIZ Waste Flow Diagram (WFD) assessment. If the EfW input is entered as 'Mixed waste' then the WaCT DCA flow model will assume the composition data for the country income level taken from the UNEP 2015 study on global MSW composition.
What do I do if my city is small and I can't identify 3 areas of a particular income level
It is possible to survey fewer areas, under 'Survey Configuration on tab 'Household settings' you can configure the survey for fewer survey areas per income level (defaults to 3) and fewer households per survey area (defaults to 10). Set these values to the lowest you need for your particular city; for example if you can only identify 1 high income area but 2 middle and lower income areaas, set the minimum number of survey areas per income level to 1.
My flow diagram / facsheet is not displaying nicely, what is the problem with it
This is probably an 'installed font' issue. The diagram and the factsheet use the 'Roboto' font favoured by UN-Habitat for publications.
When entering / viewing composition data I am seeing 'Average MSW' and there is no box for 'other', what is wrong
You have an early release of version 2.0 of the DCA, there is an issue with the translation lookup data all of the form labels are out of sync by one position. Please send the DCA to us at '[email protected]', with a covering email and we will import the data into a newer release which fixes this issue and return it to you.
I have filled in the online form requesting the DCA but I am not receiving a link to download it, what can I do
If the email with the link is not in your 'Spam' email folder, it may have been blocked by your email system, use the link below and ask for the DCA to be emailed to you.
I have created many records for inputs to materials recovery facilities, but I only see a small quantity of collected waste going to recovery (or a negative quantity), why is this
You have probably entered disposal site data with a large amount of 'picked' waste. The WaCT DCA assumes this waste is destined for material recovery. The recovery facility inputs data needs to account for this for the mass balance. You need to either survey the recovery operation(s) that this material is going to, or if the destination is not identifiable, create a recovery facility record to account for it, for example with the name 'Various informal recovery operations' and enter the picked waste as an input to that 'facility'.
See also 'Why am I seeing a negative value in one of the waste flows'.
I have a very large quantity of materials showing as going from 'disposal' to 'recovery', why is this
Waste 'picked' at disposal site(s) is assumed to go into the recovery system. This figure is calculated, by multiplying the number of pickers by the quantity each picker 'picks' in a day.
Some cities register pickers and because, for example, 5000 are registered, that does not necessarily mean that 5000 operate on the landfill every day. The figure entered in the WaCT DCA should be the number typically active on the disposal site(s) each day.