# 1. Introduction

Experimental data is stored in four separate databases, they are:

- wastemas.mdb - data pertaining to the waste mass
- gas.mdb - gas output and composition
- leachate.mdb - leachate composition, recirculation and recharge
- weather.mdb - climatological data

The format of the databases is Microsoft Access v2.0, but may be imported into many other contemporary software packages.

Databases are located in the directory datasets. There are no hypertexts links to the databases.

2. Database wastemas.mdb

The database contains information about sources of waste for the experiment, settlement of the waste mass, and temperature of the waste mass.

This is set out in five tables, as follows.

2.1 Table cunninghame input

The table provides information about every consignment of waste from the Cunninghame District Council’s Shewalton plant, which was the source of the pulverised waste for the experiment. In addition to the date and mass of each consignment in tonnes, the destination cell is given.

2.2 Table dumbarton input

The table provides similar information but for the Dumbarton District Council source of untreated waste. This waste was consigned directly by refuse collection vehicles, and the table contains an additional field source run, which gives information about the collection run, where this was known.

Because the waste was delivered directly, and the site did not have a weighbridge, only around 10% of consignments from Dumbarton were weighed. The balance of weighings were calculated on a vehicle specific basis.

2.3 Table inverclyde input

Consignments of untreated waste from Inverclyde District Council’s Port Glasgow waste transfer station are given in the table.

2.4 Table settlement monument reduced levels

The monitoring of the settlement monuments is carried out by level survey. A survey station has been established adjacent to the site, and this has been co-ordinated from an Ordnance Survey Bench Mark located on the bridge where Auchencarroch Road crosses Blairvault Burn (OS grid ref: NS408814). The reduced levels of the settlement monuments are given in metres above Ordnance Datum.

Each cell has six settlement monuments. Near the corners of each cell are A, B, E and F, while near the centre are C and D. Therefore the monument reference is in the form ‘nm’, where n is the Cell number and m in the monument letter.

2.5 Table wastemass temperature

In each cell there are two temperature probes, the ‘inner’ one at the centre of the cell, and the ‘outer’ one at the periphery. On each probe there are three thermocouples, roughly at the top, middle and bottom of the waste mass, numbered respectively 1 to 3.

The units are degrees Celcius. Between 11/9/96 and 23/10/96 a failure in the temperature measuring device meant that no data was recorded. On other occasions an individual thermocouple failure is recorded ‘nw’.

3. Database gas.mdb

3.1 Table gas flow - daily average(simple)

The dataset presented in this table is the daily average gas flow - a summary produced by the meter manufacturer during processing. This is a simple average of the successful readings during the day. However, in the extreme, only one successful reading out of a possible 144 may be taken as the daily average by this method.

Where no value is recorded, zero readings were successful, out of a possible 144. It should not be taken that this indicates that there was zero flow of gas.

This dataset covers the period 25/01/96 - 06/11/97. There is however a large gap in the data between 29/03/96 - 27/09/96 when the flow meters were not operational due to the flooding incident of 18/04/96.

3.2 Table gas flow - ten minute spot readings

The database consists of a single table containing a full record of all available ten minute gas flow data. The values are spot flow measurements in m3hr-1. Normal readings are taken at 10 minute intervals, on the hour, at 10, 20, 30 minutes past the hour and so on. Readings are taken at other times for the purposes of testing equipment, for instance at 1minute or 20 second intervals. The values recorded at these intervals should be ignored in calculations of gas flow.

The dataset covers the same period as the daily summary table, described above.

Blank cells indicate that a successful measurement of flow was not made for that event. This should not necessarily be taken to mean that there was zero flow.

A brief assessment of the data shows that there is some variability between consecutive readings and therefore single values should not be taken out of context of the mass of surrounding data. It can also be clearly seen that Cell 1 consistently has more successful measurement events than any other cell.

The Query daily flow by single points with compensation, calculates a composite flow rate for the day from this table. It considers a single reading to be indicative of the flow over that ten minute period alone, and compensates for no recorded reading by inserting a value of half the minimum threshold flow. The minimum threshold is given by the meter manufacturer as 0.8 m3/hr, although readings have been recorded down to about 0.2 m3/hr. Fifty percent of the former figure is used in the calculation. The advantages of this method of calculating a daily flow are discussed in the text of the thesis.

3.3 Table gas quality - routine measurements

Most parameters are measured on a weekly basis, with hydrogen and hydrogen sulphide being measured monthly. On a particular day there may be more than one reading, in which case an average has been used in calculations.

The values for each of the gas constituents is given in % by volume, apart from hydrogen and hydrogen sulphide which are in parts per million. Atmospheric pressure is in millibars and the gas temperature in degrees Celsius.

There are some gaps in the gas temperature field. At various times during the project the main instrument was out of service, for calibration etc., and the backup instrument did not have the capability to measure temperature. In addition, it is not possible to concurrently measure hydrogen concentration and gas temperature.

3.4 Table gas quality - twenty minute logging

The table shows the data collected during a trial in which gas composition and temperature was logged at twenty minute intervals for around one week on each of the cells.

4. Database leachate.mdb

4.1 Table leachate depth

The standing head of leachate in the Central Well is given in metres for each cell. Null values indicate no depth was recorded. Depth is recorded less frequently for Cell 4 than the other cells because the Central Well is not opened for recirculation on a weekly basis.

4.2 Table leachate quality

Leachate was sampled from the Central Well of each cell. Sampling and laboratory testing was conducted in duplicate, and therefore with the exception of temperature which was measured in the field, there are two values for each parameter and date. The average of these values is used to generate graphs presented in the following chapter.

The units are mg l-1, except for pH, Electrical Conductivity and temperature. EC is expressed as m S cm-1 at 25ºC, and temperature as ºC.

Some parameters are measured only on a quarterly or annual basis and therefore do not have a value at every sampling date.

4.3 Table leachate recirculation

Each record gives details of a recirculation event. In the case of Cell 2, the addition of water is also recorded. The fields are given as follows:

Field Name | Description
Cell | Cell identification
Date | Date
Leachate/Water | l/w leachate recirculation/water addition
Standing Head | Head of leachate in base of central well prior to pumping; same data as contained in ‘table leachate depth’ but over different period
Pump on | Time pump switched on
Pump off | Time pump switched off
Shortcirc | y/n/j Shortcircuiting down central well from top granular blanket: yes/no/just. His data was used to calculated leachate recirculation ceiling values for each cell.
Drum Test (s) | Flow rate. Time in seconds to pump 0.205 m3.
Volume | Total volume (m3) pumped during event. Not truncated at ceiling value.

4.4 Table recharge tests

The table shows the recharge of leachate after leachate recirculation. Logging of the leachate head by carried out at 15 minute intervals using an automated device. The data covers five consecutive recharge cycles, each of duration one week. There is a gap in the data of a few hours at the beginning of each cycle while pumping for recirculation was carried out. Data is presented for Cell 1 only. The dependent variable, 'Depth from Wellhead', is given in Field 3. The units are metres and the measurement was made from the top of the well down, thus as recharge occurs the values diminish.

5. Database weather.mdb

5.1 Table daily aws summary

Weather data is recorded on an hourly basis by the automatic weather station. The hourly data is given separately in the table hourly automatic weather station. The hourly dataset can be cumbersome to use due to the size, and so a daily summary dataset was created.

The fields in the daily summary are explained in the table below:

Field Name | Description
Av. wind speed | Average of hourly readings in knots
Wind drn @ 24hr | Bearing (degrees) of wind direction at end of day
Max wind speed | Largest of maximum hourly readings in knots
Time mws | Time of Max wind speed
Dir mws | Bearing (degrees) of direction of Max wind speed
Max dry bulb temp | Largest of hourly maximum dry bulb readings in ºC
Time of max temp | Hour during which max dry bulb temp occurred
Min dry bulb temp | Lowest of hourly minimum dry bulb readings in ºC
Time of min temp | Hour during which min dry bulb temp occurred
Min rel humidity | Minimum relative humidity as % of saturation
Time of min rh | Hour during which minimum relative humidity occurred
Daily ppt (mm) | Total precipitation recorded by automatic raingauge
Net radiation (kJ) | Net solar radiation, i.e. incoming less outgoing
Av. barom press (mb) | Average of hourly barometric pressure in millibars

There are a number of gaps in this dataset as follows:

> - Wind speeds and directions. An intermittent sensor caused gaps in the data in January, March and April '96.
> - All data. An involuntary system reset occurred at the beginning of December 96, causing the loss of all data for the whole of November 96. The system manufacturer (Didcot Instruments) attributes the involuntary reset to a nearby lightning strike.
> - Automatic raingauge. An intermittent problem caused by corrosion of electrical connections gave some erroneous results from January to March 97. The obviously rogue values have been removed from the dataset.
> - Net radiometer. The thin plastic dome on the sensor was found to be ruptured on 7th May 97. The sensor may not have been operating properly for up to a month prior to this, which was the last time it was checked. The repaired and recalibrated sensor was reinstalled on the 2nd July 97. On the 6th August 97, the dome was again found to be ruptured, this time more severely, the thermopile inside was also found to be damaged. The data shows that the damage probably occurred on 22nd July. Values on and after this date appear erroneous. Gull damage was suspected.

5.2 Table hourly automatic weather station

The table contains the hourly automatic weather station dataset from 12/10/95 to 5/10/97.

The database Form all hourly aws allows individual records to be easily viewed. It also shows the full titles of each of the fields, together with their units.

The format in which the automatic weather station stores date and time, means that this data is split over three fields. The field day stores the day of the year in the form ddmm, where dd is day number in the month, and mm is month number. It should be noted that fields containing time data omit leading zeros, and do not have a delimiter between hours and minutes; therefore five minutes past midnight is displayed as ‘5’.

The automatic raingauge is a tipping bucket device, measuring in increments of 0.5-mm precipitation. It should be noted therefore that during periods of low precipitation, 0.5-mm of precipitation is attributed to the hour during which the last of the precipitation required to make up the 0.5-mm increment occurs.

The gaps in the dataset are the same as those already described above in the table daily aws summary.

5.3 Table manual raingauge

A five inch Met Office Mark II manual raingauge was installed on 25th May 95, at the time when the topsoil strip for the construction of the experimental cells was beginning. The precipitation during the filling of the experimental cells was recorded by the manual raingauge alone, as commissioning of the automatic weather station was severely delayed. Since then, as a more reliable device, the manual raingauge, acts as a check on the automatic raingauge.

The table shows the weekly readings of the manual raingauge in millimetres precipitation. The two fields ‘time of reading’ and ‘rainfall status’ were included in observations after February 96 in order to make accurate comparisons with the automatic raingauge.

There are no hypertext links to the databases.