Environmental Engineering Reference
In-Depth Information
regarded as water quality objectives for the specified zones. However, the document does
not clarify this point. A positive improvement, which has been achieved in this regulatory
instrument, is the provision for unified standard methods for water quality assessments
and a prescription for sampling procedures in order to provide for a common basis of
comparison of the monitoring data. The document also prescribes administrative
procedures for practical implementation and provision of penalties.
Another positive development with respect to the regulatory aspects of water quality is
the incorporation of this document into the Environmental Management Act (EMA
2002), which allows for the protection of soils and air as well. In the past, the government
has been reluctant to impose land use controls on private property, as the sanctity of
private property is a vital part of freedoms in society, and is a strong emotional issue.
However, the EMA (2002) section 114 now addresses this weakness. An order may be
served to the owner, occupier or user of any land on controlling water, including storm
water, removing and disposing of litter or other refuse or waste from any land or premises
among other pollution sources. This necessitates the use of different land management
practices; changes that are not popular with landowners.
Considering the international trends in the development of regulatory instruments, and
the specifics of diffuse pollution control, it could be mentioned that there is one aspect of
the present regulatory documents in Zimbabwe, which needs improvement. In order to
help in the clear understanding and application of the regulations, consideration of the
random variability of water quality parameters should be made and the document should
define the basis for monitoring frequency and statistical data sets analysis, which would
determine the actual value of the constituents observed, and which could be compared to
the prescribed limits.
4.3
The monitoring programs
The City of Harare monitoring program is very wide in terms of a number of sampling
points and diversity of types of water monitored. It consists of several sub-programs with
different objectives and strategies to achieve them. The following sub-programs could be
differentiated:
• Water works control - this monitoring program aims to support the water treatment
process and the plant operation, as well as to provide for the quality assurance of the
water produced. The program includes basic parameters and is implemented on a
regular basis by the water laboratory of the city of Harare's water treatment works.
• Industrial effluent control - the monitoring program aims at the control of industrial
effluentsdischarged into the City's sewer system and is executed by the Waste Trade
Inspectorate - a unit especially designated to control such discharges through permits
and to monitor their implementation. This monitoring program includes only selected
locations and in terms of resources - technical, financial and human - does not have
the capacity to achieve its objectives. This results in a situation where the sewerage
system is receiving unauthorized discharges of different origin, which influences
adversely the wastewater treatment and disposal process.
• Sewage works control - this program aims at controlling the sewage treatment process
at all treatmentplants in the city. The program varies in terms of parameters tested and
locations, based on the type of the treatment process. More attention is given to the
