Environmental Engineering Reference
In-Depth Information
Phosphorous (soluble)
0.14
0.06
0.08
0.03
After: Debo & Reese 2003
3 DIFFUSE POLLUTION REDUCTION AND ABATEMENT
3.1
Source control
Source control of diffuse pollution consists of measures to prevent its generation and in
general, are aiming at the reduction of the quantity of the runoff (volumes and peak
flows), its erosive capacity and pollutants concentrations washed up by the flow before it
reaches the drainage system. Clearly, these are diffuse pollution prevention measures,
which could achieve a significant reduction effect if applied adequately, and are mostly
associated with diffuse pollution in urban areas. They should be applied where possible in
new development projects, but are also important in the process of improvement of the
existing practice of diffuse pollution management. In rural areas, diffuse pollution
abatement measures are related to proper agricultural practices and avoidance of over-
application of fertilizers, pesticides and herbicides. It should be emphasized and
remembered that the implementation of preventative measures does not consist of
specific engineering or scientific solutions only, but is a management philosophy based
on the implementation of a good housekeeping practice in urban communities.
3.1.1
Solid waste management and street cleaning
Litter (street refuse) includes large items and particulate material, such as paper, plastics,
food residues, glass bottles or particles, fallen leaves and other materials spread across
streets, parking zones and open spaces in urban areas. An adequate solid waste
management practice of regular waste collection, provision for waste collection
containers at all required places and regular street and open spaces cleaning could reduce
the level of diffuse pollution by 50%, especially in areas with a high percentage of
impervious surfaces (Novotny 2003). A higher level of reduction could be achieved in
developing countries, where improper solid waste collection and management practice is
usual.
3.1.2
Control of pervious areas
In areas of unprotected bare soils, which are prone to erosion, the soil loss might be
considerable, and would result in increased suspended solids concentrations in runoff and
deposition of solids in the drainage system and the receiving natural channels. In urban
areas, the suspended particles are usually the carriers of other pollutants as organic
materials, nutrients and toxic metals. Large construction sites and open mining operations
are major sources of such type of pollution. Pollution prevention activities consist in
erosion control measures, such as stabilization of soils and temporary or permanent soil
covers. Vegetation cover is an important erosion prevention measure and should be
applied where possible.
