ABSTRACT
In order to beautify the urban environment and meet the high demand for
residential area in public places such as the cultural landscape and the natural
environment, in contemporary society, there are increasing cases on kinds of
waterscapes were introduced into living areas or other public places. Water pollution,
one of the key problems need solved right away, is becoming serious followed the
creation of hydrophilic natural environment. At the same time, urban sewage
treatments produce a large number of sludge. If handling improperly, the emissions
will cause serious secondary pollution. Therefore, how to disposal sludge in a
scientific, reasonable, safe, reliable and economic way, which is concerned by the
public, is an urgent issue which need to resolve. Based on the actual investigation of
48 sewage treatments and 7 enterprises in 13 districts in Shanghai, a kind of
ecological non-metallic mineral synthetic material was made without any
modification combined by microwave processing sludge, natural zeolite and cement.
This material is low energy consumption. It has compressive strength so that it can
keep a certain form in water. This new material can also remove nitrogen and
phosphorus simultaneously. Based on the characteristic of landscape water,
experiments about nitrogen and phosphorus removal were studied.
In this paper, static trail and dynamic test were designed and tested using the new
material containing sludge as the raw material. The processes are as followed:
Compared different material’s proportion, the best proportion is confirmed. The
mass ratio of cement, natural zeolite and sludge is 1:2:0.05, water cement ratio is 0.4,
the volume ratio of foaming agent and water is 1:60. With the best proportion, this
material was made into cubes or spheres. After curing process, they have good
waterproof and 5.8MPa compression strength in 7 days. These meet the requirement
of demonstration projects of channel revetment. With the help of Scanning Electron
Microscope, it shows that this synthetic material contains obvious channel and the
specific surface area of the material has increased.
The adsorption capacity of ammonia nitrogen and total phosphorus were studied
in the static trial, which could reach up to 229.8mg/kg and 321.4mg/kg respectively.
They conformed to the secondary dynamics model. From the static test, it also showed
that when ammonia nitrogen and total phosphorus coexist, the adsorption capacity of
the material decreased.
The paper also discussed the dynamic test of the synthetic materials dealing with
water pollution, which using the adsorptive property of the material and the biological
film inside. At the beginning, the removal of CODcr, ammonia nitrogen and total
phosphorus depended on the adsorption and filtration of the material. Small
fluctuation was showed by the indexes since biofilm had formed stability. In sludge-
tank CODcr removal rate was about 42%, ammonia nitrogen removal rate was about
19.8%, total phosphorus removal was about 40%, total nitrogen removal rate was
about 12.8%, TOC removal rate was about 23%. In all units, CODcr removal rate was
about 65%, ammonia nitrogen removal rate was about 34%, total phosphorus removal
was about 53%, total nitrogen removal rate was about 28%, TOC removal rate was