Research On The Feasibility Of Waterworks Sludge Used For Landscape Planting And Effects On Environment

Waterworks sludge from raw water purification process resulting in the filtermaterial and precipitates has similar characteristics with the common soils, andcompared with the sewage sludge, it has small number of Escherichia coli and lowerheavy metal content, reducing the health threats due to excessive bacteria and heavymetal pollutants. If the water supply of sludge for landscape planting can solve theproblem of shortage of culture substrate in the landscape planting. Therefoe, landapplications of waterworks sludge is very promising disposition. In this study, thewaterworks sludge mixed with the two kinds of soils as ground substance to plant TallFescue, Marigold and Globe amaranth, to explore the feasibility of wastewater sludgefor the landscape planting, and to find the effects of wastewater sludge on the soilenvironment. The conclusions as follows:(1)By measuring the waterworks sludge main characteristics content, such as pH,CEC (cation exchange capacity), EC (conductivity), OM (organic matter) and otherphysicochemical properties, the results show that: Wastewater sludge has similarcharacteristics with the common soils. It’s rich in the content of organic matter,nitrogen, phosphorus which is necessary nutrition elements for plant growth, all ofthose have important significance to the growth of plants. The high content ofaluminum in waterworks sludge has a certain influence on absorption and metabolismof nutrients. However, apply appropriate amount of fly ash can inhibit the hazards ofaluminum to the plant. Overall, water supply sludge used in landscape planting isfeasible.(2)Through a series of contrast potted experiments, comparing to the controlgroups without the addition of waterworks sludge, applying a certain amount ofwaterworks sludge could significantly promote the pot plants——Tall Fescue,Marigold and Globe amaranth’s growth, significantly, the growth indexes of plants infresh weight as well as the content of N, P, K, Ca, Mg and other nutrient contents instems and leaves are all increased in a certain degree. The increasing rates are18.6%~264%, 4.8%~267.4%, 0%~204.9%, 4.5%~69.9%, 4.2%~365.1%, 11.9%~67.1%,respectively. Applying excessive or less waterworks sludge is not conducive to thegrowth of plants. The waterworks sludge optimal ratio for plants growth is roughly 75% ~ 50%.(3)Examined the color of test plant leaf showed that the leaf color of plantapplying water supply sludge more green than the plant without. Therefore, applying acertain amount of waterworks sludge could promote the content of chlorophyll andenhance the ornamental value of landscape planting.(4)Through measuring the physicochemical properties of substrate, comparing tothe control groups without the addition of waterworks sludge, the EC, CEC and OM allincreased in a certain degree. It shows that applying a certain amount of waterworkssludge could improve the physicochemical properties of the substrate.